Palestinian Board Part II cheat sheet

Nerve injury classification (Seddon): neurapraxia = reversible conduction block, no Wallerian degeneration; axonotmesis = axonal loss with intact endoneurium, spontaneous recovery; neurotmesis = complete transection, requires surgical repair.

Bone healing phases: hematoma/inflammation (days 1-7), soft callus (weeks 1-3), hard callus (weeks 3-12), remodeling (months to years); smoking, diabetes, and NSAIDs impair union.

Osteomyelitis organisms: Staphylococcus aureus most common; Salmonella in sickle cell disease; Pseudomonas in intravenous drug users and diabetic foot.

Fluid compartments: total body water ~60% body weight; intracellular ~40%, extracellular ~20% (interstitial 15%, plasma 5%); maintenance 4-2-1 rule (4 mL/kg/h first 10 kg, 2 mL/kg/h next 10 kg, 1 mL/kg/h thereafter).

Anion gap = Na+ − (Cl− + HCO3−); normal 8-12 mEq/L; elevated gap causes: methanol, uremia, diabetic ketoacidosis, paraldehyde, isoniazid, lactic acidosis, ethylene glycol, salicylates.

Coagulation cascade: intrinsic pathway measured by aPTT (heparin monitoring), extrinsic by PT/INR (warfarin monitoring); platelet count and fibrinogen assessed separately.

Renal clearance Cx = (Ux × V) / Px; creatinine clearance estimates GFR; Cockcroft-Gault: CrCl = [(140 − age) × weight] / (72 × serum creatinine), × 0.85 for females.

Cardiac output = heart rate × stroke volume; mean arterial pressure = diastolic + 1/3(systolic − diastolic); Fick principle: CO = oxygen consumption / arteriovenous oxygen difference.

Pharmacokinetics: volume of distribution Vd = dose / plasma concentration; half-life t½ = 0.693 × Vd / clearance; steady state reached after ~4-5 half-lives.

Sensitivity = TP/(TP+FN); specificity = TN/(TN+FP); positive predictive value depends on prevalence, so a sensitive test is best for ruling out (SnNout) and a specific test for ruling in (SpPin).

Likelihood ratio positive = sensitivity/(1 − specificity); LR > 10 substantially increases post-test probability; LR < 0.1 substantially decreases it.

Alvarado score for appendicitis: migratory pain, anorexia, nausea/vomiting, tenderness right lower quadrant, rebound, fever, leukocytosis, left shift; score ≥7 suggests appendicitis.

Glasgow Coma Scale: eye 1-4, verbal 1-5, motor 1-6; total 3-15; score ≤8 indicates need for airway protection.

Shock index = heart rate / systolic blood pressure; >0.9 suggests significant occult hemorrhage in trauma.

CAGE questionnaire for alcohol: Cut down, Annoyed, Guilty, Eye-opener; ≥2 positive answers indicate probable alcohol misuse.

Wells score for deep vein thrombosis: active cancer, paralysis, bedridden >3 days, tenderness along deep veins, whole-leg swelling, calf swelling >3 cm, pitting edema, collateral superficial veins, previous DVT, alternative diagnosis less likely.

Ottawa ankle rules: X-ray indicated if pain in malleolar zone plus bone tenderness at posterior edge of distal 6 cm of tibia/fibula or inability to bear weight four steps.

Pediatric assessment triangle: appearance, work of breathing, circulation to skin; used before hands-on examination in any ill child.

Acute coronary syndrome: aspirin 162-325 mg chewed plus P2Y12 inhibitor, anticoagulation, and reperfusion (primary PCI within 90 minutes of first medical contact for STEMI).

Diabetic ketoacidosis: isotonic saline, insulin infusion 0.1 units/kg/h after potassium ≥3.3 mEq/L confirmed, add dextrose when glucose <200-250 mg/dL, replace potassium.

Hypertensive emergency: reduce mean arterial pressure by no more than 25% in the first hour, then to 160/100 mmHg over 2-6 hours; avoid rapid drop in ischemic stroke.

Warfarin target INR: 2.0-3.0 for most indications (atrial fibrillation, venous thromboembolism); 2.5-3.5 for mechanical mitral valve.

Sepsis bundle: measure lactate, obtain blood cultures before antibiotics, broad-spectrum antibiotics within 1 hour of septic shock recognition, 30 mL/kg crystalloid for hypotension or lactate ≥4 mmol/L.

Asthma step-up: short-acting beta-agonist as needed; add low-dose inhaled corticosteroid; then combination low-dose ICS-formoterol; escalate to medium/high dose before oral corticosteroids.

Antibiotic de-escalation: review cultures at 48-72 hours, narrow spectrum, and set a stop date; duration for uncomplicated cystitis is 3-5 days, community pneumonia 5-7 days.

Opioid prescribing: check prescription monitoring program, offer naloxone when risk factors present (dose ≥50 morphine milligram equivalents/day, concurrent benzodiazepine, substance use history).

Universal precautions: hand hygiene before and after patient contact, gloves for body fluid exposure, eye protection when splash risk, safe sharps disposal in puncture-resistant container.

Central line insertion: maximal sterile barrier (cap, mask, sterile gown, gloves, full-body drape), chlorhexidine skin antisepsis, ultrasound guidance, confirm tip at cavoatrial junction before use.

Lumbar puncture: opening pressure measured in lateral decubitus; normal 10-20 cm H2O; contraindicated with signs of raised intracranial pressure or coagulopathy.

Local anesthetic maximum doses: lidocaine 4.5 mg/kg without epinephrine (7 mg/kg with epinephrine); bupivacaine 2.5 mg/kg; calculate before infiltration.

Surgical scrub and gowning: scrub 3-5 minutes to elbows, keep hands above elbows, dry hands first, gown without touching outside, gloves over cuff.

Suture selection: absorbable (vicryl, monocryl) for deep or mucosal layers; nonabsorbable (nylon, prolene) for skin; face 5-0 to 6-0, trunk 3-0 to 4-0.

Tourniquet use: exsanguinate limb, inflate to 100 mmHg above systolic (arm) or 150 mmHg above (leg); limit to 2 hours; document time.

Informed consent for procedures: capacity, disclosure of risks/benefits/alternatives, voluntariness, documentation; emergency exception applies when life-threatening and no surrogate available.

Adult cardiac arrest: high-quality chest compressions 100-120/min, depth 5-6 cm, full recoil, minimize interruptions; defibrillate shockable rhythms immediately; epinephrine 1 mg every 3-5 minutes.

Anaphylaxis: intramuscular epinephrine 0.3-0.5 mg (1:1000) into anterolateral thigh, repeat every 5-15 minutes; adjuncts are antihistamine, corticosteroid, fluids.

Tension pneumothorax: clinical diagnosis, immediate needle decompression at second intercostal space midclavicular line or fourth/fifth space anterior axillary line, then tube thoracostomy.

Acute stroke: noncontrast CT within 20 minutes of arrival; intravenous alteplase within 4.5 hours of symptom onset when no contraindication; thrombectomy up to 24 hours in selected large-vessel occlusion.

Status epilepticus: benzodiazepine first line (lorazepam 0.1 mg/kg IV), repeat once, then second-line (levetiracetam, fosphenytoin, valproate); intubate if refractory.

Massive transfusion protocol: balanced 1:1:1 ratio of packed red cells, plasma, platelets; permissive hypotension; tranexamic acid within 3 hours of trauma.

Acute decompensated heart failure: noninvasive ventilation for respiratory distress, intravenous loop diuretic, treat precipitants; avoid fluid bolus.

Rapid sequence intubation: preoxygenation, pretreatment as indicated, induction agent, neuromuscular blockade, intubation; confirm with continuous waveform capnography.

Hand hygiene moments: before patient contact, before aseptic task, after body fluid exposure risk, after patient contact, after touching surroundings.

Surgical site infection prevention: antibiotic prophylaxis within 60 minutes before incision, normothermia, glycemic control, hair removal by clipping not shaving.

Central line-associated bloodstream infection bundle: hand hygiene, maximal barrier precautions, chlorhexidine antisepsis, optimal site selection (subclavian preferred), daily review of line necessity.

WHO surgical safety checklist: sign in (before induction), time out (before incision), sign out (before leaving operating room).

Quality improvement model: Plan-Do-Study-Act cycles; measure with structure, process, and outcome indicators; run charts detect special-cause variation.

Root cause analysis: multidisciplinary, focuses on system failures rather than individual blame; produces actionable recommendations with owners and timelines.

Ventilator-associated pneumonia prevention: head of bed 30-45 degrees, daily sedation interruption, spontaneous breathing trials, oral care with chlorhexidine, subglottic suction.

Isolation precautions: contact for MRSA, VRE, Clostridioides difficile; droplet for influenza, pertussis, meningococcus; airborne for tuberculosis, measles, varicella.

Needlestick injury: wash with soap and water, report immediately, assess source for HIV, hepatitis B and C; post-exposure prophylaxis within hours for HIV.

Four principles of biomedical ethics: autonomy (respect patient choice), beneficence (act in patient's interest), nonmaleficence (avoid harm), justice (fair distribution).

Informed consent requires capacity, adequate disclosure, comprehension, and voluntariness; documentation in the record; surrogate decision-maker when capacity is lost.

Confidentiality exceptions: patient consent, legal requirement (reportable diseases, gunshot wounds), serious imminent harm to others, public health reporting.

Breaking bad news: SPIKES framework (Setting, Perception, Invitation, Knowledge, Empathy, Strategy/summary).

Medical error disclosure: disclose promptly, explain what happened, apologize, describe steps to prevent recurrence, document the conversation.

Conflict of interest: disclose gifts, industry relationships, and financial interests; recuse from decisions where personal interest conflicts with patient interest.

Capacity assessment: patient understands information, appreciates consequences, reasons with options, and communicates a choice; capacity is decision-specific.

Cultural competence: use professional interpreters, avoid family members as interpreters for consent, elicit patient's explanatory model of illness.

Study designs: randomized controlled trial strongest for causality; cohort for incidence and prognosis; case-control for rare outcomes; cross-sectional for prevalence.

Randomization reduces selection bias; blinding reduces measurement and observer bias; intention-to-treat analysis preserves randomization benefits.

Type I error (alpha) = false positive; type II error (beta) = false negative; power = 1 − beta, conventionally 0.80; sample size grows with variance and shrinks with larger effect size.

P value: probability of observing data as extreme assuming the null hypothesis is true; does not measure effect size or clinical importance.

Confidence interval: 95% CI excludes the null value if p < 0.05; narrower CI means greater precision.

Number needed to treat = 1 / absolute risk reduction; number needed to harm = 1 / absolute risk increase.

Odds ratio approximates relative risk when outcome is rare (<10%); use relative risk for cohort studies.

Levels of evidence: systematic reviews of randomized trials highest; then individual randomized trials; then cohort; then case-control; then case series and expert opinion.

Screening test criteria: important disease, detectable preclinical phase, acceptable and accurate test, effective early treatment, favorable benefits versus harms and cost.

Levels of prevention: primary (prevent disease before onset, e.g., vaccination), secondary (early detection, e.g., screening), tertiary (limit disability, e.g., rehabilitation).

Herd immunity threshold = 1 − 1/R0; for measles R0 ~12-18, requiring ~92-95% coverage.

Sensitivity and specificity of screening programs determine yield; predictive value depends on disease prevalence in the screened population.

Cost-effectiveness analysis: incremental cost-effectiveness ratio = (cost intervention − cost comparator) / (effect intervention − effect comparator); threshold often expressed per quality-adjusted life-year.

Antimicrobial stewardship: right drug, right dose, right duration; avoid antibiotics for viral upper respiratory infection; de-escalate based on culture.

Reportable disease surveillance: mandatory notification enables outbreak detection; syndromic surveillance uses pre-diagnostic data.

Resource allocation frameworks: triage by urgency, cost-effectiveness, and equity; transparent criteria reduce arbitrary decisions.

Universal health coverage: population coverage, service coverage, and financial protection; out-of-pocket spending above 15-20% of total health expenditure indicates financial hardship risk.

Nerve injury Seddon classification: neurapraxia (conduction block, reversible), axonotmesis (axonal loss, endoneurium intact, spontaneous recovery), neurotmesis (complete transection, surgical repair).

Bone healing phases: hematoma/inflammation (days 1-7), soft callus (weeks 1-3), hard callus (weeks 3-12), remodeling (months to years); smoking, diabetes, and NSAIDs impair union.

Osteomyelitis: Staphylococcus aureus most common; Salmonella in sickle cell disease; Pseudomonas in intravenous drug users and diabetic foot infections.

Maintenance fluids 4-2-1 rule: 4 mL/kg/h for first 10 kg, 2 mL/kg/h for next 10 kg, 1 mL/kg/h thereafter.

Anion gap = Na+ − (Cl− + HCO3−); normal 8-12 mEq/L; elevated in methanol, uremia, diabetic ketoacidosis, paraldehyde, isoniazid, lactic acidosis, ethylene glycol, salicylates.

Coagulation: aPTT monitors intrinsic pathway and heparin; PT/INR monitors extrinsic pathway and warfarin.

Creatinine clearance (Cockcroft-Gault) = [(140 − age) × weight] / (72 × serum creatinine), multiplied by 0.85 for females.

Cardiac output = heart rate × stroke volume; mean arterial pressure = diastolic + 1/3(systolic − diastolic).

Pharmacokinetics: volume of distribution = dose / plasma concentration; half-life = 0.693 × volume of distribution / clearance; steady state after ~4-5 half-lives.

Sensitivity = TP/(TP+FN); specificity = TN/(TN+FP); sensitive tests rule out (SnNout), specific tests rule in (SpPin).

Likelihood ratio positive = sensitivity/(1 − specificity); LR >10 substantially raises post-test probability; LR <0.1 substantially lowers it.

Alvarado score for appendicitis: migratory pain, anorexia, nausea/vomiting, right lower quadrant tenderness, rebound tenderness, fever, leukocytosis, left shift; score ≥7 suggests appendicitis.

Glasgow Coma Scale: eye 1-4, verbal 1-5, motor 1-6; total 3-15; score ≤8 indicates need for airway protection.

Shock index = heart rate / systolic blood pressure; >0.9 suggests significant occult hemorrhage in trauma.

CAGE questionnaire for alcohol misuse: Cut down, Annoyed, Guilty, Eye-opener; ≥2 positive answers indicate probable misuse.

Wells score for deep vein thrombosis: active cancer, paralysis, bedridden >3 days, deep vein tenderness, whole-leg swelling, calf swelling >3 cm, pitting edema, collateral veins, previous DVT, alternative diagnosis less likely.

Ottawa ankle rules: X-ray indicated if malleolar pain plus bone tenderness at posterior edge of distal 6 cm of tibia/fibula or inability to bear weight four steps.

Pediatric assessment triangle: appearance, work of breathing, circulation to skin; used before hands-on examination in any ill child.

Acute coronary syndrome: chew aspirin 162-325 mg plus P2Y12 inhibitor, anticoagulation, and reperfusion; primary PCI within 90 minutes of first medical contact for STEMI.

Diabetic ketoacidosis: isotonic saline, insulin infusion 0.1 units/kg/h after potassium ≥3.3 mEq/L confirmed, add dextrose when glucose <200-250 mg/dL, replace potassium.

Hypertensive emergency: reduce mean arterial pressure by no more than 25% in first hour, then to 160/100 mmHg over 2-6 hours; avoid rapid drop in ischemic stroke.

Warfarin target INR: 2.0-3.0 for atrial fibrillation and venous thromboembolism; 2.5-3.5 for mechanical mitral valve.

Sepsis bundle: measure lactate, obtain blood cultures before antibiotics, broad-spectrum antibiotics within 1 hour of septic shock recognition, 30 mL/kg crystalloid for hypotension or lactate ≥4 mmol/L.

Asthma step-up: short-acting beta-agonist as needed, then low-dose inhaled corticosteroid, then combination low-dose ICS-formoterol, then medium/high dose before oral corticosteroids.

Antibiotic de-escalation: review cultures at 48-72 hours, narrow spectrum, set stop date; uncomplicated cystitis 3-5 days, community pneumonia 5-7 days.

Opioid prescribing: check prescription monitoring program, offer naloxone when dose ≥50 morphine milligram equivalents/day, concurrent benzodiazepine, or substance use history.

Universal precautions: hand hygiene before and after patient contact, gloves for body fluid exposure, eye protection when splash risk, sharps disposal in puncture-resistant container.

Central line insertion: maximal sterile barrier, chlorhexidine skin antisepsis, ultrasound guidance, confirm tip at cavoatrial junction before use.

Lumbar puncture: opening pressure measured in lateral decubitus; normal 10-20 cm H2O; contraindicated with signs of raised intracranial pressure or coagulopathy.

Local anesthetic maximum doses: lidocaine 4.5 mg/kg without epinephrine (7 mg/kg with epinephrine); bupivacaine 2.5 mg/kg; calculate before infiltration.

Surgical scrub and gowning: scrub 3-5 minutes to elbows, keep hands above elbows, dry hands first, gown without touching outside, gloves over cuff.

Suture selection: absorbable (vicryl, monocryl) for deep or mucosal layers; nonabsorbable (nylon, prolene) for skin; face 5-0 to 6-0, trunk 3-0 to 4-0.

Tourniquet use: exsanguinate limb, inflate to 100 mmHg above systolic (arm) or 150 mmHg above (leg); limit to 2 hours; document time.

Informed consent for procedures: capacity, disclosure of risks/benefits/alternatives, voluntariness, documentation; emergency exception applies when life-threatening and no surrogate available.

Adult cardiac arrest: high-quality chest compressions 100-120/min, depth 5-6 cm, full recoil, minimize interruptions; defibrillate shockable rhythms immediately; epinephrine 1 mg every 3-5 minutes.

Anaphylaxis: intramuscular epinephrine 0.3-0.5 mg (1:1000) into anterolateral thigh, repeat every 5-15 minutes; adjuncts are antihistamine, corticosteroid, fluids.

Tension pneumothorax: clinical diagnosis, immediate needle decompression at second intercostal space midclavicular line or fourth/fifth space anterior axillary line, then tube thoracostomy.

Acute stroke: noncontrast CT within 20 minutes of arrival; intravenous alteplase within 4.5 hours of symptom onset when no contraindication; thrombectomy up to 24 hours in selected large-vessel occlusion.

Status epilepticus: benzodiazepine first line (lorazepam 0.1 mg/kg IV), repeat once, then second-line (levetiracetam, fosphenytoin, valproate); intubate if refractory.

Massive transfusion protocol: balanced 1:1:1 ratio of packed red cells, plasma, platelets; permissive hypotension; tranexamic acid within 3 hours of trauma.

Acute decompensated heart failure: noninvasive ventilation for respiratory distress, intravenous loop diuretic, treat precipitants; avoid fluid bolus.

Rapid sequence intubation: preoxygenation, pretreatment as indicated, induction agent, neuromuscular blockade, intubation; confirm with continuous waveform capnography.

Hand hygiene moments: before patient contact, before aseptic task, after body fluid exposure risk, after patient contact, after touching surroundings.

Surgical site infection prevention: antibiotic prophylaxis within 60 minutes before incision, normothermia, glycemic control, hair removal by clipping not shaving.

Central line-associated bloodstream infection bundle: hand hygiene, maximal barrier precautions, chlorhexidine antisepsis, optimal site selection (subclavian preferred), daily review of line necessity.

WHO surgical safety checklist: sign in before induction, time out before incision, sign out before leaving operating room.

Quality improvement model: Plan-Do-Study-Act cycles; measure structure, process, and outcome indicators; run charts detect special-cause variation.

Root cause analysis: multidisciplinary, focuses on system failures rather than individual blame; produces actionable recommendations with owners and timelines.

Ventilator-associated pneumonia prevention: head of bed 30-45 degrees, daily sedation interruption, spontaneous breathing trials, oral care with chlorhexidine, subglottic suction.

Isolation precautions: contact for MRSA, VRE, Clostridioides difficile; droplet for influenza, pertussis, meningococcus; airborne for tuberculosis, measles, varicella.

Needlestick injury: wash with soap and water, report immediately, assess source for HIV, hepatitis B and C; post-exposure prophylaxis within hours for HIV.

Four principles of biomedical ethics: autonomy (respect patient choice), beneficence (act in patient's interest), nonmaleficence (avoid harm), justice (fair distribution).

Informed consent requires capacity, adequate disclosure, comprehension, and voluntariness; documentation in the record; surrogate decision-maker when capacity is lost.

Confidentiality exceptions: patient consent, legal requirement (reportable diseases, gunshot wounds), serious imminent harm to others, public health reporting.

Breaking bad news: SPIKES framework (Setting, Perception, Invitation, Knowledge, Empathy, Strategy/summary).

Medical error disclosure: disclose promptly, explain what happened, apologize, describe steps to prevent recurrence, document the conversation.

Conflict of interest: disclose gifts, industry relationships, and financial interests; recuse from decisions where personal interest conflicts with patient interest.

Capacity assessment: patient understands information, appreciates consequences, reasons with options, and communicates a choice; capacity is decision-specific.

Cultural competence: use professional interpreters, avoid family members as interpreters for consent, elicit patient's explanatory model of illness.

Study designs: randomized controlled trial strongest for causality; cohort for incidence and prognosis; case-control for rare outcomes; cross-sectional for prevalence.

Randomization reduces selection bias; blinding reduces measurement and observer bias; intention-to-treat analysis preserves randomization benefits.

Type I error (alpha) = false positive; type II error (beta) = false negative; power = 1 − beta, conventionally 0.80; sample size grows with variance and shrinks with larger effect size.

P value: probability of observing data as extreme assuming the null hypothesis is true; does not measure effect size or clinical importance.

Confidence interval: 95% CI excludes the null value if p < 0.05; narrower CI means greater precision.

Number needed to treat = 1 / absolute risk reduction; number needed to harm = 1 / absolute risk increase.

Odds ratio approximates relative risk when outcome is rare (<10%); use relative risk for cohort studies.

Levels of evidence: systematic reviews of randomized trials highest; then individual randomized trials; then cohort; then case-control; then case series and expert opinion.

Screening test criteria: important disease, detectable preclinical phase, acceptable and accurate test, effective early treatment, favorable benefits versus harms and cost.

Levels of prevention: primary (prevent disease before onset, e.g., vaccination), secondary (early detection, e.g., screening), tertiary (limit disability, e.g., rehabilitation).

Herd immunity threshold = 1 − 1/R0; for measles R0 ~12-18, requiring ~92-95% coverage.

Sensitivity and specificity of screening programs determine yield; predictive value depends on disease prevalence in the screened population.

Cost-effectiveness analysis: incremental cost-effectiveness ratio = (cost intervention − cost comparator) / (effect intervention − effect comparator); threshold often expressed per quality-adjusted life-year.

Antimicrobial stewardship: right drug, right dose, right duration; avoid antibiotics for viral upper respiratory infection; de-escalate based on culture.

Reportable disease surveillance: mandatory notification enables outbreak detection; syndromic surveillance uses pre-diagnostic data.

Resource allocation frameworks: triage by urgency, cost-effectiveness, and equity; transparent criteria reduce arbitrary decisions.

Universal health coverage: population coverage, service coverage, and financial protection; out-of-pocket spending above 15-20% of total health expenditure indicates financial hardship risk.

Nerve injury Seddon classification: neurapraxia (conduction block, reversible), axonotmesis (axonal loss, endoneurium intact, spontaneous recovery), neurotmesis (complete transection, surgical repair).

Bone healing phases: hematoma/inflammation (days 1-7), soft callus (weeks 1-3), hard callus (weeks 3-12), remodeling (months to years); smoking, diabetes, and NSAIDs impair union.

Osteomyelitis: Staphylococcus aureus most common; Salmonella in sickle cell disease; Pseudomonas in intravenous drug users and diabetic foot infections.

Maintenance fluids 4-2-1 rule: 4 mL/kg/h for first 10 kg, 2 mL/kg/h for next 10 kg, 1 mL/kg/h thereafter.

Anion gap = Na+ − (Cl− + HCO3−); normal 8-12 mEq/L; elevated in methanol, uremia, diabetic ketoacidosis, paraldehyde, isoniazid, lactic acidosis, ethylene glycol, salicylates.

Coagulation: aPTT monitors intrinsic pathway and heparin; PT/INR monitors extrinsic pathway and warfarin.

Creatinine clearance (Cockcroft-Gault) = [(140 − age) × weight] / (72 × serum creatinine), multiplied by 0.85 for females.

Cardiac output = heart rate × stroke volume; mean arterial pressure = diastolic + 1/3(systolic − diastolic).

Pharmacokinetics: volume of distribution = dose / plasma concentration; half-life = 0.693 × volume of distribution / clearance; steady state after ~4-5 half-lives.

Sensitivity = TP/(TP+FN); specificity = TN/(TN+FP); sensitive tests rule out (SnNout), specific tests rule in (SpPin).

Likelihood ratio positive = sensitivity/(1 − specificity); LR >10 substantially raises post-test probability; LR <0.1 substantially lowers it.

Alvarado score for appendicitis: migratory pain, anorexia, nausea/vomiting, right lower quadrant tenderness, rebound tenderness, fever, leukocytosis, left shift; score ≥7 suggests appendicitis.

Glasgow Coma Scale: eye 1-4, verbal 1-5, motor 1-6; total 3-15; score ≤8 indicates need for airway protection.

Shock index = heart rate / systolic blood pressure; >0.9 suggests significant occult hemorrhage in trauma.

CAGE questionnaire for alcohol misuse: Cut down, Annoyed, Guilty, Eye-opener; ≥2 positive answers indicate probable misuse.

Wells score for deep vein thrombosis: active cancer, paralysis, bedridden >3 days, deep vein tenderness, whole-leg swelling, calf swelling >3 cm, pitting edema, collateral veins, previous DVT, alternative diagnosis less likely.

Ottawa ankle rules: X-ray indicated if malleolar pain plus bone tenderness at posterior edge of distal 6 cm of tibia/fibula or inability to bear weight four steps.

Pediatric assessment triangle: appearance, work of breathing, circulation to skin; used before hands-on examination in any ill child.

Acute coronary syndrome: chew aspirin 162-325 mg plus P2Y12 inhibitor, anticoagulation, and reperfusion; primary PCI within 90 minutes of first medical contact for STEMI.

Diabetic ketoacidosis: isotonic saline, insulin infusion 0.1 units/kg/h after potassium ≥3.3 mEq/L confirmed, add dextrose when glucose <200-250 mg/dL, replace potassium.

Hypertensive emergency: reduce mean arterial pressure by no more than 25% in first hour, then to 160/100 mmHg over 2-6 hours; avoid rapid drop in ischemic stroke.

Warfarin target INR: 2.0-3.0 for atrial fibrillation and venous thromboembolism; 2.5-3.5 for mechanical mitral valve.

Sepsis bundle: measure lactate, obtain blood cultures before antibiotics, broad-spectrum antibiotics within 1 hour of septic shock recognition, 30 mL/kg crystalloid for hypotension or lactate ≥4 mmol/L.

Asthma step-up: short-acting beta-agonist as needed, then low-dose inhaled corticosteroid, then combination low-dose ICS-formoterol, then medium/high dose before oral corticosteroids.

Antibiotic de-escalation: review cultures at 48-72 hours, narrow spectrum, set stop date; uncomplicated cystitis 3-5 days, community pneumonia 5-7 days.

Opioid prescribing: check prescription monitoring program, offer naloxone when dose ≥50 morphine milligram equivalents/day, concurrent benzodiazepine, or substance use history.

Universal precautions: hand hygiene before and after patient contact, gloves for body fluid exposure, eye protection when splash risk, sharps disposal in puncture-resistant container.

Central line insertion: maximal sterile barrier, chlorhexidine skin antisepsis, ultrasound guidance, confirm tip at cavoatrial junction before use.

Lumbar puncture: opening pressure measured in lateral decubitus; normal 10-20 cm H2O; contraindicated with signs of raised intracranial pressure or coagulopathy.

Local anesthetic maximum doses: lidocaine 4.5 mg/kg without epinephrine (7 mg/kg with epinephrine); bupivacaine 2.5 mg/kg; calculate before infiltration.

Surgical scrub and gowning: scrub 3-5 minutes to elbows, keep hands above elbows, dry hands first, gown without touching outside, gloves over cuff.

Suture selection: absorbable (vicryl, monocryl) for deep or mucosal layers; nonabsorbable (nylon, prolene) for skin; face 5-0 to 6-0, trunk 3-0 to 4-0.

Tourniquet use: exsanguinate limb, inflate to 100 mmHg above systolic (arm) or 150 mmHg above (leg); limit to 2 hours; document time.

Informed consent for procedures: capacity, disclosure of risks/benefits/alternatives, voluntariness, documentation; emergency exception applies when life-threatening and no surrogate available.

Adult cardiac arrest: high-quality chest compressions 100-120/min, depth 5-6 cm, full recoil, minimize interruptions; defibrillate shockable rhythms immediately; epinephrine 1 mg every 3-5 minutes.

Anaphylaxis: intramuscular epinephrine 0.3-0.5 mg (1:1000) into anterolateral thigh, repeat every 5-15 minutes; adjuncts are antihistamine, corticosteroid, fluids.

Tension pneumothorax: clinical diagnosis, immediate needle decompression at second intercostal space midclavicular line or fourth/fifth space anterior axillary line, then tube thoracostomy.

Acute stroke: noncontrast CT within 20 minutes of arrival; intravenous alteplase within 4.5 hours of symptom onset when no contraindication; thrombectomy up to 24 hours in selected large-vessel occlusion.

Status epilepticus: benzodiazepine first line (lorazepam 0.1 mg/kg IV), repeat once, then second-line (levetiracetam, fosphenytoin, valproate); intubate if refractory.

Massive transfusion protocol: balanced 1:1:1 ratio of packed red cells, plasma, platelets; permissive hypotension; tranexamic acid within 3 hours of trauma.

Acute decompensated heart failure: noninvasive ventilation for respiratory distress, intravenous loop diuretic, treat precipitants; avoid fluid bolus.

Rapid sequence intubation: preoxygenation, pretreatment as indicated, induction agent, neuromuscular blockade, intubation; confirm with continuous waveform capnography.

Hand hygiene moments: before patient contact, before aseptic task, after body fluid exposure risk, after patient contact, after touching surroundings.

Surgical site infection prevention: antibiotic prophylaxis within 60 minutes before incision, normothermia, glycemic control, hair removal by clipping not shaving.

Central line-associated bloodstream infection bundle: hand hygiene, maximal barrier precautions, chlorhexidine antisepsis, optimal site selection (subclavian preferred), daily review of line necessity.

WHO surgical safety checklist: sign in before induction, time out before incision, sign out before leaving operating room.

Quality improvement model: Plan-Do-Study-Act cycles; measure structure, process, and outcome indicators; run charts detect special-cause variation.

Root cause analysis: multidisciplinary, focuses on system failures rather than individual blame; produces actionable recommendations with owners and timelines.

Ventilator-associated pneumonia prevention: head of bed 30-45 degrees, daily sedation interruption, spontaneous breathing trials, oral care with chlorhexidine, subglottic suction.

Isolation precautions: contact for MRSA, VRE, Clostridioides difficile; droplet for influenza, pertussis, meningococcus; airborne for tuberculosis, measles, varicella.

Needlestick injury: wash with soap and water, report immediately, assess source for HIV, hepatitis B and C; post-exposure prophylaxis within hours for HIV.

Four principles of biomedical ethics: autonomy (respect patient choice), beneficence (act in patient's interest), nonmaleficence (avoid harm), justice (fair distribution).

Informed consent requires capacity, adequate disclosure, comprehension, and voluntariness; documentation in the record; surrogate decision-maker when capacity is lost.

Confidentiality exceptions: patient consent, legal requirement (reportable diseases, gunshot wounds), serious imminent harm to others, public health reporting.

Breaking bad news: SPIKES framework (Setting, Perception, Invitation, Knowledge, Empathy, Strategy/summary).

Medical error disclosure: disclose promptly, explain what happened, apologize, describe steps to prevent recurrence, document the conversation.

Conflict of interest: disclose gifts, industry relationships, and financial interests; recuse from decisions where personal interest conflicts with patient interest.

Capacity assessment: patient understands information, appreciates consequences, reasons with options, and communicates a choice; capacity is decision-specific.

Cultural competence: use professional interpreters, avoid family members as interpreters for consent, elicit patient's explanatory model of illness.

Study designs: randomized controlled trial strongest for causality; cohort for incidence and prognosis; case-control for rare outcomes; cross-sectional for prevalence.

Randomization reduces selection bias; blinding reduces measurement and observer bias; intention-to-treat analysis preserves randomization benefits.

Type I error (alpha) = false positive; type II error (beta) = false negative; power = 1 − beta, conventionally 0.80; sample size grows with variance and shrinks with larger effect size.

P value: probability of observing data as extreme assuming the null hypothesis is true; does not measure effect size or clinical importance.

Confidence interval: 95% CI excludes the null value if p < 0.05; narrower CI means greater precision.

Number needed to treat = 1 / absolute risk reduction; number needed to harm = 1 / absolute risk increase.

Odds ratio approximates relative risk when outcome is rare (<10%); use relative risk for cohort studies.

Levels of evidence: systematic reviews of randomized trials highest; then individual randomized trials; then cohort; then case-control; then case series and expert opinion.

Screening test criteria: important disease, detectable preclinical phase, acceptable and accurate test, effective early treatment, favorable benefits versus harms and cost.

Levels of prevention: primary (prevent disease before onset, e.g., vaccination), secondary (early detection, e.g., screening), tertiary (limit disability, e.g., rehabilitation).

Herd immunity threshold = 1 − 1/R0; for measles R0 ~12-18, requiring ~92-95% coverage.

Sensitivity and specificity of screening programs determine yield; predictive value depends on disease prevalence in the screened population.

Cost-effectiveness analysis: incremental cost-effectiveness ratio = (cost intervention − cost comparator) / (effect intervention − effect comparator); threshold often expressed per quality-adjusted life-year.

Antimicrobial stewardship: right drug, right dose, right duration; avoid antibiotics for viral upper respiratory infection; de-escalate based on culture.

Reportable disease surveillance: mandatory notification enables outbreak detection; syndromic surveillance uses pre-diagnostic data.

Resource allocation frameworks: triage by urgency, cost-effectiveness, and equity; transparent criteria reduce arbitrary decisions.

Universal health coverage: population coverage, service coverage, and financial protection; out-of-pocket spending above 15-20% of total health expenditure indicates financial hardship risk.

Nerve injury Seddon classification: neurapraxia (conduction block, reversible), axonotmesis (axonal loss, endoneurium intact, spontaneous recovery), neurotmesis (complete transection, surgical repair).

Bone healing phases: hematoma/inflammation (days 1-7), soft callus (weeks 1-3), hard callus (weeks 3-12), remodeling (months to years); smoking, diabetes, and NSAIDs impair union.

Osteomyelitis: Staphylococcus aureus most common; Salmonella in sickle cell disease; Pseudomonas in intravenous drug users and diabetic foot infections.

Maintenance fluids 4-2-1 rule: 4 mL/kg/h for first 10 kg, 2 mL/kg/h for next 10 kg, 1 mL/kg/h thereafter.

Anion gap = Na+ − (Cl− + HCO3−); normal 8-12 mEq/L; elevated in methanol, uremia, diabetic ketoacidosis, paraldehyde, isoniazid, lactic acidosis, ethylene glycol, salicylates.

Coagulation: aPTT monitors intrinsic pathway and heparin; PT/INR monitors extrinsic pathway and warfarin.

Creatinine clearance (Cockcroft-Gault) = [(140 − age) × weight] / (72 × serum creatinine), multiplied by 0.85 for females.

Cardiac output = heart rate × stroke volume; mean arterial pressure = diastolic + 1/3(systolic − diastolic).

Pharmacokinetics: volume of distribution = dose / plasma concentration; half-life = 0.693 × volume of distribution / clearance; steady state after ~4-5 half-lives.

Sensitivity = TP/(TP+FN); specificity = TN/(TN+FP); sensitive tests rule out (SnNout), specific tests rule in (SpPin).

Likelihood ratio positive = sensitivity/(1 − specificity); LR >10 substantially raises post-test probability; LR <0.1 substantially lowers it.

Alvarado score for appendicitis: migratory pain, anorexia, nausea/vomiting, right lower quadrant tenderness, rebound tenderness, fever, leukocytosis, left shift; score ≥7 suggests appendicitis.

Glasgow Coma Scale: eye 1-4, verbal 1-5, motor 1-6; total 3-15; score ≤8 indicates need for airway protection.

Shock index = heart rate / systolic blood pressure; >0.9 suggests significant occult hemorrhage in trauma.

CAGE questionnaire for alcohol misuse: Cut down, Annoyed, Guilty, Eye-opener; ≥2 positive answers indicate probable misuse.

Wells score for deep vein thrombosis: active cancer, paralysis, bedridden >3 days, deep vein tenderness, whole-leg swelling, calf swelling >3 cm, pitting edema, collateral veins, previous DVT, alternative diagnosis less likely.

Ottawa ankle rules: X-ray indicated if malleolar pain plus bone tenderness at posterior edge of distal 6 cm of tibia/fibula or inability to bear weight four steps.

Pediatric assessment triangle: appearance, work of breathing, circulation to skin; used before hands-on examination in any ill child.

Acute coronary syndrome: chew aspirin 162-325 mg plus P2Y12 inhibitor, anticoagulation, and reperfusion; primary PCI within 90 minutes of first medical contact for STEMI.

Diabetic ketoacidosis: isotonic saline, insulin infusion 0.1 units/kg/h after potassium ≥3.3 mEq/L confirmed, add dextrose when glucose <200-250 mg/dL, replace potassium.

Hypertensive emergency: reduce mean arterial pressure by no more than 25% in first hour, then to 160/100 mmHg over 2-6 hours; avoid rapid drop in ischemic stroke.

Warfarin target INR: 2.0-3.0 for atrial fibrillation and venous thromboembolism; 2.5-3.5 for mechanical mitral valve.

Sepsis bundle: measure lactate, obtain blood cultures before antibiotics, broad-spectrum antibiotics within 1 hour of septic shock recognition, 30 mL/kg crystalloid for hypotension or lactate ≥4 mmol/L.

Asthma step-up: short-acting beta-agonist as needed, then low-dose inhaled corticosteroid, then combination low-dose ICS-formoterol, then medium/high dose before oral corticosteroids.

Antibiotic de-escalation: review cultures at 48-72 hours, narrow spectrum, set stop date; uncomplicated cystitis 3-5 days, community pneumonia 5-7 days.

Opioid prescribing: check prescription monitoring program, offer naloxone when dose ≥50 morphine milligram equivalents/day, concurrent benzodiazepine, or substance use history.

Universal precautions: hand hygiene before and after patient contact, gloves for body fluid exposure, eye protection when splash risk, sharps disposal in puncture-resistant container.

Central line insertion: maximal sterile barrier, chlorhexidine skin antisepsis, ultrasound guidance, confirm tip at cavoatrial junction before use.

Lumbar puncture: opening pressure measured in lateral decubitus; normal 10-20 cm H2O; contraindicated with signs of raised intracranial pressure or coagulopathy.

Local anesthetic maximum doses: lidocaine 4.5 mg/kg without epinephrine (7 mg/kg with epinephrine); bupivacaine 2.5 mg/kg; calculate before infiltration.

Surgical scrub and gowning: scrub 3-5 minutes to elbows, keep hands above elbows, dry hands first, gown without touching outside, gloves over cuff.

Suture selection: absorbable (vicryl, monocryl) for deep or mucosal layers; nonabsorbable (nylon, prolene) for skin; face 5-0 to 6-0, trunk 3-0 to 4-0.

Tourniquet use: exsanguinate limb, inflate to 100 mmHg above systolic (arm) or 150 mmHg above (leg); limit to 2 hours; document time.

Informed consent for procedures: capacity, disclosure of risks/benefits/alternatives, voluntariness, documentation; emergency exception applies when life-threatening and no surrogate available.

Adult cardiac arrest: high-quality chest compressions 100-120/min, depth 5-6 cm, full recoil, minimize interruptions; defibrillate shockable rhythms immediately; epinephrine 1 mg every 3-5 minutes.

Anaphylaxis: intramuscular epinephrine 0.3-0.5 mg (1:1000) into anterolateral thigh, repeat every 5-15 minutes; adjuncts are antihistamine, corticosteroid, fluids.

Tension pneumothorax: clinical diagnosis, immediate needle decompression at second intercostal space midclavicular line or fourth/fifth space anterior axillary line, then tube thoracostomy.

Acute stroke: noncontrast CT within 20 minutes of arrival; intravenous alteplase within 4.5 hours of symptom onset when no contraindication; thrombectomy up to 24 hours in selected large-vessel occlusion.

Status epilepticus: benzodiazepine first line (lorazepam 0.1 mg/kg IV), repeat once, then second-line (levetiracetam, fosphenytoin, valproate); intubate if refractory.

Massive transfusion protocol: balanced 1:1:1 ratio of packed red cells, plasma, platelets; permissive hypotension; tranexamic acid within 3 hours of trauma.

Acute decompensated heart failure: noninvasive ventilation for respiratory distress, intravenous loop diuretic, treat precipitants; avoid fluid bolus.

Rapid sequence intubation: preoxygenation, pretreatment as indicated, induction agent, neuromuscular blockade, intubation; confirm with continuous waveform capnography.

Hand hygiene moments: before patient contact, before aseptic task, after body fluid exposure risk, after patient contact, after touching surroundings.

Surgical site infection prevention: antibiotic prophylaxis within 60 minutes before incision, normothermia, glycemic control, hair removal by clipping not shaving.

Central line-associated bloodstream infection bundle: hand hygiene, maximal barrier precautions, chlorhexidine antisepsis, optimal site selection (subclavian preferred), daily review of line necessity.

WHO surgical safety checklist: sign in before induction, time out before incision, sign out before leaving operating room.

Quality improvement model: Plan-Do-Study-Act cycles; measure structure, process, and outcome indicators; run charts detect special-cause variation.

Root cause analysis: multidisciplinary, focuses on system failures rather than individual blame; produces actionable recommendations with owners and timelines.

Ventilator-associated pneumonia prevention: head of bed 30-45 degrees, daily sedation interruption, spontaneous breathing trials, oral care with chlorhexidine, subglottic suction.

Isolation precautions: contact for MRSA, VRE, Clostridioides difficile; droplet for influenza, pertussis, meningococcus; airborne for tuberculosis, measles, varicella.

Needlestick injury: wash with soap and water, report immediately, assess source for HIV, hepatitis B and C; post-exposure prophylaxis within hours for HIV.

Four principles of biomedical ethics: autonomy (respect patient choice), beneficence (act in patient's interest), nonmaleficence (avoid harm), justice (fair distribution).

Informed consent requires capacity, adequate disclosure, comprehension, and voluntariness; documentation in the record; surrogate decision-maker when capacity is lost.

Confidentiality exceptions: patient consent, legal requirement (reportable diseases, gunshot wounds), serious imminent harm to others, public health reporting.

Breaking bad news: SPIKES framework (Setting, Perception, Invitation, Knowledge, Empathy, Strategy/summary).

Medical error disclosure: disclose promptly, explain what happened, apologize, describe steps to prevent recurrence, document the conversation.

Conflict of interest: disclose gifts, industry relationships, and financial interests; recuse from decisions where personal interest conflicts with patient interest.

Capacity assessment: patient understands information, appreciates consequences, reasons with options, and communicates a choice; capacity is decision-specific.

Cultural competence: use professional interpreters, avoid family members as interpreters for consent, elicit patient's explanatory model of illness.

Study designs: randomized controlled trial strongest for causality; cohort for incidence and prognosis; case-control for rare outcomes; cross-sectional for prevalence.

Randomization reduces selection bias; blinding reduces measurement and observer bias; intention-to-treat analysis preserves randomization benefits.

Type I error (alpha) = false positive; type II error (beta) = false negative; power = 1 − beta, conventionally 0.80; sample size grows with variance and shrinks with larger effect size.

P value: probability of observing data as extreme assuming the null hypothesis is true; does not measure effect size or clinical importance.

Confidence interval: 95% CI excludes the null value if p < 0.05; narrower CI means greater precision.

Number needed to treat = 1 / absolute risk reduction; number needed to harm = 1 / absolute risk increase.

Odds ratio approximates relative risk when outcome is rare (<10%); use relative risk for cohort studies.

Levels of evidence: systematic reviews of randomized trials highest; then individual randomized trials; then cohort; then case-control; then case series and expert opinion.

Screening test criteria: important disease, detectable preclinical phase, acceptable and accurate test, effective early treatment, favorable benefits versus harms and cost.

Levels of prevention: primary (prevent disease before onset, e.g., vaccination), secondary (early detection, e.g., screening), tertiary (limit disability, e.g., rehabilitation).

Herd immunity threshold = 1 − 1/R0; for measles R0 ~12-18, requiring ~92-95% coverage.

Sensitivity and specificity of screening programs determine yield; predictive value depends on disease prevalence in the screened population.

Cost-effectiveness analysis: incremental cost-effectiveness ratio = (cost intervention − cost comparator) / (effect intervention − effect comparator); threshold often expressed per quality-adjusted life-year.

Antimicrobial stewardship: right drug, right dose, right duration; avoid antibiotics for viral upper respiratory infection; de-escalate based on culture.

Reportable disease surveillance: mandatory notification enables outbreak detection; syndromic surveillance uses pre-diagnostic data.

Resource allocation frameworks: triage by urgency, cost-effectiveness, and equity; transparent criteria reduce arbitrary decisions.

Universal health coverage: population coverage, service coverage, and financial protection; out-of-pocket spending above 15-20% of total health expenditure indicates financial hardship risk.

Nerve injury Seddon classification: neurapraxia (conduction block, reversible), axonotmesis (axonal loss, endoneurium intact, spontaneous recovery), neurotmesis (complete transection, surgical repair).

Bone healing phases: hematoma/inflammation (days 1-7), soft callus (weeks 1-3), hard callus (weeks 3-12), remodeling (months to years); smoking, diabetes, and NSAIDs impair union.

Osteomyelitis: Staphylococcus aureus most common; Salmonella in sickle cell disease; Pseudomonas in intravenous drug users and diabetic foot infections.

Maintenance fluids 4-2-1 rule: 4 mL/kg/h for first 10 kg, 2 mL/kg/h for next 10 kg, 1 mL/kg/h thereafter.

Anion gap = Na+ − (Cl− + HCO3−); normal 8-12 mEq/L; elevated in methanol, uremia, diabetic ketoacidosis, paraldehyde, isoniazid, lactic acidosis, ethylene glycol, salicylates.

Coagulation: aPTT monitors intrinsic pathway and heparin; PT/INR monitors extrinsic pathway and warfarin.

Creatinine clearance (Cockcroft-Gault) = [(140 − age) × weight] / (72 × serum creatinine), multiplied by 0.85 for females.

Cardiac output = heart rate × stroke volume; mean arterial pressure = diastolic + 1/3(systolic − diastolic).

Pharmacokinetics: volume of distribution = dose / plasma concentration; half-life = 0.693 × volume of distribution / clearance; steady state after ~4-5 half-lives.

Sensitivity = TP/(TP+FN); specificity = TN/(TN+FP); sensitive tests rule out (SnNout), specific tests rule in (SpPin).

Likelihood ratio positive = sensitivity/(1 − specificity); LR >10 substantially raises post-test probability; LR <0.1 substantially lowers it.

Alvarado score for appendicitis: migratory pain, anorexia, nausea/vomiting, right lower quadrant tenderness, rebound tenderness, fever, leukocytosis, left shift; score ≥7 suggests appendicitis.

Glasgow Coma Scale: eye 1-4, verbal 1-5, motor 1-6; total 3-15; score ≤8 indicates need for airway protection.

Shock index = heart rate / systolic blood pressure; >0.9 suggests significant occult hemorrhage in trauma.

CAGE questionnaire for alcohol misuse: Cut down, Annoyed, Guilty, Eye-opener; ≥2 positive answers indicate probable misuse.

Wells score for deep vein thrombosis: active cancer, paralysis, bedridden >3 days, deep vein tenderness, whole-leg swelling, calf swelling >3 cm, pitting edema, collateral veins, previous DVT, alternative diagnosis less likely.

Ottawa ankle rules: X-ray indicated if malleolar pain plus bone tenderness at posterior edge of distal 6 cm of tibia/fibula or inability to bear weight four steps.

Pediatric assessment triangle: appearance, work of breathing, circulation to skin; used before hands-on examination in any ill child.

Acute coronary syndrome: chew aspirin 162-325 mg plus P2Y12 inhibitor, anticoagulation, and reperfusion; primary PCI within 90 minutes of first medical contact for STEMI.

Diabetic ketoacidosis: isotonic saline, insulin infusion 0.1 units/kg/h after potassium ≥3.3 mEq/L confirmed, add dextrose when glucose <200-250 mg/dL, replace potassium.

Hypertensive emergency: reduce mean arterial pressure by no more than 25% in first hour, then to 160/100 mmHg over 2-6 hours; avoid rapid drop in ischemic stroke.

Warfarin target INR: 2.0-3.0 for atrial fibrillation and venous thromboembolism; 2.5-3.5 for mechanical mitral valve.

Sepsis bundle: measure lactate, obtain blood cultures before antibiotics, broad-spectrum antibiotics within 1 hour of septic shock recognition, 30 mL/kg crystalloid for hypotension or lactate ≥4 mmol/L.

Asthma step-up: short-acting beta-agonist as needed, then low-dose inhaled corticosteroid, then combination low-dose ICS-formoterol, then medium/high dose before oral corticosteroids.

Antibiotic de-escalation: review cultures at 48-72 hours, narrow spectrum, set stop date; uncomplicated cystitis 3-5 days, community pneumonia 5-7 days.

Opioid prescribing: check prescription monitoring program, offer naloxone when dose ≥50 morphine milligram equivalents/day, concurrent benzodiazepine, or substance use history.

Universal precautions: hand hygiene before and after patient contact, gloves for body fluid exposure, eye protection when splash risk, sharps disposal in puncture-resistant container.

Central line insertion: maximal sterile barrier, chlorhexidine skin antisepsis, ultrasound guidance, confirm tip at cavoatrial junction before use.

Lumbar puncture: opening pressure measured in lateral decubitus; normal 10-20 cm H2O; contraindicated with signs of raised intracranial pressure or coagulopathy.

Local anesthetic maximum doses: lidocaine 4.5 mg/kg without epinephrine (7 mg/kg with epinephrine); bupivacaine 2.5 mg/kg; calculate before infiltration.

Surgical scrub and gowning: scrub 3-5 minutes to elbows, keep hands above elbows, dry hands first, gown without touching outside, gloves over cuff.

Suture selection: absorbable (vicryl, monocryl) for deep or mucosal layers; nonabsorbable (nylon, prolene) for skin; face 5-0 to 6-0, trunk 3-0 to 4-0.

Tourniquet use: exsanguinate limb, inflate to 100 mmHg above systolic (arm) or 150 mmHg above (leg); limit to 2 hours; document time.

Informed consent for procedures: capacity, disclosure of risks/benefits/alternatives, voluntariness, documentation; emergency exception applies when life-threatening and no surrogate available.

Adult cardiac arrest: high-quality chest compressions 100-120/min, depth 5-6 cm, full recoil, minimize interruptions; defibrillate shockable rhythms immediately; epinephrine 1 mg every 3-5 minutes.

Anaphylaxis: intramuscular epinephrine 0.3-0.5 mg (1:1000) into anterolateral thigh, repeat every 5-15 minutes; adjuncts are antihistamine, corticosteroid, fluids.

Tension pneumothorax: clinical diagnosis, immediate needle decompression at second intercostal space midclavicular line or fourth/fifth space anterior axillary line, then tube thoracostomy.

Acute stroke: noncontrast CT within 20 minutes of arrival; intravenous alteplase within 4.5 hours of symptom onset when no contraindication; thrombectomy up to 24 hours in selected large-vessel occlusion.

Status epilepticus: benzodiazepine first line (lorazepam 0.1 mg/kg IV), repeat once, then second-line (levetiracetam, fosphenytoin, valproate); intubate if refractory.

Massive transfusion protocol: balanced 1:1:1 ratio of packed red cells, plasma, platelets; permissive hypotension; tranexamic acid within 3 hours of trauma.

Acute decompensated heart failure: noninvasive ventilation for respiratory distress, intravenous loop diuretic, treat precipitants; avoid fluid bolus.

Rapid sequence intubation: preoxygenation, pretreatment as indicated, induction agent, neuromuscular blockade, intubation; confirm with continuous waveform capnography.

Hand hygiene moments: before patient contact, before aseptic task, after body fluid exposure risk, after patient contact, after touching surroundings.

Surgical site infection prevention: antibiotic prophylaxis within 60 minutes before incision, normothermia, glycemic control, hair removal by clipping not shaving.

Central line-associated bloodstream infection bundle: hand hygiene, maximal barrier precautions, chlorhexidine antisepsis, optimal site selection (subclavian preferred), daily review of line necessity.

WHO surgical safety checklist: sign in before induction, time out before incision, sign out before leaving operating room.

Quality improvement model: Plan-Do-Study-Act cycles; measure structure, process, and outcome indicators; run charts detect special-cause variation.

Root cause analysis: multidisciplinary, focuses on system failures rather than individual blame; produces actionable recommendations with owners and timelines.

Ventilator-associated pneumonia prevention: head of bed 30-45 degrees, daily sedation interruption, spontaneous breathing trials, oral care with chlorhexidine, subglottic suction.

Isolation precautions: contact for MRSA, VRE, Clostridioides difficile; droplet for influenza, pertussis, meningococcus; airborne for tuberculosis, measles, varicella.

Needlestick injury: wash with soap and water, report immediately, assess source for HIV, hepatitis B and C; post-exposure prophylaxis within hours for HIV.

Four principles of biomedical ethics: autonomy (respect patient choice), beneficence (act in patient's interest), nonmaleficence (avoid harm), justice (fair distribution).

Informed consent requires capacity, adequate disclosure, comprehension, and voluntariness; documentation in the record; surrogate decision-maker when capacity is lost.

Confidentiality exceptions: patient consent, legal requirement (reportable diseases, gunshot wounds), serious imminent harm to others, public health reporting.

Breaking bad news: SPIKES framework (Setting, Perception, Invitation, Knowledge, Empathy, Strategy/summary).

Medical error disclosure: disclose promptly, explain what happened, apologize, describe steps to prevent recurrence, document the conversation.

Conflict of interest: disclose gifts, industry relationships, and financial interests; recuse from decisions where personal interest conflicts with patient interest.

Capacity assessment: patient understands information, appreciates consequences, reasons with options, and communicates a choice; capacity is decision-specific.

Cultural competence: use professional interpreters, avoid family members as interpreters for consent, elicit patient's explanatory model of illness.

Study designs: randomized controlled trial strongest for causality; cohort for incidence and prognosis; case-control for rare outcomes; cross-sectional for prevalence.

Randomization reduces selection bias; blinding reduces measurement and observer bias; intention-to-treat analysis preserves randomization benefits.

Type I error (alpha) = false positive; type II error (beta) = false negative; power = 1 − beta, conventionally 0.80; sample size grows with variance and shrinks with larger effect size.

P value: probability of observing data as extreme assuming the null hypothesis is true; does not measure effect size or clinical importance.

Confidence interval: 95% CI excludes the null value if p < 0.05; narrower CI means greater precision.

Number needed to treat = 1 / absolute risk reduction; number needed to harm = 1 / absolute risk increase.

Odds ratio approximates relative risk when outcome is rare (<10%); use relative risk for cohort studies.

Levels of evidence: systematic reviews of randomized trials highest; then individual randomized trials; then cohort; then case-control; then case series and expert opinion.

Screening test criteria: important disease, detectable preclinical phase, acceptable and accurate test, effective early treatment, favorable benefits versus harms and cost.

Levels of prevention: primary (prevent disease before onset, e.g., vaccination), secondary (early detection, e.g., screening), tertiary (limit disability, e.g., rehabilitation).

Herd immunity threshold = 1 − 1/R0; for measles R0 ~12-18, requiring ~92-95% coverage.

Sensitivity and specificity of screening programs determine yield; predictive value depends on disease prevalence in the screened population.

Cost-effectiveness analysis: incremental cost-effectiveness ratio = (cost intervention − cost comparator) / (effect intervention − effect comparator); threshold often expressed per quality-adjusted life-year.

Antimicrobial stewardship: right drug, right dose, right duration; avoid antibiotics for viral upper respiratory infection; de-escalate based on culture.

Reportable disease surveillance: mandatory notification enables outbreak detection; syndromic surveillance uses pre-diagnostic data.

Resource allocation frameworks: triage by urgency, cost-effectiveness, and equity; transparent criteria reduce arbitrary decisions.

Universal health coverage: population coverage, service coverage, and financial protection; out-of-pocket spending above 15-20% of total health expenditure indicates financial hardship risk.

Nerve injury Seddon classification: neurapraxia (conduction block, reversible), axonotmesis (axonal loss, endoneurium intact, spontaneous recovery), neurotmesis (complete transection, surgical repair).

Bone healing phases: hematoma/inflammation (days 1-7), soft callus (weeks 1-3), hard callus (weeks 3-12), remodeling (months to years); smoking, diabetes, and NSAIDs impair union.

Osteomyelitis: Staphylococcus aureus most common; Salmonella in sickle cell disease; Pseudomonas in intravenous drug users and diabetic foot infections.

Maintenance fluids 4-2-1 rule: 4 mL/kg/h for first 10 kg, 2 mL/kg/h for next 10 kg, 1 mL/kg/h thereafter.

Anion gap = Na+ − (Cl− + HCO3−); normal 8-12 mEq/L; elevated in methanol, uremia, diabetic ketoacidosis, paraldehyde, isoniazid, lactic acidosis, ethylene glycol, salicylates.

Coagulation: aPTT monitors intrinsic pathway and heparin; PT/INR monitors extrinsic pathway and warfarin.

Creatinine clearance (Cockcroft-Gault) = [(140 − age) × weight] / (72 × serum creatinine), multiplied by 0.85 for females.

Cardiac output = heart rate × stroke volume; mean arterial pressure = diastolic + 1/3(systolic − diastolic).

Pharmacokinetics: volume of distribution = dose / plasma concentration; half-life = 0.693 × volume of distribution / clearance; steady state after ~4-5 half-lives.

Sensitivity = TP/(TP+FN); specificity = TN/(TN+FP); sensitive tests rule out (SnNout), specific tests rule in (SpPin).

Likelihood ratio positive = sensitivity/(1 − specificity); LR >10 substantially raises post-test probability; LR <0.1 substantially lowers it.

Alvarado score for appendicitis: migratory pain, anorexia, nausea/vomiting, right lower quadrant tenderness, rebound tenderness, fever, leukocytosis, left shift; score ≥7 suggests appendicitis.

Glasgow Coma Scale: eye 1-4, verbal 1-5, motor 1-6; total 3-15; score ≤8 indicates need for airway protection.

Shock index = heart rate / systolic blood pressure; >0.9 suggests significant occult hemorrhage in trauma.

CAGE questionnaire for alcohol misuse: Cut down, Annoyed, Guilty, Eye-opener; ≥2 positive answers indicate probable misuse.

Wells score for deep vein thrombosis: active cancer, paralysis, bedridden >3 days, deep vein tenderness, whole-leg swelling, calf swelling >3 cm, pitting edema, collateral veins, previous DVT, alternative diagnosis less likely.

Ottawa ankle rules: X-ray indicated if malleolar pain plus bone tenderness at posterior edge of distal 6 cm of tibia/fibula or inability to bear weight four steps.

Pediatric assessment triangle: appearance, work of breathing, circulation to skin; used before hands-on examination in any ill child.

Acute coronary syndrome: chew aspirin 162-325 mg plus P2Y12 inhibitor, anticoagulation, and reperfusion; primary PCI within 90 minutes of first medical contact for STEMI.

Diabetic ketoacidosis: isotonic saline, insulin infusion 0.1 units/kg/h after potassium ≥3.3 mEq/L confirmed, add dextrose when glucose <200-250 mg/dL, replace potassium.

Hypertensive emergency: reduce mean arterial pressure by no more than 25% in first hour, then to 160/100 mmHg over 2-6 hours; avoid rapid drop in ischemic stroke.

Warfarin target INR: 2.0-3.0 for atrial fibrillation and venous thromboembolism; 2.5-3.5 for mechanical mitral valve.

Sepsis bundle: measure lactate, obtain blood cultures before antibiotics, broad-spectrum antibiotics within 1 hour of septic shock recognition, 30 mL/kg crystalloid for hypotension or lactate ≥4 mmol/L.

Asthma step-up: short-acting beta-agonist as needed, then low-dose inhaled corticosteroid, then combination low-dose ICS-formoterol, then medium/high dose before oral corticosteroids.

Antibiotic de-escalation: review cultures at 48-72 hours, narrow spectrum, set stop date; uncomplicated cystitis 3-5 days, community pneumonia 5-7 days.

Opioid prescribing: check prescription monitoring program, offer naloxone when dose ≥50 morphine milligram equivalents/day, concurrent benzodiazepine, or substance use history.

Universal precautions: hand hygiene before and after patient contact, gloves for body fluid exposure, eye protection when splash risk, sharps disposal in puncture-resistant container.

Central line insertion: maximal sterile barrier, chlorhexidine skin antisepsis, ultrasound guidance, confirm tip at cavoatrial junction before use.

Lumbar puncture: opening pressure measured in lateral decubitus; normal 10-20 cm H2O; contraindicated with signs of raised intracranial pressure or coagulopathy.

Local anesthetic maximum doses: lidocaine 4.5 mg/kg without epinephrine (7 mg/kg with epinephrine); bupivacaine 2.5 mg/kg; calculate before infiltration.

Surgical scrub and gowning: scrub 3-5 minutes to elbows, keep hands above elbows, dry hands first, gown without touching outside, gloves over cuff.

Suture selection: absorbable (vicryl, monocryl) for deep or mucosal layers; nonabsorbable (nylon, prolene) for skin; face 5-0 to 6-0, trunk 3-0 to 4-0.

Tourniquet use: exsanguinate limb, inflate to 100 mmHg above systolic (arm) or 150 mmHg above (leg); limit to 2 hours; document time.

Informed consent for procedures: capacity, disclosure of risks/benefits/alternatives, voluntariness, documentation; emergency exception applies when life-threatening and no surrogate available.

Adult cardiac arrest: high-quality chest compressions 100-120/min, depth 5-6 cm, full recoil, minimize interruptions; defibrillate shockable rhythms immediately; epinephrine 1 mg every 3-5 minutes.

Anaphylaxis: intramuscular epinephrine 0.3-0.5 mg (1:1000) into anterolateral thigh, repeat every 5-15 minutes; adjuncts are antihistamine, corticosteroid, fluids.

Tension pneumothorax: clinical diagnosis, immediate needle decompression at second intercostal space midclavicular line or fourth/fifth space anterior axillary line, then tube thoracostomy.

Acute stroke: noncontrast CT within 20 minutes of arrival; intravenous alteplase within 4.5 hours of symptom onset when no contraindication; thrombectomy up to 24 hours in selected large-vessel occlusion.

Status epilepticus: benzodiazepine first line (lorazepam 0.1 mg/kg IV), repeat once, then second-line (levetiracetam, fosphenytoin, valproate); intubate if refractory.

Massive transfusion protocol: balanced 1:1:1 ratio of packed red cells, plasma, platelets; permissive hypotension; tranexamic acid within 3 hours of trauma.

Acute decompensated heart failure: noninvasive ventilation for respiratory distress, intravenous loop diuretic, treat precipitants; avoid fluid bolus.

Rapid sequence intubation: preoxygenation, pretreatment as indicated, induction agent, neuromuscular blockade, intubation; confirm with continuous waveform capnography.

Hand hygiene moments: before patient contact, before aseptic task, after body fluid exposure risk, after patient contact, after touching surroundings.

Surgical site infection prevention: antibiotic prophylaxis within 60 minutes before incision, normothermia, glycemic control, hair removal by clipping not shaving.

Central line-associated bloodstream infection bundle: hand hygiene, maximal barrier precautions, chlorhexidine antisepsis, optimal site selection (subclavian preferred), daily review of line necessity.

WHO surgical safety checklist: sign in before induction, time out before incision, sign out before leaving operating room.

Quality improvement model: Plan-Do-Study-Act cycles; measure structure, process, and outcome indicators; run charts detect special-cause variation.

Root cause analysis: multidisciplinary, focuses on system failures rather than individual blame; produces actionable recommendations with owners and timelines.

Ventilator-associated pneumonia prevention: head of bed 30-45 degrees, daily sedation interruption, spontaneous breathing trials, oral care with chlorhexidine, subglottic suction.

Isolation precautions: contact for MRSA, VRE, Clostridioides difficile; droplet for influenza, pertussis, meningococcus; airborne for tuberculosis, measles, varicella.

Needlestick injury: wash with soap and water, report immediately, assess source for HIV, hepatitis B and C; post-exposure prophylaxis within hours for HIV.

Four principles of biomedical ethics: autonomy (respect patient choice), beneficence (act in patient's interest), nonmaleficence (avoid harm), justice (fair distribution).

Informed consent requires capacity, adequate disclosure, comprehension, and voluntariness; documentation in the record; surrogate decision-maker when capacity is lost.

Confidentiality exceptions: patient consent, legal requirement (reportable diseases, gunshot wounds), serious imminent harm to others, public health reporting.

Breaking bad news: SPIKES framework (Setting, Perception, Invitation, Knowledge, Empathy, Strategy/summary).

Medical error disclosure: disclose promptly, explain what happened, apologize, describe steps to prevent recurrence, document the conversation.

Conflict of interest: disclose gifts, industry relationships, and financial interests; recuse from decisions where personal interest conflicts with patient interest.

Capacity assessment: patient understands information, appreciates consequences, reasons with options, and communicates a choice; capacity is decision-specific.

Cultural competence: use professional interpreters, avoid family members as interpreters for consent, elicit patient's explanatory model of illness.

Study designs: randomized controlled trial strongest for causality; cohort for incidence and prognosis; case-control for rare outcomes; cross-sectional for prevalence.

Randomization reduces selection bias; blinding reduces measurement and observer bias; intention-to-treat analysis preserves randomization benefits.

Type I error (alpha) = false positive; type II error (beta) = false negative; power = 1 − beta, conventionally 0.80; sample size grows with variance and shrinks with larger effect size.

P value: probability of observing data as extreme assuming the null hypothesis is true; does not measure effect size or clinical importance.

Confidence interval: 95% CI excludes the null value if p < 0.05; narrower CI means greater precision.

Number needed to treat = 1 / absolute risk reduction; number needed to harm = 1 / absolute risk increase.

Odds ratio approximates relative risk when outcome is rare (<10%); use relative risk for cohort studies.

Levels of evidence: systematic reviews of randomized trials highest; then individual randomized trials; then cohort; then case-control; then case series and expert opinion.

Screening test criteria: important disease, detectable preclinical phase, acceptable and accurate test, effective early treatment, favorable benefits versus harms and cost.

Levels of prevention: primary (prevent disease before onset, e.g., vaccination), secondary (early detection, e.g., screening), tertiary (limit disability, e.g., rehabilitation).

Herd immunity threshold = 1 − 1/R0; for measles R0 ~12-18, requiring ~92-95% coverage.

Sensitivity and specificity of screening programs determine yield; predictive value depends on disease prevalence in the screened population.

Cost-effectiveness analysis: incremental cost-effectiveness ratio = (cost intervention − cost comparator) / (effect intervention − effect comparator); threshold often expressed per quality-adjusted life-year.

Antimicrobial stewardship: right drug, right dose, right duration; avoid antibiotics for viral upper respiratory infection; de-escalate based on culture.

Reportable disease surveillance: mandatory notification enables outbreak detection; syndromic surveillance uses pre-diagnostic data.

Resource allocation frameworks: triage by urgency, cost-effectiveness, and equity; transparent criteria reduce arbitrary decisions.

Universal health coverage: population coverage, service coverage, and financial protection; out-of-pocket spending above 15-20% of total health expenditure indicates financial hardship risk.