EDIC Part I cheat sheet

KDIGO staging: stage 1 = creatinine rise ≥0.3 mg/dL within 48 h or 1.5–1.9× baseline; stage 2 = 2.0–2.9×; stage 3 = ≥3.0×, creatinine ≥4.0 mg/dL, or urine output <0.3 mL/kg/h for ≥24 h.

Urine output criteria: <0.5 mL/kg/h for 6–12 h = stage 1; ≥12 h = stage 2; ≥24 h or anuria ≥12 h = stage 3.

Prerenal vs intrinsic: fractional excretion of urea <35% suggests prerenal in patients on loop diuretics; FeNa <1% suggests prerenal when off diuretics.

Hepatorenal syndrome: cirrhosis with ascites, creatinine rise, no response to 2 days of albumin plus volume, absence of shock, no nephrotoxins, no structural renal disease; treated with terlipressin plus albumin.

Rhabdomyolysis: CK typically >5× upper limit; aggressive isotonic fluid resuscitation is the core therapy; watch for hyperkalaemia, hyperphosphataemia and hypocalcaemia.

Contrast-associated AKI risk rises with eGFR <30, diabetes, heart failure and volume depletion; use lowest contrast volume and isotonic crystalloid expansion in high-risk patients.

Renal replacement indications (AEIOU): refractory acidosis, electrolyte disturbance (hyperkalaemia), intoxication, fluid overload, uraemic complications such as pericarditis or encephalopathy.

Drug dosing: for renally cleared drugs adjust dose or interval by measured or estimated CrCl; continuous RRT affects dosing differently from intermittent haemodialysis.

Type 1 = hypoxaemic (PaO2 <60 mmHg on room air) with normal or low PaCO2; type 2 = hypercapnic with PaCO2 >50 mmHg.

Alveolar gas equation: PAO2 = FiO2 × (Patm − 47) − PaCO2/R, with R ≈ 0.8; A-a gradient distinguishes intrinsic from hypoventilation causes.

ARDS Berlin definition: onset within 1 week, bilateral opacities, not explained by cardiac failure, PEEP ≥5 cmH2O, and PaO2/FiO2 ≤300; severity mild 201–300, moderate 101–200, severe ≤100.

Lung-protective ventilation: tidal volume 6 mL/kg predicted body weight, plateau pressure ≤30 cmH2O, permissive hypercapnia and adequate PEEP.

Prone positioning for ≥16 h/day reduces mortality in moderate-severe ARDS (PaO2/FiO2 <150).

High-flow nasal oxygen typically delivers FiO2 up to 1.0 with flow 30–60 L/min and mild PEEP; ROX index (SpO2/FiO2 ÷ respiratory rate) predicts failure.

Non-invasive ventilation is first-line in acute hypercapnic COPD exacerbation with pH 7.25–7.35; avoid in unprotected airway, vomiting or facial trauma.

Recruitment manoeuvres and PEEP titration aim to reduce atelectrauma; watch for haemodynamic compromise and barotrauma.

ASA physical status: I healthy; II mild systemic disease; III severe systemic disease; IV constant threat to life; V moribund; suffix E for emergency.

RCRI (Revised Cardiac Risk Index) predictors: ischaemic heart disease, heart failure, cerebrovascular disease, insulin-treated diabetes, creatinine >2 mg/dL, and high-risk surgery (intraperitoneal, intrathoracic, suprainguinal vascular).

Mallampati classes I–IV grade oropharyngeal visibility; class III–IV predicts difficult laryngoscopy, combined with mouth opening, thyromental distance and neck mobility.

Succinylcholine is contraindicated in hyperkalaemia risk (burns, denervation, prolonged immobility) and malignant hyperthermia susceptibility; dantrolene is the antidote.

Malignant hyperthermia: rising ETCO2, masseter spasm, hyperthermia, acidosis and rhabdomyolysis; stop volatile agents, give dantrolene 2.5 mg/kg and cool.

Spinal anaesthesia causes sympathectomy-related hypotension; treat with fluids, vasopressors (phenylephrine) and left uterine displacement in obstetric patients.

Local anaesthetic systemic toxicity: stop injection, secure airway, give 20% lipid emulsion 1.5 mL/kg bolus then infusion, and avoid vasopressin, calcium channel blockers and beta-blockers.

Postoperative nausea and vomiting prophylaxis uses Apfel risk factors: female sex, non-smoker, history of PONV, and postoperative opioids.

Cardiac output = heart rate × stroke volume; stroke volume depends on preload, afterload and contractility.

Mean arterial pressure ≈ DBP + (SBP − DBP)/3; a MAP ≥65 mmHg is the usual resuscitation target in septic shock.

Frank-Starling relationship: increasing preload raises stroke volume until the plateau of the curve; dynamic indices (pulse pressure variation, SVV) predict fluid responsiveness better than static pressures.

Fick principle: CO = VO2 / (CaO2 − CvO2); thermodilution and pulse contour methods estimate CO from temperature or pressure waveforms.

Shock types: hypovolaemic, cardiogenic, distributive (septic, anaphylactic, neurogenic) and obstructive (tamponade, tension pneumothorax, pulmonary embolism).

Cardiac tamponade: Beck triad (hypotension, distended neck veins, muffled heart sounds), pulsus paradoxus, electrical alternans; treat with pericardiocentesis.

Anaphylaxis: intramuscular adrenaline 0.5 mg (0.5 mL of 1:1000) into the anterolateral thigh, repeated every 5 min; fluids and adjuncts follow.

ScvO2 <70% suggests inadequate oxygen delivery relative to demand; >80% with low CO may indicate impaired extraction or shunting.

Sensitivity = TP/(TP+FN); specificity = TN/(TN+FP); positive predictive value depends on prevalence.

Likelihood ratio positive = sensitivity/(1 − specificity); LR negative = (1 − sensitivity)/specificity.

Number needed to treat = 1/absolute risk reduction; ARR = control event rate − treatment event rate.

p value is the probability of data at least as extreme given the null hypothesis; it is not the probability that the null is true.

Confidence interval width narrows with larger sample size and reflects precision, not probability that the true value lies in a particular interval.

Receiver operating characteristic curve plots sensitivity against 1 − specificity; AUC of 0.5 is chance discrimination.

Randomised controlled trials reduce confounding by randomisation; intention-to-treat analysis preserves prognostic balance.

Odds ratio approximates relative risk only when the outcome is rare; for common outcomes OR overstates RR.

Four principles: autonomy, beneficence, non-maleficence and justice; autonomy generally dominates decisions for competent adults.

Informed consent requires capacity, adequate disclosure, comprehension and voluntariness; it is a process, not a signature.

Decision-making capacity: ability to understand, appreciate, reason and communicate a choice; assessed per decision, not globally.

Substituted judgement uses what the patient would have wanted; best interests standard applies when prior wishes are unknown.

Advance directives and lasting powers of attorney extend autonomy when capacity is lost; laws vary by jurisdiction.

Withholding and withdrawing life-sustaining treatment are ethically equivalent; both require proportionate justification.

Research ethics: Declaration of Helsinki and local review board approval; vulnerable populations need extra safeguards.

Confidentiality may be breached only where legally mandated or necessary to prevent serious harm, and disclosure should be minimal.

Enteral nutrition is preferred over parenteral when the gut works; it maintains mucosal integrity and reduces infection risk.

Start enteral feeding within 24–48 h in critically ill adults who cannot eat; trophic feeding is an option in shock with escalating vasopressors.

Energy target commonly 25–30 kcal/kg/day and protein 1.2–2.0 g/kg/day in critically ill adults, adjusted for obesity and renal or hepatic failure.

Refeeding syndrome: risk with low BMI, minimal intake >5 days, low phosphate or alcohol misuse; start low, monitor phosphate, potassium and magnesium, and give thiamine.

Gastric residual volume monitoring is no longer routine; prokinetics and post-pyloric feeding address intolerance.

Parenteral nutrition is indicated when enteral is contraindicated or insufficient after about 7 days in previously well-nourished patients.

Indirect calorimetry is the reference for measured energy expenditure when available.

Aspiration risk: elevate head of bed 30–45°, check tube position and consider post-pyloric feeding in high-risk patients.

Early mobilisation within 24–48 h of ICU admission is associated with reduced ICU-acquired weakness and shorter length of stay in stable patients.

ICU-acquired weakness is diagnosed clinically by Medical Research Council sum score <48/60; it predicts prolonged ventilation and mortality.

Passive range-of-motion exercises prevent contractures in sedated or paralysed patients; active exercise requires haemodynamic and respiratory stability.

Post-intensive care syndrome includes cognitive, psychological and physical impairment persisting after discharge; screen at follow-up.

Delirium prevention bundles: reorientation, sleep promotion, early mobilisation, analgesia-first sedation and family involvement.

Safety limits for mobilisation include MAP <60 mmHg, escalating vasopressors, active bleeding and unstable arrhythmias.

Pulmonary rehabilitation improves dyspnoea and exercise capacity in chronic respiratory disease; it includes endurance and strength training.

Swallowing assessment after prolonged intubation reduces aspiration risk before oral intake resumes.

Diabetic ketoacidosis: glucose >250 mg/dL, ketonaemia, pH <7.3 and bicarbonate <18; treat with isotonic fluid, insulin infusion and potassium replacement.

DKA potassium: total body potassium is depleted despite normal serum values; replace when K <5.5 mmol/L and hold insulin if K <3.3 mmol/L.

Hyperosmolar hyperglycaemic state: glucose >600 mg/dL, osmolality >320 mOsm/kg, minimal ketosis; fluid deficit is often large.

Adrenal crisis: hypotension unresponsive to fluids and vasopressors; give hydrocortisone 100 mg IV immediately, then 50 mg every 6 h; do not wait for cortisol results.

Thyroid storm: fever, tachycardia, agitation and altered mentation; treat with beta-blocker, thionamide, iodine after thionamide, and steroids.

Myxoedema coma: hypothermia, bradycardia, hypoventilation and reduced consciousness; give IV levothyroxine with stress-dose hydrocortisone.

SIADH: euvolaemic hyponatraemia with urine osmolality >100 mOsm/kg and urine sodium >30 mmol/L; treat with fluid restriction.

Stress hyperglycaemia in critical illness: target glucose roughly 140–180 mg/dL, avoiding hypoglycaemia.

Outcome measures: mortality, length of stay, readmission, quality-adjusted life years and patient-reported outcome measures.

QALY = survival time × health-related utility (0–1); used in cost-utility analysis.

Incremental cost-effectiveness ratio = (cost intervention − cost control)/(effect intervention − effect control); thresholds define cost-effectiveness.

Cohort studies estimate incidence and relative risk; case-control studies estimate odds ratios and suit rare outcomes.

Bias types: selection, information, confounding, and attrition; randomisation and blinding mitigate them.

Confounding can be addressed by stratification, multivariable regression, propensity scores or instrumental variables.

Number needed to harm = 1/absolute risk increase; report alongside NNT for balanced interpretation.

Benchmarking and risk adjustment are required before comparing hospital outcomes; standardised mortality ratio = observed/expected deaths.

Sepsis-3 defines sepsis as life-threatening organ dysfunction from infection, operationalised as a SOFA increase ≥2; septic shock adds vasopressor need and lactate >2 mmol/L despite fluids.

qSOFA: respiratory rate ≥22/min, altered mentation, systolic BP ≤100 mmHg; ≥2 identifies high risk outside ICU.

Blood cultures before antibiotics when this does not delay therapy; antibiotics within 1 h for septic shock and within 3 h for possible sepsis without shock.

Antimicrobial de-escalation: narrow spectrum based on culture results and clinical response; duration is often 7 days for common infections.

Ventilator-associated pneumonia: new infiltrate plus fever, purulent secretions and leukocytosis after 48 h of ventilation; sample with BAL or tracheal aspirate.

Clostridioides difficile: watery diarrhoea plus positive toxin or PCR; stop offending antibiotics and treat with oral vancomycin or fidaxomicin.

Meningococcal and influenza prophylaxis for contacts follows public health guidance; airborne precautions for tuberculosis and measles.

Therapeutic drug monitoring for vancomycin AUC/MIC and aminoglycoside troughs reduces nephrotoxicity.

Glasgow Coma Scale: eye 1–4, verbal 1–5, motor 1–6; score ≤8 generally indicates need for airway protection.

Cerebral perfusion pressure = MAP − intracranial pressure; typical CPP target 60–70 mmHg in traumatic brain injury.

Monro-Kellie doctrine: brain, blood and CSF occupy a fixed skull volume; an increase in one compartment must be offset by a decrease in another.

Intracranial hypertension: head elevation 30°, normocapnia (PaCO2 35–40 mmHg), osmotherapy with mannitol or hypertonic saline, and sedation.

Pupillary signs: fixed dilated pupil suggests uncal herniation; bilateral fixed pupils carry poor prognosis.

Status epilepticus: benzodiazepine first-line, then levetiracetam, valproate or phenytoin; refractory cases need anaesthetic doses and EEG monitoring.

Targeted temperature management after cardiac arrest: maintain 32–37.5 °C for at least 24 h, avoiding fever.

Subarachnoid haemorrhage: nimodipine reduces delayed ischaemic deficit; watch for rebleeding and hydrocephalus.

Noradrenaline is first-line vasopressor in septic shock; add vasopressin when noradrenaline dose exceeds about 0.25–0.5 µg/kg/min.

Dobutamine is an inotrope with beta-1 and mild beta-2 activity; it may cause tachycardia and hypotension from beta-2 vasodilation.

Propofol causes dose-dependent hypotension and hypertriglyceridaemia; prolonged high-dose infusion risks propofol infusion syndrome.

Midazolam is renally cleared and accumulates in renal failure; fentanyl and morphine have active metabolites, while remifentanil is organ-independent.

Aminoglycosides are concentration-dependent killers; extended-interval dosing and trough monitoring reduce toxicity.

Vancomycin requires AUC/MIC monitoring; infusion reactions (red man syndrome) are rate-related.

Heparin-induced thrombocytopenia: platelet fall >50% with thrombosis; stop heparin and start a non-heparin anticoagulant.

Cytochrome P450 interactions: CYP3A4 inhibitors (macrolides, azoles) raise levels of statins, tacrolimus and many sedatives.

Surviving Sepsis Campaign bundle: measure lactate, obtain cultures, give broad-spectrum antibiotics, start 30 mL/kg crystalloid for hypotension or lactate ≥4 mmol/L, and use vasopressors to target MAP ≥65 mmHg.

Lactate clearance is a resuscitation marker; persistently elevated lactate reflects ongoing hypoperfusion or impaired clearance.

SIRS criteria (temperature, heart rate, respiratory rate, white cell count) are sensitive but nonspecific; sepsis requires infection plus organ dysfunction.

Cytokine storm features: fever, cytopenias, hyperferritinaemia, high CRP and ferritin; consider haemophagocytic lymphohistiocytosis when criteria met.

Corticosteroids (hydrocortisone 200 mg/day) are reserved for septic shock with inadequate response to fluids and vasopressors.

Source control within 6–12 h is essential for sepsis from abscess, perforation or infected devices.

Balanced crystalloids may reduce hyperchloraemic acidosis compared with large-volume 0.9% saline.

Drotrecogin alfa and early goal-directed therapy with routine ScvO2 targets are not recommended in current practice.

KDIGO staging: stage 1 = creatinine rise ≥0.3 mg/dL within 48 h or 1.5–1.9× baseline; stage 2 = 2.0–2.9×; stage 3 = ≥3.0×, creatinine ≥4.0 mg/dL, or urine output <0.3 mL/kg/h for ≥24 h.

Urine output criteria: <0.5 mL/kg/h for 6–12 h = stage 1; ≥12 h = stage 2; ≥24 h or anuria ≥12 h = stage 3.

Prerenal vs intrinsic: fractional excretion of urea <35% suggests prerenal in patients on loop diuretics; FeNa <1% suggests prerenal when off diuretics.

Hepatorenal syndrome: cirrhosis with ascites, creatinine rise, no response to 2 days of albumin plus volume, absence of shock, no nephrotoxins, no structural renal disease; treated with terlipressin plus albumin.

Rhabdomyolysis: CK typically >5× upper limit; aggressive isotonic fluid resuscitation is the core therapy; watch for hyperkalaemia, hyperphosphataemia and hypocalcaemia.

Contrast-associated AKI risk rises with eGFR <30, diabetes, heart failure and volume depletion; use lowest contrast volume and isotonic crystalloid expansion in high-risk patients.

Renal replacement indications (AEIOU): refractory acidosis, electrolyte disturbance (hyperkalaemia), intoxication, fluid overload, uraemic complications such as pericarditis or encephalopathy.

Drug dosing: for renally cleared drugs adjust dose or interval by measured or estimated CrCl; continuous RRT affects dosing differently from intermittent haemodialysis.

Type 1 = hypoxaemic (PaO2 <60 mmHg on room air) with normal or low PaCO2; type 2 = hypercapnic with PaCO2 >50 mmHg.

Alveolar gas equation: PAO2 = FiO2 × (Patm − 47) − PaCO2/R, with R ≈ 0.8; A-a gradient distinguishes intrinsic from hypoventilation causes.

ARDS Berlin definition: onset within 1 week, bilateral opacities, not explained by cardiac failure, PEEP ≥5 cmH2O, and PaO2/FiO2 ≤300; severity mild 201–300, moderate 101–200, severe ≤100.

Lung-protective ventilation: tidal volume 6 mL/kg predicted body weight, plateau pressure ≤30 cmH2O, permissive hypercapnia and adequate PEEP.

Prone positioning for ≥16 h/day reduces mortality in moderate-severe ARDS (PaO2/FiO2 <150).

High-flow nasal oxygen typically delivers FiO2 up to 1.0 with flow 30–60 L/min and mild PEEP; ROX index (SpO2/FiO2 ÷ respiratory rate) predicts failure.

Non-invasive ventilation is first-line in acute hypercapnic COPD exacerbation with pH 7.25–7.35; avoid in unprotected airway, vomiting or facial trauma.

Recruitment manoeuvres and PEEP titration aim to reduce atelectrauma; watch for haemodynamic compromise and barotrauma.

ASA physical status: I healthy; II mild systemic disease; III severe systemic disease; IV constant threat to life; V moribund; suffix E for emergency.

RCRI (Revised Cardiac Risk Index) predictors: ischaemic heart disease, heart failure, cerebrovascular disease, insulin-treated diabetes, creatinine >2 mg/dL, and high-risk surgery (intraperitoneal, intrathoracic, suprainguinal vascular).

Mallampati classes I–IV grade oropharyngeal visibility; class III–IV predicts difficult laryngoscopy, combined with mouth opening, thyromental distance and neck mobility.

Succinylcholine is contraindicated in hyperkalaemia risk (burns, denervation, prolonged immobility) and malignant hyperthermia susceptibility; dantrolene is the antidote.

Malignant hyperthermia: rising ETCO2, masseter spasm, hyperthermia, acidosis and rhabdomyolysis; stop volatile agents, give dantrolene 2.5 mg/kg and cool.

Spinal anaesthesia causes sympathectomy-related hypotension; treat with fluids, vasopressors (phenylephrine) and left uterine displacement in obstetric patients.

Local anaesthetic systemic toxicity: stop injection, secure airway, give 20% lipid emulsion 1.5 mL/kg bolus then infusion, and avoid vasopressin, calcium channel blockers and beta-blockers.

Postoperative nausea and vomiting prophylaxis uses Apfel risk factors: female sex, non-smoker, history of PONV, and postoperative opioids.

Cardiac output = heart rate × stroke volume; stroke volume depends on preload, afterload and contractility.

Mean arterial pressure ≈ DBP + (SBP − DBP)/3; a MAP ≥65 mmHg is the usual resuscitation target in septic shock.

Frank-Starling relationship: increasing preload raises stroke volume until the plateau of the curve; dynamic indices (pulse pressure variation, SVV) predict fluid responsiveness better than static pressures.

Fick principle: CO = VO2 / (CaO2 − CvO2); thermodilution and pulse contour methods estimate CO from temperature or pressure waveforms.

Shock types: hypovolaemic, cardiogenic, distributive (septic, anaphylactic, neurogenic) and obstructive (tamponade, tension pneumothorax, pulmonary embolism).

Cardiac tamponade: Beck triad (hypotension, distended neck veins, muffled heart sounds), pulsus paradoxus, electrical alternans; treat with pericardiocentesis.

Anaphylaxis: intramuscular adrenaline 0.5 mg (0.5 mL of 1:1000) into the anterolateral thigh, repeated every 5 min; fluids and adjuncts follow.

ScvO2 <70% suggests inadequate oxygen delivery relative to demand; >80% with low CO may indicate impaired extraction or shunting.

Sensitivity = TP/(TP+FN); specificity = TN/(TN+FP); positive predictive value depends on prevalence.

Likelihood ratio positive = sensitivity/(1 − specificity); LR negative = (1 − sensitivity)/specificity.

Number needed to treat = 1/absolute risk reduction; ARR = control event rate − treatment event rate.

p value is the probability of data at least as extreme given the null hypothesis; it is not the probability that the null is true.

Confidence interval width narrows with larger sample size and reflects precision, not probability that the true value lies in a particular interval.

Receiver operating characteristic curve plots sensitivity against 1 − specificity; AUC of 0.5 is chance discrimination.

Randomised controlled trials reduce confounding by randomisation; intention-to-treat analysis preserves prognostic balance.

Odds ratio approximates relative risk only when the outcome is rare; for common outcomes OR overstates RR.

Four principles: autonomy, beneficence, non-maleficence and justice; autonomy generally dominates decisions for competent adults.

Informed consent requires capacity, adequate disclosure, comprehension and voluntariness; it is a process, not a signature.

Decision-making capacity: ability to understand, appreciate, reason and communicate a choice; assessed per decision, not globally.

Substituted judgement uses what the patient would have wanted; best interests standard applies when prior wishes are unknown.

Advance directives and lasting powers of attorney extend autonomy when capacity is lost; laws vary by jurisdiction.

Withholding and withdrawing life-sustaining treatment are ethically equivalent; both require proportionate justification.

Research ethics: Declaration of Helsinki and local review board approval; vulnerable populations need extra safeguards.

Confidentiality may be breached only where legally mandated or necessary to prevent serious harm, and disclosure should be minimal.

Enteral nutrition is preferred over parenteral when the gut works; it maintains mucosal integrity and reduces infection risk.

Start enteral feeding within 24–48 h in critically ill adults who cannot eat; trophic feeding is an option in shock with escalating vasopressors.

Energy target commonly 25–30 kcal/kg/day and protein 1.2–2.0 g/kg/day in critically ill adults, adjusted for obesity and renal or hepatic failure.

Refeeding syndrome: risk with low BMI, minimal intake >5 days, low phosphate or alcohol misuse; start low, monitor phosphate, potassium and magnesium, and give thiamine.

Gastric residual volume monitoring is no longer routine; prokinetics and post-pyloric feeding address intolerance.

Parenteral nutrition is indicated when enteral is contraindicated or insufficient after about 7 days in previously well-nourished patients.

Indirect calorimetry is the reference for measured energy expenditure when available.

Aspiration risk: elevate head of bed 30–45°, check tube position and consider post-pyloric feeding in high-risk patients.

Early mobilisation within 24–48 h of ICU admission is associated with reduced ICU-acquired weakness and shorter length of stay in stable patients.

ICU-acquired weakness is diagnosed clinically by Medical Research Council sum score <48/60; it predicts prolonged ventilation and mortality.

Passive range-of-motion exercises prevent contractures in sedated or paralysed patients; active exercise requires haemodynamic and respiratory stability.

Post-intensive care syndrome includes cognitive, psychological and physical impairment persisting after discharge; screen at follow-up.

Delirium prevention bundles: reorientation, sleep promotion, early mobilisation, analgesia-first sedation and family involvement.

Safety limits for mobilisation include MAP <60 mmHg, escalating vasopressors, active bleeding and unstable arrhythmias.

Pulmonary rehabilitation improves dyspnoea and exercise capacity in chronic respiratory disease; it includes endurance and strength training.

Swallowing assessment after prolonged intubation reduces aspiration risk before oral intake resumes.

Diabetic ketoacidosis: glucose >250 mg/dL, ketonaemia, pH <7.3 and bicarbonate <18; treat with isotonic fluid, insulin infusion and potassium replacement.

DKA potassium: total body potassium is depleted despite normal serum values; replace when K <5.5 mmol/L and hold insulin if K <3.3 mmol/L.

Hyperosmolar hyperglycaemic state: glucose >600 mg/dL, osmolality >320 mOsm/kg, minimal ketosis; fluid deficit is often large.

Adrenal crisis: hypotension unresponsive to fluids and vasopressors; give hydrocortisone 100 mg IV immediately, then 50 mg every 6 h; do not wait for cortisol results.

Thyroid storm: fever, tachycardia, agitation and altered mentation; treat with beta-blocker, thionamide, iodine after thionamide, and steroids.

Myxoedema coma: hypothermia, bradycardia, hypoventilation and reduced consciousness; give IV levothyroxine with stress-dose hydrocortisone.

SIADH: euvolaemic hyponatraemia with urine osmolality >100 mOsm/kg and urine sodium >30 mmol/L; treat with fluid restriction.

Stress hyperglycaemia in critical illness: target glucose roughly 140–180 mg/dL, avoiding hypoglycaemia.

Outcome measures: mortality, length of stay, readmission, quality-adjusted life years and patient-reported outcome measures.

QALY = survival time × health-related utility (0–1); used in cost-utility analysis.

Incremental cost-effectiveness ratio = (cost intervention − cost control)/(effect intervention − effect control); thresholds define cost-effectiveness.

Cohort studies estimate incidence and relative risk; case-control studies estimate odds ratios and suit rare outcomes.

Bias types: selection, information, confounding, and attrition; randomisation and blinding mitigate them.

Confounding can be addressed by stratification, multivariable regression, propensity scores or instrumental variables.

Number needed to harm = 1/absolute risk increase; report alongside NNT for balanced interpretation.

Benchmarking and risk adjustment are required before comparing hospital outcomes; standardised mortality ratio = observed/expected deaths.

Sepsis-3 defines sepsis as life-threatening organ dysfunction from infection, operationalised as a SOFA increase ≥2; septic shock adds vasopressor need and lactate >2 mmol/L despite fluids.

qSOFA: respiratory rate ≥22/min, altered mentation, systolic BP ≤100 mmHg; ≥2 identifies high risk outside ICU.

Blood cultures before antibiotics when this does not delay therapy; antibiotics within 1 h for septic shock and within 3 h for possible sepsis without shock.

Antimicrobial de-escalation: narrow spectrum based on culture results and clinical response; duration is often 7 days for common infections.

Ventilator-associated pneumonia: new infiltrate plus fever, purulent secretions and leukocytosis after 48 h of ventilation; sample with BAL or tracheal aspirate.

Clostridioides difficile: watery diarrhoea plus positive toxin or PCR; stop offending antibiotics and treat with oral vancomycin or fidaxomicin.

Meningococcal and influenza prophylaxis for contacts follows public health guidance; airborne precautions for tuberculosis and measles.

Therapeutic drug monitoring for vancomycin AUC/MIC and aminoglycoside troughs reduces nephrotoxicity.

Glasgow Coma Scale: eye 1–4, verbal 1–5, motor 1–6; score ≤8 generally indicates need for airway protection.

Cerebral perfusion pressure = MAP − intracranial pressure; typical CPP target 60–70 mmHg in traumatic brain injury.

Monro-Kellie doctrine: brain, blood and CSF occupy a fixed skull volume; an increase in one compartment must be offset by a decrease in another.

Intracranial hypertension: head elevation 30°, normocapnia (PaCO2 35–40 mmHg), osmotherapy with mannitol or hypertonic saline, and sedation.

Pupillary signs: fixed dilated pupil suggests uncal herniation; bilateral fixed pupils carry poor prognosis.

Status epilepticus: benzodiazepine first-line, then levetiracetam, valproate or phenytoin; refractory cases need anaesthetic doses and EEG monitoring.

Targeted temperature management after cardiac arrest: maintain 32–37.5 °C for at least 24 h, avoiding fever.

Subarachnoid haemorrhage: nimodipine reduces delayed ischaemic deficit; watch for rebleeding and hydrocephalus.

Noradrenaline is first-line vasopressor in septic shock; add vasopressin when noradrenaline dose exceeds about 0.25–0.5 µg/kg/min.

Dobutamine is an inotrope with beta-1 and mild beta-2 activity; it may cause tachycardia and hypotension from beta-2 vasodilation.

Propofol causes dose-dependent hypotension and hypertriglyceridaemia; prolonged high-dose infusion risks propofol infusion syndrome.

Midazolam is renally cleared and accumulates in renal failure; fentanyl and morphine have active metabolites, while remifentanil is organ-independent.

Aminoglycosides are concentration-dependent killers; extended-interval dosing and trough monitoring reduce toxicity.

Vancomycin requires AUC/MIC monitoring; infusion reactions (red man syndrome) are rate-related.

Heparin-induced thrombocytopenia: platelet fall >50% with thrombosis; stop heparin and start a non-heparin anticoagulant.

Cytochrome P450 interactions: CYP3A4 inhibitors (macrolides, azoles) raise levels of statins, tacrolimus and many sedatives.

Surviving Sepsis Campaign bundle: measure lactate, obtain cultures, give broad-spectrum antibiotics, start 30 mL/kg crystalloid for hypotension or lactate ≥4 mmol/L, and use vasopressors to target MAP ≥65 mmHg.

Lactate clearance is a resuscitation marker; persistently elevated lactate reflects ongoing hypoperfusion or impaired clearance.

SIRS criteria (temperature, heart rate, respiratory rate, white cell count) are sensitive but nonspecific; sepsis requires infection plus organ dysfunction.

Cytokine storm features: fever, cytopenias, hyperferritinaemia, high CRP and ferritin; consider haemophagocytic lymphohistiocytosis when criteria met.

Corticosteroids (hydrocortisone 200 mg/day) are reserved for septic shock with inadequate response to fluids and vasopressors.

Source control within 6–12 h is essential for sepsis from abscess, perforation or infected devices.

Balanced crystalloids may reduce hyperchloraemic acidosis compared with large-volume 0.9% saline.

Drotrecogin alfa and early goal-directed therapy with routine ScvO2 targets are not recommended in current practice.

KDIGO staging: stage 1 = creatinine rise ≥0.3 mg/dL within 48 h or 1.5–1.9× baseline; stage 2 = 2.0–2.9×; stage 3 = ≥3.0×, creatinine ≥4.0 mg/dL, or urine output <0.3 mL/kg/h for ≥24 h.

Urine output criteria: <0.5 mL/kg/h for 6–12 h = stage 1; ≥12 h = stage 2; ≥24 h or anuria ≥12 h = stage 3.

Prerenal vs intrinsic: fractional excretion of urea <35% suggests prerenal in patients on loop diuretics; FeNa <1% suggests prerenal when off diuretics.

Hepatorenal syndrome: cirrhosis with ascites, creatinine rise, no response to 2 days of albumin plus volume, absence of shock, no nephrotoxins, no structural renal disease; treated with terlipressin plus albumin.

Rhabdomyolysis: CK typically >5× upper limit; aggressive isotonic fluid resuscitation is the core therapy; watch for hyperkalaemia, hyperphosphataemia and hypocalcaemia.

Contrast-associated AKI risk rises with eGFR <30, diabetes, heart failure and volume depletion; use lowest contrast volume and isotonic crystalloid expansion in high-risk patients.

Renal replacement indications (AEIOU): refractory acidosis, electrolyte disturbance (hyperkalaemia), intoxication, fluid overload, uraemic complications such as pericarditis or encephalopathy.

Drug dosing: for renally cleared drugs adjust dose or interval by measured or estimated CrCl; continuous RRT affects dosing differently from intermittent haemodialysis.

Type 1 = hypoxaemic (PaO2 <60 mmHg on room air) with normal or low PaCO2; type 2 = hypercapnic with PaCO2 >50 mmHg.

Alveolar gas equation: PAO2 = FiO2 × (Patm − 47) − PaCO2/R, with R ≈ 0.8; A-a gradient distinguishes intrinsic from hypoventilation causes.

ARDS Berlin definition: onset within 1 week, bilateral opacities, not explained by cardiac failure, PEEP ≥5 cmH2O, and PaO2/FiO2 ≤300; severity mild 201–300, moderate 101–200, severe ≤100.

Lung-protective ventilation: tidal volume 6 mL/kg predicted body weight, plateau pressure ≤30 cmH2O, permissive hypercapnia and adequate PEEP.

Prone positioning for ≥16 h/day reduces mortality in moderate-severe ARDS (PaO2/FiO2 <150).

High-flow nasal oxygen typically delivers FiO2 up to 1.0 with flow 30–60 L/min and mild PEEP; ROX index (SpO2/FiO2 ÷ respiratory rate) predicts failure.

Non-invasive ventilation is first-line in acute hypercapnic COPD exacerbation with pH 7.25–7.35; avoid in unprotected airway, vomiting or facial trauma.

Recruitment manoeuvres and PEEP titration aim to reduce atelectrauma; watch for haemodynamic compromise and barotrauma.

ASA physical status: I healthy; II mild systemic disease; III severe systemic disease; IV constant threat to life; V moribund; suffix E for emergency.

RCRI (Revised Cardiac Risk Index) predictors: ischaemic heart disease, heart failure, cerebrovascular disease, insulin-treated diabetes, creatinine >2 mg/dL, and high-risk surgery (intraperitoneal, intrathoracic, suprainguinal vascular).

Mallampati classes I–IV grade oropharyngeal visibility; class III–IV predicts difficult laryngoscopy, combined with mouth opening, thyromental distance and neck mobility.

Succinylcholine is contraindicated in hyperkalaemia risk (burns, denervation, prolonged immobility) and malignant hyperthermia susceptibility; dantrolene is the antidote.

Malignant hyperthermia: rising ETCO2, masseter spasm, hyperthermia, acidosis and rhabdomyolysis; stop volatile agents, give dantrolene 2.5 mg/kg and cool.

Spinal anaesthesia causes sympathectomy-related hypotension; treat with fluids, vasopressors (phenylephrine) and left uterine displacement in obstetric patients.

Local anaesthetic systemic toxicity: stop injection, secure airway, give 20% lipid emulsion 1.5 mL/kg bolus then infusion, and avoid vasopressin, calcium channel blockers and beta-blockers.

Postoperative nausea and vomiting prophylaxis uses Apfel risk factors: female sex, non-smoker, history of PONV, and postoperative opioids.

Cardiac output = heart rate × stroke volume; stroke volume depends on preload, afterload and contractility.

Mean arterial pressure ≈ DBP + (SBP − DBP)/3; a MAP ≥65 mmHg is the usual resuscitation target in septic shock.

Frank-Starling relationship: increasing preload raises stroke volume until the plateau of the curve; dynamic indices (pulse pressure variation, SVV) predict fluid responsiveness better than static pressures.

Fick principle: CO = VO2 / (CaO2 − CvO2); thermodilution and pulse contour methods estimate CO from temperature or pressure waveforms.

Shock types: hypovolaemic, cardiogenic, distributive (septic, anaphylactic, neurogenic) and obstructive (tamponade, tension pneumothorax, pulmonary embolism).

Cardiac tamponade: Beck triad (hypotension, distended neck veins, muffled heart sounds), pulsus paradoxus, electrical alternans; treat with pericardiocentesis.

Anaphylaxis: intramuscular adrenaline 0.5 mg (0.5 mL of 1:1000) into the anterolateral thigh, repeated every 5 min; fluids and adjuncts follow.

ScvO2 <70% suggests inadequate oxygen delivery relative to demand; >80% with low CO may indicate impaired extraction or shunting.