Egyptian Board Anesthesia cheat sheet

Oxygen content: CaO2 = (1.34 × Hb × SaO2) + (0.003 × PaO2); at Hb 15 g/dL and SaO2 100%, dissolved O2 contributes only ~0.3 mL/dL of ~20 mL/dL total.

Henderson–Hasselbalch: pH = 6.1 + log([HCO3-]/(0.03 × PaCO2)); acute rise in PaCO2 of 10 mmHg lowers pH by ~0.08, chronic rise by ~0.03 via renal compensation.

Alveolar gas equation: PAO2 = FiO2 × (Patm − 47) − PaCO2/R, with R ≈ 0.8; at sea level on room air PAO2 ≈ 100 mmHg.

Volume of distribution determines loading dose (Vd = Dose/C0); clearance determines maintenance rate (Cl = k × Vd); context-sensitive half-time rises with prolonged infusion for lipophilic drugs such as thiopental and fentanyl.

Minimum alveolar concentration (MAC) is reduced by ~25–30% per decade above age 40, and by hypothermia, pregnancy, opioids, and IV anesthetics; MAC is not altered by duration of anesthesia.

Ionized calcium is the physiologically active fraction (~1.2 mmol/L); it falls with alkalosis and citrate transfusion, while total calcium falls with hypoalbuminemia without changing ionized levels.

Poiseuille's law: flow ∝ r⁴/length and ∝ ΔP/viscosity; halving catheter radius reduces flow 16-fold, so resistance rises with narrow, long, low-viscosity-independent tubing.

Nerve fibers: A-alpha (motor/proprioception, fastest), A-delta (sharp pain, cold), B (preganglionic autonomic, most susceptible to local anesthetics), C (dull pain, warm, slowest).

Oxygen delivery DO2 = CO × CaO2 × 10; critical DO2 in adults is roughly 300–330 mL/min/m², below which VO2 becomes supply-dependent.

Revised Cardiac Risk Index (RCRI) predictors: ischemic heart disease, heart failure, cerebrovascular disease, insulin-treated diabetes, creatinine >2 mg/dL, and high-risk surgery; ≥3 predictors indicates elevated major adverse cardiac event risk.

ACC/AHA framework: assess procedural risk (low <1%, elevated ≥1%), then functional capacity in METs; ≥4 METs generally permits surgery without further cardiac testing.

Stop smoking at least 4 weeks preoperatively for maximal respiratory benefit; carboxyhemoglobin half-life is ~4–6 hours on room air and ~40 minutes on high-flow oxygen.

Perioperative beta-blockade should be started days to weeks before surgery at low dose and titrated; abrupt initiation on the day of surgery increases stroke and mortality.

Dual antiplatelet therapy after coronary stenting: delay elective surgery ≥30 days after bare-metal stent and ≥6 months after drug-eluting stent if P2Y12 inhibition must be interrupted.

Child–Pugh and MELD scores predict perioperative mortality in cirrhosis; MELD >15 and Child class C carry substantially increased risk for elective nonhepatic surgery.

STOP-BANG ≥3 indicates high obstructive sleep apnea risk: snoring, tiredness, observed apnea, pressure, BMI >35, age >50, neck circumference >40 cm, male sex.

Anemia (Hb <13 g/dL in men, <12 g/dL in women) independently predicts perioperative morbidity; treat iron deficiency before elective surgery rather than transfusing empirically.

Fasting intervals per ASA: clear fluids 2 hours, breast milk 4 hours, infant formula and nonhuman milk 6 hours, light meal 6 hours, fatty meal 8 hours.

Difficult airway prediction: Mallampati 3–4, thyromental distance <6 cm, mouth opening <3 cm, neck circumference >43 cm, and limited cervical extension each raise risk; no single test is sensitive.

ASA difficult airway algorithm: after failed mask ventilation and failed supraglottic airway, proceed to emergency invasive airway (cricothyrotomy) after a maximum of three intubation attempts with optimized technique.

Rapid sequence induction uses a rapidly acting induction agent plus succinylcholine 1–1.5 mg/kg (or rocuronium 1.2 mg/kg) with cricoid pressure and no interposed ventilation.

Succinylcholine is contraindicated in hyperkalemia, burns and denervation beyond 48–72 hours, spinal cord injury, malignant hyperthermia susceptibility, and pseudocholinesterase deficiency.

Sugammadex 16 mg/kg reverses rocuronium deep block; 2 mg/kg reverses train-of-four count ≥2, and 4 mg/kg reverses post-tetanic count 1–2.

Malignant hyperthermia: dantrolene 2.5 mg/kg IV repeated to 10 mg/kg, stop triggering agents, hyperventilate with 100% O2, and treat hyperkalemia and acidosis.

Laryngeal mask airway cuff should be inflated to just seal at ~20–30 cmH2O; leak pressure below 20 cmH2O predicts inadequate seal for positive pressure ventilation.

End-tidal CO2 waveform loss with a patent airway suggests esophageal intubation, disconnection, or cardiac arrest; sustained low ETCO2 with normal ventilation suggests pulmonary embolism or low cardiac output.

Depth of anesthesia: BIS 40–60 is the usual target; end-tidal volatile concentration of 0.7–1.3 MAC prevents awareness in most adults, and higher concentrations are needed in younger patients.

Maximum local anesthetic doses (adult, without epinephrine): lidocaine 4.5 mg/kg (7 mg/kg with epinephrine), bupivacaine 2.5 mg/kg (3 mg/kg), ropivacaine 3 mg/kg, levobupivacaine 2.5 mg/kg.

Local anesthetic systemic toxicity: stop injection, secure airway with 100% O2, give 20% lipid emulsion 1.5 mL/kg bolus then 0.25 mL/kg/min infusion, and avoid vasopressin, calcium channel blockers, and beta-blockers.

Spinal anesthesia block height: hyperbaric bupivacaine spreads with gravity; sitting position limits cephalad spread, and a T4 level is needed for cesarean delivery.

Post-dural puncture headache: occurs in 0.5–1% with 25–27G pencil-point needles; conservative therapy first, then epidural blood patch of 15–20 mL autologous blood.

Interscalene brachial plexus block reliably anesthetizes C5–C7 but spares the ulnar (C8–T1) distribution; phrenic nerve block occurs in nearly all patients and is risky in severe pulmonary disease.

Adductor canal block spares the femoral nerve's motor branches to the quadriceps while providing medial knee analgesia; it is preferred over femoral block for same-day knee arthroplasty.

Epidural test dose: 3 mL of lidocaine 1.5% with epinephrine 1:200,000; a rise in heart rate >20 bpm or systolic pressure >15–20 mmHg suggests intravascular placement.

Transversus abdominis plane block covers T10–L1 somatic abdominal wall pain but not visceral pain; rectus sheath block covers midline incisions at similar dermatomes.

Anticoagulation and neuraxial blocks: stop prophylactic low-molecular-weight heparin 12 hours before, therapeutic LMWH 24 hours before, and wait 4–6 hours after catheter removal before redosing.

Cesarean delivery under spinal anesthesia: 0.75% hyperbaric bupivacaine 10–12 mg plus opioid; treat hypotension with phenylephrine infusion 25–50 mcg/min and left uterine displacement.

One-lung ventilation: use a double-lumen tube sized 35–41 Fr by sex and height, confirm with fiberoptic bronchoscopy, and target tidal volume 4–6 mL/kg predicted body weight with PEEP 5 cmH2O.

Cardiac surgery: cardiopulmonary bypass primes with crystalloid, causes hemodilution and a fall in oncotic pressure; heparin 300–400 units/kg targets ACT >400–480 seconds.

Neuroanesthesia: maintain cerebral perfusion pressure = MAP − ICP at 60–70 mmHg; hyperventilation to PaCO2 30–35 mmHg reduces ICP by cerebral vasoconstriction.

Pediatric anesthesia: laryngospasm is most common at 2–5 years; treat with 100% O2, continuous positive airway pressure, deepening anesthesia, and succinylcholine 0.5–1 mg/kg IV if needed.

Pediatric fluid: 4-2-1 rule for hourly maintenance (4 mL/kg for first 10 kg, 2 mL/kg for next 10 kg, 1 mL/kg thereafter); blood volume is ~80 mL/kg in neonates, 70 mL/kg in infants.

Urologic anesthesia: transurethral resection of prostate syndrome causes dilutional hyponatremia from glycine absorption; treat with hypertonic saline only if sodium <120 mmol/L or symptoms are severe.

Orthopedic anesthesia: use hypotensive anesthesia to reduce surgical bleeding; tourniquet pain begins after 45–60 minutes and is treated by inflating to 250–300 mmHg or releasing the tourniquet.

Obstetric hemorrhage: oxytocin 5 units slow IV plus infusion, then carboprost 250 mcg intramuscularly every 15 minutes up to 2 mg; avoid carboprost in asthma.

ARDS Berlin definition: acute onset within 1 week, bilateral opacities, PaO2/FiO2 ≤300 mmHg on PEEP ≥5 cmH2O, not fully explained by cardiac failure; tidal volume 6 mL/kg predicted body weight.

Sepsis-3: suspected infection plus SOFA increase ≥2; septic shock is vasopressor requirement to maintain MAP ≥65 mmHg with lactate >2 mmol/L despite adequate fluid resuscitation.

Sepsis fluid resuscitation: 30 mL/kg crystalloid within the first 3 hours; norepinephrine is first-line vasopressor, with vasopressin or epinephrine added for refractory shock.

Mechanical ventilation: plateau pressure <30 cmH2O, driving pressure <15 cmH2O, and permissive hypercapnia with pH ≥7.20 in severe ARDS.

Acute kidney injury KDIGO stages: stage 1 = creatinine rise ≥0.3 mg/dL in 48 hours or 1.5–1.9× baseline; stage 3 = 3× baseline or creatinine ≥4 mg/dL or dialysis initiation.

Sodium correction: limit to 8–10 mmol/L per 24 hours to avoid osmotic demyelination; correct rapidly only in severe symptomatic hyponatremia with seizures or coma.

Vasopressor dosing: norepinephrine 0.01–3 mcg/kg/min, vasopressin 0.03 units/min fixed, epinephrine 0.01–0.5 mcg/kg/min; norepinephrine is preferred over dopamine in septic shock.

Delirium in ICU: use the CAM-ICU; nonpharmacologic measures first, dexmedetomidine 0.2–1.5 mcg/kg/h is favored over benzodiazepines for agitated delirium.

Transfusion threshold in critically ill adults: restrictive strategy (Hb <7 g/dL) is noninferior to liberal (Hb <9 g/dL), except in active ischemic heart disease where <8 g/dL is used.

Neuropathic pain first-line agents: gabapentin, pregabalin, duloxetine, and tricyclic antidepressants; opioids are not first-line for neuropathic pain.

Opioid conversion: oral morphine 30 mg ≈ oral oxycodone 20 mg ≈ oral hydromorphone 6 mg ≈ transdermal fentanyl 12 mcg/h; reduce calculated equianalgesic dose by 25–50% for incomplete cross-tolerance.

Tramadol and tapentadol lower seizure threshold and cause serotonin syndrome with SSRIs; avoid in epilepsy and with monoamine oxidase inhibitors.

Cancer pain ladder: nonopioid for mild pain, weak opioid for moderate, strong opioid for severe; adjuvant drugs treat neuropathic and bone pain at any step.

Palliative dyspnea: opioids reduce the sensation of breathlessness; supplemental oxygen helps only if hypoxemic; midazolam treats terminal restlessness.

Naloxone for opioid overdose: 0.04–0.4 mg IV titrated every 2–3 minutes; use small doses in opioid-tolerant patients to avoid withdrawal and pain crisis.

Complex regional pain syndrome: sympathetic block and physical therapy for type I; diagnosis requires disproportionate pain, sensory, vasomotor, and sudomotor changes without nerve injury.

Steroid epidural injection: methylprednisolone 40–80 mg or triamcinolone 40 mg; repeat no more than 3–4 times per year and avoid in uncontrolled diabetes or systemic infection.

Palliative sedation: used for refractory symptoms at end of life with informed consent; midazolam infusion 0.5–2 mg/h titrated to comfort, with hydration decisions made explicitly.

WHO surgical safety checklist has three phases: sign-in before induction, time-out before incision, and sign-out before leaving the operating room.

Critical incident reporting must be nonpunitive and confidential; report within 24 hours and use root cause analysis for severe events such as wrong-site surgery.

Informed consent requires capacity, disclosure of material risks, benefits, and alternatives, and voluntariness; the standard is what a reasonable patient would want to know.

Do-not-resuscitate orders in the operating room require explicit discussion: some orders are suspended for the procedure, while others are continued with defined limits.

Medication error prevention: standardize concentrations, use color-coded labels, double-check high-alert drugs, and read back verbal orders to confirm accuracy.

Wrong-site surgery prevention: preoperative marking by the surgeon, verification of site with the patient when possible, and a formal time-out with all team members present.

Quality metrics: anesthesia-related mortality is roughly 1 in 100,000 to 1 in 200,000 anesthetics; reportable events include unanticipated difficult intubation and awareness.

Confidentiality: disclose patient information only to those involved in care; breaches include discussing cases in public areas and unsecured electronic records.

Duty of candor: after a harmful event, disclose to the patient or family promptly, explain what happened, apologize, and describe corrective actions.

Adult cardiac arrest: compressions at 100–120/min, depth 5–6 cm, full recoil, minimize interruptions; ratio 30:2 without advanced airway, then continuous compressions with 1 breath every 6 seconds.

Defibrillation: biphasic 120–200 J for shockable rhythms; resume compressions immediately after shock and check rhythm every 2 minutes; epinephrine 1 mg every 3–5 minutes.

Trauma primary survey: airway with cervical spine protection, breathing, circulation with hemorrhage control, disability, exposure; massive transfusion protocol 1:1:1 ratio of red cells, plasma, platelets.

Hemorrhagic shock: permissive hypotension to systolic 80–90 mmHg until hemorrhage is controlled, except in traumatic brain injury where MAP ≥80 mmHg is targeted.

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

Anaphylaxis: epinephrine 0.3–0.5 mg intramuscularly (1:1000) in the anterolateral thigh, repeat every 5–15 minutes; give fluids and adjuncts after epinephrine.

Local anesthetic toxicity: lipid emulsion 20% at 1.5 mL/kg bolus, then 0.25 mL/kg/min; continue for at least 15 minutes after circulatory stability.

Massive hemorrhage: tranexamic acid 1 g IV over 10 minutes within 3 hours of injury, then 1 g over 8 hours; calcium replacement is needed with citrate-containing blood products.

Difficult mask ventilation with oxygen desaturation: call for help, optimize head position, use two-person technique, insert oral or nasal airway, and consider supraglottic rescue.