PGIM MD Anaesthesiology cheat sheet

Mallampati class III–IV, thyromental distance <6 cm, mouth opening <3 cm, and limited neck extension each independently predict difficult laryngoscopy; no single test has high sensitivity.

Difficult mask ventilation predictors (MOANS): Mask seal poor, Obesity/Obstruction, Age >55, No teeth, Stiff lungs; difficult supraglottic rescue (RODS): Restricted opening, Obstruction, Disrupted airway, Stiff lungs.

Cannot intubate cannot oxygenate (CICO): declare early, call for help, and proceed to emergency front-of-neck access (scalpel-bougie-tube or cannula techniques) rather than repeated intubation attempts.

Rapid sequence induction: preoxygenate 3–5 min to end-tidal O2 >90%, give hypnotic plus neuromuscular blocker, apply cricoid force only if aspiration risk is high, and intubate without bag-mask ventilation unless desaturation occurs.

Suxamethonium 1–1.5 mg/kg gives intubating conditions in 45–60 s and lasts 5–10 min; rocuronium 1.2 mg/kg gives similar conditions in 60 s and is reversible with sugammadex 16 mg/kg.

Confirm tracheal tube position with continuous waveform capnography plus auscultation; sustained absence of end-tidal CO2 mandates tube repositioning or removal, not reassurance.

Laryngospasm: remove stimulus, apply 100% oxygen with CPAP and jaw thrust, deepen anaesthesia; if persistent give propofol 0.5–1 mg/kg or suxamethonium 0.5–1 mg/kg IV (or 4 mg/kg IM).

Depth monitoring: age-adjusted MAC ~1.0 prevents awareness in most adults; BIS 40–60 is used when volatile agent is avoided, and processed EEG is recommended for paralysis with total intravenous anaesthesia.

Maximum local anaesthetic doses (adult, without adrenaline): lidocaine 3 mg/kg, bupivacaine 2 mg/kg, ropivacaine 3 mg/kg, levobupivacaine 2 mg/kg; adding adrenaline raises lidocaine to 7 mg/kg.

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

Spinal anaesthesia block height depends on baricity and patient position: hyperbaric bupivacaine settles with gravity, so sitting position limits spread and Trendelenburg raises it.

Spinal-induced hypotension: treat with left uterine displacement, fluid, and phenylephrine 50–100 mcg boluses or infusion; avoid pure vasoconstrictors in obstetric patients with pre-eclampsia-related cardiac dysfunction.

Adrenaline-containing test dose for epidural: 15 mcg adrenaline produces a rise in heart rate within 20–40 s if intravascular; aspiration alone is unreliable.

Post-dural puncture headache: conservative therapy first, then epidural blood patch 15–20 mL autologous blood at the level of the puncture, effective in about 70–90% after one patch.

Acute pain ladder per WHO: paracetamol plus NSAID as base, then weak opioid, then strong opioid; multimodal analgesia reduces opioid dose and adverse effects.

Neuropathic pain: first-line gabapentinoids (gabapentin, pregabalin), tricyclics (amitriptyline), or duloxetine; opioids are not first-line for chronic neuropathic pain.

Sepsis-3: suspect infection plus SOFA increase ≥2; septic shock requires vasopressor need to maintain MAP ≥65 mmHg and lactate >2 mmol/L despite adequate fluid resuscitation.

Surviving Sepsis hour-1 bundle: measure lactate, obtain blood cultures before antibiotics, give broad-spectrum antibiotics, begin 30 mL/kg crystalloid for hypotension or lactate ≥4, and start vasopressors for MAP <65.

ARDS Berlin definition: acute onset within 1 week, bilateral opacities not fully explained by effusion/collapse/nodule, not primarily cardiac, PaO2/FiO2 ≤300 with PEEP ≥5; lung-protective tidal volume 6 mL/kg predicted body weight and plateau pressure ≤30 cmH2O.

Ventilator weaning: rapid shallow breathing index (respiratory rate/tidal volume in litres) <105 predicts extubation success; perform spontaneous breathing trial for 30–120 min.

Acute kidney injury KDIGO staging: stage 1 creatinine 1.5–1.9× baseline or urine <0.5 mL/kg/h for 6–12 h; stage 3 creatinine ≥3× baseline or ≥353.6 micromol/L or dialysis.

Hyperkalaemia with ECG changes: give IV calcium gluconate 10% 10–30 mL for membrane stabilisation, then insulin 10 units with 25 g glucose, then salbutamol; dialysis for refractory cases.

Delirium in ICU: use CAM-ICU for screening; non-pharmacological measures first, avoid benzodiazepines, and use dexmedetomidine or antipsychotics only for distressing symptoms.

Brain death testing prerequisites: known cause, core temperature >36 °C, systolic BP >100 mmHg, no sedatives or neuromuscular blockers, and exclusion of metabolic or endocrine confounders before formal apnoea testing.

Oxygen delivery DO2 = cardiac output × arterial oxygen content (CaO2 = 1.34 × Hb × SaO2 + 0.003 × PaO2); normal ~1000 mL/min, consumption ~250 mL/min, extraction ratio ~25%.

Alveolar gas equation: PAO2 = FiO2 × (Patm − 47) − PaCO2/0.8; at sea level with FiO2 0.21 and PaCO2 5.3 kPa, PAO2 is roughly 13.3 kPa.

Oxyhaemoglobin dissociation curve shifts right (reduced affinity) with increased temperature, CO2, 2,3-DPG, and acidosis; fetal haemoglobin and carboxyhaemoglobin shift it left.

Frank-Starling: stroke volume rises with preload until the plateau; dynamic indices (pulse pressure variation >13%, stroke volume variation) predict fluid responsiveness better than CVP.

Cerebral blood flow is ~50 mL/100 g/min and is autoregulated between MAP 60–160 mmHg; it rises ~4% per mmHg PaCO2 change in the 20–80 mmHg range.

Renal blood flow is ~20% of cardiac output; GFR ~125 mL/min; autoregulation holds renal flow between MAP 80–180 mmHg.

Lung compliance normal ~100 mL/cmH2O (or 60–70 mL/cmH2O in ventilated patients); airway resistance normal ~2 cmH2O/L/s; functional residual capacity ~30 mL/kg.

Closing capacity exceeds functional residual capacity in supine adults around age 45 and in infants, promoting airway closure and shunt during anaesthesia.

Propofol induction 1.5–2.5 mg/kg IV; onset 30–60 s; context-sensitive half-time rises only modestly with infusion duration; causes hypotension and apnoea, and supports antiemetic effect at low dose.

Ketamine 1–2 mg/kg IV provides dissociative anaesthesia with analgesia and preserved airway reflexes; increases heart rate, blood pressure and secretions; contraindicated in uncontrolled hypertension and raised intracranial pressure with poor compliance.

Volatile agents: MAC values approximately sevoflurane 2.0%, isoflurane 1.15%, desflurane 6.0%; MAC is reduced by pregnancy, hypothermia, opioids, and increasing age (~6% per decade over 40).

Neuromuscular blockers: depolarising suxamethonium is hydrolysed by plasma cholinesterase; non-depolarising agents (rocuronium, vecuronium, atracurium) are reversed by neostigmine 0.04–0.07 mg/kg with glycopyrrolate, or sugammadex for aminosteroids.

Pharmacokinetics: volume of distribution Vd = dose/plasma concentration; clearance CL = rate of elimination/plasma concentration; half-life t½ = 0.693 × Vd/CL.

Physics: Hagen-Poiseuille flow Q = πr⁴ΔP/(8ηL) explains why halving tube radius cuts flow 16-fold; turbulent flow follows Reynolds number >2000.

Gas laws: Boyle (PV constant at fixed T), Charles (V/T constant at fixed P), Dalton (total pressure = sum of partial pressures), Henry (dissolved gas proportional to partial pressure).

Monitoring: pulse oximetry uses two wavelengths (660 and 940 nm) and is unreliable with carboxyhaemoglobin, methaemoglobin, poor perfusion and motion; capnography is the standard for tube confirmation.

One-lung ventilation: use protective tidal volume 4–6 mL/kg predicted body weight, PEEP 5 cmH2O to the dependent lung, and limit plateau pressure <25–30 cmH2O; treat hypoxaemia by checking tube position, applying CPAP to the non-dependent lung, or intermittent two-lung ventilation.

Carotid endarterectomy: maintain MAP at or above baseline to preserve cerebral perfusion; regional cervical plexus block allows awake neurological monitoring; avoid hypotension and hypercarbia.

Major abdominal surgery: consider epidural or transversus abdominis plane block for analgesia; maintain normothermia and euvolemia; goal-directed fluid therapy reduces ileus.

Neurosurgery: maintain PaCO2 4.5–5.0 kPa (normocapnia) and avoid hypotension; mannitol 0.25–1 g/kg or hypertonic saline reduces brain bulk; head-up 15–30° improves venous drainage.

Cardiac surgery: cardiopulmonary bypass causes systemic inflammatory response, coagulopathy and platelet dysfunction; heparin is reversed with protamine 1 mg per 100 units heparin.

Bariatric surgery: use opioid-sparing multimodal analgesia, lung-protective ventilation, and ramped position for induction; drug dosing by lean body weight for most agents except suxamethonium and neostigmine.

Liver transplantation: reperfusion syndrome causes hypotension, hyperkalaemia, acidosis and arrhythmias; treat with calcium, bicarbonate, vasopressors and volume, and monitor for fibrinolysis.

Day-case surgery: criteria for discharge include stable vital signs, no nausea or pain, ability to walk and void, and a responsible escort; PONV prophylaxis with ondansetron plus dexamethasone reduces risk.

Neuraxial block in labour: spinal or epidural; watch for hypotension, treat with left uterine displacement, fluids and phenylephrine; test sensory level before allowing mobilisation.

Pre-eclampsia: severe features include BP ≥160/110 mmHg, platelets <100 ×10⁹/L, creatinine >97 micromol/L, liver enzymes twice normal, pulmonary oedema, and visual or cerebral symptoms; magnesium sulphate 4 g loading then 1 g/h prevents eclampsia.

Obstetric haemorrhage: activate massive transfusion protocol, give tranexamic acid 1 g within 3 h of birth, and use oxytocin, ergometrine, carboprost and misoprostol in sequence for uterine atony.

Neonatal resuscitation: dry and stimulate, assess tone and breathing; if apnoeic or HR <100 give positive pressure ventilation at 40–60/min; chest compressions 3:1 with ventilation if HR <60 after effective ventilation.

Paediatric airway: large head, short neck, large tongue, anterior larynx, and narrowest point at the cricoid ring; use uncuffed or cuffed tube sized by age/4 + 4 (uncuffed) or age/4 + 3.5 (cuffed).

Paediatric fluids: 4-2-1 rule for maintenance (4 mL/kg/h for first 10 kg, 2 for next 10, 1 thereafter); use isotonic crystalloid with glucose avoidance unless hypoglycaemia.

Paediatric drug doses: suxamethonium 2 mg/kg IV in infants, 1–2 mg/kg in children; atropine 20 mcg/kg premedication to prevent bradycardia; paracetamol 15 mg/kg.

Paediatric anaesthesia risks: laryngospasm, bradycardia from hypoxia, and postoperative apnoea in ex-premature infants under 60 weeks postmenstrual age; monitor with apnoea alarms.