C-AA cheat sheet

MAC is the minimum alveolar concentration at 1 atmosphere that prevents movement in 50% of subjects given a standardized noxious stimulus; MAC-awake is about 0.3–0.4 MAC.

Approximate MAC values: sevoflurane 2%, isoflurane 1.15%, desflurane 6%, nitrous oxide 104%; MAC decreases with age, hypothermia, pregnancy, and opioid or sedative coadministration.

CaO2 = (1.34 × Hb × SaO2) + (0.003 × PaO2); oxygen delivery = cardiac output × CaO2 × 10.

Henderson–Hasselbalch: pH = 6.1 + log([HCO3−] / (0.03 × PaCO2)).

Propofol and etomidate act at GABA-A receptors; ketamine antagonizes NMDA receptors; dexmedetomidine is an alpha-2 agonist; naloxone antagonizes mu-opioid receptors.

Nondepolarizing neuromuscular blockers competitively antagonize acetylcholine at nicotinic receptors; succinylcholine is a depolarizing blocker resistant to acetylcholinesterase.

Context-sensitive half-time is the time for plasma concentration to decline by 50% after an infusion stops; it lengthens with longer infusions for lipophilic drugs.

Fick principle: oxygen consumption = cardiac output × (arterial O2 content − mixed venous O2 content).

Pulse oximetry uses spectrophotometry at red and infrared wavelengths; it is less reliable with motion, poor perfusion, methemoglobin, carboxyhemoglobin, and nail polish.

Carboxyhemoglobin produces falsely high SpO2 because its absorption resembles oxyhemoglobin at 660 nm; methemoglobin drives SpO2 toward about 85%.

Capnography: sudden EtCO2 to zero suggests disconnection, esophageal intubation, complete obstruction, or cardiac arrest; a gradual rise suggests hypoventilation, fever, or sepsis.

Normal EtCO2 is 35–45 mmHg; the capnogram has phases for dead space, ascending alveolar gas, alveolar plateau, and inspiration.

Variable-bypass vaporizers are agent-specific, temperature-compensated, and interlocked; desflurane requires a heated, pressurized vaporizer.

Pipeline gas is supplied near 50 psi; a full oxygen cylinder reads about 2,200 psi; cylinder pressure falls proportionally to remaining volume.

NIBP cuff bladder width should be about 40% of arm circumference; too narrow a cuff overestimates blood pressure.

Anesthesia machine check sequence includes high-pressure system, low-pressure system, breathing circuit, scavenging system, and ventilation delivery.

ASA I: healthy; II: mild systemic disease; III: severe systemic disease; IV: constant threat to life; V: moribund; VI: brain-dead organ donor; E suffix denotes emergency.

Mallampati I: soft palate, uvula, fauces, pillars; II: soft palate, uvula, fauces; III: soft palate and base of uvula; IV: hard palate only.

Airway predictors: mouth opening <3 cm, thyromental distance <6 cm, Mallampati III–IV, limited neck extension, short thick neck, and inability to protrude mandible.

NPO: clear fluids 2 h, breast milk 4 h, infant formula 6 h, nonhuman milk 6 h, light meal 6 h, fatty meal 8 h.

RCRI includes ischemic heart disease, heart failure, cerebrovascular disease, insulin-treated diabetes, creatinine >2 mg/dL, and high-risk surgery; ≥3 factors indicates elevated risk.

Routine preoperative testing is not indicated for low-risk surgery in asymptomatic patients; tests are selected by history, comorbidity, and procedure risk.

Informed consent requires capacity, disclosure, understanding, voluntariness, and authorization; emergency treatment may proceed under implied consent when delay is dangerous.

Induction doses: propofol 1.5–2.5 mg/kg, etomidate 0.2–0.3 mg/kg, ketamine 1–2 mg/kg, succinylcholine 1–1.5 mg/kg, rocuronium 0.6–1.2 mg/kg.

Rapid sequence intubation uses a rapidly acting induction agent and neuromuscular blocker; confirm tube placement with continuous capnography.

Lung-protective ventilation: tidal volume 6–8 mL/kg predicted body weight, PEEP 5 cmH2O, plateau pressure <30 cmH2O, and permissive hypercapnia when appropriate.

Malignant hyperthermia: stop triggers, 100% O2, dantrolene 2.5 mg/kg IV, active cooling, treat hyperkalemia and acidosis; avoid calcium channel blockers with dantrolene.

LAST: stop injection, call for help, airway and oxygen, 20% lipid emulsion 1.5 mL/kg bolus then 0.25 mL/kg/min; avoid vasopressin and calcium channel blockers.

Train-of-four ratio >0.9 indicates adequate reversal; sugammadex reverses rocuronium and vecuronium by encapsulation.

Intraoperative hypotension treatment includes volatile reduction, fluid bolus, and vasopressors; choice depends on volume status, cardiac function, and cause.

Transfusion: one unit packed red blood cells raises hemoglobin about 1 g/dL in adults; check and treat hypocalcemia with massive transfusion.

Aldrete score assesses activity, respiration, circulation, consciousness, and oxygen saturation; score ≥9 with stable vitals commonly permits phase I discharge.

Apfel PONV factors: female sex, nonsmoking, history of PONV or motion sickness, and postoperative opioids; score 0–4 guides prophylaxis.

PONV prophylaxis options include ondansetron, dexamethasone, droperidol, and scopolamine; multimodal therapy is used for elevated risk.

Atelectasis is the most common postoperative respiratory complication; incentive spirometry, early ambulation, and adequate analgesia reduce it.

Anaphylaxis: epinephrine 0.1–0.5 mg IM (1:1,000) in adults, oxygen, fluids, and removal of trigger; antihistamines and steroids are adjuncts.

Postoperative hypotension causes include hypovolemia, bleeding, residual anesthesia, sepsis, myocardial infarction, and adrenal insufficiency.

Handoff should include procedure, airway, medications, fluids, blood loss, vital trends, lines, allergies, and pending issues.

Professional practice: never events include wrong-site surgery, retained foreign body, and medication error; reporting and root-cause analysis are required.