Intraoperative Anesthesia Management
Intraoperative management
Induction may be IV, inhalational, or intramuscular. Prepare equipment, suction, oxygen, and rescue drugs before induction. Airway management follows a planned strategy: preoxygenate, assess aspiration risk, choose a supraglottic airway or endotracheal tube, and confirm placement with sustained capnography. Maintenance uses volatile agents, IV anesthetics, opioids, and muscle relaxants titrated to surgical stimulus. Ventilation aims to maintain oxygenation and normocapnia while protecting lungs with appropriate tidal volumes and pressures. Fluid therapy replaces deficits and losses; blood products are guided by bleeding, hemoglobin, coagulation, and physiology, not a single number.
Hypotension has multiple causes: hypovolemia, vasodilation, myocardial depression, anaphylaxis, pneumothorax, high neuraxial block, and surgical compression. Treat the cause before reflexively giving pressors. Sudden desaturation requires a systematic check: oxygen supply, circuit, tube position, breath sounds, end-tidal CO2, and hemodynamics. Malignant hyperthermia presents with hypercarbia, rigidity, tachycardia, and rising temperature; stop triggering agents, give dantrolene, hyperventilate with 100% oxygen, and cool. Local anesthetic systemic toxicity can cause seizures and cardiovascular collapse; support the airway, give lipid emulsion, and avoid vasopressin.
Traps and a rule
Traps include assuming a normal blood pressure excludes shock, treating every high peak pressure as bronchospasm, and delaying dantrolene. Another is using a fixed tidal volume without considering obesity or lung disease.
Rule of thumb: for a sudden fall in end-tidal CO2 with hypotension, think pulmonary embolism, hypovolemia, or cardiac arrest; for a sudden rise in end-tidal CO2 with tachycardia and fever, consider malignant hyperthermia and act immediately.