How should you induce general anesthesia in a hypotensive septic patient on a levophed (norepinephrine) drip?

Induction of General Anesthesia in Hypotensive Septic Patients on Norepinephrine

Use ketamine as your induction agent in hypotensive septic patients on norepinephrine, and ensure the norepinephrine infusion is optimized and running through a secure central line before induction. 1

Pre-Induction Optimization

Vasopressor Management

• Confirm norepinephrine is infusing through a central venous catheter (preferably antecubital or other large vein, avoiding lower extremity access in elderly or those with vascular disease) and verify the line is patent with good blood return 2
• Target MAP ≥65 mmHg before induction using norepinephrine titration, as this is the minimum threshold to maintain autoregulation in critical vascular beds 3
• Have vasopressin 0.03 units/minute prepared and ready to add immediately if hypotension worsens during induction, as this is the recommended second-line agent 3, 4, 5
• Ensure continuous arterial blood pressure monitoring is established before induction, as this is essential for all patients requiring vasopressors 3, 4, 5

Fluid Status Assessment

• Administer at least 30 mL/kg crystalloid before or concurrent with induction if not already completed, as adequate volume resuscitation should precede or accompany vasopressor therapy 3, 5
• Do not delay induction for complete volume resuscitation if emergency airway management is required—norepinephrine can be administered as an emergency measure to maintain cerebral and coronary perfusion during concurrent resuscitation 2

Induction Agent Selection

Primary Recommendation: Ketamine

• Ketamine is the optimal induction agent because it provides the greatest hemodynamic stability through sympathetic stimulation and preservation of cardiovascular tone in shocked patients 1
• Dose: 1-2 mg/kg IV (reduce to lower end of range in profoundly hypotensive patients) 1
• Ketamine's traditional contraindication in brain injury is negated by controlled ventilation and subsequent anesthesia, which attenuate any theoretical adverse effects on intracranial pressure 1

Alternative: Etomidate (With Important Caveats)

• Etomidate (0.2-0.3 mg/kg) causes less post-intubation hypotension than ketamine in septic patients (50% vs 74% incidence), but this must be weighed against adrenal suppression concerns 6
• Etomidate suppresses adrenal steroidogenesis, though clinical consequences remain unclear and evidence of harm is inconsistent when adjusted for illness severity 7
• Consider etomidate only if ketamine is unavailable or if the patient has severe cardiovascular instability where even ketamine's minimal cardiovascular depression is unacceptable 7, 6

Intra-Induction Vasopressor Management

Immediate Response Protocol

• Increase norepinephrine dose by 25-50% immediately before induction to preemptively counteract the vasodilation and myocardial depression from positive pressure ventilation and residual anesthetic effects 8
• If MAP drops below 65 mmHg despite increased norepinephrine, immediately add vasopressin 0.03 units/minute rather than escalating norepinephrine further, as this acts on different vascular receptors and has norepinephrine-sparing effects 3, 4
• If MAP remains <65 mmHg with norepinephrine plus vasopressin, add epinephrine 0.1-0.5 mcg/kg/min as the third-line agent 3

Agents to Avoid

• Never use dopamine as it is associated with higher mortality and more arrhythmias compared to norepinephrine, with no benefit in organ dysfunction 3, 5
• Avoid phenylephrine except as salvage therapy, as it may raise blood pressure numbers while actually worsening tissue perfusion through excessive vasoconstriction without cardiac output support 3, 4
• Do not use low-dose dopamine for "renal protection"—this is strongly discouraged and provides no benefit 3, 5

Post-Intubation Management

Immediate Assessment

• Monitor for signs of inadequate perfusion beyond just MAP: rising lactate, decreased urine output, worsening mental status, or digital ischemia from excessive vasoconstriction 3, 4
• Titrate vasopressors to maintain MAP 65 mmHg while monitoring perfusion markers, not to supranormal blood pressure targets 3

Refractory Hypotension Protocol

• If shock remains refractory despite norepinephrine plus vasopressin, add dobutamine 5-20 mcg/kg/min if myocardial dysfunction is evident, rather than escalating vasopressors further 3, 4, 5
• Continue aggressive fluid resuscitation using dynamic variables (pulse pressure variation, stroke volume variation) to guide therapy, as occult hypovolemia should always be suspected in refractory shock 3

Critical Pitfalls to Avoid

• Never induce without securing central venous access for norepinephrine, as peripheral extravasation causes tissue necrosis and the drug must be given centrally 3, 2
• Do not mix norepinephrine with sodium bicarbonate or alkaline solutions in the IV line, as adrenergic agents are inactivated in alkaline solutions 3
• Avoid using leg veins for norepinephrine infusion in elderly patients or those with vascular disease, as gangrene has been reported 2
• Never abruptly discontinue norepinephrine—reduce gradually once hemodynamic stability is achieved 2
• Do not use etomidate and ketamine together—choose one induction agent based on the clinical scenario 6