Is ketamine a concern in patients with severe sepsis?

Ketamine is NOT a concern in severe sepsis—it is actually the PREFERRED sedative agent for intubation and ongoing sedation in septic shock

Ketamine should be your first-choice sedative for intubation and procedural sedation in patients with severe sepsis or septic shock because it maintains cardiovascular stability while other agents cause dangerous hypotension. 1

Why Ketamine is Preferred in Septic Shock

Hemodynamic Advantages

• Ketamine preserves cardiovascular stability through endogenous catecholamine release and avoids the myocardial depression caused by propofol, benzodiazepines, and other traditional sedatives. 1
• The American College of Critical Care Medicine specifically recommends ketamine with atropine premedication for sedation and intubation in pediatric septic shock, a principle that extends to adult practice due to shared hemodynamic concerns. 1
• Ketamine is the only intravenous anesthetic that increases mean arterial pressure without compromising cardiac output, primarily through sympathetic nervous system stimulation. 2

Clinical Evidence Supporting Use

• In a randomized controlled trial comparing ketamine-based versus fentanyl-based regimens for intubation in septic shock patients, the ketamine group demonstrated higher mean arterial pressure at 1,2, and 5 minutes post-induction, with significantly lower incidence of post-intubation hypotension (47.8% versus 84.2%, P=0.014). 3
• When combined with lidocaine (0.5 mg/kg ketamine plus 1 mg/kg lidocaine), the incidence of post-intubation hypotension was even lower at only 5% compared to 77% with ketamine full-dose alone. 4

Specific Dosing Protocol

For Intubation

• Administer 1-2 mg/kg IV ketamine bolus with atropine premedication to prevent secretions and bradycardia. 1
• Co-administer with an intravenous benzodiazepine (e.g., midazolam 0.05 mg/kg) to reduce emergence reactions. 1, 5

For Continuous Sedation

• Ketamine can be used as a continuous infusion (0.3 mg/kg/hr) to maintain cardiovascular stability during mechanical ventilation in septic shock. 1, 6
• Low-dose continuous ketamine infusion (0.3 mg/kg/hr) in septic shock patients demonstrated substantial reduction in sedative and vasopressor doses without significant increases in intracranial pressure. 6

Anti-Inflammatory Benefits

• Ketamine exerts anti-inflammatory properties by inhibiting the release of proinflammatory cytokines including tumor necrosis factor-alpha and interleukin-6. 2
• Ketamine blocks nuclear factor-kappa B transcription, reduces systemic interleukin-6 production, and preserves an intact adrenal axis. 1
• Early ketamine administration reduces mortality in experimental sepsis models. 2

Critical Caveats and Limitations

Catecholamine Depletion

• In patients with severely depleted catecholamine reserves (end-stage septic shock), ketamine can paradoxically suppress myocardial contractility. 1
• For these high-risk patients, minimize sedative doses overall and have a lower threshold to initiate neuromuscular blockade rather than relying solely on ketamine. 1

FDA Warnings to Consider

• The FDA labels ketamine as contraindicated in patients for whom a significant elevation of blood pressure would constitute a serious hazard, though this is rarely relevant in hypotensive septic shock. 5
• Monitor vital signs and cardiac function during administration, as decreases in blood pressure, heart rate, arrhythmias, and cardiac decompensation have been observed despite ketamine's typical sympathomimetic effects. 5

Emergence Reactions

• Emergence delirium occurs in approximately 12% of patients, manifesting as dream-like states, vivid imagery, hallucinations, and confusion. 5
• Minimize emergence reactions by co-administering benzodiazepines and reducing verbal, tactile, and visual stimulation during recovery. 5

What to Avoid in Septic Shock

• The American College of Critical Care Medicine specifically recommends avoiding etomidate entirely for intubation in septic shock due to its independent association with increased mortality in both children and adults. 1
• While the Surviving Sepsis Campaign guidelines recommend norepinephrine as the first-choice vasopressor for septic shock, they do not address sedative choice—ketamine complements vasopressor therapy by reducing vasopressor requirements. 7, 6

Practical Algorithm for Septic Shock Intubation

1. Prepare ketamine 1-2 mg/kg IV + atropine + midazolam 0.05 mg/kg 1, 3
2. Consider adding lidocaine 1 mg/kg if concerned about hypotension (reduces ketamine dose to 0.5 mg/kg) 4
3. Avoid etomidate, propofol, and high-dose benzodiazepines 1
4. For ongoing sedation, initiate ketamine infusion at 0.3 mg/kg/hr 6
5. If patient has end-stage shock with suspected catecholamine depletion, minimize all sedatives and consider early neuromuscular blockade 1