Hemodynamic monitoring by USCOM during rapid sequence intubation (RSI) with Etomidate/Fentanyl or Ketamine/Midazolam

Abstract

Background: Critically ill and septic patients often require emergency orotracheal intubation. Etomidate is associated with a reversible adrenal insufficiency which potentially increases the in-hospital mortality, particularly in patients with sepsis. Moreover; standard anesthetization might severely aggravate shock symptoms during rapid sequence induction (RSI). Ketamine with its known stabilizing effects on hemodynamics might be a reasonable alternative, particularly in septic patients. Methods: This non-randomised, observational pilot study focuses on the influence of ketamine-based (K) vs an etomidate-based (E) anesthetization on hemodynamic parameters during RSI. Forty pts were assigned alternately to etomidate/fentanyl (n=20), or ketamine/midazolam (n=20) while monitoring with invasive blood pressure (IBP) and ultrasound cardiac output monitor (USCOM) measurements during RSI. The levels of vasopressors required prior to, during and after RSI were recorded. Results: Fourty patients (median SAPS II score at ICU admission: 54 K, 50 E; median age: 59 yrs K, 56 yrs E) who needed sedation for emergency intubation were sedated either with etomidate/fentanyl or ketamine/midazolam. Noradrenalin demand and mean arterial pressure (MAP) prior to RSI were comparable (E: mean NA dose 0.2 mg/h, MAP 88 mmHg; K: mean NA dose 0.45 mg/h, MAP 75 mmHg) between the two groups. Moreover, mean MAP levels post RSI were 75 (E) and 76 (K) mmHg, respectively. The mean peak level of noradrenalin demand during RSI, though, was considerably higher within the etomidate group compared to the ketamine group (E 7.6 mg/h vs K 1.06 mg/h, p 0.01). Stroke volume index (SVI) and cardiac index (CI) increased during RSI (+3.8%/+3.0%) within the ketamine group, while SVI and CI decreased during RSI (-8.5%/-3.5%) within the etomidate group. Conclusion: USCOM is an easily applicable and quick tool for the hemodynamic monitoring of critical ill patients. Moreover, this pilot study shows that RSI with ketamine/midazolam is a safe and valuable alternative to etomidate/ fentanyl in patients who primarily require vasopressors.