Etomidate: to use or not to use for endotracheal intubation in the critically ill?

Risk factors for and prediction of post-intubation hypotension in critically ill adults: A multicenter prospective cohort study

Objective

Hypotension following endotracheal intubation in the ICU is associated with poor outcomes. There is no formal prediction tool to help estimate the onset of this hemodynamic compromise. Our objective was to derive and validate a prediction model for immediate hypotension following endotracheal intubation.

Methods

A multicenter, prospective, cohort study enrolling 934 adults who underwent endotracheal intubation across 16 medical/surgical ICUs in the United States from July 2015-January 2017 was conducted to derive and validate a prediction model for immediate hypotension following endotracheal intubation. We defined hypotension as: 1) mean arterial pressure <65 mmHg; 2) systolic blood pressure <80 mmHg and/or decrease in systolic blood pressure of 40% from baseline; 3) or the initiation or increase in any vasopressor in the 30 minutes following endotracheal intubation.

Results

Post-intubation hypotension developed in 344 (36.8%) patients. In the full cohort, 11 variables were independently associated with hypotension: increasing illness severity; increasing age; sepsis diagnosis; endotracheal intubation in the setting of cardiac arrest, mean arterial pressure <65 mmHg, and acute respiratory failure; diuretic use 24 hours preceding endotracheal intubation; decreasing systolic blood pressure from 130 mmHg; catecholamine and phenylephrine use immediately prior to endotracheal intubation; and use of etomidate during endotracheal intubation. A model excluding unstable patients’ pre-intubation (those receiving catecholamine vasopressors and/or who were intubated in the setting of cardiac arrest) was also developed and included the above variables with the exception of sepsis and etomidate. In the full cohort, the 11 variable model had a C-statistic of 0.75 (95% CI 0.72, 0.78). In the stable cohort, the 7 variable model C-statistic was 0.71 (95% CI 0.67, 0.75). In both cohorts, a clinical risk score was developed stratifying patients’ risk of hypotension.

Conclusions

A novel multivariable risk score predicted post-intubation hypotension with accuracy in both unstable and stable critically ill patients.

Study registration

Clinicaltrials.gov identifier: NCT02508948 and Registered Report Identifier: RR2-10.2196/11101.

ET-26 hydrochloride (ET-26 HCl) has similar hemodynamic stability to that of etomidate in normal and uncontrolled hemorrhagic shock (UHS) rats

Objective

ET-26 HCl is a promising sedative–hypnotic anesthetic with virtually no effect on adrenocortical steroid synthesis. However, whether or not ET-26 HCl also has a sufficiently wide safety margin and hemodynamic stability similar to that of etomidate and related compounds remains unknown. In this study, the effects of ET-26 HCl, etomidate and propofol on therapeutic index, heart rate (HR), mean arterial pressure (MAP), maximal rate for left ventricular pressure rise (D_max/t), and maximal rate for left ventricular pressure decline (D_min/t) were investigated in healthy rats and a rat model of uncontrolled hemorrhagic shock (UHS).

Methods

50% effective dose (ED₅₀) and 50% lethal dose (LD₅₀) were determined after single bolus doses of propofol, etomidate, or ET-26 HCl using the Bliss method and the up and down method, respectively. All rats were divided into either the normal group and received either etomidate, ET-26 HCl or propofol, (n = 6 per group) or the UHS group and received either etomidate, ET-26 HCl or propofol, (n = 6 per group). In the normal group, after preparation for hemodynamic and heart-function monitoring, rats were administered a dose of one of the test agents twofold-higher than the established ED₅₀, followed by hemodynamic and heart-function monitoring. Rats in the UHS group underwent experimentally induced UHS with a target arterial pressure of 40 mmHg for 1 hour, followed by administration of an ED₅₀ dose of one of the experimental agents. Blood-gas analysis was conducted on samples obtained during equilibration with the experimental setup and at the end of the experiment.

Results

In the normal group, no significant differences in HR, MAP, D_max/t and D_min/t (all P > 0.05) were observed at any time point between the etomidate and ET-26 HCl groups, whereas HR, MAP and D_max/t decreased briefly and D_min/t increased following propofol administration. In the UHS group, no significant differences in HR, MAP, D_max/t and D_min/t were observed before and after administration of etomidate or ET-26 HCl at ED₅₀ doses (all P > 0.05). Administration of propofol resulted in brief, statistically significant reductions in HR and D_max/t, with a brief increase in D_min/t (P ˂ 0.05), while no significant differences in MAP were observed among the three groups. The blood-lactate concentrations of rats in the ET-26 HCl group were significantly lower than those in etomidate and propofol groups (P ˂ 0.05).

Conclusions

ET-26 HCl provides a similar level of hemodynamic stability to that obtained with etomidate in both healthy rats, and rat models of UHS. ET-26 HCl has the potential to be a novel induction anesthetic for use in critically ill patients.