Effect of Fluid Bolus Administration on Cardiovascular Collapse Among Critically Ill Patients Undergoing Tracheal Intubation: A Randomized Clinical Trial

Abstract

Importance: Hypotension is common during tracheal intubation of critically ill adults and increases the risk of cardiac arrest and death. Whether administering an intravenous fluid bolus to critically ill adults undergoing tracheal intubation prevents severe hypotension, cardiac arrest, or death remains uncertain.

Objective: To determine the effect of fluid bolus administration on the incidence of severe hypotension, cardiac arrest, and death.

Design, setting, and participants: This randomized clinical trial enrolled 1067 critically ill adults undergoing tracheal intubation with sedation and positive pressure ventilation at 11 intensive care units in the US between February 1, 2019, and May 24, 2021. The date of final follow-up was June 21, 2021.

Interventions: Patients were randomly assigned to receive either a 500-mL intravenous fluid bolus (n = 538) or no fluid bolus (n = 527).

Main outcomes and measures: The primary outcome was cardiovascular collapse (defined as new or increased receipt of vasopressors or a systolic blood pressure <65 mm Hg between induction of anesthesia and 2 minutes after tracheal intubation, or cardiac arrest or death between induction of anesthesia and 1 hour after tracheal intubation). The secondary outcome was the incidence of death prior to day 28, which was censored at hospital discharge.

Results: Among 1067 patients randomized, 1065 (99.8%) completed the trial and were included in the primary analysis (median age, 62 years [IQR, 51-70 years]; 42.1% were women). Cardiovascular collapse occurred in 113 patients (21.0%) in the fluid bolus group and in 96 patients (18.2%) in the no fluid bolus group (absolute difference, 2.8% [95% CI, -2.2% to 7.7%]; P = .25). New or increased receipt of vasopressors occurred in 20.6% of patients in the fluid bolus group compared with 17.6% of patients in the no fluid bolus group, a systolic blood pressure of less than 65 mm Hg occurred in 3.9% vs 4.2%, respectively, cardiac arrest occurred in 1.7% vs 1.5%, and death occurred in 0.7% vs 0.6%. Death prior to day 28 (censored at hospital discharge) occurred in 218 patients (40.5%) in the fluid bolus group compared with 223 patients (42.3%) in the no fluid bolus group (absolute difference, -1.8% [95% CI, -7.9% to 4.3%]; P = .55).

Conclusions and relevance: Among critically ill adults undergoing tracheal intubation, administration of an intravenous fluid bolus compared with no fluid bolus did not significantly decrease the incidence of cardiovascular collapse.

Trial registration: ClinicalTrials.gov Identifier: NCT03787732.

Figure 1.. Flow of Participants Through the PREPARE II Trial

PREPARE II indicates Preventing Cardiovascular Collapse With Administration of Fluid Resuscitation During Induction and Intubation.

Figure 2.. Effect of Fluid Bolus Administration on Cardiovascular Collapse

^aScores on the Acute Physiology and Chronic Health Evaluation (APACHE) II can range from 0 to 71; higher scores indicate a greater severity of illness. Patients were dichotomized at the median APACHE II score of the cohort, which was 19. ^bRefers to patients who received vasopressors or inotropes within the hour prior to enrollment. ^cPredicted probability of cardiovascular collapse was calculated from age, systolic blood pressure at induction of anesthesia, APACHE II score, use of vasopressors, presence of cirrhosis, oxygen saturation at induction of anesthesia, presence or absence of a procedural indication for tracheal intubation, the anesthetic agent used, the neuromuscular blocking agent used, indication for tracheal intubation, presence of chronic kidney disease, and sex (additional details appear in eFigure 6 in Supplement 2).