PREPARE II RCT – Does a Bolus Reduce Cardiovascular Collapse Post-Intubation?

July 15, 2022

Written by Gabby Leonard

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A 500mL fluid bolus does not reduce the incidence of cardiovascular collapse in critically ill patients undergoing endotracheal intubation.

Why does this matter?
25-40% of critically ill patients undergoing intubation develop hypotension, which can cause cardiac arrest and ultimately death. This occurs due to vasodilation, increased intrathoracic pressure and decreased preload. About that preload…does administering a 500mL fluid bolus immediately prior to anesthesia induction reduce risk of cardiovascular collapse?

How low can you go? Can you go down low?
This was a multicenter RCT with 1,067 critically ill patients undergoing intubation who were randomized to a bolus or no bolus prior to induction. Cardiovascular collapse was defined as new or increased vasopressor requirement or systolic blood pressure <65mm Hg during the time period from induction of anesthesia until 2 minutes post intubation. Primary outcomes also included cardiac arrest or death up to 1 hour after intubation. Interestingly, 21% of patients who received a 500cc bolus developed cardiovascular collapse compared to 18.2% who did not receive a fluid bolus (2.8% absolute difference, [95%CI -2.2% to 7.7%], p =0.25). Additionally, more patients in the fluid bolus group required new or increased vasopressors compared to those who did not receive a fluid bolus (20.6% vs 17.6%). Patients who received a fluid bolus experienced a higher frequency of cardiac arrest (1.7% vs. 1.5%) as well as death (0.7% vs 0.6%).

There is the possibility of bias due to lack of blinding and the fact that 15% of patients were excluded due to the urgency of intubation. Regardless, it looks like a fluid bolus probably isn’t the answer.

Editor’s note: In unstable patients, we really need more research on using vasopressors proactively in the peri-intubation period. Here’s a study idea for you! ~Clay Smith

Source
Effect of Fluid Bolus Administration on Cardiovascular Collapse Among Critically Ill Patients Undergoing Tracheal Intubation: A Randomized Clinical Trial. JAMA. 2022 Jun 16. doi: 10.1001/jama.2022.9792. Online ahead of print.