Stroke volume optimization after anaesthetic induction: An open randomized controlled trial comparing 0.9% NaCl...

Area of Science:

• Anesthesiology
• Cardiovascular Physiology
• Fluid Resuscitation

Background:

• Postinduction hypotension is a common complication during general anesthesia.
• Fluid infusion is used for cardiac preload optimization to manage hypotension.
• The choice between colloid (HES) and crystalloid (0.9% NaCl) for fluid resuscitation remains debated.

Purpose of the Study:

• To compare the efficacy of hydroxyethyl starch (HES) versus 0.9% sodium chloride (NaCl) in optimizing stroke volume (SV) after anesthesia induction.
• To determine the number of fluid challenges required for SV optimization with each fluid type.
• To assess the need for ephedrine to restore arterial pressure in patients receiving either HES or 0.9% NaCl.

Main Methods:

• An open, randomized, prospective parallel-group study involving 56 adult patients undergoing orthopedic surgery.
• Patients were randomly assigned to receive either 0.9% NaCl or HES.
• Cardiac preload optimization was guided by esophageal Doppler, using 250ml fluid challenges until SV increased by less than 10%.

Main Results:

• No significant difference was observed in the number of fluid challenges required for SV optimization between the 0.9% NaCl group (2 challenges) and the HES group (2 challenges).
• The percentage of patients responding to the first fluid challenge was similar in both groups (61% for 0.9% NaCl vs. 63% for HES).
• There was no significant difference in the proportion of patients requiring ephedrine or the dose of ephedrine administered between the two groups.

Conclusions:

• Both crystalloid (0.9% NaCl) and colloid (HES) are equally effective in expanding intravascular volume immediately after administration.
• These fluids similarly correct postinduction hypotension following general anesthesia.
• The choice of fluid does not impact the immediate efficacy in preload optimization and hypotension management.