Effect of Preoperative Intravenous Crystalloid Bolus on Postinduction Blood Pressure: A Randomized Blinded Intervention Trial.

BACKGROUND

Postinduction hypotension in major noncardiac surgery is common and a modifiable risk factor for adverse outcomes. There is an ongoing debate whether preoperative crystalloid fluid administration can reduce the incidence or severity of postinduction hypotension. This study aims to assess whether a preoperative intravenous crystalloid bolus reduces postinduction hypotension in high-risk patients during general anesthesia.

METHODS

This was a prospective, randomized, single-blind clinical trial conducted at two centers in Austria (Medical University of Graz, Medical University of Vienna). Adult patients 45 yr and older with cardiovascular risk factors undergoing major surgery were enrolled and randomly assigned to receive a preoperative crystalloid bolus within 60 ± 15 min before anesthetic induction, or to receive standard care. The primary outcome was the time-weighted average mean arterial pressure of less than 65 mmHg within the first 20 min after induction or until surgical incision.

RESULTS

Of the 504 patients analyzed (247 in the intervention group and 257 in the control group), no statistically significant difference in median time-weighted average of the mean arterial pressure less than 65 mmHg was observed (intervention group, 0.0 mmHg; interquartile range, 0.0 to 0.56; standard of care group, 0.0 mmHg; interquartile range, 0.0 to 0.84; P = 0.368).

CONCLUSIONS

In this blinded randomized clinical trial, administering a crystalloid fluid bolus within 60 min before surgery did not significantly reduce the time-weighted average of a mean arterial pressure less than 65 mmHg compared to standard care in patients with cardiovascular risk factors undergoing major noncardiac surgery. This study suggests that administering crystalloids before surgery does not prevent postinduction hypotension.