Effect of Pre-operative Intravenous Crystalloid Bolus on Post-Induction Blood Pressure - a randomized blinded intervention trial.

Summary

In this two-center randomized blinded trial of 504 high-risk adults undergoing major non-cardiac surgery, a crystalloid bolus administered within approximately 60 minutes before induction did not reduce the time-weighted average of mean arterial pressure below 65 mmHg during the first 20 minutes after induction. The negative result challenges routine preoperative fluid loading as a strategy to prevent post-induction hypotension.

Key Findings

• The analysis included 504 patients: 247 received preoperative crystalloid and 257 received standard care.
• The time-weighted average of mean arterial pressure below 65 mmHg did not differ significantly between groups: 0.0 mmHg versus 0.0 mmHg, P=0.368.
• A crystalloid bolus within 60 minutes before induction did not prevent post-induction hypotension.

Clinical Implications

Routine pre-induction crystalloid boluses should not be assumed to prevent post-induction hypotension in cardiovascular-risk patients undergoing major non-cardiac surgery. Clinicians should prioritize individualized hemodynamic assessment, appropriate vasopressor readiness, and targeted treatment of hypotension.

Limitations

• The intervention was single-blind rather than fully double-blind.
• The findings apply primarily to patients aged 45 years or older with cardiovascular risk factors undergoing major non-cardiac surgery and may not generalize to other populations or fluid strategies.

Future Directions

Future trials should compare individualized fluid and vasopressor strategies, incorporate baseline volume-responsiveness assessment, and evaluate patient-centered outcomes such as organ injury, postoperative complications, and length of stay.