The impact of fluid optimisation before induction of anaesthesia on hypotension after induction

Abstract

Summary Intra‐operative hypotension is a known predictor of adverse events and poor outcomes following major surgery. Hypotension often occurs on induction of anaesthesia, typically attributed to hypovolaemia and the haemodynamic effects of anaesthetic agents. We assessed the efficacy of fluid optimisation for reducing the incidence of hypotension on induction of anaesthesia. This prospective trial enrolled 283 patients undergoing radical cystectomy and randomly allocated them to goal‐directed fluid therapy (n = 142) or standard fluid therapy (n = 141). Goal‐directed fluid therapy patients received fluid optimisation based on stroke volume response to passive leg raise before induction; those with positive passive leg raise received intravenous crystalloid fluid boluses until stroke volume was optimised. Baseline mean arterial pressure was measured on the morning of surgery and on arriving in the operating theatre. This post‐hoc analysis defined haemodynamic instability as either a > 30% relative drop in mean arterial pressure compared with baseline or absolute mean arterial pressure < 55 mmHg, within 15 min of induction. Forty‐two (30%) goal‐directed fluid therapy patients underwent fluid optimisation after finding an intravascular fluid deficit via passive leg raise testing; 106 (75%) goal‐directed fluid therapy and 112 (79%) standard fluid therapy patients met criteria for haemodynamic instability. There was no significant difference in the incidence of haemodynamic instability between the goal‐directed fluid therapy and standard fluid therapy groups using absolute mean arterial pressure drop below 55 mmHg (p = 0.58) or using pre‐surgical testing or pre‐surgical mean arterial pressure values as baseline (p = 0.21, p = 0.89, respectively); however, the difference in the incidence of haemodynamic instability was significant using the operating theatre baseline mean arterial pressure (p = 0.004). We conclude that fluid optimisation before induction of general anaesthesia did not significantly impact haemodynamic instability.

The impact of fluid optimisation before induction of anaesthesia on hypotension after induction

“…Based on our own data and the study by Kahn et al. , we clearly support the pre‐emptive administration of a vasopressor early in the induction phase and throughout surgery in this patient population.…”

“…We read the article by Khan et al. with great interest and congratulate the authors, as we consider the tested hypothesis to be enormously relevant for clinical practice. The primary finding was that pre‐emptive stroke volume optimisation by fluid loading before anaesthesia induction is ineffective in preventing significant hypotension, a condition known to be associated with increased mortality after major surgery.…”

The impact of fluid optimisation before induction of anaesthesia on hypotension after induction: a reply

“…We thank Engel et al [1] for their response to our recent article [2] and agree with their opinion regarding the use of vasopressors for the prevention and treatment of peri‐operative hypotensive episodes. We also commend their previous work [3].…”

Post‐induction hypotension: a fluid relationship?

“…Pre-operative hypovolaemia is traditionally acknowledged as a risk factor for post-induction hypotension but does the corollary hold true, that is, will euvolaemia prevent post-induction hypotension? Kahn et al attempt to answer this question in a recent issue of Anaesthesia [3]. At the outset, it is worth bearing in mind that this is a secondary analysis of data obtained from patients recruited for a trial There are a number of strengths to the study.…”

“…Kahn et al. attempt to answer this question in a recent issue of Anaesthesia 3. At the outset, it is worth bearing in mind that this is a secondary analysis of data obtained from patients recruited for a trial evaluating goal‐directed fluid therapy vs. standard fluid therapy in the recovery of bowel function after radical cystectomy.…”