All intraoperative hypotension is not created equal - A call for an individualized approach

Intraoperative arterial pressure management: knowns and unknowns

Preventing postoperative organ dysfunction is integral to the practice of anaesthesia. Although intraoperative hypotension is associated with postoperative end organ dysfunction, there remains ambiguity with regards to its definition, targets, thresholds for initiating treatment, and ideal treatment modalities.

Blood Pressure Goals in Critically Ill Patients

Blood pressure goals in the intensive care unit (ICU) have been extensively investigated in large datasets and have been associated with various harm thresholds at or greater than a mean pressure of 65 mm Hg. While it is difficult to perform interventional randomized trials of blood pressure in the ICU, important evidence does not support defense of a higher pressure, except in retrospective database analyses. Perfusion pressure may be a more important target than mean pressure, even more so in the vulnerable patient population. In the cardiac ICU, blood pressure targets are tailored to specific cardiac pathophysiology and patient characteristics. Generally, the goal is to maintain adequate blood pressure within a certain range to support cardiac function and to ensure end organ perfusion. Individualized targets demand the use of both invasive and noninvasive monitoring modalities and frequent titration of medications and/or mechanical circulatory support where necessary. In this review, we aim to identify appropriate blood pressure targets in the ICU, recognizing special patient populations and outlining the risk factors and predictors of end organ failure.

Breaking Down the Evidence: Does Perioperative Hypotension Cause Kidney Injury?

BACKGROUND

Acute kidney injury (AKI) is common in the postoperative period and is associated with negative patient outcomes. The definition of perioperative hypotension is wide, but it is associated with various complications, including AKI.

SUMMARY

Preclinical data suggest that sustained severe renal hypoperfusion per se does not cause persistent AKI. The evidence associating blood pressure levels and postoperative renal dysfunction is predominantly retrospective and observational, and therefore potentially misled by the complex interactions between exposures, confounders, and mediators.

KEY MESSAGES

To better understand how perioperative hemodynamic management could affect the occurrence of kidney injury, it is pivotal to further investigate the association between hypotension and kidney dysfunction in the perioperative period and determine the degree to which hypotension is a causal factor.