Changes in dynamic arterial elastance induced by volume expansion and vasopressor in the operating room: a prospective bicentre study.

BACKGROUND: Dynamic arterial elastance (Eadyn), defined as the ratio between pulse pressure variations and stroke volume variations, has been proposed to assess functional arterial load. We evaluated the evolution of Eadyn during volume expansion and the effects of neosynephrine infusion in hypotensive and preload-responsive patients. METHODS: In this prospective bicentre study, we included 56 mechanically ventilated patients in the operating room. Each patient had volume expansion and neosynephrine infusion. Stroke volume and stroke volume variations were obtained using esophageal Doppler, and pulse pressure variations were measured through the arterial line. Pressure response to volume expansion was defined as an increase in mean arterial pressure (MAP) ≥ 10%. RESULTS: Twenty-one patients were pressure responders to volume expansion. Volume expansion induced a decrease in Eadyn (from 0.69 [0.58-0.85] to 0.59 [0.42-0.77]) related to a decrease in pulse pressure variations more pronounced than the decrease in stroke volume variations. Baseline and changes in Eadyn after volume expansion were related to age, history of arterial hypertension, net arterial compliance and effective arterial elastance. Eadyn value before volume expansion > 0.65 predicted a MAP increase ≥ 10% with a sensitivity of 76% (95% CI 53-92%) and a specificity of 60% (95% CI 42-76%). Neosynephrine infusion induced a decrease in Eadyn (from 0.67 [0.48-0.80] to 0.54 [0.37-0.68]) related to a decrease in pulse pressure variations more pronounced than the decrease in stroke volume variations. Baseline and changes in Eadyn after neosynephrine infusion were only related to heart rate. CONCLUSION: Eadyn is a potential sensitive marker of arterial tone changes following vasopressor infusion.

Personalization of arterial pressure in the perioperative period.

PURPOSE OF REVIEW: This review aims to discuss recent findings on the relationship between intraoperative arterial hypotension and organ dysfunction in surgical patients and examines the available evidence for personalizing blood pressure (BP) management as a strategy to improve patient outcome. RECENT FINDINGS: Hypotension contributes to oxygen supply-demand mismatch and may cause an ischemia-reperfusion injury which may manifest as organ dysfunction. Evidence is accumulating suggesting that hypotension is associated with acute postoperative myocardial and kidney injury, and increased risk of mortality in surgical patients. In contrast to traditional BP management in which BP targets are empirically chosen, personalized BP management aims at individualizing BP targets according to individual patient physiology considering clinical conditions that may influence organ pressure-flow autoregulation. Recent randomized data provide clinically meaningful findings that a treatment strategy aims at targeting individualized BP values which may help improving outcome in surgical patients. SUMMARY: Hypotension is a common complication in surgical patients and is an important trigger of organ injury in surgical patients. Personalized BP management may contribute at reducing postoperative organ dysfunction in surgical patients.