Association of the intraoperative peripheral perfusion index with postoperative morbidity and mortality in acute surgical patients: a retrospective observational multicentre cohort study

Abstract

Background: We hypothesised that in acute high-risk surgical patients, a lower intraoperative peripheral perfusion index (PPI) would indicate a higher risk of postoperative complications and mortality. Methods: This retrospective observational study included 1338 acute high-risk surgical patients from November 2017 until October 2018 at two University Hospitals in Denmark. Intraoperative PPI was the primary exposure variable and the primary outcome was severe postoperative complications defined as a ClavieneDindo Class !III or death, within 30 days. Results: intraoperative PPI was associated with severe postoperative complications or death: odds ratio (OR) 1.12 (95% confidence interval [CI] 1.05e1.19; P<0.001), with an association of intraoperative mean PPI 0.5 and PPI 1.5 with the primary outcome: OR 1.79 (95% CI 1.09e2.91; P¼0.02) and OR 1.65 (95% CI 1.20e2.27; P¼0.002), respectively. Each 15-min increase in intraoperative time spend with low PPI was associated with the primary outcome (per 15 min with PPI 0.5: OR 1.11 (95% CI 1.05e1.17; P<0.001) and with PPI 1.5: OR 1.06 (95% CI 1.02e1.09; P¼0.002)). Thirty-day mortality in patients with PPI 0.5 was 19% vs 10% for PPI >0.5, P¼0.003. If PPI was 1.5, 30-day mortality was 16% vs 8% in patients with a PPI >1.5 (P<0.001). In contrast, intraoperative mean MAP 65 mm Hg was not significantly associated with severe postoperative complications or death (OR 1.21 [95% CI 0.92e1.58; P¼0.2]). Conclusions: Low intraoperative PPI was associated with severe postoperative complications or death in acute high-risk surgical patients. To guide intraoperative haemodynamic management, the PPI should be further investigated.

Perfusion index: Physical principles, physiological meanings and clinical implications in anaesthesia and critical care

“…In a large recent and retrospective study, intraoperative PI was associated with severe postoperative complications or death (lower values being associated with worse outcomes) in a time-dependent manner even after adjustment for confounding variables [47]. Furthermore, they observed that the association between PI with the primary outcome was higher in patients with MAP > 65 mmHg compared to patients with MAP ≤ 65 mmHg (OR = 1.17; 95% CI 1.09-1.27; p < 0.001 vs. OR = 1.07; 95% CI 1.02-1.13; p = 0.011; respectively), suggesting a degree of incoherence between systemic haemodynamic and microcirculation.…”

What is new in hemodynamic monitoring and management?

“…It is assumed that systemic hemodynamics – reflected by cardiac output or blood pressure – are coupled with microcirculatory tissue perfusion. The peripheral perfusion index is a photoplethysmography-derived microcirculatory tissue perfusion variable that has been associated with impaired outcome in surgical patients [ 23 , 24 ].…”

“…These studies show the vast potential of measuring the peripheral perfusion index. A recent retrospective study further showed a strong correlation between impaired intraoperative peripheral perfusion index and postoperative outcomes [ 23 ]. With growing evidence showing the importance of the peripheral perfusion index, it will be interesting to see how photoplethysmography and the peripheral perfusion index can be integrated into hemodynamic monitoring and management.…”

Blood pressure and flow in pediatric anesthesia: An educational review

“…Peripheral perfusion index (PPI) is generated from the pulse oximetry signal, and changes in peripheral perfusion, both from reduced CO and sympathetically mediated peripheral vasoconstriction to augment central blood volume, are reflected in PPI 25 . In a recent study based on more than 1.000 acute high‐risk adult surgical patients, it was clearly shown that low PPI values during anesthesia are linked to a higher risk for severe postoperative complications and/or death 25 . Interestingly, no such correlation could be found with regard to low blood pressure (defined as MAP ≤65 mm Hg).…”