Changes in peripheral perfusion index during intraoperative end-expiratory occlusion tests do not predict the response to fluid administration in patients undergoing lung protective ventilation.

Abstract

The end-expiratory occlusion test (EEOT) may predict the response to fluid administration in patients undergoing lung-protective ventilation, but arterial catheter insertion is necessary to evaluate changes in stroke volume (SV). The peripheral perfusion index is a potential noninvasive alternative to evaluate SV. The aim of this study is to investigate whether changes in perfusion index during an intraoperative EEOT can predict the response to fluid administration in patients undergoing lung-protective ventilation (tidal volume 7ml/kg predicted body weight). Forty-one elective surgical patients were enrolled. The SV and perfusion index were recorded before (baseline), during a 40-s EEOT and after volume expansion (250ml of lactated Ringer's solution over 10min). Patients with an increase in SV greater than 10% after volume expansion were defined as responders. ΔPI (change in perfusion index between baseline and 20 (ΔPI20) or 40s (ΔPI40) after the beginning of EEOT were calculated using: ΔPI20 (%) = [(PI at 20s after EEOT beginning-PIbaseline)/PIbaseline] × 100, ΔPI40 (%) = [(PI at 40s after EEO beginning-PIbaseline)/PIbaseline] × 100). Sixteen patients were responders, and 25 were non-responders. The area under the receiver operating characteristics curves generated for ΔPI20 and ΔPI40 to predict response to a fluid challenge were 0.561 (95% CI 0.374-0.749) and 0.688 (95% CI 0.523-0.852), respectively. Changes in perfusion index during intraoperative EEOT in patients undergoing lung-protective ventilation (7ml/kg) were unable to predict the response to fluid administration.