Changes in stroke volume induced by lung recruitment maneuver can predict fluid responsiveness during intraoperative lung-protective ventilation in prone position

Abstract

Background: The present study aimed to evaluate the reliability of hemodynamic changes induced by lung recruitment maneuver (LRM) in predicting stroke volume (SV) increase after fluid loading (FL) in prone position.

Methods: Thirty patients undergoing spine surgery in prone position were enrolled. Lung-protective ventilation (tidal volume, 6-7 mL/kg; positive end-expiratory pressure, 5 cmH₂O) was provided to all patients. LRM (30 cmH₂O for 30 s) was performed. Hemodynamic variables including mean arterial pressure (MAP), heart rate, SV, SV variation (SVV), and pulse pressure variation (PPV) were simultaneously recorded before, during, and at 5 min after LRM and after FL (250 mL in 10 min). Receiver operating characteristic curves were generated to evaluate the predictability of SVV, PPV, and SV decrease by LRM (ΔSV_LRM) for SV responders (SV increase after FL > 10%). The gray zone approach was applied for ΔSV_LRM.

Results: Areas under the curve (AUCs) for ΔSV_LRM, SVV, and PPV to predict SV responders were 0.778 (95% confidence interval: 0.590-0.909), 0.563 (0.371-0.743), and 0.502 (0.315-0.689), respectively. The optimal threshold for ΔSV_LRM was 30% (sensitivity, 92.3%; specificity, 70.6%). With the gray zone approach, the inconclusive values ranged 25 to 75% for ΔSV_LRM (including 50% of enrolled patients).

Conclusion: In prone position, LRM-induced SV decrease predicted SV increase after FL with higher reliability than traditional dynamic indices. On the other hand, considering the relatively large gray zone in this study, future research is needed to further improve the clinical significance.

Trial registration: UMIN Clinical Trial Registry UMIN000027966 . Registered 28th June 2017.

Keywords: Fluid responsiveness; Lung recruitment maneuver; Prone position; Stroke volume.

Fig. 1

Study protocol. LRM consisted of applying a continuous positive airway pressure of 30 cm H₂O for 30 s. Volume expansion consisted of an infusion of 250 mL HES given in 10 min. Five sets of hemodynamic measurements including mean arterial pressure, heart rate, stroke volume, stroke volume variation, and pulse pressure variation were performed. T0: baseline measurement in supine position; T1: baseline measurement in prone position 10 min after turning prone and before LRM; T2: at the end of LRM; T3: second baseline measurement 5 min after LRM; T4: after volume expansion. Abbreviations: LRM, lung recruitment maneuver; HES, hydroxyethyl starch

Fig. 2

Change in among responders and nonresponders to fluid loading at points T1 (before lung recruitment maneuver), T2 (at the end of lung recruitment maneuver), T3 (at 5 min after lung recruitment maneuver), and T4 (after volume expansion). SV, stroke volume

Fig. 3

Correlations between percentage change in SV after FL and percentage decrease in SV by LRM. SV, stroke volume; FL, fluid loading; LRM, lung recruitment maneuver

Fig. 4

Four quadrant plot analysis to examine the concordance between percentage change in SV after FL and percentage decrease in SV by LRM. SV, stroke volume; FL, fluid loading; LRM, lung recruitment maneuver

Fig. 5

Receiver operating characteristic curves for SVV_prone, PPV_prone, and ΔSV_LRM to distinguish responders (SV increase after fluid loading > 10%). SV, stroke volume; BP, blood pressure; SVV_prone, stroke volume variation at time point T3; PPV_prone, pulse pressure variation at time point T3; ΔSV_LRM, decrease in stroke volume by lung recruitment maneuver

Fig. 6

Gray zone for ΔSV_LRM. Blue and red lines denote sensitivity and specificity, respectively. The gray zone indicates the inconclusive range for each variable. ΔSV_LRM, decrease in stroke volume by lung recruitment maneuver; SV, stroke volume; LRM, lung recruitment maneuver