Real-time changes in pulse pressure during a 10-second end-expiratory occlusion test reliably detect preload responsiveness.

Background: The end-expiratory occlusion (EEO) test detects preload responsiveness through changes in cardiac index (ΔCI) during a 15-second respiratory hold at end-expiration. We investigated the diagnostic accuracy of EEO-induced changes in arterial pulse pressure (∆PP), especially when the duration of EEO is reduced to 10'' and 5'', and whether adding an end-inspiratory occlusion (EIO) improves this diagnostic accuracy.

Methods: In 143 mechanically ventilated patients with sinus rhythm, EEO and EIO were performed while recording ΔCI and ∆PP values. Either a fluid bolus-induced ΔCI ≥ 15% or a passive leg raising-induced ΔCI ≥ 10% defined preload responsiveness. The effects of the EEO and EIO tests on PP and CI were evaluated as the percentage difference between values averaged either over the last five seconds of the 15-sec respiratory holds (ΔPP and ΔPP, ΔCI and ΔCI), or between the 5th and the 10th seconds of the 15-sec respiratory holds (ΔPP and ΔPP, ΔCI and ΔCI), or during the five first seconds of respiratory holds (ΔPP and ΔPP, ΔCI and ΔCI) and baseline.

Results: Sixty-one (43%) patients were preload responders. Both ∆CI and ∆CI were higher in responders than in non-responders (5.8 [4.5-7.3]% vs. 1.1 [0.1-3.4]% and 3.0 [2.4-4.3]% vs. 0.6 [0.1-1.6]%, respectively; p < 0.001), whereas ∆CI did not differ between responders and non-responders. ∆PP, ∆PP and ∆PP were significantly higher in responders than in non-responders (5.2 [2.8-8.7]% vs. 1.2 [0.3-2.8]%, 7.7 [5.0-12.4]% vs. 1.8 [0.5-3.1]% and 8.1 [5.1-11.8]% vs. 1.5 [0.5-3.0]%, respectively; p < 0.001). For detecting preload responsiveness, compared to the area under the receiver operating characteristic (AUROC) of ∆CI (0.935 [0.881-0.969]), the AUROC of ∆CI was similar (0.910 [0.851-0.951], p = 0.410), but the AUROC of ∆CI was smaller (0.541 [0.456-0.625], p < 0.001); the AUROC of ∆PP (0.913 [0.857-0.952], p = 0.346), and ∆PP (0.912 [0.860-0.947], p = 0.336) were similar, but the AUROC of ∆PP (0.834 (0.763-0.891, p = 0.005) was significantly smaller. Evaluation of ∆CI and ∆PP did not enhance reliability of the test at each test duration.

Conclusion: In ventilated patients with sinus rhythm, real-time changes in PP during a 10-second EEO reliably detect preload responsiveness.

Trial Registration: No. IDRCB 2010A0095942. Registered 04 January 2010.