Key result
A fluid-induced increase in radial artery pulse pressure of >16% detected fluid responsiveness with an AUROC of 0.881 (95% CI 0.802-0.937), whereas passive leg raising was an unreliable predictor.
Why the study?
Cardiac output or stroke volume monitoring to assess fluid responsiveness is often unavailable in clinical practice, prompting evaluation of whether radial artery pulse pressure changes track stroke volume changes.
Can changes in radial artery pulse pressure detect changes in stroke volume after fluid challenge or passive leg raising in mechanically ventilated patients after cardiac surgery?
Observational (n=102)
Can changes in radial artery pulse pressure detect changes in stroke volume after fluid challenge or passive leg raising in mechanically ventilated patients after cardiac surgery?
Effect estimate: AUROC 0.881 (95% CI 0.802-0.937)
Changes in radial artery pulse pressure can reliably detect stroke volume changes after fluid challenge, but not after passive leg raising, in mechanically ventilated patients post-cardiac surgery.
ΔrPP after fluid challenge tracks SV changes post-cardiac surgery; leaves open whether it reliably guides volume decisions in routine practice.
BACKGROUND: Fluid responsiveness is defined as an increase in cardiac output (CO) or stroke volume (SV) of >10-15% after fluid challenge (FC). However, CO or SV monitoring is often not available in clinical practice. The aim of this study was to evaluate whether changes in radial artery pulse pressure (rPP) induced by FC or passive leg raising (PLR) correlates with changes in SV in patients after cardiac surgery. METHODS: This prospective observational study included 102 patients undergoing cardiac surgery, in which rPP and SV were recorded before and immediately after a PLR test and FC with 250 mL of Gelofusine for 10 min. SV was measured using pulse contour analysis. Patients were divided into responders (≥15% increase in SV after FC) and non-responders. The hemodynamic variables between responders and non-responders were analyzed to assess the ability of rPP to track SV changes. RESULTS: A total of 52% patients were fluid responders in this study. An rPP increase induced by FC was significantly correlated with SV changes after a FC (ΔSV-FC, r=0.62, P<0.01). A fluid-induced increase in rPP (ΔrPP-FC) of >16% detected a fluid-induced increase in SV of >15%, with a sensitivity of 91% and a specificity of 73%. The area under the receiver operating characteristic curve (AUROC) for the fluid-induced changes in rPP identified fluid responsiveness was 0.881 (95% CI: 0.802-0.937). A grey zone of 16-34% included 30% of patients for ΔrPP-FC. The ΔrPP-PLR was weakly correlated with ΔSV-FC (r=0.30, P<0.01). An increase in rPP induced by PLR (ΔrPP-PLR) predicted fluid responsiveness with an AUROC of 0.734 (95% CI: 0.637-0.816). A grey zone of 10-23% included 52% of patients for ΔrPP-PLR. CONCLUSIONS: Changes in rPP might be used to detect changes in SV via FC in mechanically ventilated patients after cardiac surgery. In contrast, changes in rPP induced by PLR are unreliable predictors of fluid responsiveness.
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Hou et al. (2020) conducted an observational in cardiac surgery (n=102). Changes in radial artery pulse pressure (rPP) was evaluated on fluid responsiveness (≥15% increase in stroke volume after fluid challenge) (AUROC 0.881, 95% CI 0.802-0.937). A fluid-induced increase in radial artery pulse pressure of >16% detected fluid responsiveness with an AUROC of 0.881 (95% CI 0.802-0.937), whereas passive leg raising was an unreliable predictor.
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