Hemodynamics, fluids & transfusion
Changes in central venous-to-arterial PCO2 difference and central venous oxygen saturation as markers to define fluid responsiveness in critically ill patients: a pot-hoc analysis of a multi-center prospective study
Authors' conclusion
In mechanically critically ill patients, ΔP(v-a)CO2 and ΔScvO2 are reliable parameters to define FR and can be used in the absence of CI measurement. The response to VE was independent of baseline ScvO2 and P(v-a)CO2 levels.
Study context
- Population
- Sedated, mechanically ventilated septic patients with acute circulatory failure115 fluid responders
- Participants
- 205 participants
- Comparison
- ΔPCO2 vs ΔScvO2 after volume expansion (VE) to define fluid responsiveness (FR)
- Primary endpoint
- Accuracy (AUC) of ΔP(v-a)CO2 and ΔScvO2 to define FR (VE-induced increase in CI > 15%)
Methodological detailsdiagnostic accuracy
- Diagnostic accuracy
Primary result
As reported in the abstract
AUC to define FR
| Group | Value | p | Cut-off | PPV | NPV | Gray zone | Patients in gray zone |
|---|---|---|---|---|---|---|---|
| ΔP(v-a)CO2 | AUC 0.831 (95% CI 0.772–0.880) | p < 0.001 | ≤ 2.1 mmHg | 90% | 58% | - 2 to 0 mmHg | 22% |
| ΔScvO2 | AUC 0.801 (95% CI 0.739–0.853) | p < 0.001 | ≥ 3.4% | 86% | 64% | - 1 to 5% | 40.5% |
Value
ΔP(v-a)CO2AUC 0.831 (95% CI 0.772–0.880)
ΔScvO2AUC 0.801 (95% CI 0.739–0.853)
p
ΔP(v-a)CO2p < 0.001
ΔScvO2p < 0.001
Cut-off
ΔP(v-a)CO2≤ 2.1 mmHg
ΔScvO2≥ 3.4%
PPV
ΔP(v-a)CO290%
ΔScvO286%
NPV
ΔP(v-a)CO258%
ΔScvO264%
Gray zone
ΔP(v-a)CO2- 2 to 0 mmHg
ΔScvO2- 1 to 5%
Patients in gray zone
ΔP(v-a)CO222%
ΔScvO240.5%
Further findings
Fluid responders
- Patients classified as fluid responders
- 115 (56.1%)
Multivariable analysis
- ΔP(v-a)CO2 and ΔScvO2 independently associated with FR
Baseline ScvO2 and P(v-a)CO2 and FR
- No significant relationships between pre-infusion ScvO2 and P(v-a)CO2 levels and FR
Original publication
Changes in central venous-to-arterial PCO2 difference and central venous oxygen saturation as markers to define fluid responsiveness in critically ill patients: a pot-hoc analysis of a multi-center prospective study. Crit Care. Published 8 November 2024. doi:10.
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