Key result
Prone position without volume expansion linked to ~45% higher PPV vs supine before BP changes.
Why the study?
Pulse pressure variation predicts fluid responsiveness in supine and prone positions, but changes in PPV induced by prone positioning during spinal surgery needed evaluation.
Does the prone position without volume expansion alter pulse pressure variation in patients undergoing spinal surgery?
Observational (n=96)
Does the prone position without volume expansion alter pulse pressure variation in patients undergoing spinal surgery?
Mean Difference: 4.7
Absolute Event Rate: 15.2% vs 10.5%
p-value: p=<0.001
Prone positioning without volume expansion significantly increases pulse pressure variation independently of changes in arterial blood pressure and heart rate.
May confound PPV-guided fluid assessment in prone spinal surgery; leaves open need for position-specific validation in prospective trials.
Background : Pulse pressure variation (PPV) is a predictor of fluid responsiveness in supine patients under mechanical ventilation. Its use has also been validated in the prone position. The aim of this study was to assess changes in PPV induced by prone position in patients undergoing spinal surgery. Methods : Ninety-six patients aged 12 to 75 years, scheduled for elective spinal surgery were included. Patients were excluded if they had clinical signs related to any organ failure, or if they required vasoactive drugs and/or volume expansion during the early stages of anesthesia. Patients received a standardized anesthesia protocol. Fluid expansion was not allowed from induction until 10 minutes after positioning. Hemodynamic measurements recorded before the induction of anesthesia (T0) included : arterial pressure (systolic (SAP) diastolic (DAP) and mean (MAP)) and heart rate (HR). Radial artery was cannulated after intubation and measurements, as well as PPV, were noted in supine position (T1). Patients were then placed in prone position hemodynamics and PPV measurements were repeated (T2). Results : Forty-eight patients completed the study. Anesthesia induction induced a significant decrease in SAP, DAP, and MAP with no effect on HR. Prone position did not induce any significant changes in SAP, MAP, DAP, and HR. A significant difference was found between PPV values in supine (Mean=10.5, SD=4.5) and prone positions (Mean=15.2, SD=7.1) ; t=-4.15 (p<0.001). The mean increase in PPV was 4.7%. Conclusion : Prone position without prior volume expansion induces a significant increase in PPV prior to any modification in arterial blood pressure and heart rate.
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Jabbour et al. (2021) conducted an observational in Elective spinal surgery (n=96). Prone position without volume expansion vs. Supine position was evaluated on Pulse pressure variation (PPV) (MD 4.7, p=<0.001). Prone position without prior volume expansion significantly increased pulse pressure variation compared to supine position (mean 15.2 vs 10.5; P<0.001) prior to any blood pressure changes.
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