Variations in pulse oximetry plethysmographic waveform amplitude induced by passive leg raising in spontaneously breathing volunteers - 09/08/11

Doi : 10.1016/j.ajem.2006.11.035

Samuel Delerme, MD ^a, Robin Renault, MD ^a, Yannick Le Manach, MD ^b, Virginie Lvovschi, MD ^a, Mouhssine Bendahou, MD ^a, Bruno Riou, MD, PhD ^a, Patrick Ray, MD ^a,^⁎
^a Department of Emergency Medicine and Surgery, CHU Pitié-Salpêtrière, Assitance Publique-Hôpitaux de Paris, Université Pierre et Marie Curie–Paris, 75013 Paris, France
^b Department of Anesthesiology, CHU Pitié-Salpêtrière, Assitance Publique-Hôpitaux de Paris, Université Pierre et Marie Curie–Paris, 75013 Paris, France

^⁎Corresponding author. Service d'Accueil des Urgences, Groupe Hospitalier Pitié-Salpêtrière, 75013 Paris, France. Tel.: +33 1 42 17 72 49; fax: +33 1 42 17 72 64.

Abstract

Purpose

Noninvasive methods that could predict preload responsiveness are lacking. Our objective was to evaluate variations in pulse oximetry plethysmographic (POP) waveform amplitude (ΔPOP) induced by passive leg raising (PLR).

Methods

We attached a pulse oximeter to the middle finger of 25 spontaneously breathing volunteers at several time points: baseline (ie, semirecumbent position), during PLR at 60° while each subject's trunk was lowered in a supine position at 1 minute, and after putting the patient back in the semirecumbent position (5-minute rest). Heart rate, noninvasive arterial pressures (mean arterial pressure and pulse pressure), maximal POP (POP_max), minimal POP (POP_min), and ΔPOP defined as [POP_max − POP_min]/[(POP_max + POP_min)/2] were recorded using a monitor.

Results

Heart rate, mean arterial pressure, pulse pressure, POP_max, and POP_min values were not different at baseline, during PLR at 1 minute, and after the 5-minute rest (repeated-measures analysis of variance). The median ΔPOP significantly decreased from 16% (95% confidence interval = 11%-23%) to 11% (95% confidence interval = 8%-14%) (P < .05) and then increased to 13% (95% confidence interval = 10%-21%) after the 5-minute rest (P = nonsignificant).

Conclusion

Passive leg raising induces a significant decrease in ΔPOP among spontaneously breathing volunteers.

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Plan

Introduction

Materials and methods

Respiratory variations in POP waveform amplitude analysis

☆	Authors' contributions: PR and SD conceived the study, analyzed the curves, collected data, performed the statistical analysis, and drafted the manuscript. RR, VL, and MB collected data. YL participated in the statistical analysis. BR helped draft the manuscript. All authors read and approved the final manuscript.
☆☆	Datascope and Masimo provided the instruments used in this study free of charge.