Passive leg raising during cardiopulmonary resuscitation in out-of-hospital cardiac arrest--does it improve circulation and outcome?

Abstract

Background: Passive leg raising (PLR), to augment the artificial circulation, was deleted from cardiopulmonary resuscitation (CPR) guidelines in 1992. Increases in end-tidal carbon dioxide (P(ET)CO(2)) during CPR have been associated with increased pulmonary blood flow reflecting cardiac output. Measurements of P(ET)CO(2) after PLR might therefore increase our understanding of its potential value in CPR. We also observed the alteration in P(ET)CO(2) in relation to the return of spontaneous circulation (ROSC) and no ROSC.

Methods and results: The P(ET)CO(2) was measured, subsequent to intubation, in 126 patients suffering an out-of-hospital cardiac arrest (OHCA), during 15 min or until ROSC. Forty-four patients were selected by the study protocol to PLR 35 cm; 21 patients received manual chest compressions and 23 mechanical compressions. The PLR was initiated during uninterrupted CPR, 5 min from the start of P(ET)CO(2) measurements. During PLR, an increase in P(ET)CO(2) was found in all 44 patients within 15 s (p=0.003), 45 s (p=0.002) and 75 s (p=0.0001). Survival to hospital discharge was 7% among patients with PLR and 1% among those without PLR (p=0.12). Among patients experiencing ROSC (60 of 126), we found a marked increase in P(ET)CO(2) 1 min before the detection of a palpable pulse.

Conclusion: Since PLR during CPR appears to increase P(ET)CO(2) after OHCA, larger studies are needed to evaluate its potential effects on survival. Further, the measurement of P(ET)CO(2) could help to minimise the hands-off periods and pulse checks.