abs: CO and Passive Leg Raise Maneuver Anesthetized Dogs

Modified passive leg raise maneuver (PLRM) is a successful volumetric predictor of fluid responsiveness in dogs during experimental induction and correction of hypovolemia using invasive pulmonary artery thermodilution (PACTD) for measuring cardiac output (CO). In this study, other CO methods like minimally-invasive esophageal Doppler (ESD), transesophageal echocardiography (TEE), arterial pressure waveform analysis (APW), and noninvasive electrical velocimetry (EV) were investigated during PLRM in anesthetized dogs.

Methods: Six beagles weighing 8.7 ± 0.1 kg were anesthetized with propofol and isoflurane. All dogs were subjected to four stages in sequential order: baseline (BS), hemorrhage at 30% of total circulating blood volume (H30), autologous blood transfusion (BT), and 20 mL kg-1 colloid bolus (HES). The three stages (H30, BT, and HES) were each induced over 20 minutes. Simultaneous measurements of CO using ESD, TEE, APW, and EV were obtained before PLRM, during PLRM, and after legs were returned to the original position. Bland-Altman analysis and linear regression were used for CO comparisons with PACTD (reference standard).