Discordância entre a análise de contorno de pulso e a termodiluição pulmonar para mensuração do débito cardíaco durante alterações no tônus vascular em cães anestesiados com isofluorano

Cardiac output measured by pulse contour analysis (COPCA) could present errors during hemodynamic instability. This study evaluated if changes in SVR could affect agreement between COPCA and cardiac output measured by pulmonary thermodilution (COP) in dogs. The COP and transpulmonary thermodilution cardiac output (COTP) were measured in eight adult isoflurane-anesthetized dogs (25 ± 3.6 kg) via thermodilution catheters positioned in the pulmonary and femoral arteries, respectively. After calibration of COPCA using COTP, constant rate infusions (CRIs) of phenylephrine (1.0 μg/kg/min, IV) or nitroprusside (1.0 μg/kg/min, IV) conditions were randomly administered. Three serial measurements of COP and COPCA were performed 15 minutes after commencing each CRI. After measurements were concluded, the CRI was stopped and a 15-minute washout-period was allowed before commencing the new CRI. Data were analyzed by the Bland-Altman method. The percentage error (2 x SD of bias between methods / average COP x 100) was predefined as 30% observed during nitroprusside administration suggests that the COPCA without recalibration is not reliable method during vasodilatory states.