Comparison of two methods for enhanced continuous circulatory monitoring in patients with septic shock

Objective: To compare a modified pulmonary artery catheter (PAC) and pulse-contour analysis by the PiCCO (Pulsion Medical Systems, Munich, Germany) system for continuous assessment of cardiac output in patients with septic shock. In addition, to assess the relationships between an index of global end-diastolic volume (GEDV) derived by the PiCCO system with traditional PAC-derived indicators of filling: central venous pressure; pulmonary artery occlusion pressure; and right ventricular end- diastolic volume (RVEDV). Design: Prospective cohort study. Setting: Surgical intensive care unit of a university hospital. Patients and participants: 14 patients with septic shock. Interventions: None. Measurements and results: A significant correlation was found between continuous cardiac output by PAC ( CCOPAC) and by pulse-contour analysis (r(2) = 0.714, p < 0.0001), accompanied by a bias of 0.11 min(-1) and a precision of 2.71 min(-1). The correlation between CCOPAC and cardiac output measured by transcardiopulmonary thermodilution was also significant (r(2) = 0.781, < 0.0001). There was a bias for the two methods of 0.21 min(-1), and a precision of 2.21 min(-1). The GEDV showed no correlation with central venous pressure, pulmonary artery occlusion pressure, or RVEDV. Conclusion: In patients with septic shock, the averaged bias in continuous measurement of cardiac output by both a modified pulmonary artery catheter and pulse- contour analysis was small, but variability was large. No correlation was found between GEDV and RVEDV. The clinical importance of different cardiac filling parameters needs further investigation.