Continuous and intermittent cardiac output measurement: pulmonary artery catheter vs aortic transpulmonary technique

Introduction

We compared two methods of intermittent cardiac output measurements: pulmonary artery catheter (COpa) (Vigilance system SvO₂/CCO, Baxter Edwards Laboratories, Irvine, CA, USA), regarded as the current clinical standard, and an aortic transpulmonary thermodilution technique (COart) performed with the PiCCO System (Pulsion Medical System, Munich, Germany), and also compared the continuous thermodilution technique (CCO), the continuous pulse contour analysis cardiac output (PCCO) versus COpa in patients during lung transplantation.

Methods

Measurements were made in 49 patients at six stages between the induction of anaesthesia and the end of surgery. Statistical analysis used the method described by Bland and Altman.

Results

We found close agreement between the techniques. Mean bias between COart and COpa was 0.21 l min^-1 (2 SD of differences between methods = 1.6 l min^-1). Mean bias between CCO and COpa and PCCO and COpa was 0.16 l min^-1 (2 SD= 1.40 l min^-1) and 0.09 l min^-1 (2 SD = 1.39 l min^-1) respectively (see Fig 1).

Figure 1

Conclusions

Measurements with the aortic transpulmonary thermodilution technique give continuous and intermittent values that agree with the pulmonary thermodilution method. Anyway, continuous CO data obtained with PAC reflect accurately the clinical standard thermodilution COpa.