About cardiac output assessment in pulmonary hypertension

Determination of cardiac output (CO) is a primordial hemodynamic data in the diagnosis and the management of pulmonary hypertension (PH). Its value directly influences the calculation of pulmonary vascular resistance (PVR). Aim To compare two methods for cardiac output measurements and to calculate the consequences on the calculation of PVR. Methods 99 patients underwent right heart catheterism (RHC). Right atrial and mean pulmonary artery pressure (RAp and MPAp, mmHg) were measured. Cardiac output (CO, l/min) was measured by the direct Fick method applied on oxgen and by the transpulmonary thermodilution method. Pulmoray vascular resistance (PVR, Wood Unit) were also calculated as follow PVR=(MPAp-RAp)/CO A significant but wide correlation exists between the two methods (r=0.62; p Conclusion The thermodilution method underestimates absolute values of CO and overestimates the calculation of PVR especially when resistance increase.