Weaning patients with high cardiac output state: influence on central venous pressure and right ventricular stroke work index

Objective

The authors studied the changes in several haemo-dynamic parameters during a weaning trial of a cohort of post-liver transplant patients with a high cardiac output (CO).

Design and setting

An observational, prospective study at a 14-bed medical/surgical ICU.

Materials and methods

Twenty-five patients were enrolled; all presented cardiac index > 4 l/min/m². The following parameters were evaluated: heart rate (HR), mean arterial pressure, central venous pressure (CVP), pulmonary capillary wedge pressure (Pw), CO, systolic pulmonary artery pressure (SPAP) and diastolic pulmonary artery pressure (DPAP), systemic vascular resistance index (SVRI), pulmonary vascular resistance index (PVRI), left ventricular stroke work index (LVSWI) and right ventricular stroke work index (RVSWI). The determinations were performed before disconnection from mechanical ventilation, 30 min after disconnection and 4–6 hours after disconnection.

Results

CVP decreased significantly after disconnection (-24% at 30 min and -20% at 4–6 hours), the CO remained unchanged, inducing a marked and progressive increase in RVSWI. The remaining parameters changed insignificantly. All patients were successfully weaned from mechanical ventilation. The variation of the parameters evaluated is presented in Table 1, with mean values and standard deviation.

Table 1

Conclusions

The weaning from mechanical ventilation in patients with high CO, particularly post-liver transplant patients, induces a significant increase in RVSWI, and a decrease in CVP. From the data presented, the clinical impact of this observation is not clear.