Indirect cardiac output assessment in a swine pediatric acute respiratory distress syndrome model

Abstract

Purpose

To investigate the correlation between volume of carbon dioxide elimination (V̇CO₂) and end-tidal carbon dioxide (PETCO₂) with cardiac output (CO) in a swine pediatric acute respiratory distress syndrome (ARDS) model.

Methods

Respiratory and hemodynamic variables were collected from twenty-six mechanically ventilated juvenile pigs under general anesthesia before and after inducing ARDS, using oleic acid infusion.

Results

Prior to ARDS induction, mean (SD) CO, V̇CO₂, PETCO₂, and dead space to tidal volume ratio (V_d/V_t) were 4.16 (1.10) L/min, 103.69 (18.06) ml/min, 40.72 (3.88) mmHg and 0.25 (0.09) respectively. Partial correlation coefficients between average CO, V̇CO₂, and PETCO₂ were 0.44 (95% confidence interval: 0.18–0.69) and 0.50 (0.18–0.74), respectively. After ARDS induction, mean CO, V̇CO₂, PETCO₂, and V_d/V_t were 3.33 (0.97) L/min, 113.71 (22.97) ml/min, 50.17 (9.73) mmHg and 0.40 (0.08). Partial correlations between CO and V̇CO₂ was 0.01 (−0.31 to 0.37) and between CO and PETCO₂ was 0.35 (−0.002 to 0.65).

Conclusion

ARDS may limit the utility of volumetric capnography to monitor CO.