Diferencia veno-arterial de dióxido de carbono como predictor de gasto cardiaco disminuido en modelo experimental.

Resumen

VENO-ARTERIAL PCO₂ DIFFERENCE TO PREDICT LOW CARDIAC OUTPUT IN AN EXPERIMENTAL PIGLET MODEL

Background: Cardiac output (CO) measurement is not a standard of care for critically ill children, but it can be estimated by indirect methods such as veno-arterial pCO₂ difference (?VACO₂). Aim: To determine the correlation between CO and ?VACO₂ and evaluate the usefulness of ?VACO₂ in the diagnosis of low CO in an experimental pediatric model. Material and methods: Thirty piglets weighing 4.8±0.35 kg, were anesthetized and monitored with transpulmonary thermodilution. Lung injury was induced with tracheal instillation of Tween 20®. Serial measurements of central venous and arterial blood gases, as well as CO, were obtained at baseline, 1, 2 and 4 h after lung injury induction. Low cardiac output (LCO) was defined as CO lower than 2.5 L/min/m².  Results: There was an inverse correlation between CO and ?VACO² (r= -0.36, p< 0.01).  ?VACO₂ was 14 ± 8 mmHg in LCO state and 8 ± 6 mmHg when this condition was not present (p< 0.01).  Area under the receiver operating characteristic (ROC) curves of ?VACO₂ and LCO state was 0.78 (0.68-0.86). The best cut-point was 8.9 mmHg to determine LCO with a sensibility 0.78, specificity 0.7, positive predictive value 0.27 and negative predictive value 0.96. Conclusions: In this model there was an inverse correlation between ?VACO₂ and CO. The best cutoff value to discard LCO was ?VACO₂ of 8.9 mmHg, indicating that under this value the presence of LCO is very unlikely.