While firm conclusions cannot be drawn, the occlusion pressure data suggest that persistent or refractory left ventricular dysfunction is related to mortality. This is not surprising, since the variables in the regression models are also those that are reflective of left ventricular function.
Another logistic regression model was derived and validated using additional data available 24 hours after intubation; this model identified only two variables — the systolic blood pressure at intubation and the use of vasopressors at 24 hours. This model has a similar predictive value to that using variables at intubation only, and has the advantage of simplicity. As shown in Table 5, the model predicts a mortality of 87 percent if both variables are present, 30 percent with any one variable being present, and only 3 percent if neither is present.
Both of these models were validated in 46 additional patients, with a predictive power similar to that in the original group.
Surprisingly, variables related to severity of respiratory failure did not predict mortality. While Avery et al found that respiratory acidosis was associated with a high mortality, we did not find this to be true in our patients.