The final variable in the initial prognostic model is age. The mean age of 73 years in our study is similar to the 72 years reported by Weiner et al and the 74 years reported by both Plotnick et aln and Goldberger et al. Age had a low weight as a prognostic variable in the multiple regression model, with a 10-year increase in age having an odds ratio of 3.45 (Table 4). Age did not predict in-hospital mortality in the studies of Plotnick et al or Goldberger et al, nor in studies of other severe acute illness. These observations likely reflect the predominant relationship, regardless of age, between severity of organ system failure and mortality.
Thirty-two patients had pulmonary capillary occlusion pressures measured. Values were similar in survivors and nonsurvivors. We believe this reflects patient selection rather than representing the entire study population. Catheters were inserted at an average of 26 hours after hospital admission (hence not reflecting acute pressure elevations), and two thirds of the catheters were placed in patients who did not survive. We believe this reflects the clinicians perceived need for more precise hemodynamic data when in some patients initial therapy was not successful.