The development of the balloon-tipped flow-directed pulmonary artery (PA) catheter by Swan and colleagues has led to the widespread application of invasive hemodynamic monitoring in critically ill patients. Although criteria for therapy have been tacitly assumed to be normal values, increased hemodynamic and oxygen transport variables observed in survivors raise questions regarding therapeutic goals. Therapeutic goals for cardiac patients whose other vital organs are unimpaired may be different from those of the postoperative general surgical patient whose cardiac function is normal but whose metabolic demands are increased. The problems of the noncardiac general surgical patient may be of interest to the medical consultant and to the internist who inserts PA catheters to monitor these patients. in detail
The critically ill surgical patient provides a unique opportunity to observe the development of one particular type of shock because elective surgical patients may be studied in the preoperative state, during the development of their circulatory crisis, and in the subsequent period where characteristic patterns of recovery or death evolve. Bland et al described the temporal sequence of hemodynamic and oxygen transport patterns in surviving and nonsurviving general surgical patients and from this physiologic database developed an empiric heuristic physiologic algorithm which then was demonstrated to satisfactorily predict outcome prospectively. Therapeutic goals were developed from this predictor and the median values of the survivors. Predictors based on the survivors’ values were shown to have a high degree of accuracy in prospective testing. Hankeln et al have recently confirmed that the survival and nonsurvival patterns are predictably associated with outcome in a wider clinical mix and with less rigid time constraints.
The present study tests the hypothesis that the physiologic pattern empirically defined by the survivors may be the appropriate therapeutic goals for high-risk critically ill postoperative patients. In two prospective clinical trials, the outcomes of patients whose therapeutic goals were to maintain normal hemodynamic values were compared with those whose goals were to attain the supranormal values empirically observed in critically ill postoperative survivors. In the first prospective series, patients were allocated by service; in the second prospective series patients were randomized preoperatively to either central venous or PA catheterizations, as well as to the two different therapeutic strategies. The two series are considered separately as they are directed to different problems.
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