Influence of an advance directive on the initiation of life support technology in critically ill cancer patients

Abstract

Objective: To determine whether the presence of an advance directive at admission to an intensive care unit (ICU) influenced the decision to initiate life support therapy in critically ill cancer patients.

Design: Matched-pairs case-control design.

Setting: The University of Texas M. D. Anderson Cancer Center ICU.

Patients: Of 872 patients treated in the ICU from 1994 to 1996, 236 (27%) were identified as having advance directives. One hundred thirty five patients who had advance directives were successfully matched to 135 patients who did not on the basis of type of malignancy, reason for admission to ICU, severity of illness, and age. These pairs comprised the study group.

Interventions: Life-supporting interventions were compared between the matched groups using the McNemar and Wilcoxon matched-pairs signed ranks tests.

Measurements and main results: No significant difference was found in the frequency with which the following interventions were applied in patients with and without advance directives (respectively): mechanical ventilation, 44% vs. 42%; inotropic support, 31% vs. 31%; pulmonary artery catheterization, 11% vs. 12%; cardiopulmonary resuscitation, 7% vs. 12%; and renal dialysis, 3% vs. 7%. There were also no differences in ICU (75% vs. 73%, respectively) or hospital (56% vs. 59%, respectively) survival. More patients with advance directives than those without had do-not-resuscitate orders within the first 72 hrs (19% vs. 11%, p =.046) and patients with advance directives had shorter ICU durations and lower ICU charges than patients without advance directives.

Conclusions: After controlling for type of malignancy, reason for admission to the ICU, severity of illness, and age, the decision to initiate life-supporting interventions did not differ significantly among patients with and without advance directives. The presence of an advance directive, however, may have helped guide decisions earlier regarding duration of therapy and resuscitation status.