THE EVALUATION OF HYPOXIC EVENTS AT THE SURGICAL ICU CONCEPT OF SUPPLY-DEPENDENCY AND ITS EFFECTS ON PROGNOSIS

Abstract

Hypoxic events noticed on 30 critically ill surgical patients who have been monitored at the surgical ICU of the Sixth Surgical Department of Ankara Numune Hospital between March 1990 and November 1991 were evaluated in this study in accordance with the oxygen-monitorization protocol prepared for the ICU patients in February 1990.

Regarding with 30 critically ill surgical patients, no hypoxemia was established in the 8 (26.6%) (Group 1). Among the other 22 patients (73.3%) who had hypoxic attacks, supply independency status (VO₂ being independent on DO₂ was noted on 9 (40.9%) (Group 2-A) and supply-dependency status (VO₂ depending on DO₂) was seen in 13 cases (59%) (Group 2-B).

Monitorization of hypoxemia was carried out only by blood gas analyses on 4 patients. In the others, however, D02, VO₂ VO₂/DO₂ ratios and SV02 were all followed together with blood gas analyses. 11 patients of Group 2-B with ARDS were mechanically ventilated. Common etiological factors in the patients of Group 2-B were defined as sepsis and ARDS.

The mean period of bed occupation of the ICU patients was established to be 1.7 day for Group 1; 4.5 day for Group 2-A and 7.8 day for Group 2-B, respectively.

Surviving periods were also calculated to be 100%, 77%, 7.6% for Group 1, Group 2-A and Group 2-B patients, sequentially.

It has been suggested in this study that supply-dependency of VO₂ which might appear after acute hypoxic events on the ICU patients affects the prognosis directly. The aim of this study is to stress that the intensive monitorization of oxygen transport parameters provides the diagnose of anaerobic metabolism, namely supply-dependency, at the tissue level early. Therefore, optional therapeutic measures can be taken rationally.