Choice of abdominal operative incision in the obese patient: a study using blood gas measurements.

Although many factors may influence the choice of the operative incision, physiologic safety in terms of the degree of postoperative hypoxemia should be considered. No data currently exist to delineate in markedly obese patients the effect of the operative incision on the extent or duration of this hypoxemia. Fifty-four consecutive patients of both sexes, scheduled for elective jejunoileal bypass for morbid exogenous obesity, were studied. In 23 patients the operation was performed through a transverse incision and in 25 patients through a vertical incision. In 6 patients, cholecystectomy was also performed in addition to the jejunoileal bypass. Postoperatively there was a significant fall in PAO2 both in the transverse and vertical incision groups and this continued through day 4. On day 5 statistically significant hypoxemia was present only in the vertical incision group. In addition, the decrease in PaO2 was significantly greater on days 4 and 5 in the vertical group than in the transverse group. On days 2 and 3 again the mean decrease in PaO2 was greater in the vertical group but this was not statistically significant. The effect of added cholecystectomy on PaO2 was studied in 6 women with midline incisions. The results were compared with 6 subjects who had small bowel bypass without cholecystectomy and who were matched for incision, age weight, girth/height ratio, weight/height ratio, smoking habit, and percentage of predicted ERV. In both groups there was a significant fall of PAO2 from day 1 through day 4, but there was no significant difference between the two groups. Although the numbers studied were small, these limited results would suggest that the type of incesion rather than the intraoperative procedure is the important factor in determining postoperative PAO2 changes. These studies also suggest that in patients with an increased potential for postoperative hypoxemia (i.e., markedly obese), the transverse abdominal approach shoudl always be seriously considered.