Methods of Increasing the Efficiency of Residual Small Bowel Segments: a Preliminary Study.

S MALL BOWEL reversal was first studied by Mall [1}, Miihsam [2] and McClure [3]. The conclusion of these early investigators was that small intestine reversal was fatal to dogs. Within the last ten years interest has been reawakened in surgical procedures designed to delay intestinal transit time [4,5]. Reversal of a small se~nent of terminal ilcmn by these recent investigators has demonstrated that this procedure is compatible with prolonged survival. Protracted survival with maintenance of nutritional balance after massive small bowel resection and end to end anastomosis is frequently difficult or impossible to achieve [6]. The exact length of small bowel necessary to preserve adequate nutrition is variable and depends on several factors, i.e., adequacy of the blood supply, whether the residual segqnent is proxinml jejunum or terminal ileum, the activity and age of the individttal and even perhaps the efficiency of his metabolic processes. Infarction of small bowel may be due to underlying cardiovascular disease, producing thrombosis or embolism in tim superior mesenteric artery (or one of its main branches), intestinal atresia, cardiac decompensation, injury, volvulus, internal herniation or strangulation obstruction clue to adhesions or tmnors. The literature on the subject of small bowel resection, as well as our own experience with $5 per cent small bowel resection in eighty. three mongrel dogs in the experimental surgery laboratories of Presbyterian Medical Center and Children's Hospital, San Francisco, indicate the creation of the following metabolic abnormalities: (1) hypowflemia, (2) metabolic acidosis, (3) megaloblastic anemia, (4) markedly reduced absorption of vitamin Br.,, fats and fat ty acids (Pz~-tagged oleie acid, Dxylose cholesterol) [7]. A considerable portion of neutral fat is absorbed undigested and this process is largely localized in the proximal small bowel. When this area is removed, absorption is slower, but eventually takes place from lower se~nents after enzymatic digestion. The jejunum absorbs all of the carbohydrate and most of the fat and protein before these substances reach the ilemn. Upon resection of the ileum and ile~ecal valve, absorption by the jejunmn is greatly decreased due to "jejunal hurry," i.e., decreased intestinal transit time because of loss of the ileocecal valve. (5) Hypoproteinemia with relative increase in globulins and decrease in albumin. This situation frequently will cause partial anastomotic obstruction and compound the state of malnutrition [8,9]. (6) Hypocalcemia.