Hypothesis: “Feeding intolerance” results from localized proximal G-I distention caused by total inflow to the feeding site (feedings + secretions) exceeding peristaltic outflow. Vagal reflexes initiate a “downhill spiral” that paralyzes the already sluggish gut, leading to generalized distention, poor respiratory mechanics, etc.
Methods: We studied consecutive surgical patients (160 cholecystectomy, 17 colectomy, and 3 esophagectomy). All were immediately fed elemental diet @ ≥100 kcal/hour into the distal duodenum. Efficient aspiration 7 cm proximal to the feeding site removed all air and any excess liquid (confirmed by X-ray). Colectomy patients had contrast X-ray motility study.Serial analyses were conducted for serum amino acids and glucose; aspirate was assayed for removed foodstuff; hourly nitrogen balances were determined.Cholecystectomy aspirate was replaced by IV fluids. Colectomy patients had degassed aspirate “refed” manually. Esophagectomy patients were “refed” automatically, in effect performing a “check for residual” every 30 seconds.
Results: No adverse events were attributable to the feeding-decompression regimens. Aspirate was free of feeding solution within two hours; serum levels of amino acids had risen above basal; glucose was >150 mg/dl. Most (even non-diabetics) required supplemental insulin to maintain euglycemia. Requirement for insulin dependent diabetics rose markedly during those initial 24 hours. All except esophagectomy patients (still on respiratory support) tolerated their usual diets by 24 hours after surgery without supplemental insulin.Every cholecystectomy patient (160:160) had a cathartic induced bowel movement, and was discharged within 24 hours of surgery. One patient (1:160) died of a pulmonary embolus 29 days later. One patient (1:160) developed an abdominal infection. One patients (1:160) was re-admitted for percutaneous aspiration of a sterile biloma. One patient (1:160) was re-admitted for a transient ischemic attack. Normal motility was noted within hours of colectomy. Net absorption was >2,300 kcal the initial 24 hours. Contrast traversed secure anastomoses to exit in a bowel movement within 48 hours, and all achieved positive protein balance within 2 - 24 hours. Four patients were discharged uneventfully 24 hours after colectomy. “Refed” patients had only 100-200 ml/day of aspirate discarded, containing <100 ml of elemental diet.
Conclusions: “Feeding intolerance” appears to be triggered by G-I distention at the intestinal feeding site. A regimen that titrates inflow to match peristaltic outflow prevents this complication, while permitting more rapid achievement of nutritional goals.