Effect of infusion of nutrient solutions into the ileum on gastrointestinal transit and plasma levels of neurotensin and enteroglucagon

The small bowel transit time of 100 ml of lactulose solution infused at the ligament of Treitz was measured by breath hydrogen excretion in paired studies carried out in 43 healthy volunteers during infusion (1.2 ml/min) of equal volumes (100 ml) of isotonic solutions of either fat emulsion (Intralipid, Prosparol, or Calogen), protein hydrolysate, glucose, or saline into either the jejunum (90 cm from the teeth), ileum (205 cm from the teeth), or colon (350 or 400 cm from the teeth). Ileal infusion of Intralipid or protein hydrolysate resulted in significant delays in small bowel transit time (125 +/- 21 min and 71 +/- 11 min, respectively) compared with infusion of saline (50 +/- 3 min; p less than 0.02 and p less than 0.05). These delays were not associated with any significant alteration in plasma levels of neurotensin or enteroglucagon. Small bowel transit time was unaffected by infusion of nutrients into the colon or jejunum, although jejunal infusion of Intralipid increased the plasma levels of enteroglucagon and neurotensin (p less than 0.01 and p less than 0.02, respectively) after the start of lactulose infusion. In a separate series of paired experiments, infusion of Intralipid into the ileum in 5 volunteers significantly delayed the transit of a solid test meal labeled with 25 microCi of 99mTc-sulfur colloid through both the stomach and small intestine. These data support the existence of a mechanism whereby the presence of unabsorbed food in the ileum may enhance absorption by delaying the passage of food through the small intestine.

Elevation of postoperative plasma amino acid concentrations by immediate full enteral nutrition

Serum amino acid (AA) levels were determined for 18 cholecystectomy patients who had preserved and immediately utilized G-I function for absorption of 3,000 kcal/day elemental diet. Ten were given 132 gm AA/day; eight were given only 66 gm AA/day. Historical controls were 27 comparable patients who had received conventional hypocaloric intravenous (IV) regimens. Unfed patients' branched chain AAs (BCAAs) + TYR were depressed initially, then rebounded by day 3 or 4. Their glucogenic AAs were still depressed after 72 hours. Complete restoration of the basal pattern required five to ten days. Fully nourished patients maintained basal levels of all AAs on day 1. Every AA rose above basal, some with statistical significance as early as day 2. Moderately fed patients had BCAA depression, but for only 24 hours. LEU, ILE, VAL, TYR, MET, ASP, LYS, and ARG had already returned to basal levels on day 2, while the remaining AAs were much less depressed than in the unfed controls. All fed patients were discharged uneventfully 24-48 hours postcholecystectomy. The positive protein balance and elevated AA levels correlate with enhanced wound healing, host sepsis resistance, and shortened hospitalization.

Malabsorption associated with extreme malnutrition: importance of replacing plasma albumin

An elderly man had severe malnutrition secondary to esophagogastric obstruction by carcinoma. Tube feeding resulted in diarrhea. Malabsorption ceased, and full enteral nutrition with elemental diet was tolerated immediately following albumin infusion. Clinical and experimental data indicate that this role for albumin, in enteral absorption, is related to its oncotic properties. Severe deficits can be reversed rapidly, simultaneously restoring the plasma concentration and GI function.

Maintenance of GI function after bowel surgery and immediate enteral full nutrition. I. Doubling of canine colorectal anastomotic bursting pressure and intestinal wound mature collagen content

Following either standardized stapled resection of an ileal blind loop terminus (17 beagles) or construction of a colorectal anastomosis (10 beagles), half the subjects immediately were fed an elemental diet (Vivonex HN). Gastrointestinal (GI) motility and absorption were maintained by exclusion of swallowed air. Controls received the same rate of feeding solution containing only the electrolyte components. Four days postoperatively, the fed beagle's colorectal anastomosis had over double the bursting pressure of the control, 303 +/- 46 mm Hg (p less than 0.001). At this time, the mature collagen content of the fed subjects' ileal wound was undiminished from that of normal ileum 2,223 +/- 336 versus 2,250 +/- 577, contrasting with the 45% decrease of this structural component (OHP) in the wounds of the unfed controls, 1,237 +/- 820 microgram/g of tissue (p less than 0.001). Similarly, the wounds of fed but not unfed subjects had a doubling (p less than 0.001) in concentration of collagen precursors and "new" collagen. The "catabolic" and "lag" phases, as noted in unfed experimental animals, appeared to be reflections of the relative starvation that accompanied the intestinal wounding. With maintenance of GI function and immediate full enteral nutrition, "accelerated healing" was noted relative to the previously considered "norm".

The pentose phosphate pathway in brain during development

Sprague-Dawley rats were delivered in our laboratory and decapitated at ages varying between 1 and 60 days. The concentrations of 6-phosphogluconate in extracts of the brain were determined in these litters and in adult rats. The highest of 6-phosphogluconate was seen in brains of 3-day-old rats when it was at that age more than six times the adult level. Turnover rates for this same compound were determined by an in vitro technique at ages 1, 3 and 12 days and in the adult. We conclude that the pentose phosphate pathway is more active in rat brain during early development than in the adult, with a peak occurring at 3 days of life, indicating a possible link to nucleic acid synthesis.

Postsurgical decompression and immediate elemental feeding

The paralytic ileus, poor nutritional state, and related complications that often develop following serious serious abdominal surgery have traditionally been accepted as unavoidable. Now, a nasogastric decompression and feeding tube is availabe that usually prevents paralytic ileus and also provides a complete liquid diet starting immedicately after the operation, thus speeding wound healing and recivery.

Abdominal decompression: increased efficency by esophageal aspiration utilizing a new nasogastric tube

Gastric aspiration alone utilizing either a Levin-type nasogastric tube or a gastrostomy tube is inefficient. The esophagus proved to be a more efficient supplemental site for aspiration of a swallowed bolus. For thirty-one patients, esophagogastric aspiration proved to be approximately twelve times as efficient as aspiration via a Levin-type tube for twenty-four patients or a gastrostomy tube in five patients (residual activity, of 3,35, and 42 per cent, respectively). Radiographic studies of a volunteer swallowing barium with each type of nasogastric tube in place showed efficient removal of the contrast agent by esophageal aspiration. With the Levin-type tube, the bolus promptly traversed the stomach and entered the duodenum along parallel channels remote from the x-ray -visualized gastric tube. Efficient postoperative exclusion of swallowed air clinically and experimentally by esophageal aspiration permits more rapid return of gastrointestinal function and full nutrition and perhaps shortened hospitalization.

The centrineurogenic etiology of the respiratory distress syndrome: induction by isolated cerebral hypoxemia and prevention by unilateral pulmonary denervation

Twenty-eight anemic control dogs were subjected to isolated cerebral hypoxemic (PO2,35+/-5 mm Hg) perfusion for 2 hours. All were found to have functional pulmonary impairment. Two hours later, twenty were sacrificed and found to have the bilateral anatomic complex of the respiratory distress syndrome (RDS). All those not sacrificed expired within 20 hours with progressive respiratory distress and at autopsy had the bilateral anatomic complex. Twenty-three beagles with chronic denervation (autotransplantation) of the left lung also were subjected to the 2 hour isolated cerebral arterial hypoxemic perfusion. Minimal pulmonary functional impairment was measurable in all. Ten of sixteen were long-term survivors. The six that succumbed did not appear to suffer respiratory deaths. These six, as well as seven sacrificed 2 hours after perfusion, had the anatomic complex of RDS in the normally innervated right lungs. However, the denervated left lungs were anatomically normal. These findings are offered as additional evidence that RDS has a centrineurogenic etiology. We postulate the following sequence: "shock" causes cerebral (probably hypothalamic) cellular oxygen deprivation and dysfunction; there is autonomically mediated, increased resistance of the pulmonary venules ("postcapillary sphincters"); this leads to capillary hypertension, congestion, hemorrhage, edema, surfactant inactivation, and atelectasis. Pulmonary denervation blocks this sequence and protects the lung.

Central nervous system control of pulmonary vascular resistance; effect of anesthesia after unilateral denervation

Seven beagles were subjected to left pulmonary denervation (autotransplantation) and allowed one to two months for complete recovery. The relative resistances of each dog's pair of lungs were determined by the distribution of 99mTc microspheres delivered intravenously while the subject was awake and then under barbiturate anesthesia. In each case, relative blood flow to the right lung increased at the expense of flow to the left. This is interpreted as a direct decrease in pulmonary vascular resistance on the right under the effects of anesthesia. The implications of such central nervous system control of pulmonary vascular resistance was discussed in relation to the pathophysiology of the respiratory distress syndrome.

The centrineurogenic etiology of the respiratory distress syndrome: protection by unilateral chronic pulmonary denervation in hemorrhagic shock

Anemic beagles were subjected to 40 mm Hg hemorrhagic shock for 2 hours, which uniformly induced the pulmonary lesions of the "respiratory distress syndrome" (RDS) bilaterally in all six controls. For six subjects with complete denervation of the left lung 2 months previously, the shock regimen induced the lesions in the normally innervated right lungs; all reimplanted, denervated left lungs remained anatomically intact. This is presented as additional evidence for a centrineurogenic etiology for RDS.

The centineurogenic etiology of the respiratory distress syndrome. Protection afforded by anemia and pulmonary denervation against lung lesions of oxygen toxicity

For beagles respiring 100 per cent oxygen at ambient pressure, anemia protected against the development of the lung lesions of oxygen toxicity. Similarly, unilateral pulmonary denervation was protective of the affected lung but not of the normally innervated, contralateral lung. This indicates that the lung lesions are triggered by the toxic effect of elevated PO2 at a remote site, most likely the sensitive central nervous system.

Viable lymphocytes in frozen washed blood

Samples of glycerolized, frozen, packed cells, were washed by each of three systems and then were cultrued for viable lymphocytes using the short-term culture method. Of the 39 samples, 17 (43.6%) showed definite evidence of growth of lymphocytes. Of the 17, 11(64.7%) were washed by Elutramatic, two (11.8%) by Haemonetics, and four (23.5%) by IBM. The 4 C prefreeze (two to five days) as well as the -80 C (21 To 40 days) storage times were the same for both positive and negative specimens. In all samples, clumps of distorted granulocytes with pyknotic nuclei were seen in addition to a number of well-preserved mononucleated white cells. In the 17 specimens which showed growth, incorporation of 3H-thymidine was seen only in the PHA-induced blast cells; typical mitotic figures were seen in some cultures. These observations demonstrate that lymphocytes remain viable in frozen blood stored at -80 C up to 40 days. The significant difference in removal of viable lymphocytes noted in specimens washed by different instruments requires further evaluation.

Dilutional re-expansion with crystalloid after massive hemorrahage: saline versus balanced electrolyte solution for maintenance of normal blood volume and arterial pH

When administered in sufficient amounts, normal saline and Lactated Ringer's Solution are equally effective in maintaining adequate circulatory volumes despite severe blood loss and resultant hypoproteinemia. Arterial pH is maintained within normal limits when either solution is used for resuscitation provided the circulatory volume has been re-expanded to adequate levels for good tissue perfusion and support of aerobic metabolism. The pH of the infused solutions has no effect on blood pH under these circumstances. Fourteen splenectomized dogs were subjected to continuous hemorrhage and simultaneous replacement with either normal saline or Lactated Ringer's Solution. The cumulative replacement volume ratio necessary for equilibration after 61% RBC depletion was 7:1 crystalloid to the whole "undiluted" blood shed, in both groups. Indicators of pulmonary-circulatory physiology remained stable within normal limits. Arterial pH did not exhibit significant changes from normal values after resuscitation with NS or LRS. The group infused with LRS exhibited no change in arterial pH, 7.40 plus or minus .07 initial and 7.40 plus or minus .09 final; in the group with NS replacement a slight decrease from control was noted, 7.40 plus or minus .07 initial and 7.36 plus or minus .06 final. These differences, however, are not statistically significant. Of the 14 subjects, 13 were long-term survivors. The one death was associated with a technical mishap shortly after completion of the experiment. Because banked blood imposes a "net" alkaline metabolic load (sodium citrate), patients expected to be transfused with large volumes of stored blood might be better resuscited with normal salin than with Ringer's Lactate Soultions, to minimize or avert the otherwise resultant metabolic alkalosis.

Progressive hypovolemia leading to shock after continuous hemorrhage and 3:1 crystalloid replacement

Dogs subjected to arterial hemorrhage and infused with 3:1 volumes of lactated Ringer's solution became progressively hypovolemic, to the point of frank shock. Stability and normovolemia were restored only after additional fluid delivery, in a net ratio of 8:1. These were the mathematically predicted values that satisfied Starling's hypothesis.

Cerebral etiology of the acute respiratory distress syndrome: diphenylhydantoin prophylaxis

Beagles and rats were subjected to hemorrhage regimens that induced the pulmonary complex of the Acute Respiratory Distress Syndrome (ARDS) in 6:6 dogs and 7:8 rats. Pretreatment with diphenylhydantoin (DPH), 5 mg/kg 1-2 hours preceding hemorrhage, resulted in complete prevention of the lung lesions in 8:8 dogs. (P smaller than 0.005). It also provided significant (P smaller than 0.01) protection to 8:11 rats. We offer this as circumstantial evidence that the ARDS has a centrineurogenic etiology.