Test For Completeness Of Vagotomy Research Articles

Effect of proximal gastric vagotomy on insulin- induced gastric H+ and pepsin secretion and serum group I pepsinogens.

The effect of insulin-induced hypoglycemia on serum group I pepsinogens (PG I), gastric H+, and pepsin secretion was studied in 11 duodenal ulcer patients before and 30 days after a proximal gastric vagotomy. The hypoglycemia elicited a significant increase in all the three variables preoperatively but in none of them postoperatively. This suggests that the preoperative increase in serum PG I must be mediated by the vagal nerves. Four of the 11 patients had an incomplete vagotomy by the method of Hollander. Serum PG I did not show any rising tendency in these patients postoperatively. It seems that serum PG I is a less sensitive indicator of the "completeness" of vagotomy than gastric H+ output. The serum PG I response to insulin-induced hypoglycemia can accordingly not be used as a clinical test for completeness of vagotomy.

A non-invasive test for completeness of vagotomy to the pancreas

A new test for completeness of vagotomy to the pancreas was developed. It is based upon the post-absorptive consequences of the absence of cephalic insulin secretion in vagotomized rats. Rats were divided into three groups: in group I, rats were submitted to a truncular vagotomy; in group II, rats underwent a selective gastric vagotomy; group III was a control group. The test was performed when operated rats had recovered from surgery. All rats were fasted from 9 a.m. to 14 a.m. At 14 a.m. (t=0) they were offered 1 ml of a 50% glucose solution and the small amount of urine secreted between t=10 and t=20 was tested for glucose using a reactive strip. Glucose was detected in rats of group I only. This test seems to be a good index of vagotomy to the pancreas; it is easy, inexpensive and non-terminal.

Cephalic insulin response as a test for completeness of vagotomy to the pancreas

Rats received one of four surgical manipulations of the abdominal vagus; either a total vagotomy, a selective dorsal trunk vagotomy, a selective ventral trunk vagotomy or a sham operation. After recovery from the surgery, all rats were fasted overnight and given a saccharine solution the next day. Blood samples were taken 30 min prior to and 3 min after the sampling of the saccharin. Rats with the dorsal vagal trunk intact (those with either a sham lesion or with a selective ventral trunk lesion) had an elevation of immunoreactive insulin after drinking the saccharin whereas those with the dorsal vagal trunk severed did not. This simple procedure is recommended as a test for completeness of vagotomy to the pancreas since it is quick and easy to perform and since it is non-terminal and relatively non-invasive.

Acid response to sham feeding as a test for completeness of vagotomy.

The reproducibility of acid responses to modified sham feeding by the chew-and-spit technique (PAOsh) was investigated in 21 duodenal ulcer (DU) patients 8 to 14 days after vagotomy. Possible relationships between PAOsh and the acid response to 0.2 U of insulin per kilogram body weight were examined (PAOI) in 23 other DU patients 8 to 14 days after vagotomy. PAOsh was reproducible to a high degree (PSpearman less than 0.001, CV 2.9%), and a highly significant relationship was found between PAOsh and PAOI after vagotomy (PSp less than 0.001). PAOsh and PAOI were similar when PAOI was low, whereas a highly incomplete vagotomy according to PAOI was followed by a somewhat lower, but substantial, acid response to sham feeding. The relationship between PAOsh and PAOI permits the recommendation of modified sham feeding as a safe stimulant of acid secretion in quantitative testing of completeness of vagotomy.

Different effects of vagotomy and atropine on hypothalamic stimulation-induced feeding

The effects of subdiaphragmatic vagotomy and atropine administration on thresholds for stimulation-induced feeding and self-stimulation were investigated in male rats. The animals first received permanent bipolar-stimulating electrode implants in the lateral hypothalamus. Once stable thresholds for stimulation-elicited feeding and self-stimulation were obtained, bilateral subdiaphragmatic vagotomies were performed (Experiment 1) or intraperitoneal injections of atropine sulfate were administered (Experiment 2). The first experiment indicated that vagotomy produces a marked disruption of stimulation-elicited feeding but does not interfere with either self-stimulation elicited from the same electrode or stimulation-induced gnawing obtained from comparable lateral hypothalamic sites. Additional observations suggest that a quantitative histological analysis of the vagal trunks can predict the degree of disruption of stimulus-elicited feeding and may provide a discriminating test for completeness of vagotomy. In the second experiment, production of an acute blockade of efferent vagal activity by an injection of atropine sulfate (8 mg/kg) 1 hr before testing had little effect on either feeding or self-stimulation. These results suggest that the vagus may play a significant role in the mediation of stimulation-induced feeding and that the effects of vagotomy on feeding cannot be reproduced by acute cholinergic blockade. The effects of surgical vagotomy on stimulation-induced feeding may reflect interruption of afferent mechanisms, elimination of atropine-refractory efferent systems, or disruption of feeding behavior caused by the sequelae of chronic vagal dysfunction.

Role of vagotomy in duodenal ulcer.

Vagotomy is a dynamic, evolving therapeutic tool rather than the “simple” operation it is sometimes assumed to be. Postoperative ulcer recurrence remains a problem, and the development of a foolproof peroperative test for completeness of vagotomy will be welcome.

The 2DG-neutral red test for completeness of vagotomy

Ever since vagotomy became an important part of modern peptic ulcer surgery, investigators have searched for a test that would reliably indicate the completeness of vagus nerve section. The insulin hypoglycemia test, originally advocated by Hollander [8], has remained the most widely utilized test for the completeness of vagotomy, but despite several modifications it’s reliability has been questioned in a number of reports [6, 13, 141. In addition, the Hollander test has only postoperative application and cannot be used intraoperatively . Two-deoxy-D-glucose (2DG) is a potent vagal stimulant, causing an increase in gastric acid secretion greater than that produced by insulin-induced hypoglycemia [4]. The remarkable safety and low incidence of side effects associated with 2DG have been fully investigated in other studies involving humans [4,9, 121. Neutral red is an azine dye that is secreted by the gastric parietal cells into the stomach lumen [l], but only in the presence of intact vagal innervation to the stomach [lo]. Neutral red has likewise been shown to be safe for human use [7]. The present study is an attempt to use 2DG and neutral red in combination as a test for completeness of vagotomy both intraoperatively and postoperatively.

An endoscopic test for completeness of vagotomy.

After application of Congo red dye to the gastric mucosa, the change in color from red to black can be observed by endoscopy at a pH below 3.0, indicating acid production. In 13 dogs, the time required for complete color change in the parietal cell area was compared preoperatively, after anterior or posterior vagotomy, and following total vagotomy. (1) The interval for complete color change was significantly prolonged in animals with complete vagotomy compared to that in those with no vagotomy. (2) The Congo red test correlated completely with the Hollander test in showing the completeness of vagotomy. Identical results were found in five patients who had had incomplete vagotomy previously. Furthermore, the site of the intact vagal branch could be localized with the method.