Optimization of cardiac preload during laparoscopic donor nephrectomy: a preliminary study of central venous pressure versus esophageal Doppler monitoring.

BACKGROUND: While the popularity of laparoscopic donor nephrectomy (LDN) has increased, concern persists about the potential deleterious effects of pneumoperitoneum on renal function. Thus, preload optimization with vigorous intravenous hydration has been recommended. The purpose of this study was to compare central venous pressure (CVP) monitoring with a noninvasive measure of cardiac preload (esophageal Doppler) during LDN. METHODS: Thirteen patients were studied. Following induction of general anesthesia, a Doppler probe was inserted in the lower third of the esophagus to measure flow time corrected for heart rate (FTc), which is an index of preload. In 10 patients, a catheter was placed in the right internal jugular vein and CVP measured. CVP and FTc were measured at baseline in the supine and right lateral decubitus positions, then 15 and 60 min after the establishment of CO(2) pneumoperitoneum (12-15 mmHg). IV fluids were increased if the FTc fell below 300 msec. Results are expressed as means (+/-SD). Data were analyzed using repeated measures ANOVA. RESULTS: Lateral positioning and pneumoperitoneum significantly increased CVP from baseline ( p < 0.01), while the FTc did not change ( p = 0.57). After 60 min of pneumoperitoneum, the FTc was <300 msec in only one patient. CONCLUSION: CVP is not an accurate guide for administration of IV fluids during LDN. Esophageal Doppler monitoring can be used to noninvasively follow changes in preload during LDN and is worthy of further study.

Percutaneous endoscopic gastrostomy: indications and results.

Patients requiring feeding gastrostomies are often poor risks for either laparotomy or general anesthesia. Percutaneous endoscopic gastrostomy can be performed at the bedside by a surgeon-endoscopist and with minimal sedation. The authors performed this procedure on 45 patients ranging in age from 17 to 88 years. The procedure was indicated for neurologic disorders in 34 patients, head and neck tumours in 2, failure to thrive in 4, esophageal obstruction from lung cancer in 1 and tracheostomy for multisystem failure or trauma and sepsis in 4. In three cases the procedure could not be performed because the stomach could not be intubated. In 29 cases local anesthesia and sedation (diazepam and meperidine) were used, but in 16 cases general anesthesia with hyperventilation was preferred. The mean operative time was 32 minutes, decreasing with experience so that the current mean operative time for the last nine cases was 23 minutes. Feeding was begun on day 1 after operation in most patients and on day 2 in others. Complications included tube displacement in three patients, superficial infection at the site of the tube insertion in three (not requiring drainage or tube removal) and asymptomatic pneumoperitoneum in one patient. These complications all occurred early in the series. No patient suffered paralytic ileus, vomiting, aspiration or significant leaking around the tube. In the authors' opinion percutaneous endoscopic gastrostomy is the preferred method for placement of a feeding gastrostomy. It can be performed rapidly with minimal stress in high-risk patients.

Release of cholecystokinin in response to food and intraduodenal fat in pigs, dogs and man.

The present study was done to compare endogenous cholecystokinin-33 release in response to physiologic stimuli (meal, fat) in pigs, dogs and man. Plasma levels of cholecystokinin-33 were monitored using a radioimmunoassay for cholecystokinin which detects only cholecystokinin-33 and cholecystokinin-39. Ingestion of a meal caused release of cholecystokinin-33 within five, 20 and 120 minutes in man, pigs and dogs, respectively. Intraduodenal administration of corn oil resulted in a significant release of cholecystokinin-33 within 20 minutes in dogs, pigs and man.

Colonic inhibition of cholecystokinin release and pancreatic protein secretion in dogs.

We have shown that the colon is capable of exerting profound inhibition on pancreatic enzyme secretion. This inhibition is brought about, at least in part, by significant suppression of release of cholecystokinin. Pancreatic polypeptide does not appear to be involved in colonic inhibition of pancreatic secretion.

Correlation between release of cholecystokinin and contraction of the gallbladder in patients with gallstones.

The role of endogenously released cholecystokinin (CCK) in mediating gallblader (GB) contraction was evaluated in 12 normal volunteers and 24 patients with gallstones (11 additional gallstone patients were excluded because of failure of adequate ultrasonographic visualization). CCK concentrations before and after oral administration of fat (Lipomul((R))) were measured by a specific radioimmunoassay. CCK release was correlated with changes in GB volume determined simultaneously by ultrasonography. On the basis of gallbladder contraction and operative findings, gallstone patients were divided into "contractors" (14), "noncontractors" (6), and "hydrops" (4). Lipomul caused prompt release of CCK in normal volunteers and all groups of gallstone patients. The changes (basal to peak) in plasma CCK (pg/ml) for the different groups were as follows: normal volunteers (108 +/- 9 to 200 +/- 16), contractors (77 +/- 10 to 128 +/- 13), noncontractors (59 +/- 7 to 159 +/- 38), and hydrops (43 +/- 5 to 113 +/- 47). The total integrated output of CCK (0-60 min) was greater in normal volunteers (3975 +/- 762 pg-min/ml) than in contractors (1530 +/- 567 pg-min/ml). Lipomul caused similar GB contraction in normal volunteers and contractors (from basal volumes to maximal contraction); these changes were from 19.5 +/- 2.3 ml to 5.6 +/- 1.0 ml in normal volunteers, and from 19.6 +/- 3.2 to 5.2 +/- 1.0 in contractors. Plasma concentrations of CCK and GB volume were highly correlated in the 12 normal volunteers (r = -0.89, p < 0.01) and in the 14 contractors (r= -0.99, p < 0.01)), but the GB was significantly (p < 0.01) more sensitive to changes in plasma CCK in the gallstone contractors than in the normal volunteers. The authors suggest that there may be two groups of gallstone patients, noncontractors and contractors. Stasis may be important in the pathogenesis of gallstones in the noncontractors, whereas in contractors, the authors speculate that an abnormality in the CCK-gallbladder relationship (characterized by diminished CCK release and increased GB sensitivity to CCK) may be involved in the evolution of the disease.

Recurrent obstipation as a complication of partial pancreatectomy for non-beta cell adenoma of the pancreas.

Verner and Morrison, in 1958, reported non-insulin-secreting tumours of the pancreas that were associated with a syndrome of refractory diarrhea, achlorhydria and hypokalemia. Surgical resection of such tumours results in rebound acid hypersecretion and cessation of the watery diarrhea. The authors report the case of an 84-year-old man who had three of the four major criteria for diagnosis of the Verner Morrison syndrome. Hypokalemia was absent, but this was possibly due to the large doses of potassium chloride that he was taking in conjunction with diuretics. After resection of the tumour severe obstipation with resultant bowel obstruction developed in addition to rebound hypersecretion and relief of watery diarrhea. Treatment, consisting of bulk laxatives in appropriate amounts, alleviated the obstipation.