Peritoneal pH during laparoscopy is dependent on ambient gas environment: helium and nitrous oxide do not cause peritoneal acidosis.

BACKGROUND: Little is know about the effects of different insufflation gases on peritoneal pH during laparoscopy. However, these changes may influence the intracellular signalling system, resulting in altered cell growth or adhesiveness. The aim of this study was to determine the effects of carbon dioxide (CO(2)), nitrous oxide (N(2)O), and helium (He) on parietal and visceral peritoneal pH. The effect of different intraabdominal pressures on parietal and visceral peritoneal pH was also examined. METHODS: We conducted both an ambient gas study and a pressure study. For the ambient gas study, 20 pigs were divided into the following four groups: (a) CO(2), (b) He, (c) N(2)O, and (d) abdominal wall lift (Lift) laparoscopy. Parietal and visceral peritoneal pH were measured at 15 min intervals for 180 min. For the pressure study, 15 pigs were divided into the following three groups: (a) CO(2), (b) He, (c) N(2)O laparoscopy. Baseline values were established for parietal and visceral peritoneal pH. Intraabdominal pressure was then increased stepwise at 1-mmHg intervals to 15 mmHg. After pressure was maintained for 15 min at each setting, parietal and visceral peritoneal pH were measured. RESULTS: Ambient gas environment was the major determinant of parietal peritoneal pH. Carbon dioxide caused parietal peritoneal acidosis. Helium, N(2)O, and Lift caused alkalotic parietal peritoneal pH. Intraabdominal pressure had a minor effect on parietal peritoneal pH. At higher intraabdominal pressure (12-15 vs 5-8 mmHg), CO(2) caused a slight decrease in parietal peritoneal pH, whereas N(2)O and He caused a slight increase in parietal peritoneal pH. Visceral peritoneal pH remained relatively unaffected during all studies. CONCLUSIONS: Parietal peritoneal pH during laparoscopy was highly dependent on the ambient gas environment. The effect of intraabdominal pressure on parietal peritoneal pH was of minor significance. Carbon dioxide caused a slight worsening of parietal peritoneal acidosis at higher intraabdominal pressure, whereas, N(2)O, He, and Lift did not cause parietal peritoneal acidosis.

Congenital duodenal diverticula: a report of three cases and a review of the literature.

Most duodenal diverticula are acquired, extraluminal, and false, but the congenital variety is rare, whether it is intraluminal or extraluminal. We present two cases of extraluminal congenital duodenal diverticula and one of the intraluminal type, and we also review the literature. The clinical presentation involves rather nonspecific abdominal symptoms, and most of these diverticula are incidental findings on upper gastrointestinal series. Duodenoscopy offers the best chance to diagnose the intraluminal diverticula. The complications and methods of treatment of each type of congenital duodenal diverticulum are discussed.

Laser lithotripsy for the management of retained stones.

The morbidity of reoperation for retained biliary stones is not significant. Many techniques have been developed to avoid reoperation. This study analyzes T-tube tract choledochoscopy and lithotripsy using a 504-nm pulsed dye laser for treatment of retained stones. A flexible choledochoscope is passed into the biliary tract and laser energy is delivered under endoscopic visualization after passing a 320-microns laser fiber through the instrument channel. Eight patients were treated in nine sessions. The mean number of pulses was 1512.33, delivered at 3 to 5 Hz with an energy of 100 to 120 mJ. In all patients, the biliary tract was cleared. A single patient's treatment was complicated by transient bacteremia. Mean follow-up was 10 months. Choledochoscopic laser lithotripsy is a safe, effective technique that may also play a major role in laparoscopic common duct surgery.

Changes in intracranial pressure associated with apneumic retractors.

OBJECTIVE: To investigate the effect of apneumic retraction on intracranial pressure (ICP) using a live porcine model. DESIGN: Five 25- to 30-kg pigs had a fiber-optic ICP bolt inserted under general endotracheal anesthesia and were monitored for ICP, mean arterial pressure, arterial blood gas measurements, and intra-abdominal pressure before, during, and after pneumoperitoneum, with each period 30 minutes long. These series of measurements were repeated after artificially raising ICP with an epidural balloon to create a head-injured model. The mean (+/- SE) ICP in the noninjured model at baseline was 13.46 +/- 1.01 mm Hg; during pneumoperitoneum, 18.72 +/- 1.50 mm Hg (P = .0001). Similarly, in the head-injured model, ICP was raised artificially to a new baseline of 22 +/- 1.75 mm Hg with an epidural balloon, and pneumoperitoneum increased ICP to 27.40 +/- 0.93 mm Hg (P = .0001). Pneumoperitoneum was then released, and an apneumic retractor was inserted while maintaining the inflated epidural balloon. MAIN OUTCOME MEASURE: Changes in ICP. RESULTS: Applying anterior wall retraction equivalent to 20 mm Hg was not associated with changes in ICP. These observations were independent of any changes in arterial PCO2 or arterial pH. Following the release of pneumoperitoneum, abdominal wall retraction, and epidural balloon, all measurements reverted to baseline. CONCLUSION: Pneumoperitoneum adversely affects ICP, while apneumic retraction may not affect animals with raised ICP. These findings suggest that pneumoperitoneum should be used with caution in patients with raised ICP, and apneumic retraction may be a safer alternative for laparoscopic evaluation in this population.

The impact of pneumoperitoneum, pneumoretroperitoneum, and gasless laparoscopy on the systemic and renal hemodynamics.

BACKGROUND: The use of therapeutic laparoscopy has become widespread recently. It is important to assess the effects of gaseous and gasless laparoscopy on systemic and renal hemodynamics. STUDY DESIGN: A prospective controlled animal study was performed on 40 well-hydrated pigs. Systemic and renal hemodynamics were monitored during peritoneal insufflation, retroperitoneal insufflation, and abdominal wall lifting for a period of two hours. A laser Doppler flow meter was applied laparoscopically to measure the renal cortical tissue perfusion. RESULTS: Peritoneal insufflation of carbon dioxide to a pressure of 15 mm Hg elicited transient elevations of the aortic pressure and carotid arterial blood flow. Unilateral pneumoretroperitoneum caused a smaller change on systemic hemodynamics. Pneumoperitoneum and pneumoretroperitoneum caused oliguria. Superficial renal cortical blood flow reduction decreased by an average of 60 percent in the compressed kidney, and blood flow returned to the pre-insufflation level after the pressure was released. A gradual decrease of tissue perfusion in the contralateral kidney and a concomitant gradual increase of the intra-abdominal pressure were observed when pneumo-retroperitoneum was maintained for two hours. No significant changes in urinary output and in systemic and renal hemodynamics were found when the abdominal wall was lifted up with a force equivalent to 15 mm Hg. CONCLUSIONS: Significant systemic and renal hemodynamic changes were elicited in gaseous but not in gasless laparoscopy, which may explain the decreased urinary output observed during gaseous laparoscopy. Pneumoperitoneum caused greater systemic and renal hemodynamic alterations than pneumoretroperitoneum; however, the effects were transient and reversible after a period of two hours.

Choledochoscopic removal of retained stones via a T-tube tract.

Common duct stones retained after choledocholithotomy were removed in 11 patients under intravenous sedation using the Olympus fiberoptic choledochoscope passed through a T-tube tract. A total of 39 stones were removed during 12 procedures, with one patient requiring 2 procedures for complete stone removal. All common duct stones were removed, with no patient requiring further operation or procedures for stone removal. The complication rate was low; one patient had pancreatitis and four patients had a transient fever 8 to 12 hours after the procedure. Direct visualization proved an advantage in stone removal, and the patients were not exposed to the radiation required by the fluoroscopic method of stone extraction.

Postoperative T-tube tract choledochoscopy.

One hundred twenty-six patients underwent postoperative fiberoptic T-tube tract choledochoscopy for the management of retained biliary calculi as demonstrated by T-tube cholangiography. Extraction was successful in 94% of patients with retained stones. Thirty-nine patients had more than 1 stone, 20 patients had heptic duct stones, and 14 patients had large stones requiring electrohydraulic lithotripsy or laser fragmentation. Stone removal was not possible in six patients, secondary to either slippage of the T-tube with obliteration of the tract, inability to remove the stones with available instruments, a tortuous tract, or choledochoscope malfunction. Minor complications, most commonly transient fever, occurred in 12 patients. No serious complications or deaths occurred. The advantages of T-tube tract choledochoscopy include direct visualization of the biliary tree, avoidance of radiation exposure, and easy access to hepatic duct stones. This is the preferred method for treating retained biliary calculi in patients with a T-tube in situ.

Encephalopathy, oxygen consumption, visceral amino acid clearance, and mortality in cirrhotic surgical patients.

To assess the relationship of the high mortality of coma in cirrhotic surgical patients to defects in energy metabolism, reduced utilization of amino acids by the liver and other visceral tissues, oxygen consumption, central plasma clearance rate of amino acids (CPCR of amino acids), and the plasma concentrations of plasma inducing factors were measured in a series of 59 cirrhotic patients. They were classed as alert, encephalopathic, and comatose (Groups A, E, and C, respectively). The comatose group was set apart from the other two by a significantly higher mortality of 83 percent (p less than 0.005) combined with a lower whole body oxygen consumption of 103 +/- 6.8 ml/min per m2 compared with 135 +/- 10 ml/min per m2 in alert patients and 159 +/- 12 ml/min per m2 in the encephalopathic patients (p less than 0.01) and CPCR of amino acids of only 120 +/- 20 ml of plasma/min per m2 compared with 240 +/- 30 ml of plasma/min per m2 in the alert patients and 300 +/- 50 in the encephalopathic patients (p less than 0.01). An inverse correlation of tyrosine and phenylalanine concentrations existed with both whole body oxygen consumption (r = -0.56, p less than 0.01) and also with total amino acid clearance (r = -0.61, p less than 0.01). Tyrosine and phenylalanine concentrations also correlated directly with the octopamine concentration (r = 0.64, p less than 0.01). Thus, we conclude that coma is a symptom of hyperaminoacidemia, but that death is the result of impaired oxidative energy production and a deficiency of amino acid clearance for synthesis of proteins required for survival.

Gunshot wounds of the left upper abdominal quadrant associated with multiple intraabdominal injuries.

This study reviews low velocity gunshot wounds of the left upper quadrant of the abdomen and presents four cases recently treated at Boston City Hospital. All patients sustained multiple intraabdominal organ injuries and underwent prompt exploration. Hypotension on admission seemed to be the most reliable sign for a prolonged and complicated hospital course. The essential preoperative studies in stable patients should include a chest x-ray and intravenous pyelogram. Intraoperatively, injury to the body or tail or the pancreas is best managed by distal pancreatectomy and sump drainage. Exploration of the retroperitoneum is warranted for bleeding from the kidney. Initial maneuvers should be designed to control hemorrhage from the renal pedicle. If this is unsuccessful or the renal parenchyma is badly fragmented, nephrectomy should be performed. The complications noted in our patients, infection (pneumonia and left subphrenic abscess) and hemorrhage, are comparable to those reported in most large series. Pancreatic complications (fistulas, pseudocysts, and pancreatitis) were not noted.

Lower gastrointestinal bleeding. Diagnostic approach and management conclusions.

The management of patients with lower gastrointestinal bleeding requires a systematic approach based on defined diagnostic and therapeutic methods. Although in 80 percent of patients bleeding will stop spontaneously, 25 percent will have rebleeding and 50 percent of those with rebleeding will bleed again. Angiography documents specific bleeding sites but raises questions related to the incidence, site and frequency of bleeding, as well as the necessity of demonstrating extravasation. We reviewed 49 arteriograms performed for lower gastrointestinal bleeding. We conclude from our findings that angiography identifies a presumptive cause of bleeding in 49 percent of patients; angiography identified the site of bleeding in 86 percent of the patients with active bleeding, thus allowing segmental colectomy. We believe that documentation of angiodysplasia in a patient with lower gastrointestinal bleeding is presumptive evidence for the site of bleeding. Angiography is useful and worthwhile in the work-up of patients with lower gastrointestinal bleeding in an attempt to plan localized, definitive resection, and this may lead to a lower mortality rate.

Gastrointestinal tract bleeding. Common dilemmas in management.

An accurate diagnosis is the prerequisite in defining gastrointestinal tract bleeding at any level. Flexible endoscopy is the mainstay of diagnosis, and, particularly in the colon, it may be used as a therapeutic tool in conjunction with fulguration. Radionuclide scanning and arteriography have a place in diagnosis when endoscopy fails. The management of variceal bleeding is, in the main, injection sclerotherapy, operation being reserved for patients who rebleed after injection sclerotherapy or in whom a long-term course of sclerotherapy fails. The management of patients with colonic bleeding depends on the accurate pinpointing of bleeding before operation followed by limited excision of the located bleeding site. Some sources of lower gastrointestinal-tract bleeding can be treated by therapeutic endoscopy.

Biliary laser lithotripsy.

Laser lithotripsy is an excellent method of fragmenting those biliary stones that cannot be removed easily by less technically advanced methods such as basket extraction. The energy can be delivered through fine flexible fibers, around 200 to 320 microns in diameter, that can be passed through the channels of a variety of small endoscopes. Currently, the optimal laser seems to a pulsed system because of the conversion of light to acoustic energy with minimal heating of the surrounding tissues, thus avoiding the chance of tissue injury and perforation. The best wavelength seems to be 504 nm, because at this wavelength, there is maximum absorption of laser energy by pigment stones, resulting in fragmentation using low-energy pulses. With further research, optimal wavelengths and pulse durations may emerge.

Pathogenesis of cholesterol gallstones.

The factors leading to cholesterol cholelithiasis are probably multiple. Although the secretion of bile supersaturated with cholesterol seems to be a common feature among all patients who form cholesterol stones, a variety of pathophysiologic events can produce an increase in lithogenicity. Dietary factors, particularly in the grossly obese, lead to an absolute increase in secretion of cholesterol into bile. Occasionally, excessive loss of the bile salt pool, for example with regional ileitis, may decrease the ability of bile salts to solubilize cholesterol. In many other, subtle alterations in the enterohepatic circulation of bile salts may adversely affect solubility by both decreasing the secretion of bile salts and increasing the secretion of cholesterol. Regardless of its cause, supersaturation of bile with cholesterol appears to be a prerequisite for gallstone formation. However, additional factors within the gallbladder, such as increased secretion of glycoprotein, increased absorption of fluids, infection, and stasis, appear to contribute to the formation of macroscopic stones.

Carbon dioxide pneumoperitoneum causes severe peritoneal acidosis, unaltered by heating, humidification, or bicarbonate in a porcine model.

BACKGROUND: Carbon dioxide (CO(2)) is the most common gas used for insufflation in laparoscopy, but its effects on peritoneal physiology are poorly understood. This study looks at the changes in peritoneal and bowel serosal pH during CO(2) pneumoperitoneum, and whether heating and humidification with or without bicarbonate alters the outcomes. METHODS: Twenty-one pigs divided into four groups as follows: (1) standard (STD) laparoscopy (n = 5); (2) heated and humidified (HH) laparoscopy (n = 6); (3) heated and humidified with bicarbonate (HHBI) laparoscopy (n = 5); and (4) laparotomy (n = 5). Peritoneal pH, bowel serosal pH, and arterial blood gas (ABG) were obtained at 15-min intervals for 3 h. RESULTS: Severe peritoneal acidosis (pH range 6.59-6.74) was observed in all laparoscopy groups, and this was unaltered by heating and humidification or the addition of bicarbonate. Bowel serosal acidosis was observed in all laparoscopy groups with onset of pneumoperitoneum, but it recovered after 45 minutes. No significant changes in peritoneal or bowel serosal pH were observed in the laparotomy group. CONCLUSION: CO(2) pneumoperitoneum resulted in severe peritoneal acidosis that was unaltered by heating and humidification with or without bicarbonate. Alteration in peritoneal pH may conceivably be responsible for providing an environment favorable for tumor-cell implantation during laparoscopy.

Gastric outlet obstruction secondary to pancreatic cancer: surgical vs endoscopic palliation.

BACKGROUND: Gastric outlet obstruction in patients with pancreatic cancer has a grim prognosis. Open surgical bypass is associated with high morbidity, whereas endoscopic duodenal stenting appears to provide better palliation. METHODS: We reviewed the medical records of patients with gastric outlet obstruction secondary to pancreatic carcinoma who were admitted to our clinic between 1 October 1988, and 30 September 1998. The data included stage of disease, American Society of Anesthesiologists (ASA) class, surgical interventions, complications, and survival. RESULTS: A total of 250 patients with pancreatic cancer were identified. Twenty-five of them (10%) had gastric outlet obstruction. Of these 25, 17 were treated with gastrojejunostomy, six had duodenal stenting (Wallstent), and two were resectable. There was no significant difference between the gastrojejunostomy group and the duodenal stenting group in ASA class or stage of disease. For the gastrojejunostomy group, median survival was 64 days (range, 15-167) and postoperative stay in hospital was 15 days (range, 8-39). For the duodenal stenting group, median survival was 110.5 days (range, 42-212) and postoperative stay was 4 days (range, 2-6). Ten patients (58.8%) in the gastrojejunostomy group had delayed gastric emptying. All of the patients in the duodenal stenting group were able to tolerate a soft diet the day after stent placement. Thirty-day mortality in the gastrojejunostomy group was 17.64%; in the duodenal stenting group, it was 0. CONCLUSION: In pancreatic carcinoma patients with gastric outlet obstruction, duodenal stenting results in an earlier discharge from hospital and possibly improved survival.

Electrohydraulic lithotripsy (EHL) for the treatment of large retained common duct stones.

Retained biliary stones may be too large for extraction through the existing T-tube tract. It may be necessary to dilate the tract, crush the stones or use endoscopic papillotomy. There are reports of stones and the extracting basket becoming stuck in the T-tube tract and tract ruptures caused by extracting large stones. In this study electrohydraulic lithotripsy (EHL) is used in combination with T-tube tract choledochoscopy for the fragmentation of large stones prior to basket extraction. T-tube choledochoscopy was performed under IV sedation and sterile conditions no sooner than one month following common bile duct exploration. The Olympus 4.9-mm choledochoscope was passed through the T-tube tract to visualize the stone. A #5 Fr EHL probe was passed through the endoscope and advanced to within 1 mm of the surface of the stone. EHL discharge was started at a low energy level being increased until the spark discharges caused stone fragmentation. The resultant stone fragments were basket extracted under direct vision. The procedure was used in twelve patients with removal of all stones in eleven patients. Eight patients were treated with one endoscopic session. Because of multiple stones, two patients required two sessions and one patient four sessions. In one patient stone position prevented adequate fragmentation and endoscopic papillotomy also failed. Repeat choledochoscopy and EHL were successful. There were no complications of EHL or choledochoscopy in any of the patients. EHL was both effective and safe for fragmentation of large common duct stones when performed under direct vision using a choledochoscope.