Peritoneal lavage treatment of experimental pancreatitis

Treatment of Acute Pancreatitis with Peritoneal Dialysis

A patient with acute pancreatitis was treated with peritoneal dialysis and had rapid improvement. At frequent intervals during the dialysis, samples of the patient's blood, urine, and peritoneal fluid were assayed for amylase and lipase. Calculated renal and peritoneal dialysis clearances of these enzymes showed that amylase clearance by the kidney was better than that by peritoneal dialysis; lipase, on the other hand, was more efficiently removed by peritoneal dialysis than by the kidney. A review of the literature on the use of peritoneal dialysis in the treatment of acute pancreatitis is followed by an hypothesis concerning why peritoneal dialysis is so effective in reversing the course of acute pancreatitis.

Clonidine and guanfacine-induced antinociception in visceral pain: possible role of α2/I2 binding sites

Visceral pain is one of the most common forms of pain which is poorly understood. We now studied the influence of imidazoline/guanidinium compounds such as clonidine and guanfacine on visceral pain in the presence or absence of yohimbine and benazoline. To produce visceral pain-related behaviours, formalin (10%) was administered by inserting a fine cannula into the colon via the anus. Each experiment took 1 h. Clonidine (0.001, 0.01 and 0.1 mg/kg, i.p.) and guanfacine (2.5, 5 and 10 mg/kg, i.p.) produced analgesia dose dependently. The clonidine response was inhibited by yohimbine (0.2 mg/kg, i.p.). On the other hand, benazoline (5 mg/kg, i.p.) blocked the antinociceptive effect of guanfacine (5 mg/kg). Benazoline (2.5 and 5 mg/kg) itself also induced analgesia in inflammatory colonic pain. In this study, we used morphine to ensure that the behavioural responses were pain-related. Our results showed that morphine (2.5, 5 and 10 mg/kg, s.c.) produced a dose-dependent antinociception. The morphine (7 mg/kg, s.c.) response was reduced by naloxone (2 mg/kg, i.p.). However, we concluded that both imidazoline (I(2)) and alpha(2)-adrenoceptors may play a role in producing analgesia in visceral pain.

Pancreatic ischaemia in experimental acute pancreatitis: mechanism, significance and therapy

Much clinical and experimental evidence suggests that pancreatic ischaemia in the early phase of acute pancreatitis is important in the development of pancreatic necrosis. While depletion of intravascular volume has often been assumed to be the main circulatory defect, an additional disturbance of pancreatic microcirculation has been demonstrated experimentally. Possible contributory mechanisms include chemical-induced vasoconstriction, direct injury of vessel wall, intravascular coagulation and increased endothelial permeability resulting in pancreatic oedema, haemoconcentration and impaired venous drainage. Pancreatic ischaemia as a consequence of these local effects seems to be responsible for the transition of mild pancreatitis to parenchymal necrosis. In experimental models the beneficial effect of various drugs and of sympathetic blockade has been ascribed to an improvement in pancreatic perfusion. Although effective volume therapy is generally accepted as the mainstay of conservative treatment in acute pancreatitis, the efficacy of different fluid preparations is still controversial, and simple fluid resuscitation has not been shown to prevent the development of parenchymal necrosis. The specific impairment of pancreatic microcirculation cannot be prevented merely by replenishment of intravascular volume with crystalloids, albumin or plasma despite normalization of macrohaemodynamics. In contrast, partial replacement of blood by dextran preparations has been shown to increase pancreatic perfusion by improving blood fluidity. Isovolaemic haemodilution in conjunction with conventional fluid therapy may provide a new and effective means of protecting the pancreas from secondary injury due to the early ischaemic phase of acute pancreatitis.

Camostate (FOY-305) improves the therapeutic effect of peritoneal lavage on taurocholate induced pancreatitis

The effect of peritoneal lavage with the addition of camostate to the lavage fluid on the outcome of taurocholate pancreatitis in rats was studied. Camostate is a low molecular weight protease inhibitor which has been developed recently. Peritoneal lavage was performed for 12 hours and camostate was added to the lavage fluid in five concentrations. At 0.1 mg/ml the survival rate increased significantly (11 of 20 v controls 4 of 20, p less than 0.05); the maximal effect was observed at 0.2 mg/ml, and no effect was seen at 0.01 and 0.05 mg/ml. Adverse effects occurred at 0.5 mg/ml. The addition of 0.1 mg/ml camostate significantly reduced the acidosis in arterial blood: mean (SD) pH 7.30 (0.035) v controls 7.23 (0.054) (n = 9, p less than 0.01) and arterial base excess: -15.4 (1.26) mmol/l v controls: -17.4 (2.51) mmol/l (n = 9, p less than 0.05). There was no difference, however, in plasma amylase activity and in the histological degree of specific tissue damage to the pancreas. A combination of intravenous camostate and lavage with the addition of camostate to the lavage fluid yielded a significantly improved survival compared with treatment with intravenous camostate alone (10 out of 16 animals v intravenous camostate alone, two out of 16, p greater than 0.01). We conclude that lavage with camostate significantly improves the prognosis of severe necrotising pancreatitis in rats.

Long peritoneal lavage decreases pancreatic sepsis in acute pancreatitis

Late infection of devitalized pancreatic and peripancreatic tissue has become the major cause of morbidity in severe acute pancreatitis. Previous experience found that peritoneal lavage for periods of 48 to 96 hours may reduce early systemic complications but did not decrease late pancreatic sepsis. A fortunate observation led to the present study of the influence of a longer period of lavage on late sepsis. Twenty-nine patients receiving primary nonoperative treatment for severe acute pancreatitis (three or more positive prognostic signs) were randomly assigned to short peritoneal lavage (SPL) for 2 days (15 patients) or to long peritoneal lavage (LPL) for 7 days (14 patients). Positive prognostic signs averaged 5 in both groups but the frequency of five or more signs was higher in LPL (71%) than in SPL (47%). Eleven patients in each group had early computed tomographic (CT) scans. Peripancreatic fluid collections were shown more commonly in LPL (82%) than in SPL (54%) patients. Longer lavage dramatically reduced the frequency of both pancreatic sepsis (22% LPL versus 40% SPL) and death from sepsis (0% LPL versus 20% SPL). Among patients with fluid collections on early CT scan, LPL led to a more marked reduction in both pancreatic sepsis (33% LPL versus 83% SPL) and death from sepsis (0% LPL versus 33% SPL). The differences were even more striking among 17 patients with five or more positive prognostic signs. In this group the incidence of pancreatic sepsis was 30% LPL versus 57% SPL and of death from sepsis 0% (LPL) versus 43% (SPL) (p = 0.05). In these patients, overall mortality was also reduced (20% LPL versus 43% SPL). When 20 patients treated by LPL were compared with 91 other patients with three or more positive prognostic signs who were treated without lavage or by lavage for periods of 2 to 4 days, the frequency of death from pancreatic sepsis was reduced from 13% to 5%. In those with five or more signs, the incidence of sepsis was reduced from 40% to 27% (p = 0.03) and of death for sepsis from 30% to 7% (p = 0.08). These findings indicate that lavage of the peritoneal cavity for 7 days may significantly reduce both the frequency and mortality rate of pancreatic sepsis in severe acute pancreatitis.

Visceral pain: a review of experimental studies

This paper reviews clinical and basic science research reports and is directed toward an understanding of visceral pain, with emphasis on studies related to spinal processing. Four main types of visceral stimuli have been employed in experimental studies of visceral nociception: (1) electrical, (2) mechanical, (3) ischemic, and (4) chemical. Studies of visceral pain are discussed in relation to the use and 'adequacy' of these stimuli and the responses produced (e.g., behavioral, pseudoaffective, neuronal, etc.). We propose a definition of an adequate noxious visceral stimulus and speculate on spinal mechanisms of visceral pain.

Continuous peritoneal dialysis in acute experimental pancreatitis in dogs. Effect of aprotinin in the dialysate medium

In 27 beagle dogs, acute necrotizing pancreatitis was induced by retrograde injection of autologous bile and trypsin into the main pancreatic duct. Animals were randomly assigned to the following treatments: group 1--(9 dogs) aprotinin 600,000 KIU/d by i.v. route; group 2--(9 dogs) peritoneal dialysis for 6 d plus 500,000 KIU/L of aprotinin in the dialysate fluid; group 3--(9 dogs) peritoneal dialysis without aprotinin in the dialysate fluid. All dogs of the group 1 died within 16 h following the induction of pancreatitis and extensive necrotizing and hemorrhagic changes were seen in the pancreatic and peripancreatic areas. Six dogs of the group 2 survived and no necrotizing changes were observed 30 or 50 d after the induction of pancreatitis. Three dogs of the group 3 survived, but slight necrotizing lesions were found at the autopsy. The survival rate was higher in dogs with peritoneal lavage (p = 0.0129) or with peritoneal lavage plus aprotinin (p less than 0.0001) than in those receiving i.v. aprotinin, indicating that the latter treatment has no beneficiary effect on the course of acute pancreatitis.

High volume lesser sac lavage in acute necrotizing pancreatitis

The effect of lesser sac drainage with or without lavage on some early predictors and on outcome in acute necrotizing pancreatitis was analysed. The evaluation was made prospectively for 24 patients, in a single centre study. According to Ranson's criteria and laparotomy findings, the lavage and drainage groups were comparable and the pancreatitis was severe and necrotizing in both groups. In a longitudinal analysis of the first 4 postoperative days, lavage did not show any advantage over drainage, as measured by seven prognostic signs (serum creatinine, blood glucose, base excess, haematocrit, white blood cells, C-reactive protein and immunoreactive phospholipase A2 concentration). Furthermore, the study did not find that lavage had any positive effect on the incidence of mortality (36 versus 17 per cent in the drainage group) or on septic complications in acute necrotizing pancreatitis. In the total series the extent of pancreatic necrosis was an essential predictor of the outcome.

Treatment of acute pancreatitis. Comparison of animal and human studies

In this review, we compared the outcome of 25 studies of experimentally induced pancreatitis in animals with 13 studies of human acute pancreatitis in which the same therapeutic agents were used (aprotinin, glucagon, 5-fluorouracil, somatostatin, peritoneal lavage). Whereas 81% of the animal studies had a positive outcome (improvement in survival), only 7.7% of the human studies showed a positive outcome on survival. Most animal studies suffered from a protocol in which treatment was not significantly delayed after induction of acute pancreatitis. Of the 12 human studies that showed no effect of treatment on survival, none had sufficient statistical power (1 - beta error) for the investigators to have confidence in the negative outcomes. This was due to the fact that the studies had too few patients or that the event rates in the untreated populations were too low. Only five of the human studies reported the complication rates of acute pancreatitis in patients who did not die of their disease. Treatment (by any agent) did not improve the complication rate in these studies, but only one of the five reports had sufficient statistical power for the investigators to have confidence in these negative results. Large multicenter studies with sufficient numbers of patients with severe pancreatitis (high mortality and complication rates) are needed to evaluate new therapies in this disease.

Peritoneal lavage combined with volume therapy in porcine hemorrhagic pancreatitis. Effects on hemodynamics, microcirculation, and peritoneal morphology

Acute hemorrhagic pancreatitis was induced in 15 piglets, after which 8 of the piglets were treated with saline infusion only and 7 were treated with saline infusion and peritoneal lavage. Hemodynamic variables were measured hourly. Organ and peritoneal blood flow was determined at 0, 1, and 5 h with radioactive microspheres. Peritoneal morphology was studied at 0, 1, 3, and 5 h with light microscopy and scanning electron microscopy. According to the results, changes in cardiac output, mean blood pressure, and peritoneal blood flow and the peritoneal inflammatory reaction were similar in the two groups. However, a significant increase in heart rate and a significant decrease in the blood flow to the pancreas, liver, and spleen were observed in the saline group, in contrast to the lavage group. In addition, blood flow to the adrenal glands was significantly higher in the saline group after 1 h. In conclusion, peritoneal lavage prevented the increase in heart rate and the development of a significant decrease in pancreatic blood flow in experimental hemorrhagic pancreatitis. The significance of these findings remains to be further evaluated.

Controlled clinical trial of peritoneal lavage for the treatment of severe acute pancreatitis

We performed a multicenter, randomized, controlled clinical trial of therapeutic peritoneal lavage (2 liters per hour for three days) in 91 patients with severe acute pancreatitis. Patients were entered into the study if severe pancreatitis was indicated by multiple laboratory criteria or diagnostic peritoneal lavage. All patients received full supportive treatment. The median time between the onset of symptoms and randomization was 38 hours. Forty-six patients were assigned to the control group and 45 to the lavage group. There were 13 deaths (28 per cent) and 16 patients with major complications (35 per cent) in the control group, as compared with 12 deaths (27 per cent) and 17 patients with major complications (38 per cent) in the lavage group. Lavage did not appear to modify the length of survival, the incidence of pancreatic collections (pseudocysts or abscesses), or the plasma amylase concentration. Considering the statistical power of the design, we conclude that the outcome of severe pancreatitis was not greatly, if at all, influenced by the regimen of peritoneal lavage used in this study.

Continuous peritoneal dialysis as treatment of acute experimental pancreatitis in the rat. I. Effect on length and rate of survival

Continuous peritoneal dialysis significantly prolonged mean length of survival and reduced lethality rate of taurocholate-induced pancreatitis in the rat. The effect was improved by compensating protein loss due to pancreatitis and dialysis treatment. The beneficial effect of intravenous albumin treatment was enhanced when combined with dialysis treatment. Using hypothermic dialysate or adding aprotinin intraperitoneally had no additional effect.

The role of peritoneal lavage in severe acute pancreatitis

Encouraged by reports of the therapeutic efficacy of peritoneal lavage in small series of five or six patients with acute pancreatitis, we have evaluated this treatment in 24 patients with "severe" pancreatitis. One hundred and three patients with "severe" pancreatitis (28% mortality) were separated from 347 with "mild" pancreatitis (0.9% mortality) by previously described early objective signs. Early treatment (Day 0-7) of "severe" pancreatitis included peritoneal lavage through catheters placed nonoperatively in 18 (Group A) and by catheters placed at laparotomy in six (Group C). Early treatment of nonlavaged patients with "severe" pancreatitis was by standard nonoperative measures in 61 (Group B) and included early operation in 18 (Group D). Lavage was continued for 48-96 hours, usually using 36-48 L/24 hours of balanced isotonic dialysate fluid, and was uncomplicated. Lavage led to striking immediate clinical improvement and no lavaged patient (Groups A and C) died during the first 10 days of treatment of pancreatitis. By contrast, 45% of deaths in nonlavaged patients (Group B and D) occurred during this early period, usually from cardiovascular or respiratory failure. Although lavage reduced mortality in subgroups of patients, ultimate overall survival was no affected (Group A, 83%; B, 84%; C, 33%; D,33%). Late peripancreatic abscesses caused most deaths in lavaged patients. These data show that peritoneal complications of severe acute pancreatitis and dramatically reduces early mortality. Lavage does not prevent the late local sequelae of peripancreatic necrosis.