Elevated postoperative renal clearance of amylase without pancreatitis after cardiopulmonary bypass

Two postoperative cardiopulmonary bypass patients who had pancreatitis within a two week period provided the impetus for pursuing this study. Amylase-creatinine clearance ratios (ACCR) were measured in a series of ten thoracic surgery patients: six coronary artery bypass patients with cardiopulmonary bypass (cardiac group), and four exploratory thoracotomy patients (pulmonary group). These ratios were obtained in the preoperative, recovery room, and postoperative periods. Comparisons were made among the following data: clinical history, preand postoperative medications, intraoperative vital signs, drugs, and anesthetics. The preoperative mean ACCR was 3.34 per cent. All cardiac patients had a significantly elevated ACCR in the recovery room with a mean of 17.36 per cent (p < 0.05). The ACCR had returned to preoperative levels by the second postoperative day in five of six cases. There were no elevated ACCR levels in the pulmonary group. All patients were asymptomatic for pancreatitis. The intraoperative course of the cardiac patients involved four common factors, besides cardiopulmonary bypass, which were not present in the pulmonary group. These similarities included transfusion of citrated fresh whole blood activated by calcium chloride, hypotension treated with ephedrine, administration of mannitol, and intraoperative morphine analgesia. The mechanisms of increased amylase secretion by calcium chloride or ephedrine administration and transient sphincter of Oddi constriction by morphine or the alpha-adrenergic response of ephedrine are considered with the theoretical implications toward pancreatitis. The background and significance of the ACCR are also analyzed, especially in association with the osmotic diuresis of mannitol and a subsequent low urine creatinine level.     

Inhibition of serum and urine amylase activity in pancreatitis with hyperlipemia.

In 6 of 7 patients with acute pancreatitis and hyperlipemia, inhibition of serum amylase activity was detected by dilution of the serum before assaying for amylase and by correcting for tthe dilution factor. In 4 patients the inhibition phenomenon disappeared within the first few days of hospitalization as the elevated serum triglycerides fell. However, in 2 others there was no relation between triglyceride level and amylase inhibition. Removal of the excess serum lipids by ultracentrifugation did not eliminate the inhibition of amylase activity. Inhibition of amylase activity also occurred in the urine of these patients. No amylase inhibition was demonstrable in lipemic serum from patients without pancreatitis or in pancreatitis serum to which excess lipids were added. The data suggest the presence of a circulating inhibitor of amylase, distinct from the elevated serum lipids, in the serum and urine of patients with acute pancreatitis associated with hyperlipemia. The diagnosis of acute pancreatitis in the patient with abdominal pain and lactescent serum can be facilitated by correcting the serum amylase activity by dilution.     

Incidence of elevated serum amylase levels and pancreatitis after upper abdominal surgery

A group of 100 consecutive patients undergoing upper abdominal surgery at our hospital was evaluated during the postoperative period for elevation of the serum amylase level. Six patients in the group had significantly elevated serum amylase levels, and only one patient had clinical postoperative pancreatitis.     

The P3 iso-enzyme of serum amylase in the management of patients with acute pancreatitis

The concept of the P3 index and its use in separating acute pancreatitis from other causes of hyperamylasaemia is described. The mean P3 index of 12 healthy volunteers was 94.8 per cent. All 69 patients with acute pancreatitis had a P3 index below 80 per cent with a mean value of 67.9 per cent. The P3 index is abnormal longer than the raised serum amylase, which increases diagnostic accuracy. Causes of hyperamylasaemia other than acute pancreatitis have been studied and most patients have a P3 index above 80 per cent, although certain false positive values have been obtained. No patient with acute pancreatitis has had a P3 index above 80 per cent on admission. Five cases of acute pancreatitis have been studied in whom the P3 index remained abnormal; all had continuing pancreatic disease, usually with pseudocyst formation. The test has proved most valuable in identifying those patients at risk of developing subsequent problems. To date, the test cannot be relied upon to help in deciding upon the severity of an attack of acute pancreatitis.     

Can serum and peritoneal amylase and lipase determinations help in the early prognosis of acute pancreatitis?

Serum and peritoneal amylase and lipase levels were determined at an early stage in 73 patients with acute pancreatitis confirmed by computed tomography (CT scan), surgery, and/or postmortem. Each patient was given an enzymatic score (ES), which reflects the predominance of the serum or peritoneal concentration of the two enzymes, as the case may be. This score can thus be either 0, 1, or 2; ES = 0 if neither enzyme is predominant in the peritoneal fluid, ES = 1 if amylase or lipase alone are predominant therein, and ES = 2 if both enzymes are predominant. This enzymatic score appears to be a good indicator of severity of disease, being as it is directly and significantly related to mortality rate, prognostic score as proposed by Ranson, and incidence of extrapancreatic spreads as demonstrated by CT scan. In 38 patients (including two fatalities) with an enzymatic score of 0 or 1, mortality was 5%, whereas in 35 patients (10 fatalities) with ES = 2, mortality was 29% (p less than 0.01).     

术后3 h血清淀粉酶检测对ERCP术后胰腺炎的预测价值

目的 评估ERCP术后3 h血清淀粉酶值对ERCP术后胰腺炎（post-ERCP pancreatitis,PEP）的预测价值。方法 收集2011年10月1日至2014年12月1日我院328例连续行ERCP的患者术后3 h和24 h血清淀粉酶值,并统计PEP的发生情况。将是否发生PEP作为状态变量,两个时间点的血清淀粉酶作为检验变量,采用SPSS13.0系统作ROC曲线,分析术后3 h和24 h血清淀粉酶对PEP的预测价值。结果 328例患者中诊断PEP共17例（5.18%）。术后3 h血清淀粉酶值≤200 U/L共194例（59.15%）,其中PEP 2例（1.03%）;术后3 h血清淀粉酶值>200 U/L共134例（40.85%）,其中PEP 15例（11.19%）;两者比较有统计学差异（x²=19.731;P<0.001）。术后3 h血清淀粉酶值ROC曲线下面积为0.845,诊断准确度良好,最佳Cut-off值为280 U/L,灵敏度82.4%,特异度74.3%,阳性预测值14.7%,阴性预测值98.7%,准确度74.4%,Youden指数56.4%。术后24 h血清淀粉酶值≤600 U/L共284例（86.59%）,其中PEP 1例（0.35%）;术后24 h血清淀粉酶值>600 U/L共44例（13.41%）,其中PEP 16例（36.36%）;两者比较有统计学差异（x²=93.341;P<0.001）。术后24 h血清淀粉酶值ROC曲线下面积为0.977,诊断价值高,最佳Cut-off值为534.5 U/L,灵敏度100%,特异度89.1%,阳性预测值33.3%,阴性预测值100%,准确度89.6%,Youden指数89.1%。结论 ERCP术后3 h血清淀粉酶值对PEP有较好的早期预测价值,特别是有很好的阴性预测价值;当术后3 h血清淀粉酶值>200 U/L并且有胰管插管时,需高度警惕PEP的发生。     

Evaluation of amylase and lipase in the diagnosis of acute pancreatitis

Background : The diagnosis of acute pancreatitis relies heavily on a raised amylase. Methods : In the present study patients were prospectively categorized, without knowledge of pancreatic enzyme levels, into acute pancreatitis (AP; n = 51), disease controls (n = 35), indeterminate as to pancreatitis (n = 189) or exclusions (non‐pancreatitis diseases where amylase may be elevated; n = 53). Results : Enzyme levels were analysed by receiver operator characteristics (ROC) curves, with specificity > 80%. Day 1 serum lipase gave the greatest diagnostic accuracy (area under ROC curve = 0.128; P = 0.041 vs serum amylase). At the calculated diagnostic threshold of 208 U/L, lipase gave a sensitivity of 67% and a specificity of 97%. Other diagnostic thresholds (day 1) were: serum total amylase, 176 U/L (ROC 0.104, sensitivity 45%, specificity 97%), urinary total amylase, 550 U/L (ROC 0.108, sensitivity 62%, specificity 97%) and serum pancreatic isoamylase, 41 U/L (ROC 0.107, sensitivity 63%, specificity 85%). At delayed diagnosis (3 days) no enzyme was superior to lipase. The combination of lipase and amylase did not increase diagnostic accuracy. Conclusion : Serum lipase is recommended for diagnosis of AP, both early and late in the disease. Although highly specific when elevated, all pancreatic enzymes have low sensitivity for diagnosis.