Acute pancreatitis – a common indication for hospitalization in the US – is a feared complication of alcohol use, gallstones, abdominal trauma, steroids, mumps, high fat and calcium level, ERCPs and even scorpion stings. Up to 25% of patients with acute pancreatitis will develop severe acute pancreatitis. It’s a tricky clinical situation to manage due to the difficulty in estimating the severity of the disease; yet distinguishing between the two is critical as mortality rates are 1-2% for mild pancreatitis and up to 17% for severe cases. Prior to this study, physicians relied purely on clinical judgment to triage patients to the floor or the ICU, a method known to underestimate the severity of the disease. Ranson et al provided 11 criteria – 5 assessed at admission and the other 6 at 48 hours – to help predict the most severe cases, with the goal of aggressively treating these patients in the ICU or the OR.
The study suffered from many shortcomings, which complicated data analysis. The data itself was likely skewed due to selection and observer bias, the number of patients enrolled, and the variety of treatment methods employed. For example, 21 patients underwent abdominal exploration within 7 days of admission. Another 10 patients were randomized to early operative or non-operative management. Of those, all but one spent at least 8 days in the ICU. An additional category was non-randomized early management where 17 patients were managed by early operation within 48 hours of diagnosis. Operations varied widely, but the existing standard “recommended early laparotomy with cholecystostomy, gastrostomy, [jejunostomy] and pancreatic drainage in patients with severe acute pancreatitis”. With all these variables, it becomes impossible to assess outcomes based on the various treatment modalities employed – the power in each group and for the whole study is greatly reduced. Nonetheless some of the conclusions regarding blood loss and fluid depletion were accurate. Importantly, the authors noted that a worsening BUN in the face of aggressive fluid replacement was a more sensitive index for survival than the BUN at admission.
At the time, the 11 criteria now known as Ranson’s Criteria were the best available for predicting severity. However, more recent studies have demonstrated that Ranson’s criteria as an aggregate are a relatively poor predictor of disease severity. Today we have at our disposal a number of scoring systems that have been shown to be better prognosticators than Ranson’s Criteria. One, the APACHE II scoring, was developed for critically ill ICU patients. Modern guidelines from the American Gastroenterology Association recommend using the APACHE II scoring system because of its good negative predictive value for severe acute pancreatitis. Still, it continues to be difficult to accurately predict outcomes and severity, although early aggressive management and the use of other diagnostic modalities not available to the authors at the time have improved survival.
The complexity of the interactions of numerous risk factors that ultimately lead to an attack of acute pancreatitis almost precludes having a simple scoring system. It seems that Ranson’s criteria are best used during hospital rounds where medical students and residents can rapidly regurgitate them. It is our hope that they recognize this study for its historic value and instead employ APACHE II to guide early management.
(Unfortunately there isn’t even an abstract of the original article available online. For those at UTSW, I can e-mail you a photocopy of the article since it isn’t available online through the library)