Acute pancreatitis: Problems in adherence to guidelines
ABSTRACTAlthough evidence-based guidelines on managing acute pancreatitis are available, many physicians are not following them. The authors identify and discuss several problems in adherence to guidelines on testing, imaging, and treatment.
KEY POINTS
- Serum amylase and lipase levels are often needlessly measured every day.
- Often, severity assessments are not performed regularly or acted on.
- Often, not enough fluid is replaced, or fluid status is not adequately monitored.
- In many severe cases, enteral or parenteral feeding is not started soon enough.
- Computed tomography is not done in many patients with severe acute pancreatitis, or it is performed too soon.
- In many cases of suspected infected necrosis, fine-needle aspiration is not done.
- Broad-spectrum antibiotics are often used inappropriately in patients with mild acute pancreatitis and in patients with sterile necrotizing pancreatitis who are clinically stable and have no signs of sepsis.
Clinical scoring systems
Several clinical scoring systems have been studied for assessing severity.
Limitations of the Ranson score are that it can only be completed after 48 hours, all the data points are not always obtained, and it cannot be repeated on a daily basis. Owing to these limitations and its less-than-optimal predictive value, the Ranson score has fallen into disuse.
The APACHE II (Acute Physiology and Chronic Health Evaluation II) score is more versatile. It is based on multiple clinical and laboratory values, and it correlates very well with the risk of death in acute pancreatitis. Death rates are less than 4% when the APACHE II score is less than 8, and 11% to 18% when it is 8 or higher.1 The trajectory of the APACHE II score in the first 48 hours is also an accurate prognostic indicator.
Previous limitations of the APACHE II score were that it was complicated and timeconsuming to calculate and required arterial blood gas measurements. Easy-to-use online calculators are now available (eg, www.globalrph.com/apacheii.htm), and the venous bicarbonate level and the oxygen saturation can be substituted for the arterial pH and oxygen partial pressure.
BISAP, a new five-point scoring system,15 was recently prospectively validated.12 “BISAP” is an acronym for the five markers it is based on, each of which has been shown to predict severe illness in acute pancreatitis:
- Blood urea nitrogen level > 25 mg/dL
- Impaired mental status
- SIRS
- Age > 60 years
- Pleural effusion.
The presence of three or more of these factors correlates with higher risk of death, organ failure, and pancreatic necrosis.12
Compared with APACHE II, BISAP has similar accuracy and is easier to calculate. Also, BISAP was specifically developed for acute pancreatitis, whereas APACHE II is a generic score for all critically ill patients.
The Atlanta criteria16 define severe acute pancreatitis as one or more of the following:
- A Ranson score of 3 or higher during the first 48 hours
- An APACHE II score of 8 or higher at any time
- Failure of one or more organs
- One or more local complications (eg, necrosis, pseudocysts, abscesses).
Recommendation: Assess severity at least daily
A severity assessment should be performed at admission and at least every day thereafter. Clinical guidelines recognize the importance of severity assessment but vary in their specific recommendations.
The ACG advises calculating the APACHE II score within 3 days of admission and measuring the hematocrit at admission, at 12 hours, and at 24 hours. The level of evidence is III, ie, “from published well-designed trials without randomization, single group prepost, cohort, time series, or matched case controlled studies”.1
The American Gastroenterological Association (AGA) provides a more generalized recommendation, that “clinical judgment” should take into account the presence of risk factors (eg, age, obesity), presence or absence of SIRS, routine laboratory values (eg, hematocrit, serum creatinine), and APACHE II score when assessing severity and making decisions.2
In a German survey, only 32% of gastroenterologists used the APACHE II score for assessing risk in acute pancreatitis, in spite of national guidelines emphasizing its importance.7 Also, not all patients with severe acute pancreatitis are transferred to a step-down unit or intensive care unit as recommended. In a British study,4 only 8 (17%) of 46 patients with predicted severe acute pancreatitis were transferred, and 8 of the 38 patients who were not transferred died.
FLUID MUST BE AGGRESSIVELY REPLACED AND MONITORED
Problem: Often, not enough fluid is replaced, or fluid status is not adequately monitored.
Fluid must be aggressively replaced to balance the massive third-space fluid losses that occur in the early inflammatory phase of acute pancreatitis. Intravascular volume depletion can develop rapidly and result in tachycardia, hypotension, and renal failure. It may also impair the blood flow to the pancreas and worsen necrosis.
Animal studies show that aggressive fluid replacement supports the pancreatic microcirculation and prevents necrosis.17 It may also support the intestinal microcirculation and gut barrier, preventing bacterial translocation.
In humans, no controlled trials have been done to test the efficacy of aggressive fluid resuscitation in acute pancreatitis. However, the notion that intravascular fluid loss contributes to poor outcomes is inferred from human studies showing more necrosis and deaths in patients with hemoconcentration. In one study, patients who received inadequate fluid replacement (evidenced by a rise in hematocrit at 24 hours) were more likely to develop necrotizing pancreatitis.18
