Opioids for Acute Abdominal Pain

Abstract & Commentary

By Donna Woods, DO, Southwest Arizona, Regional Medical Director, Nextcare Urgent Care, Tucson, AZ, is Associate Editor for Urgent Care Alert.

Dr. Woods reports no financial relationships relevant to this field of study.

Synopsis: Opiate administration may alter physical examination findings, but these changes result in no significant increase in management errors.

Source: Ranji SR, et al. Do opiates affect the clinical evaluation of patients with acute abdominal pain? JAMA. 2006; 296:1764-1774.

Traditionally, analgesia has been withheld from patients with acute abdominal pain due to concerns that important physical examination findings may be masked by medicines to treat pain, thus resulting in delayed surgical treatment and increased mortality and morbidity. Several studies have been published in the last 2 decades aiming to discern the effects of analgesia in the management of acute abdominal pain.

This meta-analysis performed a review of 12 Randomly-Controlled Trials (RTCs) published from 1986-2005, which investigated the effects of opioid analgesia on physical examination and management of patients with acute abdominal pain. Nine of the 12 studies were performed on adults (n = 1062) and 3 of the studies were performed on children (n = 291). The studies were all placebo-controlled, and changes were reported in history, physical examination, and management errors (defined as either performing unnecessary surgery or failure to perform necessary surgery in a timely manner.) Pooled-risk ratios with confidence intervals were examined between the groups given opioids and the groups given placebo.

When the analysis was restricted to only those studies demonstrating adequate, subjective analgesia in the patients given opioids (8/12 of the studies), a statistically significant difference in relevant physical examination findings (ie, loss of peritoneal signs) was noted.

However, this difference in physical examination findings was not shown to lead to a statistically significant increase in management errors and, in some studies, opioid administration was actually associated with a small decrease in management errors.

No patients in the studies reviewed by Ranji and colleagues were reported to have experienced complications or death secondary to opioid administration.

Commentary

The studies reviewed by Ranji et al had several limitations. The studies were not adequately powered to show statistically significant differences in management errors between the opioid-treated group and the placebo-treated group.1

There may also be differences in management error rates between opioid and placebo groups when individual, underlying causes of the acute abdomen are examined (ie, appendicitis, cholecystitis, small bowel obstruction, ectopic pregnancy, diverticulitis, etc.)

The use of imaging (ultrasound [U] and computed tomography [CT]) may be performed much more frequently now than when some of the earlier studies used in this meta-analysis were published. The use of U and CT contribute greatly to the accuracy and speed of diagnosis in acute abdominal pain. The standard CT scan is 94% sensitive and 95% specific for the diagnosis of acute appendicitis in adults and adolescents.2

The risks of delaying treatment in the patient with acute abdominal pain are not small. In patients younger than 3-years-old and in patients older than 60, diagnosis of appendicitis is often delayed, leading to perforation rates as high as 80%.3,4 The risk of death from perforation in these studies is approximately 1%.

The most common complication of cholecystitis in older patients, diabetics, and those who delay seeking treatment, is gall bladder gangrene (20%), and 2% of those patients subsequently perforate, which is associated with a high mortality rate.5

Once an acute abdomen is recognized in the urgent care setting, referral decisions must be made promptly to transfer the patient to the Emergency Department (ED) where imaging and surgical evaluation can occur.

These trials examined how treatment with opioids in the ED affects a patient's care when he/she presents with acute abdominal pain. Some urgent care centers have the ability to administer parenteral opioid analgesics on site. Decisions about treatment to be administered in the urgent care setting, prior to transfer to the ED, must be weighed heavily against the risks of altering physical examination and management. In the ED, when an opioid is administered for acute abdominal pain, it is assumed that there is a direct verbal communication between the examining ED doctor (pre-analgesic exam) and the surgeon (post-analgesic exam). When an analgesic is administered in an urgent care center prior to transfer to an ED, not only will the exam be altered for the surgeon, it will be altered for the ED doctor and the ED triage staff (which could result in inappropriate triage and seriously delayed care). Alternatively, the urgent care physician may speak directly to the surgeon and communicate the exam finding prior to the administration of opioids, thereby acting in the same role as the ED physician.

Whether urgent care administration of analgesia would result in management errors remains to be studied. Treatment with other medications in urgent care centers prior to ED transfer, is also controversial. This would include anti-emetics, which would not only relieve the symptom of nausea but could also affect alertness and mental status, which could potentially confuse the clinical picture in the evaluation of both abdominal pain and headaches. Treatment with NSAIDS could remove fever as part of a patient's presentation to an ED doctor or triage nurse. This could have serious consequences in a wide variety of infections. Treatment with an antibiotic prior to referral to an ED can alter the results of blood, urine, sputum, and CSF cultures. All of these treatments prior to referral to the ED have the potential to cause management errors, which can have direct consequences for patients. However, antibiotics should never be delayed while waiting for cultures or other labs to be drawn. The goal is to treat the patient first and then obtain the necessary diagnostic information.

Such pre-hospital treatment decisions should be made on a case-by-case basis and should be made with a clear awareness of the potential to alter important physical exam findings. A verbal report of such treatment should be well-communicated to ED personnel, as well as to the patient and should be documented in the patient's record. A copy of the patient's record should accompany them to the hospital. In urgent care centers, oral medications should not be administered to patients with acute abdominal pain, as they should be considered NPO until surgical evaluation. Injectable NSAIDs (ketorolac) should also be avoided, as they can increase bleeding by inhibiting platelets, should the patient require surgery.

References

  1. Radzik, D, et al. Opiates and acute abdominal pain. JAMA. 2007;297:467-468.
  2. Terasawa T, et al. Systematic review: Computed tomography and ultrasonography to detect acute appendicitis in adults and adolescents. Ann Intern Med. 2004;141:537-546.
  3. Daehlin L. Acute appendicitis during the first three years of life. Acta Chir Scand. 1982;148:291-294.
  4. Horattas MC, et al. A reappraisal of appendicitis in the elderly. Am J Surg. 1990;160:291-293.
  5. Reiss R, et al. Changing trends in surgery for acute cholecystitis. World J Surg. 1990;14:567-570.