Analgesia should not be given to patients with an acute abdomen because it obscures the diagnosis

Surgical tradition holds that the use of analgesics should be withheld from patients with acute abdominal pain until a diagnosis and management plan have been established by a surgeon. This belief originated early in this century¹ and was emphasized by Cope in his extremely influential book, Early Diagnosis of the Acute Abdomen. Cope claimed that analgesia would mask signs and symptoms, delay diagnosis, and lead to increased morbidity and mortality.² In the most recent edition of Cope's book, Silen condemns the practice of withholding pain medication from a patient with acute abdominal pain. In the next sentence, however, he states that analgesia medication should be given only after a “responsible surgeon” takes a thorough history and performs a thorough physical examination. In actual practice, a surgeon is rarely the first physician to examine a patient with acute abdominal pain, and surgical consultation can take many hours. Given that all the evidence in the medical literature suggests that the use of narcotic analgesia does not obscure diagnosis—and may even improve diagnostic accuracy—in such patients, the traditional practice of withholding pain medication in patients with substantial pain should be seen as inappropriate and inhumane.

Currently five prospective randomized studies in the literature address the use of pain relief in patients with acute abdominal pain.^3,4,5,6,7 Although study methods vary to some degree, all patients were randomly assigned to receive narcotic analgesia or placebo, and all studies used variations of visual analog scales to evaluate pain before and after patients received medication. All the studies then compared the accuracy of the clinician's diagnosis and treatment in patients who did or did not receive narcotics; four of the studies used a double-blind design.

Attard and coworkers performed a randomized double-blind study³ and found that the early administration of opiate analgesics to patients with acute abdominal pain relieved discomfort without compromising diagnosis or treatment. One hundred patients were given either intramuscular papaveretum (a combination of morphine, codeine, and papaverine not available in the US) or placebo, and pain and tenderness scores were substantially reduced in the group receiving an opiate compared with those receiving placebo. There was no difference between the groups in the localization of physical signs, and there was 100% confidence in the surgical registrar's management plan in both groups. The decision whether to perform surgery was ultimately found to be incorrect in only two patients given narcotics compared with nine patients given placebo.

Pace and colleagues, in another double-blind, placebo-controlled study involving 75 patients, found that intravenous morphine sulfate effectively relieved pain and did not alter physicians' ability to evaluate accurately and treat patients appropriately.⁴ Patients received titrated intravenous doses of morphine of as much as 20 mg. Three diagnostic or management errors occurred in each group.

LoVecchio and associates also found that the early intravenous administration of 5 to 10 mg of morphine did not affect the diagnosis or treatment of patients with acute abdominal pain.⁵ The use of morphine was associated with some change in tenderness and localization in half the patients but led to no delays in care or eventual morbidity.

In a study by Vermeulen and colleagues, morphine was used to evaluate the effect of early pain relief on US physicians' performance and surgical decision making.⁶ The use of morphine improved pain compared with that of placebo and was not found to change the appropriateness of the surgeons' decision making.

Zoltie and Cust randomly assigned patients with acute abdominal pain to receive sublingual buprenorphine hydrochloride or placebo.⁷ Buprenorphine use in this study was found to be no better than placebo for relieving pain; however, its use showed a tendency to localize tenderness while in no way obscuring the final diagnosis.

Thus, all five studies addressing the effects of analgesia on diagnosis and treatment in patients with acute abdominal pain failed to produce any evidence that this practice is harmful. All of these studies, which together involved 748 patients, concluded that the appropriate use of analgesia can effectively decrease pain to a greater degree than it does the localization of tenderness, while possibly even facilitating the ability to make an accurate diagnosis.

Even given this information, the concern has been raised that the use of narcotics can interfere with surgeons' ability to obtain informed consent if an operation or other procedure is required. This concern is unfounded for a number of reasons. First of all, informed consent requires (among other things) that the patient be capable of evaluating the information in a rational manner and then making an informed decision. Although it is possible to give so much narcotic medication that it interferes with a patient's cognitive function, this rarely occurs when medication is given in the amounts needed to relieve acute pain. Most patients who have received narcotics before urgent abdominal surgery feel that they were capable of giving informed consent, despite their medications. In a patient in whom analgesia produces excessive sedation, reversal agents can be used, although this step is rarely needed and should be done with great caution because it can exacerbate pain.

Finally, it could be argued that informed consent is impossible in the absence of analgesia, for two reasons. First, severe pain can impair patients' judgment, so that they are incapable of making truly informed decisions. Second, and perhaps most important, withholding analgesia until consent is signed can rightly be viewed as coercion because patients are led to understand that the relief of pain will only be initiated when the consent form has been signed.

The traditional teaching of withholding pain medication in patients with acute abdominal pain stems from a time when medicine was without modern diagnostic techniques and when the intravenous titration of opiates was not routinely practiced. Early and appropriate pain relief for patients with acute abdominal pain is humane, does not adversely affect diagnostic acumen or clinical decision making, and should be considered part of the initial management of every such patient.