Hoping to determine whether administering pain medication adversely affected diagnostic accuracy of the physical examination, a group of Finnish surgeons compared oxycodone administered buccally to an equivalent volume of saline placebo to children presenting with undifferentiated abdominal pain. (Arch Pediatr Adolesc Med 2005;159:320.) Sixty-three children met the inclusion criteria, and entered the protocol. Thirty-one received placebo; 32 received 0.1 mg/kg of oxycodone.
There were no significant differences in these patients in age, weight, gender, or physical examination characteristics. Baseline pain scores were identical for the two groups, averaging about 7 cm on a 10 cm visual analog scale. Within half-an-hour of receiving either oxycodone or placebo, both groups of patients experienced some relief of symptoms.
Patients in the placebo group had a pain score of slightly more than 5 cm while those in the oxycodone group had a pain score of slightly less than 5 cm. Three-and-a-half hours after receiving the study drug, patients in the oxycodone group had a pain score of around 3 cm while those in the placebo group remained at roughly 5 cm.
Pain medication did not negatively affect the exam; it improved it
Oxycodone did not negatively affect the clinical examination; if anything, it improved it. Six patients in the oxycodone group had a different pattern of guarding after receiving the medication. Three patients had guarding on initial examination, which resolved after they received pain medication. Three other patients developed guarding after receiving oxycodone.
Effect on Guarding
In the placebo group, guarding was altered in only one patient. This patient had guarding on initial examination, but not after receiving the study drug. All patients who still had guarding after initial drug administration were presumed to have appendicitis and underwent laparotomy. It should be noted that three children who later proved to have appendicitis (one in the oxycodone group and two in the placebo group) did not have guarding before or after administration of the study drug.
Ultimately, 17 patients in the oxycodone group and 14 patients in the placebo group underwent laparotomy for presumed appendicitis. For all except one child in the placebo group, the decision to operate was made one hour after the patient was triaged. But in two other cases, the surgeons chose first to confirm their clinical impression with CT scans.
These two patients were said to have atypical findings. Twelve of the 17 oxycodone patients and nine of the 14 placebo patients had appendicitis proven by histology. One patient in the oxycodone group had a perforated and abscessed distal ileum that was caused by ingestion of a plastic splinter, and one patient in the placebo group had undiagnosed Crohn's disease. Four patients in each group had negative laparatomies.
Four patients were readmitted for abdominal pain after being discharged. Only one underwent laparatomy. This patient was originally assigned to the placebo group, and did not have appendicitis. All patients were asymptomatic one month after completing the study. Two patients, both in the oxycodone group, had minor adverse events; one had a headache, and the other had urticaria. None of the patients had hypoxia or hypotension or were oversedated.
The findings from this study support those of several previous (mostly adult) studies. All demonstrated that the judicious use of analgesic medications does not adversely affect the diagnostic utility of the physical examination in patients with abdominal pain. We should remember that the proscription against the use of analgesia comes from the era of Sir Zachary Cope, who in 1921 wrote: “If morphine be given, it is possible for a patient to die happy in the belief that he is on the road to recovery, and in some cases the medical attendant may for a time be induced to share the delusive hope.”
In Sir Zachary's time this may well have been prudent teaching, but times have changed. Sir Zachary probably made rounds in a horse and buggy or a Model T. I drove to work in a modern vehicle, wrote this column on a computer, and have in my ED advanced imaging technology and monitoring equipment that Sir Zachary could not even imagine. We have abandoned many other practices from bygone eras of medicine; it is probably time for us to abandon this one as well.