Opioid Analgesia During Evaluation of Acute Abdominal Pain

Clinical Question

Does providing early opioid analgesia during evaluation of acute abdominal pain improve patient comfort or outcomes?

Evidence-Based Answer

Providing early opioid analgesia to patients presenting with acute abdominal pain does not affect or delay management decisions, but it lessens pain intensity as rated by the patient.

Practice Pointers

The differential diagnosis of acute abdominal pain includes many causes that may require urgent surgical treatment or hospitalization such as appendicitis, cholecystitis, bowel obstruction, kidney stones, perforated peptic ulcer, pancreatitis, diverticulitis, pelvic abscesses, and ectopic pregnancy. Most acute abdominal pain is visceral pain, which is characterized by generalized aching, pressure, or sharp pain. Visceral pain generally responds best to intraspinal local anesthetic or nonsteroidal anti-inflammatory drugs or opioids administered via any route.1 It is common practice to withhold opioid analgesia in patients with acute abdominal pain. This practice is based on the theory that opioids might mask symptoms, causing inaccurate or delayed diagnostic and treatment decisions.

To evaluate the accuracy of this theory, the authors of this Cochrane review searched for randomized controlled trials comparing opioid analgesia with no analgesia in adults with abdominal pain. Six trials, including 699 total patients, were identified. Most of the trials compared 5 to 15 mg of morphine (Duramorph) with an equivalent amount of saline. There were no significant differences between groups in changes in the physical examination, errors in treatment decisions, inaccurate diagnoses, nausea and vomiting, or length of hospitalization. The two studies that reported patient comfort found significant improvement with opioids. There was not enough information to determine if opioid use causes a delay in the decision to operate, affects costs, or affects morbidity. There was also insufficient evidence to suggest an optimal treatment regimen.

Repeat Cesarean Delivery vs. Planned Induction of Labor

Clinical Question

Should women who have had a previous low–transverse cesarean delivery and who require induction of labor be offered a trial of labor?

Evidence-Based Answer

There are no randomized controlled trials (RCTs) of labor induction in women with a low–transverse uterine scar. Observational studies indicate that there is a small increased risk of uterine rupture and adverse fetal outcomes, especially in women induced with prostaglandins. Although induction in these patients is common practice in other countries, based on these data, the American College of Obstetricians and Gynecologists (ACOG) recommends that patients be discouraged from induction of labor after a single previous low–transverse cesarean delivery.

Practice Pointers

Based on retrospective cohort studies, most women with one previous low–transverse cesarean delivery are candidates for vaginal birth and should be counseled and offered a trial of labor.1,2 In a retrospective, population-based review (including more than 20,000 total women), the overall rate of uterine rupture after a previous low–transverse cesarean delivery was 4.5 per 1,000; the rate was 1.6 per 1,000 with repeat cesarean delivery and no labor, 5.2 per 1,000 with spontaneous labor, 7.7 per 1,000 with nonprostaglandin induction, and 24.5 per 1,000 with prostaglandin induction.3

Another study showed that using oxytocin (Pitocin) to augment labor in women with a previous low–transverse cesearan delivery increases the risk of uterine rupture compared with spontaneous labor (8.7 versus 3.6 per 1,000); using oxytocin alone to induce labor increases the risk to 10.7 per 1,000. In women undergoing a trial of labor, the overall uterine rupture–related perinatal death was 0.11 per 1,000. The rate of perinatal hypoxic brain injury was 0.46 per 1,000 trials of labor compared with zero in women who had a repeat cesarean delivery.4

In Australia, New Zealand, and Canada, it is common practice to offer a trial of labor to women with a previous low–transverse cesarean delivery who require induction. Most physicians prefer oxytocin induction rather than cervical ripening with prostaglandins.

The authors of this Cochrane review found no RCTs to help further determine the safety of labor induction after previous cesarean delivery. In particular, it is not clear if prostaglandin use causes adverse outcomes in women attempting vaginal birth or if having an unfavorable cervix is simply a marker for complications.

The ACOG recommends that women who have had one previous low–transverse cesarean delivery be counseled and offered a trial of labor. However, because of limited and inconsistent evidence showing an increased risk of uterine rupture, the ACOG recommends that women who require cervical ripening or induction be discouraged from attempting a vaginal delivery. If a woman attempts a vaginal delivery after a previous low–transverse cesarean delivery, the ACOG recommends that her labor be managed in a hospital with immediate access to emergency obstetric care.

Because data are limited, the individual patient and her physician should make the ultimate decision. Vaginal birth after cesarean delivery should not be attempted in a woman with a classic uterine incision or history of transfundal surgery.2