Postoperative patient-controlled analgesia: meta-analyses of initial randomized control trials

J Clin Anesth. 1993 May-Jun;5(3):182-93. doi: 10.1016/0952-8180(93)90013-5.


Study objective: To compare outcomes during conventional analgesia (as-needed intramuscular dosing) and patient-controlled analgesia (PCA) in postoperative patients by analyzing data from published comparative trials.

Design: Meta-analyses of 15 randomized control trials.

Patients: Seven hundred eighty-seven adult patients (aged 16 to 65) undergoing various operative procedures.

Interventions: Either PCA or conventional analgesia for postoperative pain control.

Measurements and main results: Data were extracted on analgesic efficacy, analgesic use, patient satisfaction, length of hospital stay, and side effects. Meta-analyses of the data showed the following: (1) greater analgesic efficacy when PCA was used, with a mean additional benefit of 5.6 on a scale of 0 to 100 (SED, 2.2; p = 0.006); (2) a nonsignificant trend toward reduced analgesic use in PCA patients, based on a count of trials finding in one direction or the other (p = 0.092); (3) a 42% difference in the proportion of patients expressing satisfaction over dissatisfaction (SED, 20%; p = 0.02), with PCA being preferred; (4) a nonsignificant trend toward shortening of length of hospital stay with PCA use (mean, 0.15 days, SED, 0.13; p = 0.24); (5) no significant differences in the occurrence of any side effect.

Conclusions: Patient preference strongly favors PCA over conventional analgesia. Patients using PCA also obtain better pain relief than those using conventional analgesia, without an increase in side effects. Favorable effect of PCA upon analgesic usage and length of hospital stay did not in the initial trials attain statistical significance. Nonetheless, the favorable trends in the mean effect sizes for both outcomes argue that further studies of both outcomes should be performed to determine whether the favorable impact of PCA upon either may become statistically significant if larger numbers of patients are enrolled.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Analgesia* / adverse effects
  • Analgesia* / statistics & numerical data
  • Analgesia, Patient-Controlled* / adverse effects
  • Analgesia, Patient-Controlled* / statistics & numerical data
  • Analgesics / administration & dosage
  • Analgesics / adverse effects
  • Humans
  • Injections, Intramuscular
  • Length of Stay
  • Pain Measurement
  • Pain, Postoperative / prevention & control*
  • Patient Satisfaction
  • Postoperative Complications
  • Randomized Controlled Trials as Topic
  • Reproducibility of Results
  • Treatment Outcome


  • Analgesics