Practice Guidelines for Acute Pain Management in the Perioperative Setting: An

Updated Report

American Society of Anesthesiologists

Bibliography by Section

I. Institutional Policies and Procedures

Education and training of health care providers.

Nonrandomized comparative studies

  1. Coleman SA, Booker-Milburn J: Audit of postoperative pain control: influence of a dedicated acute pain nurse. Anaesthesia 1996, 51:1093-1096
  2. Harmer M, Davies KA: The effect of education, assessment and a standardised prescription on postoperative pain management. The value of clinical audit in the establishment of acute pain services. Anaesthesia 1998, 53:424-430
  3. Rose DK, Cohen MM, Yee DA: Changing the practice of pain management. Anesth Analg 1997, 84:764-772
  4. White CL: Changing pain management practice and impacting on patient outcomes. Clin Nurse Spec 1999, 13:166-172

Observational studies, case reports, or non-pertinent comparison groups

  1. Barnason S, Merboth M, Pozehl B, Teitjen MJ: Utilizing an outcomes appraoch to improve pain mangement by nurses: a pilot study. Clin Nurse Specialist 1998, 12:28-36
  2. Weis OF, Sriwatanakul K, Alloza JL, Weintraub M, Lasagna L: Attitudes of patients, housestaff, and nurses toward postoperative analgesic care. Anesth Analg 1983, 62:70-74
  3. Wilson JF, Brockopp GW, Kryst S, Steger H, Witt WO: Medical students' attitudes toward pain before and after a brief course on pain. Pain 1992, 50:251-256

Documentation of monitoring activities.

Observational studies, case reports, or comparisons without pertinent control groups

  1. Briggs M, Dean KL: A qualitative analysis of the nursing documentation of post-operative pain management. J Clin Nurs 1998, 7:155-163
  2. Camp LD, O'Sullivan PS: Comparison of medical, surgical and oncology patients' descriptions of pain in nurses' documentation of pain assessments. J Adv Nurs 1987, 12:593-598
  3. Clarke EB, French B, Bilodeau ML, Capasso VS, Edwards A, Empoliti J: Pain management knowledge, attitudes and clinical practice: The impact of nurses' characteristics and education. J Pain Symp Manage 1996, 11:18-31
  4. Davis BD, Billings JR, Ryland RK: Evaluation of nursing process documentation. J Adv Nurs 1994, 19:960-968
  5. Ehnfors M, Smedby B: Nursing care as documented in patients' records. Scand J Caring Sci 1993, 7:209-220
  6. Idvall E, Ehrenberg A: Nursing documentation of postoperative pain management. J Clin Nurs 2002, 11:734-742
  7. Salantera S, Lauri S, Salmi TT, Aantaa R: Nursing activities and outcomes of care in the assessment, management, and documentation of children's pain. J Pediatr Nurs 1999, 14:408-415

Acute pain service.

Nonrandomized comparative studies

  1. Bardiau, FM, Taviaux NF, Adelin A, Boogaerts JG, Stadler M: An intervention study to enhance postoperative pain management. Anesth Analg 2003, 96:179-185
  2. Gould TH, Crosby DL, Harmer M, Lloyd SM, Lunn JN, Rees GA, Roberts DE, Webster JA: Policy for controlling pain after surgery: Effect of sequential changes in management. BMJ 1992, 305:1187-1193
  3. Mackintosh C, Bowles S: Evaluation of a nurse-led acute pain service. Can clinical nurse specialists make a difference? J Adv Nurs 1997, 25:30-37
  4. Miaskowski C, Crews J, Ready LB, Paul SM, Ginsberg B: Anesthesia-based pain services improve the quality of postoperative pain management. Pain 1999, 80:23-29
  5. Pesut B, Johnson J: Evaluation of an acute pain service. Can J Nurs Adm 1997, 10:86-107
  6. Sartain JB, Barry JJ: The impact of an acute pain service on postoperative pain management. Anaesth Intensive Care 1999, 27:375-380
  7. Stacey BR, Rudy TE, Nelhaus D: Management of patient-controlled analgesia: a comparison of primary surgeons and a dedicated pain service. Anesth Analg 1997, 85:130-134
  8. Stadler M, Schlander M, Braeckman M, Nguyen T, Boogaerts JG: A cost-utility and cost-effectiveness analysis of an acute pain service. J Clin Anesth 2004; 16:159-167
  9. Tighe SQ, Bie JA, Nelson RA, Skues MA: The acute pain service: effective or expensive care? Anaesthesia 1998, 53:397-403

Observational studies, case reports, or non-pertinent comparison groups

  1. Cross DA, Hunt JB: Feasibility of epidural morphine for postoperative analgesia in a small community hospital. Anesth Analg 1991, 72:765-768
  2. Blanco J, Blanco E, Rodriguez G, Castro A, Alvarez J: One year's experience with an acute pain service in a Spanish University Clinic hospital. Eur J Anaesthesiol 1994, 11:417-421
  3. Cartwright PD, Helfinger RG, Howell JJ, Siepmann KK: Introducing an acute pain service. Anaesthesia 1991, 46:188-191
  4. Macintyre PE, Runciman WB, Webb RK: An acute pain service in an Australian teaching hospital: the first year. Med J Aust 1990, 153:417-422
  5. Ready LB, Oden R, Chadwick HS, Benedetti C, Rooke GA, Caplan R, Wild LW: Development of an anesthesiology-based postoperative pain management service. Anesthesiology 1988, 68:100-106
  6. Schug S, Torrie J: Safety assessment of postoperative pain management by an acute pain service. Pain 1993, 55:387-391
  7. Shah MK: Acute pain service, Kandang Kerbau Hospital, 1995: a first year's experience. Singapore Med J 1997, 38:375-378
  8. Shipton EA, Beeton AG, Minkowitz HS: Introducing a patient-controlled analgesia-based acute pain relief service into southern Africa--the first 10 months. S Afr Med J 1993, 83:501-505
  9. Story DA, Shelton AC, Poustie SJ, Colin-Thome NJ, McIntyre RE, McNicol PL: Effect of an anaesthesia department led critical care outreach and acute pain service on postoperative serious adverse events. Anaesthesia 2006; 61:24-28
  10. Tsui SL, Irwin MG, Wong CM, Fung SK, Hui TW, Ng KF, Chan WS, O'Reagan AM: An audit of the safety of an acute pain service. Anaesthesia 1997, 52:1042-1047
  11. Wheatley RG, Madej TH, Jackson IJB, Hunter D: The first year's experience of an acute pain service. Br J Anaesth 1991, 67:353-359
  12. Zimmerman DL, Stewart J: Postoperative pain management and acute pain service activity in Canada. Can J Anaesth 1993, 40:568-575

II. Preoperative Evaluation of the Patient

Formulating a pain management plan.

Nonrandomized comparative studies

  1. Furdon SA, Eastman M, Benjamin K, Horgan MJ: Outcome measures after standardized pain management strategies in postoperative patients in the neonatal intensive care unit. J Perinat Neonatal Nurs 1998, 12:58-69

III. Preoperative Preparation of the Patient

Education of patients and families.

Randomized controlled trials

  1. Anderson EA: Preoperative preparation for cardiac surgery facilitates recovery, reduces psychological distress, and reduces the incidence of acute postoperative hypertension. J Consult Clin Psychol 1987, 55:513-520
  2. Daltroy LH, Morlino CI, Eaton HM, Poss R, Liang MH: Preoperative education for total hip and knee replacement patients. Arthritis Care Res 1998, 11:469-478
  3. Doering S, Katzlberger F, Rumpold G, Roessler S, Hofstoetter B, Schatz DS, Behensky H, Krismer M, Luz G, Innerhofer P, Benzer H, Saria A, Schuessler G: Videotape preparation of patients before hip replacement surgery reduces stress. Psychosomatic Med 2000, 62:365-373
  4. Egbert LD, Battit GE, Welch CE, Bartlett MK: Reduction of postoperative pain by encouragement and instruction of patients. N Eng J Med 1964, 270:825-827
  5. Elsass P, Eikard B, Junge J, Lykke J, Staun P, Feldt-Rasmussen M: Psychological effect of detailed preanesthetic information. Acta Anaesth Scand 1987, 31:579-583
  6. Fortin R, Kirouac S: A randomized controlled trial of preoperative patient education. Int J Nurs Studies 1976, 13:11-24
  7. Griffin MJ, Brennan L, McShane AJ: Preoperative education and outcome of patient controlled analgesia. Can J Anaesth 1998, 45:943-948
  8. Knoerl DV, Faut-Callahan M, Paice J, Shott S: Preoperative PCA teaching program to manage postoperative pain. Medsurg Nurs 1999, 8:25-33
  9. Lam KK, Chan MT, Chen PP, Kee WD: Structured preoperative patient education for patient-controlled analgesia. J Clin Anesth 2001, 13:465-469
  10. Lilja Y, Ryden S, Fridlund B: Effects of extended preoperative information on perioperative stress: an anaesthetic nurse intervention for patients with breast cancer and total hip replacement. Intensive Crit Care Nurs 1998, 14:276-282
  11. McDonald DD, Freeland M, Thomas G, Moore J: Testing a preoperative pain management intervention for elders. Res Nurs Health 2001, 24:402-409
  12. Shuldham CM, Fleming S, Goodman H: The impact of pre-operative education on recovery following coronary artery bypass surgery. A randomized controlled clinical trial. Eur Heart J 2002, 23:666-674
  13. Watt-Watson J, Stevens B, Costello J, Katz J, Reid G: Impact of preoperative education on pain management outcomes after coronary artery bypass graft surgery: a pilot. Can J Nurs Res 2000, 31:41-56
  14. Wilson JF: Behavioral preparation for surgery: benefit or harm? J Behavioral Med 1981, 4:79-101

Nonrandomized comparative studies

  1. Callaghan P, Cheung YL, Yao KY, Chan SL: The effect of pre-operative information on post-operative anxiety, satisfaction with information, and demand for analgesia in Chinese men having transurethral resection of the prostate (TURP). J Clin Nurs 1998, 7:479-480
  2. Edwinsson M, Arnbjornsson E, Ekman R: Psychological preparation program for children undergoing acute appendectomy. Pediatrics 1992, 82:30-36
  3. Felton G, Huss K, Payne EA, Srsic K: Preoperative nursing intervention with the patient for surgery: outcomes of three alternative approaches. Int J Nurs Studies 1976, 13:83-96
  4. Gammon J, Mulholland C: Effect of preparatory information prior to elective total hip replacement on psychological coping outcomes. J Adv Nurs 1992, 24:303-308
  5. Kempe AR, Gelazis R: Patient anxiety levels: an ambulatory surgery study. AORN 1983, 41:390-396
  6. King I, Tarsitano B: The effect of structured and unstructured pre-operative teaching: a replication. Nurs Res 1982, 31:324-329
  7. Kotzer AM, Coy J, LeClaire AD: The effectiveness of a standardized educational program for children using patient-controlled analgesia. J Soc Pediatr Nurs 1998, 3:117-126
  8. Lin PC, Lin LC, Lin JJ: Comparing the effectiveness of different educational programs for patients with total knee arthroplasty. Orthop Nurs 1997, 16:43-49
  9. Timmons ME, Bower FL: Effect of structured preoperative teaching on patients' use of patient-controlled analgesia (PCA) and their management of pain. Orthoped Nurs 1993, 12:23-31

Observational studies, case reports, or non-pertinent comparison groups

  1. Wilder-Smith CH, Schuler L: Postoperative analgesia: pain by choice? The influence of patient attitudes and patient education. Pain 1992, 50:257-262

IV. PreoperativeTechniques for Pain ManagementPreparation of the Patient

Central Regional Techniques (epidural or intrathecal analgesia) with opioids versus postincisional opioids, placebo, local anesthetics, or IV, IM, or oral opioids).

Preoperative or Preincisional:

Morphine

Randomized controlled trials: preincisional morphine vs postincisional morphine

  1. Kundra P, Gurnani A, Bhattacharya A: Preemptive epidural morphine for postoperative pain relief after lumbar laminectomy. Anesth Analg 1997, 85:135-138
  2. Subramaniam B, Pawar DK, Kashyap L: Pre-emptive analgesia with epidural morphine or morphine and bupivacaine. Anaesth Intensive Care 2000, 28:392-398

Randomized controlled trials: preincisional morphine vs placebo

  1. Abboud TK, Dror A, Mosaad P, Zhu J, Mantilla M, Swart F, Gangolly J, Silao P, Makar A, Moore J, Davis H, Lee J: Mini-dose intrathecal morphine for the relief of post-cesarean section pain: Safety, efficacy, and ventilatory responses to carbon dioxide. Anesth Analg 1988, 67:137-143
  2. Gall O, Aubineau JV, Berniere J, Desjeux L, Murat I: Analgesic effect of low-dose intrathecal morphine after spinal fusion in children. Anesthesiology 2001, 94:447-452
  3. Vanstrum GS, Bjornson KM, Ilko R: Postoperative effects of intrathecal morphine in coronary artery bypass surgery. Anesth Analg 1988, 67:261-267

Randomized controlled trials: preincisional epidural or intrathecal morphine vs other routes of administration (IV, IM, or oral)

  1. Banning AM, Schmidt JF, Chraemmer-Jorgensen B, Risbo A: Comparison of oral controlled release morphine and epidural morphine in the management of postoperative pain. Anesth Analg 1986, 65:385-388
  2. Chambers WA, Sinclair C, Scott D: Extradural morphine for pain after surgery. Br J Anaesth 1981, 53:921-925
  3. Fitzpatrick GJ, Moriarty DC: Intrathecal morphine in the management of pain following cardiac surgery. A comparison with morphine I.v. Br J Anaesth 1988, 60:639-644
  4. Tsui SL, Chan CS, Chan AS, Wong SJ, Lam CS, Jones RD: Postoperative analgesia for oesophageal surgery: A comparison of three analgesic regimens. Anaesth Intens Care 1991, 19:329-337

Nonrandomized comparative studies

  1. Shayevitz JR, Merkel S, O'Kelly SW, Reynolds PI, Gutstein HB: Lumbar epidural morphine infusions for children undergoing cardiac surgery. J Cardiothorac Vasc Anesth 1996, 10:217-224
  2. Yamaguchi H, Watanabe S, Motokawa K, Ishizawa Y: Intrathecal morphine dose-response data for pain relief after cholecystectomy. Anesth Analg 1990, 70:168-171

Observational studies, case reports, or non-pertinent comparison groups

  1. Gjessing J, Tomlin PJ: Postoperative pain control with intrathecal morphine. Anaesthesia 1981, 36:268-276
  2. Taylor A, Healy M, McCarroll M, Moriarty DC: Intrathecal morphine: one year's experience in cardiac surgical patients. J Cardiothorac Vasc Anesth 1996, 10:225-228
  3. Tobias JD, Deshpande JK, Wetzel RC, Solca M: Intrathecal morphine as an adjunct to anesthesia for head and neck surgery. South Med J 1990, 83:649-652

Fentanyl

Randomized controlled trials: preincisional fentanyl vs postincisional fentanyl

  1. Katz J, Kavanagh BP, Sandler AN, Nierenberg H, Boylan JF, Friedlander M, Shaw BF: Preemptive analgesia. Clinical evidence of neuroplasticity contributing to postoperative pain. Anesthesiology 1992, 77:439-446

Randomized controlled trials: preincisional fentanyl vs local anesthetics

  1. Harukuni I, Yamaguchi H, Sato S, Naito H: The comparison of epidural fentanyl, epidural lidocaine, and intravenous fentanyl in patients undergoing gastrectomy. Anesth Analg 1995, 81:1169-1174

Randomized controlled trials: preincisional fentanyl vs vs other routes of administration (IV, IM, or oral)

  1. Harukuni I, Yamaguchi H, Sato S, Naito H: The comparison of epidural fentanyl, epidural lidocaine, and intravenous fentanyl in patients undergoing gastrectomy. Anesth Analg 1995, 81:1169-1174

Sufentanil

Randomized controlled trials: preincisional sufentanil vs preincisional placebo

  1. Broekema AA, Kuizenga K, Hennis PJ: Does epidural sufentanil provide effective analgesia per- and postoperatively for abdominal aortic surgery? Acta Anaesthesiol Scand 1996, 40:20-25

Randomized controlled trials: preincisional sufentanil vs other routes of administration (IV, IM, or oral)

  1. Rosseel PM, van den Broek WG, Boer EC, Prakash O: Epidural sufentanil for intra-and postoperative analgesia in thoracic surgery: a comparative study with intravenous sufentanil. Acta Anaesth Scand 1988, 32:193-198

Other Opioids

Randomized controlled trials

  1. Backlund M, Lindgren L, Kajimoto Y, Rosenberg PH: Comparison of epidural morphine and oxycodone for pain after abdominal surgery. J Clin Anesth 1997, 9:30-35
  2. van den Nieuwenhuyzen MC, Burm AG, Vletter AA, Stienstra R, van Kleef JW: Epidural vs. intravenous infusion of alfentanil in the management of postoperative pain following laparotomies. Acta Anaesthesiol Scand 1996, 40:1112-1118

Nonrandomized comparative studies

  1. Girotra S, Kumar S, Rajendran KM: Postoperative analgesia in children who have genito-urinary surgery. A comparison between caudal buprenorphine and bupivacaine. Anaesthesia 1990, 45:406-408

Observational studies, case reports, or non-pertinent comparison groups

  1. Donadoni R, Rolly G: Epidural sufentanil versus intramuscular buprenorphine for postoperative analgesia. A double-blind comparative trial. Anaesthesia 1987, 42:1171-1175

Postincisional:

Morphine

Randomized controlled trials: postincisional morphine vs postincisional placebo

  1. Cullen ML, Staren ED, El-Ganzouri A, Logas WG, Ivankovich AD, Economou SG: Continuous epidural infusion for analgesia after major abdominal operations: A randomized, prospective, double-blind study. Surg 1985, 98:718-728
  2. Jacobson L, Chabal C, Brody MC: A dose-response study of intrathecal morphine: Efficacy, duration, optimal dose, and side effects. Anesth Analg 1988, 67:1082-1088
  3. Kawana Y, Sato H, Shimada H, Fujita N, Ueda Y, Hayashi A, Araki Y: Epidural ketamine for postoperative pain relief after gynecologic operations: A double-blind study and comparison with epidural morphine. Anesth Analg 1987, 66:735-738
  4. Logas WG, El-Baz N, El-Ganzouri A, Cullen M, Staren E, Faber LP, Ivankovich AD: Continuous thoracic epidural analgesia for postoperative pain relief following thoracotomy: A randomized prospective study. Anesthesiology 1987, 67:787-791
  5. Ross DA, Drasner K, Weinstein PR, Flaherty JF, Barbaro NM: Use of intrathecally administered morphine in the treatment of postoperative pain after lumbar spinal surgery: A prospective, double-blind, placebo- controlled study. Neurosurgery 1991, 28:700-704, 1991
  6. Sarma VJ, Bostrom UV: Intrathecal morphine for the relief of post-hysterectomy pain--a double-blind, dose-response study. Acta Anaesth Scand 1993, 37:223-227
  7. Waikakul W, Chumniprasas K: Direct epidural morphine injection during lumbar discectomy for postoperative analgesia. J Medical Assoc Thailand 1992, 75:428-433
  8. Writer WD, Hurtig JB, Evans D, Needs RE, Hope CE, Forrest JB: Epidural morphine prophylaxis of postoperative pain: Report of a double-blind multicentre study. Can Anaesth Soc J 1985, 32:330-338
  9. Yamaguchi H, Watanabe S, Harukuni I, Hamaya Y: Effective doses of epidural morphine for relief of postcholecystectomy pain. Anesth Analg 1991, 72:80-83

Randomized controlled trials: postincisional morphine vs local anesthetics

  1. Jensen BH: Caudal block for post-operative pain relief in children after genital operations. A comparison between bupivacaine and morphine. Acta Anaesth Scand 1981, 25:373-375

Randomized controlled trials: postincisional epidural or intrathecal morphine vs other routes of administration (IV, IM, or oral)

  1. Bourke DL, Spatz E, Motara R, Ordia JI, Reed J, Hlavacek JM: Epidural opioids during laminectomy surgery for postoperative pain. J Clin Anesth 1992, 4:277-281
  2. Harrison DM, Sinatra R, Morgese L, Chung JH: Epidural narcotic and patient-controlled analgesia for post-cesarean section pain relief. Anesthesiology 1988, 68:454-457
  3. Ho ST, Wang TJ, Tang JS, Liaw WJ, Ho CM: Pain relief after arthroscopic knee surgery: intravenous morphine, epidural morphine, and intra-articular morphine. Clin J Pain 2000, 16:105-109
  4. Klinck JR, Lindop MJ: Epidural morphine in the elderly. A controlled trial after upper abdominal surgery. Anaesthesia 1982, 37:907-912
  5. Logas WG, El-Baz N, El-Ganzouri A, Cullen M, Staren E, Faber LP, Ivankovich AD: Continuous thoracic epidural analgesia for postoperative pain relief following thoracotomy: A randomized prospective study. Anesthesiology 1987, 67:787-791
  6. Malviya S, Pandit UA, Merkel S, Voepel-Lewis T, Zang L, Siewert M, Tait AR, Muraszko K: A comparison of continuous epidural infusion and intermittent intravenous bolus doses of morphine in children undergoing selective dorsal rhizotomy. Reg Anesth Pain Med 1999, 24:438-443
  7. Rawal N, Sjostrand UH, Dahlstrom B, Nydahl PA, Ostelius J: Epidural morphine for postoperative pain relief: A comparative study with intramuscular narcotic and intercostal nerve block. Anesth Analg 1982, 61:93-98
  8. Thind GS, Wells JCD, Wilkes RG: The effects of continuous intravenous naloxone on epidural morphine analgesia. Anaesthesia 1986, 41:582-585
  9. Youngstrom PC, Cowan RI, Sutheimer C, Eastwood DW, Yu JC: Pain relief and plasma concentrations from epidural and intramuscular morphine in post-cesarean patients. Anesthesiology 1982, 57:404-409

Nonrandomized comparative studies

  1. Zenz M, Piepenbrock S, Otten B, Otten G, Neuhaus R: Epidural morphine analgesia: I. Postoperative phase. Anaesthesist 1981, 30:77-82

Observational studies, case reports, or non-pertinent comparison groups

  1. Baxter AD, Laganiere S, Samson B, McGilveray IJ, Hull K: A dose-response study of nalbuphine for post-thoracotomy epidural analgesia. Can J Anaesth 1991, 38:175-182
  2. Blacklock JB, Rea GL, Maxwell RE: Intrathecal morphine during lumbar spine operation for postoperative pain control. Neurosurgery 1986, 18:341-344
  3. Blackman RG, Reynolds J, Shively J: Intrathecal morphine: Dosage and efficacy in younger patients for control of postoperative pain following spinal fusion. Orthopedics 1991, 14:555-557
  4. Bozkurt P, Kaya G, Yeker Y: Single-injection lumbar epidural morphine for postoperative analgesia in children: a report of 175 cases. Reg Anesth 1997, 22:212-217
  5. Krane EJ: Delayed respiratory depression in a child after caudal epidural morphine. Anesth Analg 1988, 67:79-82
  6. Valley RD, Bailey AG: Caudal morphine for postoperative analgesia in infants and children: A report of 138 cases. Anesth Analg 1991, 72:120-124
  7. Welch DB, Hrynaszkiewicz A: Postoperative analgesia using epidural methadone: Administration by the lumbar route for thoracic pain relief. Anaesthesia 1981, 36:1051-1054

Fentanyl

Randomized controlled trials: postincisional fentanyl vs postincisional placebo

  1. Chan JHH, Heilpern GNA, Packham I, Trehan RK, Marsh GDJ, Knibb AA: A prospective randomized double-blind trial of the use of intrathecal fentanyl in patients undergoing lumbar spinal surgery. Spine 2006; 31:2529-2533

Randomized controlled trials: postincisional epidural or intrathecal fentanyl vs other routes of administration (IV, IM, or oral)

  1. Baxter AD, Laganiere S, Samson B, Stewart J, Hull K, Goernert L: A comparison of lumbar epidural and intravenous fentanyl infusions for post-thoracotomy analgesia. Can J Anaesth 1994, 41:184-191
  2. Loper KA, Ready LB, Downey M, Sandler AN, Nessly M, Rapp S, Badner N: Epidural and intravenous fentanyl infusions are clinically equivalent after knee surgery. Anesth Analg 1990, 70:72-75

Other Opioids

Randomized controlled trials

  1. Henderson SK, Matthew EB, Cohen H, Avram MJ: Epidural hydromorphone: A double-blind comparison with intramuscular hydromorphone for postcesarean section analgesia. Anesthesiology 1987, 66:825-830
  2. Miguel R, Barlow I, Morrell M, Scharf J, Sansusi D, Fu E: A prospective, randomized, double-blind comparison of epidural and intravenous sufentanil infusions. Anesthesiology 1994, 81:346-352
  3. Roulson CJ, Bennett J, Shaw M, Carli F: Effect of extradural diamorphine on analgesia after caesarean section under subarachnoid block. Br J Anaesth 1993, 71:810-813

Nonrandomized comparative studies

  1. Girotra S, Kumar S, Rajendran KM: Caudal buprenorphine for postoperative analgesia in children: a comparison with intramuscular buprenorphine. Acta Anaesth Scand 1993, 37:361-364

Observational studies, case reports, or non-pertinent comparison groups

  1. Brodsky JB, Chaplan SR, Brose WG, Mark JB: Continuous epidural hydromorphone for postthoracotomy pain relief. Ann Thoracic Surg 1990, 50:888-893
  2. Palmer CM: Continuous intrathecal sufentanil for postoperative analgesia. Anesth Analg 2001, 92:244-245

Postoperative:

Morphine

Randomized controlled trials: postoperative morphine vs postoperative placebo