1416 PERIOPERATIVE CARE

pain SCOW, side effeds, and post-PCA pain management were analyzed. Although pain scores were not different between groups, Aps patients had fewer side effects, were more likely to receive a loading dose, had their PCA settings adjusted more oRen (P < 0.05), and used more opioid. PS patients were more likely to receive intramuscular medications after PCA discontinuation (P < 0.05). This study demonstrates potentially important PCA management differences between APS and PS physicians. Reprinted with permission from International Anesthesia Research Society.

Editorial Comment: Patient controlled analgesia provides better pain control than on demand injections of narcotics, and has fewer side effects and greater acceptance by patients. This analysis sought to determine whether patient controlled analgesia managed by an acute pain service provided different outcomes than when the surgeon was in charge of the patient controlled analgesia orders. It is noteworthy that the study was conducted by anesthesiologists who had a stake in the outcome.

The conclusion was that there were significant practice differences between an acute pain service managed situation and that which is under the control of the surgeon. However, none of the differences observed really seemed to matter. The most important measure, patient pain scores, was no different. More opioids were used when the acute pain service managed the situation. Although the expertise of specially trained anesthesiologists or an acute pain service team may occasionally be useful, a surgeon familiar with patient controlled analgesia can manage postoperative pain and make appropriate adjustments in the analgesic requirement.

Joseph A. Smith, Jr., M.D.

Low-Molecular-Weight Heparins J. I. WEITZ, Hamilton Civic Hospitals Research Centre and McMaster University, Hamilton, Ontario,

New Engl. J. Med., 337: 687-698, 1997 Canada

No Abstract

Low-Molecular-Weight Heparin in the Treatment of Patients With Venous Thromboembolism THE COLUMBUS INVESTIGATORS New Engl. J. Med., 337: 657-662,1997

Background Low-molecular-weight heparin is known to be safe and effective for the initial treatment of patients with proximal deep-vein thrombosis. However, its application to patients with pulmonary embo- lism or previous episodes of thromboembolism has not been studied.

Methods We randomly assigned 1021 patients with symptomatic venous thromboembolism to fixed-dose, subcutaneous low-molecular-weight heparin (reviparin sodium) or adjusted-dose, intravenous unfraction- ated heparin. Oral anticoagulant therapy with a coumarin derivative was started concomitantly and continued for 12 weeks. Approximately one third of the patients had associated pulmonary embolism. The outcome events studied over the 12 weeks were symptomatic recurrent venous thromboembolism, major bleeding, and death. We sought to determine whether low-molecular-weight heparin is at least equivalent to unfractionated heparin in patients with venous thromboembolism.

Results Twenty-seven of the 510 patients assigned to low-molecular-weight heparin (5.3 percent) had recurrent thromboembolic events, as compared with 25 of the 511 patients assigned to unfractionated heparin (4.9 percent). The difference of 0.4 percentage point indicates that the two therapies have equiv- alent value according to our predetermined definition of equivalence. Sixteen patients assigned to low- molecular-weight heparin (3.1 percent) and 12 patients assigned to unfractionated heparin (2.3 percent) had episodes of major bleeding (P = 0.63), and the mortality rates in the two groups were 7.1 percent and 7.6 percent, respectively (P = 0.89).

Conclusions Fixed-dose, subcutaneous low-molecular-weight heparin is as effective and safe as adjusted- dose, intravenous unfractionated heparin for the initial management of venous thromboembolism, regard- less of whether the patient has pulmonary embolism or a history of venous thromboembolism. Reprinted with permission from Massachusetts Medical Society.

Editorial Comment: Low molecular weight heparin has been investigated as a means of prophylaxis for postoperative thromboembolic events. The efficacy of these drugs is reviewed in this study and the accompanying review. It seems that for prophylaxis of thromboembolic events after abdominal surgery and for treatment of deep venous thrombosis and pulmonary embolism, low molecular weight heparin provides results similar to those seen with unfraction- ated heparin. There are no apparent safety differences between the 2 compounds. Low molec- ular weight heparin is more expensive but it also only requires fixed dose subcutaneous admin- istration as opposed to adjusted dose intravenous administration. Therefore, it is more convenient and the expense of administration is less. New compounds are being developed and tested that may improve results further.

Joseph A. Smith, Jr., M.D.