Perioperative Nonsteroidal Anti-inflammatory Drugs Research Articles

A Comparison of Multimodal Perioperative Analgesia to Epidural Pain Management After Gastric Bypass Surgery

We compared pain intensity, analgesic consumption, patient satisfaction, and length of stay in 114 patients undergoing gastric bypass surgery under general anesthesia. Patients were randomized to incisional local anesthetic infiltration plus postoperative patient-controlled analgesia (Group A), epidural anesthesia and analgesia (Group B), or postoperative patient-controlled analgesia (Group C). All received perioperative nonsteroidal antiinflammatory drugs. Age, sex, body mass index, length of stay, and patient satisfaction were equivalent in all groups. Pain at time 0 and 36 h was the smallest in Group B, greater in Group A, and greatest in Group C. Pain scores in a subset of Group A were lower at all times than in Groups B and C, but this difference was significant only at 0, 12, and 36 h. In responders, infiltration analgesia as part of a multimodal regimen offers a simple, safe, and inexpensive alternative to epidural pain control.

Non-steroidal anti-inflammatory drugs for preventing heterotopic bone formation after hip arthroplasty.

Heterotopic bone formation (HBF) in the soft tissues surrounding the hip joint is a frequent complication of hip surgery. Non-steroidal anti-inflammatory drugs (NSAIDs) administered in the immediate perioperative period reduce the risk of HBF. However, the magnitude of the effect on HBF, and the effects on other associated outcomes are uncertain. To determine the effects of perioperative NSAID therapy versus control on the risk of HBF and other outcomes in patients undergoing hip arthroplasty. Medline, Current Contents and Cochrane Controlled Trials Register, and reference lists of all relevant reports were searched. Principal investigators and the manufacturers of the study drugs of eligible trials were approached. The most recent search was conducted in July 1998. All trials which enrolled patients scheduled to undergo hip arthroplasty with random or quasi-random allocation to perioperative NSAID or control and that recorded post-operative radiographically determined HBF. The primary outcome was post-operative radiographic HBF. Secondary outcomes were pain, disability, gastro-intestinal and other bleeding complications, and other causes of major morbidity or mortality. Two reviewers independently assessed methodological quality and extracted data. All analyses were conducted on dichotomised outcomes. Twelve randomised and two quasi-randomised trials involving a total of 4,377 patients were included. Overall, in 13 trials that examined the effects of medium to high doses of NSAIDs, there was a reduced risk of developing HBF after hip surgery (62% reduction, 95% confidence interval 56% to 67% reduction). In contrast, one large trial examining low-dose aspirin, demonstrated no effect on the risk of HBF (2% reduction, 95% confidence interval 15% reduction to 12% increase). There was strong evidence of differences in the size of the treatment effects observed between the trials examining medium to high doses of NSAIDs, but reasons were not clearly identified. There was a non-significant one third increased risk of gastro-intestinal side effects among patients assigned NSAIDs (29% increase, 95% confidence interval 5% reduction to 76% increase). Most of this increase was due to an increased risk of minor gastro-intestinal complications. Data on the late post-operative outcomes of pain, impaired physical function and range of joint movement were few and no formal overviews of the effects of NSAIDs on these outcomes were possible. Perioperative NSAIDs appear to produce between a one half and two thirds reduction in the risk of HBF. With routine use, such agents may be able to prevent 15-20 cases of HBF (3-4 severe) among every 100 total hip replacements performed. However, while medium to high doses of perioperative NSAIDs clearly produce a substantial reduction in the incidence of radiographic HBF, there remains some uncertainty about short-term side effects of treatment and substantial uncertainty about effects on long-term clinical outcomes such as chronic pain and impaired physical function. The net effect of routine HBF prophylaxis with NSAIDs requires formal assessment in a randomised trial designed to determine the balance of benefits and risks for all outcomes.

Intraarticular Morphine in the Multimodal Analgesic Management of Postoperative Pain After Ambulatory Anterior Cruciate Ligament Repair

Reconstruction of the anterior cruciate ligament (ACL) is associated with a considerable degree of postoperative pain.Our customary multimodal approach to postoperative analgesia after ambulatory ACL surgery includes perioperative nonsteroidal antiinflammatory drugs, pre- and postincisional intraarticular (IA) bupivacaine (B), and postoperative cryotherapy using an external cooling system. This study was designed to determine whether the addition of IA morphine (MS) provides improved postoperative analgesia. One hundred patients scheduled for elective ambulatory ACL repair received our standard multimodal therapy. After surgery, patients were randomized to one of four study groups. Group 1 received 30 mL of 0.25% B IA. Group 2 received 30 mL of normal saline IA and 5 mg of MSIA. Group 3 received 30 mL of 0.25% bupivacaine IA and 5 mg of MS IV. Group 4 received 30 mL of 0.25% B IA and 5 mg of MS IA. The addition of IA B postoperatively provided prolonged analgesia and decreased postoperative pain and analgesic requirements. The addition of MS to IA B did not provide additional postoperative analgesia. We conclude that patients undergoing ambulatory ACL repair using our standard multimodal analgesic regimen failed to receive additional postoperative analgesia when MS was added to the IA B. Implications: Patients receiving a multimodal analgesic regimen of perioperative nonsteroidal antiinflammatory drugs, intraarticular bupivacaine, and external cooling did not receive any additional analgesia from intraarticular morphine. (Anesth Analg 1998;86:374-8)

Do the pharmacodynamics of the nonsteroidal anti-inflammatory drugs suggest a role in the management of postoperative pain?

Until recently, nonsteroidal anti-inflammatory drugs (NSAIDs) were regarded as weak analgesic agents with a potent antiplatelet effect that severely limited their perioperative usefulness. However, the recent development of injectable NSAIDs has stimulated a re-evaluation of the potential role of this class of drugs in postoperative pain management. In general surgery, NSAIDs have been shown to be effective analgesics when administered after surgery, as judged by either a reduction in pain scores and/or by an opioid sparing effect. Parenteral NSAIDs alone, notably ketorolac and diclofenac, may be adequate or even preferred analgesic agents after minor surgery. In dental surgery, NSAIDs produce greater initial analgesia than steroids, although the latter produce greater suppression of swelling and less functional loss. NSAID pretreatment results in only modest suppression of swelling compared with placebo. These data suggest that the acute analgesic effects of NSAIDs in oral surgery and probably other models result from suppression of a nociceptive process, rather than a generalised anti-inflammatory effect. This view challenges the traditional association between inhibition of prostaglandin synthesis and the therapeutic effects of these drugs. The variety of NSAIDs leads to a range in half-lives from short, e.g. diclofenac (1 h), intermediate, e.g. ketorolac (5h), to long, e.g. tenoxicam (60h), which has implications for both convenience of the dosage regimen and drug accumulation. For some racemic NSAIDs (e.g. ibuprofen), metabolic 'activation' of the inactive R-enantiomer to the active S-enantiomer occurs. Renal dysfunction may increase both the plasma concentration and body residence time of NSAIDs, thereby increasing the risk of adverse effects. The concomitant effects of anaesthesia have not yet been studied. The principal concern regarding the use of perioperative NSAIDs is the risk of decreased haemostasis and wound healing. Although it has been found that NSAIDs prolong bleeding times in patients, values generally remain below the upper limits of those in generally healthy patients. Healing of gastrointestinal anastomoses may be compromised by NSAID administration but corneal healing and bone remodelling are not. There is a need for further research into the potential for renal side effects with NSAIDs in the perioperative setting, where the effects of anaesthesia and surgery may increase the risk of side effects, particularly in elderly patients. The main benefits of NSAIDs derive from opioid sparing (e.g. reduction in perioperative nausea and vomiting and improvement in ventilation), although some studies allude to an enhanced quality of analgesia from the combination compared with either NSAID or opioid alone. The question of pre- vs postinjury treatment with NSAIDs remains unresolved.

Are perioperative nonsteroidal anti-inflammatory drugs ulcerogenic in the short term?

It is well documented that long term treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) increases the risk of peptic ulcer and that gastroduodenal mucosal erosions can be demonstrated in volunteers within 1 week of treatment initiation. However, long term studies in nonsurgical patients have not documented gastroduodenal complications within the first week of treatment. Cumulative data from controlled studies of perioperative (> or = 48 hours and < or = 7 days) treatment with NSAIDs do not suggest an increased risk of gastroduodenal complications (such as bleeding/perforation) within this time frame. We conclude that the otherwise well documented gastrointestinal side effects of prolonged treatment with NSAIDs should not hinder short term NSAID treatment for improved analgesia after surgery.

Cardiovascular risks and benefits of perioperative nonsteroidal anti-inflammatory drug treatment.

Prostaglandins participate in the regulation of blood pressure in normotensive and hypertensive subjects; vascular tone is subject to the continuous relaxing influence of endogenous vasodilating prostaglandins. Prostaglandin I2 (PGI2; prostacyclin), probably the most important physiological modulator of vascular tone, decreases blood pressure together with a concomitant increase in cardiac output and a reduction in systemic vascular resistance secondary to peripheral vasodilation. In addition, vasodilation within the splanchnic, pulmonary and coronary vascular beds has been observed, with increased blood flow through the mesenteric, renal and coronary vascular beds. These changes in regional blood flow have been associated with the inhibition, by PGI2, of the vasoconstrictor response to sympathetic nervous stimulation and pressor hormones [noradrenaline (norepinephrine), angiotensin II]. However, other prostaglandins, such as prostaglandin E2 (PGE2) and prostaglandin F2 alpha (PGF2 alpha), induce coronary vasoconstriction and have different effects on pulmonary artery blood pressure because of their effect on pulmonary vascular resistance. Nonsteroidal anti-inflammatory drugs (NSAIDs; e.g. indomethacin) have been reported to induce hypertension parallel to a fall in cardiac output, suggesting that the underlying mechanism is an increase in systemic vascular resistance. In animal models these agents reduced regional blood flow in the ischaemic myocardium, with a corresponding increase in infarct size. Ibuprofen, which inhibits prostaglandin synthesis to a lesser extent than indomethacin, did not exert systemic or coronary haemodynamic effects. NSAIDs also provide protection in shock models but may exacerbate haemodynamic derangements and decrease survival in acute hypovolaemic hypotension. To what extent do NSAIDs and opioids influence cardiovascular status during the postoperative course and analgesic therapy? Continuous infusion of NSAIDs for analgesia had no major haemodynamic effects. Also, there were insignificant changes in indices of left heart function (cardiac output, stroke volume) and the systemic circulation (mean arterial pressure, systemic vascular resistance) following intravenous ketorolac injections, whereas cardiac output and mean arterial pressure decreased after administration of morphine. The pulmonary circulation was unaffected by ketorolac administration, whereas morphine administration induced an increase in pulmonary vascular resistance. Indices of right and left cardiac work were decreased by morphine. Thus, ketorolac produces fewer haemodynamic effects than morphine, although it is possible that some of the effects of morphine may result from morphine-induced histamine release. NSAIDs may be seen as a worthwhile gain with respect to morphine in clinical situations when hypotension is disadvantageous or when reduction in afterload is not a specific therapeutic aim.