Protective role of cyclooxygenase (COX)-2 in experimental lung injury: evidence of a lipoxin A4-mediated effect.

BACKGROUND: Polymorphoneutrophils (PMNs) are activated by inflammatory mediators following splanchnic ischemia/reperfusion (I/R), potentially injuring organs such as the lung. As a result, some patients develop respiratory failure following abdominal aortic aneurysm repair. Pulmonary cyclooxygenase (COX)-2 protects against acid aspiration and bacterial instillation via lipoxins, a family of potent anti-inflammatory lipid mediators. We explored the role of COX-2 and lipoxin A(4) in experimental I/R-mediated lung injury. MATERIALS AND METHODS: Sprague-Dawley rats were assigned to one of the following five groups: (1) controls; (2) aortic cross-clamping for 45 min and reperfusion for 4 h (I/R group); (3) I/R and SC236, a selective COX-2 inhibitor; (4) I/R and aspirin; and (5) I/R and iloprost, a prostacyclin (PGI(2)) analogue. Lung injury was assessed by wet/dry ratio, myeloperoxidase (MPO) activity, and bronchoalveolar lavage (BAL) neutrophil counts. BAL levels of thromboxane, PGE(2), 6-keto-PGF(1)α (a hydrolysis product of prostacyclin), lipoxin A(4), and 15-epi-lipoxin A(4) were analyzed by enzyme immunoassay (EIA). Immunostaining for COX-2 was performed. RESULTS: I/R significantly increased tissue MPO, the wet/dry lung ratio, and neutrophil counts. These measures were significantly further aggravated by SC236 and improved by iloprost. I/R increased COX-2 immunostaining and both PGE(2) and 6-keto-PGF(1α) levels in BAL. SC236 markedly reduced these prostanoids and lipoxin A(4) compared with I/R alone. Iloprost markedly increased lipoxin A(4) levels. The deleterious effect of SC236 and the beneficial effect of iloprost was associated with a reduction and an increase, respectively, in lipoxin A(4) levels. CONCLUSIONS: Lipoxin A(4) warrants further evaluation as a mediator of COX-2 regulated lung protection.

Transversus abdominis plane block for analgesia in renal transplantation: a randomized controlled trial.

BACKGROUND: The transversus abdominis plane (TAP) block has proven effective in reducing opioid requirements and pain scores for some procedures involving the lower abdominal wall. In this study we assessed its efficacy in patients with end-stage renal failure undergoing cadaveric renal transplantation. METHODS: Sixty-five adult renal transplant recipients were prospectively randomized to receive a standard general anesthetic technique supplemented with levobupivacaine 0.375% 20 mL TAP block or sham block with 20 mL 0.9% saline. Both groups received patient-controlled morphine analgesia and acetaminophen. Patient assessment occurred in the postanesthetic care unit and at 2, 4, 6, 12, and 24 hours. The primary outcome was total morphine consumption in the first 24 hours after renal transplantation. Other outcomes assessed included pain scores, presence of nausea or vomiting, excessive sedation, and respiratory depression. RESULTS: Morphine requirements did not differ between the 2 groups, 31.6 ± 5.6 mg in the TAP group and 32.6 ± 5.5 mg in the control group (95% confidence interval [CI], -8.96 to 7.09, P = 0.817). Pain scores also did not differ significantly at any time point after surgery. Nausea was reported in 53% of the TAP group and 24% of the control group. The relative risk of nausea associated with treatment was 2.2 (95% CI, 1.1 to 4.3, P = 0.017). No patient exhibited excessive sedation or respiratory depression. CONCLUSIONS: The addition of a TAP block to the analgesia regimen for renal transplantation did not reduce morphine requirements.

Anaesthetic considerations for laparoscopic cholecystectomy.

Minimally invasive surgical procedures aim to minimize the trauma of the interventional process but still achieve a satisfactory therapeutic result. Tissue trauma is significantly less than that with conventional open procedures, offering the advantages of reduced post-operative pain, shorter hospital stay, more rapid return to normal activities and significant cost savings. Laparoscopic cholecystectomy is now a routinely performed procedure and has replaced conventional open cholecystectomy as the procedure of choice for symptomatic cholelithiasis. Public expectation and developments in instrumentation have fuelled this change. The physiological effects of intraperitoneal carbon dioxide insufflation combined with variations in patient positioning can have a major impact on cardiorespiratory function, particularly in elderly patients with co-morbidities. Intra-operative complications may include traumatic injuries associated with blind trocar insertion, gas embolism, pneumothorax and surgical emphysema associated with extraperitoneal insufflation. Appropriate monitoring and a high index of suspicion can result in early diagnosis of, and treatment of, complications. Laparoscopic cholecystectomy has proven to be a major advance in the treatment of patients with symptomatic gallbladder disease.

Ambulatory surgery: an overview.

PURPOSE OF REVIEW: Ambulatory surgery is now one of the major areas of surgical and anesthetic practice, with up to 70% of procedures performed in the ambulatory setting. This review focuses on some of the recent studies performed in day case anesthesia. RECENT FINDINGS: Emphasizing the economic benefits of ambulatory surgery, investigators have studied the cost implications of various anesthetic techniques and their impact on patient recovery, discharge times and readmission rates. Quality anesthetic management measures such as mortality, morbidity, postoperative stay and patient satisfaction ensure that perioperative care and treatment are optimized. SUMMARY: Careful patient selection can minimize perioperative events. The concept of multimodal analgesic and antiemetic therapy, in combination with newer anesthetic drugs, help expand the field of ambulatory surgery.

Benzodiazepine premedication may attenuate the stress response in daycase anesthesia: a pilot study.

PURPOSE: Patients undergoing daycase surgery suffer from varying degrees of fear and anxiety. There is conflicting evidence in the literature regarding the benefit of benzodiazepine premedication in daycase surgery. We carried out a prospective, double-blind, randomized pilot study investigating the effect of benzodiazepine premedication on the stress response in patients undergoing daycase anesthesia and surgery. METHODS: Group I (n = 16) received diazepam 0.1 mg*kg(-1) orally 60 min preoperatively; Group II (n = 15) received diazepam 0.1 mg*kg(-1) orally 90 min preoperatively; Group III (n = 30) received a placebo. The stress response was measured by analyzing urinary catecholamine and cortisol levels and by scoring anxiety levels using state-trait anxiety inventory (STAI) scores and visual analogue scores (VAS). RESULTS: Anxiety scores (VAS and STAI scores) were not different between groups. We found a statistically significant reduction in urinary cortisol and noradrenaline levels in the groups receiving diazepam vs placebo. DISCUSSION: The reduction in stress hormones following diazepam premedication, in patients undergoing daycase surgery may support the role for benzodiazepine premedication in this setting. However, further studies are warranted to determine the clinical significance of these findings.

Ocular microtremor during general anesthesia: results of a multicenter trial using automated signal analysis.

Ocular microtremor (OMT) is a fine physiologic tremor of the eye related to neuronal activity in the reticular formation of the brainstem. The frequency of OMT is suppressed by propofol and sevoflurane and predicts the response to command at emergence from anesthesia. Previous studies have relied on post hoc computer analysis of OMT wave forms or on real-time measurements confirmed visually on an oscilloscope. Our overall aim was to evaluate an automated system of OMT signal analysis in a diverse patient population undergoing general anesthesia. In a multicenter trial involving four centers in three countries, we examined the accuracy of OMT to identify the unconscious state and to predict movement in response to airway instrumentation and surgical stimulation. We also tested the effects of neuromuscular blockade and patient position on OMT. We measured OMT continuously by using the closed-eye piezoelectric technique in 214 patients undergoing extracranial surgery with general anesthesia using a variety of anesthetics. OMT decreased at induction in all patients, increased transiently in response to surgical incision or airway instrumentation, and increased at emergence. The frequency of OMT predicted movement in response to laryngeal mask airway insertion and response to command at emergence. Neuromuscular blockade did not affect the frequency of OMT but decreased its amplitude. OMT frequency was unaffected by changes in patient position. We conclude that OMT, measured by an automated signal analysis module, accurately determines the anesthetic state in surgical patients, even during profound neuromuscular blockade and after changes in patient position.