Anesthesia and analgesia
-
Anesthesia and analgesia · Mar 1999
Randomized Controlled Trial Multicenter Study Clinical TrialA double-blinded evaluation of propacetamol versus ketorolac in combination with patient-controlled analgesia morphine: analgesic efficacy and tolerability after gynecologic surgery.
We assessed the relative morphine consumption in a combined analgesic regimen (on-demand morphine plus the nonopioids propacetamol or ketorolac) after gynecologic surgery. Two hundred women randomly received two i.v. doses of propacetamol 2 g or ketorolac 30 mg in a double-blinded, double-dummy trial. Patients were monitored for 12 h, and the following efficacy variables were assessed: total dose of morphine, pain intensity, and global efficacy. Safety and tolerability were evaluated by the occurrence of adverse events, especially the presence and intensity of gastrointestinal symptoms. Hemostatic variables were measured 30 and 60 min after the first infusion; arterial blood pressure, heart and respiratory rates, sedation scores, and renal and hepatic function were also assessed. Total morphine requirements were not significantly different between the propacetamol (10.6 +/- 4.8 mg) and ketorolac (10.2 +/- 4.4 mg) groups. The evolution of pain intensity and the global efficacy also showed similar patterns in the two groups: 70.2% of patients in the propacetamol group rated the efficacy as "good/ excellent" compared with 68.2% in the ketorolac group. There were no clinically significant changes in vital signs or laboratory values and no observed differences between the two groups, although ketorolac slightly, but not significantly, prolonged the bleeding time. Epigastric pain was present in 9% and 15% of patients receiving propacetamol and ketorolac, respectively. There were two adverse events in the propacetamol group and four in the ketorolac group. Propacetamol demonstrates an efficacy similar to that of ketorolac and has an excellent tolerability after gynecologic surgery. ⋯ Propacetamol and ketorolac, combined with patient-controlled analgesia morphine, show similar analgesic efficacy after gynecologic surgery. Morphine consumption and pain scores were comparable in the two studied groups. Propacetamol is as effective as ketorolac and has an excellent tolerability after gynecologic surgery.
-
Anesthesia and analgesia · Mar 1999
Randomized Controlled Trial Clinical TrialAdenosine reduces secondary hyperalgesia in two human models of cutaneous inflammatory pain.
Secondary hyperalgesia is characterized by increased sensitivity to noxious mechanical stimuli in the area surrounding injured skin. The pathophysiological mechanisms involve increased excitability of second-order neurons located in the spinal cord, i.e., central sensitization. The mechanisms behind this phenomenon may be of importance in clinical pain, including neuropathic pain. To study the effects of systemic infusion of the endogenous compound adenosine (ADO) on sensory function, a superficial cutaneous burn injury was induced by the 4-min topical application of mustard oil or by heat (47 degrees C for 7 min) during i.v. ADO infusion (60 microg x kg(-1) x min(-1)). Healthy human subjects (n = 10 for each model) were tested, using a blinded, placebo-controlled procedure. The area of secondary hyperalgesia, as well as tactile and thermal sensory function, was tested using psychophysical methods during and after treatments. ADO significantly reduced the area of secondary hyperalgesia in both models. The maximal reduction compared with placebo was 58% +/- 20% (heat burn) and 39% +/- 13% (mustard oil burn). No other differences in sensory function were observed. The results are interpreted as an ADO-induced modulatory effect on the mechanisms of central sensitization. ⋯ We tested the effects of adenosine on the development of increased sensitivity in the skin surrounding a superficial skin injury in humans. A superficial skin bum was induced with a chemical irritant or heat. The results show that adenosine reduces the skin area with increased sensitivity surrounding the injury.
-
Anesthesia and analgesia · Mar 1999
Randomized Controlled Trial Comparative Study Clinical TrialArterial oxygenation during one-lung ventilation: combined versus general anesthesia.
The optimal anesthetic management of patients undergoing thoracotomy for pulmonary resection has not been definitely determined. We evaluated whether general i.v. anesthesia (propofol-fentanyl) provides superior PaO2 during one-lung ventilation (OLV) compared with thoracic epidural anesthesia (TEA) with supplemental local and general anesthetics. We studied 60 patients who had prolonged periods of OLV for elective thoracic surgery for lung cancer and who were prospectively randomized into two groups. In 30 patients (GA group), fentanyl/propofol/rocuronium anesthesia was used. Another 30 patients (TEA group) were anesthetized with propofol/rocuronium/epidural thoracic bupivacaine 0.5%. A double-lumen endotracheal tube was inserted, and mechanical ventilation with 100% oxygen was used during the entire study. Arterial and venous blood gases were recorded before surgery in a lateral position with two-lung ventilation, 15 and 30 min after OLV (OLV + 15 and OLV + 30, respectively) in all patients. We measured PaO2, venous central oxygen tension, arterial and central venous oxygen saturation, venous admixture percentage (Qs/Qt%), and arterial and central venous oxygen content. The mean values for PaO2 during OLV in the GA group after 15 min (175 mm Hg) and 30 min (182 mm Hg) were significantly (P < 0.05) higher compared with the TEA group (120 and 118 mm Hg, respectively). Furthermore, Qs/Qt% was significantly (P < 0.05) increased in the TEA group during OLV. There were no other significant differences. We conclude that using the TEA regimen is associated with a lower PaO2 and a larger intrapulmonary shunt during OLV than with total i.v. anesthesia alone. ⋯ Sixty patients undergoing elective lung surgery during a prolonged period of intraoperative one-lung ventilation were studied and randomized to receive general i.v. anesthesia or general i.v. anesthesia combined with thoracic epidural anesthesia. The arterial oxygenation in the first group was better than that in the second group during one-lung ventilation.
-
Anesthesia and analgesia · Mar 1999
Randomized Controlled Trial Clinical TrialContinuous measurement of cerebral oxygenation by near infrared spectroscopy during induction of anesthesia.
Near infrared spectroscopy (NIRS) measures tissue oxygenation continuously at the bedside. Major disturbances of cerebral oxygenation can be detected by using NIRS, but the ability to observe smaller changes is poorly documented. Although anesthetics generally depress cerebral metabolism and enhance oxygen delivery, the administration of etomidate has been associated with cerebral desaturation. We used this difference to study the ability of NIRS to detect the small changes associated with the onset of anesthesia. Thirty-six healthy patients were randomly allocated to have anesthesia induced with either etomidate, propofol, or thiopental. We found that there was a temporal association between the onset of anesthesia and NIRS-derived indices of cerebral oxygenation. Etomidate was associated with a decrease in cerebral oxygenation, whereas propofol and thiopental were associated with an increase in cerebral oxygenation. We conclude that NIRS is capable of detecting the small changes in cerebral oxygenation associated with the induction of general anesthesia and shows promise as a bedside investigational tool for the noninvasive assessment of cerebral oxygenation. ⋯ We conclude that near infrared spectroscopy is capable of detecting the small changes in cerebral oxygenation associated with the induction of general anesthesia and shows promise as a bedside investigational tool for the noninvasive assessment of cerebral oxygenation.
-
Anesthesia and analgesia · Mar 1999
Randomized Controlled Trial Clinical TrialThe effect of heart rate control on myocardial ischemia among high-risk patients after vascular surgery.
Patients undergoing vascular surgery have a high risk of suffering major postoperative cardiac events. Preoperative myocardial ischemia as detected by Holter monitoring identifies a high-risk subgroup whose postoperative ischemia, similarly detected, seems to herald major cardiac events. In this study, we determined whether systematic, patient-specific postoperative heart rate control with beta-adrenergic blocker therapy decreases the incidence of postoperative ischemia among high-risk vascular surgery patients. A total of 26 of 150 patients who underwent elective vascular surgery and were monitored preoperatively by 24-h Holter were found to have significant myocardial ischemia as defined by ST-segment depression. The minimal heart rate at which this ST-segment depression occurred was identified (ischemic threshold), and these 26 patients were then randomized to receive continuous i.v. beta-blockade with esmolol or placebo plus usual medical therapy, aiming to reduce the postoperative heart rate to 20% below the ischemic threshold. All patients were monitored by Holter for 48 h postoperatively. Postoperative Holter readings were analyzed for the incidence of ischemia and for the number of hours during which heart rate was controlled below the ischemia threshold. Patients had a median of two episodes of preoperative ischemia lasting a median of 30 min (range 1-155 min). A total of 15 patients were randomized to receive esmolol, and 11 were randomized to receive placebo. The two groups were comparable with respect to clinical characteristics and incidence and duration of preoperative ischemia. Ischemia persisted in the postoperative period in 8 of 11 placebo patients (73%), but only 5 of 15 esmolol patients (33%) (P < 0.05). Of the 15 esmolol patients, 9 had mean heart rates below the ischemic threshold, and all 9 had no postoperative ischemia. A total of 4 of 11 placebo patients had mean heart rates below the ischemic threshold, and 3 of the 4 had no postoperative ischemia. There were two postoperative cardiac events among patients who had postoperative ischemia (one placebo, one esmolol) and whose mean heart rates exceeded the ischemic threshold. Our data suggest that patient-specific, strict heart rate control aiming for a predefined target based on individual preoperative ischemic threshold was associated with a significant reduction and frequent elimination of postoperative myocardial ischemia among high-risk patients and provide a rationale for a larger trial to examine this strategy's effect on cardiac risk. ⋯ Patients who undergo peripheral vascular surgery often experience transient cardiac complications and/or permanent heart damage just after surgery because of inadequate myocardial blood flow. In this study, we identified patients at high risk of cardiac complications after vascular surgery and showed that if their heart rate was carefully controlled for 48 h after surgery, myocardial ischemia, a common marker of heart injury, was markedly reduced.