Anesthesia and analgesia
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Anesthesia and analgesia · Oct 2002
Randomized Controlled Trial Comparative Study Clinical TrialFour-injection brachial plexus block using peripheral nerve stimulator: a comparison between axillary and humeral approaches.
We conducted this prospective, randomized study to compare the success rate, performance time, and onset time of surgical anesthesia of a four-injection brachial plexus block performed at the axillary (Group Axillary; n = 50) or at the humeral (Group Humeral; n = 50) level using a peripheral nerve stimulator. All patients received 40 mL of a mixture of equal parts of 0.5% bupivacaine and 2% lidocaine. Four patients in Group Axillary and two in Group Humeral were excluded from the study because all of the four nerves were not localized in the allotted time. The incidence of complete block (91% versus 89%), defined as block of all the sensory areas below the elbow, and the onset time of sensory block (15 +/- 6 min versus 16 +/- 7 min) were not different between the groups. The performance time was shorter in Group Humeral (7 +/- 2 min versus 8 +/- 2 min; P < 0.005). Block performance pain was lower in Group Axillary patients (16 +/- 9 min versus 23 +/- 12 min; P < 0.005). For four-injection brachial plexus block, we conclude that both the axillary and the humeral approaches provide a high success rate and a rapid onset of sensory anesthesia; the differences found between the groups could be considered clinically unimportant. ⋯ Two methods of brachial plexus block using a nerve-stimulator were compared in a prospective study. A four-injection technique was performed at the axillary or at the humeral level. Both approaches provided a fast onset and a high success rate. The differences found between the groups could be considered clinically unimportant.
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Anesthesia and analgesia · Oct 2002
Flumazenil recovers diaphragm muscle dysfunction caused by midazolam in dogs.
We studied the effects of flumazenil on diaphragm muscle dysfunction caused by midazolam in dogs. Animals were divided into three groups of eight each. In each group, anesthetic doses (0.1 mg/kg initial dose plus 0.5 mg. kg(-1). h(-1) maintenance dose) of midazolam were administered for 60 min. Immediately after the end of midazolam administration, Group 1 received no study drug; Group 2 was infused small-dose (0.004 mg. kg(-1). h(-1)) flumazenil; Group 3 was infused with large-dose (0.02 mg. kg(-1). h(-1)) flumazenil. We assessed diaphragm muscle function (contractility and electrical activity) by transdiaphragmatic pressure (Pdi) and integrated electrical activity of the diaphragm (Edi). After midazolam was administered in each group, Pdi at low-frequency (20-Hz) and high-frequency (100-Hz) stimulation decreased from baseline values (P < 0.05), and values of Edi at 100-Hz stimulation were less than those obtained during baseline (P < 0.05). In Group 1, Pdi and Edi to each stimulus did not change from midazolam-induced values. In Groups 2 and 3, with an infusion of flumazenil, Pdi at both stimuli and Edi at 100-Hz stimulation increased from midazolam-induced values (P < 0.05). The increase in Pdi and Edi was more in Group 3 than in Group 2 (P < 0.05). We conclude that flumazenil recovers the diaphragm muscle dysfunction (reduced contractility and inhibited electrical activity) caused by anesthetic doses of midazolam in dogs. ⋯ In dogs, flumazenil recovers diaphragm muscle dysfunction (reduced contractility and inhibited electrical activity) caused by midazolam in a dose-related manner.
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Anesthesia and analgesia · Oct 2002
Randomized Controlled Trial Comparative Study Clinical TrialRemifentanil, fentanyl, and cardiac surgery: a double-blinded, randomized, controlled trial of costs and outcomes.
Remifentanil may be beneficial in patients undergoing coronary artery bypass graft surgery, by promoting hemodynamic stability, reducing drug requirements, and attenuating the neurohumoral "stress response." We enrolled 77 cardiac surgical patients in a double-blinded, randomized trial and randomly allocated them to one of three groups: remifentanil infusion at 0.83 micro g. kg(-1). min(-1) (Group R); fentanyl bolus, small dose, at 12 micro g/kg (Group FLD); and fentanyl bolus, moderate dose, at 24 micro g/kg (Group FMD). We found a significant difference in the median time to tracheal extubation: Group FLD, 6.5 h; Group R, 7.3 h; and Group FMD, 9.7 h (P = 0.025). Group R patients had similar times to those of Groups FLD (P = 0.14) and FMD (P = 0.30). Group FLD patients had a longer length of hospital stay (P = 0.030). Patients in Group R had a significantly infrequent rate of hypertension but a frequent rate of hypotension (P < 0.01). The urinary cortisol excretion was larger in Group FLD patients (P < 0.0005), and urine flow was smaller (P < 0.0005). Remifentanil was associated with a propofol dose reduction (P = 0.0005) and a concomitant higher bispectral index (P = 0.032). Three Group FLD patients, but none in groups FMD and R, had postoperative myocardial infarctions (P = 0.032). Remifentanil has larger drug acquisition costs but does not increase the total hospital costs associated with cardiac surgery. ⋯ Remifentanil did not significantly reduce the duration of tracheal intubation after cardiac surgery. Remifentanil, when compared with fentanyl (total doses of approximately 15 and 28 micro g/kg), blunts the hypertensive responses associated with cardiac surgery but is associated with more hypotension; when compared with fentanyl 15 micro g/kg, remifentanil reduces cortisol excretion. Larger-dose opioids (remifentanil 0.85 micro g. kg(-1). min(-1) or fentanyl 28 micro g/kg) were associated with a decreased rate of myocardial infarction after cardiac surgery.
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Anesthesia and analgesia · Oct 2002
Randomized Controlled Trial Comparative Study Clinical TrialThe analgesic effect of gabapentin and mexiletine after breast surgery for cancer.
We investigated the analgesic efficacy of mexiletine and gabapentin on acute and chronic pain associated with cancer breast surgery in 75 patients. They were randomized to receive, in a double-blinded manner, mexiletine 600 mg/d, gabapentin 1200 mg/d, or placebo for 10 days. Anesthesia was standardized, and all patients had access to routine postoperative analgesics on demand. The visual analog scale score assessed pain at rest and after movement. Three months later, all patients were interviewed to identify intensity of chronic pain and analgesic requirements. Mexiletine and gabapentin reduced codeine consumed from the second to tenth day by 50% (P = 0.029; P = 0.018 and P = 0.035 for mexiletine versus control and gabapentin versus control comparisons, respectively). Total paracetamol consumption was also reduced during the same time (P = 0.0085; P = 0.007 and P = 0.011 for the mexiletine and gabapentin groups when compared with the control, respectively). Pain at rest and after movement was reduced by both drugs on the third postoperative day. Pain after movement also was reduced by gabapentin between the second and fifth postoperative day. Three months later, the incidence of chronic pain, its intensity, and need for analgesics were not affected by either treatment. However, burning pain was more frequent in the control group (P = 0.033). ⋯ Patients undergoing breast surgery for cancer may develop chronic pain. We evaluated the effect of mexiletine and gabapentin on the acute and chronic pain after breast surgery for cancer. Both drugs reduced the postoperative analgesic requirements, and particularly, gabapentin reduced pain after movement. The overall incidence of chronic pain was unaffected except for burning pain.