Anesthesia and analgesia
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Anesthesia and analgesia · Jun 2003
Randomized Controlled Trial Clinical TrialThe effects of epidural and general anesthesia on tissue oxygenation.
The risk of wound infections is inversely related to subcutaneous tissue oxygen tension. General anesthesia increases local blood flow by direct vasodilation and central inhibition of thermoregulatory vasoconstriction. Epidural anesthesia can increase perfusion in blocked regions by decreasing sympathetic tone. We therefore tested the hypothesis that epidural anesthesia increases tissue oxygen tension in awake and anesthetized subjects. Fifteen healthy volunteers underwent epidural, general, and combined epidural and general anesthesia. Subcutaneous tissue oxygen tension was measured using tonometers in the lateral upper arm and the lateral thigh. Epidural anesthesia to a T10 level was maintained with 0.75% mepivacaine. General anesthesia was maintained with 1.5% sevoflurane in 30% oxygen; 30% inspired oxygen was given via a sealed facemask during baseline and epidural anesthesia. Baseline subcutaneous tissue oxygen tensions for arm and thigh were 57 +/- 11 and 54 +/- 8 mm Hg, respectively. Epidural anesthesia significantly increased tissue oxygenation in the thigh by 9 mm Hg, to 63 +/- 7 mm Hg, without increasing arm oxygenation. Tissue oxygenation in the arm and thigh were similar during general anesthesia alone, 58 +/- 11 and 63 +/- 12 mm Hg. Arm oxygenation remained unchanged with the addition of epidural anesthesia; however, thigh subcutaneous oxygen partial pressure increased 8 +/- 3 mm Hg, from 63 +/- 12 to 71 +/- 9 mm Hg. Although epidural anesthesia increased tissue oxygenation significantly with and without general anesthesia, the magnitude of this increase might be of marginal clinical importance in regard to surgical wound infections. ⋯ Epidural anesthesia significantly increased subcutaneous tissue oxygenation in the thigh both with and without general anesthesia. Although each increase was statistically significant, previous work suggests that the magnitude of these changes is unlikely to markedly reduce the risk of surgical wound infection.
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Anesthesia and analgesia · Jun 2003
Clinical TrialSmall risk of serious neurologic complications related to lumbar epidural catheter placement in anesthetized patients.
Previous studies have identified pain during needle/catheter placement or during the injection of local anesthetic as a risk factor for the development of persistent paresthesias after regional anesthetic techniques. The performance of regional blockade on anesthetized patients theoretically increases the risk of postoperative neurologic complications, because these patients are unable to respond to painful stimuli. In this study, we evaluated the frequency of neurologic complications in 4298 thoracic surgical patients undergoing lumbar epidural catheter placement while under general anesthesia. Catheters were placed immediately after the induction and tracheal intubation or on completion of the surgical procedure, before emergence. Most epidural catheters (4220, or 98.2%) were used solely for postoperative analgesia; only 78 (1.8%) epidural catheters were used for intraoperative anesthesia. In 4239 (98.6%) patients, an opioid alone was administered. The remaining 56 (1.3%) patients received a local anesthetic or local anesthetic/opioid mixture epidurally. Analgesia was graded as excellent or good in 92.2% of patients. Side effects included sedation in 455 (10.6%), nausea or emesis in 328 (7.6%), pruritus in 116 (2.7%), and respiratory depression (pH
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Anesthesia and analgesia · Jun 2003
Clinical TrialDiluent volume for epidural fentanyl and its effect on analgesia in early labor.
Epidural fentanyl after a lidocaine and epinephrine test dose provides adequate analgesia and allows for ambulation during early labor. We designed the current study to determine the influence of the diluent volume of the epidural fentanyl bolus (e.g., whether it has an effect on the onset and duration of analgesia). Sixty laboring primigravid women received a 3-mL epidural test dose of lidocaine with epinephrine and then received a fentanyl 100- micro g bolus in either a 2-mL, 10-mL, or 20-mL volume. Pain scores and side effects were recorded for each patient. The onset of analgesia was similar in all three groups. The mean duration before re-dose was not significantly different in the 2-mL group (108 +/- 40 min), the 10-mL group (126 +/- 57 min), or the 20-mL group (126 +/- 41 min). No patient in any group experienced any detectable motor block; one patient (2-mL group) complained of mild knee weakness and was not allowed to ambulate. In early laboring patients, the volume in which 100 micro g of epidural fentanyl (after a lidocaine-epinephrine test dose) is administered does not affect the onset or duration of analgesia, nor does it affect the ability to ambulate. ⋯ In early laboring patients, the volume in which 100 micro g of epidural fentanyl (after a lidocaine-epinephrine test dose) is administered does not affect the onset or duration of ambulatory analgesia.
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Anesthesia and analgesia · Jun 2003
Comment Letter Case ReportsAnesthesia of a patient with cured myasthenia gravis.
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Anesthesia and analgesia · Jun 2003
Survival with full neurologic recovery after prolonged cardiopulmonary resuscitation with a combination of vasopressin and epinephrine in pigs.
We sought to determine the effects of a combination of vasopressin and epinephrine on neurologic recovery in comparison with epinephrine alone and saline placebo alone in an established porcine model of prolonged cardiopulmonary resuscitation (CPR). After 4 min of cardiac arrest, followed by 3 min of basic life support CPR, 17 animals were randomly assigned to receive, every 5 min, either a combination of vasopressin and epinephrine (vasopressin [IU/kg]/epinephrine [ micro g/kg]: 0.4/45, 0.4/45, and 0.8/45; n = 6), epinephrine alone (45, 45, and 200 micro g/kg; n = 6), or saline placebo alone (n = 5). After 22 min of cardiac arrest, including 18 min of CPR, defibrillation was attempted to achieve the return of spontaneous circulation. Aortic diastolic pressure was significantly (P < 0.01) increased 90 s after each of 3 vasopressin/epinephrine injections versus epinephrine alone versus saline placebo alone (mean +/- SEM: 69 +/- 3 mm Hg versus 45 +/- 3 mm Hg versus 29 +/- 2 mm Hg, 63 +/- 4 mm Hg versus 27 +/- 3 mm Hg versus 23 +/- 1 mm Hg, and 52 +/- 4 mm Hg versus 21 +/- 3 mm Hg versus 16 +/- 3 mm Hg, respectively). Spontaneous circulation was restored in six of six vasopressin/epinephrine pigs, whereas six of six epinephrine and five of five saline placebo pigs died (P < 0.01). Neurologic evaluation 24 h after successful resuscitation revealed only an unsteady gait and was normal 5 days after the experiment in all vasopressin/epinephrine-treated animals. In conclusion, in this porcine model of prolonged CPR, repeated vasopressin/epinephrine administration, but not epinephrine or saline placebo alone, ensured long-term survival with full neurologic recovery. ⋯ We present a study to evaluate the effects of a combination of vasopressin and epinephrine during prolonged cardiopulmonary resuscitation on neurological outcome in pigs. We found that all pigs treated with a combination of vasopressin and epinephrine could be resuscitated and had full neurologic recovery observed over an entire period of 5 days.