Anesthesia and analgesia
-
Anesthesia and analgesia · Aug 1996
Randomized Controlled Trial Comparative Study Clinical TrialMechanism of action of an epidural top-up in combined spinal epidural anesthesia.
The purpose of this study was to elucidate the mechanism of action by which an epidural top-up reinforces anesthesia in combined spinal epidural anesthesia. Thirty patients scheduled to undergo lower limb orthopedic surgery were randomly allocated to three groups of 10 patients each. In all patients, a 16-gauge Tuohy needle was introduced into the epidural space. ⋯ In Group 3 there was a nonsignificant increase of 0.3 +/- 0.5 segments. Intergroup comparisons showed that this increase in Group 1 was significant compared with those in Groups 2 and 3, and that the increase in Group 2 was significant compared with that in Group 3. We conclude that the mechanism of action by which an epidural top-up reinforces anesthesia in combined spinal epidural anesthesia can be explained partly by an epidural volume effect and partly by an effect of the local anesthetic itself.
-
Anesthesia and analgesia · Aug 1996
Randomized Controlled Trial Clinical TrialLarge-dose intrathecal morphine for coronary artery bypass grafting.
Aggressive control of pain during the immediate postoperative period after cardiac surgery, associated with decreased blood catecholamine levels, may decrease morbidity and mortality. This study investigated the use of large-dose intrathecal morphine for cardiac surgery and its effect on postoperative analgesic requirements and blood catecholamine levels. Patients were randomized to receive either 4.0 mg of intrathecal morphine (Group MS) or intrathecal saline placebo (Group NS). ⋯ Patients in Group MS required significantly less postoperative intravenous morphine than patients in Group NS. Although perioperative norepinephrine and epinephrine levels in Group MS patients tended to be lower than Group NS patients, the differences were not statistically significant. In conclusion, large-dose intrathecal morphine initiates reliable postoperative analgesia but does not reliably attenuate the stress response during and after cardiac surgery.
-
Anesthesia and analgesia · Aug 1996
Randomized Controlled Trial Comparative Study Clinical TrialIntracranial pressure and hemodynamic effects of remifentanil versus alfentanil in patients undergoing supratentorial craniotomy.
Remifentanil hydrochloride is an ultra-short-acting esterase metabolized mu-opioid receptor agonist. The purpose of this study was to provide preliminary information regarding the effects of this drug on intracranial pressure (ICP) and mean arterial pressure (MAP) in patients scheduled for craniotomy. Twenty-six patients undergoing excision of supratentorial space-occupying lesions were anesthetized with 0.3-0.8 vol% isoflurane in a 2:1 mixture of nitrous oxide:oxygen. ⋯ Both drugs were associated with a dose-dependent decrease in MAP. Remifentanil was 31 times more potent than alfentanil for effects on MAP. We conclude that remifentanil produces similar cerebral perfusion pressure effects as does alfentanil.
-
Anesthesia and analgesia · Aug 1996
Randomized Controlled Trial Clinical TrialThe analgesic efficacy and adverse effects of continuous epidural sufentanil and bupivacaine infusion after thoracotomy.
We investigated analgesia and the adverse effects of epidural sufentanil infusion in a double-blind randomized study of 37 patients undergoing thoracic surgery. Sufentanil 1 microgram/mL was administered at a thoracic (Ts, n = 12) or lumbar level (Ls, n = 11), or combined with bupivacaine 1 mg/mL at a thoracic level (Tsb, n = 14). Postoperatively, the epidural infusion rate was titrated (4-20 mL/h) according to the visual analog pain scale when assessed during function (VAS-F) or the occurrence of side effects. ⋯ The slopes of the ventilatory response (minute ventilation [VE], inspiratory flow, and mouth occlusion pressure at 0.1 s [P0.1]) to 7% CO2 decreased during treatment in Ls, Ts, and Tsb groups at the most by 73%, 55%, and 52% (not significant [NS] between groups), 59%, 45%, and 38% (NS between groups), and 81%, 43%, and 18% (Ls > Tsb), respectively. Twenty-four hours after discontinuation of the epidural infusion, there was a complete recovery of the VE, inspiratory flow, and P0.1 response to CO2 in the Tsb group only. The study shows that, after thoracotomy, epidural sufentanil analgesia is optimal when tailored to the site of nociceptive input and combined with bupivacaine.
-
Anesthesia and analgesia · Aug 1996
Randomized Controlled Trial Clinical TrialThe pharmacokinetics of continuous epidural sufentanil and bupivacaine infusion after thoracotomy.
In a double-blind, randomized study in patients undergoing thoracic surgery the plasma and cerebrospinal fluid (CSF) pharmacokinetics of the epidural sufentanil were studied by using radioimmunoassay analysis. Sufentanil was given as an infusion (1 microgram/mL) at the lumbar (Ls; n = 11), or thoracic (Ts; n = 12) level, or epidural sufentanil combined with bupivacaine (1 mg/ mL) at the thoracic level (Tsb; n = 14). Postoperatively, the infusion was adjusted to optimize analgesia. ⋯ The terminal elimination half-life of sufentanil in CSF was 7.2 +/- 0.6 h. During steady state the CSF concentrations were not homogeneously distributed and they were higher than those in plasma. These pharmacokinetic findings support the concept that epidural sufentanil analgesia is optimal when administered segmentally and tailored to the surgical incision.