Anesthesia and analgesia
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Anesthesia and analgesia · Mar 2002
Randomized Controlled Trial Clinical TrialPhysostigmine does not antagonize sevoflurane anesthesia assessed by bispectral index or enhances recovery.
In this double-blinded study, we investigated the effect of physostigmine on sevoflurane anesthesia and recovery. Forty female patients scheduled for breast biopsy were randomly assigned to receive either physostigmine 2 mg IV or an equal volume of normal saline after skin closure. Anesthesia was induced and maintained with sevoflurane in oxygen. After skin closure, a steady state of 0.6% inspired and end-tidal sevoflurane concentration was obtained, heart rate, blood pressure, and Bispectral index (BIS) baseline values were recorded, and physostigmine or normal saline was administered. Hemodynamics and BIS values were also recorded 5, 8, and 10 min after treatments. Anesthesia was discontinued, and orientation, sedation, sitting ability, and "picking up matches" scores were recorded immediately after extubation and 15 and 30 min later. No differences were found between the two groups in BIS (69, 70, 70, and 71 in the Physostigmine group versus 70, 74, 75, and 76 in the Control group) or blood pressure. Only heart rate was increased 8 min after physostigmine (P < 0.05 versus the control). Scores assessing early recovery were similar in the two groups at all time points. We conclude that physostigmine does not change BIS or enhance recovery after sevoflurane anesthesia. ⋯ This double-blinded, randomized study investigated the impact of physostigmine of BIS values during 0.6% sevoflurane anesthesia as well as in the postoperative recovery, when sevoflurane is administered as a sole anesthetic. Physostigmine has no effect on BIS values or on the tests assessing recovery.
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Anesthesia and analgesia · Mar 2002
Randomized Controlled Trial Clinical TrialPreoperative clonidine blunts hyperadrenergic and hyperdynamic responses to prolonged tourniquet pressure during general anesthesia.
Although the mechanism of tourniquet-induced hypertension is still unclear, plasma norepinephrine concentrations continuously increase in parallel to arterial blood pressure during tourniquet inflation. Clonidine attenuates hyperadrenergic and hyperdynamic responses. We investigated the effects of clonidine on prolonged tourniquet inflation. Twenty-nine patients scheduled for elective orthopedic surgery were randomly assigned to receive IV clonidine (3 microg/kg; n = 14) or placebo (n = 15) before tourniquet inflation of the lower limbs under general anesthesia in a double-blinded manner. Arterial blood pressure, heart rate, epinephrine, and norepinephrine plasma concentrations were measured before tourniquet inflation, 60 min after tourniquet inflation, just before tourniquet deflation, and 20 min after tourniquet deflation. Mean arterial blood pressure and norepinephrine plasma-concentrations were significantly lower in the Clonidine group compared with Control after 60 min tourniquet inflation (P = 0.016; P = 0.006). Immediately before deflation of the tourniquet, the difference for mean arterial pressure between groups was even more pronounced (P = 0.005). Twenty minutes after deflation mean arterial blood pressure in the Control group was still increased and significantly higher compared with the Clonidine group (P = 0.002). In conclusion, preoperative IV clonidine blunts hyperadrenergic and hyperdynamic responses resulting from prolonged tourniquet inflation under general anesthesia in ASA class I--II patients. ⋯ Tourniquet inflation is associated with a continuous increase in arterial blood pressure and sympathetic outflow. This study shows that IV clonidine effectively blunts increases of both arterial blood pressure and plasma norepinephrine concentrations.
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Anesthesia and analgesia · Mar 2002
Randomized Controlled Trial Clinical TrialThe primary action of epidural fentanyl after cesarean delivery is via a spinal mechanism.
We tested the hypotheses that the primary mechanism of action of epidural fentanyl after cesarean delivery is spinal and that very small dose epidural bupivacaine with epinephrine enhances this effect. After elective cesarean delivery, 100 parturients were randomized in a double-blinded design to four groups. Group I and II patients received a continuous 12 mL/h epidural infusion of bupivacaine 0.015% with epinephrine 1 microg/mL for 48 h and Groups III and IV received a 12 mL/h saline epidural infusion instead. Fentanyl 20 microg/mL was administered via a patient-controlled analgesia device either into the epidural infusion (Groups I and IV) or IV (Groups II and III). When compared to patients receiving epidural fentanyl, those receiving IV fentanyl required larger mean infused and total dose of fentanyl (P < 0.0001), reported more pain (P < 0.001), and had a more frequent incidence of excessive sedation (P < 0.01), nausea (P < 0.01), and vomiting (P < 0.01). Plasma concentrations of fentanyl were larger for Group II and III than for Groups I and IV (P < 0.001) at 24 and 48 h. Our results support the hypothesis that the primary mechanism of analgesia of epidural fentanyl after cesarean delivery is spinal. Our data also show that the total required dose of epidural, but not IV, fentanyl is reduced by very small dose epidural bupivacaine and epinephrine (Group I versus Group IV, P < 0.02 and Group II vs Group III, not significant). ⋯ Fentanyl administered epidurally to parturients after cesarean delivery has a primarily spinal mechanism of action and this effect is enhanced by very small dose epidural bupivacaine and epinephrine.
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Anesthesia and analgesia · Mar 2002
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of two tracheal intubation techniques with Trachlight and Fastrach in patients with cervical spine disorders.
Optimal airway management strategies in patients with an unstable cervical spine remain controversial. A newly designed lightwand device (Trachlight) or an intubating laryngeal mask (Fastrach) may avoid hyperextension of the neck. However, there are few objective data that guide us in selecting the appropriate devices. We conducted a prospective randomized study in 148 patients who received general anesthesia for whom the operations were related to the clinical and/or radiographic evidence of cervical abnormality. Trachlight or Fastrach was used for tracheal intubation with the head and neck held in a neutral position. In the Trachlight group, intubation was successful at the first attempt in 67 of 74 (90.5%) cases and at the second attempt in 5 (6.8%) cases. In contrast, in the Fastrach group, 54 of 74 (73.0%) patients were intubated within our protocol. The mean time for successful tracheal intubation at the first attempt was significantly shorter in the Trachlight group than in the Fastrach group. The Trachlight may be more advantageous for orotracheal intubation in patients with cervical spine disorders than the Fastrach with respect to reliability, rapidity, and safety. ⋯ The Trachlight may be more advantageous for orotracheal intubation in patients with cervical spine disorders than the Fastrach with respect to reliability, rapidity and safety.
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Anesthesia and analgesia · Mar 2002
Randomized Controlled Trial Comparative Study Clinical TrialSelective spinal anesthesia versus desflurane anesthesia in short duration outpatient gynecological laparoscopy: a pharmacoeconomic comparison.
We compared the cost and effectiveness of selective spinal anesthesia (SSA) with a desflurane-based general anesthetic (DES) for outpatient gynecological laparoscopy. A prospective analysis was undertaken of 10 patients randomized to receive SSA and compared with 10 patients randomized to receive DES. The groups were well matched in their demographic characteristics. The mean cost (in 2000 Canadian dollar values) of anesthesia supplies, drugs, and nursing for the SSA group of $62.31 was less than that for the DES group of $92.31 (P < 0.01). Recovery costs of both groups were similar. Time to administer anesthesia and time spent in the postanesthetic care unit were also similar. Postoperative analgesia was required by 50% of the DES group but in no patient receiving SSA (P < 0.01). SSA is a cost-effective alternative to DES in these patients. ⋯ Small-dose spinal anesthesia is an effective alternative to a desflurane general anesthetic in terms of cost and recovery profiles in ambulatory gynecological laparoscopy.