Anesthesia and analgesia
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Anesthesia and analgesia · Jan 2004
Randomized Controlled Trial Comparative Study Clinical TrialSpinal 2-chloroprocaine: a dose-ranging study and the effect of added epinephrine.
With the availability of preservative- and antioxidant-free 2-chloroprocaine (2-CP), there may be an acceptable short-acting alternative to lidocaine for spinal anesthesia. We examined the safety, dose-response characteristics, and effects of epinephrine with spinal 2-CP. Six volunteers per group were randomized to receive 30, 45, or 60 mg of spinal 2-CP with and without epinephrine. Intensity and duration of sensory and motor blockade were assessed. When 11 of the 18 volunteers complained of vague, nonspecific flu-like symptoms, breaking of the blind revealed that all spinal anesthetics associated with the flu-like symptoms contained epinephrine. There were no complaints of flu-like symptoms in the volunteers who received 2-CP without epinephrine. No further spinal anesthetics containing epinephrine were administered, resulting in 29 anesthetics (11 with epinephrine, 18 without epinephrine.) Plain 2-CP demonstrated a dose-dependent increase in peak block height and duration of effect at all variables except time to 2-segment regression and time to regression to T10. Time to complete sensory regression with plain 2-CP was 98 +/- 20, 116 +/- 15, and 132 +/- 23 min, respectively. 2-CP with epinephrine produced times to complete sensory regression of 153 +/- 25, 162 +/- 33, and 148 +/- 29 min, respectively. Preservative and antioxidant free 2-CP can be used effectively for spinal anesthesia in doses of 30-60 mg. Epinephrine is not recommended as an adjunct because of the frequent incidence of side effects. ⋯ Hyperbaric spinal 2-chloroprocaine is effective and has an anesthetic profile appropriate for use in the surgical outpatient over the dose range of 30-60 mg without signs of transient neurologic symptoms. The addition of epinephrine is not recommended because of the frequent incidence of side effects.
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Anesthesia and analgesia · Jan 2004
Randomized Controlled Trial Clinical TrialSpinal 2-chloroprocaine: the effect of added dextrose.
Spinal 2-chloroprocaine is being investigated as an alternative short-acting spinal anesthetic to replace lidocaine for outpatient surgery. Adding dextrose increases the baricity of solutions and alters the characteristics of spinal anesthesia. In this study, we compared 2-chloroprocaine spinal anesthesia performed with or without the addition of dextrose (1.1%). Eight volunteers underwent 2 spinal anesthetics, receiving 40 mg 2-chloroprocaine (2 mL, 2%) with 0.25 mL saline with one and 0.25 mL 10% dextrose with the other in a double-blinded, randomized, balanced crossover manner. Pinprick anesthesia, tolerance to transcutaneous electrical stimulation, and tourniquet, motor strength measurements, and time to ambulation and void were assessed. Postvoid residual bladder volume was measured via ultrasound. Spinal anesthesia was successful in all subjects and regressed within 110 (80-110) min. There was no significant difference in peak height T4 (T7-C6), time to achieve peak block height (14 +/- 6 min), time for 2-segment regression (44 +/- 9 min), regression to L1 (66 +/- 12 min), tolerance of tourniquet (43 +/- 9 min), or return of motor function (81 +/- 14 min). Mean postvoid residual volume was larger with dextrose (74 +/- 67 mL versus 16 +/- 35 mL; P = 0.02). No subject reported signs of transient neurologic symptoms (TNS). In conclusion, spinal 2-chloroprocaine provides adequate potency with reliable regression, seemingly without TNS. Adding dextrose does not significantly alter spinal block characteristics but increases residual bladder dysfunction. Therefore, the addition of glucose to 2-chloroprocaine for spinal anesthesia is not necessary. ⋯ Spinal chloroprocaine provides adequate potency with reliable regression, seemingly without concerns of transient neurologic symptoms, and hence an appealing profile for outpatient surgery. The addition of dextrose does not alter peak block height or tolerance of thigh tourniquet, and increases the degree of residual bladder dysfunction.
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Anesthesia and analgesia · Jan 2004
Randomized Controlled Trial Clinical TrialThe pharmacokinetics and efficacy of ropivacaine continuous wound instillation after spine fusion surgery.
Because local anesthetic continuous wound instillation has not been evaluated after spine fusion surgery, we designed this study to determine whether this technique could enhance analgesia and improve patient outcome after posterior lumbar arthrodesis. Thirty-eight patients undergoing spine stabilization were randomly divided into two groups. The M group received a postoperative baseline IV infusion of morphine plus ketorolac for 24 h, and the R group received IV saline. In both groups, a multihole 16-gauge catheter was placed subcutaneously; in the R group, the wound was infiltrated with a solution of ropivacaine 0.5% 200 mg/40 mL, and infusion of ropivacaine 0.2% 5 mL/h was maintained for 55 h. In the M group, saline infusion was given at the same rate. Pain scores were taken at rest and on passive mobilization by nurses blinded to patient analgesic treatment. The total plasma ropivacaine concentration was evaluated. Pain scores and rescue medication requirements (diclofenac and tramadol) were significantly less in the R group than in the M group. Postoperative blood loss was less and the length of hospital stay was shorter in the R group. The ropivacaine peak total plasma concentration occurred at 24 h during infusion and was within safe limits; no toxic local anesthetic side effects were observed. These results suggest that wound infiltration and continuous instillation of ropivacaine 0.2% is effective for pain management after spine stabilization surgery. ⋯ Postoperative pain after lumbar arthrodesis is related to soft tissue and muscle dissection and to manipulations and removal at the operation site. By blocking noxious stimuli from the surgical area, infiltration and wound perfusion with ropivacaine were more effective in controlling pain than systemic analgesia.
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Anesthesia and analgesia · Jan 2004
Clinical TrialA novel infraclavicular brachial plexus block: the lateral and sagittal technique, developed by magnetic resonance imaging studies.
A new infraclavicular brachial plexus block method has the patient supine with an adducted arm. The target is any of the three cords behind the pectoralis minor muscle. The point of needle insertion is the intersection between the clavicle and the coracoid process. The needle is advanced 0 degrees -30 degrees posterior, always strictly in the sagittal plane next to the coracoid process while abutting the antero-inferior edge of the clavicle. We tested the new method using magnetic resonance imaging (MRI) in 20 adult volunteers, without inserting a needle. Combining 2 simulated needle directions by 15 degrees posterior and 0 degrees in the images of the volunteers, at least one cord in 19 of 20 volunteers was contacted. This occurred within a needle depth of 6.5 cm. In the sagittal plane of the method the shortest depth to the pleura among all volunteers was 7.5 cm. The MRI study indicates that the new infraclavicular technique may be efficient in reaching a cord of the brachial plexus, often not demanding more than two needle directions. The risk of pneumothorax should be minimal because the needle is inserted no deeper than 6.5 cm. However, this needs to be confirmed by a clinical study. ⋯ A new infraclavicular brachial plexus block method was investigated using magnetic resonance imaging without inserting needles in the volunteers. The study suggests two needle directions for performance of the block and that the risk of lung injury should be minimal. Expectations need to be confirmed by a clinical study.
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Anesthesia and analgesia · Jan 2004
Clinical TrialChronic treatment with antipsychotics enhances intraoperative core hypothermia.
Antipsychotics can induce hypothermia, but intraoperative temperature regulation in schizophrenic patients taking antipsychotics remains unclear. We investigated intraoperative temperature regulation and postoperative shivering in chronic schizophrenic patients receiving antipsychotics. We studied 30 schizophrenic patients and 30 control patients who underwent orthopedic surgery. Tympanic membrane temperatures (35.7 degrees C +/- 0.5 degrees C, 35.6 degrees C +/- 0.5 degrees C, 35.6 degrees C +/- 0.4 degrees C, 35.5 degrees C +/- 0.4 degrees C, 35.4 degrees C +/- 0.5 degrees C, and 35.4 degrees C +/- 0.3 degrees C) 15, 30, 45, 60, 75, and 90 min, respectively, after induction in schizophrenic patients were significantly (P < 0.001) lower than those (36.5 degrees C +/- 0.5 degrees C, 36.4 degrees C +/- 0.5 degrees C, 36.3 degrees C +/- 0.4 degrees C, 36.2 degrees C +/- 0.5 degrees C, 36.2 degrees C +/- 0.4 degrees C, and 36.1 degrees C +/- 0.4 degrees C) in control patients. Mean skin temperatures (31.1 degrees C +/- 0.4 degrees C [P = 0.008], 31.1 degrees C +/- 0.3 degrees C [P = 0.007], and 31.1 degrees C +/- 0.2 degrees C [P = 0.006]) 60, 75, and 90 min, respectively, after induction in schizophrenic patients were significantly lower than those (31.5 degrees C +/- 0.3 degrees C, 31.5 degrees C +/- 0.3 degrees C, and 31.5 degrees C +/- 0.3 degrees C) in control patients. Four of 30 schizophrenic patients and 7 of 30 control patients developed postanesthesia shivering. There were no significant differences within 1 h after tracheal extubation in tympanic membrane temperatures between patients who shivered and those who did not shiver. In conclusion, chronic schizophrenic patients were more hypothermic during anesthesia. The incidence of postanesthesia shivering was not significantly increased. ⋯ Antipsychotics inhibit autonomic thermoregulation. This is caused by decreased heat production, increased heat loss, and impaired central action at the hypothalamus. Thus, schizophrenic patients receiving antipsychotics may have impaired intraoperative temperature regulation.