Anesthesia and analgesia
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Anesthesia and analgesia · May 2002
Randomized Controlled Trial Clinical TrialIsoflurane requirements during combined general/epidural anesthesia for major abdominal surgery.
We evaluated the effects of bupivacaine on the requirements for thiopental and isoflurane during combined general/epidural anesthesia. Sixty patients scheduled for colon resection were randomly distributed into six groups that received, before the induction of anesthesia, an epidural (T9-10) bolus (8 mL) followed by an infusion (8 mL/h) of saline (Groups 1 and 4), bupivacaine 0.0625% plus fentanyl 2 microg/mL (Groups 2 and 5), or bupivacaine 0.125% plus fentanyl 2 microg/mL (Groups 3 and 6). We evaluated the amount of thiopental needed to abolish the eyelid reflex and the percentage of isoflurane required to maintain the bispectral index (BIS) between 50 and 60 (Groups 1-3) or the mean arterial blood pressure (MAP) within 20% of basal values (Groups 4-6). All groups required similar doses of thiopental (5 mg/kg); the time of evaluation, but not epidural treatment, had a significant effect (P < 0.0001) on BIS and MAP. After tracheal intubation, MAP and BIS increased by 18% and 49%, respectively (P < 0.05). In the bupivacaine groups, isoflurane requirements similarly decreased by 35% (P < 0.03). For BIS and MAP, the epidural treatment (P < 0.02) and type of evaluation (P < 0.03) had a significant effect; MAP was lower (P < 0.05) with 0.125% bupivacaine. We conclude that epidural bupivacaine does not alter the thiopental dose, but it decreases isoflurane requirements by 35%. This study demonstrates that both doses of bupivacaine and fentanyl induce similar isoflurane-sparing effects. However, patients receiving 0.125% bupivacaine showed lower values of MAP when compared with controls, and thus bupivacaine 0.0625% should be favored during combined anesthesia. ⋯ In patients undergoing colon resection under combined anesthesia, isoflurane requirements were assessed by changes in blood pressure or bispectral index. Epidural bupivacaine at concentrations of 0.125% or 0.0625% (each with 2 mg/mL of fentanyl) induced the same sparing of isoflurane (35%). The smaller dose produced less hypotension and should be favored.
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Anesthesia and analgesia · May 2002
Randomized Controlled Trial Clinical TrialAn inhalation bolus of sevoflurane versus an intravenous bolus of remifentanil for controlling hemodynamic responses to surgical stress during major surgery: a prospective randomized trial.
We studied 120 patients scheduled for elective major thoracic or abdominal surgery, randomized into 2 groups: a Sevoflurane group (n = 63) and a Remifentanil group (n = 57). Heart rate (HR) and mean arterial pressure (MAP) are indicative of sympathetic response to surgical stress. A positive response was defined as a 15% increase in the HR and MAP above baseline measurements. When a positive response occurred, in the Sevoflurane group we administered a bolus dose of 8% sevoflurane (fresh gas flow 6 L/min) and in the Remifentanil group, an IV bolus dose of remifentanil 1 microg x kg(-1) x min(-1), which was maintained until MAP and HR returned to baseline measurements (effective bolus). If, after a bolus dose, a decrease in MAP and/or HR of >15% occurred with respect to baseline values, the response was considered to be excessive. The bolus dose was ineffective in 4.8% of the responses in the Sevoflurane group and in 17.8% of the responses in the Remifentanil group (P < 0.05). In the Sevoflurane group, an excessive effect occurred in 12% of responses, and in 26.7% in the Remifentanil group (P < 0.05). An inhalation bolus of sevoflurane seems to be more effective than an IV remifentanil bolus during maintenance, with more effective control of hemodynamic responses to surgical stress. ⋯ We compared an inhalation bolus of sevoflurane with remifentanil for managing hemodynamic responses to major abdominal or thoracic surgery. This prospective, randomized trial demonstrated better results with sevoflurane.
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Anesthesia and analgesia · May 2002
Randomized Controlled Trial Clinical TrialMild core hypothermia and anesthetic requirement for loss of responsiveness during propofol anesthesia for craniotomy.
Mild hypothermia may be induced during neurosurgery for brain protection. However, its effect on propofol requirement has not been defined. Accordingly, we tested the hypothesis that 3 degrees C of core hypothermia decreases the propofol blood concentration at which patients respond to command (CP50-awake) in neurosurgical patients. Forty patients were anesthetized with alfentanil 50 microg/kg i.v., nitrous oxide, propofol target-controlled infusion, and rocuronium. The bispectral index (version 3.12) was monitored continuously. Patients were randomized to a core temperature of 34 degrees C or 37 degrees C. At the end of surgery, neuromuscular blockade was reversed, nitrous oxide was ceased, and propofol was infused to achieve a blood target determined by the previous patient's response. Responsiveness to command was assessed 15 min later. Results were analyzed with logistic regression models; P < 0.05 was considered statistically significant. The CP50-awake of propofol was 3.05 microg/mL (95% confidence interval, 2.34-3.66). Propofol concentration, but not core temperature, predicted loss of response to command (odds ratio, 11.76; 95% confidence interval, 2.40-57.63; P < 0.01). Core temperature did not alter the relationship between bispectral index and response to command. Propofol infusion regimens may not require adjustment during mild hypothermia. ⋯ Neurosurgical patients may be allowed to become mildly hypothermic during anesthesia in an effort to provide brain protection. Propofol maintenance infusion doses may not require adjustment in these patients.
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Anesthesia and analgesia · May 2002
Randomized Controlled Trial Clinical TrialOndansetron orally disintegrating tablet versus placebo for the prevention of postdischarge nausea and vomiting after ambulatory surgery.
Ondansetron orally disintegrating tablet reduces postdischarge nausea and vomiting and improves patient satisfaction with postoperative nausea and vomiting management.
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Anesthesia and analgesia · May 2002
Continuous epidural infusion of 0.05% bupivacaine plus hydromorphone for labor analgesia: an observational assessment in 1830 parturients.
We evaluated a continuous epidural infusion containing bupivacaine 0.05% plus the opioid hydromorphone in 1830 women requesting pain relief during labor and delivery. The infusion provided effective analgesia with minimal adverse events for patients differing in parity and at varying stages of labor. Pain relief was maintained in most patients without the need for epidural reinforcement with more concentrated doses of local anesthetic.