Anesthesia and analgesia
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Anesthesia and analgesia · Dec 2001
Randomized Controlled Trial Clinical TrialThe safety of immediate extubation after abdominal aortic surgery: a prospective, randomized trial.
We performed this study to assess the safety of immediate extubation after elective abdominal aortic aneurysm surgery. Consecutive patients were prospectively randomized into two groups after surgery: Group 1 (n = 29) immediate extubation; and Group 2 (n = 21) delayed (at least 4 h) extubation. All patients were assessed by a senior anesthesiologist or intensivist before extubation. The following data were collected: preoperative-demographics, presence of comorbid disease, body mass index, hemoglobin level, heart rate, and blood pressure; intraoperative-duration of surgery and cross-clamping, blood loss, amount of crystalloids, colloids, and blood transfused, temperature at end of procedure, urine output, and complications; and postoperative-time to extubation, scores on the Acute Physiology and Chronic Health Evaluation-II and Therapeutic Intervention Scoring System, total fentanyl dose, and complications. Outcome variables were length of intensive care unit and hospital stay and 28-day mortality. The results showed no significant differences in preoperative or intraoperative variables between the groups, apart from a longer duration of surgery in Group 1 (P = 0.045). Group 2 patients had a significantly higher Therapeutic Intervention Scoring System score (P = 0.04) and required a significantly larger dose of fentanyl (P < 0.001). One patient in Group 2 required reintubation after a cerebrovascular accident. The overall mortality rate was 4% (2 patients in Group 2). There were no significant differences in any of the outcome variables. We conclude that immediate extubation can safely be performed after elective abdominal aortic aneurysm surgery. ⋯ In this prospective randomized study, we compared the outcome of patients undergoing elective aortic abdominal surgery who either were extubated immediately after surgery or after 4 h of stabilization in the intensive care unit. No significant differences were found in the length of intensive care unit or hospital stay, or 28-day mortality between the 2 groups.
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Anesthesia and analgesia · Dec 2001
Randomized Controlled Trial Comparative Study Clinical TrialSelective spinal anesthesia: a comparison of hyperbaric bupivacaine 4 mg versus 6 mg for outpatient knee arthroscopy.
A low-dose (4 mg), low-volume (0.8 mL), low-flow (2 min) technique with hyperbaric bupivacaine toward the dependent side oriented injection and maintenance of the lateral decubitus position for 10 min produced selective spinal anesthesia with rapid recession of motor block and early discharge home.
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Anesthesia and analgesia · Dec 2001
Randomized Controlled Trial Clinical TrialNeostigmine combined with bupivacaine, clonidine, and sufentanil for spinal labor analgesia.
We previously found that spinal clonidine prolongs labor analgesia when combined with spinal bupivacaine and sufentanil. We sought to determine whether the addition of spinal neostigmine to these drugs would further enhance labor analgesia. By use of a combined spinal/epidural technique, 36 patients were randomized to receive a hyperbaric spinal injection of bupivacaine 2.5 mg plus clonidine 50 microg and sufentanil 10 microg with or without neostigmine 10 microg. Pain, maternal hemodynamics, fetal heart rate, nausea, pruritus, sedation, motor block, sensory levels to pinprick, and maternal oxygen saturation were assessed at regularly specified intervals after spinal injection until additional analgesia was requested. The duration of spinal analgesia was similar between groups (215 +/- 60 min in the Control group versus 205 +/- 62 min in the Neostigmine group). Likewise, pain scores, the duration of labor, Apgar scores, and side effects were similar between groups except that patients administered neostigmine experienced significantly more nausea and vomiting (53% vs 7%, P = 0.01). We conclude that spinal neostigmine 10 microg produces severe nausea and does not potentiate the duration of spinal analgesia in laboring women from spinal bupivacaine, clonidine, and sufentanil. ⋯ Spinal neostigmine 10 microg as an adjunct to spinal bupivacaine, clonidine, and sufentanil produces severe nausea and fails to potentiate analgesia in laboring women.
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Anesthesia and analgesia · Dec 2001
Randomized Controlled Trial Clinical TrialEarly pregnancy does not reduce the C(50) of propofol for loss of consciousness.
Requirements for inhaled anesthetics decrease during pregnancy. There are no published data, however, regarding propofol requirements in these patients. Because propofol is often used for induction of general anesthesia when surgery is necessary in early pregnancy, we investigated whether early pregnancy reduces the requirement of propofol for loss of consciousness using a computer-assisted target-controlled infusion (TCI). Propofol was administered using TCI to provide stable concentrations and to allow equilibration between blood and effect-site (central compartment) concentrations. Randomly selected target concentrations of propofol (1.5-4.5 microg/mL) were administered to both pregnant women (n = 36) who were scheduled for pregnancy termination and nonpregnant women (n = 36) who were scheduled for elective orthopedic or otorhinolaryngologic surgery. The median gestation of the pregnant women was 8 wk (range, 6-12 wk). Venous blood samples for analysis of the serum propofol concentration were taken at 3 min and 8 min after equilibration of the propofol concentration. After a 10-min equilibration period of the predetermined propofol blood concentration, a verbal command to open their eyes was given to the patients twice, accompanied by rubbing of their shoulders. Serum propofol concentrations at which 50% of the patients did not respond to verbal commands (C(50) for loss of consciousness) were determined by logistic regression. There was no significant difference in C(50) +/- SE of propofol for loss of consciousness between the Nonpregnant (2.1 +/- 0.2 microg/mL) and Pregnant (2.0 +/- 0.2 microg/mL) groups. These results indicate that early pregnancy does not decrease the concentration of propofol required for loss of consciousness. ⋯ The C(50) of propofol for loss of consciousness in early pregnancy did not differ from that in nonpregnant women, indicating that there is no need to decrease the propofol concentration for loss of consciousness when inducing general anesthesia for termination of pregnancy.
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Anesthesia and analgesia · Dec 2001
Multicenter StudyPharmacokinetics of remifentanil in anesthetized pediatric patients undergoing elective surgery or diagnostic procedures.
Remifentanil hydrochloride is an ultra-short-acting opioid that undergoes rapid metabolism by tissue and plasma esterases. We aimed to characterize the pharmacokinetics and determine the hemodynamic profile of remifentanil after a single-bolus dose in children aged 0 to 18 yr. Forty-two children undergoing elective surgical procedures received remifentanil 5 microg/kg infused over 1 min. Patients were divided into age groups as follows: young infants (< or =2 mo), older infants (> 2 mo to < 2 yr), young children (2 to < 7 yr), older children (7 to < 13 yr), adolescents (13 to < 16 yr), and young adults (16 to < 18 yr). Arterial blood samples were collected and analyzed by mass spectroscopy to determine remifentanil pharmacokinetic profiles. Hemodynamic measurements for remifentanil's effect were made after the infusion. Methods of statistical analysis included analysis of variance and linear regression, with significance at P < or = 0.05. Complete remifentanil pharmacokinetic data were obtained from 34 patients. The volume of distribution was largest in the infants < 2 mo (mean, 452 mL/kg) and decreased to means of 223 to 308 mL/kg in the older patients. There was a more rapid clearance in the infants < 2 mo of age (90 mL. kg(-1). min(-1)) and infants 2 mo to 2 yr (92 mL. kg(-1). min(-1)) than in the other groups (means, 46 to 76 mL. kg(-1). min(-1)). The half-life was similar in all age groups, with means of 3.4 to 5.7 min. Seven subjects (17%) developed hypotension related to the remifentanil bolus. Remifentanil showed an extremely rapid elimination similar to that in adults. The fast clearance rates observed in neonates and infants, as well as the lack of age-related changes in half-life, are in sharp contrast to the pharmacokinetic profile of other opioids. Remifentanil in a bolus dose of 5 microg/kg may cause hypotension in anesthetized children. ⋯ The pharmacokinetics of remifentanil were studied in children from birth to 18 yr. Remifentanil was found to have age-related changes in clearance and volume of distribution, but not half-life. The increased clearance observed in young infants is in contrast to other opioids.