Anesthesia and analgesia
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Anesthesia and analgesia · Jul 2003
Clinical TrialARX-derived auditory evoked potential index and bispectral index during the induction of anesthesia with propofol and remifentanil.
A new commercial auditory evoked potential (AEP) monitor (A-line AEP monitor) was developed to calculate an index (ARX AEP index; AAI) by automatically using the amplitudes and latencies of the AEP. We investigated 30 patients before spine surgery. AAI; bispectral index (BIS); relative (%) delta, theta, alpha, and beta; spectral edge frequency; median frequency; mean arterial blood pressure; heart rate; and oxygen saturation were obtained simultaneously during stepwise (1.0 micro g/mL) induction of target-controlled propofol concentration until 5.0 micro g/mL, followed by an infusion of 0.3 micro g. kg(-1). min(-1) of remifentanil. Every minute, the patients were asked to squeeze the observer's hand. Prediction probability (Pk), receiver operating characteristic, and logistic regression were used to calculate the probability to predict the conditions AWAKE, UNCONSCIOUSNESS (first loss of hand squeeze), and steady-state ANESTHESIA (5.0 micro g/mL of propofol and 0.3 micro g. kg(-1). min(-1) of remifentanil). Although a statistically significant difference among the conditions was observed for AAI, BIS, mean arterial blood pressure, median frequency, and %alpha, only AAI and BIS were able to distinguish UNCONSCIOUSNESS versus AWAKE and ANESTHESIA versus AWAKE with better than Pk = 0.90. The modern electroencephalographic variables AAI and BIS were superior to the classic electroencephalographic and hemodynamic variables to distinguish the observed anesthetic conditions. ⋯ The modern electroencephalographic ARX-derived auditory evoked potential index and the bispectral index were superior to the classic electroencephalographic and hemodynamic variables for predicting anesthetic conditions. Variables derived from the auditory evoked potential did not provide an advantage over variables derived from spontaneous electroencephalogram.
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Anesthesia and analgesia · Jul 2003
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of dexamethasone, ondansetron, and dexamethasone plus ondansetron as prophylactic antiemetic and antipruritic therapy in patients receiving intrathecal morphine for major orthopedic surgery.
In a prospective, double-blinded, randomized trial, we evaluated the efficacy of IV (a) dexamethasone 8 mg, (b) ondansetron 8 mg, and (c) dexamethasone 8 mg plus ondansetron 4 mg for the prevention of postoperative nausea, vomiting (PONV), and pruritus in 130 (ASA physical status I to III) patients undergoing elective major orthopedic surgery after spinal anesthesia with hyperbaric 0.5% bupivacaine and intrathecal morphine. After spinal anesthesia, patients were randomized to one of three groups. Failure of PONV prophylaxis in the 24-h postoperative period occurred more frequently in patients who received dexamethasone alone (29 of 40; 73%) compared with those who received either ondansetron alone (23 of 47; 49%) (P = 0.02) or dexamethasone plus ondansetron together (19 of 43; 44%)(P = 0.01). There was no difference in the incidence of failure of prophylaxis of pruritus (70%, 72%, and 70% in dexamethasone 8 mg, ondansetron 8 mg, and dexamethasone 8 mg plus ondansetron 4 mg, respectively) (P > 0.1) in the 24-h postoperative period. We conclude that the administration of dexamethasone 8 mg with ondansetron 4 mg has no added benefit compared with ondansetron 8 mg alone in the prophylaxis of PONV and pruritus. ⋯ Postoperative nausea and vomiting (PONV) and pruritus are common side effects after spinal opioid administration. In this study, dexamethasone 8 mg plus ondansetron 4 mg was as effective as ondansetron 8 mg. The administration of dexamethasone alone was associated with a frequent incidence of PONV, demonstrating a lack of efficacy. This has important cost implications.
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Anesthesia and analgesia · Jul 2003
Randomized Controlled Trial Clinical TrialThe effects of common airway maneuvers on airway pressure and flow in children undergoing adenoidectomies.
Obstruction of the upper airway occurs frequently in anesthetized, spontaneously breathing children, especially in those with adenoidal hyperplasia. To improve airway patency, maneuvers such as chin lift (CL), jaw thrust (JT), and continuous positive airway pressure (CPAP) are often used. In this study, we examined the comparative efficacy of these maneuvers in children scheduled to undergo adenoidectomy. Sixteen children aged 2-9 yr were anesthetized with sevoflurane. During spontaneous breathing, the flows and pressures in the mask (ma), oropharynx (op), and esophagus (es) were measured simultaneously, and maximal pressure differences during inspiration (DeltaP) were calculated. After baseline recording, CL and JT maneuvers were performed in random order without and with CPAP (5 cm H(2)O). The observed DeltaP(ma) - P(es) of 12.3 +/- 3.4 cm H(2)O at baseline decreased with all airway maneuvers (P < 0.05). This resulted from decreases of DeltaP(ma) - P(op) (P < 0.05) and DeltaP(op) - P(es) (P < 0.05) in all interventions except CL, in which DeltaP(ma) - P(op) remained similar. In contrast, significant improvements of minute ventilation and maximal inspiratory peak flow (P > 0.05) were observed only with JT (with and without CPAP). We conclude that CL may improve airway patency and ventilation, whereas JT with or without CPAP was the most effective maneuver to overcome airway obstruction in children with adenoidal hyperplasia. ⋯ Airway maneuvers are often used in anesthetized children to relieve airway obstruction during spontaneous ventilation. Compared with chin lift and continuous positive airway pressure, the jaw thrust maneuver was the most effective to improve airway patency and ventilation in children undergoing adenoidectomy.
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Anesthesia and analgesia · Jul 2003
Randomized Controlled Trial Clinical TrialThe preventive effects of mupirocin against nasotracheal intubation-related bacterial carriage.
Nasotracheal intubation is often required during dental and maxillofacial surgery. The complications of nasotracheal intubation are well documented, but there have been few systematic attempts to find methods for their prevention. We examined intubation-related carriage of bacteria, especially methicillin-resistant Staphylococcus aureus (MRSA), into the trachea and evaluated the effects of topical nasal treatment with mupirocin on intubation-related bacterial colonization. Of 38 patients without mupirocin treatment (nontreatment group), 27 (71.1%) showed general bacterial colonization in the nasal cavities before intubation. MRSA was isolated from 13.2% of the patients in this group. However, 10 of 22 patients (45%) treated with mupirocin (treatment group) showed colonization by general bacteria, and 2 (9%) were MRSA carriers before intubation. After nasal intubation, general bacteria and MRSA were isolated from the endotracheal tube tip in 66.2% and 16.7% of these patients in the nontreatment group, respectively. In contrast, general bacteria were isolated from the endotracheal tube tip in 19.2% of these patients after oral intubation, but no MRSA was detected. However, after nasal intubation, general bacteria were isolated from the endotracheal tube tip in 3 of the patients in the treatment group (23.1%), and no MRSA was detected, whereas no bacteria were isolated from oral intubation tubes. These results indicate that bacteria were carried into the trachea at a more frequent rate by nasal intubation as compared with oral intubation, and nasal treatment with mupirocin eliminated the nasal carriage of S. aureus. Topical nasal treatment with mupirocin before nasal intubation is thus suggested to be effective for preventing carriage of bacteria into the trachea. ⋯ We studied the carriage rate of bacteria into the trachea caused by nasal intubation. The bacterial carriage by nasal intubation was more frequent than that by oral intubation, and intranasal administration of mupirocin eliminated the carriage of S. aureus. These results indicate that topical nasal treatment with mupirocin is effective to prevent carriage of bacteria into the trachea.
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Anesthesia and analgesia · Jul 2003
Comparative Study Clinical TrialTarget-controlled infusion of rocuronium in infants, children, and adults: a comparison of the pharmacokinetic and pharmacodynamic relationship.
Target-controlled infusion (TCI) of rocuronium can be used to maintain a stable blood concentration (Cp). At steady-state, the pharmacokinetics (PK) are compensated for by TCI, and a stable effect can be observed. The theoretical Cp may represent effect-site concentration (EC). We used the EC-effect relationship to study pharmacodynamics (PD) in infants, children, and adults. After giving their written, informed consent, 14 infants, 23 children, and 21 adults scheduled for elective surgical procedures received 3 to 6 ascending Cp targets of TCI rocuronium according to PD data. Just before each increase of TCI, venous blood samples were taken to measure Cp. Neuromuscular block was evaluated acceleromyographically. Individual effect data and measured Cp were fitted to the Hill equation. Maximum block during TCI targets-1000, 1300, and 1600 ng/mL-was smaller in children in comparison with infants and adults. The concentration in the effect compartment associated with a 50% drug effect (EC(50)) was significantly smaller in infants (mean [SD]) (652 [215] ng/mL) than in adults (954 [276] ng/mL) and was the largest in children (1200 [295] ng/mL). Calculated mean EC(90) values were 1705, 2230, and 2035 ng/mL, respectively, in infants, children, and adults. TCI rocuronium established steady-state PK/PD at different TCI targets and allowed us to define PK/PD relationships in a standardized way. Steady-state TCI rocuronium revealed the most potency of rocuronium in infants and the least in children. ⋯ Target-controlled infusion (TCI) of rocuronium in infants, children, and adults was used to analyze the pharmacokinetic/pharmacodynamic relationship. Steady-state TCI rocuronium revealed the most potency of rocuronium in infants and the least in children.