Anesthesia and analgesia
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Anesthesia and analgesia · Sep 1998
Randomized Controlled Trial Comparative Study Clinical TrialIntrathecal ropivacaine for labor analgesia: a comparison with bupivacaine.
Ropivacaine has less potential for central nervous system and cardiovascular toxicity than bupivacaine; in pregnant patients and volunteers, it produces less motor block in equianalgesic doses than bupivacaine. We compared two doses of intrathecal ropivacaine combined with sufentanil with a standard dose of intrathecal bupivacaine plus sufentanil for labor analgesia using a combined spinal-epidural (CSE) technique. In a prospective, randomized, double-blind fashion, 48 patients requesting labor analgesia received either 2.5 mg of intrathecal bupivacaine plus sufentanil 10 microg (B), 2 mg of intrathecal ropivacaine plus sufentanil 10 microg (R2), or 4 mg of intrathecal ropivacaine plus sufentanil 10 microg (R4). Duration of analgesia and side effects, such as motor block, pruritus, hypotension, ephedrine requirements and fetal bradycardia, were recorded. Duration of analgesia (mean +/- SD) was 79+/-30 min for R2, 98+/-19 min for R4, and 92+/-38 min for B (P = not significant). No differences in motor block or side effects were detected among the groups. We conclude that ropivacaine, when combined with sufentanil, is effective for providing CSE labor analgesia and offers no advantage over bupivacaine in the studied doses. ⋯ In this study, we compared a standard dose of intrathecal bupivacaine with sufentanil for combined spinal epidural analgesia with two doses of the new local anesthetic ropivacaine. Both local anesthetics provided similar labor analgesia duration with equivalent side effect profiles in the doses studied.
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Anesthesia and analgesia · Sep 1998
Randomized Controlled Trial Clinical TrialEsmolol potentiates reduction of minimum alveolar isoflurane concentration by alfentanil.
Esmolol, a short-acting beta1-receptor antagonist, decreases anesthetic requirements during propofol/N2O/morphine anesthesia. This study was designed to determine whether esmolol affects the volatile anesthetic (isoflurane) required to prevent movement to skin incision in 50% patients (minimum alveolar anesthetic concentration [MAC]) with or without an additional opioid (alfentanil). One hundred consenting adult patients were randomly divided into five treatment groups: isoflurane alone (I), I with continuous large-dose (250 microg x kg(-1) x min(-1)) esmolol (E), I with alfentanil (effect site target of 50 ng/mL) via a continuous computer-controlled infusion (A), A plus continuous small-dose (50 microg x kg(-1) x min(-1)) esmolol (A1), or A plus large-dose esmolol (A2). Anesthesia was induced via a face mask, and steady-state target end-tidal isoflurane concentrations were maintained before incision. The MAC of isoflurane alone was 1.28% +/- 0.13%. Large-dose esmolol did not significantly alter the isoflurane MAC (1.23% +/- 0.14%). Alfentanil alone significantly decreased isoflurane MAC by 25% (0.96% +/-0.09%). Adding small-dose esmolol did not further decrease MAC with alfentanil (0.96% +/- 0.13%). However, large-dose esmolol significantly decreased isoflurane MAC with alfentanil (0.74% +/- 0.09%). Esmolol and alfentanil both significantly reduced the increases in heart rate and mean arterial pressure associated with endotracheal intubation and incision. The mechanism of this effect is unknown. ⋯ Most anesthetic techniques rely on a balance of several highly selective medications. The current results define a new anesthetic-sparing effect when volatile anesthetic, analgesic, and beta-adrenergic blocking drugs are combined.
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Anesthesia and analgesia · Sep 1998
Clinical TrialThe effects of body mass on lung volumes, respiratory mechanics, and gas exchange during general anesthesia.
We investigated the effects of body mass index (BMI) on functional residual capacity (FRC), respiratory mechanics (compliance and resistance), gas exchange, and the inspiratory mechanical work done per liter of ventilation during general anesthesia. We used the esophageal balloon technique, together with rapid airway occlusion during constant inspiratory flow, to partition the mechanics of the respiratory system into its pulmonary and chest wall components. FRC was measured by using the helium dilution technique. We studied 24 consecutive and unselected patients during general anesthesia, before surgical intervention, in the supine position (8 normal subjects with a BMI < or = 25 kg/m2, 8 moderately obese patients with a BMI >25 kg/m2 and <40 kg/m2, and 8 morbidly obese patients with a BMI > or = 40 kg/m2). We found that, with increasing BMI: 1. FRC decreased exponentially (r = 0.86; P < 0.01) 2. the compliance of the total respiratory system and of the lung decreased exponentially (r = 0.86; P < 0.01 and r = 0.81; P < 0.01, respectively), whereas the compliance of the chest wall was only minimally affected (r = 0.45; P < 0.05) 3. the resistance of the total respiratory system and of the lung increased (r = 0.81; P < 0.01 and r = 0.84; P < 0.01, respectively), whereas the chest wall resistance was unaffected (r = 0.06; P = not significant) 4. the oxygenation index (PaO2/PAO2) decreased exponentially (r = 0.81; P < 0.01) and was correlated with FRC (r = 0.62; P < 0.01), whereas PaCO2 was unaffected (r = 0.06; P = not significant) 5. the work of breathing of the total respiratory system increased, mainly due to the lung component (r = 0.88; P < 0.01 and r = 0.81; P < 0.01, respectively). In conclusion, BMI is an important determinant of lung volumes, respiratory mechanics, and oxygenation during general anesthesia with patients in the supine position. ⋯ The aim of this study was to investigate the influence of body mass on lung volumes, respiratory mechanics, and gas exchange during general anesthesia.
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Anesthesia and analgesia · Sep 1998
Clinical TrialPredictive factors of outcome in severely traumatized children.
To identify risk factors associated with death in traumatized children, we prospectively studied 507 consecutive patients (7+/-4 yr) admitted to a level I pediatric trauma center over a 3-yr period. Pediatric Trauma Score (PTS), Glasgow Coma Scale (GCS) score, and Injury Severity Score (ISS) were calculated. Age, injury mechanism, injury pattern, and initial critical care were recorded. Univariate and multivariate analyses were performed for potential risk factors associated with mortality. Receiver operating characteristic curves were used to determine threshold values of variables identified by univariate analysis. Most children suffered from blunt trauma (99.6%), and head trauma was noted in 85%. Median values (range) of GCS scores, PTS, and ISS were 10 (3-15), 7 (-4 to 12), and 16 (3-75), respectively. The mortality rate was 12%. Using multivariate analysis, death was significantly associated with an ISS > or = 25 (odds ratio [OR] 22.2, 95% confidence interval 2.8-174.9), GCS score < or = 7 (OR 4.77, 1.8-12.7), emergency blood transfusion > or = 20 mL/kg (OR 4.3, 2.1-9.1), and PTS < or = 4 (OR 3.7, 1.4-9.7). An ISS > or = 25, GCS score < or = 7, immediate blood transfusion > or = 20 mL/kg, and PTS < or = 4 were significant and independent risk factors of death in an homogenous population of severely injured children. The probability of traumatic death was therefore 0 (95% confidence interval 0-0.0135) in children with no one of these threshold values in the four predictive factors and 0.63 (95% confidence interval 0.47-0.76) in those children with all the threshold values. ⋯ Methods used for evaluating outcome of trauma patients have essentially been derived from adult series, and attempts to apply them to children have usually been inaccurate. Univariate and multivariate analyses were performed to identify risk factors associated with death in severely traumatized children, and Receiver operating characteristic curves were used to determine threshold values.
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Anesthesia and analgesia · Sep 1998
Randomized Controlled Trial Clinical TrialWidespread application of topical steroids to decrease sore throat, hoarseness, and cough after tracheal intubation.