ISSN:0003-3022    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

BackgroundMotor neuropathy of a lower extremity is well-recognized as a potential complication of procedures performed on patients in a lithotomy position. Most of this awareness is based on anecdotal reports, however, and the incidence and risk factors for this complication have not been reported.MethodsWe retrospectively reviewed the perioperative courses of 198,461 consecutive patients who underwent 1 of 56 surgical procedures historically performed on patients in a lithotomy position at the Mayo Clinic, Rochester, Minnesota, from 1957 to 1991 Inclusive. The medical diagnoses of patients who had procedures in a lithotomy position were scanned for 26 diagnoses associated with neuropathy. Persistent neuropathy of the lower extremity was denned as a motor deficit of at least 3 months' duration. Risk factors anecdotally associated with persistent neuropathy were analyzed by comparing identified cases of neuropathy to controls in a 1:3 case-control study.ResultsPersistent neuropathies after procedures performed on patients in a lithotomy position were identified in 55 cases for a rate of 1 per 3,608. Multivariate risk factors for development of a persistent neuropathy of a lower extremity Included duration In lithotomy of 4 h or longer, a body mass index (kilograms per squared meter) of 20 or less, and a history of smoking within 30 days of the procedure. Regional anesthetic techniques were not found to be associated with an increased risk of neuropathy. Of the 53 patients who lived at least 1 yr after their procedure, 24 (45%) required either prosthetic or ambulatory support for persistent foot drop or leg weakness.ConclusionsThese data suggest that prolonged duration in lithotomy and patient risk factors, including very thin body habitus and smoking in the preoperative period, are associated with the development of a lower-extremity neuropathy after procedures performed on patients In a lithotomy position. A reduction of time in the lithotomy position may be particularly worthwhile for patients with these risk factors.

ISSN:0003-3022    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

BackgroundWith rapid technological advances In anesthesiology, we are acquiring an ever increasing number of auditory alarm systems in the operating room the value of which depend on the hearing acuity of the anesthesiologist monitoring the patient. Presbycusis, the effect of aging on the auditory system, characteristically results in a bilaterally symmetric neurosensory high-frequency hearing loss (> 2,000 Hz). In this study we attempt to assess the impact of this common hearing disorder on alarm detection.MethodsWe measured air conduction hearing acuities of 188 anesthesiologists who volunteered to participate. Subjects were divided into six age groups (25–34, 35–44, 45–54, 55–64, and > 75 yr of age). Abnormal audiograms were compared to the intensity and frequency of alarms in our operating room to determine which alarms were out of hearing range. Subjects with a history of chronic or excessive noise exposure were excluded from the study. The median hearing threshold for each age group of study subjects was compared to the median hearing threshold of similar age groups in the general population.ResultsOverall, 66% of the subjects had an abnormal audiogram, and 7% had one or more alarm intensities less than their detectability threshold (14% unilateral, 86% bilateral). Median hearing threshold was worse than the general population for men and women less than 55 yr of age. Hearing acuity worse than the general population occurred at the lower frequencies while acuity at the higher frequencies was equal or slightly better. However, inability to hear alarms occurred only with those alarms that have frequencies of 4,000 Hz or greater.ConclusionsAlthough high-frequency hearing acuity of individuals In our study was better than that of the general population, hearing deficits at high frequencies were of the magnitude to interfere with alarm detection. Also background noise levels vary greatly in different operating rooms. These two problems create a hindrance to alarm detection for certain anesthesiologists. From our data we conclude that the aging human ear may not be capable of accurately detecting some auditory alarms in the operating room. Alarm design should consider hearing acuity because high-frequency alarms may go undetected.

ISSN:0003-3022    

出版商:OVID    

年代:1994

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

BackgroundBack pain after childbirth is a frequent complaint. The purpose of this study was to determine the incidence of back pain 1–2 months post partum and to identify the factors, including epidural anesthesia for labor and delivery, that may predispose to it.MethodsWomen delivering a viable singleton infant were interviewed 12–48 h after delivery for a history of back pain that occurred before, during, or both before and during the recent pregnancy and for details of their delivery experience. Two months later, the women interviewed were sent a follow-up questionnaire regarding the occurrence of back pain 1–2 months post partum.ResultsFollow-up data were available for 1,042 (88%) of the 1,185 women originally interviewed. The Incidence of post partum back pain in women who received epidural anesthesia was equivalent to those who did not (44% vs. 45%). Through stepwise multiple logistic regression, post partum back pain was found to be associated with a history of back pain, younger age, and greater weight. However, new-onset post partum back pain was found to be associated with greater weight and shorter stature. No statistically significant association was found between post partum back pain and epidural anesthesia, number of attempts at epidural placement, duration of second stage of labor, mode of delivery, or birth weight.ConclusionsThe overall incidence of back pain 1–2 months post partum in this population was 44%. Predisposing factors were a history of back pain, younger age, and greater weight. Predisposing factors for new-onset post partum back pain were greater weight and shorter stature. Epidural anesthesia for labor and delivery did not appear to be associated with back pain 1–2 months post partum.

ISSN:0003-3022    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

BackgroundThe optimal site for monitoring neuromuscular blockade for Intubations facilitated with mivacurium chloride has not been established. The primary purpose of this evaluation was to determine the difference in onset of neuromuscular blockade between the orbicularis oculi and adductor pollicis in patients administered mivacurium chloride. We also evaluated Intubatlng conditions when intubation was timed to maximal neuromuscular blockade at either the orbicularis oculi or the adductor pollicis. The results for patients administered mivacurium chloride were compared with those for a control group administered succinylcholine.MethodsIn a double-blind randomized design, the time to loss of the compound muscle action potential at the orbicularis oculi and adductor pollicis was monitored in 20 patients administered mivacurium chloride and ten patients administered succinylcholine. After administration of mivacurium chloride (0.15 mg·kg-1), ten patients underwent tracheal intubation at maximal depression of the orbicularis oculi (group 2) and ten patients at maximal depression of the adductor pollicis (group 3). In an additional ten patients the trachea was intubated 60 s after administration of succinylcholine (1 mg·kg-1) (group 1, control). Intubation and evaluation of conditions was performed by one Investigator blinded to patient treatments.ResultsLoss of compound muscle action potential at the orbicularis oculi and adductor pollicis was more rapid in group 1, and Intubation was completed at 86 ± 26 s. In the patients administered mivacurium chloride, the orbicularis oculi compound muscle action potential was lost 3 min earlier than the adductor pollicis compound muscle action potential. Subsequently, Intubation was completed at 134 ± 50 s in the orbicularis oculi group, whereas the time to intubation was 321 ± 57 s in the adductor pollicis group. There was no significant differences in intubation conditions between the mivacurium chloride groups.ConclusionsWhen monitoring 95% twitch height depression of the orbicularis oculi muscle, intubation can be accomplished in approximately 2 min after administration of mivacurium chloride (0.15 mg·kg-1). Because Intubating conditions were comparable to the patients administered succinylcholine or intubated during monitoring of the twitch height depression of the adductor pollicis, we believe that optimal site for monitoring during intubation using mivacurium chloride is the orbicularis oculi muscle.

ISSN:0003-3022    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

BackgroundAfter Induction of anesthesia, lung resistance increases. We hypothesized that prophylactic bronchodilator treatment before tracheal intubation would result in a lower lung resistance after placement of the endotracheal tube.MethodsForty-two adult patients were randomized to receive one of three inhaled medications 1 h before surgery. All patients first underwent pulmonary function tests. Patients then received either inhaled albuterol (360 μg) (n = 12), Inhaled ipratroplum bromide (72 μg) (n = 15) or a placebo Inhalation (n = 15). Two, 5, and 15 min after tracheal intubation, lung resistance was measured using the method of von Neergard and Wirtz.ResultsPatients who received either bronchodilator had significantly lower lung resistance after intubation than those receiving placebo. At 2 min, lung resistances were 12.7 ± 1.4 cmH2O·1-1·s-1(mean ± SEM) for the placebo group, 6.4 ± 3.1 cmH2O·1-1·s-1for the ipratropium-treated group (P < 0.05 vs. placebo), and 7.2 + 0.8 cmH2O·1-1·s-1for the albuterol-treated group (P < 0.05 vs. placebo). The differences in lung resistance persisted through the final measurement at 15 min. Three of fifteen placebo-treated patients developed audible wheezing whereas no patients developed wheezing In either bronchodilator-treated group (P < 0.05 by Fisher's exact test). Although smokers and nonsmokers in the placebo group developed similar resistances after intubation, bronchodilator treatment resulted in lower resistance in nonsmokers than in smokers (P < 0.05).ConclusionsProphylactic treatment with either an inhaled β2-adrenergic agonist or an inhaled cholinergic antagonist produced lower lung resistance after intubation when compared with an inhaled placebo medication. The effect was more pronounced in nonsmokers than in smokers.

ISSN:0003-3022    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

BackgroundLeft ventricular diastolic function Is known to be impaired in patients with coronary artery disease and patients with valvular aortic stenosis. Phenylephrine is frequently administered as an Intravenous bolus in these patients perioperatively to increase coronary perfusion pressure. Although this is common practice, there is no information about the effect of phenylephrine bolus administration on left ventricular filling dynamics.MethodsTwenty patients with coronary artery disease (group 1), 15 patients with valvular aortic stenosis (group 2), and 10 subjects without cardiovascular disease (group 3, control) entered the study. Left ventricular filling was evaluated using transesophageal pulsed Doppler echocardiography before and after phenylephrine Injection given to patients whose mean blood pressure has decreased by more than 20% (and was not higher than 90 mmHg). We recorded the transmitral blood flow velocity curve and measured peak early and peak atrial flow velocity, acceleration and deceleration time of the early flow velocity peak, and mitral valve diameter. We calculated the ratio of peak early to peak atrial flow velocity (PE/PA), acceleration and deceleration rate of the early flow peak, and peak filling rate.ResultsPhenylephrine effectively restored arterial pressure in all three groups. However, in group 1, phenylephrine administration resulted in a reduction of PE/PA, acceleration rate of the early flow peak, and peak filling rate from 1.25 (mean) to 0.75 (P < 0.001), 411 to 276 cm/s2(P < 0.001), and 439 to 305 ml/s (P < 0.001), respectively. In contrast, in group 2, intravenous phenylephrine Increased PE/PA, acceleration rate of the early flow peak, and peak filling rate from 0.76 to 0.97 (P < 0.001), 365 to 503 cm/s2(P < 0.05), and 321 to 388 ml/s (P < 0.01), respectively. In the control subjects, phenylephrine caused a transient reduction of PE/PA and peak filling rate from 1.71 to 1.39 (P <0.001) and 618 to 524 ml·s-1(P < 0.001), respectively.ConclusionsPhenylephrine bolus administration causes an alteration of left ventricular filling In coronary artery disease patients that seems to be more marked than that seen In normal subjects. In patients with aortic stenosis no deleterious effects were observed in response to phenylephrine.

ISSN:0003-3022    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

BackgroundCumulative effects (Increased 25–75% recovery time with increasing dose) are evident with vecuronium but not with atracurium. Pharmacokinetic simulations suggest that vecuronium's cumulation occurs as recovery shifts from distribution to elimination whereas atracurium's recovery always occurs during elimination. The purpose of this study was to examine this pharmacokinetic explanation.MethodsWe assigned 12 volunteers to receive atracurium or vecuronium on three occasions during nitrous oxide-isoflurane anesthesia. Evoked adductor pollicis twitch tension was monitored. On occasion 1, the dose expected to produce 95% block (ED95) was estimated for each subject. On occasions 2 and 3, 1.2 or 3.0 multiples of ED95were given as a bolus. Plasma was sampled for 128 min to determine muscle relaxant concentrations; pharmacodynamic modeling was used to determine effect-compartment drug concentrations (Ce). For each drug, recovery time, recovery phase half-life (rate of decrease in Ce during recovery), and Ce at 25% and 75% recovery were compared between doses.ResultsAtracurium's recovery time increased 2.4 ± 2.2 min (mean ± SD) with the larger dose, less than the Increase with vecuronium (8.2 ± 3.8 min). Atracurium's recovery phase half-life was 14.6 ± 1.7 and 20.1 ± 2.3 min with the small and large doses (P < 0.05); vecuronium's recovery phase half-life increased similarly from 13.5 ± 2.3 to 18.5 ± 5.0 min (P < 0.05). At 75% recovery, vecuronium's Ce decreased from 65 ± 18 ng/ml with the small dose to 55 ± 15 ng/ml with the large dose (P < 0.05). Assuming that neuromuscular junction sensitivity was constant, this difference could be explained by considering neuromuscular effects of vecuronium's metabolite, 3-desacetylvecuronium.ConclusionsAlthough vecuronium was cumulative (as predicted), atracurium was also slightly cumulative. Inconsistent with our hypothesis, recovery phase half-lives for both drugs Increased similarly between doses; therefore, differences In cumulation were not solely explained by pharmacokinetics of the muscle relaxant. It appears that 3-desacetyIvecuronium contributes to vecuronium's cumulative effect, even after usual clinical doses.

ISSN:0003-3022    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

BackgroundPrevious studies have suggested that the degree of visibility of oropharyngeal structures (OP class) and nun-dibular space (MS) length can predict difficult laryngoscopy. However, those studies were either inconsistent or omit description of how to perform these tests with regard to body, head and tongue position, and the use of phonation, hyoid versus thyroid cartilage and inside versus outside of the mentum. The purpose of this investigation was to determine which method of testing best predicts difficult laryngoscopy.MethodsIn each of 213 consenting adults the OP class was determined in 24 method combinations: two body positions (sitting and supine), three head positions (neutral, sniff, and full extension), two tongue positions (in and out), and with and without phonation. In each patient MS length was measured in 24 method combinations: two body positions (sitting and supine), three head positions (neutral, sniff, and full extension), two distal end points (hyoid and thyroid cartilage), and two proximal end points (Inside and outside of the men-turn). In each patient the laryngoscopic grade was determined at the time of induction of anesthesia. We denned laryngoscopic grades III (n = 24) and 4 (n = 0) as difficult. The area under the receiver operating characteristic curve (ROC area) for each combination was used to compare the combinations and determine significant differences: ROC area = 0.5 implied a totally uninformative combination and ROC area = 1.0 a combination that predicted perfectly. Logistic regression analysis was used to calculate a predictor of difficult intubation that combined both OP class and MS length (the performance index). The performance index could then be used to calculate sensitivity, specificity, positive and negative predictive value, and probability of difficult intubation.ResultsThe ROC areas for the different combinations used to assess OP class ranged from 0.78 to 0.94. The best combination was with the patient sitting, head in extension, tongue out, and with or without phonation. For MS length, the ROC areas ranged from 0.58 to 0.77; the best combination was the patient sitting, with the head in extension, with distance measured from the inside of the mentum to the thyroid cartilage. Combining the OP class and MS length (Performance Index = 2.5 × OP class – MS length in centimeters) significantly increased predictability of difficult intubation. At performance Index = 0 and = 2, the probability of difficult intubation was 3.5% and 24%, respectively. With clinically relevant outpoints for the performance index it was found that most difficult intubations could be predicted, but approximately half of those predicted to be difficult would in fact be easy.ConclusionsBased on the above ROC areas and ease of performing the test for the patient, we recommend that these tests be performed with patients in the sitting position, with the head in full extension, the tongue out, and with phonation, and with distance measured from the thyroid cartilage to inside of the mentum. Nevertheless, it is clear that these two tests, either used alone or in combination, will fail to predict a few difficult laryngoscopies and that they will predict difficult laryngoscopy in a significant number of patients in whom the trachea is easy to intubate.

ISSN:0003-3022    

出版商:OVID    

年代:1994

数据来源: OVID