ISSN:0003-3022    

出版商:OVID    

年代:1997

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1997

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1997

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Background:Functional characteristics of the pharynx and upper esophagus, including aspiration episodes, were investigated in 14 awake volunteers during various levels of partial neuromuscular block. Pharyngeal function was evaluated using videoradiography and computerized pharyngeal manometry during contrast bolus swallowing.Methods:Measurements of pharyngeal constrictor muscle function (contraction amplitude, duration, and slope), upper esophageal sphincter muscle resting tone, muscle coordination, bolus transit time, and aspiration under fluoroscopic control (laryngeal or tracheal penetration) were made before (control measurements) and during a vecuronium‐induced partial neuromuscular paralysis, at fixed intervals of mechanical adductor pollicis muscle train‐of‐four (TOF) fade; that is, at TOF ratios of 0.60, 0.70, 0.80, and after recovery to a TOF ratio > 0.90.Results:Six volunteers aspirated (laryngeal penetration) at a TOF ratio < 0.90. None of them aspirated at a TOF ratio > 0.90 or during control recording. Pharyngeal constrictor muscle function was not affected at any level of paralysis. The upper esophageal sphincter resting tone was significantly reduced at TOF ratios of 0.60, 0.70, and 0.80 (P < 0.05). This was associated with reduced muscle coordination and shortened bolus transit time at a TOF ratio of 0.60.Conclusions:Vecuronium‐induced partial paralysis cause pharyngeal dysfunction and increased risk for aspiration at mechanical adductor pollicis TOF ratios < 0.90. Pharyngeal function is not normalized until an adductor pollicis TOF ratio of > 0.90 is reached. The upper esophageal sphincter muscle is more sensitive to vecuronium than is the pharyngeal constrictor muscle.

ISSN:0003-3022    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Background:Anesthetic drug expenditures have been a focus of cost‐containment efforts. The aim of this study was to determine whether expenditures for neuromuscular‐blocking agents could be reduced without compromising outcome, and to determine whether such a cost‐effective pattern of neuromuscular blocker use could be sustained.Methods:Education, practice guidelines, and paperwork barriers were used to persuade anesthesiologists to substitute low‐cost neuromuscular‐blocking drugs (pancuronium or a metocurine‐pancuronium combination) for a more costly neuromuscular‐blocking drug (vecuronium). Neuromuscular‐blocking drug use in all patients during a historical control period (6 months; n = 4,804) was compared with that during two consecutive 1‐yr periods of intervention (n = 9,761/n = 10,695). Expenditures for vecuronium and for all neuromuscular‐blocking drugs were compared for the control and intervention periods. The rate of complications related to neuromuscular‐blocking drugs was determined by an ongoing continuous quality improvement program.Results:Vecuronium use decreased by 76% during the first and second yr of intervention, compared with the historical period (P <0.01). The cost of neuromuscular‐blocking drugs decreased by 31% (P <0.01) and 47% (P < 0.01) for the first and second yr, respectively. The complication rate related to neuromuscular‐blocking drugs was 0.081% in the historical period and 0.11% and 0.093% during the intervention periods (P = 0.29 and 0.41).Conclusion:Practice guidelines, education, and paperwork barriers used together substantially reduced the expenditures for neuromuscular‐blocking drugs for 2 yr without adversely affecting clinical outcome.

ISSN:0003-3022    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Background:Redistribution of body heat decreases core temperature more during general than regional anesthesia. However, the combination of anesthetic‐ and sedative‐induced inhibition may prevent effective upper‐body thermoregulatory responses even during regional anesthesia. The extent to which each type of anesthesia promotes hypothermia thus remains controversial. Accordingly, the authors evaluated intraoperative core hypothermia in patients assigned to receive spinal or general anesthesia. They also tested the hypothesis that the efficacy of active postoperative warming is augmented when spinal anesthesia maintains vasodilation.Methods:Patients undergoing lower abdominal and leg surgery were randomly assigned to receive general anesthesia (isoflurane and nitrous oxide; n = 20) or spinal anesthesia (bupivacaine; n = 20). Fluids were warmed to 37 [degree sign] Celsius and patients were covered with surgical drapes. However, no other active warming was applied during operation. Ambient temperatures were maintained near 20 [degree sign] Celsius. After operation, patients were warmed with a full‐length, forced‐air cover set to 43 [degree sign] Celsius. Shivering, when observed, was treated with intravenous meperidine.Results:The mean spinal analgesia level, which was at the sixth thoracic level during surgery, remained at the T12 dermatome after 90 min after operation. Core temperatures did not differ significantly during surgery and decreased to 34.4 +/‐ 0.5 [degree sign] Celsius and 34.1 +/‐ 0.4 [degree sign] Celsius, respectively, in patients given spinal and general anesthesia. After operation, however, core temperatures increased significantly faster (1.2 +/‐ 0.1 [degree sign] Celsius/h vs. 0.7 +/‐ 0.2 [degree sign] Celsius/h, mean +/‐ SD; P <0.001) in patients given spinal anesthesia. Consequently, patients given spinal anesthesia required less time to rewarm to 36.5 [degree sign] Celsius (122 +/‐ 28 min vs. 199 +/‐ 28 min; P < 0.001).Conclusions:Comparable intraoperative hypothermia during general and regional anesthesia presumably resulted because the combination of spinal anesthesia and meperidine administration obliterated effective peripheral and central thermoregulatory control. Vasodilation increased the rate of core rewarming in patients after operation with residual lower‐body sympathetic blocks, suggesting that vasoconstriction decreased peripheral‐to‐core heat transfer after general anesthesia.

ISSN:0003-3022    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Background:During anesthesia in humans, anterior displacement of the mandible is often helpful to relieve airway obstruction. However, it appears to be less useful in obese patients. The authors tested the possibility that obesity limits the effectiveness of the maneuver.Methods:Total muscle paralysis was induced under general anesthesia in a group of obese persons (n = 9; body mass index, 32 +/‐ 3 kg sup ‐2) and in a group of nonobese persons (n = 9; body mas index, 21 +/‐ 2 kg sup ‐2). Nocturnal oximetry confirmed that none of them had sleep‐disordered breathing. The cross‐sectional area of the pharynx was measured endoscopically at different static airway pressures. A static pressure‐area plot allowed assessment of the mechanical properties of the pharynx. The influence of mandibular advancement on airway patency was assessed by comparing the static pressure‐area relation with and without the maneuver in obese and nonobese persons.Results:Mandibular advancement increased the retroglossal area at a given pharyngeal pressure, and mandibular advancement increased the retropalatal area in nonobese but not in obese persons at a given pharyngeal pressure.Conclusion:Mandibular advancement did not improve the retropalatal airway in obese persons.

ISSN:0003-3022    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Background:Microemboli occur commonly during cardiac surgery in adults, and, when present, increase the risk of neuropsychological deficits. Their incidence and significance during correction of congenital heart disease is unknown. The authors hypothesized that microemboli would occur before bypass with right‐to‐left cardiac shunts and would also occur in large numbers when the aortic crossclamp was released in children during repair of congenital heart defects.Methods:In 25 children studied with carotid artery Doppler, embolic signals were counted and timed in relation to 13 intraoperative events. Patients were classified as either at high risk (obligate right‐to‐left shunt or uncorrected transposition of the great arteries) or at low risk (net left‐to‐right shunt or simple obstructive lesions) for paradoxical (venous to arterial) emboli.Results:The median number of emboli detected was 122 (range, 2–2,664). Forty‐two percent of all emboli were detected within 3 min of release of the aortic crossclamp. The high‐risk group had significantly more emboli (median, 66; range, 0–116) during the time interval before cardiopulmonary bypass than did the low‐risk group (median, 8; range, 0–73), with P < 0.01. There was no significant difference between the high‐and low‐risk groups in the total number of emboli detected. There was no apparent association between number of emboli and gross neurologic deficits.Conclusions:Microemboli can be detected in the carotid arteries of children undergoing repair of congenital heart disease and are especially prevalent immediately after release of the aortic crossclamp. The role of emboli in causing neurologic injury in children undergoing repair of congenital heart disease remains to be determined.

ISSN:0003-3022    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Introduction:Opioid‐induced rigidity often makes bag‐mask ventilation difficult or impossible during induction of anesthesia. Difficult ventilation may result from chest wall rigidity, upper airway closure, or both. This study further defines the contribution of vocal cord closure to this phenomenon.Methods:With institutional review board approval, 30 patients undergoing elective cardiac surgery participated in the study. Morphine (0.1 mg/kg) and scopolamine (6 micro gram/kg) given intramuscularly provided sedation along with intravenous midazolam as needed. Lidocaine 10% spray provided topical anesthesia of the oropharynx. A fiberoptic bronchoscope positioned in the airway photographed the glottis before induction of anesthesia. A second photograph was obtained after induction with 3 micro gram/kg sufentanil administered during a period of 2 min. A mechanical ventilator provided 10 ml/kg breaths at 10/min via mask and oral airway with jaw thrust. A side‐stream spirometer captured objective pulmonary compliance data. Subjective airway compliance was scored. Pancuronium (0.1 mg/kg) provided muscle relaxation. One minute after the muscle relaxant was given, a third photograph was taken and compliance measurements and scores were repeated. Photographs were scored in a random, blinded manner by one investigator. Wilcoxon signed rank tests compared groups, with Bonferroni correction. Differences were considered significant at P <0.05.Results:Twenty‐eight of 30 patients exhibited decreased pulmonary compliance and closed vocal cords after opioid induction. Two patients with neither objective nor subjective changes in pulmonary compliance had open vocal cords after opioid administration. Both subjective and objective compliances increased from severely compromised values after narcotic‐induced anesthesia to normal values (P = 0.000002) after patients received a relaxant. Photo scores document open cords before induction, progressing to closed cords after the opioid (P = 0.00002), and opening again after a relaxant was administered (P = 0.00005).Conclusion:Closure of vocal cords is the major cause of difficult ventilation after opioid‐induced anesthesia.

ISSN:0003-3022    

出版商:OVID    

年代:1997

数据来源: OVID