ISSN:0003-3022    

出版商:OVID    

年代:2000

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:2000

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:2000

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:2000

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

BackgroundMaintenance of airway patency and oxygenation are the main objectives of face-mask ventilation. Because the incidence of difficult mask ventilation (DMV) and the factors associated with it are not well known, we undertook this prospective study.MethodsDifficult mask ventilation was defined as the inability of an unassisted anesthesiologist to maintain the measured oxygen saturation as measured by pulse oximetry > 92% or to prevent or reverse signs of inadequate ventilation during positive-pressure mask ventilation under general anesthesia. A univariate analysis was performed to identify potential factors predicting DMV, followed by a multivariate analysis, and odds ratio and 95% confidence interval were calculated.ResultsA total of 1,502 patients were prospectively included. DMV was reported in 75 patients (5%; 95% confidence interval, 3.9–6.1%), with one case of impossible ventilation. DMV was anticipated by the anesthesiologist in only 13 patients (17% of the DMV cases). Body mass index, age, macroglossia, beard, lack of teeth, history of snoring, increased Mallampati grade, and lower thyromental distance were identified in the univariate analysis as potential DMV risk factors. Using a multivariate analysis, five criteria were recognized as independent factors for a DMV (age older than 55 yr, body mass index > 26 kg/m2, beard, lack of teeth, history of snoring), the presence of two indicating high likelihood of DMV (sensitivity, 0.72; specificity, 0.73).ConclusionIn a general adult population, DMV was reported in 5% of the patients. A simple DMV risk score was established. Being able to more accurately predict DMV may improve the safety of airway management.

ISSN:0003-3022    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

BackgroundThe authors compared airway management in normogravity and simulated microgravity with and without restraints for laryngoscope-guided tracheal intubation, the cuffed oropharyngeal airway, the standard laryngeal mask airway, and the intubating laryngeal mask airway.MethodsFour trained anesthesiologist–divers participated in the study. Simulated microgravity during spaceflight was obtained using a submerged, full-scale model of the International Space Station Life Support Module and neutrally buoyant equipment and personnel. Customized, full-torso manikins were used for performing airway management. Each anesthesiologist–diver attempted airway management on 10 occasions with each device in three experimental conditions: (1) with the manikin at the poolside (poolside); (2) with the submerged manikin floating free (free-floating); and (3) with the submerged manikin fixed to the floor using a restraint (restrained). Airway management failure was defined as failed insertion after three attempts or inadequate device placement after insertion.ResultsFor the laryngoscope-guided tracheal intubation, airway management failure occurred more frequently in the free-floating (85%) condition than the restrained (8%) and poolside (0%) conditions (both,P< 0.001). Airway management failure was similar among conditions for the cuffed oropharyngeal airway (poolside, 10%; free-floating, 15%; restrained, 15%), laryngeal mask airway (poolside, 0%; free-floating, 3%; restrained, 0%), and intubating laryngeal mask airway (poolside, 5%; free-floating, 5%; restrained, 10%). Airway management failure for the laryngoscope-guided tracheal intubation was usually caused by failed insertion (> 90%), and for the cuffed oropharyngeal airway, laryngeal mask airway, and intubating laryngeal mask airway, it was always a result of inadequate placement.ConclusionThe emphasis placed on the use of restraints for conventional tracheal intubation in microgravity is appropriate. Extratracheal airway devices may be useful when restraints cannot be applied or intubation is difficult.

ISSN:0003-3022    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

BackgroundThrombelastograph®analysis (TEG®) is used to evaluate blood coagulation. Ideally, whole blood is immediately processed. If impossible, blood may be citrated and assessed after recalcification. No data describe the effect of such treatment and storage on TEG®parameters.MethodsThree studies were performed in 90 surgical patients. In 30 patients, blood was citrated (1:10, 0.129 M) and recalcified (20 &mgr;l 2 M CaCl2to 340 &mgr;l citrated blood), and TEG®was performed with native blood and after recalcification after 0, 15, and 30 min of citrate storage. In another 30 patients, TEG®was performed with citrated blood recalcified immediately and after 1–72 h storage. In a third study, thrombin–antithrombin complex, prothrombin fragment 1+2, and &bgr;-thromboglobulin were measured (using enzyme-linked immunoabsorbant assay tests) at corresponding time points. Data were compared using repeated-measures analysis of variance andpost hocpairedttests.ResultsTEG®parameters were different in recalcified citrated blood compared with native blood (P< 0.05) and changed significantly during 30-min (P< 0.025) and 72-h (P< 0.001) citrate storage. TEG®parameters measured between 1 and 8 h of citrate storage were stable. Thrombin–antithrombin complex and prothrombin fragment 1+2 values were not elevated in native blood. After 30 min of citrate storage a gradual thrombin activation was observed, as evidenced by increasing thrombin–antithrombin complex and prothrombin fragment 1+2 values (P< 0.05). &bgr;-Thromboglobulin level was increased after 2 and 8 h of citrate storage (P< 0.01).ConclusionsAnalysis of native blood yields the most reliable TEG®results. Should immediate TEG®processing not be possible, citrated blood may be used if recalcified after 1–8 h.

ISSN:0003-3022    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

BackgroundPreoperative acute normovolemic hemodilution may compromise oxygen transport. The aims of our study were to describe the hemodynamic effects of normovolemic hemodilution and to determine its effect on systolic and diastolic cardiac function by multiplane transesophageal echocardiography.MethodsIn eight anesthetized patients (aged 13–51 yr) without heart disease, hemoglobin was reduced in steps from 123 ± 8 (mean ± SD) to 98 ± 3 and to 79 ± 5 g/l. Hemodynamic measurements (intravascular pressures, thermodilution cardiac output, and echocardiographic recordings) were obtained during a stabilization period and at each level of hemodilution. Left ventricular wall motion was monitored continuously, and Doppler variables, annular motion, and changes in ejection fractional area were analyzed off-line.ResultsDuring hemodilution, cardiac output by thermodilution increased by 16 ± 7% and 26 ± 10%, corresponding well to the increase in cardiac output as measured by Doppler (difference, 0.32 ± 1.2 l/min). Systemic vascular resistance fell 16 ± 14% and 23 ± 9% and pulmonary capillary wedge pressure increased slightly (2 ± 2 mmHg), whereas other pressures, heart rate, wall motion, and diastolic Doppler variables remained unchanged. Ejection fractional area change increased from 44 ± 7% to 54 ± 10% and 60 ± 9% as a result of reduced end-systolic and increased end-diastolic left ventricular areas.ConclusionsA reduction in hemoglobin to 80 g/l during acute normovolemic hemodilution does not normally compromise systolic or diastolic myocardial function as determined by transesophageal echocardiography. Preload, left ventricular ejection fraction, and cardiac output increase with a concomitant fall in systemic vascular resistance.

ISSN:0003-3022    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

BackgroundThe neural mechanisms underlying the modulation of pain perception by hypnosis remain obscure. In this study, we used positron emission tomography in 11 healthy volunteers to identify the brain areas in which hypnosis modulates cerebral responses to a noxious stimulus.MethodsThe protocol used a factorial design with two factors: state (hypnotic state, resting state, mental imagery) and stimulation (warm non-noxiousvs.hot noxious stimuli applied to right thenar eminence). Two cerebral blood flow scans were obtained with the15O-water technique during each condition. After each scan, the subject was asked to rate pain sensation and unpleasantness. Statistical parametric mapping was used to determine the main effects of noxious stimulation and hypnotic state as well as state-by-stimulation interactions (i.e., brain areas that would be more or less activated in hypnosis than in control conditions, under noxious stimulation).ResultsHypnosis decreased both pain sensation and the unpleasantness of noxious stimuli. Noxious stimulation caused an increase in regional cerebral blood flow in the thalamic nuclei and anterior cingulate and insular cortices. The hypnotic state induced a significant activation of a right-sided extrastriate area and the anterior cingulate cortex. The interaction analysis showed that the activity in the anterior (mid-)cingulate cortex was related to pain perception and unpleasantness differently in the hypnotic state than in control situations.ConclusionsBoth intensity and unpleasantness of the noxious stimuli are reduced during the hypnotic state. In addition, hypnotic modulation of pain is mediated by the anterior cingulate cortex.

ISSN:0003-3022    

出版商:OVID    

年代:2000

数据来源: OVID