Anesthesia and analgesia
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Anesthesia and analgesia · Oct 2000
Comparative Study Clinical Trial Controlled Clinical TrialThe lack of benefit of tracheal extubation in the operating room after coronary artery bypass surgery.
Although early tracheal extubation in cardiac anesthesia is safe and cost beneficial, questions still remain regarding how early after cardiac surgery patients should be tracheally extubated (TE). Our objective was to determine the effects on resource use if patients scheduled for coronary artery bypass grafting have TE in the operating room (OR). We studied 100 consecutive patients undergoing elective coronary artery bypass grafting, requiring extracorporeal circulation, and those eligible for a fast-track pathway. ⋯ Three patients (6%) in the OR group had postoperative myocardial infarction, and one postoperative myocardial infarction (2%) occurred in the ICU group (P = 0.61). All four patients recovered satisfactorily. The incidences of other complications were similar between groups.
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Anesthesia and analgesia · Oct 2000
Comparative StudyDefining segments and phases of a time capnogram.
The division of a time capnogram into inspiratory and expiratory segments is arbitrary and results in the inability of a time capnogram to detect rebreathing instantaneously. Demarcation of a time capnogram into inspiratory and expiratory components using gas flow signals will not only facilitate prompt detection of rebreathing, but will also allow application of standardized and physiologically appropriate nomenclature for better understanding and interpretation of time capnograms. A Novametrix((R)) CO(2)-SMO plus respiratory profile monitor (Novametrix Medical Systems, Wallingford, CT) was used to obtain a simultaneous display of CO(2) and respiratory flow waveforms on a computer screen during spontaneous and controlled ventilation using a circle system with the inspiratory valve competent (no rebreathing) and with the valve displaced (rebreathing). Because the response time of the CO(2) analyzer was similar to the response time of the flow sensor, a comparison was made between the two waveforms to determine the inspiratory segment (Phase 0) and the expiratory segment of the time capnogram and its subdivisions (Phases I, II, and III). The end of expiration almost coincides with the downslope of the CO(2) waveform in the capnograms when there is no rebreathing. However, in the presence of rebreathing, the alveolar plateau is prolonged and includes a part of inspiration (Phase 0), in addition to the expiratory alveolar plateau (Phase III). ⋯ Presently, the division of a time capnogram into inspiratory and expiratory segments is arbitrary. Demarcation of a time capnogram into various components using the gas flow signals facilitates prompt detection of the cause of abnormal capnograms that can widen the scope of future clinical applications of time capnography.
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Anesthesia and analgesia · Oct 2000
Comparative StudyThe epileptogenic properties of the volatile anesthetics sevoflurane and isoflurane in patients with epilepsy.
No study comparing epileptogenicity of sevoflurane to other volatile anesthetics has been performed. We compared the epileptogenic properties of sevoflurane to isoflurane in patients with epilepsy. In 24 mentally and/or physically disabled patients, 12 with epilepsy and 12 without epilepsy, electroencephalograms were recorded under anesthesia with 1.0 minimum alveolar anesthetic concentration (MAC), 1.5 MAC, and then 2.0 MAC sevoflurane or isoflurane under three ventilatory conditions: (A) 100% oxygen, and end-tidal CO(2) partial pressure (ETCO(2)) = 40 mm Hg, (B) 50% oxygen, 50% nitrous oxide, ETCO(2) = 40 mm Hg, and (C) 100% oxygen, ETCO(2) = 20 mm Hg. Spike activity was evaluated as a spike-and-wave index (% durations of spike and wave). The spike-and-wave index increased (P<0.05) from 1.99%+/-0.96% during 1.0 MAC sevoflurane to 6.14% +/- 4.45% during 2.0 MAC sevoflurane in (A) in the epilepsy group, while no spike activity was observed in the nonepilepsy group. Only a few spikes were observed under isoflurane anesthesia, 0.04% +/- 0.04% in (A), with no spikes in (B) and (C). Supplementation with 50% nitrous oxide or hyperventilation (P<0.05) suppressed the occurrence of spikes. Sevoflurane has a stronger epileptogenic property than isoflurane, but nitrous oxide or hyperventilation counteracts this specific epileptogenic property. ⋯ The stronger epileptogenicity of sevoflurane than isoflurane was confirmed in a controlled study in patients with epilepsy. Hyperventilation and supplementation of nitrous oxide under sevoflurane anesthesia suppressed epileptogenicity. A combination of sevoflurane and nitrous oxide may be a safer method for seizure-prone patients than the use of sevoflurane alone.
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Anesthesia and analgesia · Oct 2000
The efficacy and safety of EMLA cream for awake fiberoptic endotracheal intubation.
EMLA Cream (EC; Astra, Westborough, MA) has been widely used as a local anesthetic. Limited safety information is available with respect to the application of EC to the oral mucous membranes. The purpose of this pilot study was to evaluate the efficacy and safety of EC when applied to oral mucosa for fiberoptic intubation. ⋯ The measured peak plasma concentration of lidocaine or prilocaine did not reach toxic levels in any patient. Methemoglobin levels did not exceed normal values (1.5%) in any patient, and there was no relationship between methemoglobin levels and patient weight, amount of EC used, measured peak plasma concentration, or times to measured peak concentrations of prilocaine or lidocaine. We conclude that EC provided satisfactory topical anesthesia allowing for successful oral fiberoptic intubation in all patients and should be considered a safe alternative for anesthetizing the airway of patients requiring awake oral fiberoptic intubation.
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Anesthesia and analgesia · Oct 2000
Comparative StudyThe effect of sedative drugs on diaphragmatic contractility in dogs: propofol versus midazolam.
a sedative dose (0.1 mg x kg(-1) x h(-1)) of midazolam, compared with a subhypnotic dose (1.5 mg x kg(-1) x h(-1)) of propofol, decreases the contractility of the diaphragm in dogs.