Anesthesia and analgesia
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Anesthesia and analgesia · May 2005
Electroencephalogram monitoring during anesthesia with propofol and alfentanil: the impact of second order spectral analysis.
Bispectral analysis of the electroencephalogram (EEG) has been used for monitoring anesthesia. The estimation of bicoherence allows us to determine whether a given time series represents a linear random process in cases where the bicoherence is trivial, i.e., a mere constant independent of frequency. In this study, we investigated the proportion of EEG epochs with nontrivial bicoherence during surgical anesthesia with propofol and alfentanil as an indicator for the degree of nonlinearity in the EEG. ⋯ Under these conditions, the EEG can be considered as a linear random process. Our findings suggest that the spectral information in the frequency domain delivered by the EEG monitoring during anesthesia is largely contained in the power spectrum of the signal. This calls into question the benefit of EEG bispectral analysis for monitoring anesthesia effect.
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Anesthesia and analgesia · May 2005
Cost-effectiveness of routine intraoperative transesophageal echocardiography in pediatric cardiac surgery: a 10-year experience.
The beneficial effect of transesophageal echocardiography (TEE) on medical and surgical treatment of children with congenital heart disease has been established. Its cost-effectiveness, however, has not been extensively studied. We analyzed reports of 580 routine TEE examinations performed in our institution between January 1994 and December 2003 in patients younger than 17 yr who required congenital cardiac surgery. ⋯ This figure undoubtedly underestimates the true cost-effectiveness of routine intraoperative TEE in this setting because we used mostly conservative estimates of the benefits and liberal estimates of the costs. The potential benefits of TEE in hemodynamic monitoring and medical management, in reduction of postoperative morbidity, and in improvement in the quality of life are intangible and were not considered. Although benefits and costs vary according to market conditions, patient populations, surgical practice, and technical expertise with TEE, our analysis demonstrates substantial cost-effectiveness in the use of routine TEE during pediatric cardiac surgery.
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Anesthesia and analgesia · May 2005
Neurologic sequelae after interscalene brachial plexus block for shoulder/upper arm surgery: the association of patient, anesthetic, and surgical factors to the incidence and clinical course.
We determined the incidence, distribution, and resolution of neurologic sequelae and the association with anesthetic, surgical, and patient factors after single-injection interscalene block (ISB) using levobupivacaine 0.625% with epinephrine 1:200,000 in subjects undergoing shoulder or upper arm surgery, or both, in 693 consecutive adult patients. After a standardized ISB, assessments were made at 24 and 48 h and at 2 and 4 wk for anesthesia, hypesthesia, paresthesias, pain/dysesthesias, and motor weakness. Symptomatic patients were monitored until resolution. ⋯ Variables identified as independent predictors of neurologic sequelae likely related to ISB were paresthesia at needle insertion and ISB site pain or bruising at 24 h. In contrast, surgery preformed in the sitting position, as well as ISB site bruising, was identified as a predictor of neurologic sequelae not likely related to ISB. In conclusion, neurologic sequelae after single-injection ISB using epinephrine mainly involve transient minor sensory symptoms.
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The nasal route is preferred for fiberoptic intubation. Placing a lubricated endotracheal tube through the nostril can guide the fiberoptic scope towards the larynx. It would be helpful for optimal visualization of the vocal cord when the scope is passed through the endotracheal tube if the length of nares-vocal cord (NV length) could be predicted and the tip of the endotracheal tube could be placed close to the vocal cord. ⋯ The NV length of the males was 18.3 +/- 0.8 cm, and that of the females was 16.3 +/- 0.7 cm. The relationship between the NV length and body height (P < 0.001, r = 0.755) and the NE distance (P < 0.001, r = 0.636) showed a significant correlation but NM distance did not (P = 0.075). The length of the NV cord can be predicted using the body height or the NE distance.
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Anesthesia and analgesia · May 2005
The quantitative distinction between train-of-four "counts of 2" and posttetanic "counts of 2" evidenced by a stable paralysis/stable infusion rate method in anesthetized patients receiving mivacurium.
In this study we quantitatively evaluated, by a stable paralysis/stable infusion rate method, the difference between two standardized paralysis levels--train-of-four (TOF) count of 2 responses and posttetanic count (PTC) of 2. Ten ASA physical status I-II consenting adult patients scheduled for elective surgery were anesthetized (sufentanil/propofol), tracheally intubated, mechanically normoventilated with a fixed O(2)/air mixture, and normothermic; oropharynx and thenar temperatures were maintained above 36 degrees and 32.5 degrees C, respectively. ⋯ Infusion rates observed were: TOF count 2-6 (2-11) and PTC 2-17 (3-18) microg . kg(-1) . min(-1) (P < 0.001; Wilcoxon's paired comparison test). Under the present conditions, obtaining and maintaining a PTC of 2 requires MIV infusion rates far in excess of the "standard" recommendations mentioned in the literature for MIV infusion management.