Articles: general-anesthesia.
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Acta Anaesthesiol Scand · Jan 1992
Comparative StudyDoes the anesthetic method influence the postoperative breathing pattern and gas exchange in hip surgery? A comparison between general and spinal anesthesia.
We studied the effects of elective hip surgery, performed under either spinal (SA, n = 10) or general anesthesia (GA, n = 10), on breathing pattern and gas exchange. Measurements were made with respiratory inductive plethysmograph and indirect calorimetry in two positions before and after surgery. The method of anesthesia had no effect on the severity of postoperative hypoxemia. ⋯ The contribution of rib cage to tidal volume increased postoperatively in the supine position (P less than 0.001; SA from 32.6% +/- 10.3 to 46.3% +/- 7.5, GA from 36.5 +/- 16.4 to 48.5% +/- 15.4). CO2 production, oxygen consumption and energy expenditure remained unchanged. The postoperative changes in breathing pattern are related to the operation, not to the type of anesthesia and do not explain the alterations in gas exchange.
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Randomized Controlled Trial Clinical Trial
Accelographic train-of-four at near-threshold currents.
The authors evaluated train-of-four (TOF) fade, as quantified by accelography, in response to neurostimulation at currents ranging from 10 to 60 mA. This was done to determine the range of currents over which measurements of fade remain consistent. In 31 patients (ASA Physical Status 1,2, and 3), anesthesia was induced with fentanyl, midazolam, and thiopental and was maintained with isoflurane and 66% nitrous oxide in oxygen. ⋯ This inconsistency was eliminated by testing at greater than or equal to 10 mA above threshold. TOF ratios obtained at 10 mA above T4 threshold correlated highly with those at 60 mA (Spearman r value = 0.94). The authors conclude that the TOF ratio is consistent over a wide range of stimulating currents and that testing with submaximal currents can be performed reliably at greater than or equal to 10 mA above the T4 threshold.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Clinical Trial
[The effect of halothane, alfentanil and propofol on blood flow velocity, blood vessel cross section and blood volume flow in the middle cerebral artery].
Transcranial Doppler sonography (TCD) has gained in relevance for noninvasive monitoring of the cerebral circulation during the perioperative period. As long as the diameters of the investigated vessels remain unknown, however, flow velocities alone are not really informative. Exact vessel diameter determination in humans under the influence of different anesthetic drugs has not yet been performed due to ethical and methodological restrictions. ⋯ LAR remained unaltered after alfentanil administration. The site of action of some anesthetic agents on cerebral vessels does not seem to be restricted to cerebral arterioles: at least for halothane, a vasodilating effect on large cerebral arteries could be demonstrated. This should be kept in mind when transcranial Doppler is applied during the perioperative period.
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Anesth Pain Control Dent · Jan 1992
Multicenter StudyProtocol for studying depth of anesthesia using the spectral edge frequency.
The preliminary results of a multicenter study designed to determine the utility of the processed EEG in combination with heart rate and blood pressure for estimating anesthetic depth are reported. The study is planned to include 1,000 ASA I, II, and III patients undergoing surgery with at least a 60-minute duration of anesthesia. The preliminary results indicate that the use of EEG and clinical signs may provide better control of anesthetic depth. The study design provides ideal conditions for determining whether spectral edge frequency is a useful criterion for management of routine general anesthesia in a typical clinical environment.
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Anesthesia progress · Jan 1992
Comparative StudySupplemental oxygen after outpatient oral and maxillofacial surgery.
Arterial oxygen saturation (SpO2) was monitored postoperatively with pulse oximetry in 72 dental patients. Intravenous general anesthesia was employed in 57 patients. All of these patients received supplemental oxygen intraoperatively, and of these, 29 received supplemental oxygen postoperatively. ⋯ Patients with a smoking history had more episodes of desaturation than did nonsmokers in the group that received general anesthesia and breathed room air postoperatively. The total amount of methohexital administered had no significant effect on the number of patients with desaturation episodes. These observations emphasize the need for postoperative oxygen for patients who undergo general anesthesia for outpatient oral and maxillofacial surgery.