Articles: general-anesthesia.
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Thermoregulatory responses in infants and children are now fairly well understood. The phenomenon of heat loss in children during surgery is widely acknowledged. Hypothermia is most likely to occur during long surgical procedures in an air-conditioned operating room, particularly when respiration is controlled. ⋯ Perioperative hypothermia results from decreased metabolic heat production, increased environmental heat loss, redistribution of heat within the body, and anesthesia-induced inhibition of thermoregulation. Radiation and convection from the skin surface combine with evaporation from tissues inside surgical incisions to decrease mean body temperature. Perioperative hypothermia can be limited by prewarming the skin surface before induction of anesthesia, warming the operating room, humidifying the airway, and warming intravenous fluids.
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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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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.