Articles: general-anesthesia.
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Randomized Controlled Trial Clinical Trial
Isoflurane with either 100% oxygen or 50% nitrous oxide in oxygen for caesarean section.
Two hundred mothers undergoing general anaesthesia for Caesarean section were allocated randomly to receive either 100% oxygen (group 100) or 50% nitrous oxide in oxygen (group 50), both supplemented with isoflurane. In each group the concentrations of isoflurane were chosen to deliver 1.5 MAC for the first 5 min after induction and 1.0 MAC thereafter. The mean umbilical venous PO2 was greater in group 100 for emergency sections (P = 0.001). ⋯ There were no instances of awareness, although two patients in group 100 and three in group 50 reported dreaming. This study confirms earlier findings that the use of 100% oxygen can significantly improve fetal oxygenation during Caesarean section, with particular benefit in emergency cases. This is associated with a lower incidence of neonatal resuscitation.
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Liquid crystal thermometry (LCT) is a non-invasive alternative to temperature monitoring. We evaluated the ability of forehead LCT, rectal temperature, and axillary skin temperature to trend distal oesophageal temperature during rapid warming on cardiopulmonary bypass. ⋯ Polynomial regression analysis revealed that LCT, but not axillary or rectal temperatures, correlated with oesophageal temperature. We conclude that forehead LCT may be useful to monitor temperature trends and to detect rapid elevations in body temperature when more invasive temperature monitoring is inappropriate or unavailable.
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We have investigated the value of lower oesophageal contractility (LOC) in detecting awareness during anaesthesia in 20 human volunteer patients. LOC was measured either with subjects awake or after induction with propofol, during induction with propofol, and then as consciousness returned. Statistically significant changes were observed in the frequency of spontaneous contractions, peak and mean amplitude of spontaneous and provoked contractions, and the oesophageal contractility index as subjects lost consciousness and also as it was regained. The differences in LOC which occurred when subjects were conscious and unconscious support the view that LOC is related to the depth of anaesthesia, but its unreliability at the interface between consciousness and unconsciousness prevents selective detection of awareness, although the response in the presence of painful stimuli has not been tested.
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It has been shown that a variable percentage of patients who receive a general anesthetic are significantly hypoxemic when they arrive at the recovery room. Pulse oximetry has proved to be a reliable method to determine arterial oxygen saturation when compared to arterial or mixed venous blood oxygen saturation measurements. The authors determined the incidence and severity of hypoxemia by pulse oximetry in 45 healthy adult patients, (non obese, non smokers) who underwent non thoracic surgery under general anesthesia. ⋯ The authors conclude that a significant number of healthy adult patients who are given a general anesthetic show severe hypoxemia when they arrive at the recovery room. The severe hypothermia found in these patients can aggravate the hypoxemia. They consider it is mandatory to control the temperature of and to administer oxygen in the recovery room to all patients who receive a general anesthetic.
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J. Oral Maxillofac. Surg. · Aug 1990
Randomized Controlled Trial Comparative Study Clinical TrialPreanesthetic medication with rectal midazolam in children undergoing dental extractions.
Three different dosages (0.25, 0.35, and 0.45 mg/kg) of rectally administered midazolam were compared with each other and with placebo for preanesthetic medication in children undergoing dental extractions. Eighty patients between the ages of 2 and 10 years were randomly allocated into four groups in this double-blind study. ⋯ A high prevalence (23%) of disinhibition reactions was observed, particularly in the 0.45 mg/kg group. For this reason, 0.25 or 0.35 mg/kg appears to be the dose of choice when rectal midazolam is used for premedication in children.