Anesthesia and analgesia
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Anesthesia and analgesia · Aug 1989
Randomized Controlled Trial Clinical TrialIntraoperative temperature monitoring sites in infants and children and the effect of inspired gas warming on esophageal temperature.
This study tested the hypotheses that 1) temperatures of "central" sites are similar in infants and children undergoing noncardiac surgery and 2) airway heating and humidification increases distal esophageal temperature. Twenty children were randomly assigned to receive 1) active airway humidification using an airway heater and humidifier set at 37 degrees C (N = 8), 2) passive airway humidification using a heat and moisture exchanger (N = 6), or 3) no airway humidification and/or heating (control, N = 6). There were no statistically significant differences between tympanic membrane, esophageal, rectal, and axillary temperatures. ⋯ Although esophageal and tympanic membrane temperatures in the entire group were similar, esophageal temperatures in patients receiving active and passive airway humidification were about 0.35 degrees C above tympanic temperatures after induction of anesthesia. In contrast, esophageal temperatures in patients without airway humidification were 0.25 degrees C below tympanic temperatures after induction of anesthesia. Esophageal-tympanic membrane temperature differences in the patients given active and passive humidification differed significantly from the corresponding sum in the control group at all times, but not from each other.
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Anesthesia and analgesia · Aug 1989
Randomized Controlled Trial Clinical TrialEarly postoperative arterial oxygen desaturation. Determining factors and response to oxygen therapy.
Oxygen arterial saturation (SaO2) was measured with a pulse oximeter in 209 patients after elective surgery. Measurements were made upon arrival in the recovery room (RR) and 1 hr later. On each occasion, the patients randomly and alternately breathed--for 10 min at a time--room air or 35% O2. ⋯ Postoperative hypoxemia (SaO2 less than or equal to 90%) after breathing room air for 10 min at 10 min, 20 min, and 1 hr after arrival in the RR occurred in 43.8%, 26.9%, and 16.9% of the patients, respectively. Breathing 35% O2 for 10 min 10 min after arrival in the RR, as well as 20 min and 1 hr after arrival, significantly increased SaO2 above the SaO2 level after breathing room air by 5.7% (P less than 0.001), 4.3% (P less than 0.001), and 4.0% (P less than 0.001), respectively. A significant multiple correlation was found between low SaO2 levels while breathing room air on arrival in the RR and fentanyl dose, age, and concentration of halothane used intraoperatively (R = 0.46; P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
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Anesthesia and analgesia · Aug 1989
Tachyphylaxis associated with repeated epidural injections of lidocaine is not related to changes in distribution or the rate of elimination from the epidural space.
The relationship between tachyphylaxis (measured as a decrease in the rate of regression of sensory levels of analgesia) during repeated epidural injections of lidocaine and both the distribution of lidocaine within the epidural space (as measured by spread of simultaneous injection of the tracer technetium-99m diethylenetriaminepentaacetate [99mTc-DTPA]) and elimination of lidocaine from the epidural space (as measured by serum concentrations of lidocaine) was investigated in 18 patients undergoing minor surgery during lumbar epidural analgesia. Twelve patients received four injections of 20 mL of 2% lidocaine at 2-hr intervals. ⋯ In another six patients 20 mL of 2% lidocaine were injected three times at 2-hr intervals before surgery, with measurements of serum concentrations of lidocaine after the first and last injections. Despite tachyphylaxis (no patient had sensory analgesia 2 hr after the third injection), there was no difference in the rate of disappearance of lidocaine from the epidural space as assessed by plasma lidocaine concentration curves during the first and third injection (0.5 +/- 0.1 and 0.3 +/- 0.04 microgram.mL-1.min-1, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)