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BACKGROUND: Despite increasing use of tympanic thermometers in critically ill patients who do not have a pulmonary artery catheter in place, variations in measurements obtained with the thermometers are still a problem. OBJECTIVE: To compare the range of variability between tympanic and oral electronic thermometers. METHODS: Subjects were a convenience sample of 72 patients admitted to a 24-bed adult medical-surgical intensive care unit. For each patient, temperatures were measured concurrently (within a 1-minute period) with an oral (Sure Temp 678) thermometer, a pulmonary artery catheter (Baxter VIP Swan-Ganz Catheter), and 2 tympanic (FirstTemp Genius II and ThermoScan Ear Pro-1) thermometers. Each subject was used up to 3 times for data collection. Measurements obtained with the oral and tympanic thermometers were compared with those obtained with the pulmonary artery catheter. Nonparametric analysis of data was used. RESULTS: The magnitude of error for the ThermoScan tympanic thermometer differed significantly from that of the Genius II tympanic thermometer and the SureTemp oral thermometer (P < .001). Application of the Bland and Altman method to frame the data on the basis of an accuracy tolerance zone of +/-0.5 degrees C indicated variability with both the oral and tympanic methods. The overall degree of variability was lower for the oral thermometer. CONCLUSIONS: Oral thermometers provide less variable measurements than do tympanic thermometers. Use of oral thermometry is recommended as the best practice method for temperature evaluation in critical care patients when measurement of core temperature via a pulmonary artery catheter is not possible.

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Albino rats weighing 160 to 175 gm. were fed a complete synthetic diet containing 0.003 per cent potassium and 0.7 per cent sodium for 40 days. Controls were given the same diet plus adequate added potassium. 1. Data from analyses of serum and skeletal muscle showed (a) a fall in serum chloride concentration and an increase in serum carbon dioxide concentration and pH in the potassium-deficient rats; (b) increases of sodium, magnesium, and calcium and a decrease of potassium in the muscle of the potassium-deficient rats; (c) no change of muscle chloride or carbon dioxide concentrations in the potassium-deficient rats. (2) Application of the Wallace-Hastings calculations to these data revealed (a) intracellular pH of the skeletal muscle of the normal rat to be 6.98 ± 0.08; (b) an increase in serum partial pressure of carbon dioxide (pCO2) in potassium deficiency, together with increases in concentrations of [H2CO2] and [HCO3-] per kg. extracellular water and [H2CO3] per kg. cell water; (c) a decrease in values for [CO2] and [HCO3-] per kg. intracellular water; (d) a fall of intracellular pH in potassium deficiency to 6.42 ± 0.05. (3) Analyses of sacrospinalis muscle from five men undergoing operation for ruptured intervertebral disc showed a mean value of 9.46 ± 1.31 mM carbon dioxide per kg. blood-free tissue. Some problems of interpretation of data are briefly discussed.