Accuracy of chemical dot thermometers in critically ill adults and young children.

Chemical dot thermometers are used widely, but their clinical accuracy is not well documented. Temperature measurements with chemical dot and electronic thermometers were compared at the oral site in 27 adults and the axillary site in 44 adults and 34 young children in critical care units. In adults, mean readings with chemical dot thermometers were lower by -0.4 degrees C orally, but higher by 0.4 degrees C in the axilla. Axillary readings in children did not differ significantly with the two methods, although individual differences of +/- 0.4 degrees C or more were common. Chemical dot thermometers provided rough temperature estimates, performing differently at the oral and axillary sites and in the two age groups.

Accuracy of infrared ear thermometry and other temperature methods in adults.

OBJECTIVE: To compare the accuracy of infrared ear-based temperature measurement in relation to thermometer, ear position, and other temperature methods, with pulmonary artery temperature as the reference. METHODS: Ear-based temperature measurements were made with four infrared thermometers, three in the core mode and two in the unadjusted mode, each with tug and no-tug techniques. Pulmonary artery, bladder (n = 21), and axillary temperatures were read after each ear-based measurement and oral temperature was measured once when possible (n = 32). Subjects consisted of a convenience sample of 50 patients with pulmonary artery catheters who were in adult critical care units of a university teaching hospital. RESULTS: Ear-based measurements correlated well with pulmonary artery temperature (r = .87 to .91), although closeness of agreement differed among thermometer-mode combinations (mean offsets = -0.7 to 0.5 degree C) and had moderately high variability between subjects (SD = +/- 0.5 degree C) with all instruments. Use of an ear tug either made no difference or resulted in slightly lower readings. Bladder temperature was nearly identical to pulmonary artery temperature values (r = .99, offset = 0.0 +/- 0.2 degree C). Oral readings were slightly lower (r = .78, offset = -0.2 degree C) and axillary readings much more so (r = .80 to .82, offset = -0.7 degree C); both were highly variable (SD = +/- 0.6 degree C) and affected by external factors. CONCLUSIONS: Infrared ear thermometry is useful for clinical temperature measurement as long as moderately high variability between patients is acceptable. Readings differ among thermometers, although several instruments provide values close to pulmonary artery temperature in adults. Readings are not higher with an ear tug. Bladder temperature substitutes well for pulmonary artery temperature, whereas oral and axillary values may be influenced by external factors in the critical care setting.

Injectate port selection affects accuracy and reproducibility of cardiac output measurements with multiport thermodilution pulmonary artery catheters.

OBJECTIVE: To compare the accuracy and reproducibility of thermodilution cardiac output measurements obtained from the injectate and infusion ports of a multilumen pulmonary artery catheter. The thermodilution results were compared with an independent measure of flow obtained from an electromagnetic flow meter. METHODS: In an experimental study conducted at an animal research laboratory of a health sciences university, two virgin western breed ewes were surgically instrumented with an inferior vena cava occluder, which reduced venous return and thus lowered cardiac output, and an ascending aortic electromagnetic flow probe, which provided an independent reference measure of cardiac output. On the day of study, a multilumen pulmonary artery catheter was inserted. Cardiac output was manipulated over a range of 2.9 to 12.1 L/min with i.v. isoproterenol or inferior vena cava occlusion. Approximately 30 simultaneous thermodilution and electromagnetic flow meter measurements of cardiac output were obtained from both the infusion and injectate ports in each of the two subjects. RESULTS: Correlation coefficients were lower and standard error of the estimates was higher for the infusion port (r = .83; SEE = 1.19 L/min) vs the injectate port (r = .94; SEE = .74 L/min), indicating reduced reproducibility with infusion port thermodilution cardiac output determinations. Accuracy was also adversely influenced in the infusion port results. The linear regression for the infusion port data intercepted the Y axis at +2.64 L/min, indicating significant overestimation of cardiac output at flows of less than 5 L/min and underestimation of flow when cardiac output exceeded 8 L/min. CONCLUSIONS: The use of the infusion port for the measurement of thermodilution cardiac output measurements may result in nonreproducible and inaccurate results.

Treatment of paroxysmal supraventricular tachycardia with adenosine: implications for nursing.

Paroxysmal supraventricular tachycardia (PSVT) is a frequently occurring arrhythmia. Currently, verapamil and manual vagal stimulation are the first-line interventions for PSVT. Although verapamil is widely used for the treatment of PSVT, it can result in hypotension and ventricular fibrillation if given to a patient with ventricular tachycardia. Because the differential diagnosis of broad QRS complex tachycardia is difficult, the development of a safer drug for the treatment of both narrow- and broad-complex tachycardia is extremely important. Adenosine is a promising new drug for the treatment of PSVT. Its use is reviewed in three presentations.