Effect of hot and cold fluids on oral temperatures

Nursing textbooks have differed in recommendations for length of time (10 to 30 minutes) to wait to take the patient's temperature after he has ingest hot or cold food or fluids. It would appear either that inaccurate temperatures are recorded or that an excessive amount of time has been recommended. The purpose of this study was to determine the length of time required for the oral temperature to return to an established baseline after ingestion of hot and cold fluids. The sample consisted of 13 female and 12 male subjects with an age range of 20 to 52 years. All subjects were afebrile. Hot chocolate at a mean temperature of 131 degrees Fahrenheit and iced water at 34 degrees Fahrenheit were ingested by the subjects after a baseline temperature was established. Oral temperatures were recorded every 15 seconds by means of a pretested telethermometer until a constant temperature was maintained for a 10 minute period. In analyzing results, a variation of 0.2 degree was not considered significant because of error of 0.2 degree in reading a clinical thermometer could be made and because medical diagnosis and therapy do not depend on this minute variation. Means and standard deviations of the time required for attainment of point 0.2 degree from the terminal baseline were determined. The assumption the 98 percent (two standard deviations) of people's temperature would reach that point in 26.9 minutes after ingestion of hot fluids and 27.80 minutes after cold fluids was made. The implication for nursing practice to drawn from this study is that to ensure accuracy of temperature measurement, the nurse should wait 30 minutes before recording the oral temperature.