title: A comparison of 2 methods of measuring rectal temperatures with digital thermometers.
abstract: BACKGROUND
  Digital rectal thermometers typically have 2 distinct modes of operation: dwell or monitor, in which body temperature is displayed continuously, and predictive, in which body temperature is mathematically estimated on the basis of the curve of temperature rise that occurs after the thermometer is inserted. Although the dwell mode is generally considered more accurate, the predictive mode allows more rapid measurement. Direct comparisons of these 2 methods are lacking.
  
  
  OBJECTIVE
  To determine if measurements of rectal temperatures obtained with the predictive mode differ significantly from those obtained with the dwell mode.
  
  
  METHODS
  For each of 10 subjects, both dwell and predictive modes were used to measure early morning rectal temperature. For comparison of the 2 modes during states of temperature flux, 8 subjects had rectal temperatures measured after swimming in cold water. Initial predictive values were measured directly after each subject exited from the water. Initial dwell values were estimated by linear extrapolation of measured 3- and 6-minute dwell values. Paired-sample statistical methods were used to compare data.
  
  
  RESULTS
  Measurements of early-morning temperatures obtained with the predictive mode did not differ significantly from those obtained with the dwell mode (P = .64). Predictive values also did not differ significantly from extrapolated dwell values for measurements obtained during mild temperature flux after immersion in cold water (P = .33).
  
  
  CONCLUSIONS
  The predictive and dwell modes of digital rectal thermometers yield similar measurements of temperature during steady-state conditions and during states of mild temperature flux.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, University of California, San Francisco, Calif., USA.
authors.forename: T J
authors.initials: TJ
authors.lastname: Nuckton
authors.forename: D
authors.initials: D
authors.lastname: Goldreich
authors.forename: F C
authors.initials: FC
authors.lastname: Wendt
authors.forename: J G
authors.initials: JG
authors.lastname: Nuckton
authors.forename: D M
authors.initials: DM
authors.lastname: Claman
mesh_terms: D000328:Adult; D000368:Aged; D001831:Body Temperature; D001833:Body Temperature Regulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012007:Rectum; D013550:Swimming; D013821:Thermometers