***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: OBJECTIVES To investigate the clinical accuracy of infrared ear thermometer derived and equilibrated rectal temperatures in estimating core body temperature . The clinical bias ( i.e. , mean difference between body sites ) , and variability ( SD of the differences ) of simultaneous temperatures were compared with pulmonary artery temperatures . Clinical repeatability ( pooled SD of triplicate reading differences ) was also examined for three ear infrared thermometers . DESIGN Prospect i ve clinical study . SETTING A multidisciplinary , adult intensive care unit . PATIENTS Twenty patients with an existing pulmonary artery catheter were studied in a multidisciplinary , adult intensive care unit . INTERVENTIONS A single operator using optimum ear infrared technique and masked to ear and rectal temperatures recorded triplicate measurements with each of three infrared ear thermometers , each over a 4-min period with each infrared thermometer , while an assistant recorded temperatures . Infrared and rectal temperatures were compared with a simultaneous pulmonary artery temperature . MEASUREMENTS AND MAIN RESULTS Infrared ear thermometers and rectal thermometers were calibrated daily , and pulmonary artery catheters were calibrated on removal from the patient . Patients were grouped into afebrile and febrile groups , based on initial pulmonary artery temperature .  Bias and variability were compared between thermometers using analysis of variance . Clinical bias , but not variability , was significantly different between three ear infrared thermometers ( 0.16 + /- 0.46 degrees C , 0.07 + /- 0.38 degrees C , and -0.22 + /- 0.47 degrees C ) . The repeatability was not different between ear infrared thermometers ( range 0.13 degrees C to 0.14 degrees C ) . Rectal temperature had a significantly greater bias ( average 0.3 degrees C ) , but less variability ( average 0.2 degrees C ) . Bias was increased , and variability decreased for both rectal and infrared ear temperatures when pulmonary artery temperature was increased . CONCLUSIONS The three infrared ear thermometers studied provided a closer estimate of core body temperature than equilibrated rectal temperature . Clinical bias was greatest in febrile vs. afebrile intensive care unit patients Objective : Accurate measurement of temperature is vital in the intensive care setting . A prospect i ve trial was performed to compare the accuracy of tympanic , urinary , and axillary temperatures with that of pulmonary artery ( PA ) core temperature measurements . Design : A total of 110 patients were enrolled in a prospect i ve observational cohort study . Setting : Multidisciplinary intensive care unit of a university teaching hospital . Patients : The cohort was ( mean ± sd ) 65 ± 16 yrs of age , Acute Physiology and Chronic Health Evaluation ( APACHE ) II score was 25 ± 9 , 58 % of the patients were men , and 76 % were mechanically ventilated . The accuracy of tympanic ( averaged over both ears ) , axillary ( averaged over both sides ) , and urinary temperatures was referenced ( as mean difference , & Dgr ; degrees centi grade ) to PA temperatures as st and ard in 6,703 recordings . Lin concordance correlation ( pc ) and Bl and –Altman 95 % limits of agreement ( degrees centi grade ) described the relationship between paired measurements . Regression analysis ( linear mixed model ) assessed covariate confounding with respect to temperature modes and reliability formulated as an intraclass correlation coefficient . Measurements and Main Results : Concordance of PA temperatures with tympanic , urinary , and axillary was 0.77 , 0.92 , and 0.83 , respectively . Compared with PA temperatures , & Dgr ; ( limits of agreement ) were 0.36 ° C ( −0.56 ° C , 1.28 ° C ) , −0.05 ° C ( −0.69 ° C , 0.59 ° C ) , and 0.30 ° C ( −0.42 ° C , 1.01 ° C ) for tympanic , urinary , and axillary temperatures , respectively . Temperature measurement mode effect , estimated via regression analysis , was consistent with concordance and & Dgr ; ( PA vs. urinary , p = .98 ) . Patient age ( p = .03 ) , sedation score ( p = .0001 ) , and dialysis ( p = .0001 ) had modest negative relations with temperature ; quadratic relationships were identified with adrenaline and dobutamine . No interactions with particular temperature modes were identified ( p ≥ .12 for all comparisons ) and no relationship was identified with either mean arterial pressure or APACHE II score ( p ≥ .64 ) . The average temperature mode intraclass correlation coefficient for test – retest reliability was 0.72 . Conclusion : Agreement of tympanic with pulmonary temperature was inferior to that of urinary temperature , which , on overall assessment , seemed more likely to reflect PA core temperature Objective . Comparisons of urinary bladder , oesophageal , rectal , axillary , and inguinal temperatures versus pulmonary artery temperature . Design . Prospect i ve cohort study . Setting . Intensive Care Unit of a University-Hospital . Patients . Forty-two intensive care patients requiring a pulmonary artery catheter (PAC).Intervention  . Patients requiring PAC and without oesophageal , urinary bladder , and /or rectal disease or recent surgery were included in the study .  Temperature was simultaneously monitored with PAC , urinary , oesophageal , and rectal electronic thermometers and with axillary and inguinal gallium-in-glass thermometers . Comparisons used a Bl and and Altman method . Measurements and main results . The pulmonary arterial temperature ranged from 33.7 ° C to 40.2 ° C . Urinary bladder temperature was assessed in the last 22 patients . A total of 529 temperature measurement comparisons were carried out ( 252 comparisons of esophageal , rectal , inguinal , axillary , and pulmonary artery temperature measurements in the first 20 patients , and 277 comparisons with overall methods in the last patients ) . Nine to 18 temperature measurement comparisons were carried out per patient ( median = 13 ) . The mean differences between pulmonary artery temperatures and those of the different methods studied were : oesophageal ( 0.11±0.30 ° C ) , rectal ( −0.07±0.40 ° C ) , axillary ( 0.27±0.45 ° C ) , inguinal ( 0.17±0.48 ° C ) , urinary bladder ( −0.21±0.20 ° C ) . Conclusion . In critically ill patients , urinary bladder and oesophageal electronic thermometers are more reliable than the electronic rectal thermometer which is better than inguinal and axillary gallium-in-glass thermometers to measure core temperature Objective : To determine the epidemiology of fever on the intensive care unit ( ICU ) . Design : Prospect i ve , observational study . Setting : Nine-bed general ICU in a 500-bed tertiary care inner city institution . Patients : 100 consecutive admissions of 93 patients over a 4-month period between July and October 1996 . Interventions : All patients were seen and examined by one investigator within 24 h of ICU admission . Patients were followed up on a daily basis throughout their ICU stay , and all clinical and laboratory data were recorded during the admission . Measurements and results : Fever ( core temperature ≥ 38.4 ° C ) was present in 70 % of admissions , and it was caused by infective and non-infective processes in approximately equal number . Most fevers occurred early in the course of the admission , within the first 1–2 days , and most lasted less than 5 days . The median Acute Physiology and Chronic Health Evaluation ( APACHE ) II score was 15 ( ± 0.6 ) . The 70 episodes associated with fever at any time were associated with a significantly higher APACHE II score on admission than the afebrile episodes ( 15.8 ± 6.1 vs 12.1 ± 6.7 , p = 0.04 ) . The most common cause of non-infective fever was in the group design ated post-operative fever ( n = 34 ) . All the patients in the post-operative fever group were febrile on day 0 or day 1 ; their mean admission APACHE score was 12.4 ( ± 4.4 ) compared to 15.9 ( ± 7.1 ) for the remaining patients ( p = 0.01 ) . Fever alone was not associated with a higher mortality : 26/70 ( 37 % ) of febrile patients died , compared to 8/30 ( 27 % ) of afebrile patients , ( χ2 = 1.23 , p = 0.38 ) . Prolonged fever ( > 5 days ) occurred in 16 patients . In 13 cases , fever was due to infection , and in the remaining 3 both infective and non-infective processes occurred concurrently . The mortality in the group with prolonged fever was 62.5 % ( 10/16 ) compared to 29.6 % ( 16/54 ) in patients with fever of less than 5 days ' duration , a highly significant difference ( p < 0.0001 ) . Conclusions : Fever is a common event on the intensive care unit . It usually occurs early in the course , is frequently non-infective and is often benign . Prolonged fever is associated with a poor outcome . Post-operative fever is a well-recognised but poorly defined syndrome which requires further study To determine the accuracy and repeatability of ear-based , bladder , oral , and axillary temperature methods . Design : Prospect i ve , descriptive comparison of the accuracy of four temperature methods in relation to pulmonary artery temperature and the repeatability of each method . Setting : Critical care units of a university teaching hospital . Patients : Convenience sample of 38 adult patients with indwelling pulmonary artery thermistor catheters . Interventions : None . Measurements and Main Results : Ear-based estimates of core temperature with an infrared thermometer and pulmonary artery , bladder , oral , and axillary temperatures with thermistor-based instruments were made every 20 mins for 4 hrs . Mean offsets ( ± SD ) from pulmonary artery temperature for each method were as follows : ear-based 0.07 ± 0.41 ° C ; bladder 0.03 ± 0.23 ° C ; oral 0.05 ± 0.26 ° C ; and axillary −0.68 ± 0.57 ° C . The accuracy of each method varied with the level of pulmonary artery temperature . Repeated measurements with all four methods had mean SD values within ±0.2 ° C . Conclusions : Infrared ear thermometry provided a relatively close estimate of pulmonary artery core temperature , although with more variability than bladder or oral methods , while axillary readings were substantially lower than the pulmonary artery temperature and highly variable . ( Crit Care Med 1993 ; 21:1528–1534 BACKGROUND A clinical ly useful temperature measurement method should correlate well with the body 's core temperature . Although previous investigators have studied temperature readings from different sites in hypothermic and normothermic patients , none have compared methods specifically in febrile patients . OBJECTIVE To compare temperature measurement methods in febrile intensive care patients . METHODS  Temperature readings  were obtained in rapid sequence from an electronic thermometer for oral and axillary temperature , rectal probe , infrared ear thermometer on " core " setting , and pulmonary artery catheter , approximately every hour during the day and every 4 hours at night . The sample consisted of 13 patients with pulmonary artery catheters and with temperatures of at least 37.8 degrees C. RESULTS Rectal temperature correlated most closely with pulmonary artery temperature . Rectal temperature showed closest agreement with pulmonary artery temperature , followed by oral , ear-based , and axillary temperatures . Rectal and ear-based temperatures were most sensitive in detecting temperatures greater than 38.3 degrees C. Likelihood ratios for detecting hyperthermia were 5.32 for oral , 2.46 for rectal , and 1.97 for ear-based temperature . Rectal and ear-based temperatures had the lowest negative likelihood ratios , indicating the least chance of a false negative reading . Axillary temperature had a negative likelihood ratio of 0.86 . CONCLUSIONS Rectal temperature measurement correlates most closely with core temperature . If the rectal site is contraindicated , oral or ear-based temperatures are acceptable . Axillary temperature does not correlate well with pulmonary artery temperature . These results underscore the importance of consistency in method when establishing temperature trends , and of awareness of method when interpreting clinical data 
    Output:
    
The identified studies suggest that in critically ill patients , tympanic and oral thermometry provide , on average , accurate measures of core temperatures within the febrile range and can be recommended for this purpose .