Presented at the Neonatal Society 2007 Spring Meeting.
De Curtis M1, Calzolari F1, Marciano A1, Cardilli V1, Barba G2
1 Dipartimento di Scienze Ginecologiche, Perinatologia, Puericultura, Università ‘La Sapienza’, Rome, Italy
2 Institute of Food Sciences, CNR, Avellino, Italy
Background: The restriction of mercury has led to the development of other devices for measurement of body temperature. A new thermometer (No Touch Sensor Diagnostic™, Chicco, Italy) that utilizes the infrared technology has been proposed.
Aim: The aim of this study was to validate, in Neonatology, the accuracy and the effectiveness of this not invasive, easy to use and fast to read thermometer.
Materials and methods: A convenience sample of term and preterm infants born and assisted between May and October 2006 at the Dipartimento di Scienze Ginecologiche, Per inatologia e Puericultura, La Sapienza University of Rome, participated in the study. Rectal temperature was taken with a mercury-in-glass thermometer introduced to a depth of 2-3 cm from the anal margin and read after three minutes. Immediately af ter, skin temperature was taken on the central part of forehead, using the thermometer No Touch Sensor Diagnostic™, by the same operator (FC).
In a subgroup of 86 infants, digital skin temperature was measured alternatively by two different operators (FC and AM), each for three times. Written informed consent was obtained by the parents. The work was not supported by funds or other forms of personal institutional financing from the manifacturer.
Statistics: Data are expressed as Mean ± SD or mean and 95% C.I. Concordance rate between the measurements took by the two operators and between the two devices was estimated by correlation analysis. The differences of mercury rectal minus infrared skin temperature were calculated. The limits of agreement between the mercury and digital measurements and those between the digital measurements taken by the two operators were calculated according to Bland and Altman. Statistical signif icance was accepted at P<0.05.
Results: One hundred seven newborn infants with a birth weight of 1927±851 g and a gestational age of 32.7±4.4 weeks, (range 25-41 weeks), at a postnatal age of 15.7±17.3 days (range 1-93 days) were studied. Temperatures ranged from 35.1 to 38.4ºC for rectal temperature and from 35.3 to 38.4ºC for infrared skin temperature . The mean temperature measured by rectal mercury thermometer and infrared skin device were, respectively, 36.62±0.66 and 36.66±0.66ºC (P=0.18). The correlation between the two measurements was statistically significant (r= 0.902, P<0.0001). The difference between rectal temperature and the average of digital temperature measured by the two operators was, on average, – 0.038±0.288ºC (95% C.I.=-0.093, 0.017ºC, range -0.75, 0.72ºC). The limits of agreement ranged from -0.614 to 0.538ºC.
The difference between rectal temperature and the first digital temperature taken immediately after it was quite similar (-0.052±0.315ºC) as well as the limits of agreement (from -0.682 to 0.578ºC).
No statistically significant differences were observed between the infrared skin temperatures measured by the two operators (n=86; 36.63±0.45 vs. 36.62±0.44ºC, P=0.16); the differences between the measurements taken by the two operators ranged from -0.27 to 0.27ºC. Limits of agreement between the temperatures measured in the three different occasions by each operator ranged from -0.20 and 0.20ºC or even narrower.
Conclusion: Infrared skin temperature by No Touch Sensor Diagnostic™ is easy to measure with a low technical error due to operator’s skill. According to our data, the infrared skin measurement can not substitute rectal measurement in all cases; however, the differences between the two measurements, were modest and this, together with the safety of use and absence of discomfort, would encourage the use of infrared skin thermometer in monitoring body temperature in newborns, possibly limiting the use of rectal temperature measurement to a reduced number of cases.