Table 1 Final records included in the scoping review based on the inclusion and exclusion criteria (in chronological order)

Viitanen & Kivikoski [27]

Case series

Finland

To assess the thermographical changes in the temperature of the newborns and the comparison with local skin temperature measurements.

18 newborns (immediately after delivery)

AGA Thermovision system Model 652

Tahti et al. [28]

Case series

Finland & Sweden

To record the emitted heat of wide areas of infant’s body and to study the infant’s first reaction to a cold environment.

16 infants directly after delivery (12 healthy full-term infants of normal weight; 2 healthy premature infants with 1800 g and 2200 g body weight; and 2 asphyxiated babies with 1800 g and 2600 g birth weight)

AGA Thermovision system Model 661

Rylander et al. [29]

Case series (with 4 groups)

Sweden

To demonstrate if a cold-induced increase in heat radiation appeared over areas where brown fat should be subcutaneously situated.

43 healthy infants (gestational age 38–44 weeks) checked before the tenth day of life

Group 1, n = 19: infants with a birth weight of 2750 g to 3820 g (in environmental temperature of 24 °C)

Group 2, n = 10: infants with a birth weight of 3240 g to 4020 g (placed in an incubator)

Group 3, n = 7: infants with a birth weight of 1860 g to 2680 g (treated in the same way as Group 2)

Group 4, n = 7: infants with a birth weight of 2980 g to 4370 g (in a water bath of 38 °C)

AGA Thermovision system Model 660

Perlstein et al. [30]

Case series

USA

To investigate if infant age is an important variable to consider in evaluating interscapular skin temperatures in cold-stressed babies.

14 full-term and premature infants (7 of the infants were less than 24 h and 7 more than 5 days old at the time of examination)

No brand name (thermography system Barnes Engineering Co, with an Indium Antimonite sensor 2–4.4 μm. 4 thermograms per second)

Bhatia et al. [31]

Comparative cohort study (follow up of patients’ group sub-sample)

USA

To investigate if TI can be informative in acute and chronic liver disease, particularly on follow-up basis.

Patients group: 62 infants and children from 3 weeks to 17 years of age

Control Group: 32 healthy children from 2 days to 8 years of age

(no specification on how many of them were newborns < 28 days of age)

Follow-up was performed in 28 of the 62 participants (patients group)

AGA Thermovision system (no model description)

Pomerance et al. [15]

Case series

USA

To determine normal anterior and posterior thermograms of the trunk of a newborn; and to investigate whether deep-lying organs can be detected at the surface.

37 newborns (age range not specified for whole group). There was one 2-day-old term, one 3-days old term, one 18 days old pre-term, one 19 days old pre-term etc.

Spectrotherm 2000 Thermographic System

Clark & Stothers [14]

Case series

England

To visualise skin temperature distributions in newborns; and to compare temperatures obtained from thermograms (thermal camera) to skin temperatures measured with a thermometer.

17 newborns 4–13 days old(15 were full-term and 2 were preterm).

AGA Thermovision system Model 680

Oya et al. [32]

Case series

Japan

To measure the extent of non-shivering thermogenesis (NST) in brown adipose tissue of human newborns receiving routine thermal care and to examine the influence of oxygen levels at birth on the initiation of NST.

15 healthy full-term newborns (five minutes after birth)

Thermal Video System 3000 ME, Japan Avionics Co.

Ek et al. [18]

Case series

USA

To investigate the changes in heat loss when radiant warmers were removed and returned to premature infants.

10 premature infants (gestational age 31.4 ± 5.5 weeks), age 15 ± 11.7 days

600 L infrared imaging radiometer (Inframetrics)

Adams et al. [19]

Case series

USA

To test a new method – infrared thermographic calorimetry – against respiratory indirect calorimetry to measure mean body temperature and calculate heat loss.

10 preterm infants (34 ± 23 days)

Inframetrics model 525 infrared camera

Christidis I et al. [17]

Case series (with 4 groups)

Austria

To investigate a surface temperature profile in newborns within the first hour after delivery.

41 newborns (within the first hour after birth)

Group 1, n = 19: infants after normal pregnancy, wrapped into cotton immediately after delivery

Group 2, n = 15: infants examined by paediatrician under a radiant heater

Group 3, n = 4: infants after normal pregnancy who had skin-to-skin contact.

Group 4, n = 3: infants after normal pregnancy, recorded before any intervention.

Thermotracer TH 3100 (NEC San-ei Instruments, Japan)

Saxena & Willital [26]

Case series

Austria

To assess the application of TI to identify pathologies in 1 week to 16 year old children.

(In newborns with abdominal wall defect)

285 patients; 18 newborns (>  1 week old)

Talytherm thermal imager (Rank Taylor Hobson Ltd)

Rice et al. [33]

Case series

USA

To measure the abdominal surface temperature in low birth weight newborns, using thermography, and drawing comparisons between abdominal and thoracic surface temperatures in newborns with and without necrotising enterocolitis (NEC).

13 newborns; 10 newborns had radiographs and were used for comparison. (23–29 gestational weeks; examined during the first month of life)

FLIR SC640 camera

Herry et al. [25]

Case series

Canada

To compare thermograms of the abdomen of healthy newborns and newborns with NEC, to distinguish differences and to investigate if TI is suitable for diagnosing NEC in infants.

59 newborns (48 were had a gestational age of 28.3 ± 2.4 weeks; 11 were of 26.7 ± 1.8 weeks)

No brand name (Infrared camera, uncooled microbolometer focal plane array, 320 × 420 pixels, thermal and spatial sensitivity of 0.05° at 30 °C and 1.3 mrad)

Abbas et al. [34]

Case series

Germany

To use TI to monitor thermal distributions of neonates within the neonatal intensive care unit.

7 preterm newborns (gestational age was a mean of 29 weeks, included in the study directly after birth)

VarioCAM hr. head camera (InfraTech GmbH)

Knobel et al. [8]

Case series

USA

To measure body temperature in infants and examine the relationship between body temperature and symptoms of NEC in infants with low birth weights.

10 low birth newborns (gestational age less than 29 weeks, examined during the first 5 days of life)

FLIR SC640 uncooled infrared camera

Knobel et al. [35]

Case series

USA

To test instrumentation and develop analytic models to use in a larger study to examine developmental trajectories of body temperature and peripheral perfusion from birth in extremely low birth weight (EBLW) infants.

4 newborns, 4 h of birth (< 29 weeks gestational age)

Not mentioned

Heimann et al. [36]

Case series

Germany

To evaluate skin temperature by using different positions with TI in multiple body areas of preterm infants for detailed information about temperature regulation and distribution.

10 preterm infants (12–62 days old)

VarioCam hr-Head (InfraTec GmbH, Germany)

Kurath-Koller et al. [37]

Case series

Austria

To evaluate the safety of laser acupuncture in newborn infants by using a thermal camera to analyse changes in thermal distributions.

20 newborns (23 days old)

FLIR i5 camera

Knobel-Dail et al. [38]

Case series

USA

To explore the utility of TI as a non-invasive method for measuring body temperature in premature infants in an attempt to regionally examine differential temperatures.

Data was collected from 31 infants originally; only 22 had valid thermograms and the first two were used for training (23 to 28 gestational weeks; first 5 days of life)

FLIR SC640 uncooled microbolometer

Barcat et al. [39]

Case series

France

To investigate whether or not skin temperature and vasodilation of the skin affect sleep propensity in neonates.

29 preterm newborns (9 days old)

B400 FLIR Systems infrared camera