Intra‐operative temperature monitoring with cutaneous zero‐heat‐ flux‐thermometry in comparison with oesophageal temperature: A prospective study in the paediatric population

Abstract

Background: Maintenance of thermal homeostasis is of crucial importance in the anesthetized pediatric patient. Gold-standard methods for central core temperature measurement are however inappropriately invasive and impractical in daily practice.The SpotOn sensor uses zero-heat-flux thermometry technology and claims to bypass the invasiveness of classical methods and still accurately display central core temperatures. Up to date no formal analysis of this method in children has taken place. Aims:The primary objective was to assess the accuracy in comparison with esophageal temperature; the secondary objective concerned the safety of the SpotOn sensor in the pediatric patients. Methods: Fifty-four children aged 1-12 years with an American Society of Anesthesiology classification I or II scheduled to undergo elective surgical procedures under general anesthesia for a minimum of 30 minutes were included. Exclusion criteria included: fragile forehead skin, procedures impeding proper SpotOn placement, thoracoscopic or gastroesophageal procedures, coagulopathy, hemodynamic instability, or vasoactive medication use. After sevoflurane induction, an esophageal temperature probe was placed in the lower third of the esophagus, and a SpotOn sensor on the lateral forehead. Temperatures were recorded in pairs per 1 minute intervals. Temperatures were subjected to bias analysis with 0.5°C as the a priori established clinical significance cutoff. Results: Bland-Altman analysis revealed the two methods differed on average 0.14°C (95% limits of agreement: −0.39 to 0.66), with 89.5% of the differences being under 0.5°C. No significant differences could be found between the two methods for the established 0.5°C cutoff. Linear regression analysis determined the following linear regression equation: 0.837x + 5.86 (R 2 = 0.738). Lin's concordance correlation coefficient of 0.83 (95% CI: 0.81-0.84). No complications were observed with the use of the SpotOn sensor. Conclusion: SpotOn revealed itself as accurate as an esophageal temperature probe when estimating central core temperatures under ideal conditions and over a narrow range of temperatures. No adverse effects were observed with the use of the SpotOn sensor.

Intraoperative zero-heat-flux thermometry overestimates esophageal temperature by 0.26 °C: an observational study in 100 infants and young children

“…Correctly placed, it lies directly between the left atrium and the descendent aorta and is therefore far away from the potentially cooling airway [20]. Our main finding of a positive bias is in accordance with a previously published study in children by Carvalho et al [16] who found a bias of +0.14 °C with 95% limits of agreement of −0.39 to 0.66 °C. Although our observed bias of +0.26 °C was relatively high, the limits of agreement were tight.…”

“…Second, heads of infants and children consist of thinner skull bones resulting in a closer proximity of the skin to the highly perfused brain [28]. Additionally, if the device uses correction algorithms that are based on the anatomical features of an adult, slight overestimation of temperature in young children might be the consequence that Carvalho et al [16] and we have observed.…”

“…There are some interesting aspects of our study compared to Carvalho et al [16]. In addition to nearly twice as many children being enrolled, we also included a high number of infants.…”

“…An isothermal tunnel corrects the varying temperature of the skin surface [9]. Multiple studies confirmed its clinically acceptable accuracy in adults [9][10][11][12][13][14][15], but there is limited evidence in children [16,17]. A recent meta-analysis revealed substantial differences and a need for further studies in children was formulated [8].…”

Perioperative Hypothermia in Children

“…Ideally, a non-invasive, quick to apply measurement system would be preferable, which could be used in the entire perioperative period [ 17 ]. Presently, several non-invasive thermometers are available, and are gaining more and more interest in children’s medicine [ 17 , 72 , 73 ]. However, to date, neither technique has been evaluated thoroughly in children [ 74 ].…”