Optimal Positioning of Nasopharyngeal Temperature Probes in Infants and Children: A Prospective Cohort Study.

BACKGROUND: The nasopharynx is an easily accessible core-temperature monitoring site, but insufficient or excessive nasopharyngeal probe insertion can underestimate core temperature. Our goal was to estimate optimal nasopharyngeal probe insertion depth as a function of age. METHODS: We enrolled 157 pediatric patients who had noncardiac surgery with endotracheal intubation in 5 groups: (1) newborn to 6 months old, (2) infants 7 months to 1 year old, (3) children 13 to 23 months old, (4) children 2 to 5 years old, and (5) children 6 to 12 years old. A reference esophageal temperature probe was inserted at an appropriate depth based on each patient's height. A nasopharyngeal temperature probe was inserted from the naris at 10 cm in newborn and infants, 15 cm in children aged 1 to 5 years old, and 20 cm in children who were 6 years or older. The study nasopharyngeal probes were withdrawn 1, 2.5, or 2 cm (depending on age) 10 times at 5-minute intervals. Optimal probe insertion distances were defined by limits of agreement (LOAs) between nasopharyngeal and esophageal temperatures <0.5 °C. RESULTS: Optimal nasopharyngeal temperature probe position ranged from 6 to 10 cm in infants up to 6 months old, 7 to 8 cm in infants 7 to 12 months old, 7.5 to 12 cm in children 13 to 23 months old, and 10 to 12 cm in children aged 6 years and older. The 95% LOAs were <0.5 °C for all age categories except the 2- to 5-year-old group where the limits extended from -0.67 °C to 0.52 °C at 9 cm. At the optimal position within each age range, the bias (average nasopharyngeal-to-esophageal temperature difference) was ≤0.1 °C. CONCLUSIONS: Nasopharyngeal thermometers accurately measure core temperature, but only when probes are inserted a proper distance, which varies with age. As with much in pediatrics, nasopharyngeal thermometer insertion depths should be age appropriate.

Use of dexmedetomidine and opioids as the primary anesthetic in infants and young children: A retrospective cohort study.

BACKGROUND: Anesthetic regimens using dexmedetomidine and short-acting opioids have been suggested as potential alternatives to sevoflurane-based anesthesia in children. The primary aim of this study is to compare demographics, intraoperative characteristics, and complications of general anesthetics in which dexmedetomidine and opioids were used without sevoflurane, or in combination with a low sevoflurane concentration, in children 36 months old and younger. The secondary aim is to evaluate intraoperative bispectral index (BIS) values when available in these patients. METHODS: General anesthetics performed between January 1, 2017, and May 1, 2018, in children 2 years and younger who received dexmedetomidine and remifentanil, with or without sevoflurane, were identified. Additional anesthetics performed during this time in children 36 months and younger who received dexmedetomidine and opioids and had BIS monitoring were also identified. Charts were reviewed for demographic and intraoperative variables, including drug administration and hemodynamic data. RESULTS: A total of 244 patients were identified. All but 22 patients received remifentanil. Ninety-two patients received sevoflurane with a mean end-tidal concentration of 0.84% (SD 0.43). Compared to the sevoflurane group, the nonsevoflurane group received more remifentanil (median dose 0.4 µg/kg/min vs 0.2 µg/kg/min, difference of 0.1 µg/kg/min, 95% CI 0.1-0.3, P < .001) and more dexmedetomidine (median dose 0.9 µg/kg/h vs 0.3 µg/kg/h, difference of 0.6 µg/kg/h, 95% CI 0.4-0.8, P < .001), and had a higher mean arterial pressure (median 53 mm Hg vs 42 mm Hg, difference of 11 mm Hg, 95% CI 8.1-14.8, P < .001). Complications between the two groups were comparable. The median percent intraoperative time with BIS reading <60 was 71.6% (95% CI: 63.3%-79.8%). CONCLUSION: Dexmedetomidine and opioids can effectively be used in young children as an alternative total intravenous anesthesia technique with or without <1 minimum alveolar concentration of sevoflurane. Bispectral index monitoring reveals a likely sufficient depth of hypnosis.