Validity of sidestream endtidal carbon dioxide measurement in critically ill, mechanically ventilated children.

INTRODUCTION: Capnography is used to monitor the endtidal carbon dioxide tension (EtCO2) in exhaled gas. Sidestream capnography has great potential to monitor mechanically ventilated pediatric patients, given the continuous sampling from the endotracheal tube into a gas sensor. However, hemodynamic and respiratory impairments may reduce reliability and validity of sidestream capnography to monitor arterial carbon dioxide tension (PaCO2) in critically ill, mechanically ventilated children. METHODS: In 47 mechanically ventilated pediatric patients (aged 0-14 years, median age 17.2 months), a total of 341 consecutive measurements of PaCO2, EtCO2, respiratory and hemodynamic parameters were performed, and capnogram shape was determined. Validity was assessed with the Bland-Altman limit of agreement (loa), mixed models were used to adjust for variation between patients, and potential confounders were considered with multivariable analyses. RESULTS: EtCO2 (mean 4.50 ± 0.96 kPa) underestimated PaCO2 (mean 5.37 ± 0.87) considerably, resulting in a loa of 0.87 kPa [95% confidence interval (95% CI) -1.03;2.77] and 42.2% percentage error. The association improved significantly b = 0.54 [95 %CI = 0.45;0.64, P < 0.001] when corrected for individual differences. The association between EtCO2 and PaCO2 was not influenced by any of the potential confounders. CONCLUSIONS: Sidestream capnography in mechanically ventilated infants and children seems moderately reliable and valid when corrected for individual differences. Therefore, it could only be used with caution for trend estimation in the individual patient.

[Unexplained cyanosis in two newborns: neonatal methemoglobinemia after maternal perineal infiltration of prilocaine]. / Onbegrepen cyanose bij twee neonaten.

BACKGROUND: Methemoglobinemia is a rare cause of neonatal cyanosis in the newborn. It is considered a medical emergency. Failure of recognition or appropriated treatment could result in serious disease and neonatal death. Neonatal methemoglobinemia can be caused by both hereditary and acquired factors. CASE DESCRIPTION: We present two cases of newborns who developed severe cyanosis a few hours after birth due to methemoglobinemia. This was thought to be related to the local maternal perineal infiltration of prilocaine during childbirth. Though rare, prilocaine is the most potent agent to induce methemoglobinemia compared to other local aneasthetics. After intravenous administration of methylene blue, both newborns fully recovered. CONCLUSION: Neonatal methemoglobinemia is a rare and potentially fatal complication of local anesthetics, particularly prilocaine, administered to the mother during childbirth. Midwives, obstetricians, gynecologists and pediatricians should be aware of this complication. The use of other local anesthetics, including lidocaine, should be considered.

Reference values of exhaled nitric oxide in healthy children 1-5 years using off-line tidal breathing.

Measurement of the fraction of exhaled nitric oxide (FeNO) is a useful test to diagnose and/or monitor eosinophilic airway inflammation. The off-line tidal breathing method is used for measurements in young children, but reference values for preschool children are scarce. The objective of this study was to establish reference values for FeNO in healthy children 1-5 years old. We included 51 healthy children (23 males), mean age 32.5 months, from the general population and measured FeNO, using an off-line tidal breathing method with a chemiluminescence analyzer. The method proved feasible in 100% of the children. Geometric mean FeNO was 7.1 parts per billion (ppb), 95% confidence interval 2.8-11.5 ppb, with the 95th percentile 22.6 ppb. No significant difference was found between boys and girls, and no correlations were observed between FeNO and age, height, or weight. This study demonstrates that the off-line tidal breathing method is feasible to measure FeNO in preschool children and provides reference values of FeNO in healthy children 1-5 years of age.