Case report of congenital methemoglobinemia: an uncommon cause of neonatal cyanosis.

BACKGROUND: Methemoglobinemia can be an acquired or congenital condition. The acquired form occurs from exposure to oxidative agents. Congenital methemoglobinemia is a rare and potentially life-threatening cause of cyanosis in newborns that can be caused by either cytochrome B5 reductase or hemoglobin variants known as Hemoglobin M. CASE PRESENTATION: A term male infant developed cyanosis and hypoxia shortly after birth after an uncomplicated pregnancy, with oxygen saturations persistently 70-80% despite 1.0 FiO2 and respiratory support of CPAP+ 6 cm H2O. Pre- and post-ductal saturations were equal and remained below 85%. Initial radiographic and echography imaging was normal. Capillary blood gas values were reassuring with normal pH and an elevated pO2. Investigations to rule out hemolysis and end-organ dysfunction were within acceptable range. Given the absence of clear cardiac or pulmonary etiology of persistent cyanosis, hematologic causes such as methemoglobinemia were explored. No family history was available at the time of transfer to our institution. Unconjugated hyperbilirubinemia > 5 mg/dL (442 µmol/L) interfered with laboratory equipment measurement, making accurate methemoglobin levels unattainable despite multiple attempts. Initial treatment with methylene blue or ascorbic acid was considered. However, upon arrival of the presumed biological father, a thorough history revealed an extensive paternal family history of neonatal cyanosis due to a rare mutation resulting in a hemoglobin M variant. Given this new information, hematology recommended supportive care as well as further testing to confirm the diagnosis of congenital methemoglobinopathy. Whole genome sequencing revealed a likely pathogenic variation in hemoglobin. The neonate was discharged home at 2 weeks of age on full oral feeds with 0.25 L/min nasal cannula as respiratory support, with close outpatient follow-up. By 5 weeks of age, he was weaned off respiratory support. CONCLUSION: Congenital methemoglobinemia should be considered in the differential diagnosis for newborns with persistent hypoxemia despite normal imaging and laboratory values. Accurate quantification of methemoglobin concentrations is challenging in neonates due to the presence of other substances that absorb light at similar wavelengths, including HbF, bilirubin, and lipids.

Performance and usability of a new mobile application for measuring respiratory rate in young children with acute lower respiratory infections.

OBJECTIVES: Respiratory rate (RR) measurement is critical to diagnosing pneumonia in resource-constrained settings, but accurate RR measurement is challenging. The acute lower respiratory illness treatment and evaluation (ALRITE) mobile phone application (app), designed to help healthcare workers (HCWs) manage pediatric respiratory illnesses, includes a semiautomated RR counter. This study aimed to evaluate the accuracy and usability of the ALRITE RR counter and a commercially available RR counter app, RRate, with a reference standard. METHODS: This was a cross-sectional observational study of HCWs. Participants used both apps to measure the RR of pediatric patients from standardized videos. The reference standard was determined by consensus of a manual 1-min count by two providers. We assessed agreement using Spearman's rank correlation coefficient and constructed Bland-Altman plots to determine bias and limits of agreement. Participants completed a usability survey. RESULTS: Thirty-nine HCWs participated. The agreement between the apps and reference standard (Spearman's coefficient) was 0.83 (95% confidence interval [CI]: 0.78-0.87) for ALRITE and 0.62 (95% CI: 0.52-0.70) for RRate. ALRITE had a bias of -2 breaths/min (lower limit of agreement [LoA] -16 to +12) and RRate had a bias of -0.4 breaths/min (LoA -24 to +23) compared to the reference standard. Both apps had a poorer agreement at higher RRs. Based on usability survey responses, 95% found ALRITE easy to use. CONCLUSIONS: The ALRITE RR counter has acceptable accuracy for counting RR in infants with respiratory distress, appears to be more accurate than a commercially available option, and was user-friendly. The ALRITE RR counter is a promising tool for meriting evaluation in real-world settings.

Utility of Screening Fetal Echocardiogram Following Normal Anatomy Ultrasound for In Vitro Fertilization Pregnancies.

In vitro fertilization (IVF) is associated with a higher incidence of congenital heart disease, resulting in universal screening fetal echocardiograms (F-echo) even when cardiac structures on obstetric scan (OB-scan) are normal. Recent studies suggest that when OB-scan is normal, F-echo may add little benefit and increases cost and anxiety. We aim to determine the utility of screening F-echo in IVF pregnancies with normal cardiac anatomy on prior OB-scan. We conducted a retrospective chart review of IVF pregnancies referred for F-echo at the Seattle Children's Hospital between 2014 and 2020. OB-scan results and subspecialty of interpreting physician (Obstetrics = OB; Maternal Fetal Medicine = MFM; Radiology = Rads), F-echoes, and postnatal outcomes were reviewed. Cardiac anatomy on OB-scans was classified as complete if 4-chamber and outflow-tract views were obtained. Supplemental views (three-vessel and sagittal aortic arch views) on OB-scan were also documented. Of 525 IVF referrals, OB-scan reports were available for review in 411. Normal anatomy was demonstrated in 304 (74%) interpreted by OB (128; 42%), MFM (80; 26%), and Rads (96; 32%). F-echo was normal in 278 (91%). Of the 26 abnormal F-echo, none required intervention (17 muscular and 5 perimembranous ventricular septal defects, and 4 minor valve abnormalities). There was no difference in OB-scan accuracy for identifying normal cardiac anatomy when comparing 4-chamber and outflow-tract views vs. addition of supplemental views (91% vs 92% normal F-echo; p > 0.1). Evaluation of OB-scan accuracy by interpreting physician subspecialty demonstrated normal F-echo in 95%, 85%, and 92% (p = 0.95) as read by OB, MFM, and Rads, respectively. A majority of IVF referrals with normal cardiac anatomy visualized on OB-scan using 4-chamber and outflow-tract views resulted in normal F-echo, regardless of interpreting physician subspecialty or addition of supplemental views. Of the minority with abnormal F-echo, none required intervention. Consideration should be given to the cost/benefit of screening F-echo for the indication of IVF if normal cardiac anatomy is demonstrated on OB-scan.