Capillary blood gas in infants with bronchiolitis: Can end-tidal capnography replace it?

Bias between capnometry and venous carbon dioxide during initial assessment of pediatric emergency department patients: A video-based study

Objective

The bias of capnometry (ETCO2) and venous carbon dioxide (vpCO2) among pediatric emergency department (PED) patients triaged to critical care areas is unknown. We aimed to explore correlations and bias between ETCO2 and vpCO2¸and identify predictors of bias.

Methods

This was an observational, video-based, retrospective study comparing ETCO2 and vpCO2. Pediatric patients with simultaneous ETCO2 and vpCO2 data were included. Our primary aim utilized linear regressions to determine correlations and Bland-Altman analysis to assess bias. Our secondary aim utilized multiple regression to identify clinical covariates contributing to bias. Covariates included age, respiratory rate, heart rate, mean arterial blood pressure, capnometry interface, PED diagnosis, and PED disposition.

Results

A total of 200 PED patients with ETCO2 and vpCO2 data were included. The median (interquartile range [IQR]) ETCO2, vpCO2, and ΔCO2 in mmHg were 38 (32, 46), 49 (41, 61), and 11 (4, 20), respectively. ETCO2 (r = 0.76) and ΔCO2 (r = 0.71) were highly correlated with vpCO2. The mean bias between ETCO2 and vpCO2 was -14.1 mmHg (95% confidence interval [CI], -41.9 -13.7). The bias between ETCO2 and vpCO2 increased at higher values of each measure. ETCO2 sampling interface was the only independent predictor of vpCO2 in our multivariate analysis. Patients requiring bag-valve mask (BVM) ventilation had the highest median bias between ETCO2 and vpCO2 (29 mmHg, IQR 15, 37).

Conclusion

ETCO2 and vpCO2 were highly correlated. However, bias increased at higher levels of both ETCO2 and vpCO2. Among PED patients, ETCO2's ability to approximate vpCO2 diminishes with worsening hypercarbic respiratory failure.

Risk Factors for Severe Respiratory Syncytial Virus Infection in Hospitalized Children

BACKGROUND

RSV often leads to hospitalization, and accurate knowledge of risk factors is crucial.

METHODS

We retrospectively analyzed laboratory-confirmed RSV hospitalizations regarding pregnancy factors, birth status, cigarette smoke exposure, nutrition, social conditions, clinical presentation, and severe disease defined as a need for passive oxygen therapy (pO2Tx), the presence of pneumonia, respiratory failure, intensive care unit (ICU) transfer, and prolonged hospitalization.

RESULTS

A univariate analysis included 594 children (median age 4 months) and revealed a pO2Tx relationship with age ≤ 3 months (OR = 1.56), prematurity (OR = 1.71), being born during RSV season (OR = 1.72), smoke exposure during pregnancy (both parents (OR = 2.41, father (OR = 1.8)), dyspnea (OR = 5.09), and presence of apnea (OR = 5.81). Pneumonia was associated with maternal smoke exposure (OR = 5.01), fever (OR = 3.92), dyspnea (OR = 1.62), history of aspiration (OR = 4.63), and inversely with age ≤ 3 months (OR = 0.45). Respiratory failure was associated with prematurity (OR = 3.13) and apnea (OR = 18.78), while the lower odds were associated with older age (OR = 0.57 per month) and presence of fever (OR = 0.11). ICU transfer was associated with apnea (OR = 17.18), but an inverse association was observed with age (OR = 0.54) and fever (OR = 0.11). A prolonged hospital stay was associated with prematurity (OR = 1.76), low birth weight (OR = 2.89), aspiration (OR = 4.93), and presence of fever (OR = 1.51).

CONCLUSIONS

Age (up to 3 months), prematurity, and presence of apnea are risk factors for a severe RSV course.

Capillary Blood Gas in Children Hospitalized Due to Influenza Predicts the Risk of Lower Respiratory Tract Infection

Background: Influenza may impair respiratory exchange in the case of lower respiratory tract infections (LRTIs). Capillary blood gas (CBG) reflects arterial blood values but is a less invasive method than arterial blood sampling. We aimed to retrospectively verify the usefulness of CBG in pediatric influenza. Material and methods: CBG parameters (pH, pCO2, pO2, SatO2) in laboratory confirmed influenza cases hospitalized in 2013−2020 were verified in terms of LRTI, chest X-ray (CXR) performance, radiologically confirmed pneumonia (CXR + Pneumonia), prolonged hospitalization, and intensive care transfer. A theoretical CBG-based model for CXR performance was created and the odds ratios were compared to the factual CXR performance. Results: Among 409 children (aged 13 days−17 years 3/12, median 31 months), the usefulness of CBG decreased with the age. The SatO2 predicted the LRTI with AUC = 0.74 (95%CI: 0.62−0.86), AUC = 0.71 (0.61−0.82), and AUC = 0.602 (0.502−0.702) in children aged <6 months old (mo), 6−23 mo, 24−59 mo, respectively, while pO2 revealed AUC = 0.73 (0.6−0.85), AUC = 0.67 (0.56−0.78), and AUC = 0.601 (0.501−0.702), respectively. The pCO2 predicted the LRTI most precisely in children <6 months with AUC = 0.75 (0.63−0.87), yet not in older children. A high negative predictive value for CXR + Pneumonia was seen for SatO2 < 6 mo (96.7%), SatO2 6−23 mo (89.6%), pO2 < 6 mo (94.3%), pO2 6−23 mo (88.9%). The use of a CBG-driven CXR protocol (based on SatO2 and pO2) would decrease the odds of an unnecessary CXR in children <2 years old (yo) by 84.15% (74.5−90.14%) and 86.15% (66.46−94.28%), respectively. SatO2 and pO2 also predicted a prolonged hospitalization <6 mo AUC = 0.71 (0.59−0.83) and AUC = 0.73 (0.61−0.84), respectively, and in 6−23 mo AUC = 0.66 (0.54−0.78) and AUC = 0.63 (0.52−0.75), respectively. Conclusions: The CBG is useful mainly in children under two years, predicts the risk of LRTI, and can help exclude the risk of CXR + pneumonia. Children under six months of age represent the group that would benefit the most from CBG. A CBG-based protocol for the performance of CXR could significantly decrease the number of unnecessary CXRs.

Capillary Blood Gas Predicts Risk of Intensive Care in Children with Bronchiolitis

Background: Bronchiolitis may result in respiratory failure diagnosed with arterial blood gas (ABG). ABG is not routinely performed in general paediatric wards but is closely reflected by capillary blood gas (CBG). We sought to assess the usefulness of CBG results in prediction of intensive care unit (ICU) transfer, antibiotic treatment, and length of stay in children hospitalized due to bronchiolitis. Methods: The optimal cutoff values were estimated with an ROC analysis, while a multiple regression model calculated the odds of an ICU transfer, prolonged hospitalization, and antibiotic treatment related with hypercapnia (pCO₂ ≥ 45 mmHg) and acidosis (pH ≤ 7.35). The correlation between the CBG (pH, pCO₂, and SatO₂) and the clinical/laboratory parameters (breath rate, heart rate, pulse oximetry, white blood cells, CRP, and procalcitonin) was calculated. Results: The CBG was performed in 485 children aged 8 days–22 months (median 2 months). The pCO₂ was significantly higher in ICU transferred patients (median 44.8 mmHg vs. 36.2 mmHg, p < 0.01), and showed AUC = 0.773, (95% CI: 0.638–0.907, p < 0.01) for ICU transfer (67% sensitivity, 82% specificity, 10.8% positive and 98.7% negative predictive value at cutoff 41.8 mmHg). Hypercapnia (OR = 6.63, 95% CI: 2.15–20.46, p < 0.01) and acidosis (OR = 5.01, 95% CI: 1.26–19.9, p = 0.022) predicted the ICU transfer independently. The CBG parameters were not related to prolonged hospitalization or antibiotic treatment, and showed only a weak and clinically irrelevant correlation with other laboratory and clinical parameters. Conclusions: Acidosis and hypercapnia indicate patients at risk of an ICU transfer, and the pCO₂ levels (including values lower than hypercapnia) seem to be a promising marker in ICU risk assessment.