Extubation Readiness in Preterm Infants: Evaluating the Role of Monitoring Intermittent Hypoxemia

The impact of intermittent hypoxemia on type 1 retinopathy of prematurity in preterm infants

BACKGROUND

Intermittent hypoxemia (IH) may influence retinopathy of prematurity (ROP) development in preterm infants, however, previous studies had mixed results. This study tests the hypothesis that increased IH is associated with Type 1 ROP; a stage beyond which treatment is indicated.

METHODS

IH was quantified by continuously monitoring oxygen saturation (SpO2) using high-resolution pulse oximeters during the first 10 weeks of life. Statistical analyses assessed the relationship and predictive ability of weekly and cumulative IH for Type 1 ROP development.

RESULTS

Most analyses showed no association between IH and Type 1 ROP adjusting for gestational age (GA) and birth weight (BW). However, cumulative IH of longer duration during weeks 5-10, 6-10, and 7-10 were significantly associated with Type 1 ROP adjusting for GA and BW, e.g., the adjusted odds ratio of Type 1 ROP was 2.01 (p = 0.03) for every 3.8 seconds increase in IH duration from week 6-10. IH did not provide statistically significant added predictive ability above GA and BW.

CONCLUSIONS

For most analyses there was no significant association between IH and Type 1 ROP adjusting for GA and BW. However, infants with longer IH duration during the second month of life had higher risk for Type 1 ROP.

IMPACT

The relationship and predictive ability of intermittent hypoxemia (IH) on retinopathy of prematurity (ROP) is controversial. This study shows no significant association between IH events and Type 1 ROP after adjusting for gestational age (GA) and birth weight (BW), except for cumulative IH of longer duration in the second month of life. In this cohort, IH does not provide a statistically significant improvement in ROP prediction over GA and BW. This study is the first to assess the cumulative impact of IH measures on Type 1 ROP. Interventions for reducing IH duration during critical postnatal periods may improve ROP outcomes.

Peri-extubation settings in preterm neonates: a systematic review and meta-analysis

OBJECTIVE

To systematically review: 1) peri-extubation settings; and 2) association between peri-extubation settings and outcomes in preterm neonates.

STUDY DESIGN

In this systematic review, studies were eligible if they reported patient-data on peri-extubation settings (objective 1) and/or evaluated peri-extubation levels in relation to clinical outcomes (objective 2). Data were meta-analyzed when appropriate using random-effects model.

RESULTS

Of 9681 titles, 376 full-texts were reviewed and 101 included. The pooled means of peri-extubation settings were summarized. For objective 2, three experimental studies were identified comparing post-extubation CPAP levels. Meta-analyses revealed lower odds for treatment failure [pooled OR 0.46 (95% CI 0.27-0.76); 3 studies, 255 participants] but not for re-intubation [pooled OR 0.66 (0.22-1.97); 3 studies, 255 participants] with higher vs. lower CPAP.

CONCLUSIONS

Summary of peri-extubation settings may guide clinicians in their own practices. Higher CPAP levels may reduce extubation failure, but more data on peri-extubation settings that optimize outcomes are needed.

Predictors of successful extubation from volume-targeted ventilation in extremely preterm neonates

OBJECTIVE

To identify variables associated with extubation success in extremely preterm neonates extubated from invasive volume-targeted ventilation.

STUDY DESIGN

We retrospectively evaluated 84 neonates ≤28 weeks' gestational age, on their first elective extubation. The primary outcome of successful extubation was defined as non-reintubation within seven days. We used multivariate logistic regression analysis.

RESULTS

We identified 58 (69%) neonates (mean gestational age of 26.5 ± 1.4 weeks, birthweight 921 ± 217 g) who met the primary outcome. Female sex (OR 1.15, 95% CI 1.01-9.10), higher pre-extubation weight (OR 1.29, 95% CI 1.05-1.59), and pH (OR 2.54, 95% CI 1.54-4.19), and lower pre-extubation mean airway pressure (MAP) (OR 0.49, 95% CI 0.33-0.73) were associated with successful extubation.

CONCLUSIONS

In preterm neonates, female sex, higher pre-extubation weight and pH, and lower pre-extubation MAP were predictors of successful extubation from volume-targeted ventilation. Evaluation of these variables will likely assist clinicians in selecting the optimal time for extubation in such vulnerable neonates.

Accuracy of lung and diaphragm ultrasound in predicting successful extubation in extremely preterm infants: A prospective observational study

OBJECTIVE

Chest ultrasound has emerged as a promising tool in predicting extubation readiness in adults and children, yet its utility in preterm infants is lacking. Our aim was to assess the utility of lung ultrasound severity score (LUSS) and diaphragmatic function in predicting extubation readiness in extremely preterm infants.

STUDY DESIGN

In this prospective cohort study, preterm infants < 28 weeks gestational age (GA) who received invasive mechanical ventilation for ≥12 h were enrolled. Chest ultrasound was performed before extubation. The primary outcome was lung ultrasound accuracy for predicting successful extubation at 3 days. Descriptive statistics and logistic regression were done using SPSS version 22.

RESULTS

We enrolled 45 infants, of whom 36 (80%) were successfully extubated. GA and postmenstrual age (PMA) at extubation were significantly higher in the successful group. The LUSS was significantly lower in the successful group compared to failed group (11.9 ± 3.2 vs. 19.1 ± 3.1 p < 0.001). The two groups had no statistically significant difference in diaphragmatic excursion or diaphragmatic thickness fraction. Logistic regression analysis controlling for GA and PMA at extubation showed LUSS was an independent predictor for successful extubation (odd ratio 0.46, 95% confidence interval [0.23-0.9], p = 0.02). The area under the receiver operating characteristic curve was 0.95 (p ˂ 0.001) for LUSS, and a cut-off value of ≥15 had 95% sensitivity and 85% specificity in detecting extubation failure.

CONCLUSION

In extremely preterm infants, lung ultrasound has good accuracy for predicting successful extubation. However, diaphragmatic measurements were not reliable predictors.

Comparison of oxygen supplementation in very preterm infants: Variations of oxygen saturation features and their application to hypoxemic episode based risk stratification

Background

Oxygen supplementation is commonly used to maintain oxygen saturation (SpO₂) levels in preterm infants within target ranges to reduce intermittent hypoxemic (IH) events, which are associated with short- and long-term morbidities. There is not much information available about differences in oxygenation patterns in infants undergoing such supplementations nor their relation to observed IH events. This study aimed to describe oxygenation characteristics during two types of supplementation by studying SpO₂ signal features and assess their performance in hypoxemia risk screening during NICU monitoring.

Subjects and methods

SpO₂ data from 25 infants with gestational age <32 weeks and birthweight <2,000 g who underwent a cross over trial of low-flow nasal cannula (NC) and digitally-set servo-controlled oxygen environment (OE) supplementations was considered in this secondary analysis. Features pertaining to signal distribution, variability and complexity were estimated and analyzed for differences between the supplementations. Univariate and regularized multivariate logistic regression was applied to identify relevant features and develop screening models for infants likely to experience a critically high number of IH per day of observation. Their performance was assessed using area under receiver operating curves (AUROC), accuracy, sensitivity, specificity and F1 scores.

Results

While most SpO₂ measures remained comparable during both supplementations, signal irregularity and complexity were elevated while on OE, pointing to more volatility in oxygen saturation during this supplementation mode. In addition, SpO₂ variability measures exhibited early prognostic value in discriminating infants at higher risk of critically many IH events. Poincare plot variability at lag 1 had AUROC of 0.82, 0.86, 0.89 compared to 0.63, 0.75, 0.81 for the IH number, a clinical parameter at observation times of 30 min, 1 and 2 h, respectively. Multivariate models with two features exhibited validation AUROC > 0.80, F1 score > 0.60 and specificity >0.85 at observation times ≥ 1 h. Finally, we proposed a framework for risk stratification of infants using a cumulative risk score for continuous monitoring.

Conclusion

Analysis of oxygen saturation signal routinely collected in the NICU, may have extensive applications in inferring subtle changes to cardiorespiratory dynamics under various conditions as well as in informing clinical decisions about infant care.