Increased use of heated humidified high flow nasal cannula is associated with longer oxygen requirements

Trends in bronchopulmonary dysplasia and respiratory support among extremely preterm infants in China over a decade

OBJECTIVE

Bronchopulmonary dysplasia (BPD) is one of the most serious complications affecting extremely preterm infants. We aimed to evaluate temporal trends in BPD and administration of respiratory support among extremely preterm infants in China over a decade.

METHODS

This was a retrospective study using data from a multicenter database, which included infants born less than 28 weeks' gestation discharged from 68 tertiary neonatal care centers in China between 2010 and 2019. Changes in rates and severity of BPD, as well as modalities and duration of respiratory support, were evaluated.

RESULTS

Among 4808 eligible infants with gestational age (GA) of 21+6/7  to 27+6/7 weeks and a mean (SD) birth weight of 980 (177) g, no significant change of median GA was found over time. Overall, 780 (16.2%) infants died before 36 weeks' postmenstrual age, 2415 (50.2%) were classified as having no BPD, 917 (19.1%) developed Grade 1 BPD, 578 (12.0%) developed Grade 2 BPD, and 118 (2.5%) developed Grade 3 BPD. The rate of BPD increased from 20.8% in 2010 to 40.7% in 2019 (aRR for trend, 1.081; 95% confidence interval, 1.062-1.099), especially for Grade 1 and Grade 2. Although survival to discharge improved over the decade, the overall survival without BPD did not change during the study period. The use of invasive mechanical ventilation (IMV) remained unchanged. However, the use of noninvasive ventilation (NIV) increased from 71.5% in 2010 to 89.8% in 2019. Moreover, the median duration of NIV increased over time, from 17.0 (4.8, 34.0) days in 2010 to 33.0 (21.0, 44.0) days in 2019, without significant change in the duration of IMV.

CONCLUSIONS

Although survival increased over the decade and respiratory support practices changed significantly between 2010 and 2019 in China, with increased use and duration of NIV, there was an increased rate of BPD and survival without BPD has not improved.

Diaphragm electrical activity during weaning of nasal high-flow therapy in preterm infants

OBJECTIVE

To determine whether electrical activity of the diaphragm (Edi) changes with weaning nasal high-flow (HF) therapy in preterm infants according to a standardised protocol.

DESIGN

Prospective observational cohort study.

SETTING

Neonatal intensive care unit.

PATIENTS

Preterm infants born at <32 weeks gestation, receiving nasal HF as part of routine clinical care.

INTERVENTIONS

Infants recruited to the study had their HF weaned according to set clinical criteria. Edi was measured using a modified gastric feeding tube serially from baseline (pre-wean) to 24-hours post-wean.

MAIN OUTCOME MEASURES

Change in Edi from baseline was measured at four time points up to 24 hours after weaning. Minimum Edi during expiration, maximum Edi during inspiration and amplitude of the Edi signal (Edi_delta) were measured. Clinical parameters (heart rate, respiratory rate and fraction of inspired oxygen) were also recorded.

RESULTS

Forty preterm infants were recruited at a mean corrected gestational age of 31.6 (±2.7) weeks. Data from 156 weaning steps were analysed, 91% of which were successful. Edi did not change significantly from baseline during flow reduction steps, but a significant increase in diaphragm activity was observed when discontinuing HF (median increase in Edi_delta immediately post-discontinuation 1.7 µV (95% CI: 0.6 to 3.0)) and at 24 hours 1.9 µV (95% CI: 0.7 to 3.8)). No significant difference in diaphragm activity was observed between successful and unsuccessful weaning steps.

CONCLUSIONS

A protocolised approach to weaning has a high probability of success. Edi does not change with reducing HF rate, but significantly increases with discontinuation of HF from 2 L/min.

Noninvasive Ventilation in Preterm Infants: Factors Influencing Weaning Decisions and the Role of the Silverman-Andersen Score

The factors influencing weaning of preterm infants from noninvasive ventilation (NIV) are poorly defined and the weaning decisions are often driven by subjective judgement rather than objective measures. To standardize quantification of respiratory effort, the Silverman-Andersen Score (SAS) was included in our nursing routine. We investigated the factors that steer the weaning process and whether the inclusion of the SAS would lead to more stringent weaning. Following SAS implementation, we prospectively evaluated 33 neonates born ≤ 32 + 0 weeks gestational age. Age-, weight- and sex-matched infants born before routine SAS evaluation served as historic control. In 173 of 575 patient days, NIV was not weaned despite little respiratory distress (SAS ≤ 2), mainly due to bradycardias (60% of days without weaning), occurring alone (40%) or in combination with other factors such as apnea/desaturations. In addition, “soft factors” that are harder to grasp impact on weaning decisions, whereas the SAS overall played a minor role. Consequently, ventilation times did not differ between the groups. In conclusion, NIV weaning is influenced by various factors that override the absence of respiratory distress limiting the predictive value of the SAS. An awareness of the factors that influence weaning decisions is important as prolonged use of NIV has been associated with adverse outcome. Guidelines are necessary to standardize NIV weaning practice.

Observational cohort study of changing trends in non-invasive ventilation in very preterm infants and associations with clinical outcomes

OBJECTIVE

To determine the change in non-invasive ventilation (NIV) use over time in infants born at <32 weeks' gestation and the associated clinical outcomes.

STUDY DESIGN

Retrospective cohort study using routinely recorded data from the National Neonatal Research Database of infants born at <32 weeks admitted to neonatal units in England and Wales from 2010 to 2017.

RESULTS

In 56 537 infants, NIV use increased significantly between 2010 and 2017 (continuous positive airway pressure (CPAP) from 68.5% to 80.2% in 2017 and high flow nasal cannula (HFNC) from 14% to 68%, respectively) (p<0.001)). Use of NIV as the initial mode of respiratory support also increased (CPAP, 21.5%-28.0%; HFNC, 1%-7% (p<0.001)).HFNC was used earlier, and for longer, in those who received CPAP or mechanical ventilation. HFNC use was associated with decreased odds of death before discharge (adjusted OR (aOR) 0.19, 95% CI 0.17 to 0.22). Infants receiving CPAP but no HFNC died at an earlier median chronological age: CPAP group, 22 (IQR 10-39) days; HFNC group 40 (20-76) days (p<0.001). Among survivors, HFNC use was associated with increased odds of bronchopulmonary dysplasia (BPD) (aOR 2.98, 95% CI 2.81 to 3.15) and other adverse outcomes.

CONCLUSIONS

NIV use is increasing, particularly as initial respiratory support. HFNC use has increased significantly with a sevenfold increase soon after birth which was associated with higher rates of BPD. As more infants survive with BPD, we need robust clinical evidence, to improve outcomes with the use of NIV as initial and ongoing respiratory support.

Life-threatening bronchopulmonary dysplasia: a British Paediatric Surveillance Unit Study

OBJECTIVES

To assess the minimum incidence of life-threatening bronchopulmonary dysplasia (BPD), defined as need for positive pressure respiratory support or pulmonary vasodilators at 38 weeks corrected gestational age (CGA), in infants born <32 weeks gestation in the UK and Ireland; and to describe patient characteristics, management and outcomes to 1 year.

METHODS

Prospective national surveillance study performed via the British Paediatric Surveillance Unit from June 2017 to July 2018. Data were collected in a series of three questionnaires from notification to 1 year of age.

RESULTS

153 notifications met the case definition, giving a minimum incidence of 13.9 (95% CI: 11.8 to 16.3) per 1000 live births <32 weeks' gestation. Median gestation was 26.1 (IQR 24.6-28) weeks, and birth weight 730 g (IQR 620-910 g). More affected infants were male (95 of 153, 62%; p<0.05). Detailed management and outcome data were provided for 94 infants. Fifteen died at median age 159 days (IQR 105-182) or 49.6 weeks CGA (IQR 43-53). Median age last receiving invasive ventilation was 50 days (IQR 22-98) and total duration of pressure support for surviving infants 103 (IQR 87-134) days. Fifty-seven (60.6%) received postnatal steroids and 22 (23.4%) pulmonary vasodilators. Death (16%) and/or major neurodevelopmental impairment (37.3%) or long-term ventilation (23.4%) were significantly associated with need for invasive ventilation near term and pulmonary hypertension.

CONCLUSIONS

This definition of life-threatening BPD identified an extremely high-risk subgroup, associated with serious morbidity and mortality. Wide variability in management was demonstrated, and future prospective study, particularly in key areas of postnatal steroid use and pulmonary hypertension management, is required.

High-flow nasal cannula as a post-extubation respiratory support strategy in preterm infants: a systematic review and meta-analysis

OBJECTIVE

Perform a systematic review and meta-analysis to assess the effectiveness and complications caused by the use of the high-flow nasal cannula in relation to the post-extubation continuous positive airway pressure system in preterm newborns.

DATA SOURCES

The searches were performed from January 2013 to December 2018 in the PubMed and Embase databases, as well as a manual search on the internet.

DATA SYNTHESIS

Two reviewers independently conducted the search, and a third reviewer resolved questions that arose. Ninety-eight articles from the chosen sources were evaluated, and 66 were discarded because they did not meet the inclusion criteria (inadequate topic, age range, or design, in addition to the duplicates). Fifteen articles were read in full, and five more were discarded due to inadequacy to the topic or design. There were ten articles left for systematic review and four for meta-analysis. The study showed non-inferiority in terms of therapeutic failure of the high-flow nasal cannula in relation to continuous positive airway pressure after extubation of preterm newborns. In the meta-analysis, nasal trauma was significantly lower in patients submitted to the high-flow nasal cannula compared to those using continuous positive airway pressure (p<0.00001).

CONCLUSION

The high-flow nasal cannula is not inferior to continuous positive airway pressure for post-extubation respiratory support in preterm newborns with a gestational age of 32 weeks or less and greater than 28 weeks, in addition to resulting in less nasal trauma.

Prolonged non-invasive ventilation in extremely low birth weight preterm infants is associated with bronchopulmonary dysplasia

AIM

To evaluate the association between the use of nasal continuous positive airway pressure (nCPAP) or nasal intermittent positive pressure ventilation (NIPPV) with the development of bronchopulmonary dysplasia (BPD).

METHODS

This is a single center retrospective cohort analysis of infants born at ≤1000 grams and ≤28 weeks gestation with respiratory distress treated with nCPAP or NIPPV. Groups were compared using Student's t test or chi-square, and associations estimated by logistic regression.

RESULTS

Compared to nCPAP, infants who received NIPPV had a higher incidence of moderate to severe (M-S) BPD (84.2 vs 65.5%, p = 0.044) and death or severe BPD (75.0 vs 47.6%, p = 0.003). Each day on NIPPV was associated with an increased risk of M-S BPD (OR 1.08, p < 0.001) and an increased risk of death or severe BPD (OR 1.03, p = 0.006). After adjusting for days on oxygen, ventilator days, and days on all respiratory support, the odds of developing M-S BPD increased by 4.9% for each additional week on NIPPV (CI 2.1-7.7%, p = .0001).

CONCLUSION

In this cohort, use of NIPPV was associated with an increased risk for developing BPD when compared to infants receiving nCPAP, and each additional day on NIPPV carried significant increased risk for developing BPD.

[Research advances in the methods for weaning from high-frequency oscillatory ventilation in neonates]

Neonatal respiratory failure is a serious clinical illness commonly seen in the neonatal intensive care unit (NICU). Although clinicians want to maximize noninvasive respiratory support, some low-birth-weight preterm infants may require invasive respiratory support from the beginning. As an important respiratory management technique for the treatment of respiratory failure, high-frequency oscillatory ventilation (HFOV) allows gas exchange by rapid delivery at a tidal volume lower than or equal to anatomy death volume. Continuous distending pressure was applied to achieve uniform lung expansion, reduce repeated contraction of lung tissue, and exert a protective effect on lung tissue, and so it is preferred by clinicians and has been widely used in clinical practice. However, no consensus has been reached on the methods for weaning from HFOV. This article reviews the methods for weaning from HFOV, so as to provide help for clinical practice.

Effect of randomization of nasal high flow rate in preterm infants

OBJECTIVE

To assess the effect of nasal high flow (NHF) cannula on end-expiratory level (EEL), continuous distending pressure (CDP) and regional ventilation distribution in preterm infants.

DESIGN

A prospective observational clinical study with randomly applied NHF rates.

PATIENTS AND SETTING

Preterm infants requiring continuous positive airway pressure (CPAP) respiratory support in a Neonatal Intensive Care Unit.

INTERVENTIONS

Infants were measured on randomly applied flow rates at 2, 4, and 6 L/min of NHF and compared with bubble CPAP.

MEASUREMENTS AND RESULTS

Regional ventilation distribution and EEL were measured using electrical impedance tomography (EIT) and respiratory inductance plethysmography (RIP) in 24 preterm infants (31.19 ± 1.17 weeks corrected age). Changes in CDP were measured from the esophagus via the nasogastric tube. Physiological variables were also recorded. There were no differences in ventilation distribution, EEL or CDP between CPAP and NHF (P > .05). However, the physiological variables of FiO₂ (P = .01) and SpO₂ /FiO₂ (P < .01) were improved on CPAP compared with NHF.

CONCLUSION

NHF applied in random order with flow rates between 2 to 6 L/min was equally as good as CPAP in maintaining EEL and ventilation distribution in stable preterm infants. Overall oxygenation was better on CPAP compared to NHF.

Heated Humidified High Flow Nasal Cannula (HHHFNC) is not an effective method for initial treatment of Respiratory Distress Syndrome (RDS) versus nasal intermittent mandatory ventilation (NIMV) and nasal continuous positive airway pressure (NCPAP)

BACKGROUND

Noninvasive respiratory support techniques are widely used to treat respiratory distress syndrome (RDS) in preterm infants, and the effectiveness of these methods should be compared. In the current study, nasal continuous positive airway pressure (NCPAP), nasal intermittent mandatory ventilation (NIMV), and heated humidified high-flow nasal cannula (HHHFNC) were compared.

MATERIALS AND METHODS

In the current bicenter clinical trial, 109 preterm infants with RDS not treated with surfactant were randomly assigned to three groups: NCPAP, NIMV, and HHHFNC. The initial outcomes including the failure of treatment within the first initial 72 h, and the duration of RDS treatment, and the secondary outcomes including the need for intubation, the need for surfactants, the duration of oxygen dependency, the incidence of pneumothorax, the patent ductus arteriosus, intraventricular hemorrhage, length of stay, and mortality were compared among the groups.

RESULTS

The frequency of HHHFNC treatment failure (54.3%) was significantly higher compared with those of NIMV (21.6%) (P < 0.001, hazard ratio [HR] = 9.12, 95% confidence interval [CI] = 2.59 - 32.07) and NCPAP (35.1%) (P = 0.004, HR = 21.25, 95% CI = 2.51-180.08). The median duration of RDS treatment was longer (40 h) in the HHHFNC group, although it was not significantly different from those of NIMV (31.16 h) and NCPAP (38.91 h).

CONCLUSION

Based on the high prevalence of failure of HHHFNC treatment than the other two methods (NCPAP and NIMV), HHHFNC is not recommended as the initial treatment of RDS.