High CPAP vs. NIPPV in preterm neonates - A physiological cross-over study

Effect of different CPAP levels on ultrasound-assessed lung aeration and gas exchange in neonates

BACKGROUND

Respiratory distress syndrome (RDS) and transient tachypnoea (TTN) are the two commonest neonatal respiratory disorders. The optimal continuous positive airway pressure (CPAP) to treat them is unknown. We aim to clarify the effect of different CPAP levels on lung aeration and gas exchange in patients with RDS and TTN.

METHODS

Prospective, observational, pragmatic, physiological cohort study. CPAP was sequentially increased from 4 to 6 and 8 cmH2O and backwards, with interposed wash-out periods. Lung aeration was assessed with a validated neonatal lung ultrasound score. Gas exchange was non-invasively evaluated with transcutaneous monitoring. Ultrasound score and PtcO2/FiO2 ratio were the co-primary outcomes. PtcCO2 and other oxygenation metrics were the secondary outcomes.

RESULTS

30 neonates with RDS and 30 with TTN were studied. Each CPAP increment significantly (overall always p < 0.001) improved both lung aeration and oxygenation, but the increase from 6 to 8 cmH2O achieved a small absolute benefit. In RDS patients, the absolute improvements were small and the diagnosis of TTN was significantly associated with greater improvement of lung aeration (β= -1.4 (95%CI: -2.4; -0.3), p = 0.01) and oxygenation (β = 39.6 (95%CI: 4.1; 75.1), p = 0.029). Aeration improved in 16 (53.3%) and 27 (90%) patients in the RDS and TTN groups, respectively (p = 0.034). Lung aeration showed significant hysteresis in TTN patients. Secondary outcomes gave similar results.

CONCLUSIONS

Increasing CPAP from 4 to 8 cmH2O improves ultrasound-assessed lung aeration and oxygenation in RDS and TTN. The absolute improvements are small when CPAP is beyond 6 cmH2O or for RDS patients.

Continuous Positive Airway Pressure versus Nasal Intermittent Positive Pressure Ventilation in Preterm Neonates: What if Mean Airway Pressures Were Equivalent?

Respiratory support for preterm neonates in modern neonatal intensive care units is predominantly with the use of noninvasive interfaces. Continuous positive airway pressure (CPAP) and nasal intermittent positive pressure ventilation (NIPPV) are the prototypical and most commonly utilized forms of noninvasive respiratory support, and each has unique gas flow characteristics. In meta-analyses of clinical trials till date, NIPPV has been shown to likely reduce respiratory failure and need for intubation compared to CPAP. However, a significant limitation of the included studies has been the higher mean airway pressures used during NIPPV. Thus, it is unclear to what extent any benefits seen with NIPPV are due to the cyclic pressure application versus the higher mean airway pressures. In this review, we elaborate on these limitations and summarize the available evidence comparing NIPPV and CPAP at equivalent mean airway pressures. Finally, we call for further studies comparing noninvasive respiratory support modes at equal mean airway pressures. KEY POINTS: · Most current literature on CPAP vs. NIPPV in preterm neonates is confounded by use of higher mean airway pressures during NIPPV.. · In this review, we summarize existing evidence on CPAP vs. NIPPV at equivalent mean airway pressures.. · We call for future research on noninvasive support modes to account for mean airway pressures..

RAM Cannula versus Short Binasal Prongs for Non-invasive Ventilation in Preterm Infants: An Updated Systematic Review and Meta-analysis

OBJECTIVES

To compare the efficacy and safety of RAM cannula with short binasal prongs (SBPs) as nasal interfaces in preterm infants requiring nasal continuous positive airway pressure (nCPAP) or nasal intermittent positive pressure ventilation (NIPPV).

METHODS

The authors searched electronic databases (Medline, Embase, and Web of Science) and trial registries from inception until March 15, 2024, for randomized controlled trials (RCTs) comparing the RAM cannula with SBP for delivering nCPAP/NIPPV. They performed a random-effects meta-analysis using RevMan 5.4 software. The primary outcome was failure of nCPAP/NIPPV. Secondary outcomes included nasal injury, mechanical ventilation, air leaks, and mortality.

RESULTS

Five RCTs (825 participants) were included. There was no significant difference in nCPAP/NIPPV failure (RR: 1.04; 95% CI: 0.58 to 1.87) or the need for invasive mechanical ventilation (RR: 1.23; 95% CI: 0.75 to 2.01) between the RAM cannula and SBP groups (low to very low certainty). Compared with infants in the SBP group, those in the RAM cannula group had a significantly lower incidence of moderate to severe nasal injury [(5 RCTs, 825 participants; RR: 0.34; 95% CI: 0.18 to 0.66); low certainty] and any nasal injury [(RR: 0.44; 95% CI: 0.26 to 0.76; very low certainty)]. There was no significant difference in the other clinical outcomes.

CONCLUSIONS

In comparison to SBP, the RAM cannula may have little to no effect on nCPAP/NIPPV failure, but the evidence is very uncertain. Low-certainty evidence suggests that the use of RAM cannula possibly results in reduction in moderate to severe nasal trauma in preterm infants receiving nCPAP/NIPPV.

Toward Optimal High Continuous Positive Airway Pressure as Postextubation Support in Preterm Neonates: A Retrospective Cohort Study

OBJECTIVE

This study aimed to evaluate whether the initial pressure level on high continuous positive airway pressure (CPAP; ≥9 cm H2O), in relation to preextubation mean airway pressure (Paw), influences short-term clinical outcomes in preterm neonates.

STUDY DESIGN

In this retrospective cohort study, preterm neonates <29 weeks' gestational age (GA) extubated from mean Paw ≥9 cm H2O and to high CPAP (≥9 cm H2O) were classified into "higher level CPAP" (2-3 cm H2O higher than preextubation Paw) and "equivalent CPAP" (-1 to +1 cm H2O in relation to preextubation Paw). Only the first eligible extubation per infant was analyzed. The primary outcome was failure within ≤7 days of extubation, defined as any one or more of (1) need for reintubation, (2) escalation to an alternate noninvasive respiratory support mode, or (3) use of CPAP >preextubation Paw + 3 cm H2O. Secondary outcomes included individual components of the primary outcome, along with other clinical and safety outcomes.

RESULTS

Over a 10-year period (Jan 2011-Dec 2020), 175 infants were extubated from mean Paw >9 cm H2O to high CPAP pressures. Twenty-seven patients (median GA = 24.7, [interquartile range (IQR)]: (24.0-26.4) weeks and chronological age = 31, IQR: [21-40] days) were classified into the "higher level CPAP" group while 148 infants (median GA = 25.4, IQR: [24.6-26.6] weeks and chronological age = 26, IQR: [10-39] days) comprised the "equivalent CPAP" group. There was no difference in the primary outcome (44 vs. 51%; p = 0.51), including postadjustment for confounders (adjusted OR [aOR] = 0.47 [95% confidence interval (CI): 0.17-1.29; p = 0.14]). However, reintubation risk within 7 days was lower with higher level CPAP (7 vs. 37%; p < 0.01), including postadjustment (aOR = 0.07; 95% CI: 0.02-0.35; p < 0.01).

CONCLUSION

In this cohort, use of initial distending CPAP pressures 2 to 3 cm H2O higher than preextubation Paw did not alter the primary outcome of failure but did lower the risk of reintubation. The latter is an interesting hypothesis-generating finding that requires further confirmation.

KEY POINTS

· Use of high CPAP pressures (≥9 cm H2O) is gradually increasing in the care of preterm neonates.. · This study compares higher level versus equivalent CPAP in relation to preextubation Paw.. · The findings demonstrate no difference in failure as defined with use of higher level CPAP pressures..

Noninvasive Ventilation

Systematic Reviews and Randomized clinical trials have shown that the use of noninvasive ventilation (NIV) compared to invasive mechanical ventilation reduces the risk of bronchopulmonary dysplasia and or mortality. Most commonly used NIV modes include nasal continuous positive airway pressure, bi-phasic modes, such as, bi-level positive airway pressure, nasal intermittent positive pressure ventilation, high flow nasal cannula, noninvasive neurally adjusted ventilatory assist, and nasal high frequency ventilation are discussed in this review.

State of the art on neonatal noninvasive respiratory support: How physiological and technological principles explain the clinical outcomes

Noninvasive respiratory support has gained significant popularity in neonatal units because of its potential to reduce lung injury associated with invasive mechanical ventilation. To minimize lung injury, clinicians aim to apply for noninvasive respiratory support as early as possible. However, the physiological background and the technology behind such support modes are not always clear, and many open questions remain regarding the indications of use and clinical outcomes. This narrative review discusses the currently available evidence for various noninvasive respiratory support modes applied in Neonatal Medicine in terms of physiological effects and indications. Reviewed modes include nasal continuous positive airway pressure, nasal high-flow therapy, noninvasive high-frequency oscillatory ventilation, nasal intermittent positive pressure ventilation (NIPPV), synchronized NIPPV and noninvasive neurally adjusted ventilatory assist. To enhance clinicians' awareness of each support mode's strengths and limitations, we summarize technical features related to the functioning mechanisms of devices and the physical properties of the interfaces commonly used for providing noninvasive respiratory support to neonates. We finally address areas of current controversy and suggest possible areas of research for implementing noninvasive respiratory support in neonatal intensive care units.

New developments in neonatal respiratory management

Respiratory distress syndrome (RDS) is the major cause of respiratory failure in preterm infants due to immature lung development and surfactant deficiency. Although the concepts and methods of managing respiratory problems in neonates have changed continuously, determining appropriate respiratory treatment with minimal ventilation-induced lung injury and complications is crucially important. This review summarizes neonatal respiratory therapy's advances and available strategies (i.e., exogenous surfactant therapy, noninvasive ventilation, and different ventilation modes), focusing on RDS management.

Association of delayed initiation of non-invasive respiratory support with pulmonary air leakage in outborn late-preterm and term neonates

The frequency of non-invasive respiratory support use has increased in neonates of all gestational ages with respiratory distress (RD). However, the impact of delayed initiation of non-invasive respiratory support in outborn neonates remains poorly understood. This study aimed to identify the impact of the delayed initiation of non-invasive respiratory support in outborn, late-preterm, and term neonates. Medical records of 277 infants (gestational age of ≥ 35 weeks) who received non-invasive respiratory support as primary respiratory therapy < 24 h of age between 2016 and 2020 were retrospectively reviewed. Factors associated with respiratory adverse outcomes were investigated in 190 outborn neonates. Infants with RD were divided into two groups: mild (fraction of inspired oxygen [FiO₂] ≤ 0.3) and moderate-to-severe RD (FiO₂ > 0.3), depending on their initial oxygen requirements from non-invasive respiratory support. The median time for the initiation of non-invasive respiratory support at a tertiary center was 3.5 (2.2-5.0) h. Male sex, a high oxygen requirement (FiO₂ > 0.3), high CO₂ level, and respiratory distress syndrome were significant factors associated with adverse outcomes. Subgroup analysis revealed that in the moderate-to-severe RD group, delayed commencement of non-invasive respiratory support (≥ 3 h) was significantly associated with pulmonary air leakage (p = 0.033).

CONCLUSION

Our study shows that outborn neonates with moderate-to-severe RD, who were treated with delayed non-invasive respiratory support, were associated with an increased likelihood of pulmonary air leakage. Additional prospective studies are required to establish the optimal timing and methods of non-invasive respiratory support for outborn, late-preterm, and term infants.

WHAT IS KNOWN

• Non-invasive respiratory support is widely used in neonates of all gestational ages. • Little is known on the impact of delayed initiation of non-invasive respiratory support in outborn, late preterm, and term neonates.

WHAT IS NEW

• Male sex, high oxygen requirement (FiO2 >0.3), high initial CO2 level, and respiratory distress syndrome significantly correlated with adverse outcomes. • Outborn late-preterm and term neonates with high oxygen requirement who were treated with delayed non-invasive respiratory support indicated an increased likelihood of pulmonary air leakage.

Novel Ventilation Strategies to Reduce Adverse Pulmonary Outcomes

Extremely preterm infants who must suddenly support their own gas exchange with lungs that are incompletely developed and lacking adequate amount of surfactant and antioxidant defenses are susceptible to lung injury. The decades-long quest to prevent bronchopulmonary dysplasia has had limited success, in part because of increasing survival of more immature infants. The process must begin in the delivery room with gentle assistance in establishing and maintaining adequate lung aeration, followed by noninvasive support and less invasive surfactant administration. Various modalities of invasive and noninvasive support have been used with varying degree of effect and are reviewed in this article.