Pharyngeal pressure value using two continuous positive airway pressure devices

Nasal CPAP complications in very low birth weight preterm infants

BACKGROUND

Nasal trauma due to nasal CPAP (nCPAP) use is a commonly reported complication in infants under 1500 g of birth weight and 32 weeks of gestation. With the rise of nCPAP as the gold standard for non-invasive respiratory support, preventive measures should be considered.

OBJECTIVE

To assess the prevalence and risk factors of nasal injury in very low birth weight (VLBW) preterm infants with nCPAP.

METHODS

We retrospectively analyzed neonates hospitalized between 2012 and 2017, with less than 1500 g and 32 weeks of gestational age who received more than 12 hours of nCPAP. Demographic, antenatal and clinical data, along with information regarding respiratory support and nCPAP complications, were collected. We used Fischer's classification to grade nasal trauma.

RESULTS

A total of 135 infants were evaluated. Mean gestational age was 28 weeks (SD 2) and mean birth weight 1072 g (SD 239). Nasal trauma was reported in 65% of patients and it was of stage I, II and III in 49%, 16% and 1% of patients, respectively. The multivariate logistic regression revealed that the risk of trauma was greater in neonates with a longer duration of nCPAP ventilation (OR = 1.098, 95% CI: 1.055-1.142; p < 0.001) and in patients submitted to oxygen therapy (OR = 3.174, 95% CI: 1.014-9.929, p = 0.004). The median of days after nCPAP administration until the onset of an identifiable lesion was 4.

CONCLUSION

Nasal trauma is a frequent complication in VLBW preterm infants using nCPAP for long periods. Preventive measures in patients who are at greater risk of skin breakdown are of major clinical importance for a better outcome.

Respiratory distress syndrome in preterm neonates in the era of precision medicine: A modern critical care-based approach

Respiratory distress syndrome (RDS) was recognized to be caused by primary surfactant deficiency almost 70 years ago and continuous positive airway pressure was introduced approximately 50 years ago. Since then, there have been many developments in neonatology; we know many things but others are still controversial. The more we know, the more questions arise. However, this review aims to indicate what is more needed to understand and how should be the modern approach to RDS in the era of precision medicine. The review is divided between new concepts and new tools. We will explain the interaction between steroids, CPAP and surfactant, as well as the surfactant catabolism and the diagnosis of NARDS; lung ultrasound and new tools to optimize CPAP will also be covered. How these concepts are integrated in the author's personal experience is also illustrated.

Continuous positive airway pressure (CPAP) for respiratory distress in preterm infants

BACKGROUND

Respiratory distress, particularly respiratory distress syndrome (RDS), is the single most important cause of morbidity and mortality in preterm infants. In infants with progressive respiratory insufficiency, intermittent positive pressure ventilation (IPPV) with surfactant has been the usual treatment, but it is invasive, potentially resulting in airway and lung injury. Continuous positive airway pressure (CPAP) has been used for the prevention and treatment of respiratory distress, as well as for the prevention of apnoea, and in weaning from IPPV. Its use in the treatment of RDS might reduce the need for IPPV and its sequelae.

OBJECTIVES

To determine the effect of continuous distending pressure in the form of CPAP on the need for IPPV and associated morbidity in spontaneously breathing preterm infants with respiratory distress.

SEARCH METHODS

We used the standard strategy of Cochrane Neonatal to search CENTRAL (2020, Issue 6); Ovid MEDLINE and Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Daily and Versions; and CINAHL on 30 June 2020. We also searched clinical trials databases and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

All randomised or quasi-randomised trials of preterm infants with respiratory distress were eligible. Interventions were CPAP by mask, nasal prong, nasopharyngeal tube or endotracheal tube, compared with spontaneous breathing with supplemental oxygen as necessary.

DATA COLLECTION AND ANALYSIS

We used standard methods of Cochrane and its Neonatal Review Group, including independent assessment of risk of bias and extraction of data by two review authors. We used the GRADE approach to assess the certainty of evidence. Subgroup analyses were planned on the basis of birth weight (greater than or less than 1000 g or 1500 g), gestational age (groups divided at about 28 weeks and 32 weeks), timing of application (early versus late in the course of respiratory distress), pressure applied (high versus low) and trial setting (tertiary compared with non-tertiary hospitals; high income compared with low income) MAIN RESULTS: We included five studies involving 322 infants; two studies used face mask CPAP, two studies used nasal CPAP and one study used endotracheal CPAP and continuing negative pressure for a small number of less ill babies. For this update, we included one new trial. CPAP was associated with lower risk of treatment failure (death or use of assisted ventilation) (typical risk ratio (RR) 0.64, 95% confidence interval (CI) 0.50 to 0.82; typical risk difference (RD) -0.19, 95% CI -0.28 to -0.09; number needed to treat for an additional beneficial outcome (NNTB) 6, 95% CI 4 to 11; I2 = 50%; 5 studies, 322 infants; very low-certainty evidence), lower use of ventilatory assistance (typical RR 0.72, 95% CI 0.54 to 0.96; typical RD -0.13, 95% CI -0.25 to -0.02; NNTB 8, 95% CI 4 to 50; I2 = 55%; very low-certainty evidence) and lower overall mortality (typical RR 0.53, 95% CI 0.34 to 0.83; typical RD -0.11, 95% CI -0.18 to -0.04; NNTB 9, 95% CI 2 to 13; I2 = 0%; 5 studies, 322 infants; moderate-certainty evidence). CPAP was associated with increased risk of pneumothorax (typical RR 2.48, 95% CI 1.16 to 5.30; typical RD 0.09, 95% CI 0.02 to 0.16; number needed to treat for an additional harmful outcome (NNTH) 11, 95% CI 7 to 50; I2 = 0%; 4 studies, 274 infants; low-certainty evidence). There was no evidence of a difference in bronchopulmonary dysplasia, defined as oxygen dependency at 28 days (RR 1.04, 95% CI 0.35 to 3.13; I2 = 0%; 2 studies, 209 infants; very low-certainty evidence). The trials did not report use of surfactant, intraventricular haemorrhage, retinopathy of prematurity, necrotising enterocolitis and neurodevelopment outcomes in childhood.

AUTHORS' CONCLUSIONS

In preterm infants with respiratory distress, the application of CPAP is associated with reduced respiratory failure, use of mechanical ventilation and mortality and an increased rate of pneumothorax compared to spontaneous breathing with supplemental oxygen as necessary. Three out of five of these trials were conducted in the 1970s. Therefore, the applicability of these results to current practice is unclear. Further studies in resource-poor settings should be considered and research to determine the most appropriate pressure level needs to be considered.

Less invasive surfactant administration: a word of caution

Surfactant is a cornerstone of neonatal critical care, and the presumed less (or minimally) invasive techniques for its administration have been proposed to reduce invasiveness of neonatal critical care interventions. These techniques are generally known as less invasive surfactant administration (LISA) and have quickly gained popularity in some neonatal intensive care units. Despite the increase in the use of LISA, we believe that the pathobiological background supporting its possible clinical benefits is unclear. Similarly, it is unclear whether there are any ignored drawbacks, as LISA has been tested in only a few trials and some physiopathological issues seem to have gone unnoticed. Active research is warranted to fill these knowledge gaps before LISA can be firmly recommended. In this Viewpoint, we provide an in-depth analysis of LISA techniques, based on physiological and pathobiological factors, followed by a critical appraisal of available clinical data, and highlight some possible future research directions.

Assessment of resistance of nasal continuous positive airway pressure interfaces

OBJECTIVE

To compare the resistance of interfaces used for the delivery of nasal continuous positive airway pressure (CPAP) in neonates, as measured by the generated system pressure at fixed gas flows, in an in vitro setting.

DESIGN

Gas flows of 6, 8 and 10 L/min were passed through three sizes of each of a selection of available neonatal nasal CPAP interfaces (Hudson prong, RAM Cannula, Fisher & Paykel prong, Infant Flow prong, Fisher & Paykel mask, Infant Flow mask). The expiratory limb was occluded and pressure differential measured using a calibrated pressure transducer.

RESULTS

Variation in resistance, assessed by mean pressure differential, was seen between CPAP interfaces. Binasal prong interfaces typically had greater resistance at the smallest assessed sizes, and with higher gas flows. However, Infant Flow prongs produced low pressures (<1.5 cmH₂O) at all sizes and gas flows. RAM Cannula had a high resistance, producing a pressure >4.5 cmH₂O at all sizes and gas flows. Both nasal mask interfaces had low resistance at all assessed sizes and gas flows, with recorded pressure <1 cmH₂O in all cases.

CONCLUSIONS

There is considerable variation in measured resistance of available CPAP interfaces at gas flows commonly applied in clinical neonatal care. Use of interfaces with high resistance may result in a greater drop in delivered airway pressure in comparison to set circuit pressure, which may have implications for clinical efficacy. Device manufacturers and clinicians should consider CPAP interface resistance prior to introduction into routine clinical care.

Continuous positive airway pressure delivery during less invasive surfactant administration: a physiologic study

OBJECTIVE

We sought to investigate the pressure delivery during less invasive surfactant administration, as we hypothesize that it might be reduced.

STUDY DESIGN

Physiologic in vitro study in a ventilation lab, using different pressure generators, levels, and leaks in a model of neonatal airways/lung mimicking mechanical characteristics of respiratory distress syndrome. Pressure was measured at the lung and verified in vivo measuring pharyngeal pressure in 19 neonates under same conditions. Data were analyzed using repeated measures-analysis of variance.

RESULTS

Pressure delivery in vitro is significantly and variably reduced during minimally invasive surfactant administration: pressure loss is ≈99% and ≈10-97%, during mouth opening and closure, respectively. Pressure loss seems independent from the type of CPAP and interface. In vivo measurements showed similar pressure drops.

CONCLUSIONS

Pressure transmission during minimally invasive surfactant administration is significantly reduced or totally absent. Pressure drop occurs despite the increased airway resistances and the airflow limitation due to the tracheal catheterization, but is independent from the type of pressure generator and interface.

Use of high noninvasive respiratory support pressures in preterm neonates: a single-center experience

PURPOSE

To describe the incidence, indications and clinical outcomes following high pressures on noninvasive respiratory support (NRS) in preterm neonates.

STUDY DESIGN

Retrospective cohort study of all neonates with BW <1.500 g admitted from July 2012 to June 2014 and placed on high noninvasive respiratory support (NRS), defined as mean airway pressure ≥10 cm H₂O for at least 12 continuous hours using nasal continuous positive airway pressure (NCPAP) and/or nasal high-frequency ventilation (NIHFV). Clinical and physiological outcomes following high NRS were ascertained. Median (IQR) and percentages were used to describe continuous and categorical data, respectively.

RESULTS

There were 131 instances of high NRS use in 70 of 315 eligible infants. Most common indication was post-extubation, observed in 37% (49/131) of high NRS instances. Intubation was avoided in 71% (93/131) of instances in the first 7 days following high NRS initiation. There were no physiological perturbations in heart rate, blood pressure or oxygen requirement. Furthermore, there were no instances of lung hyperinflation, pneumothoraces or spontaneous intestinal perforation following high NRS.

CONCLUSION

The use of high NRS pressure was followed by avoidance of intubation in the majority of cases without adverse effects. Further research on high NRS use including its indications, clinical outcomes and safety profile is warranted.

Continuous distending pressure for respiratory distress in preterm infants

BACKGROUND

Respiratory distress syndrome (RDS) is the single most important cause of morbidity and mortality in preterm infants. In infants with progressive respiratory insufficiency, intermittent positive pressure ventilation (IPPV) with surfactant is the standard treatment for the condition, but it is invasive, potentially resulting in airway and lung injury. Continuous distending pressure (CDP) has been used for the prevention and treatment of RDS, as well as for the prevention of apnoea, and in weaning from IPPV. Its use in the treatment of RDS might reduce the need for IPPV and its sequelae.

OBJECTIVES

To determine the effect of continuous distending pressure (CDP) on the need for IPPV and associated morbidity in spontaneously breathing preterm infants with respiratory distress.Subgroup analyses were planned on the basis of birth weight (> or < 1000 or 1500 g), gestational age (groups divided at about 28 weeks and 32 weeks), methods of application of CDP (i.e. CPAP and CNP), application early versus late in the course of respiratory distress and high versus low pressure CDP and application of CDP in tertiary compared with non-tertiary hospitals, with the need for sensitivity analysis determined by trial quality.At the 2008 update, the objectives were modified to include preterm infants with respiratory failure.

SEARCH METHODS

We used the standard search strategy of the Neonatal Review Group. This included searches of the Oxford Database of Perinatal Trials, the Cochrane Central Register of Controlled Trials (CENTRAL, 2015 Issue 4), MEDLINE (1966 to 30 April 2015) and EMBASE (1980 to 30 April 2015) with no language restriction, as well as controlled-trials.com, clinicaltrials.gov and the International Clinical Trials Registry Platform of the World Health Organization (WHO).

SELECTION CRITERIA

All random or quasi-random trials of preterm infants with respiratory distress were eligible. Interventions were continuous distending pressure including continuous positive airway pressure (CPAP) by mask, nasal prong, nasopharyngeal tube or endotracheal tube, or continuous negative pressure (CNP) via a chamber enclosing the thorax and the lower body, compared with spontaneous breathing with oxygen added as necessary.

DATA COLLECTION AND ANALYSIS

We used standard methods of The Cochrane Collaboration and its Neonatal Review Group, including independent assessment of trial quality and extraction of data by each review author.

MAIN RESULTS

We included six studies involving 355 infants - two using face mask CPAP, two CNP, one nasal CPAP and one both CNP (for less ill babies) and endotracheal CPAP (for sicker babies). For this update, we included no new trials.Continuous distending pressure (CDP) is associated with lower risk of treatment failure (death or use of assisted ventilation) (typical risk ratio (RR) 0.65, 95% confidence interval (CI) 0.52 to 0.81; typical risk difference (RD) -0.20, 95% CI -0.29 to -0.10; number needed to treat for an additional beneficial outcome (NNTB) 5, 95% CI 4 to 10; six studies; 355 infants), lower overall mortality (typical RR 0.52, 95% CI 0.32 to 0.87; typical RD -0.15, 95% CI -0.26 to -0.04; NNTB 7, 95% CI 4 to 25; six studies; 355 infants) and lower mortality in infants with birth weight above 1500 g (typical RR 0.24, 95% CI 0.07 to 0.84; typical RD -0.28, 95% CI -0.48 to -0.08; NNTB 4, 95% CI 2.00 to 13.00; two studies; 60 infants). Use of CDP is associated with increased risk of pneumothorax (typical RR 2.64, 95% CI 1.39 to 5.04; typical RD 0.10, 95% CI 0.04 to 0.17; number needed to treat for an additional harmful outcome (NNTH) 17, 95% CI 17.00 to 25.00; six studies; 355 infants). We found no difference in bronchopulmonary dysplasia (BPD), defined as oxygen dependency at 28 days (three studies, 260 infants), as well as no difference in outcome at nine to 14 years (one study, 37 infants).

AUTHORS' CONCLUSIONS

In preterm infants with respiratory distress, the application of CDP as CPAP or CNP is associated with reduced respiratory failure and mortality and an increased rate of pneumothorax. Four out of six of these trials were done in the 1970s. Therefore, the applicability of these results to current practice is difficult to assess. Further research is required to determine the best mode of administration.

A simple and cheap alternative approach to administering continuous positive airway pressure in resource limited settings

Continuous positive airway pressure (CPAP) is a valuable tool in managing infants requiring respiratory support. This article highlights a simple and economical alternative model to administer nasal CPAP using an infant feeding tube.