Smaller facemasks for positive pressure ventilation in preterm infants: A randomised trial

Effect of interface dead space on the time taken to achieve changes in set FiO2 during T-piece ventilation: is face mask the optimal interface for neonatal stabilisation?

BACKGROUND

T-piece is recommended for respiratory support during neonatal stabilisation. Bench studies have shown a delay >30 s in achieving changes in fraction of inspired oxygen (FiO2) at the airway when using the T-piece. Using a face mask adds dead space (DS) to the patient airway. We hypothesised that adding face mask to T-piece systems adversely affects the time required for a change in FiO2 to reach the patient.

METHODS

Neopuff (Fisher and Paykel, Auckland, New Zealand) and rPAP (Inspiration Healthcare, Croydon, UK) were used to ventilate a test lung. DS equivalent to neonatal face masks was added between the T-piece and test lung. Additionally, rPAP was tested with nasal prongs. Time course for change in FiO2 to be achieved at the airway was measured for increase (0.3-0.6) and decrease (1.0-0.5) in FiO2. Primary outcome was time to reach FiO2+/-0.05 of the set target. One-way analysis of variance was used to compare mean time to reach the primary outcome between different DS volumes.

RESULTS

In all experiments, the mean time to reach the primary outcome was significantly shorter for rPAP with prongs compared with Neopuff and rPAP with face mask DS (p<0.001). The largest observed difference occurred when testing a decrease in FiO2 with 10 mL tidal volume (TV) without leakage (18.3 s for rPAP with prongs vs 153.4 s for Neopuff with face mask DS). The shortest observed time was 13.3 s when increasing FiO2 with 10 mL TV with prongs with leakage and the longest time was 172.7 s when decreasing FiO2 with 4 mL TV and added face mask DS without leak.

CONCLUSION

There was a delay in achieving changes in oxygen delivery at the airway during simulated ventilation attributable to the mask volume. This delay was greatly reduced when using nasal prongs as an interface. This should be examined in clinical trials.

Facial growth dynamics dictate optimal facemask fitting during the first year of life

AIM

The aim of this study is to prevent mask leak during ventilation in infant emergencies, appropriate facemask fitting is essential. Therefore, we investigated facial profiles during the first year of life and their correlation with the correct sizing of masks.

METHODS

This is a post hoc subgroup analysis of 32 healthy term infants, based on a prospective observational study performed from September 2018 to December 2019 in Tuebingen, Germany. In 3-monthly intervals, facial aspects were measured based on anatomical landmarks in three-dimensional frontal photographs to describe their changes across the first year of life. All infants were awake and breathing spontaneously; none required any anaesthesia.

RESULTS

In 130 3D images, mean distance between nasion and gnathion was 54 mm (3.3) measured at birth and 70 mm (3.5) at age 12 months. Gompertz models showed relevant growth-related changes in the facial profile in vertical but not horizontal direction. Vertical growth occurred mainly in the first 6 months. Boys and girls differed by an average of about 2 mm (boys >girls).

CONCLUSION

Based on our findings, it should now be verified whether the 50 mm facemasks are suitable for infants from birth to 2 months of age, respectively, the 60 mm version for infants aged three to 12 months.

Positive Pressure Ventilation in Preterm Infants in the Delivery Room: A Review of Current Practices, Challenges, and Emerging Technologies

BACKGROUND

A major proportion of preterm neonates require positive pressure ventilation (PPV) immediately after delivery. PPV may be administered through a face mask (FM) or nasal prongs. Current literature indicates that either of these are associated with similar outcomes.

SUMMARY

Nonetheless, FM remains the most utilized and the best choice. However, most available FM sizes are too large for extremely preterm infants, which leads to mask leak and ineffective PPV. Challenges to providing effective PPV include poor respiratory drive, complaint chest wall, weak thoracic muscle, delayed liquid clearance, and surfactant deficiency in preterm infants. Mask leak, airway obstruction, poor technique, and inappropriate size are correctable causes of ineffective PPV. Visual assessment of chest rise is often used to assess the efficacy of PPV. However, its accuracy is debatable. Though end tidal CO2 may adjudge the effectiveness of PPV, clinical studies are limited. The compliance of a preterm lung is highly dynamic. The inflating pressure set on T-piece is constant throughout the resuscitation, but the lung volume and dynamics changes with every breath. This leads to huge fluctuations of tidal volume delivery and can trigger inflammatory cascade in preterm infants leading to brain and lung injury. Respiratory function monitoring in the delivery room has potential for guiding and optimizing delivery room resuscitation. This is, however, limited by high costs, complex information that is difficult to interpret during resuscitation, and absence of clinical trials.

KEY MESSAGES

This review summarizes the existing literature on PPV in preterm infants, the various aspects related to it such as the pathophysiology, interfaces, devices utilized to deliver it, appropriate technique, emerging technologies, and future directions.

Respiratory function monitoring during neonatal resuscitation: A systematic review

Aim

Positive pressure ventilation via a facemask is critical in neonatal resuscitation, but frequently results in mask leak, obstruction, and inadequate respiratory support. This systematic review aimed to determine whether the display of respiratory function monitoring improved resuscitation or clinical outcomes.

Methods

Randomized controlled trials comparing outcomes when respiratory function monitoring was displayed versus not displayed for newborns requiring positive pressure ventilation at birth were selected and from databases (last search August 2022), and assessed for risk of bias using Cochrane Risk of Bias Tools for randomized control trials. The study was registered in the Prospective Register of Systematic Reviews. Grading of Recommendations, Assessment, Development and Evaluations was used to assess the certainty of evidence. Treatment recommendations were approved by the Neonatal Life Support Task Force of the International Liaison Committee on Resuscitation. Results reported primary and secondary outcomes and included resuscitation and clinical outcomes.

Results

Of 2294 unique articles assessed for eligibility, three randomized controlled trials were included (observational studies excluded) (n = 443 patients). For predefined resuscitation and clinical outcomes, these studies either did not report the primary outcome (time to heart rate ≥ 100 bpm from birth), had differing reporting methods (achieving desired tidal volumes, significant mask leak) or did not find significant differences (intubation rate, air leaks, death before hospital discharge, severe intraventricular hemorrhage, chronic lung disease). Limitations included limited sample size for critical outcomes, inconsistent definitions amongst studies and unreported long-term outcomes.

Conclusion

Although respiratory function monitoring has been utilized in clinical care, there is currently insufficient evidence to suggest its benefit for newborn infants receiving respiratory support for resuscitation at birth.

Registration

PROSPERO CRD42021278169 (registered November 27, 2021).

Funding

The International Liaison Committee on Resuscitation provided support that included access to software platforms and teleconferencing.

Respiratory function monitoring to improve the outcomes following neonatal resuscitation: a systematic review and meta-analysis

IMPORTANCE

Animal and observational human studies report that delivery of excessive tidal volume (V_T) at birth is associated with lung and brain injury. Using a respiratory function monitor (RFM) to guide V_T delivery might reduce injury and improve outcomes.

OBJECTIVE

To determine whether use of an RFM in addition to clinical assessment versus clinical assessment alone during mask ventilation in the delivery room reduces in-hospital mortality and morbidity of infants <37 weeks' gestation.

STUDY SELECTION

Randomised controlled trials (RCTs) comparing RFM in addition to clinical assessment versus clinical assessment alone during mask ventilation in the delivery room of infants born <37 weeks' gestation.

DATA ANALYSIS

Risk of bias was assessed using Covidence Collaboration tool and pooled into a meta-analysis using a random-effects model. The primary outcome was death prior to discharge.

MAIN OUTCOME

Death before hospital discharge.

RESULTS

Three RCTs enrolling 443 infants were combined in a meta-analysis. The pooled analysis showed no difference in rates of death before discharge with an RFM versus no RFM, relative risk (RR) 95% (CI) 0.98 (0.64 to 1.48). The pooled analysis suggested a significant reduction for brain injury (a combination of intraventricular haemorrhage and periventricular leucomalacia) (RR 0.65 (0.48 to 0.89), p=0.006) and for intraventricular haemorrhage (RR 0.69 (0.50 to 0.96), p=0.03) in infants receiving positive pressure ventilation with an RFM versus no RFM.

CONCLUSION

In infants <37 weeks, an RFM in addition to clinical assessment compared with clinical assessment during mask ventilation resulted in similar in-hospital mortality, significant reduction for any brain injury and intraventricular haemorrhage. Further trials are required to determine whether RFMs should be routinely available for neonatal resuscitation.

Safe emergency neonatal airway management: current challenges and potential approaches

This review examines the airway adjuncts currently used to acutely manage the neonatal airway. It describes the challenges encountered with facemask ventilation and intubation. Evidence is presented on how to optimise intubation safety and success rates with the use of videolaryngoscopy and attention to the intubation environment. The supraglottic airway (laryngeal mask airway) is emerging as a promising neonatal airway adjunct. It can be used effectively with little training to provide a viable alternative to facemask ventilation and intubation in neonatal resuscitation and be used as an alternative conduit for the administration of surfactant.

Tidal volumes and pressures delivered by the NeoPuff T-piece resuscitator during resuscitation of term newborns

AIM

T-piece resuscitators are commonly used for respiratory support during newborn resuscitation. This study aimed to describe delivered pressures and tidal volumes when resuscitating term newborns immediately after birth, using the NeoPuff T-piece resuscitator.

METHOD

Observational study from June 2019 through March 2021 at Stavanger University Hospital, Norway, including term newborns ventilated with a T-piece resuscitator after birth, with consent to participate. Ventilation parameters of the first 100 inflations from each newborn were recorded by respiration monitors and divided into an early (inflation 1-20) and a late (inflation 21-100) phase.

RESULTS

Of the 7730 newborns born, 232 term newborns received positive pressure ventilation. Of these, 129 newborns were included. In the early and the late phase, the median (interquartile range) peak inflating pressure was 30 (28-31) and 30 (27-31) mbar, and tidal volume was 4.5 (1.6-7.8) and 5.7 (2.2-9.8) ml/kg, respectively. Increased inflation times were associated with an increase in volume before plateauing at an inflation time of 0.41 s in the early phase and 0.50 s in the late phase. Inflation rates exceeding 32 per minute in the early phase and 41 per minute in the late phase were associated with lower tidal volumes.

CONCLUSION

There was a substantial variation in tidal volumes despite a relatively stable peak inflating pressure. Delivered tidal volumes were at the lower end of the recommended range. Our results indicate that an inflation time of approximately 0.5 s and rates around 30-40 per minute are associated with the highest delivered tidal volumes.

Time to desaturation in preterm infants undergoing endotracheal intubation

BACKGROUND

Neonatal endotracheal intubation is often associated with physiological instability. The Neonatal Resuscitation Program recommends a time-based limit (30 s) for intubation attempts in the delivery room, but there are limited physiological data to support recommendations in the neonatal intensive care unit (NICU). We aimed to determine the time to desaturation after ceasing spontaneous or assisted breathing in preterm infants undergoing elective endotracheal intubation in the NICU.

METHODS

Observational study at The Royal Women's Hospital, Melbourne. A secondary analysis was performed of video recordings of neonates ≤32 weeks' postmenstrual age undergoing elective intubation. Infants received premedication including atropine, a sedative and muscle relaxant. Apnoeic oxygenation time (AOT) was defined as the time from the last positive pressure or spontaneous breath until desaturation (SpO₂ <90%).

RESULTS

Seventy-eight infants were included. The median (IQR) gestational age at birth was 27 (26-29) weeks and birth weight 946 (773-1216) g. All but five neonates desaturated to SpO₂ <90% (73/78, 94%). The median (IQR) AOT was 22 (14-32) s. The median (IQR) time from ceasing positive pressure ventilation to desaturation <80% was 35 (24-44) s and to desaturation <60% was 56 (42-68) s. No episodes of bradycardia were seen.

CONCLUSIONS

This is the first study to report AOT in preterm infants. During intubation of preterm infants in the NICU, desaturation occurs quickly after cessation of positive pressure ventilation. These data are important for the development of clinical guidelines for neonatal intubation.

TRIAL REGISTRATION NUMBER

ACTRN12614000709640.

Eligibility Criteria and Representativeness of Randomized Clinical Trials That Include Infants Born Extremely Premature: A Systematic Review

OBJECTIVE

To assess the eligibility criteria and trial characteristics among contemporary (2010-2019) randomized clinical trials (RCTs) that included infants born extremely preterm (<28 weeks of gestation) and to evaluate whether eligibility criteria result in underrepresentation of high-risk subgroups (eg, infants born at <24 weeks of gestation).

STUDY DESIGN

PubMed and Scopus were searched January 1, 2010, to December 31, 2019, with no language restrictions. RCTs with mean or median gestational ages at birth of <28 weeks of gestation were included. The study followed the PRISMA guidelines; outcomes were registered prospectively. Data extraction was performed independently by multiple observers. Study quality was evaluated using a modified Jadad scale.

RESULTS

Among RCTs (n = 201), 32 552 infants were included. Study participant characteristics, interventions, and outcomes were highly variable. A total of 1603 eligibility criteria were identified; rationales were provided for 18.8% (n = 301) of criteria. Fifty-five RCTs (27.4%) included infants <24 weeks of gestation; 454 (1.4%) infants were identified as <24 weeks of gestation.

CONCLUSIONS

The present study identifies sources of variability across RCTs that included infants born extremely preterm and reinforces the critical need for consistent and transparent policies governing eligibility criteria.

Observational study of parental opinion of deferred consent for neonatal research

OBJECTIVE

To evaluate the opinions of parents of newborns following their infant's enrolment into a neonatal research study through the process of deferred consent.

DESIGN

Mixed-methods, observational study, interviewing 100 parents recently approached for deferred consent.

SETTING

Tertiary-level neonatal intensive care unit, Melbourne, Australia.

RESULTS

All 100 parents interviewed had consented to the study/studies using deferred consent; 62% had also experienced a prospective neonatal consent process. Eighty-nine per cent were 'satisfied' with the deferred consent process. The most common reason given for consenting was 'to help future babies'. Negative comments regarding deferred consent mostly related to the timing of the consent approach, and some related to a perceived loss of parental rights. A deferred approach was preferred by 51%, 24% preferred a prospective approach and 25% were unsure. Those who thought prospective consent would not have been preferable cited impaired decision-making, inappropriate timing of an approach before birth and their preference for removal of the decision-making burden via deferred consent. Seventy-seven per cent thought they would have given the same response if approached prospectively; those who would have declined reported that a prospective approach under stressful conditions was unwelcome and too overwhelming.

CONCLUSION

In our sample, 89% of parents of infants enrolled in neonatal research using deferred consent considered it acceptable and half would not have preferred prospective consent. The ability to make a more considered decision under less stressful circumstances was key to the acceptability of deferred consent.

How does the BAPM Framework for Practice on Perinatal Management of Extreme Preterm Birth Before 27 Weeks of Gestation impact delivery of Newborn Life Support? A Resuscitation Council UK response

In October 2019, the British Association of Perinatal Medicine (BAPM) published a Framework1 and associated infographic2 for 'Practice on Perinatal Management of Extreme Preterm Birth Before 27 Weeks of Gestation' This outlined an approach, based on data from the UK and abroad, to assist clinicians in decision-making relating to perinatal care at ≤26⁺⁶ weeks gestation. Many frontline providers of delivery room care of extremely preterm infants will have completed a Resuscitation Council UK (RCUK) Newborn Life Support or Advanced Resuscitation of the Newborn Infant course. This RCUK response to the BAPM Framework highlights how this might impact on their approach.

Do commonly available round facemasks fit near-term and term infants?

OBJECTIVE

With inappropriately large facemasks, it is more difficult to create a seal on the face, potentially leading to ineffective ventilation during neonatal stabilisation. We investigated whether commonly available round facemasks are of appropriate size by measuring facial dimensions in near-term and term infants using two-dimensional (2D) and three-dimensional (3D) images.

DESIGN

Prospective single-centre observational study.

SETTING

Infants born in our centre at 34-41 weeks' gestation were eligible.

INTERVENTION

Patients were photographed with 2D and 3D technique.

MAIN OUTCOME MEASURES

Distances between nasion and gnathion were measured and compared with the outer diameter of various round facemasks.

METHODS

2D and 3D images were performed using standard equipment. Correlations between gestational age and the above-mentioned distances were assessed using Pearson's r.

RESULTS

Images were taken from 102 infants with a mean (SD) gestational age of 37.9 (2.3) weeks. Mean distance between nasion and gnathion was 46.9 mm (5.1) in 2D and 49.9 mm (4.1) in 3D images, that is, on average 3 mm smaller in 2D than with 3D (p<0.01). Based on these measurements, round facemasks with an external diameter of 50 mm seemed fitting for most (61%) term infants and 42 mm masks for most (72%) near-term infants (GA 34-36 weeks).

CONCLUSIONS

Round facemasks with an external diameter of 60 mm are too large for almost all newborn infants, while 42/50 mm round facemasks are well fitting. Important anatomical structures were only visible using 3D images.

CLINICAL TRIAL REGISTRATION NUMBER

NCT03369028.

Paediatric exhaled CO2 detector causes leaks

OBJECTIVE

To assess leakage caused by the Pedi-Cap.

METHODS

Bench test I: Pedi-Caps were connected between the Neopuff and a test lung and placed underwater to detect the leak. Bench test II: the disposable Avea VarFlex Flow Transducer measured the leak. Retrospective analysis: recordings of intubations in the delivery room were analysed.

RESULTS

The (rippled) male end of the Pedi-Cap is the origin of the leak. In bench test I, 32% of the Pedi-Caps caused inevitable extensive leaks and 34% caused leaks that diminished after sealing the end. In bench test II (n=44) and the retrospective analysis (n=17), the flow transducer measured 22% (18-60) and 39% (8-82) leakage, respectively. Leakage decreased after removal of the Pedi-Cap (before vs after; 17% (7-75) vs 4% (2-10), p=0.004).

CONCLUSION

The Pedi-Cap causes the leak which can compromise respiratory support. We recommend to remove the Pedi-Cap directly after change of colour and to be cautious when using the device as evaluation tool.

Deferred consent for delivery room studies: the providers' perspective

OBJECTIVE

To gain insight into neonatal care providers' perceptions of deferred consent for delivery room (DR) studies in actual scenarios.

METHODS

We conducted semistructured interviews with 46 neonatal intensive care unit (NICU) staff members of the Leiden University Medical Center (the Netherlands) and the Hospital of the University of Pennsylvania (USA). At the time interviews were conducted, both NICUs conducted the same DR studies, but differed in their consent approaches. Interviews were audio-recorded, transcribed and analysed using the qualitative data analysis software Atlas.ti V.7.0.

RESULTS

Although providers reported to regard the prospective consent approach as the most preferable consent approach, they acknowledged that a deferred consent approach is needed for high-quality DR management. However, providers reported concerns about parental autonomy, approaching parents for consent and ethical review of study protocols that include a deferred consent approach. Providers furthermore differed in perceived appropriateness of a deferred consent approach for the studies that were being conducted at their NICUs. Providers with first-hand experience with deferred consent reported positive experiences that they attributed to appropriate communication and timing of approaching parents for consent.

CONCLUSION

Insight into providers' perceptions of deferred consent for DR studies in actual scenarios suggests that a deferred consent approach is considered acceptable, but that actual usage of the approach for DR studies can be improved on.

Enhanced monitoring during neonatal resuscitation

Immediately after birth through spontaneous breaths, infants' clear lung liquid replacing it with air, and gradually establishing a functional residual capacity to achieve gas exchange. Most infants start breathing independently after birth and ~3% of infants who require positive pressure ventilation. When newborns fail to start breathing the current neonatal resuscitation guidelines recommend initiatingpositive pressure ventilationusing a face mask and a ventilation device. Adequate ventilation is the cornerstone of successful neonatal resuscitation; therefore, it is mandatory that anybody involved in neonatal resuscitation is trained in mask ventilation techniques. One of the main problems with mask ventilation is that it is very subjective with direct feedback lacking and not uncommonly, the resuscitator does not realise that their technique is unsatisfactory. Many studies have shown that monitoring tidal volume and leak around the mask or endotracheal tube enables the resuscitator to identify the problem and adjust their technique to reduce the leak and deliver and appropriate tidal volume. This chapter discusses the currently available monitoring devices used during stabilization/resuscitation in the delivery room.