Elsevier

Resuscitation

Volume 144, November 2019, Pages 106-114
Resuscitation

Clinical paper
A randomized trial of oropharyngeal airways to assist stabilization of preterm infants in the delivery room

https://doi.org/10.1016/j.resuscitation.2019.08.035Get rights and content

Abstract

Objective

Positive pressure ventilation (PPV) using a ventilation device and a face mask is recommended for compromised newborn infants in the delivery room (DR). Airway obstruction and face mask leak during PPV may contribute to failure of resuscitation. Using an oropharyngeal airway (OPA) may improve efficacy of mask PPV. To determine whether the use of an OPA with mask PPV in the DR during stabilization of infants <34 weeks’ gestational age, reduces the incidence of airway obstruction.

Intervention and measurements

An international two center unblinded randomized trial. Infants assessed by the clinical team to require PPV, were randomly assigned to receive PPV using a T Piece device with either a soft round face mask alone or in combination with an appropriately sized OPA. Resuscitation protocols were standardized. A hot-wire anemometer flow sensor measured respiratory function during the first five minutes of stabilization. The primary outcome was the incidence of airway obstruction, either complete (no gas flow) or partial (minimal gas flows resulting in expired tidal volumes <2 mL/kg).

Main results

A total of 137 infants were enrolled. Obstructed inflations were more frequently observed in infants stabilized with an OPA (81% vs. 64%; p = 0.03). Partial obstruction was more common in infants stabilized with an OPA (70% vs 54%; p = 0.04). There were no differences in mortality or respiratory outcomes for the whole cohort or in gestational age subgroups.

Conclusions

Airway obstruction is common in preterm infants receiving mask ventilation in the DR. Using an oropharyngeal airway significantly increases the incidence of airway obstruction.

Registered clinical trial

Australian and New Zealand Clinical Trials Register; ACTRN 12612000392864.

Section snippets

Background

Whilst most infants are vigorous immediately after birth, stabilization of newborn infants is one of the most commonly applied medical interventions globally.1, 2, 3 Approximately 10% of newborn infants do not initiate spontaneous respirations after receiving stimulation and require positive pressure ventilation (PPV) in the delivery room (DR).4 International and national neonatal resuscitation guidelines recommend a face mask in combination with a manual ventilation device to provide

Patients and study design

This two center, unblinded randomized controlled study was conducted between December 2011 and December 2014 at the Royal Women’s Hospital (RWH), Melbourne, Australia and between June 2014 and December 2014 at the Royal Alexandra Hospital (RAH), Edmonton, Canada (similarly sized tertiary perinatal centers with an average of 7000 births and 1500 admissions to the neonatal intensive and special care nurseries per year). Infants <34 weeks PMA born at the participating centers were eligible for

Consent

Where possible, parental consent was obtained before birth. If this was not possible, eligible infants were randomized and deferred consent was sought from the parents as soon as possible after birth.20, 21 Deferred consent was obtained to analyze data already collected from the DR and to continue collecting secondary outcome data until primary hospital discharge.

Results

During the study period 149 infants were randomized. Thirteen infants were excluded because they did not receive respiratory support in the DR, no data was obtained due to equipment failure or because their parents did not provide consent (Fig. 1). The remaining 136 infants were followed to hospital discharge or death (67 in the intervention group and 69 in the control group), and included in the analysis. All the infants received the allocated treatment but in 19 (28%) infants allocated to an

Primary outcome

The number of infants with at least one obstructed inflation (either partial obstruction or both), was greater if they were stabilized with the OPA (54; [81%]) compared to standard care in the control group (44 [64%]; p = 0.03). Similarly, the incidence of partial obstruction (VTe <2 mL/kg) was significantly higher in infants stabilized with an OPA compared with the control group (47 (70%) vs 37 (54%); p < 0.04). The incidence of complete obstruction was similar in both groups (p = 0.29).

Secondary outcomes

DR management was similar in both groups with no differences in the rates of endotracheal intubation (Table 3). Only one infant randomized to OPA received cardiac compressions. No differences in neonatal morbidities or length of hospital stay were seen between the two groups. Group comparisons of physiological parameters recorded using the RFM and pulse oximeters in the DR showed no differences (Table 4). The median (IQR) mask leak was similar; 38 (24–55)% and 34 (21–61)% and in intervention

Adverse events of oropharyngeal airway insertion

An attempt was made to insert the OPA in all 67 infants randomized to the intervention, with difficulty experienced in 15 (22%); these were exclusively related to airway opening and inserting the OPA above and behind the tongue. The OPA had to be either down or upsized in these 15 infants. No trauma (bleeding from oropharynx) was seen. Gagging was observed in 6 (9%). During PPV, the OPA was dislodged (pushed out by the movements of the tongue) in 23 (34%) infants. Operators were either unable

Discussion

This is the first randomized trial to investigate oropharyngeal airways as an airway adjunct during neonatal resuscitation. Contrary to our hypothesis, the use of an OPA resulted in significantly more infants receiving obstructed inflations compared to the use of a soft round silicone face mask alone. In keeping with previous reports,5, 10, 11, 12, 24, 25 our findings confirm that mask leak remains very common when preterm infants receive PPV in the DR.

It is very difficult to create a good seal

Conclusions

The use of an oropharyngeal airway as an adjunct to face mask ventilation during the stabilization of very preterm infants causes significantly more obstructed inflations compared to using a soft silicone round face mask alone, and cannot be recommended.

Funding

We would like to thank the public for donation to our funding agencies: Australian National Health and Medical Research Council (NHMRC) Program Grant #606789. JAD and COFK are recipients of a NHMRC Post-Doctoral Fellowship and are supported by the Victorian Government’s Operational Infrastructure Support Program. PGD is recipient of an NHMRC Practitioner Fellowship. GMS is a recipient of the Heart and Stroke Foundation/University of Alberta Professorship of Neonatal Resuscitation and a Heart

Contributor’s statement

C. Omar F. Kamlin conceptualized the study. He recruited patients and performed the analyses. He wrote the first draft of the paper, and contributed to the editing process.

Georg M Schmölzer helped with study conceptualization, recruitment, and contributed to the editing process of the final draft.

Jennifer A. Dawson helped with recruitment, analyses, and contributed to the editing process of the final draft.

Lorraine McGrory helped with recruitment, and contributed to the editing process of the

Financial disclosure

None of the authors have any financial disclosures to declare.

Conflict of interest

None of the authors have any conflicts of interest to declare.

Acknowledgements

The authors thank Ms Connie Wong, Ms Brenda Argus, and Ms Bernice Mills (research nurses), the clinical staff from the neonatal units of The Royal Women's Hospital, Melbourne and Royal Alexandra Hospital, Edmonton, and the parents and infants who participated in this study.

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      Although no difference between the groups were observed, less airway obstruction occurred in our study when compared to previous studies.9,10 One explanation may be that different definitions of obstruction have been used and our definition may have not accounted for the compressive volume of the oropharynx.16,17 There are different explanations for why this study was unable to demonstrate a difference and it is difficult to know which might have contributed.

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      Although the oropharyngeal airway (OPA) has been shown to be effective in children,149 there is no published evidence demonstrating effectiveness in helping maintain the patency of the airway at birth. In a randomised study of 137 preterm infants where gas flow through a mask was measured, obstructed inflations were more common in the OPA group (complete 81% vs. 64%; p = 0.03, partial 70% vs. 54%; p = 0.04).150 However, by helping lift the tongue and preventing it occluding the laryngeal opening, an OPA may facilitate airway support where difficulty is experienced and manoeuvres, like jaw lift, fail to improve ventilation.

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