Masks and tubes used to support the neonatal airway – how to improve their fit, seal and correct placement

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O'Shea, Joyce E.
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University College Cork
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Despite the many changes in perinatal medicine in the last fifty years, infants still often and unpredictably need assistance with their breathing. Positive pressure delivered through a facemask remains the almost universal initial approach. This is then generally followed by endotracheal intubation if the infant is not responding or if prolonged support is needed. Despite many years of research into mask ventilation, it is still very challenging and leak and airway obstruction remain a problem. The thesis opens with two mask studies that try to solve this problem. The first is a manikin study that compared three different mask holds. It unfortunately found that there was no difference in the mask leak measured using the different holds. It is perhaps reasonable to change holds if the baby isn’t responding as expected. The second study aimed to measure the dimensions of preterm infants’ faces and compare these with the size of the most commonly available face masks. It found that the smallest size of some brands of mask is too large for many preterm infants. Masks of 35mm diameter are suitable for infants <29 weeks PMA or 1000g. Masks of 42 mm diameter are suitable for infants 27-33 weeks PMA or 750-2500g. The thesis then changed focus to neonatal intubation. Intubation is a challenging skill for paediatric trainees to master. In recent years success rates are decreasing. The next studies look at possible ways to change this trend. The first is a Cochrane review that examined if a stylet could improve intubation success. Only one unblended RCT has been performed and found no difference. The most sizable work of the thesis follows and is a RCT that examines if junior trainees intubation success rates are superior if they intubate with a videolaryngoscope. Two hundred and six intubations were randomised to the screen being visible to the supervisor or covered. The success rate when the instructor was able to view the videolaryngoscope screen was 66% (69/104) compared to 41% (42/102) when the screen was covered, (p<0.001), OR 2.81 (95%CI 1.54-5.17). This shows that videolaryngoscopy is a promising tool to help inexperienced trainees become proficient intubators. This study has resulted in videolaryngoscopy becoming a tool commonly used in neonatal intensive cares. The next study looks at recordings of unsuccessful intubations from the RCT. If an attempt is unsuccessful, the intubator and instructor often cannot explain why making it difficult to know what to do differently in the future. The study found that lack of intubation success was most commonly due to failure to recognize midline anatomical structures. Excessive secretions are rarely a factor in elective premeditated and routine suctioning should be discouraged. Better videolaryngoscope blade design may make it easier to direct the tube through the vocal cords. The final work of the thesis is a review that examines devices used during newborn stabilization. Evidence for their use to optimize the thermal, respiratory and cardiovascular management in the delivery room is presented. After completing all this work I think that perhaps it is time to lessen our reliance on facemasks and embrace other airway devices that are showing promise, particularly the laryngeal mask. I feel that universal intubation competency is no longer feasible but universal competency on the use of laryngeal masks probably is. This urgently needs to be addressed in paediatric training programs. Videolaryngoscopy is a promising tool that improves junior intubators’ success rates. To master intubation many intubations are still necessary but the videolaryngoscope allows the slope of the learning curve to steepen. Development is necessary to design scopes of the future that are inexpensive, easily portable and user friendly.
Infant , Neonate , Face masks , Intubation , Videolaryngoscopy
O'Shea, J. E. 2019 Masks and tubes used to support the neonatal airway – how to improve their fit, seal and correct placement. MD Thesis, University College Cork.
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