G141(P) Monitoring respiratory function parameters in ventilated infants during inter-hospital emergency neonatal transport

Abstract

Introduction Volume targeted ventilation (VTV) has been shown to decrease the incidence of hypocarbia, air leaks, bronchopulmonary dysplasia (BPD), intraventricular haemorrhage (IVH) and periventricular leukomlacia (PVL). As a result it has now become the predominant mode of ventilation in the NICU. Within the setting of a UK neonatal transport service, ventilation is more commonly non-triggered pressure limited and time cycled. End tidal Carbondioxide (ETCO) monitoring is used as a surrogate marker of ventilation and minute volume and has demonstrable effectiveness. There is a paucity of data however evaluating the use of additional respiratory function parameters, particularly tidal volume and tube leak during inter-hospital emergency neonatal transport. Aim We aimed to assess current use of supplementary respiratory function monitoring within a UK neonatal transport setting. Methods We carried out a telephonic survey of all UK neonatal transport teams to ascertain current practice with regards to monitoring of the following respiratory function parameters in ventilated infants during emergency neonatal transport: PIP, PEEP, MAP, minute volumes, flow, tidal volumes, ETCO and leaks around the ETT. Method of carbon dioxide monitoring was also recorded. Results 21/22 (95%) of UK neonatal transport teams responded to the survey. Currently, during inter-hospital neonatal transport, 9/21(42%) teams monitor tidal volumes and 8/21(38%) teams monitor delivered airway pressures, flow, minute volumes and leaks around ETT. 18/21(85%) teams use ETCO monitoring. Of these, 14/18(77%) use side stream/micro stream and 4/18(23%) use mainstream ETCO monitoring. Conclusions Our survey shows that currently, mechanical ventilation is mainly assessed using heart rate, respiratory rate, oxygen saturations, blood gas, chest rise, auscultation and ETCO monitoring. Hypocapnia is a well-known complication of mechanical ventilation and rates vary significantly between UK neonatal transport teams. Although the vast majority of teams use ETCO monitoring only 40% of services are using a measure of tidal volume. Continuous monitoring of ventilator parameters in an emergency situation and assessment of minute ventilation would allow clinicians to evaluate changes in pulmonary mechanics allowing short-term modifications, potential reductions in key outcome measures such as hypocarbia and possible reduction in medium to long-term adverse respiratory outcomes. Further studies of the potential benefits of enhanced monitoring are required in this high-risk area.