Optimising neonatal endotracheal intubation and face mask ventilation

Background: Endotracheal intubation is commonly required in neonatal intensive care units around the world to secure the airway and provide respiratory support. It is indicated more frequently in preterm infants with an inverse relationship with the gestational age. The procedure itself has the potential to destabilise the infant with development of hypoxia and bradycardia. This could lead to a critical reduction in cerebral oxygenation which may have long-term effects on the neurodevelopment of these infants. In addition, the procedure can also be accompanied by hypertension, rise in intracranial pressure (ICP) and pulmonary vascular resistance (PVR). It is also not clear how well these alterations are documented in the clinical notes. This procedure is commonly preceded by face mask ventilation in an attempt to establish pulmonary functional residual capacity and improve the tolerance to the procedure. In recent years, inadvertent mask leak and airway obstruction have been identified as major impediments to the efficacy of mask ventilation in both human and manikin studies. These are difficult, if not impossible to identify clinically. Studies also show that with appropriate training, skills in face mask ventilation do improve with reduction in mask leak. The mask ventilation skills are also critically important for neonatal stabilisation and resuscitation at the time of birth. With the recent literature supporting non-invasive respiratory support over routine intubation and ventilation, proficiency in mask ventilation is essential for the paediatric doctors and nurses. Objectives: The objectives of this work included a. To quantify the hypoxia burden associated with the procedure of endotracheal intubation in extremely preterm infants b. Assessment of clinical documentation of the procedure of endotracheal intubation including the deterioration in vital signs experienced by the infant c. To study face mask leak with different peak inspiratory pressures (PIP) in a neonatal manikin model ventilated by a T-piece resuscitator (TPR) d. To study the effect of different inflation rates and different flow rates with a TPR on the delivered pressures and mask leak in a neonatal manikin model with normal lung compliance Methods: a. Study of endotracheal intubation in preterm infants: This was a retrospective study of the intubations performed in extremely preterm infants ( 0.05) in the mask leak with the three PIP settings. No statistically significant differences were seen in RR and Ti with the three PIP settings. There was a significant rise in PEEP as the PIP increased with a mean PEEP of 7 cm H2O (95% CI 6.7-7.3) at a PIP of 40 cm H2O. Failure to achieve the desired PIP was observed especially at the higher settings. c. In the study of the effect of different inflation and gas flow rates with a TPR, 20 staff members participated and a total of 8185 inflations were analysed. At all the flow rates, the PEEP increased significantly as the inflation rate increased. The magnitude of this increase was more pronounced the lower the flow rate was. At a given inflation rate, the PEEP was highest at a flow rate of 5 LPM and lowest at a flow rate of 15 LPM. The PIP was statistically significantly higher with RR of 60/min at a flow of 5 LPM and with RR of 30/min at flow of 10 and 15 LPM but these differences are clinically not significant. The mask leak was overall very low with the lowest leak observed at a flow rate of 10 LPM. No clear pattern could be discerned regarding the leak either in relation to the flow rate or inflation rate. The VTe decreased as the inflation rate increased across all the flow rates and this was in keeping with the decreasing Ti. Conclusions: Neonatal endotracheal intubation is commonly accompanied by significant hypoxia, bradycardia and BP fluctuations. Increasing number of attempts lead to a greater hypoxia burden. The procedure of intubation is inadequately documented in the clinical notes. Through the mask ventilation studies, the phenomenon of inadvertent PEEP with high inflation rates and low gas flow rates in a compliant lung model was identified. The mask leak does not vary as a function of inflation pressure or gas flow rate if other parameters are kept constant