Improving the Paediatrician's Understanding of Mechanical Ventilation: The Importance of Context

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Dear Editor,

The United Nations Educational, Scientific and Cultural Organization Institute for Lifelong Learning contends that ‘arguably the most important quality dimension in adult education is the relevance of provision to learners’.[1] The translational value of the educational material on mechanical ventilation (MV) for paediatricians, provided by Muhlethaler and Malcolm,[2] in improving quality of care and reducing harm could be further enhanced if it was linked to the functional context in which paediatricians manage these babies. This context comprises short-term (hours) ventilation of babies in non-tertiary special care nurseries (SCNs) utilising complex technology with which medical and nursing staff have limited exposure. They require clear and simple guidance that matches the resources available. In this regard, I make the following suggestions for paediatricians faced with a baby requiring MV:

  1. Consultation: Discuss the baby with a neonatologist from the regional retrieval service at the earliest opportunity.
  2. Monitoring oxygenation: Apply a pulse oximeter to the right hand wherever feasible. Acceptable, pragmatic, short-term saturation target is 90–95% in both the preterm baby and term baby.[3] Providing normal values for paO2 is of limited value, as single arterial stab sampling is beyond the skill set of most recently trained general paediatricians. Indwelling arterial lines are rarely indicated and potentially harmful outside the neonatal intensive care unit (NICU) setting.
  3. Ventilator settings: Anecdotally, it is impressive how often initial ventilator settings of peak inspired pressure of 20, positive end expiratory pressure of 5, rate of 40–60 and inspiratory time of 0.3 s, coupled with a fraction of inspired oxygen (FiO2) matched to target saturations, leads to an acceptable pCO2 (40–55 mmHg). In consultation with a neonatologist, these settings can be readily modified based on the presence or absence of lung disease, oxygen requirements, a capillary pCO2 and the clinical features.

Discussion about tidal volumes, minute ventilation, volutrauma and calculation of mean airway pressure, while clearly relevant in the NICU, are of limited use in other contexts. Most non-tertiary SCNs do not have the resources to measure expired tidal volume so advice on how to optimise ventilation through direct manipulation of tidal volume is irrelevant.

The clinical priorities for paediatricians in relation to MV include correct and secure placement of an appropriate size endotracheal tube, maintenance of its patency and position, correct setup of the ventilator including a functional humidifier, and ensuring neither oxygen nor carbon dioxide are too high or too low as both are associated with harm. The material provided by Muhlethaler and Malcolm is important for overall understanding of MV but needs to be contextualised to the setting where it is being used to best realise the objective of improving effectiveness and safety of care.

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