Introduction
Severe traumatic brain injury is often accompanied with different degrees of respiratory disorders, thus resulting in hypoxic asphyxia, elevated intracranial pressure, and these conditions further deteriorate the disease. Tracheotomy, which established an artificial airway, could maintain respiratory tract patency and is a key operation for the early treatment of severe traumatic brain injury1. During normal breathe, the upper respiratory tract will warm and wet the inhaled gas. But when an artificial airway is established, the warming and humidification effects of the patients’ respiratory tract is destroyed, the dry gas can further damage the trachea and bronchial mucosa2, and the movement of respiratory cilia was affected, which causing respiratory tract blockage, pulmonary dilatation, pneumonia, posterior pituitary dysfunction and the following cognitive dysfunction3-5. Therefore, the gas must be humidified before inhaled in, that is, airway humidification, and previous study had proved that heated humidification improves clinical outcomes in children with tracheostomies 6. And study recommended humidification in both invasive and noninvasive mechanical ventilation7, which suggested that humidification is essential for airway protection.
At present, there are many methods for airway humidification applied in clinical. Each method has its own disadvantage8-10, so comparative studies had been carried out, for instance, studies had compared the advantages of Heat and moisture exchanger (HME) and heated humidifiers (HHs) in adults and children need mechanically ventilation, though no difference was found in their study, the authors suggested further comparing of HMEs to HHs in paediatric and neonatal patients11. To date, the studies but was not sufficient, especially for some specific disease. Therefore, it is urgent to carry out systematic evaluation of some other humidification methods that frequently used in clinical, and to find out the most suitable method for airway humidification in patients with severe traumatic brain injury. In view of the fact that the common airway humidification method has been used in patients with severe traumatic brain injury in neurosurgery, and its advantages and disadvantages had also been experienced in our hospital, we chose three most respected methods in the world for comparison. We aim to select the most suitable method of airway humidification for patients with severe brain injury.