Mechanically ventilated patients should be in a sitting or semi-sitting position during nebulization inhalation therapy. Domestic and foreign research and expert consensus recommend this position. When in a sitting or semi-sitting position, the patient's diaphragm moves downward and the chest cavity expands, which can increase the amount of bronchial gas exchange and improve the effect of nebulization therapy. For mechanically ventilated patients, the healthy side should be in a lying position and the head of the bed should be raised to 30~50° during nebulization therapy, which is conducive to the deposition of nebulized drugs. In addition, raising the head of the bed by 45° can reduce the incidence of ventilator-associated pneumonia (VAP) in mechanically ventilated patients.

Any obstruction in the ventilator circuit or tracheal tube, whether due to the accumulation of condensed water, tubing bends or kinks, may cause the aerosol to hit the narrow part of the tubing; the angle of the airway outlet will also affect the flow characteristics of the aerosol and increase the possibility of impact, resulting in aerosol waste and affecting the efficiency of atomization. It can be seen that before the ventilator atomization inhalation treatment, it is important to organize the ventilator pipeline and clean the condensed water.

The retention of airway secretions in patients will increase airway resistance, resulting in uneven distribution of aerosol in the airway and reduced drug deposition rate, thus affecting the effect of atomization treatment. Therefore, before atomization inhalation treatment, the sputum blocking the artificial airway should be fully aspirated.

In order to reduce the need to disconnect the ventilator circuit and avoid the escape of aerosols to contaminate the environment, it is recommended that mechanically ventilated patients use a closed suction device during aerosol inhalation therapy. The use of a closed suction device can reduce the risk of medical staff being exposed to contaminated condensed water and airway secretions. Compared with an open suction device, a closed suction device can prevent the occurrence of VAP, shorten the length of ICU stay, and reduce the rate of respiratory microbial colonization. Therefore, there is no need to remove the closed suction device during ventilator aerosol inhalation therapy.

Reference

[1] DHAND R.How should aerosols be delivered during invasive mechanical ventilation?［J］.Respir Care，2017，62（10）：1343-1367.

[2] WILLIAMS J P，ARI A，SHANMUGAM R，et al.The effect of different closed suction catheter designs and pmdiadapters on aerosol delivery in simulated adult mechanical ventilation with and without exhaled humidity ［J］.Respir Care，2018，63（9）：1154-1161.

[3] HESS D.The ventilator circuit ［ED/OL］. （2021 -10 -14）［2021-10-15］