The intention is to enroll a specific sample of intubated patients. To compare the effect of respiratory gas conditioning on lung deposition and considering the well-known influences of lung pathology on lung deposition, intubated patients with healthy lungs will be included. Postoperative neurosurgery ventilated patients respond perfectly to this criteria. A previous study including 17 postoperative neurosurgery patients was performed in 2013 with a perfect collaboration between the ICU and the Department of Neurosurgery and Anesthesiology.

Inclusion Criteria:

• Aged 18 years or older
• Postoperative neurosurgery intubated patients admitted for brain neurosurgery in the ICU (Intensive care neuro-traumatologic and Toxicologic)- With a healthy lung function.
• Signed and dated informed consent should be obtained in accordance of local regulations.

Exclusion Criteria:

• Spine neurosurgery
• History of cardiovascular and pulmonary disease
• Extubation immediately after surgery
• Modification of the allocated humidification technique before or during the nebulization (heated-humidifier deficiency or safety concern)
• Inaccurate quantification of aerosol deposition (i.e., artifacts or overlap of tracheal and pulmonary deposition).