I noticed that if i put the patient in Trendelenburg position during proning in COVID-19 patients, the tidal volume significantly increased average 75 ml/breath. All patients were chemically paralyzed.
The only explanation I can think about is the regional difference of pleural and trans-pulmonary pressure by position change?
Any suggestion or theories?
Ehab Daoud
Hi Gaetsno
Thanks for the response
PCV, i never use VCV
you would think the gravitational forces would push the diaphragm encephalic towards tge lung thus worsening chest wall compliance and tidal volume?
Hi Ehab,
In fact, contrary to what Gaetano said, in the prone position the compliance of the chest wall, even the value of the thoracopulmonary compliance could be lower than in the supine position, since there is less movement of the ribs (sternum in position supine).
I think there might be better compliance associated with reopening the airways and alveolar areas. Another reason could be postural drainage of secretions. If you decrease Pvent = Compliance + Resistance with prone position, Volumen could increase in PCV
Dear Eduardo,
My answer was referred to trendelenburg in prone position, not in prone position "per se". I think the ribcage component of the cw would not be affected too much in trendellurg. What can change is the diaphragm position or the distribution of ventilation, that can justify the increase in compliance (and therefore of volume in PCV).
recruitment of the alveoli at the base of the lungs may be beneficial - the volume of the lung bases is larger than that of the apex, hence the increase in tidelvolume
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