I am Unable to understand why peak inspiratory pressure rises in endobronchial intubation

NEET PG
#1

i am Unable to understand why peak inspiratory pressure rises in endobronchial intubation.

Suppose you were providing normal volume of air(say Vml) which got distributed like V/3 in airway + V/3 in each lungs. Now you are ventilating only one lung so now inspite of V/3, 2V/3 is going inside one lung. So tidal volume is kept low to prevent barotrauma but

  1. more volume of air if goes in then more will have to come out which will require more time so it can lead to air trapping inside creating AutoPEEP(Physiological increase in PEEP)

  2. Chances of Kinking of tube is more in bronchi so will again prevent air to escape within time and will again increase chance of increasing air trapping inside( again will create AutoPEEP)

  3. more volume going inside will inflate alveoli extensively: more alveoli radius more will be the surface tension and more collapsing tendency will be there. So to break it PEEP is slightly kept on higher side

  4. as one lung is not even getting ventilated so Total FRC decreases and there’s no more optimum FRC to achieve effective ventilation. So to increase FRC to optimum level PEEP is slightly increased on higher side to have effective ventilation.