A patient is receiving mechanical ventilation with a fractional inspired oxygen (F_IO₂)of 0.85 and a positive-end-expiratory pressure (PEEP)of 5 cm H₂O.His arterial partial pressure of oxygen (P_aO₂)is 68 mm Hg,arterial oxygen saturation (S_aO₂)is 88%,and partial pressure of end-tidal carbon dioxide (PetCO₂)is 32 mm Hg.Over the next few minutes his PEEP is titrated resulting in the following data: At 0740 the single breath carbon dioxide curve (SBCO₂)curve shifted to the right.What action should the respiratory therapist take at this time?

Question

Quizplus · Accepted Answer

The increase in positive-end-expiratory pressure (PEEP)to 15 cm water (H₂O)seems to have decreased pulmonary perfusion because of overinflation of the alveoli.This is evident by the decrease in the partial pressure of end-tidal carbon dioxide (PetCO₂)to 25 mm Hg and the right shift in the single breath carbon dioxide curve (SBCO₂).Increasing the fractional inspired oxygen (F_IO₂)will not address this problem.Reducing the set tidal volume will increase the PetCO₂ but will not improve the pulmonary circulation.Continuing to increase the PEEP will further reduce pulmonary perfusion and cause more dead space.Reducing the PEEP back to 12 cm H₂O will optimize the PEEP and reduce overinflation.

A Patient Is Receiving Mechanical Ventilation with a Fractional Inspired