The use of a pressure-support ventilation regimen in the recovery of spontaneous respiration after heart operations

Pressure-support ventilation (PSV) with supporting pressure (SP) levels 20, 15, 13, 10, and 8 mm H2O was used in 111 patients with congenital heart disease after open-heart surgery during transfer to spontaneous respiration. PSV was associated with a significant decrease of respiratory rate and increase of respiratory volume (RV) at high SP levels. Respiration in the PSV mode permits the patient to control the inspiration flow, duration of inspiration phase, and RV, thus improving the patient-device synchronization. Cardiac index (CI) was changing with decrease of SP from 20-15 to 13 mm H2O in patients with different diseases during high SP PSV. This is caused by changed pulmonary circulation (transfer to intraacinar type) which increased the negative correlation between CI and chosen SP. In addition, CI depends not only on RV, but on the status of lung parenchyma as well.