Ventilating patients in the Cardiac Surgery Intensive Care Unit is typically straight forward. Moderate tidal volumes with an elevated Fi02, followed by a wean to pressure support ventilation once level of consciousness returns.
Typically this occurs within 4-6 hours upon the patients arrival into the CSICU.
However, there are situations where more aggressive ventilation strategies are required such as increased blood loss from mediastinal chest tubes (?peep), refractory hypoxemia from postoperative pulmonary dysfunction (PPD) (?peep and Fi02, PC ventilation, addition of NO, etc.), ?BP and circulation, etc.
There is a very good article in AMERICAN JOURNAL OF CRITICAL CARE, September 2004, Volume 13, No. 5 which helps explain its occurrence.
Please see tables 1 and 2 in this article for plausible explanations.
Read the full article here.