Ignored concepts in ICU : Protecting RV from ventilator stress

We know the right ventricle is a weak pump compared to LV. This is evident from the triangular pressure-volume loop of RV. RV not only generates less pressure, its thin wall and its direct connectivity to the extrathoracic compartment make it vulnerable to hemodynamic fluctuations whenever Intrathoracic pressure swings. Note the lowly lying pressure-volume loop of the right ventricle. RV is a too gentle chamber and needs to be handled with extreme care especially when it is failing acutely. Patients on ventilators are typically exposed to iatrogenic rise and fall in right heart pressure. If continuous airway pressure is kept high it’s directly add on to RV afterload. The second adverse event is through interrupting venous return (preload).   Effect of mechanical ventilation on RV RV preload is reduced (If they drop too low – they are equivalent to be in “Status Valsalva maneuver” )  RV afterload increases when Inspiratory airway pressure is increased. ( If RV is grossly dilated it may encroach LV and interfere with its function (Reversed Bernheim effect ) Many of the unexplained hypotension and reduced cardiac index are due to suboptimal ventilator setting Ventilator increases the mean RA pressure, and if there is PFO, it can shunt right to left and aggravate the preexisting systemic hypoxia.  In some of the situations where RV is already in the fighting mode for survival, imagine its plight when it had to take on the adverse...
Source: Dr.S.Venkatesan MD - Category: Cardiology Authors: Tags: Uncategorized impact of mechanical ventilator on rv right ventricle peep settings for rv failure post heart transplant ventilatory settings rv dysfunction in pulmonary rv function dysfunction rv infarction rv pressure volume loop Source Type: blogs