Gastrointestinal problems in children on home invasive mechanical ventilation
The gastrointestinal (GI) problems in critically ill patients who were given MV support in intensive care units have been demonstrated both in animal and human studies24-26. During MV, splanchic hypoperfusion seems to play an important role in the pathogenesis of GI complications due to cardiocirculatory dysfunction. In particular, it was reported that high positive end-expiratory pressure (PEEP) levels (PEEP >15 cmH2O) cause an increased right ventricular afterload which lead to an increase in right atrial pressure, decreased systemic venous return and cardiac output and splanchic perfusion respectively24-27. Also acute moderate increase in arterial carbondioxide level has been observed to increase hepatic and splanchic blood flow in a biphasic manner; initially reducing of blood flow due to sympathetic stimulation, then increasing blood flow due to direct vasodilator effect of carbondioxide28. Despite there are conflicting results on the effect of PEEP on hepatic blood flow as decreased or no change. The decrease in portal flow may be compansated with increased arterial blood flow in order to maintain hepatic blood flow29,30. The gastro-esophageal reflux disease, dysphagia, delayed gastric emptying and constipation are the most common gastrointestinal problems of the children with tracheostomy on MV31-33.