6 minutes per day has 100% sensitivity and specificity for mortality prediction among VAP patients.DiscussionIn Crenolanib GIST the current study we found that GER occurred in up to 91.6% of all mechanically ventilated critically ill patients of either VAP or non-VAP patients. Many previous studies reported that the incidence of GER is increased in critically ill mechanically ventilated patients with the acidic reflux reaching up to 80% and bile reflux (duodenogastroesophageal reflux (DGER)) reaching up to 60% [3,10]. Another study found that the GER reached up to 74% in patients with nasogastric tube (NGT) which increased to 81% in supine position [11].

The patients are defined to have abnormal esophageal bile reflux (DGER) if the fraction of the time that the esophageal mucosa is exposed to alkaline refluxate exceeds 4% of the total study time and pathological acidic reflux if the fraction of the time that the esophageal mucosa is exposed to a refluxate with pH less than 4 exceeds 4% of the total recording time [12]. Previous studies demonstrated that sedatives [3] and adrenergic drugs [13] do increase reflux. In the current study, a great proportion of the studied patients were on those suspected medications; however, the frequency of use was not different between VAP and non-VAP groups.In the present study, there was a significant increase in GER parameters including total acidic time, number of reflux episodes, number of long reflux episodes longer than five minute, longest reflux time, reflux index and total reflux time in VAP than non-VAP patients.

Alkaline reflux was more common than acidic one, and there was no statistically significant difference in alkaline pH parameters between VAP and non-VAP patients. The use of acid suppressive medications were reported to increase frequency of non acid reflux [14]; however, in the present study, patients using these medications were excluded. The demonstrated alkaline reflux can be explained by duodenogastric reflux. Duodenogastric reflux is the retrograde flow of duodenal contents into the stomach that then mix with acid and pepsin. These agents can reflux into the esophagus (ie, DGER) and cause gastro-esophageal reflux disease [15].The mortality rate in our study among VAP patients was 75%, but in non-VAP patients was 25%. The difference was statistically significant.

In general this high mortality rate can be attributed to the highly pathogenic organisms that have been isolated in cultures as well as the pulmonary devitalizing effect of severe acid reflux. This was in agreement with other work [16,17] that reported high mortality rate of VAP patients.In the current study, all acidic parameters of pH metric results were significantly higher among non-survivors indicating a strong relation between acidic reflux Batimastat and high mortality rate in VAP patients. Acid and pepsin are the major factors responsible for symptoms and esophageal mucosal damage in gastro-esophageal reflux disease.