Biomedical subjects
Werner K H Kauer
Publications and source records attributed to Werner K H Kauer.
Bile reflux in the constellation of gastroesophageal reflux disease.
Gastric acid and bile acids are a particularly noxious combination when they interact with the mucosa of the upper intestinal tract. There is a critical pH range, between 3 and 6, in which bile acids exist in their soluble, un-ionized form, can penetrate cell membranes, and accumulate within mucosal cells. At a lower pH, bile acids are precipitated, and at a higher pH, bile acids exist in their noninjurious ionized form. Experimental, clinical, and immunohistochemical studies show that acid and bile reflux are increased in patients who suffer from GERD, are the key factor in the pathogenesis of Barrett's esophagus, and possibly are related to the development of esophageal adenocarcinoma.
Role of acid and bile in the genesis of Barrett's esophagus.
Clinical and experimental studies have shown that acid and bile reflux are increased in patients who have Barrett's esophagus. The combination of both seems the key factor in the pathogenesis of Barrett's esophagus. This factor has been confirmed by immunohistochemical studies that show that environmental factors, such as acid and bile, are involved in the pathogenesis of Barrett's esophagus. There is a critical pH range between 3 and 6 in which bile acids exist in their soluble, un-ionized form; can penetrate cell membranes; and accumulate within mucosal cells. At a lower pH, bile acids are precipitated, and at a higher pH, bile acids exist in their noninjurious ionized form. Thus incomplete gastric acid suppression, as is the case with most medical treatment regimens for gastroesophageal reflux, may in fact predispose to the development of Barrett's esophagus.
Intratracheal long-term pH monitoring: a new method to evaluate episodes of silent acid aspiration in patients after esophagectomy and gastric pull up.
Aspiration of gastric contents is considered a leading cause of postoperative pulmonary complications after esophagectomy and gastric pull up but has been difficult to diagnose. We used intratracheal long-term pH monitoring to evaluate the prevalence of aspiration of gastric contents in patients undergoing these operations. Continuous intratracheal pH monitoring was carried out during the first 72 postoperative hours in 16 patients with esophageal carcinoma who had undergone esophagectomy and gastric pull up. A drop in the pH to less than 4 was defined as an episode of acid aspiration. All patients except one tolerated the probe without any difficulties. Episodes of acid aspiration could be detected in 12 (80%) of 15 patients (5 of 8 after transhiatal esophagectomy, 7 of 7 after transthoracic esophagectomy, 2 of 5 with reconstruction in the anterior mediastinum, and 9 of 10 with reconstruction in the posterior mediastinum). The number of aspiration episodes was significantly higher during postoperative day 1 (P=0.03) compared to postoperative days 2 and 3. Two patients developed pneumonia later in the postoperative course. Both of them had several episodes of acid aspiration detected by pH monitoring immediately postoperatively. Intratracheal pH monitoring is a safe, feasible, and well-tolerated method for detecting episodes of acid aspiration after esophagectomy and gastric pull up. Aspiration of gastric contents is a common phenomenon particularly during the first 24 postoperative hours after transthoracic esophagectomy and gastric pull up in the posterior mediastinum and appears to correlate with the development of postoperative pneumonia.