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Evaluation of Gastric pH and Guaiac Measurements in Neonates Receiving Acid Suppression Therapy During Extracorporeal Membrane Oxygenation
Author(s) -
Crill Catherine M.,
Bugnitz Mark C.,
Hak Emily B.
Publication year - 2004
Publication title -
pharmacotherapy: the journal of human pharmacology and drug therapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.227
H-Index - 109
eISSN - 1875-9114
pISSN - 0277-0008
DOI - 10.1592/phco.24.13.1130.38085
Subject(s) - ranitidine , medicine , extracorporeal membrane oxygenation , antacid , gastroenterology , anesthesia , gastric acid , stomach
Study Objectives. To assess gastric pH measurements, evaluate the frequency of guaiac‐positive gastric aspirates, and characterize the appearance of gastric aspirates in neonates receiving acid suppression therapy during extracorporeal membrane oxygenation (ECMO). Design. Retrospective, observational study. Setting. Intensive care unit in a 225‐bed tertiary care pediatric referral hospital. Subjects. Thirteen neonates receiving ECMO. Measurements and Main Results. Gastric pH measurements, guaiac test results, appearance of gastric aspirates, and ranitidine and antacid dosing were recorded. On ECMO day 1, mean ± SD gastric pH was 4.3 ± 2.8 in the five neonates whose pH was documented. Intravenous ranitidine 2.9 ± 0.4 mg/kg/day was started in all neonates by ECMO day 2. Gastric pH was less than 4.0 in seven neonates; these low pH values accounted for only 10% of gastric pH measurements. The frequency of positive guaiac results in neonates with pH measurements below 4.0 was 27% compared with 41% for neonates with a gastric pH of 4.0 or greater (p=0.125). Guaiac tests were positive in 69 (42%) aspirates in 11 neonates. Of the guaiac‐positive aspirates that had a corresponding pH measurement, 94% had a pH of 4.0 or greater. Guaiac‐positive aspirates had evidence of bile (49%), antacid (17%), and blood (7%) in gastric fluid. In six patients, ranitidine dosages were increased to 3.9 ± 0.6 mg/kg/day due to low pH and/or positive guaiac results. In two of these neonates, gastric pH remained below 4.0 in nine of 35 pH measurements despite increased ranitidine dosing. Guaiac results remained positive in all subsequent aspirates in five out of six of these neonates. No neonates developed clinically significant upper gastrointestinal bleeding (UGIB). Conclusions. Gastric pH is variable in neonates receiving histamine 2 ‐receptor antagonist and antacid therapy during ECMO, and gastric pH of 4.0 or greater does not decrease the frequency of guaiac‐positive aspirates. Higher gastric pH measurements are confounded by duodenogastric reflux and the presence of blood and/or antacid in gastric fluid. Motility agents in combination with acid suppression therapy for prevention of UGIB may be necessary in this setting based on gastric pH measurements, appearance of gastric aspirates, and guaiac testing.