Glass and antimony electrodes for oesophageal pH monitoring in distressed infants: how different are they?
OBJECTIVE
Although antimony electrodes are by far the most popular for performing oesophageal pH monitoring, there are few data comparing the accuracy of glass and antimony electrodes. Therefore, we tested the accuracy of both electrodes in the prediction of oesophagitis.


METHODS
pH monitoring using a glass electrode and an antimony electrode was performed in 60 distressed infants, aged between 1 and 6 months. An upper endoscopy with oesophageal biopsies was also performed in all infants.


RESULTS
A reflux index (percentage of the total time with pH < 4.0) greater than 5% was considered to be abnormal and was found in 40/60 patients. Histological oesophagitis was present in 26/60 infants. The reflux index was > 5% with the glass electrode in 18/26 children with histological oesophagitis and with the antimony electrode in 10/26 children with histological oesophagitis. Histology of the oesophagus was normal in 22/40 children with abnormal pH monitoring. With the glass electrode, the mean reflux index in the group with oesophagitis was significantly higher than in the group with normal histology, although there was an important overlap. With the antimony electrode, the mean reflux indices in the groups with and without oesophagitis were not different. Regarding normal/abnormal, there was discordance in 35% of the pH studies. No reflux index could be related to a clinically useful sensitivity and specificity to predict oesophagitis.


CONCLUSIONS
The reflux index does not accurately predict oesophagitis. Oesophageal pH monitoring and endoscopy provide complementary information.
Vandenplas
Yvan
Y
Department of Paediatrics, Academic Children's Hospital, Free University of Brussels, Brussels, Belgium. yvan.vandenplas@az.vub.ac.be
Badriul
Hegar
H
Verghote
Marc
M
Hauser
Bruno
B
Kaufman
Leonard
L
D000965:Antimony; D016001:Confidence Intervals; D004566:Electrodes; D004941:Esophagitis / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D004947:Esophagus / Q000473:pathology; D005764:Gastroesophageal Reflux / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D005898:Glass; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007223:Infant; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity
D000965:Antimony