Gastro-oesophageal acid reflux. Method for 12-hour continuous recording of oesophageal pH with analysis of records.

Description of method for continuous recording of oesophageal pH and automatic, electronic analysis of records. Stability of apparatus has been tested over 12 hours in the laboratory with different buffer solutions and gastric secretions with and without bile, and on 36 patients with oesophageal disorders. Drift of apparatus max. 0.2 pH units. The analyser, dividing the pH range into arbitrary intervals, performs a rapid and reliable analysis of single examinations from variable criteria. The temporal distribution of pH values into the intervals is expressed in percentages of the total time of recording. Reliability of the analyser was tested by analysis of a simulated pH curve on which changes in amplitude corresponded to the most rapid changes seen in practice. Deviation below one per cent. Repeated analyses of the same records showed a coefficient of variation for the various analytical interval to be 10-0.01 per cent. The method allows recording of the number of reflux episodes, duration of each episode and total duration of pH within chosen limits.