The fractal nature of human gastro‐oesophageal reflux

• Published in: Alimentary pharmacology & therapeutics Vol. 22; no. 9; pp. 823 - 830
• Main Authors: GARDNER, J. D., YOUNG, W., SLOAN, S., ROBINSON, M., MINER, P. B.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.11.2005; Blackwell
• Subjects: Adolescent; Adult; Aged; Biological and medical sciences; Digestive system; Esophagus; Esophagus - physiopathology; Female; Fractals; Gastric Acidity Determination; Gastroenterology. Liver. Pancreas. Abdomen; Gastroesophageal Reflux - physiopathology; Humans; Hydrogen-Ion Concentration; Male; Medical sciences; Middle Aged; Other diseases. Semiology; Pharmacology. Drug treatments; Stomach - physiopathology; Time Factors; Human; Gastroesophageal reflux; Digestive diseases; Esophageal disease
• ISSN: 0269-2813; 1365-2036
• DOI: 10.1111/j.1365-2036.2005.02665.x

Summary Background : We are unaware of the analyses of time series data resulting from 24 h recordings of human gastric or oesophageal pH. As a result, we have no understanding of the quantitative changes in gastric or oesophageal acidity over time, the patterns that might characterize these changes, or the physiological significance of gastro‐oesophageal reflux. Aim : To examine the time series for gastric and oesophageal pH. Methods : Detrended fluctuation analysis and lag analysis were used to analyse data from 24 h recordings of oesophageal and gastric pH in five normal subjects and five subjects with gastro‐oesophageal reflux disease. Results : Analyses of the patterns of gastric and oesophageal pH over time in normal subjects and subjects with gastro–oesophageal reflux disease indicate that the fluctuations in pH are self‐similar across different time scales and are consistent with an underlying fractal process. Furthermore, there is a significant statistical association between sequential pH values separated by as much as 2.2 h. Conclusions : We hypothesize that the self‐similar, fractal pattern encodes information about gastric acidity and that the oesophagus decodes this information and, when appropriate, may signal the stomach to reduce gastric acidity. Subjects with gastro‐oesophageal reflux disease might have an impaired oesophageal–gastric feedback mechanism that results in increased gastric acid, which reflux from the stomach into the oesophagus.