ABSTRACT
Heightened perception of gastrointestinal sensation is termed visceral hypersensitivity (VH) and is commonly observed in patients with gastrointestinal disorders. VH is thought to be a major contributory factor in oesophageal disease, particularly gastro-oesophageal reflux disease that does not respond to standard (proton pump inhibitor) treatment, and in functional heartburn. Clinical tools that can help phenotype according to the mechanism of chronic pain and thus allow targeted drug treatment (e.g. with pain modulator therapy) would be very desirable. A technique that produces repeatable and controllable thermal stimuli within the oesophagus could meet this need. The aims of this study were to develop a method for linear control of the heat stimulation in the oesophagus, to assess the reproducibility of this method, and obtain normal thermal sensitivity values in the distal and proximal oesophagus. The 7 mm diameter Peltier-based thermal device was investigated on 27 healthy subjects using a heating ramp of 0.2 °C s(-1). The pain detection threshold (PDT) temperature was recorded. To assess the reproducibility of the device, each subject underwent the procedure twice, with a minimum of two weeks between each procedure. The mean PDT temperature measured in the distal oesophagus, was 53.8 ± 2.9 °C and 53.6 ± 2.6 °C, for visits 1 and 2 respectively. The mean PDT temperature measured in the proximal oesophagus was 54.1 ± 2.4 °C and 54.0 ± 2.8 °C, for visits 1 and 2 respectively. The reproducibility of the PDT temperature in the distal and proximal oesophagus, was good (intra-class correlation >0.6). Future studies should be aimed to determine whether oesophageal thermal sensitivity can act as a biomarker of transient receptor potential vallanoid 1 upregulation.
