This study aimed to introduce the technique of tetra-probe, 24-hour pH monitoring for laryngopharyngeal reflux disease.

Tetra-probe, 24-hour pH monitoring was performed for 30 suspected cases of laryngopharyngeal reflux. The proximal probe was placed in the hypopharynx, just above the upper oesophageal sphincter, the second probe was placed in the middle oesophagus, the third probe was placed a few centimetres above the lower oesophageal sphincter, and the distal probe was placed in the stomach.

As the pH at the four sensor sites could be monitored simultaneously, gastric acid levels and gastroesophageal and laryngopharyngeal reflux could be examined. This pH monitoring technique enabled the pH relationship between the four sensor locations to be well documented, enabling gastric acid levels and patterns of reflux to be assessed. This procedure was also able to be used as a functional examination to evaluate anti-reflux medication efficacy.

Tetra-probe, 24-hour pH monitoring is a reliable functional examination for laryngopharyngeal reflux.

Double-probe, 24-hour pH monitoring remains the ‘gold standard’ for the diagnosis of laryngopharyngeal reflux disease, even though there is no consensus on how to interpret the data collected.

Tetra-probe, 24-hour pH monitoring was performed in 56 patients with suspected laryngopharyngeal reflux, in order to investigate patterns of laryngopharyngeal and gastroesophageal reflux.

The number of reflux episodes and the total and percentage time periods spent with pH < 4.0 were correlated with the distance of the probe from the lower oesophageal sphincter. The number of reflux episodes and the total and percentage time periods with pH < 4.0 were greater when patients were upright (i.e. during the daytime). There were few laryngopharyngeal reflux events recorded for pH levels of <4.0; however, there were a significant number of laryngopharyngeal reflux events recorded for pH levels of <5.0, a level capable of causing laryngopharyngeal reflux disease. When a pH level of <5.0 was used, the number, total time and percentage time of laryngopharyngeal reflux episodes was greater during the supine period (i.e. during sleeping) in a quarter of the cases, compared with results when a pH of <4.0 was used.

It is valid to use a pH level of 5.0 as indicative of laryngopharyngeal reflux in the hypopharynx.