Distal oesophageal ph monitoring for gastro-oesophageal reflux.

We investigated eight hour distal intra-oesophageal ph testing to see if this could replace the traditional 24 hour test period without significant loss of sensitivity in the diagnosis of gastro-oesophageal reflux (GOR) disease in symptomatic refluxers. Thirty-four patients were tested, all of whom had classical De Meester symptoms of GOR. All patients were admitted to hospital and commenced on 24 hour ambulant ph monitoring of the distal oesophagus. This was followed by a period of eight hour testing. The following variables were determined: (i) total reflux time, (ii) number of reflux episodes (total, upright and supine), (iii) longest episode of reflux, (iv) percent of time that ph was below four (total, upright and supine). All patients underwent endoscopic examination of the oesophagus subsequently. Twenty four hour monitoring resulted in a positive diagnosis of GOR in 26 of 34 patients, giving an overall sensitivity of 75%. Eight hour testing was positive in 23 patients (sensitivity of 68%, not significantly different). The best correlations were obtained when comparing total reflux episodes (r = 0.75, p less than 0.001), and the percent time ph less than 4 (total) (r = 0.69, p less than 0.001). Nineteen patients had evidence of oesophagitis on endoscopy, and in all such patients both eight and 24 hour testing were positive. We conclude therefore, that eight hour ph monitoring can be reliably used in the diagnosis of pathological GOR in patients symptomatic for acid reflux.