Measurement by epigastric impedance of gastric emptying in diabetic autonomic neuropathy.

Changes in impedance across the epigastrium form the basis of a new non-invasive method of assessing gastric emptying of liquids. The apparatus is simple to use at the bedside and, in conjunction with conventional investigations, is of value in diagnosing gastroparesis in patients with diabetic autonomic neuropathy and symptoms of recurrent vomiting. We measured gastric emptying of liquids in 22 diabetics aged 33.4 +/- 9 years (mean +/- SD) with severe symptomatic autonomic neuropathy (mean heart rate variability 4.9 +/- 2.2 SD beats/min), and 15 normal controls. Median 'half emptying' time in the diabetics with autonomic neuropathy was prolonged overall but it was not always abnormal (12.25 min, range 6.5-greater than 30 compared to 8.0 min, range 3-17; p less than 0.01). Results in five diabetics with symptoms of recurrent vomiting corresponded with those using conventional radiological methods, confirming gastroparesis in three instances and excluding it in two. The effect of metoclopramide was also studied and was shown to accelerate gastric emptying in some but not all of the patients. Assessment of gastric emptying using the impedance method assists in establishing the diagnosis of gastroparesis and is of value for repeated measurements.