GASTRIC-EMPTYING IS IMPAIRED IN PATIENTS WITH SPINAL-CORD INJURY

Objectives: The rate and completeness of gastric emptying (GE) are maj or determinants of the bioavailability of oral medication, and the eff iciency of gastric emptying is highly dependent on an intact central n ervous system. Hence, in spinal cord injury (SCI), an impairment in ga stric emptying could significantly diminish drug efficacy, Methods: We evaluated posture-dependent (seated and supine) gastric emptying of a n isotopically-labeled liquid meal in six quadriplegic subjects. The t ime-course profile of the gastric elimination of a radionuclide was fo llowed for up to 120 min using serial anterior scintigraphy, and the d isappearance of radioactivity from the stomach was described by both a mono- and biexponential fit of raw data. A half-time of gastric empty ing (GE(t1/2)) was estimated from each curve and compared to GE(t1/2) derived from able-bodied (intact neuraxis) experimental and historic c ontrol populations. Results: The mean GE(t1/2) in quadriplegic subject s (monoexponential curve fit) was significantly increased to 43.4 +/- 26.0 min in seated SCI subjects (95% CI 13.5-73.2, p < 0.05) and to 50 .5 +/- 48.0 min in supine SCI subjects compared to supine experimental and historic control values of 10.1 +/- 8.8 min (95% CI 2.3-18.0, p < 0.05) or 12.0 +/- 3.0 min (95% CI 9.4-14.8, p < 0.05), respectively, A small, nonsignificant trend towards an increased rate of GE (decreas ed GE(t1/2)) was observed in seated SCI subjects. Conclusions: We conc lude that gastric emptying is impaired in subjects with cervical SCI. Comparative studies of gastric emptying in subjects with SCI should in corporate concurrently studied, control subjects and employ experiment al methods that are not constrained by truncated data collection perio ds, The convention of forcing GE data to conform to a monoexponential pattern of evacuation ignores time-dependent multiphasic patterns of G E and does not support serendipity.