Microprocessor controlled movement of liquid gastric content using sequential neural electrical stimulation

Abstract

Background - Gastric electrical stimulation has been attempted for several years with little success. Aims - to determine whether movement of liquid gastric content could be achieved using microprocessor controlled sequential electrical stimulation. Methods - Eight anaesthetised dogs underwent laparotomy and implantation of four sets of bipolar stainless steel wire electrodes. Each set consisted of two to six electrodes (10x0.25 mm, 3 cm apart) implanted circumferentially. The stomach was filled with water and the process of gastric emptying was monitored. Artificial contractions were produced using microprocessor controlled phase locked bipolar four second trains of 50 Hz, 14 V (peak to peak) rectangular voltage. In four of the dogs four force transducers were implanted close to each circumferential electrode set. In one gastroparetic patient the effect of direct electrical stimulation was determined at laparotomy. Results - Using the above stimulating parameters circumferential gastric contractions were produced which were artificially propagated distally by phase locking the stimulating voltage. Averaged stimulated gastric emptying times were significantly shorter than spontaneous emptying times (t(1/2) 6.7 (3.0) versus 25.3 (12.9) minutes, p<0.01). Gastric electrical stimulation of the gastroparetic patient at operation produced circumferential contractions. Conclusions - Microprocessor controlled electrical stimulation produced artificial peristalsis and notably accelerated the movement of liquid gastric content.