Abstract

The influence of thoracic epidural anesthesia, spinal anesthesia, and a painful stimulus on gastric emptying, orocecal transit time, and small intestinal transit were studied in nine healthy volunteers. Gastric emptying was measured by the acetaminophen absorption method. Orocecal transit time was determined by measuring end-expiratory hydrogen concentration. Small intestinal transit was calculated from measurements of the orocecal transit time and gastric emptying. Cold pain stress with intermittent immersion of the feet in ice-cold water was used as a painful stimulus. Each volunteer was investigated on four occasions: 1. during nociceptive stimulation of the feet (cold pain); 2. during low spinal anesthesia with block of the afferent nerves from the nociceptive stimulated area; 3. during thoracic epidural anesthesia (0.5% bupivacaine) with block of the efferent nerves to the stomach and small intestine but with intact afferents from the nociceptive stimulated area; 4. as a control study without pain and anesthesia. Without spinal anesthesia, immersion of the feet in cold water was very pianful and caused a circulatory stress reaction with increased blood pressure. Cold pain stress in itself did not influence gastric emptying, orocecal transit time, or small intestinal transit. Neither did epidural or spinal anesthesia during cold pain stress influence these variables of gastroin-testinal motility. Thus, low spinal anesthesia or thoracic epidural anesthesia in itself did not influence gastric emptying, orocecal transit, or small intestinal transit.