SUMMARY Using breath hydrogen analysis after 139 mmol (50 g) oral lactose load, we investigated the prevalence of lactose malabsorption in 200 Greek adults and examined the relationship between symptoms and small bowel transit time. One hundred and fifty subjects had increased breath hydrogen concentrations (>20 ppm) after the lactose load. In these individuals peak breath hydrogen concentration was inversely related to small bowel transit time (r= -0*63, t=6.854, p<0001) and the severity of symptoms decreased with increasing small bowel transit time. Lactose malabsorbers with diarrhoea during the lactose tolerance test had a small bowel transit time of 51±22 minutes (x±SD; n=90) which was significantly shorter than the small bowel transit time of patients with colicky pain, flatulence, and abdominal distension (74±30, n=53; p60%
SUMMARY Concentration of oxygen, methane, and hydrogen were measured in intracolonic gas samples aspirated through the colonoscope at the time of colonoscopy from 46 patients. Of the above patients 20 prepared either with mannitol (n=10) or with castor oil (n=10) had the instrument passed to the caecum without air insufflation or suction. After mannitol, mean intracolonic hydrogen concentration (4.07%) was significantly higher (p<0.001) than after castor oil (0.51%). Mean oxygen and methane concentrations were approximately similar. Potentially explosive concentrations of hydrogen (>4.1%) and or methane (>5%) were present in 6/10 patients given mannitol and 2/10 patients given castor oil. Nevertheless only one patient from each group had coexisting oxygen concentrations of more than 5% producing thus a combustile mixture. Routine colonoscopy (using air insufflation and suction) was performed in 26 patients prepared with mannitol. Mean intracolonic hydrogen and methane was 0-63% and 0-88% respectively. The highest recorded concentration of hydrogen was 2.6%, and of methane 2.1%, while all patients had oxygen concentrations of more than 5%. It is suggested, therefore, that routine insufflation and suction before colonoscopic electrosurgical polypectomy should result in safe levels of these gases. The remote possibility of pockets of undiluted gas in explosive concentration, however, indicates the use of an inert gas such as carbon dioxide if mannitol preparation is used before electrosurgery.
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