Safety Study of Inhaling Carbon Monoxide in Healthy Volunteers

Post operative ileus (POI), a temporary paralysis of the intestines, is a serious health care problem. It normally occurs in all patients after surgery to the abdomen but in some cases can result in serious complications. The objective of this study is to determine if inhaling very low doses of carbon monoxide (CO) before and after colon surgery will shorten the duration of normal POI and/or prevent the development of POI complications in patients undergoing colon surgery.

This preliminary study will be conducted in ten healthy volunteers to monitor for blood levels and adverse effects that occur at different durations of exposure of inhaled CO to establish a safe dose for patients in the main trial. For the main trial, patients requiring surgery to their colon will be assigned randomly to receive one hour treatments of either CO or oxygen by face mask before and after their operation.

We hypothesize that healthy volunteers will be able to tolerate 1 hour doses of 250 ppm of CO with minimal side effects. It is also anticipated that for each dose of CO administered, the blood levels of CO will remain well under poisonous levels. Finally, we anticipate blood levels of CO will return to baseline level within 24 hours following the last dose of CO.