On December 6, 1997, at 0930 central standard time, a Piper PA-24, N8452P, was substantially damaged when it impacted the ground near Cairo, Missouri. The 14 CFR Part 91 flight originated from Great Bend, Kansas, at 0710, en route to Topeka Forbes Airport, Topeka, Kansas. The pilot fell asleep and the airplane ran out of fuel. The pilot had a toxic level of carbon monoxide in his blood. The pilot received minor injuries. Visual meteorological conditions prevailed and no flight plan had been filed. The pilot reported that he had climbed to 5,500 feet mean sea level and trimmed the airplane at cruise power settings. He set up the GPS navigation system for a direct flight to the Topeka Forbes Airport, and then engaged the autopilot. He reported that he switched the fuel selector to the auxiliary fuel tank. He reported that he remembered passing Herrington, Kansas, at which time he set up his radios for arrival at the Topeka Forbes Airport. He reported that he could not remember anything else about the flight until he awoke in a hay field in Cairo, Missouri. He reported that when he awoke he was confused. He thought he was still airborne and making an approach to the airport. When he finally became oriented he realized he was on the ground. He walked to a farmhouse where he received assistance. The pilot was taken to a hospital. It was determined that the pilot had succumbed to carbon monoxide poisoning. His blood level indicated a toxic level of 26.8%. The wreckage path indicated that the airplane had touched down in a flat hay field. The airplane skidded on its belly for about 525 feet before hitting a wire fence and small trees. There was no indications that the airplane's wings hit the ground during the 525 foot skid. The airplane was inspected. The right muffler had a crack around one of its seams, which would allow exhaust fumes into the cabin heater housing and into the airplane's cabin. The airplane had recently been taken to an airplane service center for an annual inspection. The pilot decided to fly the airplane before the annual inspection had been completely signed off.