Gas Research and Laparoscopy

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Dr. Larry Demco

: "This is Dr. Larry Demco, and I’m at the Symposium on New Diagnostic Techniques in Laparoscopy in Miami, Florida. I’m here with Dr. Douglas Ott from Macon, Georgia. Dr. Ott has been instrumental in the area of gas research in laparoscopy. Can you tell us a little bit about the history of how we came to use carbon dioxide gas, and discuss its current problems?"

Dr. Douglas Ott: "Carbon dioxide gas is used because it’s inexpensive, easily available commercially, and comes in a convenient container. The problem with the gas is that it’s used at 70 degrees, it has less than 200 parts per million of water vapor, and it is unsterile. During surgery, a patient's abdomen is sterile, a warm 98 degrees, with a wet 95% relative humidity. So the combination of the unphysiologic raw gas in a circumstance of laparoscopy is not physiologic for the environment that we operate in, and it can have some detrimental outcomes and cause problems during these procedures."

Dr. Larry Demco: "You refer to certain problems – what is the main problem for a patient who is exposed to gas, let’s say, for a prolonged operation? What are the effects to the patient?"

Dr. Douglas Ott: "The main effect is that, because of the extreme dryness of the gas, the gas flow causes dessication of the peritoneal fluid covering the peritoneum, which in turn causes huge amounts of evaporation that reduces the patient’s temperature and causes hypothermia. As the water vapor is removed because of the difference between the normal circumstance and the dry gas, it then effects the surface of the peritoneal cells, which causes them to become damaged or to, in fact, die and be non-viable. It also changes the constitution of the peritoneal fluid, which in its normal state acts as a lubricant to prevent sticking of the peritoneal surface and reduce adhesions. By changing this peritoneal environment, there is an increased likelihood of peritoneal adhesions and the patient has hypothermia.

Another thing is that when you’re in the abdomen with the cold, dry gas there’s a large amount of fogging on the laparoscopic lens. When the warm, wet gas is used because the dew point is not reached, there’s reduced lens fogging by approximately 90%. Additionally, with the peritoneum being damaged during the procedure, there’s an increased production of prostaglandins and inflammatory chemicals that contribute to the patient’s post-operative pain. By using gas that’s been pre-conditioned by heating and hydrating, the patient has significant reduction in post-operative pain and significant reduction in the time it takes to return to normal function and work."

Dr. Larry Demco: "We were initially taught that the cause of the shoulder tip discomfort, which is very common with laparoscopy, is from the combination of the carbon dioxide and the water vapor, which produces carbonic acid and acts as an irritant. We thought this was the main contributing factor to shoulder tip pain. But if I hear you correctly, now we’re thinking it’s actually cell death as it releases the components of the cells which, in turn, causes the irritation of the diaphragm, peritoneal surface, and is then referred to the shoulder tip pain. Is that correct?"

Dr. Douglas Ott: "Yes, that’s correct. The production of carbonic acid is one that does occur, and it reaches equilibrium very quickly. Carbonic acid is a mild acid, and with the advent of the Insta-Flow device, we have found that the reduction of shoulder pain is, in fact, not due to any carbonic acid changes that would be suspected to cause this. In actuality, it’s the damage to the tissue and the release of the biochemical active prostaglandin material that is reduced, because the cells are not damaged and there is no release of these materials to cause pain."

Dr. Larry Demco: "One of the major problems in laparoscopy, both surgically and post-operatively, is the shoulder pain. Has any study showed how effective it has been in reducing the incidences of shoulder tip pain or the duration of the shoulder tip pain?"

Dr. Douglas Ott: "There have been two studies that have shown that using heated hydrated gas reduces post-operative pain in general, and specifically to the shoulder, and that using the heated, hydrated gas has proven to be efficacious. There are additional studies that are not published yet that have shown that there is a reduction in the duration and in the severity of the pain, too. These studies suggest that if there is any shoulder pain, it is only of transient nature and requires less or no analgesia to correct the problem."

Dr. Larry Demco: "I’ve used this Insta-Flow device myself, and my patients have actually been awake during the procedures. We found quite a dramatic difference and have been able to increase the amount of gas we can use up to 600 cc’s mor