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OBGYN.net Conference CoverageFrom American Association of Gynecological LaparoscopistsOrlando, Florida, November 2000
Dr. Hugo Verhoeven: "My name is Hugo Verhoeven from the Center for Reproductive Medicine in Germany, and I'm reporting from the Global Congress on Gynecologic Endoscopy in Orlando, Florida. It is a real honor for me talking this afternoon with Larry Demco who is an Associate Clinical Professor at the University of Calgary in Canada and one of the leaders in the field of laparoscopy. Larry, I heard one of your lectures this afternoon, you are doing quite a lot of the procedures under local anesthesia. That must be quite painful for the patients, what are you doing to make it less painful for the patients?"
Dr. Larry Demco: "One of the leading problems with all the patients that undergo a laparoscopy whether it's done under a local anesthetic or a general anesthetic has been the development of shoulder tip pain either during the procedure or once they wake up from a general anesthetic. They are stricken for a day or so with the shoulder tip pain and this can be quite distressing for the patient. With the problem of the shoulder tip pain, we had several theories of exactly why it occurred. For years we thought it was due to the carbon dioxide gas that we use. This reacts with the water that's in the peritoneal fluid causing carbonic acid to be formed, This causes a chemical irritation to the diaphragm, which in turn causes the shoulder tip pain. New evidence suggests that the shoulder pain is due to cellular death of the cells lining the peritoneum and on the bowel. The cellular death comes from the changes in temperature and drying that occurs in the abdomen when a patient undergoes laparoscopy."
Dr. Hugo Verhoeven: “That means whatever medium you use for distention you will always have shoulder pain because the temperature of the gas or the fluid is too low.”
Dr. Larry Demco: “That’s correct, we experimented with helium, nitrous oxide, and argon and they all produced the same or similar effect.
Dr. Hugo Verhoeven: “What about room air?”
Dr. Larry Demco: "Room air does not cause shoulder pain, and we always wondered why that occurred. We currently do not use room air because it can cause an air embolism and supports combustion. We noticed that there was something about room air that was completely different than the carbon dioxide in the cylinder. When we looked at this more closely, we saw that room air has humidity and the interior abdominal cavity also has humidity of approximately 95%. The humidity of the carbon dioxide gas is .0002% and as a result, when it comes out, it's a very drying effect. When you combine that with the principle that when the gas expands, it cools, these two effects cause the cellular death which then leads to the release of chemicals from the cells and this causes the shoulder tip pain."
Dr. Hugo Verhoeven: “May I ask you, maybe it’s a stupid question but the pain is always on the left side, and most of the time the pain is in the left shoulder. Why is it only on one side if it’s caused by cellular death?”
Dr. Larry Demco: "Nobody really can answer that. Patients have told us that left -right really doesn't occur in everyone. A study that we did last year showed that 18% of patients are opposite; if you touch the abdomen on the left side, they'll say your touching the right. Another similar condition is dyslexia where people write letters the opposite way. This is due to miscommunication between the eye and the brain. We see there's a similar miscommunication in the abdomen and the brain. So it's quite interesting to try to answer your question of why the pain is sensed on the left, but it is best to say that it is sensed in the main brain and not at the local level."
Dr. Hugo Verhoeven: “Let’s now go back to the humidity and the temperature of your distension medium that you’re using. How can you change the temperature of the CO2 gas that you’re using, and how can you put some more humidity in it? How do you do that?”
Dr. Larry Demco: "The initial work was done where they started to heat the gas and this has been attempted for several years, Now there is a new device called 'Insuflow' that attaches to any insufflator and it heats the gas up to body temperature. It also adds the humidity right at the entrance point to where you attach it to your trocar. The gas that enters is now humidified and it's the proper body temperature so it does not cause the effects that we just mentioned. The spin off from this, as our paper showed today, is the patients now need less IV sedation during even a local laparoscopy and because the patients are more comfortable during the laparoscopy, The tolerance for awake laparoscopy markedly increases. The advantage to the physician is that he may now use volumes of gas of 2 to 3 liters and now works in the same similar laparoscopic conditions that he had when it was under general anesthetic. All these things have aided to the advancement of laparoscopy under a local. The patient on the other side, since she's not having pain during the procedure, as you'd expect, does not have pain when the procedure is over since it reduces the shoulder tip pain to less than 20% from 80%. As a result, our biggest problem came to us not in the operating room but for the patient in post-op. This has really helped the whole situation because we may take fifteen minutes to do a tubal ligation but it takes them two hours to get out of the recovery room. When they're not having any pain they want to go immediately, they want to get dressed and just leave shortly after the procedure."
Dr. Hugo Verhoeven: “So if you heat the distension medium and you add some humidification, the frequency of shoulder pain will be lower.”
Dr. Larry Demco: “Correct.”
Dr. Hugo Verhoeven: “But shoulder pain lasts for a certain amount of days, is it also reduced?”
Dr. Larry Demco: “Yes, the average person will see it for approximately a full day. Now if they happen to be the 20% that still has the shoulder tip pain, it’s usually resolved within six hours and the amount of medication that they use for it is markedly reduced. We still do have the occasional patient that does go for a day or so but the numbers are markedly reduced.”
Dr. Hugo Verhoeven: “Are there other positive side effects of humidification and heating besides just reducing the shoulder pain for the patient?”
Dr. Larry Demco: "The other thing is on a longer procedure there¹s a risk of ileus where the bowel stops peristalsis and this is due to cellular death on the bowel itself or the cells on the surface of the bowel and heating and humidifying prevents your ileus formation. There is also work to suggest that adhesion formation may also be reduced. This is actually the only one of a few devices that has very little to do with the surgery in a sense that the only benefit for the surgeon is that the lenses don¹t fog up but for the patient they don¹t reduce their temperature during the procedure so that helps them there. Then the post-operative shoulder tip pain is virtually eliminated, and as a result, we see a big step. To put it in proportion, with laparotomy to laparoscopy, we saw a big benefit for the patient there and now we're going from laparoscopy with pain to laparoscopy without which is another giant step."
Dr. Hugo Verhoeven: "My final question, every technique has its limits even if you are reducing the shoulder pain, what procedures can you do under local anesthesia? Where are your borders? Are you just doing diagnostic procedures or are you also doing tubal ligations, for instance, or adhesiolysis?"
Dr. Larry Demco: "Actually, right now this new procedure is going to expand the current list and the current list is for Endometriosis, for infertility investigation, and for pain mapping those patients that have trouble identifying the type of pain that they have, and where the lesions causing the pain are. We're doing it for lysis of adhesions and for tubal ligations. I think the next big step is to start doing Awake laparoscopic procedures in the Emergency Room and the ICU. If you're asking in the future can we do a laparoscopy under local for a hysterectomy - we say no, not yet, we've got a long future ahead of us."
Dr. Hugo Verhoeven: “Maybe under acupuncture or something like that. Larry, thank you very much.”
Dr. Larry Demco: “Thank you very much.”