Hysteroscopy - Fluid Overload

August 25, 2006

OBGYN.net Conference CoverageFrom American Association of Gynecological LaparoscopistsAtlanta, Georgia, November, 1998

Roberta Speyer: "This is Roberta Speyer reporting from the AAGL conference in Atlanta. I'm talking to Professor Stephen Corson, from Thomas Jefferson University. You had a wonderful presentation this morning about fluid overload and how to avoid that. Would you tell us a little bit about what was covered and some ideas of what's going on in that area now?"

Dr. Stephen Corson: "Hysteroscopy is usually a very safe procedure but because fluid is used to distend the uterus, there's a risk of intravasation, and the fluid medium then gets into the vascular tree causing hypervolemia. If it is a salt-free solution as is the case when electrosurgery is employed, the patient gets hyponatremia. There have been a number of deaths that have been caused by large deficits between what the doctors put into the patient and what comes out. In order to try to avoid and minimize the danger, various systems have been devised to allow the doctors to accurately measure in real time the amount of fluid that goes in and that which is retrieved. And additionally, these systems allow the doctors to preset and maintain a safe operating pressure."

Roberta Speyer: "So is this really the most dangerous part of doing this type of procedure?"

Dr. Stephen Corson: "In terms of the overall morbidity - the answer is yes. A hysteroscopic related room air embolism is usually more dramatic in that when it happens it's almost always fatal but it happens quite rarely. On the other hand, fluid intravasation problems occur more commonly."

Roberta Speyer: "Do they occur more commonly because of the amount of skill of the physician or the amount of times that they have done the procedure? How does a physician avoid this and how does a physician assess this as a risk to their adopting some of these procedures?"

Dr. Stephen Corson: "As with other complications there tends to be a bimodal distribution in the beginning as one is gaining experience. There's the experience factor but later when one becomes more adept and comfortable, he or she may start to do cases that are more demanding. A large vascular myoma of a submucous variety with a lot of blood vessels in it presents a challenge so that the experienced physician can also get in over his head as well. The systems are designed, however, to really keep you out of trouble by alerting you when your intravasation has reached a liter - meaning you put a liter of fluid more into the patient then that which has come out, and additionally allowing you to operate at safe pressures is helpful. If your pressure is too low in the uterus - the bleeding will obscure your visual field. On the other hand, if your pressure is too high - then you've opened vessels, and you're going to push fluid into the vascular tree. The ideal is to operate just around the point of mean arterial pressure at which point the fluid exchange in either direction is very low."

Roberta Speyer: "How would you recommend that a physician that was concerned about this best educate themselves so that they stay out of trouble?"

Dr. Stephen Corson: "I think going to courses and to meetings, and reading about this is very helpful but you really need to have the proper piece of equipment in your operating room. The 3 L bags as they come from the manufacturer are a plus or minus 10% with respect to volume. So that even if you have a nursing staff which is very assiduous in its efforts to measure the volume, because of the fact that they don't really know what their starting out with - it's impossible. The monitoring systems don't use volumetric measurements, they use mass so the bag is weighed, and the Foley canister which collects the fluid coming from the patient is weighed. It's much more accurate of a system than volumetric, a simple chip subtracts the difference, and you get a constant readout. So this is a circumstance where a good physician can still get into trouble because he or she doesn't have the right instrumentation."

Roberta Speyer: "So it's really a technology issue?"

Dr. Stephen Corson: "To a great degree, yes, but the doctor has to understand the underlying physiology."

Roberta Speyer: "So do you see that the industry is responding to this by the products that are coming out now are being created in such a way as to make this problem less?"

Dr. Stephen Corson: "I believe so, I've designed one system which is commercially sold, and other people have designed systems so there's been a good deal of thought…"

Roberta Speyer: "Why don't you tell us a little bit about your system?"

Dr. Stephen Corson: "Our system is called the "DOLPHIN," and it's marketed by Circon ACMI, and that allows you to preset your pressures. There are warning alarms that tell you when the patient has a deficit of a liter. There's a separate audible and visual alarm which tells the nurse when the reservoir bag has to be changed. And there's a third alarm system with a different tone that tells the nursing staff when the collecting canister has to be changed. So it's all pretty automated, the nurses love it because they don't have to run around in a darkened room trying to measure input and output, and the doctors like it too. It gives everybody a sense of safety."

Roberta Speyer: "So with equipment like this and other companies I'm sure have also worked on these types of things - but with equipment like the DOLPHIN that's really able to assist you, you still need the skill of the physician and the staff still needs to understand, but you are putting in a lot of safety checks. Is that really what's happening?"

Dr. Stephen Corson: "You can never engineer the doctor out of the equation, particularly when you're talking about surgery, so the skill of the physician is certainly still the foremost factor. But the role, I think, of industry and the role of technology is to allow the doctor to do what the doctor has to do in a environment which is as safe as possible. Additionally, this probably decreases the need for an extra circulating nurse in the operating room, so it winds up to be a cost saver as well."

Roberta Speyer: "I guess over a period of time that would make a big difference - human cost being really the most expensive cost in the surgery, is it not?"

Dr. Stephen Corson: "Today it is, yes."

Roberta Speyer: "I think that's very interesting, and I think the doctors on OBGYN.net will appreciate you sharing this with us. Thank you very much, Dr. Corson."

Dr. Stephen Corson: "Thank you."