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Are Your Patients Full of Hot Air?
They should be. Heating and humidifying CO2 reduces post-op pain and promotes faster recoveries.
Larry Demco
Publish Date: December 1, 2008   |  Tags:   General Surgery

Heating and humidifying insufflation gases prevents cellular death of the peritoneum, resulting in less post-op pain, faster recoveries and quicker discharges. Despite such benefits, you may not be warming CO2. Cost may be a deterrent. Disposable devices that treat CO2 typically add $75 to $100 in case costs. Here's what you might be missing out on.

1. Faster discharge for shorter cases.
Heating and humidifying carbon dioxide during short procedures performed under local, like tubal ligation, greatly increases case efficiency. Patients insufflated with straight CO2 might spend two hours in recovery before meeting discharge criteria after a 15-minute procedure. Patients insufflated with heated and humidified CO2, however, experience less post-op discomfort and are often ready for discharge soon after the case ends.

2. Improved efficiency for longer cases.
Treating insufflation gases also improves clinical outcomes of longer cases. Pumping heated CO2 instead of cold gas into the abdomen helps maintain a patient's core body temperature, eliminating the need for patient warming devices. Treating insufflation gases also might allow the use of local sedation instead of general anesthesia for select cases. Patients under a local who receive straight CO2 sometimes experience breathing difficulties, necessitating a mid-procedure switch to general anesthesia. Using heated and humidified gas reduces that risk.

3. Reduced shoulder pain.
We've all had patients wake from abdominal laparoscopic procedures complaining of right shoulder pain. For years, many believed CO2 insufflating the abdomen reacted with water in the peritoneal fluid to form carbonic acid, which in turn caused a chemical irritation in the diaphragm. That theory proved incorrect. Carbon dioxide's humidity level (0.0002 percent) and temperature (21 ?C) are considerably lower than the conditions inside the abdomen. Researchers discovered that CO2 expands and cools when blown into the abdomen, dropping the cavity's internal temperature. The extreme temperature change and drying effect cause cellular death, releasing chemicals from the peritoneum that irritate the phrenic nerve, which transmits pain impulses to the shoulder. Patients typically experience shoulder pain for a full day after surgery.

Gas entering the abdomen after being heated and humidified to normal body levels, however, reduces cellular damage at the peritoneum and bowel, which reduces shoulder pain by as much as 80 percent. If patients happen to experience post-op shoulder pain after being insufflated with treated CO2, the discomfort usually resolves within six hours, and the amount of pain medication they require is significantly reduced. Patients occasionally suffer shoulder discomfort for a full day or more, but that's becoming less common when heated and humidified insufflation gas is used.

Manufacturers may have finally matched insufflation gases to the body's normal temperature. Devices on the market today attach to trocars to heat and humidify gases at the entrance point to the abdomen. For example, one device features a chamber charged with 8cc of sterile water. The chamber heats the insufflation gas to 38.5 ?C (98 ?F) and humidifies it to 95 percent humidity, matching the conditions found inside the abdomen. It can heat and humidify 150L of gas and can be recharged if you need greater gas volumes.

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