Humidification during laparoscopic surgery: overview of the clinical benefits of using humidified gas during laparoscopic surgery

Abstract

PurposeThe peritoneum is the serous membrane that covers the abdominal cavity and most of the intra-abdominal organs. It is a very delicate layer highly susceptible to damage and it is not designed to cope with variable conditions such as the dry and cold carbon dioxide (CO2) during laparoscopic surgery. The aim of this review was to evaluate the effects caused by insufflating dry and cold gas into the abdominal cavity after laparoscopic surgery.MethodsA literature search using the Pubmed was carried out. Articles identified focused on the key issues of laparoscopy, peritoneum, morphology, pneumoperitoneum, humidity, body temperature, pain, recovery time, post-operative adhesions and lens fogging.ResultsInsufflating dry and cold CO2 into the abdomen causes peritoneal damage, post-operative pain, hypothermia and post-operative adhesions. Using humidified and warm gas prevents pain after surgery. With regard to hypothermia due to desiccation, it can be fully prevented using humidified and warm gas. Results relating to the patient recovery are still controversial.ConclusionsThe use of humidified and warm insufflation gas offers a significant clinical benefit to the patient, creating a more physiologic peritoneal environment and reducing the post-operative pain and hypothermia. In animal models, although humidified and warm gas reduces post-operative adhesions, humidified gas at 32 °C reduced them even more. It is clear that humidified gas should be used during laparoscopic surgery; however, a question remains unanswered: to achieve even greater clinical benefit to the patient, at what temperature should the humidified gas be when insufflated into the abdomen? More clinical trials should be performed to resolve this query.

Changes in the coelomic microclimate during carbon dioxide laparoscopy: morphological and functional implications

“…The cold, dry CO 2 stream from the pressurized gas insufflator has a velocity of up to 20-30 m/s [2,3,5,15] and shows some similarities to the polar jetstream of the Northern hemisphere. Both have a rapid, relatively narrow, turbulent flow and contain dense, cold, dry gas.…”

“…This means that CO 2 gas is readily absorbed and rapidly excreted. Thus the perioperative risks of gas embolism, retained gas, pneumothorax and potentially pain are less with CO 2 insufflation compared to air [5][6][7].…”

“…As it passes the throttle valve on the cylinder head the CO 2 vaporizes, expands and cools as a result of the Joule-Thomson effect. When it enters the coelom via the gas insufflator, the relative humidity of introduced dry CO 2 gas is 0.0002 % [5], with a temperature of 20°C and a high velocity [2,5,9]. The use of cold-dry CO 2 gas causes a number of local effects on the peritoneal mesothelium, as well as systemic effects in the subject [5].…”

“…When it enters the coelom via the gas insufflator, the relative humidity of introduced dry CO 2 gas is 0.0002 % [5], with a temperature of 20°C and a high velocity [2,5,9]. The use of cold-dry CO 2 gas causes a number of local effects on the peritoneal mesothelium, as well as systemic effects in the subject [5]. These can be observed at a macroscopic, microscopic, cellular and metabolic level [2][3][4][5][6][7][8][9][10][11][12][13][14][15].…”

“…Local effects include evaporative cooling, oxidative stress [10][11][12], desiccation of mesothelium, disruption of mesothelial cell junctions and glycocalyx, diminished scavenging of reactive oxygen species (ROS), decreased peritoneal blood flow, peritoneal acidosis, peritoneal hypoxia or necrosis, increased ROS production, exposure of the basal lamina and extracellular matrix (ECM), lymphocyte infiltration, and generation of prostaglandins and peritoneal cytokines such as IL-1, IL-6, IL-8 and TNFα [2,5,13,14]. Factors that increase evaporation include an increase in gas flow ("wind") or surface area, or a decrease in humidity.…”