2 The technology

Description of the technology

2.1 HumiGard (Fisher and Paykel Healthcare) is designed to humidify and heat carbon dioxide (CO2) gas, which is routinely used to fill the peritoneal cavity during laparoscopic abdominal surgery. The intention is to reduce the negative effects associated with the use of dry, unwarmed CO2 gas, namely tissue desiccation and intra-operative hypothermia. HumiGard is designed to be used both independently and in addition to other warming measures that are applied to the external body surfaces and extremities, such as forced air warming. HumiGard comprises a humidifier and consumable tubing set. It humidifies and warms the CO2 by passing the gas over a reservoir of water. The heated, humidified gas is then passed along a sterile tube for delivery into the abdominal cavity through a needle cannula. HumiGard can also be applied to open surgical wounds using a bespoke patient interface diffuser to effectively immerse the open surgical wound cavity in warmed, humidified CO2 gas.

2.2 HumiGard received a class IIa CE mark in April 2013. It is indicated for use in laparoscopic or open abdominal surgery when CO2 insufflation gas is used.

2.3 The list prices (excluding VAT) for the components of HumiGard are as follows.

  • Capital costs:

    • MR860AEU humidifier: £895.

  • Consumables:

    • For laparoscopic surgery: ST310 humidified and heated tubing kit: £75 per patient.

    • For open surgery: ST310 humidified and heated tubing kit plus VITA diffuser (ST300 DF): £99 per patient.

2.4 The claimed benefits of HumiGard in the case for adoption presented by the company are:

  • Decreased incidence of intra-operative and post-operative hypothermia through less evaporative cooling.

  • Decreased incidence of surgical site infections because of improved intra-operative temperature maintenance.

  • Improved post-operative recovery and faster discharge.

  • Reduced overall costs as a result of better patient outcomes including fewer surgical site infections, less time spent in hospital for surgery, and less time in post-operative recovery.

Current management

2.5 The NICE guideline on hypothermia recommends that all patients intended for surgery be assessed for risk of perioperative hypothermia. All patients should receive warmed intravenous fluids and blood products; patients identified as being at higher risk should be warmed intraoperatively using a forced air warming device, as should any patient having anaesthesia for more than 30 minutes. Regular temperature measurement is recommended before, during and after surgery, and forced air warming is recommended for any patient whose core temperature drops below 36°C.

2.6 NICE's hypothermia guideline relates to the general prevention of hypothermia during surgery and does not make any specific recommendations about the warming of insufflation gas. Unwarmed, dry insufflation gas is used routinely in laparoscopic surgery.

2.7 NICE medical technologies guidance on the Inditherm patient warming mattress recommends this device as a cost-effective alternative to forced air warming.

  • National Institute for Health and Care Excellence (NICE)