COMPARTMENTALISATION OF INFLAMMATORY CYTOKINES AFTER ELECTIVE ORTHOPAEDIC SURGERY

Dr Nicholas Ireland - Anaesthetic Registrar, Waikato Hospital

Immune compartmentalisation helps maintain effective inflammation at a local area of infection or tissue trauma, but helps dampen systemic cytokine activation. Regulation of mediators involved in the response to microorganisms, inflammation and eventual healing must occur differently in local and systemic compartments. A number of investigations have looked at this concept in sepsis, but few in the non-infected setting. We measured gene expression by reverse transcriptase PCR array in peripheral blood and wound site samples of 10 patients undergoing elective orthopaedic surgery for total hip or knee joint replacement. We examined mRNA levels of 24 different cytokines in venous blood and wound drain fluid at 6hs and 24hrs post-operatively, and compared the expression with that found in pre-operative blood samples. We used expression of beta2 microglobulin as the 'housekeeper' gene. We found consistent increases in the expression of Interleukin 1, C5a-receptor, Myloperoxidase, Matrix Metalloproteinase 9, NF-kB and Interleukin 8 in the peripheral blood after surgery. Similar compartmentalised expression was found when comparing wound-site samples with the expression in the blood. We found no mRNA suppression in either venous blood or drain fluid. These results indicate a modest activation of the innate immune system by major orthopaedic surgery, different in pattern to that reported in sepsis. These represent a group of patients that had uneventful recovery. Further work with this technique may be used to compare the effects of regional and general anaesthesia, and may be early indicator of infection.

Time of Presentation:

Monday 5 May 2003 - 1110-1120

Additional Authors:

• Dr Ray Cursons - Department of Biological Sciences, Waikato University, NZ
• Dr Michael Kalkoff - Department of Intensive Care, Waikato Hospital, NZ
• Dr Jamie Sleigh - Department of Anaesthesia, Waikato Hospital, NZ

Biography:

An Anaesthetic Registrar in the 3rd year of training currently living in Hamilton, New Zealand.