EFFECTS OF OPEN-HEART-SURGERY ON ORAL MUCOUS HOST-DEFENSE SYSTEMS

Background: The immune response is affected by anaesthesia and surgery . This study was carried out on the effects of open heart surgery on t he oral mucous host defence system, which is part of the common mucosa l immune system. Methods: Amylase, nonimmunological (lysozyme, myelope roxidase, hypothiocyanite and thiocyanate) and immunological (IgA, IgG , and IgM) mucous host defence factors as well as oral bacterial flora were determined in the saliva of 18 patients undergoing open heart su rgery preoperatively and on the 2nd, 3rd, and 7th postoperative days. To assess the specificity of the changes, the salivary flow rate and t otal protein content were also determined. Results: Stimulated salivar y flow decreased from 1.8 (1.3-2.2) ml/min (median; 25th and 75th quar tiles) to 0.4 (0.3-0.5) ml/min by the 2nd postoperative day and to 0.4 (0.2-1.0) ml/min by the 3rd postoperative day (P<0.001). Amylase, lys ozyme, myeloperoxidase, total salivary peroxidase and thiocyanate leve ls increased, whereas hypothiocyanite levels decreased postoperatively (P<0.01-0.001). Their total secretion rate, however, was reduced (P<0 .05-0.001) owing to the lowered salivary flow rate. IgG and IgM concen trations were raised on the 2nd, 3rd and 7th postoperative days (P<0.0 5-0.001), and IgA concentrations on the 2nd postoperative day (P<0.05) . The total secretion of IgG and IgM as well as their salivary concent rations in relation to total protein concentrations also increased. Th e number of salivary anaerobically growing bacteria decreased postoper atively (P<0.01), but the number of salivary streptococci remained una ffected. Conclusions: Open heart surgery decreases the salivary secret ion of nonimmunological host defence factors and increases the salivar y secretion of IgA, IgG and IgM.