Effects of anaesthesia using endotracheal intubation or the laryngeal mask airway, or spinal anaesthesia, on oral mucosal host defences during minor surgery.

Background:  Oral mucosal host defences are altered after anaesthesia and surgery. The effects of endotracheal intubation (ET) and the use of the laryngeal mask airway (LMA) on oral mucosal host defences after minor surgery were compared. Methods:  Immunological (immunoglobulin A (IgA), IgG and IgM) and non-immunological (myeloperoxidase, total peroxidase, thiocyanate) oral host defence factors, and amylase and protein concentrations, were measured from saliva pre-operatively and on the first post-operative day in 60 ASA I–II patients undergoing minor surgery. The patients underwent general anaesthesia using oral ET or LMA. Spinal anaesthesia (S) was used as control. Serum IgG, IgM and IgA concentrations were determined. Results:  Protein-related salivary secretion of amylase and salivary concentration of IgM showed the only statistically significant overall differences between the groups. By contrast, changes were observed within the ET group in the salivary flow rate, protein concentration, amylase activity and immunological host defence factors. Some changes were also observed in the LMA group, but none in the S group. Most non-immunological test values did not change within any of the groups. Conclusions:  ET and LMA induced similar oral mucosal host defence responses. There were, however, observations in this study that indicated a stronger response during ET than when LMA was used.