Ventilator-associated sinusitis : A clinical investigation into the inflammatory response: Reactive - Infective - Infectious?

Critically ill mechanically ventilated patients regularly have inflammatory reactionsin the paranasal sinuses. Infectious sinusitis, which is difficult to diagnose, mayoccur, mainly in the maxillary sinuses. This study was performed with the objectof improving the knowledge of inflammatory and/or infectious disease. Ultrasound,as an indirect diagnostic facility, was evaluated against visual criteria at endoscopy.Assessments by endoscopy were calibrated with the help of video recordings evaluatedby an expert panel. To improve bacteriological diagnostics of the antra a new techniquefor sampling was developed to reduce contaminations. A routine was set up to identifyfalse positive cultures by comparative quantitative cultures from the antra and thecorresponding passage route. Anaerobic cultures from antral mucosa were made. Correlationsbetween endoscopic and bacteriologic diagnostics were analysed. To find out if antibioticsused in the ICU reach the antra, concentrations were determined by a bio-assay method.As markers of inflammatory diseased antral mucosa, the cytokines lL-6, IL- 12 andthe chemokine RANTES were detcermined by RT-PCR. The expression of the adhesion moleculesICAM-1, VCAM-I, E- and P-selectin was demonstrated by immunocytochemistry. Ultrasound had a low capacity for differential diagnostics. The expert panel verifiedthe reliability of endoscopic assessments. There was an almost perfect concordanceon infectious sinusitis. The endo scopic diagnosis of infectious sinusitis correlatedto positive anaerobic cultures. The rate of false positive cultures was significantlyreduced by the improved sampling technique. Three antra, with positive cultures,were assessed endoscopically as inflammatory reaction without signs of infection.They were thus colonised. The bacterial findings were mostly anaerobic or facultativeanaerobic. The most common pathogens, as previously described, Staphylococcus aureusand Pseudomonas aeruginosa, were only present in gingival cultures or as contaminantsbut not identified as the cause of infection. Different stages of inflammatory diseasewere found in 85%. But only 6% (4 antra) were infectious Sinusitis. Lactobacilluswere monoisolates in 2 out of 3 colonisations. In all infected or colonised antra,mRNA of RANTES was found (p= 0.005). The predominant adhesion molecule expressedin all specimens examined was P-selectin.The antibiotic concentrations in intarcellulartissue were related to the serum levels and thus strongly support an appropriatelocalisation of the drugs included. The four infections diagnosed were empyemas withretained secretion constituting biofilm formations where the bacteria were inaccessibleto antibiotics. In summary, the rate of infectious sinusitis was markedly less in this study comparedto previous publications. The main pathogens of the infections diagnosed also differed.Antral colonisation of bacteria, regarded as nonpathogenic, has not been reportedin mechanically ventilated patients pre viously. Keywords: nosocomial sinusitis, infection, inflammation, bacteriology, cytokines,critically ill patients ISBN 91-628-2616-

Sammanfattningar av projektarbeten. Behörighetsutbildning i försäkringsmedicin 2013

I denna rapport presenteras sammanfattningar från de projektarbeten som genomförts inom ramen för uppdragsutbildningen Behörighetsutbildning i försäkringsmedicin, vid Sahlgrenska akademi