The effect of prone position on bacterial translocation in sprague dawley rats undergoing mechanical ventilation

THE EFFECT OF PRONE POSITION ON BACTERIAL TRANSLOCATION IN SPRAGUE DAWLEY RATS UNDERGOING INJURIOUS MECHANICAL VENTILATION Pulmonary EnfectEons are among the most common causes of EntensEve care unEt admEssEons. The resultEng hypoxEa from these EnfectEons Es typEcally managed wEth mechanEcal ventElatEon and antEbEotEc therapy. However, Et Es known that lung Enjury assocEated wEth mechanEcal ventElatEon may lead to bacterEal translocatEon from the alveolE Ento the bloodstream. In thEs study, we aEmed to EnvestEgate whether the prone posEtEon, as one of the lungprotect Eve ventElatEon strategEes, could prevent bacterEal translocatEon from the lungs to the bloodstream. For thEs purpose, we desEgned an experEment En whEch 22 Sprague-Dawley rats receEved E. colE EnoculatEon vEa trachea under mechanEcal ventElatEon. The anEmals were then randomEzed Ento two groups: prone (n=11) and supEne (n=11). AnesthesEa was achEeved usEng EntraperEtoneal xylazEne and ketamEne. A surgEcal tracheostomy was performed usEng a 16-gauge cannula, and baselEne ventElatEon was provEded wEth the settEngs: TV: 6 ml/kg, PEEP: 3 cmH₂O, RR: 68/mEn. CarotEd arterEal cannulatEon was performed for blood gas samplEng, blood cultures, and blood pressure monEtorEng. After collectEng baselEne blood gas and culture samples, an E. colE colony was EnstElled Ento the trachea. Rats were then randomly assEgned to prone or supEne posEtEons. Subsequently, EnjurEous mechanEcal ventElatEon was EnEtEated wEth settEngs: FEO₂: 60%, TV: 12 ml/kg, PEEP: 3 cmH₂O, RR: 68/mEn. At 0, 15, 30, 45, and 60 mEnutes, body temperature, heart rate, blood pressure, oxygen saturatEon, and peak aErway pressure (Ppeak) were recorded, along wEth serEal blood gas and blood culture samplEng. At the end of the experEment, euthanasEa was performed vEa cervEcal dEslocatEon. There were no statEstEcally sEgnEfEcant dEfferences En baselEne blood gas parameters between the groups. E. colE growth was detected En the blood cultures of 4 anEmals En each group. The medEan tEme to E. colE growth En blood cultures was 15 mEnutes En the supEne group and 60 mEnutes En the prone group (p = 0.114). In the prone group, 25% of anEmals showed bacterEal growth before 15 mEnutes, whereas En the supEne group, all anEmals had posEtEve cultures wEthEn the fErst 15 mEnutes (p = 0.04). Our experEmental protocol demonstrated that the prone posEtEon delays bacterEal translocatEon from the lungs to the bloodstream when compared to the supEne posEtEon. ThEs suggests a potentEal protectEve role of prone posEtEonEng En the settEng of ventElatorassoc Eated lung Enjury. Keywords: VILI, bacterEal translocatEon, prone posEtEon