The Influence Of Preoperative Oral Health On Postoperative Microbial Colonization In Lower Respiratory Tract Of The Patients Underwent Open-heart Surgery And Study On The Effects Of Oral Decontamination Intervention

ObjectivesTo investigate preoperative plaque and its influence factors of the patients whounderwent open-heart surgery with mechanical ventilation time less than24hours; andexplore the influence of microorganisms colonized in lower respiratory tract onventilator-associated pneumonia; and investigate influence factors of microbialcolonization in lower respiratory tract.To study the effects of electrolyzed-oxidizing water （EOW） used for oropharyngealdecontaminant preoperatively on colonization with microorganisms in lower respiratorytract postoperatively of the patients who underwent open-heart surgery with mechanicalventilation time less than24hours.MethodsA prospective survey was conducted from November2010to April2011among thepatients who underwent open-heart surgery with mechanical ventilation time≤24hoursin the cardiovascular sugery department of a tertiary A level general hospital in Anhuiprovince. Demographic and perioperative clinical data of the patients was collected andrecorded. And dental plaque was detected on the day before surgery with Tureskymodification of Quigley and Hein plaque index technique. Lower respiratory tractsecretion samples were collected at the time of extubating postoperatively and cultured within2hours. Multivariate logistic regression model was performed to analyzeinfluence factors of preoperative dental plaque and microbial colonization in lowerrespiratory tract. And the incidence of ventilator-associated pneumonia after extubatingwas investigated.The clinical randomized controlled trial was conducted from May2011to September2011among the patients who underwent open-heart surgery with mechanical ventilationtime≤24hours in the cardiovascular sugery department of a tertiary A level generalhospital in Anhui province. From the day before surgery, EOW and sterilized water wasgiven to the patients of study group and those of control group to rinse their mouth,respectively, and100ml each time and4times in total. Oropharyngeal swab sampleswere collected and cultured before the first rinsing and five minutes after the last rinsing.Lower respiratory tract secretion samples were collected at the time of extubatingpostoperatively and cultured within2hours. Microbial colonization in oropharynx andin lower respiratory tract was statistically compared between the two groups. Besides,the incidence of ventilator-associated pneumonia after extubating and side effects ofEOW were observed and recorded.Results178patients were included in the prospective survey. Of them,55.1%were women, themean age was46±13years, the mean BMI （Body Mass Index, BMI） was21.7±2.8, andthe median mechanical ventilation time was18（13,22） hours. The preoperative plaqueindex （PLI） score was range1.4⁴.8, mean3.0±0.7, and56.2%patients were≥3.0.Multivariate logistic regression analysis disclosed that there were significant correlationbetween preoperative PLI of the patients and profession as farmer （OR=3.148, OR95%CI:1.553⁶.383, P=0.001）, the age≥60years （OR=3.041, OR95%CI:1.107⁸.354, P=0.031）, and with smoking history （OR=2.639, OR95%CI:1.264⁵.509, P=0.010）.The rate of microbial colonization in lower respiratory tract was29.2%（52/178）,and VAP incidence was2.2%（4/178）. The VAP incidence was higher of the patientswith microbial colonization in lower respiratory tract than those with microbial-free inlower respiratory tract （4/52VS0/126,x_c²=6.723, P=0.010）. Multivariate logisticregression analysis disclosed that preoperative PLI≥3.0was the independent risk factorof microbial colonization in lower respiratory tract of the patients （OR=23.828, OR95%CI:5.555102.215, P<0.001）.95patients （44patients in study group and51patients in control group） were includedin the clinical randomized controlled trial. The number of the patients withintraoperative and postoperative blood transfusion≥1500ml was more in study groupthan in control one （P=0.007）, and other baseline data was balanced between the twogroups.The amount of microorganisms colonized in oropharynx was similar between the twogroups before intervention （Z=1.386, P=0.166）, and was less in study group than incontrol one after intervention （Z=5.867, P<0.001）, and was less after intervention thanbefore intervention in each group （Z=5.498, P<0.001; Z=2.111, P=0.035）. Potentialrespiratory pathogens colonized in oropharynx were isolated from16patients （9instudy group VS7in control group, χ₂=0.764, P=0.382） before intervention, and isolatedfrom8patients （1in study group VS7in control group, χ₂=4.018, P=0.045）.The rate of microorganisms colonized in lower respiratory tract was21.1%（11.4%instudy group VS29.4%in control group, χ₂=4.629, P=0.031）. The amount ofmicroorganisms colonized in lower respiratory tract was less in study group than incontrol one （Z=2.180, P=0.029）. One patient developed VAP in control group and no patient developed VAP in study one. No side effect of EOW has been observed duringthe study.ConclusionAge, profession and smoking history were the influence factors of preoperative PLI ofthe patients who underwent open-heart surgery with mechanical ventilation time lessthan24hours. The VAP incidence was higher of the patients with microbialcolonization in lower respiratory tract than those with microbial-free in lowerrespiratory tract. Preoperative PLI≥3.0was the independent risk factor of microbialcolonization in lower respiratory tract of the patients.EOW used for oropharyngeal decontaminant preoperatively could effectively reduce theamount of microorganisms colonized in oropharynx and in lower respiratory tractpostoperatively, which could reduce the risk of developing VAP.