神经重症患者胃液 pH 值监测与医院获得性肺炎的相关性

Relationship bewteen gastric pH and hospital-acquired pneumonia in neurological intensive care unit patients

目的：通过监测神经重症患者胃液pH值，探讨其与医院获得性肺炎的相关性，以及对胃腔定植菌和肺炎病原学的影响。方法本研究为前瞻性队列研究。研究对象为2014年10月1日到2015年5月1日我院神经内科重症监护病房收住的72例接受连续性管饲饮食的神经重症患者。动态观察所有入组患者的胃液pH值，并留取胃腔、口咽部及上呼吸道标本，进行病原菌定量培养。根据入院期间是否新发医院获得性肺炎，将患者纳入新发感染组（感染组，40例）或无新发感染组（对照组，32例），比较两组患者胃液pH值及病原菌。结果感染组入院第1天空腹胃液pH值[6.4（5.4，6.4）]高于对照组[5.4（2.5，6.4）， Z＝－2.37， P＝0.01]，感染组入院第1、2天餐后胃液pH值[6.3（5.4，6.7）、6.4（5.5，6.7）]高于对照组[5.6（3.1，6.4）、5.6（3.3，6.4）， Z＝－2.53、－2.15，均P＜0.05]；感染组胃腔病原菌定植检出率达60.8％（42／69，均为标本数），高于对照组但差异无统计学意义；胃液 pH ＞4时，感染组胃腔内革兰阴性菌分离率（63.6％，28／44）比对照组（35.7％，10／28）明显上升（χ2＝5.323，P＝0.021）；感染组中7例（17.5％）患者上呼吸道病原菌与胃腔及口咽部培养菌群一致。结论神经重症患者胃液pH值增高，使胃腔定植菌特别是革兰阴性杆菌定植增加，可能是引起医院获得性肺炎的重要因素。

Objective To explore the relationship between gastric juice pH and hospital-acquired pneumonia （ HAP） , the gastric bacterial colonization and etiology of HAP in neurologic intensive care unit patients by monitoring gastric juice pH value.Methods From October 2014 to May 2015, consecutive seventy-two tube feeding patients admitted in the Department of Neurology Intensive Care Unit in Xijing Hospital were enrolled in this research.The type and concentration of pathogens from gastric contents were collected, while samples from upper respiratory tract and pharynx were detected dynamically at the same time.Results （1）The group with new onset HAP was higher in gastric juice pH （6.4（5.4,6.4） vs 5.4 （2.5, 6.4）, Z=-2.37, P=0.01）; （2） The isolation rate of colonized bacteria in gastric cavity was associated with the pH of gastric juice , achieving 60.8% （ 42/69 ） in HAP group; （ 3 ） When the gastric juice pH was 〉4, the isolation rate of Gram-negative bacilli in gastric cavity obviously increased （63.6%（28/44） vs 35.7%（10/28）,χ2 =5.323, P=0.021）; （4）The same pathogens were found in stomach-pharynx-upper respiratory tract in 7 cases （ 17.5%） of the total 40 HAP patients.Conclusion Increased gastric juice pH was associated with gastric colonization , especially Gram-negative bacilli , and may lead to a higher incidence of new onset HAP in patients on enteral feeding.