Detecting aspiration associated with tube feedings

描述：（由申请人提供）拟议研究的最终目标是提高机械通气（MV）管饲患者的安全性。这一组患者有吸入反流胃内容物的高风险，其有害后果包括短暂性低氧血症、化学性肺炎和可能危及生命的院内肺炎。在实践环境中努力及早发现愿望，以便能够采取干预措施，防止发病率和死亡率。然而，临床医生不确定如何做到这一点，因为目前可用的床边检测愿望的方法是不可靠的。本研究（1999年8月1日- 2002年7月31日）在动物模型中测试了一种基于胃蛋白酶的实验室检测方法，发现该方法具有高度的敏感性和特异性。初步研究表明，实验室分析可以检测胃蛋白酶（胃内容物吸入的代理）在气管分泌物中从危重病人的管饲吸入。为了确定气管分泌物中胃蛋白酶对肺炎发展的预测程度，将计算每日临床肺部感染评分。管饲MV患者管理的另一个问题是不确定如何评估胃肠道（GI）运动明显减慢，这是一种易发生误吸的情况。尤其有问题的是，很难确定何时胃肠蠕动减慢的指标，如胃肠残余体积大，足以保证暂时停止喂养。因此，喂养经常被不必要地停止，导致热量摄入显著减少。因此，本研究的另一个目的是确定胃肠道运动减慢的迹象，这些迹象最能预测胃内容物的渴望。其他目的是检查吸入危险因素对气管分泌物胃蛋白酶检测的影响，以及肺炎危险因素对肺炎发展的影响。本研究是一项前瞻性描述性研究，纳入680名危重病人，在前3天每天24小时进行监测，以评估吸入气管分泌物中的胃蛋白酶、胃肠道对管饲不耐受的迹象（胃肠道残留体积大、肠音缺失和呕吐）以及误吸和肺炎的危险因素。此外，在管饲的前4天每天计算临床肺部感染评分。患者将从一个一级创伤中心的5个重症监护病房招募。数据收集将在24个月内进行，数据将通过逻辑回归和多元线性回归进行分析。

DESCRIPTION: (provided by applicant) The ultimate goal of the proposed study is to increase the safety of mechanically ventilated (MV) tube-fed patients. This group is at high risk for aspiration of regurgitated gastric contents with deleterious consequences including transient hypoxemia, chemical pneumonitis, and potentially life-threatening nosocomial pneumonia. Efforts are made in practice settings to detect aspirations early so that interventions can be initiated to prevent morbidity and mortality. However, clinicians are unsure about how to accomplish this since currently available bedside methods to detect aspirations are unreliable. A laboratory method of detecting aspirations based on pepsin was tested in an animal model in the current study (8/1/99-7/31/02) and found to be highly sensitive and specific. Preliminary studies have indicated that the laboratory assay can detect pepsin (a proxy for the aspiration of gastric contents) in tracheal secretions suctioned from critically ill tube-fed patients. To determine the extent to which pepsin in tracheal secretions predicts the development of pneumonia, daily Clinical Pulmonary Infection Scores will be calculated. Another problem in the management of tube-fed MV patients is uncertainty about how to assess for significantly slowed gastrointestinal (GI) motility, a condition that predisposes to aspiration. Especially problematic is difficulty in determining when indicators of slowed GI motility, such as large GI residual volumes, are of sufficient magnitude to warrant temporary withholding of feedings. As a result feedings are often withheld unnecessarily, leading to significantly reduced caloric intake. Therefore, another aim of the proposed study is to identify the signs of slowed GI motility that are most predictive of aspirations of gastric contents. Additional aims are to examine the effect of risk factors for aspiration on the detection of pepsin in tracheal secretions as well as the effect of risk factors for pneumonia on the development of pneumonia. The proposed work is a prospective, descriptive study of 680, critically ill, tube-fed patients who will be monitored 24 hours a day for the first 3 days of tube feedings to assess for: pepsin in suctioned tracheal secretions, signs of GI intolerance to tube feedings (large GI residual volumes, absence of bowel sounds, and presence of vomiting), and risk factors for aspiration and pneumonia. In addition, Clinical Pulmonary Infection Scores will be calculated daily for the first 4 days of tube feedings. Patients will be recruited from 5 intensive care units at a Level I trauma center. Data collection will occur over a 24-month period and the data will be analyzed by logistic regression and multiple linear regression.