MEASUREMENT OF GLUCOSE IN TRACHEOBRONCHIAL SECRETIONS TO DETECT ASPIRATION OF ENTERAL FEEDINGS

OBJECTIVES: To determine (1) the relationship between results from 2 m ethods to measure glucose in tracheobronchial aspirates, (2) the effec t of blood glucose levels on tracheobronchial glucose levels, and (3) the relationship between results from 2 methods to measure glucose in selected enteral formulas. DESIGN: Descriptive. SETTING: Two midwester n acute-care hospitals, a research laboratory, and a clinical laborato ry. PATIENTS: Sixty-two acutely ill adult subjects with artificial air ways whose secretions required frequent suctioning for therapeutic pur poses; 53 of these 62 patients also required capillary blood glucose m easurements for therapeutic purposes. OUTCOME MEASURES: Glucose concen trations in tracheobronchial secretions, capillary blood, and selected enteral formulas. INTERVENTION: None. RESULTS: Measures of glucose co ntent made on 75 split samples of tracheobronchial secretions by 2 met hods (glucose oxidase reagent strips and a laboratory assay) were high ly correlated (r = 0.94; P <.001) and mean readings were not statistic ally different (P =.17). Sixty-six capillary blood glucose readings ma de within 5 minutes of tracheobronchial suctioning correlated poorly w ith the glucose content in the tracheobronchial aspirates (r = 0.12; P =.36). Glucose concentrations in 22 enteral formulas determined by 2 methods correlated highly (r = 0.95; P <.001). Glucose concentrations were higher with the laboratory assay (259.6 +/- 206.3 mg/dL) than wit h glucose oxidase reagent strips (188.6 +/- 157.5 mg/dL). CONCLUSION: It appears appropriate to use glucose oxidase reagent strips to estima te glucose concentrations in tracheobronchial fluid. Elevated blood gl ucose levels apparently do not have a major effect on the glucose cont ent in tracheobronchial fluid. Although mean glucose concentrations in the 22 formulas were higher with the laboratory assay, the readings w ere sufficiently similar to allow using glucose oxidase reagent strips to give a good estimation of the formulas' glucose content.