Brain natriuretic peptide and impedance cardiography to assess volume status in peritoneal dialysis patients.

Assessment of volume status in patients with end-stage renal disease has long been a problem. Objective tools for estimating dry weight are necessary. The present study was designed to determine if better assessment of volume status could be achieved by measuring brain natriuretic peptide (BNP) and thoracic fluid content (TFC) by bioimpedance. We prospectively surveyed 51 medically stable peritoneal dialysis (PD) patients during their routine visits to our PD facility. There were no exclusion criteria. Clinical volume status was assessed by the attending nephrologist as hypovolemic, euvolemic, or hypervolemic. Once the clinical assessment was complete, plasma BNP concentration was measured. The TFC was determined by bioimpedance cardiography measured in the supine position. Of 51 patients, 19 (37.3%) were considered hypervolemic, 30 (58.8%) euvolemic, and 3 (5.9%) hypovolemic by clinical assessment. As defined by systolic blood pressure > or = 130 mmHg or diastolic pressure > or = 80 mmHg (or both), 57% were hypertensive. The hypovolemic group was excluded from the statistical analysis because of the small sample size. Logistic regression analysis did not show a significant correlation between clinical assessment of volume and BNP (p = 0.76) or TFC (p = 0.39). Our data demonstrate the limitations of BNP and thoracic impedance in helping with the clinical evaluation of volume status in a cohort of chronic PD patients.

Usefulness and validity of diagnostic nasogastric aspiration in patients without hematemesis.

STUDY OBJECTIVE: We estimate the test characteristics of nasogastric aspiration to diagnose upper gastrointestinal tract hemorrhage in patients without hematemesis. METHODS: In this retrospective cohort study, medical records from patients admitted to 2 urban hospitals between 1997 and 2002 for gastrointestinal tract bleeding without hematemesis were reviewed. Positive nasogastric aspiration results were classified by the severity of hemorrhage, and negative results were classified by the presence or absence of bile. The reference standard for nasogastric aspiration was the source of bleeding-upper versus non--upper gastrointestinal tract--from the hospital discharge summary. Confidence intervals (CIs) for proportions and likelihood ratios (LRs) were calculated. RESULTS: Of 333 eligible patients, 235 were offered nasogastric aspiration, and 220 accepted the test. Results of 220 attempts were distributed as follows: negative, 158 (72%), including 9 (4%) with bile; nasogastric aspiration aborted, 13 (6%); and positive, 49 (23%), including 4 (2%) that were strongly positive (> or =450 mL red blood). Test characteristics of nasogastric aspiration to detect upper gastrointestinal tract bleeding in 213 patients with a reference standard diagnosis were as follows: sensitivity 42% (95% CI 32% to 51%), specificity 91% (95% CI 83% to 95%), negative predictive value 64% (95% CI 56% to 71%), and positive predictive value 92% (95% CI 79% to 97%). The nasogastric aspiration accurately predicted the source of bleeding in 66% of patients (95% CI 59% to 72%). The likelihood ratio of a positive nasogastric aspiration was 11 (95% CI 4 to 30), and the likelihood ratio of a negative nasogastric aspiration was 0.6 (95% CI 0.5 to 0.7). CONCLUSION: In patients without hematemesis, a positive nasogastric aspiration, seen in 23%, indicates probable upper gastrointestinal tract bleeding (LR+ 11), but a negative nasogastric aspiration, seen in 72%, provides little information (LR- 0.6).

ED predictors of upper gastrointestinal tract bleeding in patients without hematemesis.

OBJECTIVES: In patients with gastrointestinal (GI) tract bleeding, the bleeding source is uncertain in the absence of hematemesis. We sought to identify clinical variables predictive of an upper GI bleeding source. METHODS: This retrospective cohort study involved patients admitted via the ED for GI tract bleeding without hematemesis, who underwent confirmatory testing. We used logistic regression analysis to identify clinical variables independently associated with an upper GI source. RESULTS: Among 325 patients, odds ratios for the strongest predictors were as follows: black stool, 16.6 (95% confidence interval [CI], 7.7-35.7); age less than 50 years, 8.4 (95% CI, 3.2-22.1); and blood urea nitrogen/creatinine ratio 30 or greater, 10.0 (95% CI, 4.0-25.6). Seven (5%) of 151 with none of these factors had an upper GI tract bleed, versus 63 (93%) of 68 with 2 or 3 factors. CONCLUSION: Black stool, age less than 50 years, and blood urea nitrogen/creatinine ratio of 30 or greater independently predict an upper GI tract bleeding source.