Purpose: This descriptive study sought to determine if gastric residual volume (GRV) threshold values used in clinical practice are associated with aspiration. Background: Lack of agreement about specific GRV threshold values interferes with the delivery of enteral feedings. Fewer than the prescribed number of calories is often delivered because of a fear that high gastric residual volumes will cause aspiration. Sample: A total of 2,643 GRV measurements were made in 185 critically ill adult patients receiving continuous gastric feedings. Eighty-two were fed through 14-18 Fr sump tubes and 103 were fed through 10 Fr polyurethane tubes. Method: GRV measurements were made five times each day for up to three days. Tracheal secretions were assayed for pepsin; if present, the patient was said to have aspirated gastric contents. Patients were categorized as having low GRVs (consistently <100 ml) or high GRVs (defined as two or more ≥100 ml, ≥150 ml or ≥200 ml). Comparisons were made between the percent of pepsin-positive tracheal secretions (PPTS) in patients in the low GRV group and those in the higher GRV groups. Differences were assessed by the Mann-Whitney U test and the independent t-test. Results: Patients in the low GRV group (n=98) had a relatively high percent of PPTS (33.6≠2.5). However, the 20 patients who had two or more GRVs ≥200 ml had a significantly greater percent of PPTS (49.3≠5.2, p = .01). The 37 patients with two or more GRVs ≥150 ml also had a higher percent of PPTS (40.6≠4.2); however, the difference was not statistically significant (p=.07). Over two-thirds of the high GRVs were identified by large-diameter sump tubes. Conclusions: Low GRVs did not prevent aspiration. However, the incidence of aspiration was significantly increased when two or more GRVs ≥200 ml were observed. Funded by NINR, R01 NR0 5007
Session #1349 - Acute Care
The 30th Annual MNRS Research Conference