Assessment of fecal output in patients receiving enteral tube feeding: validation of a novel chart

Objective: To develop a practical, valid and reliable chart to assist in the accurate visual characterization of fecal output in patients receiving enteral tube feeding (ETF). Design: A chart incorporating verbal and pictorial descriptors of fecal output was developed. Validity and reliability were assessed by a questionnaire survey of health professionals and a clinical study of patients commencing ETF. Content validity was assessed from the results of the questionnaire, construct validity by contrasting groups analysis, concurrent validity by comparison of the chart with actual fecal weight and inter-rater reliability by independent characterization of the same fecal sample by two nurses. Setting: St George's Hospital, London, UK. Subjects: In all, 35 health professionals completed a questionnaire with respect to the chart. The chart was then used to monitor fecal output in 36 patients commencing ETF for a total of 171 patient-days, during which time nurses used the chart to characterize 269 fecal samples, of which 59 were subsequently weighed. Results: The results of the questionnaire suggested good content validity. The chart demonstrated statistically significant differences in fecal frequency, fecal consistency, fecal score and incidence of diarrhea for contrasting patient groups expected to have different fecal output (P<0.05). The inter-rater reliability was almost perfect for fecal consistency (95% agreement, kappa = 0.91) and substantial for fecal weight (83%, kappa = 0.75). In all, 83% of fecal samples were assigned to the correct weight category (kappa = 0.75). Conclusion: The chart has good content, construct and concurrent validity and inter-rater reliability, and is suitable for both research and clinical use.