Litmus tests for verification of feeding tube location in infants: evaluation of their clinical use

Aims. To examine the clinical use of litmus paper tests for the assessment of aspirates in infants. Background. In connection with establishing a programme for home care of infants with requirement of tube feeding with parents as the infants' carers, the need for a research-based method for verification of feeding tube position was identified by nurses as a complement to other methods. In adult care the litmus paper test is commonly used when visual inspection is not sufficient for assessment of aspirates obtained from feeding tubes. Design. Observational study. Methods and material. Nurses performed litmus tests for verification of feeding tube location in a convenience sample of 60 infants born at a gestational age (GA) of 24 - 42 weeks. Presence/absence and volumes of aspirates were recorded as well as positive/negative litmus test reactions. Analyses on the association between test results and the infants' GA and postmenstrual and postnatal age at the time of the tests were conducted. Results. Data were obtained from 2970 tube feeds. Aspirates were present on 1840 occasions (62%). A higher proportion of infants with absence of aspirates were born at a GA below 32 weeks. A positive reaction occurred in 97% of the tests in volumes between 0.01 and 22 ml. Birth at a GA below 32 weeks and respiratory problems were associated with negative tests. Conclusion. The high ratio of positive litmus reactions at all maturational levels supports the bedside use of analysis of pH in gastric aspirates for verification of feeding tube location. Relevance to clinical practice. Application of pH indicator paper is recommended as a complementary method for assessment of aspirates from feeding tubes.