A Service Evaluation of the Appropriateness of Nil by Mouth Decisions in an Acute Hospital Trust

RATIONALE: Use of a 'nil by mouth' (NBM) recommendation is common for patients undergoing general anaesthesia, or where there are concerns around the risk of aspiration or patency of the digestive tract. However, inappropriate use of a NBM recommendation can increase the risk of malnutrition and dehydration. AIMS AND OBJECTIVES: To explore how, why and when NBM decisions are made, and to identify factors associated with the appropriateness of these decisions. METHODS: A retrospective service evaluation was performed in a large acute hospital trust in the UK. All periods of NBM in adult inpatients that commenced in January and February 2022 were identified and reviewed to classify the appropriateness of the clinical decision to commence NBM, and of the duration of NBM. Results were disseminated to clinicians to identify potential explanations for the findings and to surface potential solutions. RESULTS: Of N = 1273 periods of NBM, the majority were due to pre-operative (46.5%) or pre-procedural (32.4%) fasting; most commenced in the early morning (53.9% between 0:00-7:59). The decision to commence NBM was deemed clinically inappropriate in 2.8% of cases, with this being significantly more likely where NBM commenced during the weekend (5.6% vs. 1.8%, p = 0.003) or in the evening (6.3% vs. 1.1% for 17:00-23:59 vs. 0:00-7:59, p = 0.001), in comparison to core weekday working hours. The median duration of NBM was 12.9 h (interquartile range: 7.5-20.3), with this duration being inappropriate in 21.4% of cases. On presenting these findings, clinicians identified unclear communication and documentation of NBM requirements to be major contributors to the inappropriate use of NBM. CONCLUSION: Inappropriate use of NBM is uncommon at our institution but is more likely where this is commenced in evenings or weekends. The cessation of NBM was inappropriately delayed in over a fifth of cases, with poor communication and documentation likely to be a major contributor.