Abstract
Background
Patients who undergo elective hip and knee arthroplasty often have multiple risk factors increasing their likelihood of suffering from hyponatraemia post operatively. Consequently suffering from hyponatraemia post elective hip and knee arthroplasty is common. Consequently we wanted to assess the occurrence of hyponatraemia in our elective arthroplasty unit, assess our effectiveness in managing this and importantly assess how its occurrence impacted on length of patient stay.
Method
Retrospective analysis of elective hip and knee arthroplasty patients over a five month period. Pre-operative and post-operative sodium levels analysed and their grade measured using NICE reference ranges. In post-operative hyponatraemic patients blood results were analysed up until discharge. Discharge summaries were reviewed to assess communication between primary and secondary care. Length of admission calculated. Formal action plan developed in partnership with the anaesthetic department to improve future management.
Results
103 patients assessed. 24 (23%) suffered from post-operative hyponatraemia. 11 (48%) were discharged with a normalised sodium. 7 (29%) had documentation regarding their hyponatraemia in the discharge summary. 101 (98%) had a sodium drop post-operatively and 2 patients were hyponatraemic pre-operatively. Average length of stay for hyponatraemic hip patients was 5.00 days compared to 4.20 days for patients with normal sodium levels. Hyponatraemic post op knee patients had an average in hospital stay of 5.09 days compared to 4.13 days in knee patients with a normal post-operative sodium level.
Conclusion
Hyponatraemia is common in the post-operative arthroplasty patient. In our unit it led to an increase in length of hospital stay. We believe the introduction of a structured post-operative oral rehydration regime with isotonic fluid would be a simple method to reduce occurrence post operatively. We feel standardising intra-operative fluid prescribing will reduce the likelihood of pushing patients into a post-operative hyponatraemic state. Finally we have introduced a hyponatraemia management flowchart to the department so ward based doctors can recognise and effectively manage hyponatraemic patients. If these measures are implemented length of stay in hospital can potentially be reduced.
