110 - Development of postoperative renal dysfunction and anaemia following an elective total knee replacement

Published Date: 19th December 2017

Publication Authors: Murray D, Fletcher J, Yoxall PF

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The guidelines for the provision of anaesthesia services state that patients undergoing major joint replacement are often elderly, with co-existing medical conditions [1]. Peri-operative acute kidney injury is a leading cause of morbidity and mortality [2]. 

Methods 

We conducted retrospective data collection of 194 patients who underwent an elective primary total knee replacement over a 6-month period in 2015. We collected data including anaesthetic technique (general anaesthesia/ spinal/combined), comorbidities (particularly focusing on the presence of diabetes, hypertension, chronic kidney disease and ischaemic heart disease), use of pre-operative/intra-operative NSAIDs, pre- and postoperative urea, creatinine and eGFR. We also looked at pre- and post-operative haemoglobin, use of tranexamic acid and requirement for postoperative blood transfusion. Each patient's length of stay was also recorded. Our primary outcome was to look at the incidence of postoperative renal dysfunction, with a secondary outcome looking at postoperative anaemia and the use of tranexamic acid. The results were subjected to statistical analysis using a paired t-test. 

Results 

The average age of our patients was 68. Spinal anaesthesia was the most commonly conducted form of anaesthesia (168 patients). The most prevalent comorbidity was hypertension which was present in 121 patients. There was no significant increase in postoperative renal dysfunction (urea, creatinine or eGFR) and there appeared to be no association between anaesthetic technique, comorbidity or use of intra-operative NSAIDs and the presence of postoperative renal dysfunction. Forty-one patients received intraoperative tranexamic acid. There was a statistically significant reduction in postoperative anaemia in those patients who received tranexamic acid intra-operatively (standard error 1.06, 95% confidence interval upper bound 31.2, lower bound 26.9, p = 0.02). 

Discussion 

We found no significant difference between the anaesthetic techniques/ drugs administered and the development of postoperative renal dysfunction. However, our study was likely to be underpowered to detect such a difference. Our results are supported by a meta-analysis [3] involving more than 10,000 patients undergoing a range of procedures which confirmed that tranexamic acid use is associated with a 37% reduction in blood transfusion.

Murray, D; Fletcher, J; Yoxall, P. (2017). Development of postoperative renal dysfunction and anaemia following an elective total knee replacement. Retrospective data collection examining different anaesthetic techniques in a district general hospital . Anaesthesia. 72 (S3), 65

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