Do pre-operative blood tests predict patient length of stay in elective total hip replacement?

Abstract

Background: Enhanced recovery begins before the onset of surgery with a thorough pre-operative assessment prior to their procedure. Numerous benefits have been proven from its implementation. Reducing postoperative complications, saving costs, shortening length of stay (LOS), improving patient satisfaction, and promoting faster recovery, are to name a few. Part of the pre-operative assessment includes blood investigations. This study aims to determine whether preoperative blood tests, normal or abnormal, have an effect on a patient’s post-operative length of stay. Objectives: To determine whether pre-operative blood tests, namely haemoglobin (Hb) levels, white cell count (WCC) and renal function tests (with a focus on the estimated glomerular filtration rate (eGFR)), have an effect on patient’s total length of stay in hospital. Study design & methods: A retrospective analysis of pre-operative blood tests, Hb levels, WCC and the eGFR, compared to the total length of stay in hospital, post elective total hip replacement (THR). Over a 9-month period (from January to September 2017), we analyzed 51 patient records who underwent elective total hip arthroplasty within our unit.3 variables were looked at, and these included: Hb levels during admission (prior to surgery), WCC during admission and renal function during admission. Each were compared to the patient’s length of stay. Confounding factors were removed from the study, which largely consisted of the social issues delaying a patient’s discharge. Our data takes into account patients who received a blood transfusion, patients who required antibiotics for a post-operative infection and those patients who required Intensive care (ITU) or High Dependency Unit (HDU) level care. Results: A total of 51 patients were identified, who underwent total hip replacement during this time period. Our data concluded that of these 51 patients, 21 (41%) were found to have a pre-operative Hb below 109g/L and of them 13 (61%) were subsequently discharged later than scheduled (beyond 7 days). Five of these 13 patients (38%) required a postoperative blood transfusion. Of the remaining 30 patients who had a pre-operative Hb greater than 109 g/L, 22 (73%) were discharged early (within 4 days), the remaining 8 patients (26%) were discharged from hospital within 1 week. We also found that of the 51 patients, 17 (33%) patients had a raised pre-operative WCC, of these 17, 9 (53%) were discharged more than 7 days after their surgery. From these 17 patients who had a raised pre-operative WCC and were discharged late, 5 (29%) were treated for a post-operative urinary tract infection (UTI), and 3 patients (18%) were treated for a hospital acquired pneumonia. Of the 51 patients; only 18 (35%) had an eGFR >90, 20 patients (39%) had an eGFR between 60-90, and 13 patients (25%) had an eGFR <60. Of those patients with an eGFR < 60, 10 were discharged more than 4 days after their surgery. Six of these 10 patients (60%) were discharged more than 7 days post-surgery. Conclusion: From the data collected, it is apparent that preoperative investigations prior to and during admission do have an almost predictable effect on the length of stay, and improving these variables would improve the post-operative outcome for our patients. It is imperative that these pre-operative investigations are rigorously analysed prior to the patient being listed for surgery.