Pre-operative hemoglobin level and use of sedative-hypnotics are independent risk factors for post-operative delirium following total knee arthroplasty

Eiji Kijima,Mitsuru Saito,Daisaburo Kurosaka,Keishi Marumo,Takashi Hyakutake,Ryo Ikeda,Daisuke Kubota,Tomohiro Kayama,Hiroteru Hayashi

doi:10.1186/s12891-020-03206-4

Eiji Kijima, Mitsuru Saito + Show 7 more

Open Access

https://doi.org/10.1186/s12891-020-03206-4

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Abstract

BackgroundDelirium is a well-known complication following surgery, especially with the increasing age of patients undergoing surgery. The increasing demands resulting from a prolonged healthy life expectancy has resulted in more arthroplasties despite their age and existing comorbidities. The purpose of this study is to explore the various risk factors that may contribute to delirium in unilateral and bilateral total knee arthroplasties in the elderly population.Methods170 patients who underwent unilateral or bilateral total knee arthroplasties were analyzed retrospectively for delirium. Age, sex, comorbidities, use of sedative-hypnotics, peri-operative blood loss, pre- and post-operative laboratory blood test results were investigated and analyzed.ResultsThe incidence of post-operative delirium was 6.5% (11 out of 170 patients) with a mean age of 79.5 (± 6.9) years, compared to 73.0 (± 9.0) years in the non-delirium group. Higher age, use of sedative-hypnotics, low pre-operative Hb and Ht, low post-operative Hb, Ht and BUN were observed in the delirium group. Multivariate logistic regression analysis identified that the use of sedative-hypnotics and pre-operative Hb level were independent risk factors for post-operative delirium after TKA. The odds ratios for the use of sedative-hypnotics and pre-operative Hb level were 4.6 and 0.53, respectively. Receiver operating characteristic curve analysis showed that pre-operative Hb of less than 11.1 g/dL was a predictor for the development of delirium, with a sensitivity of 54.6% and a specificity of 91.6%.ConclusionPatients with a pre-operative Hb level of < 11.1 g/dL or those using sedative-hypnotics are associated with post-operative delirium. Peri-operative management and preventative measures are therefore needed to reduce the risks of post-operative delirium in such patients.

Highlights

Delirium is a well-known complication following surgery, especially with the increasing age of patients undergoing surgery
In the Asian population who underwent total knee arthroplasty (TKA), history of dementia, history of cerebrovascular disease, low BMI, chronic opioid use, large decrease in post-operative Hb and albumin, and post-operative high Blood urea nitrogen (BUN) have been associated with post-operative delirium [9, 14, 18]
Receiver operating characteristic (ROC) curve analysis showed that preoperative Hb of less than 11.1 g/dL was a predictor for the development of delirium, with a sensitivity of 54.6% and a specificity of 91.6% (AUC value 0.77) (Fig. 1)

Summary

Introduction

Delirium is a well-known complication following surgery, especially with the increasing age of patients undergoing surgery. The purpose of this study is to explore the various risk factors that may contribute to delirium in unilateral and bilateral total knee arthroplasties in the elderly population. Post-operative delirium is a serious condition associated with adverse clinical and economic outcomes, including higher rates of major complications, decreased cognitive function, poor functional recovery, increased length of stay, increased mortality, and higher costs [3,4,5,6]. A systematic review by Bin Abd Razak et al have identified age, history of psychiatric illness, decreased functional status and decreased verbal memory as independent predictors of delirium in total joint arthroplasties. The use of isofluorane for general anaesthesia and benzodiazepines have been implicated while cognitive assessment has been found to be a useful predictor for post-operative delirium [19]

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