Increased Stop Bang Score does not predict increased perioperative risk in patients with sleep apnea undergoing total knee arthroplasty.

INTRODUCTION

In patients undergoing total knee arthroplasty (TKA) obstructive sleep apnea (OSA) is common. Our retrospective study aimed to investigate whether perioperative outcome differ between patients with low-moderate OSA risk and patients with high OSA risk and whether the perioperative outcomes of patients with and without CPAP (continuous positive airway pressure) device differ.

MATERIALS AND METHODS

After excluding patients (missing STOP-Bang-Score, concomitant lung disease) 1444 TKA operated between 2016 and 2020 were included. The STOP-Bang Score was used to determine the risk for OSA (low-moderate risk: Score 0-4, high risk: Score 5-8). SpO2 drops < 90% and readmission rates were compared for low-moderate risk patients and high risk patients as well as for patients with and without CPAP.

RESULTS

There was no difference in SpO2-drops < 90% (1% vs. 1% P = 0.612) and readmission rate (4% vs. 3%, P = 0.537) between low-moderate risk (409 TKA) and high risk patients (1035 TKA). A significant reduction in O2 Flow-Rate (P < 0.001) and no difference in SpO2 (P > 0.999) was observed from post anesthesia care unit to the morning of postoperative day one for both groups. 47% (677/1444) utilized a CPAP machine. There was no difference in the incidence of SpO2 drops < 90% (1% vs. 1%, P = 0.605) and readmission rate (3% vs. 5%, P = 0.055) between both groups.

CONCLUSION

In the absence of underlying pulmonary disease perioperative outcomes did not differ between TKA patients with a low- moderate OSA risk and patients with a high OSA risk according to the STOP Bang Score regardless of the use of a CPAP machine. Outpatient TKA might be an option for optimized OSA patients (without underlying pulmonary disease) regardless of STOP Bang Score and use of a CPAP machine.