Is the STOP-BANG Predictive of Worsening OSA in the Early Postop Period in Patients Undergoing TJA?
Condition: Obstructive Sleep Apnea; Total Knee Arthroplasty
MeSH terms: Apnea; Sleep Apnea Syndromes; Sleep Apnea, Obstructive
Study type: Observational

Summary: 
      The goal of this study is to determine if the investigators can use the STOP-BANG score to
      identify those patients at risk for worsening Obstructive Sleep Apnea (OSA) symptoms in the
      early postoperative period after major surgery.

      Hypotheses:

        1. - Postoperative sleep apnea parameters will be worse when compared to baseline in
           patients with higher scores on the STOP-BANG.

        2. - A higher STOP-BANG score will be predictive of worsening sleep apnea parameters in
           patients undergoing Total Knee Arthroscopy (TKA).
    

Detailed description: 
      Obstructive sleep apnea (OSA) is associated with increased morbidity and mortality after
      total knee arthroplasty (TKA). Up to 30% of surgical patients have undiagnosed OSA; however,
      many patients are unable to obtain a sleep study prior to surgery. In recent years the
      STOP-BANG questionnaire (8 yes-no questions; ≥3 high-risk OSA) has become one of the most
      common tools used in the preoperative period to identify patients at high-risk for OSA.
      However, further research is needed to determine if the STOP-BANG is predictive of worsening
      of sleep apnea parameters in patients undergoing TKA.

      The purpose of this prospective observational cohort study is to determine in TKA patients if
      the score on the STOP-BANG (<3, ≥3 to <5, or ≥5) is predictive of worsening sleep apnea
      parameters (AHI, time with SPO2 <90% & 85% [T90 & T85], lowest oxygen saturation [LSAT], &
      number of central apneas) during the first three days after surgery. The investigators
      propose to enroll N = 168 patients undergoing TKA at NMCSD who are receiving multimodal
      anesthesia/analgesia for surgery. Patients will complete a baseline unattended sleep study
      prior to surgery then again for the first three days after surgery. Patients will be
      categorized into three groups based on their STOP-BANG score (<3, ≥3 to <5, or ≥5) and the
      investigators will first compare the groups to identify if there are differences between
      baseline and postoperative sleep apnea parameters based on the STOP-BANG groups (<3, ≥3 to
      <5, or ≥5). If differences are found the investigators will use multiple regression analysis
      to determine if the STOP-BANG scores or categories and/or other covariates (i.e., comorbidity
      index, total morphine equivalents) are predictive of worsening sleep apnea during the first
      three days after surgery.

      Results of this study may help improve patient safety by allowing us to identify which group
      of TKA patients with undiagnosed OSA may require more intensive postoperative monitoring and
      therapy (i.e, ICU admission, need for continuous end-tidal CO2 monitoring, postoperative
      positive airway pressure therapy) or change in the analgesic plan.
    

Observational model: Case-Only
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        The subject population will be N = 168 patients scheduled for primary or revision TKA
        between the ages of 18-90, at Naval Medical Center San Diego.
      
Keywords: STOP-BANG; Obstructive sleep apnea (OSA); total knee arthroplasty (TKA); portable monitoring; sleep medicine; unattended sleep study; postoperative sleep study