What’s New in the Patient Safety World

April 2019

New Simple OSA Screening Tool: BOSTN



We’ve done numerous columns on obstructive sleep apnea (OSA) and particularly the risks OSA brings in the perioperative period. Therefore, we always advocate screening patients for OSA preoperatively. Though there are several tools that can be used for screening, the STOP-Bang tool is the one used most often and has been well validated.


But now a new simpler tool, the BOSTN score, has generated considerable interest (Raub 2018). The BOSTN score assigns one point for each of the following:

·       Body mass index of 30 kg/m2 or greater

·       Observed apnea

·       Snoring that is loud

·       Tiredness in the daytime

·       Neck circumference of 16.5 inches or greater in females and 17.5 inches or greater in males


 A score of 2 or more points indicates a high risk for OSA.


Raub and colleagues reported on their experience with use of BOSTN at Beth Israel Deaconess Medical Center (BIDMC).  BOSTN is preoperatively applied by nurses at BIDMC. Patients with high OSA risk are then flagged in the medical record, and electronic decision support options are provided to clinicians.


Over 200,000 adult patients undergoing non-cardiac surgery between 2008-2017 were evaluated. Patients with an ASA classification of 6 or undergoing multiple surgical procedures in one day were excluded. 9.6% of these were classified as high risk for OSA by BOSTN score and 1.5% of these required postoperative mechanical ventilation within 7 days after surgery.

Patients with BOSTN ≥ 2 and STOP-BANG ≥ 5 showed lower odds for postoperative mechanical ventilation (aOR 0.58). Patients with BOSTN ≥ 2 were discharged earlier (aIRR 0.65) and were less frequently readmitted within 30 days (aOR 0.91).


C-statistics revealed an excellent diagnostic ability of both BOSTN and STOP-BANG for postoperative mechanical ventilation requirement and the predictive performance of the two tools was comparable.


The authors conclude that clinical implementation of the BOSTN screening, paired with a decision support system in the electronic medical record, a flag of BOSTN ≥ 2 is associated with improved respiratory complication rates and decreased hospital utilization rates.


We consider preoperative screening for OSA one the most important pieces of a good pre-op evaluation (see our August 17, 2010 Patient Safety Tip of the Week “Preoperative Consultation – Time to Change”). The STOP-Bang score is still the gold standard but we expect to see a lot more using the BOSTN score.



Our prior columns on obstructive sleep apnea in the perioperative period and other acute settings:


June 10, 2008              “Monitoring the Postoperative COPD Patient”

August 18, 2009         “Obstructive Sleep Apnea in the Perioperative Period”

August 17, 2010         “Preoperative Consultation – Time to Change”

July 2010                    “Obstructive Sleep Apnea in the General Inpatient Population”

July 13, 2010              “Postoperative Opioid-Induced Respiratory Depression”

November 2010          “More on Preoperative Screening for Obstructive Sleep Apnea”

February 22, 2011       “Rethinking Alarms”

November 22, 2011    “Perioperative Management of Sleep Apnea Disappointing”

March 2012                 “Postoperative Complications with Obstructive Sleep Apnea”

May 22, 2012              “Update on Preoperative Screening for Sleep Apnea”

February 12, 2013       “CDPH: Lessons Learned from PCA Incident”

February 19, 2013       “Practical Postoperative Pain Management”

March 26, 2013           “Failure to Recognize Sleep Apnea Before Surgery”

June 2013                    “Anesthesia Choice for TJR in Sleep Apnea Patients”

September 24, 2013    “Perioperative Use of CPAP in OSA”

May 13, 2014              “Perioperative Sleep Apnea: Human and Financial Impact”

March 3, 2015             “Factors Related to Postoperative Respiratory Depression”

August 18, 2015         “Missing Obstructive Sleep Apnea”

June 7, 2016                “CPAP for Hospitalized Patients at High Risk for OSA”

October 11, 2016        “New Guideline on Preop Screening and Assessment for OSA”

November 21, 2017    “OSA, Oxygen, and Alarm Fatigue”

July 17, 2018              “OSA Screening in Stroke Patients”






Raub D, Nabel S, Rostin P, et al. Validation of the Boston Score, A Clinically Established Preoperative Prediction Instrument to Quantify Obstructive Sleep Apnea. 2018 Annual Meeting of the American Society of Anesthesiologists (abstract A2266).






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