Semi-up Right Position Study

Does a Semi-upright Position During Sleep Prevent Worsening of Severity of Obstructive Sleep Apnea (OSA) on the Second Postoperative Night in Patients Following Elective Inpatient Surgery? A Two Arm, Parallel, Randomized, Controlled, First Stage Proof of Concept Trial

Our main objective is to perform an explanatory, first stage proof of concept, randomized controlled trial to determine whether a semi-upright patient position versus a supine position while asleep in the postoperative period helps decrease the worsening of AHI in patients diagnosed with OSA and compare this to usual care (i.e. supine patient positioning while asleep).

The investigators will evaluate whether a semi-upright position reduces: worsening of AHI (as measured with a portable PSG) on the second postoperative night (POD2); oxygen desaturation index (using a portable oxygen saturation monitor, oxygen desaturation defined as >4% change below baseline lasting for 10 seconds); REM sleep related change in AHI at baseline and POD2.; major and minor perioperative complications on postoperative day POD1, POD2, at discharge and POD 30.; length of hospital stay and readmission within 30 days; and patient satisfaction score on POD30

Study Overview

• Status: Completed
• Conditions: Obstructive Sleep Apnea
• Intervention / Treatment: Other: Semi-upright position; Other: Supine position

Detailed Description

The proposed study is to determine whether patient positioning in supine or semi-sitting position can effectively control the worsening of OSA see in the postoperative period.

The study patient will be randomized to semi-sitting position (45 degrees incline) group or supine (0 degrees incline) group. Patients will undergo a portable sleep study on the first or second postoperative night. They will also be monitored with wristwatch oximeter pre and postoperatively according to the study protocol. Patients will be managed according to the routine care determined by the health care team. There will be no change in the clinical management of patients.

• Study Type: Interventional
• Enrollment (Actual): 164
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Canada
  • Ontario
    • Toronto, Ontario, Canada, M5T2S8
      • Toronto Western Hospital, Department of Aneshtesia
    • Toronto, Ontario, Canada, M5G 1X5
      • Mount Sinai Hospital, Department of Anesthesia
    • Toronto, Ontario, Canada, M5T2S8
      • University Health Network, Department of Anesthesia
    • Toronto, Ontario, Canada
      • Toronto Western Hospital, Department of Aneshtesia

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Adult patients (18 years and above),
• ASA physical status I to IV,
• Undergoing elective inpatient surgery with obstructive sleep apnea (as determined by initial screening using STOP-Bang questionnaire and if at high risk (>3 points),
• Confirmed by an Apnea-hypopnea index (AHI) >5 using a diagnostic home portable polysomnography)

Exclusion Criteria:

• Patients previously diagnosed as OSA and on continuous positive airway pressure (CPAP) device;
• Known cervical, shoulder, spine abnormalities, and/or chronic pain predisposing to difficulty in maintaining a sitting position; or
• Previous intervention for OSA (e.g., uvulopalatopharyngoplasty, bariatric surgery); where sitting position is contraindicated postoperatively such as hip or spine surgery, hemodynamic instability; ambulatory surgery i.e. planned discharge on the same day of surgery.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Single Group Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Semi-upright position; Semi-upright position defined as 45 degrees incline from horizontal of the patients bed during nocturnal sleep, for two postoperative nights. Daytime naps will be excluded. A regular pillow may be used by the patients based upon the level of comfort and also to support the head in a neutral position.	Other: Semi-upright position; In this group patients' bed will be set into 45 degree angle during sleep in the night time.; Other Names: Semi-upright position (45 degree bed angle)
Other: Control group (Supine position); In this group patients' bed will be set into Supine/0 degree angle during sleep in the night time. Patient will be managed according to routine care	Other: Supine position; Control: Supine position during nocturnal sleep for at least two postoperative nights.; Other Names: Control group

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Comparison of worsening of severity of OSA using the Apnea-hypopnea index (AHI) as determined by a portable polysomnography study from baseline (preoperatively) to the second postoperative night.	The AHI is used as a surrogate outcome to establish the diagnosis of OSA (AHI>5) and severity of OSA as per the guidelines from American Academy of Sleep Physicians (AASP).5 It is a continuous outcome and is measured by counting the number of apneas (complete cessation of airflow for more than 10 s) and hypopneas (airflow reduction more than 50%) despite continuing breathing efforts and thus differentiating from central events (absence of breathing efforts). The relationship of AHI to clinical outcomes of relevance has been well established in the literature.	3days

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Major and minor perioperative complications and length of hospital stay on postoperative day (POD) 1, POD2, at discharge and POD 30 will be recorded based on chart review.	The oxygen desaturation index; REM sleep related change in AHI at baseline and POD2 and time spent in lateral position while asleep will be deciphered from the PSG data.	30 days
Hospital stay	Length of hospital stay, readmission within 30 days, and patient satisfaction score will be recorded and telephonic interview with the patient on POD30.	30 days

Collaborators and Investigators

• Sponsor: University Health Network, Toronto
• Investigators: Principal Investigator: Frances Chung, MD, University Health Network, Toronto

Publications and helpful links

General Publications

• Lukachan GA, Yadollahi A, Auckley D, Gavrilovic B, Matelski J, Chung F, Singh M. The impact of semi-upright position on severity of sleep disordered breathing in patients with obstructive sleep apnea: a two-arm, prospective, randomized controlled trial. BMC Anesthesiol. 2023 Jul 13;23(1):236. doi: 10.1186/s12871-023-02193-y.

Study record dates

Study Major Dates

• Study Start (Actual): July 1, 2011
• Primary Completion (Actual): December 1, 2016
• Study Completion (Actual): December 1, 2016

Study Registration Dates

• First Submitted: May 22, 2014
• First Submitted That Met QC Criteria: May 28, 2014
• First Posted (Estimated): June 2, 2014

Study Record Updates

• Last Update Posted (Actual): May 4, 2026
• Last Update Submitted That Met QC Criteria: April 28, 2026
• Last Verified: May 1, 2016

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Nervous System Diseases; Respiratory Tract Diseases; Respiration Disorders; Sleep Wake Disorders; Apnea; Sleep Disorders, Intrinsic; Dyssomnias; Sleep Apnea Syndromes; Sleep Apnea, Obstructive; Musculoskeletal Physiological Phenomena; Musculoskeletal and Neural Physiological Phenomena; Investigative Techniques; Epidemiologic Research Design; Epidemiologic Methods; Research Design; Methods; Posture; Control Groups; Supine Position
• Other Study ID Numbers: Protocol version july 17, 2011