Trial Review

Did you know?

The ANZCTR now automatically displays published trial results and simplifies the addition of trial documents such as unpublished protocols and statistical analysis plans.

These enhancements will offer a more comprehensive view of trials, regardless of whether their results are positive, negative, or inconclusive.

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been endorsed by the ANZCTR. Before participating in a study, talk to your health care provider and refer to this information for consumers
Trial registered on ANZCTR


Registration number
ACTRN12617000199314
Ethics application status
Approved
Date submitted
30/01/2017
Date registered
6/02/2017
Date last updated
29/01/2018
Type of registration
Prospectively registered

Titles & IDs
Public title
Assessment and management of obstructive sleep apnoea following bariatric surgery
Scientific title
Assessment and management of obstructive sleep apnoea following bariatric surgery
Secondary ID [1] 291013 0
None
Universal Trial Number (UTN)
U1111-1192-1009
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Obstructive sleep apnoea 301789 0
Obesity 301790 0
Condition category
Condition code
Respiratory 301482 301482 0 0
Sleep apnoea
Surgery 301510 301510 0 0
Other surgery
Diet and Nutrition 301553 301553 0 0
Obesity

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Auto-titrated continuous positive airway pressure (APAP)

Continuous positive airway pressure (CPAP) is a machine that blows air through a mask while a patient is sleeping. The pressure of the air keeps the airway open and makes breathing easier during sleep. Continuous positive airway pressure (CPAP) is the treatment of choice for OSA in the general population as it improves snoring, sleep quality, daytime sleepiness and fatigue. However, it is unclear whether CPAP reduces the risk of complications following weight loss surgery in people with OSA. Initially there were concerns that pressurised air would inflate the stomach and intestine following bariatric surgery but CPAP has not been shown to increase the risk of anastomotic disruption.

Auto-titrated CPAP (APAP) is a type of CPAP. Flow is measured with every breath and the delivered pressure is adjusted to maintain an unobstructed airway. One advantage of using APAP, in the postoperative period, is that treatment can be started without prior CPAP titration. The time interval between a patient’s appointment at the anaesthetic preassessment clinic and their operation is usually very short. In most hospitals, it would be impossible to both diagnose OSA with polysomnography and optimise the patient’s CPAP setting in this short space of time. Furthermore, the preoperative CPAP setting may be insufficient in the immediate postoperative phase due to the administered perioperative sedatives and analgesics.

APAP group will receive
1. Postopeartive APAP treatment on the night of surgery;
2. Continuous postoperative blood oxygen level/saturation (SpO2) monitoring on the night of surgery, i.e. routine practice; and
3. Supplemental oxygen if SpO2 is <90%, i.e. routine practice.
Intervention code [1] 296984 0
Diagnosis / Prognosis
Intervention code [2] 296985 0
Treatment: Devices
Comparator / control treatment
Control group will receive
1. Postoperative ApneaLink monitoring on the night of surgery to monitor AHI;
2. Continuous postoperative blood oxygen level/saturation (SpO2) monitoring on the night of surgery, i.e. routine practice; and
3. Supplemental oxygen if SpO2 is <90%, i.e. routine practice.

Level 1 sleep testing or polysomnography is the “gold standard” tool for diagnosing OSA. However, it is inconvenient for the patient as it requires an overnight stay in a sleep laboratory. In addition, it is labour-intensive, costly and has limited availability. These drawbacks make it impractical to use polysomnography routinely to diagnose OSA preoperatively. In contrast, level 3 portable devices (e.g. ApneaLink) can be used at home and are less expensive. A systematic review has shown that these portable devices are very useful to diagnose OSA in patients with a high pretest probability of having moderate or severe OSA. ApneaLink has both a high sensitivity (90.9%) and specificity (94.6%) at an apnoea-hypopnoea index (AHI) >15 events per hour, i.e. patients with at least moderate OSA.

ApneaLink is a monitoring device only, i.e. there is no intervention delivered. The device consists of a nasal cannula that attaches to a small pressure transducer. This records nasal flow and therefore apnoeas and hypopnoeas.. The pressure transducer sits in a small case which is attached to a chest strap that records respiratory effort.
Control group
Active

Outcomes
Primary outcome [1] 300890 0
Incidence of undiagnosed OSA in the bariatric surgical population.

Patients will complete a STOP-BANG questionnaire (attached to ANZCTR registration form) which will assess their risk of OSA. The STOP-BANG questionnaire is easy to perform and is the most validated screening tool for OSA in surgical patients. A STOP-BANG score >3 has a high sensitivity for detecting moderate (93%) and severe (100%) OSA.

Patients will also perform a home sleep test (ApneaLink). ApneaLink has both a high sensitivity (90.9%) and specificity (94.6%) at an apnoea-hypopnoea index (AHI) >15 events per hour, i.e. patients with at least moderate OSA.
Timepoint [1] 300890 0
Preoperatively. The STOP-BANG questionnaire will be performed at the anaesthetic preassessment clinic which is usually 1 month prior to the operation. The ApneaLink home sleep study will be performed over one of the nights, in the time between the anaesthetic preassessment clinic and the operation.
Primary outcome [2] 300891 0
Difference in postoperative AHI, in patients undergoing laparoscopic bariatric surgery with moderate or severe OSA, using APAP compared with routine practice.

The AHI is recorded by the APAP machine (APAP group) and the ApneaLink (Control group).
Timepoint [2] 300891 0
The night of the operation.
Secondary outcome [1] 331130 0
Difference in postoperative oxygen saturations (SpO2), in patients undergoing laparoscopic bariatric surgery with moderate or severe OSA, using APAP compared with routine practice.

Pulse oximeter will be placed on the patient's finger overnight to record continuous oxygen saturations. These readings will be downloaded onto an investigator's computer for review.
Timepoint [1] 331130 0
The night of the operation.
Secondary outcome [2] 331131 0
Difference in postoperative adverse events, in patients undergoing laparoscopic bariatric surgery with moderate or severe OSA, using APAP compared with routine practice.

Patient's notes will be reviewed following discharge looking for adverse events that occurred during their hospital admission. Examples of adverse events are: mortality, unplanned admission to critical care, nausea, vomiting and dry airways.
Timepoint [2] 331131 0
During the hospital admission which is usually 2-3 days.
Secondary outcome [3] 331181 0
Difference in supplemental oxygen required, in patients undergoing laparoscopic bariatric surgery with moderate or severe OSA, using APAP compared with routine practice.

Patient's notes (specifically the observation chart) will be reviewed for the nurse's documentation of the supplemental oxygen administered.
Timepoint [3] 331181 0
The night of the operation.

Eligibility
Key inclusion criteria
Patients undergoing laparoscopic bariatric surgery at Joondalup Health Campus, Western Australia:
1. Without a formal diagnosis of OSA, or
2. With a formal diagnosis of OSA but not using CPAP therapy.
Minimum age
18 Years
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Patients with a formal diagnosis of OSA and using CPAP therapy.
Patients undergoing other types of bariatric surgery, e.g. open surgery, gastric band removal.
Patient refusal.

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Sealed opaque envelopes
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Computerised sequence generation
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Safety/efficacy
Statistical methods / analysis
Power analysis will need to be performed once results from the trial are analysed. We require the incidence of undiagnosed OSA prior to performing an power analysis.

Joondalup Health Campus performs around 400 laparoscopic bariatric surgical procedures per year.

Descriptive statistics will be performed on demographic data.

Continuous data with a normal distribution will be presented as a mean + standard deviation. The T test will be used to compare groups.

Data with a skewed distribution will be presented as a median and interquartile range. The Mann-Whitney U test will be used to compare groups.

Categorical data will be presented as frequency and percentage. The Chi-square test will be used to compare groups.

A P value <0.05 will be considered statistically significant.

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
1/03/2017
Actual
13/04/2017
Date of last participant enrolment
Anticipated
28/02/2019
Actual
Date of last data collection
Anticipated
30/04/2019
Actual
Sample size
Target
200
Accrual to date
190
Final
Recruitment in Australia
Recruitment state(s)
WA
Recruitment hospital [1] 7396 0
Joondalup Health Campus - Joondalup
Recruitment postcode(s) [1] 15193 0
6027 - Joondalup

Funding & Sponsors
Funding source category [1] 295441 0
Hospital
Name [1] 295441 0
Joondalup Health Campus
Country [1] 295441 0
Australia
Primary sponsor type
Individual
Name
Christopher Wong
Address
Department of Anaesthesia
Joondalup Health Campus
Shenton Ave
Joondalup
WA 6027
Country
Australia
Secondary sponsor category [1] 294260 0
None
Name [1] 294260 0
Address [1] 294260 0
Country [1] 294260 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 296772 0
Joondalup Health Campus Human Research Ethics Committee
Ethics committee address [1] 296772 0
Joondalup Health Campus
Shenton Ave
Joondalup
WA 6027
Ethics committee country [1] 296772 0
Australia
Date submitted for ethics approval [1] 296772 0
25/01/2017
Approval date [1] 296772 0
13/03/2017
Ethics approval number [1] 296772 0
1703

Summary
Brief summary
Obstructive sleep apnoea (OSA) is a sleep disorder where patients stop breathing or have extremely shallow breathing during sleep. Excess weight increases the risk of OSA. However, the majority of patients with OSA that present for weight loss surgery are unaware that they have OSA.

The first aim of this study is to see how common it is for patients to present for weight loss surgery with undiagnosed OSA. Before their operation, patients will answer a questionnaire (STOP-BANG) and will undergo a home sleep test (ApneaLink).

Continuous positive airway pressure (CPAP) is the preferred everyday treatment for OSA. However, it is unknown whether the application of CPAP prevents complications, following weight loss surgery.

The other aims of this study are to see if auto-titrated CPAP (APAP), following weight loss surgery:
1. Decreases the number of times a patient stops breathing or has extremely shallow breathing during sleep;
2. Improves oxygen levels in the blood; and
3. Prevents complications.

Following their operation, patients with moderate or severe OSA (diagnosed from their ApneaLink home sleep testing) will be randomised to either:
1. Control group
a. Overnight ApneaLink monitoring
b. Oxygen and OSA monitoring
c. Additional oxygen if required
2. APAP group
a. Overnight APAP
b. Oxygen and OSA monitoring
c. Additional oxygen if required

The number of times per hour that a patient stops breathing or has extremely shallow breathing during sleep (i.e. AHI) will be compared between the control and APAP groups. The two groups will also be compared regarding their blood oxygen levels (SpO2), additional oxygen requirement and complications, such as unplanned admissions to critical care.
Trial website
Trial related presentations / publications
Public notes
Attachments [1] 1404 1404 0 0
/AnzctrAttachments/372238-OSA Bariatric - Participant information form and consent.pdf (Participant information/consent)
Attachments [2] 1405 1405 0 0
/AnzctrAttachments/372238-OSA Bariatric - STOP-BANG Questionnaire.pdf (Other)

Contacts
Principal investigator
Name 72010 0
Dr Christopher Wong
Address 72010 0
Department of Anaesthesia
Joondalup Health Campus
Shenton Ave
Joondalup
WA 6027
Country 72010 0
Australia
Phone 72010 0
+64211716609
Fax 72010 0
Email 72010 0
[email protected]
Contact person for public queries
Name 72011 0
Christopher Wong
Address 72011 0
Department of Anaesthesia
Joondalup Health Campus
Shenton Ave
Joondalup
WA 6027
Country 72011 0
Australia
Phone 72011 0
+64211716609
Fax 72011 0
Email 72011 0
[email protected]
Contact person for scientific queries
Name 72012 0
Christopher Wong
Address 72012 0
Department of Anaesthesia
Joondalup Health Campus
Shenton Ave
Joondalup
WA 6027
Country 72012 0
Australia
Phone 72012 0
+64211716609
Fax 72012 0
Email 72012 0
[email protected]

No information has been provided regarding IPD availability


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.