The SNORE-trial: Analysis of Alterations in Sleep Stages Following Anesthesia and Their Relation to the Severity of Obstructive Sleep Apnea in the First 3 Nights After Surgery

The study is a prospective, observational, single center cohort study on electively scheduled adult surgical patients at the Amsterdam UMC, Amsterdam, The Netherlands.

Patients eligible for inclusion will be identified at the pre-operative screening at the outpatient clinic and contacted and included prior to the day of surgery.

Patients will sign an informed consent. Alternatively patients will be identified by an electronic algoritm which will analyse the next weeks elective surgery list. the algorithm analyzes for sleap apnea; in the patient problem list in their electronic patient file. Patients that have not been identified at the outpatient clinic will be able to be identified as eligible for inclusion via this route.

Measurement will start post-operatively at the recovery ward. All data will be registered with a non-invasive device, the WatchPAT (ZOLL medical). This device will measure apneic and hypopneic incidents, reported as apneu-hypopneu index (AHI) and vital signs such as blood pressure, heart rate and oxygen saturation. In addition the Watchpat will register REM-sleep via actigrapy. Other patient characteristics and demographics will be retrieved from the electronic patient file (EPIC).

These measurements will be started within 30 minutes of arriving at the recovery on the day of surgery continuing on into the first night at the PACU unit. On night 2 and 3 post-operatively participants will be asked to wear the device on the ward when going to sleep for the night. measurement period at the ward will be 8-10 hours.

For results on our primary outcome:

difference in mean of AHI and desaturations on night one compared to night three.

We aimed to detect a difference in mean of an AHI of 0.8 in a design with 3 repeated measurements when assuming a standard deviation of 2 and a very conservative between level correlation of 0. In order to detect a similar difference with a power of 80% and a significance level of 0.05, assuming a drop-out rate of 5%, we will need a sample size of 35 patients.

When patients are lost to follow up, or have incomplete measurements, defined as no functional data on sleep, AHI and desaturations in night 1 or night 3. Where a sleep time of 1,5 hours a night is minimally needed for complete calculations on AHI.

We will use descriptive statistics to present the characteristics of patients, using mean with standard deviation, or median with interquartile range for continuous data and as absolute frequencies with proportions for categorical data. The main outcome measure will be compared using a paired t-test. Correlations will be calculated using Pearsons correlation coefficient.

Inclusion criteria

• Patients scheduled for elective surgery at the operating theatres of the AUMC with a diagnosis of OSA with or without treatment with an expected admittance of a minimum of 3 days
• Patients with continuous positive airway pressure (CPAP) or mandibular advancement device (MAD) are considered patients with treatment for OSA
• Patients ≥ 18 years
• Dutch or English speaking
• Willing and able to sign consent for re-use of care data

Exclusion criteria

• Patients < 18 years
• Not speaking Dutch or English
• Patients who do not sign consent for re-use of care data
• Surgery scheduled in day case or with an expected discharge before the third night after surgery