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Trial registered on ANZCTR


Registration number
ACTRN12615001037594
Ethics application status
Approved
Date submitted
7/09/2015
Date registered
6/10/2015
Date last updated
14/09/2016
Type of registration
Prospectively registered

Titles & IDs
Public title
Feasibility of performing measurements of airway collapse during tonsillectomy surgery in children.
Scientific title
Is it feasible to perfom (and repeat) airway collabsibility measurements in the paediatric population who are undergoing tonsillectomy procedures and does this data relate to patients having obstructive sleep apnoea and the associated risk of perioperative respiratory adverse events?
Secondary ID [1] 287424 0
OSATS: the Obstructive Sleep Apnoea study: making Tonsillectomies Safer
Universal Trial Number (UTN)
Trial acronym
OSATS
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Respiratory complications under general anaesthetic in children undergoing tonsillectomy (+/-adenoids/grommets) procedures. 296135 0
Condition category
Condition code
Anaesthesiology 296402 296402 0 0
Anaesthetics
Respiratory 296403 296403 0 0
Sleep apnoea
Surgery 296528 296528 0 0
Surgical techniques

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Measuring the propensity of upper airway collapse may provide more accurate physiological data to grade Obstructive Sleep Apnoea (OSA) and consequently narrow down the variability in the estimated probability of perioperative respiratory adverse events.
The study will start by the screening for the presence of obstructive sleep apnoea.
Measurements of airway collapsibility pressure will be carried out at three different perioperative phases;
(1) Just after induction of anaesthesia and prior to insertion of the airway device
(2) At emergence just after the removal of the airway device
(3) In the recovery phase prior to being awake.

Upper airway collapsibility pressure will be measured at the above three timepoints. Each measurement will be between 15 and 30 seconds and repeated twice to give an accurate result. This involves the use of a nasal mask and requires the patient to be breathing spontaneously while anaesthesia is maintained. A pressure transducer will continuously measures pressure changes within the nasal mask. Airflow and phase of respiratory cycle will be monitored either by a pneumotachograph attached to the nasal mask, or by visually monitoring the patient’s chest wall movement.
After ensuring that the nasal mask is leak free by optimising the seal, at end-expiration it will be occluded and the pressure-time profile monitored for evidence of ‘flattening’ - indicating upper airway collapse. (Breathing will be blocked for between 15 to 30 seconds.) The pressure at which this occurs (termed Pclose) will be recorded. Once the flattening of the curve is observed, the nasal mask is removed and breathing returns to normal. Air flow will be monitored for all patients to ensure adherence to the protocol. All results of airway collapsability will be recorded in a study data collection log.
Intervention code [1] 292783 0
Diagnosis / Prognosis
Comparator / control treatment
No control. All patients recruited are undergoing a general anaesthetic for the surgical procedure
Control group
Uncontrolled

Outcomes
Primary outcome [1] 296044 0
The primary outcome will be identifying whether measuring airway collapsibility measurements are feasible and repeatable in children undergoing tonsillectomy procedures.
Timepoint [1] 296044 0
Measurements will be completed at 3 time points during the anaesthetic time for the surgical procedure.
(1) Just after induction of anaesthesia and prior to insertion of the airway device
(2) At emergence of anaesthesia, once the procedure is completed and just after the removal of the airway device
(3) In the recovery phase of anaesthesia, prior to the patient being awake.
Secondary outcome [1] 317345 0
The secondary exploratory outcome will be the associations between the presence and extent of airway collapse and the presence and/or severity of obstructive sleep apnoea.
presence/extent of airway collapse assessed by pressure transducer in nasal mask, and OSA assessed by the PMH Sleep disturbance scale for children completed by parent/carer.
Timepoint [1] 317345 0
Measurements will be completed at 3 time points during the anaesthetic time for the surgical procedure.
(1) Just after induction of anaesthesia and prior to insertion of the airway device
(2) At emergence of anaesthesia, once the procedure is completed and just after the removal of the airway device
(3) In the recovery phase of anaesthesia, prior to the patient being awake.
Secondary outcome [2] 317346 0
The secondary exploratory outcome will be the associations between the presence and extent of airway collapse and the incidence of perioperative respiratory adverse events (PRAE).
Presence/extent of airway collapse assessed by pressure transducer in nasal mask, and respiratory adverse events as assessed by the anaesthetist throughout the procedure (including bronchospasm, laryngospasm, airway obstruction, severe coughing, oxygen desaturation or stridor).
Timepoint [2] 317346 0
Measurements will be completed at 3 time points during the anaesthetic time for the surgical procedure.
(1) Just after induction of anaesthesia and prior to insertion of the airway device
(2) At emergence of anaesthesia, once the procedure is completed and just after the removal of the airway device
(3) In the recovery phase of anaesthesia, prior to the patient being awake.
PRAE will be monitored and documented at induction of anaesthesia, during maintenance and emergence of anaesthesia and at the recovery stage after anaesthesia.

Eligibility
Key inclusion criteria
Male or female
Aged 1 to 8 years of age
Undergoing elective surgery under general anaesthetic for tonsillectomy (+/- adenoids, myringotomy, and/or cautery of inferior turbinates)
Minimum age
1 Years
Maximum age
8 Years
Gender
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Need for premedication with midazolam.
Contraindication for the use of sevoflurane
Inability to give informed consent
Children with known cardiopulmonary disease
Significant medical disease or condition that is likely to interfere with the protocol or might be confounded by the protocol.

Study design
Purpose of the study
Diagnosis
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
All participants will be recruited at the pre-anaesthetic visit. The treating anaesthetists approval will be sought prior to any participants being approached. Only patients who meet the inclusion criteria for the study will be enrolled and only after written informed consent is given voluntarily by the guardian and by the patient if appropriate.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
No randomisation
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Single group
Other design features
N/A
Phase
Not Applicable
Type of endpoint(s)
Safety/efficacy
Statistical methods / analysis
Exploratory analysis, which will be used to inform future studies, will examine the relationships the presence and extent of airway collapsibility and the presence of OSA and the presence and extent of PRAE. Poisson or negative binomial regression methods will be used to analyse the relationship between the critical pressure at which the airway tends to collapse and the rate of occurrence of PRAE. No interim analysis is planned for the 50 patients that are going to be recruited in this pilot study. The level of significance will be set at 0.05.

Due to the unavailability of paediatric data in regards to this project, our design is of pilot nature. Therefore based on the anterior lung function feasibility studies our team has carried out in theatre environment and the expertise of our chief investigators in achieving airway collapsibility measurements in an adult population, 50 successful measurements in participants aged 1 to 8 years should allow us to verify our primary hypothesis. From our significant experience recruiting and measuring in the paediatric anaesthesia trials, we will need to account for 10% of unusable data due to potential patient withdrawals, loss of data due to technical issues or due to changing anaesthesia management. Therefore 56 patients will have to be recruited for the study.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
WA
Recruitment hospital [1] 4310 0
Princess Margaret Hospital - Subiaco
Recruitment postcode(s) [1] 10466 0
6008 - Subiaco

Funding & Sponsors
Funding source category [1] 292000 0
Charities/Societies/Foundations
Name [1] 292000 0
Princess Margaret Hospital Foundation
Address [1] 292000 0
Princess Margaret Hospital Foundation
68 Hay Street
Subiaco
WA 6008
Country [1] 292000 0
Australia
Primary sponsor type
Individual
Name
Prof Britta Regli-von Ungern-Sternberg
Address
Department of Anaesthesia and Pain Management
Princess Margaret Hospital
Roberts Road
Subiaco
WA 6008
Country
Australia
Secondary sponsor category [1] 290663 0
Hospital
Name [1] 290663 0
Princess Margaret Hospital
Address [1] 290663 0
Department of Anaesthesia and Pain Management
Princess Margaret Hospital
Roberts Road
Subiaco
WA 6008
Country [1] 290663 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 293488 0
Princess Margaret Hospital Ethics Committee
Ethics committee address [1] 293488 0
Roberts Road,
Subiaco
WA 6008
Ethics committee country [1] 293488 0
Australia
Date submitted for ethics approval [1] 293488 0
23/06/2015
Approval date [1] 293488 0
16/09/2015
Ethics approval number [1] 293488 0
EP/2015140

Summary
Brief summary
Obstructive sleep apnoea (OSA) is a condition involving repeated episodes of partial or complete blockage of the airway during sleep. Learning difficulties, behavioural problems as well as bed-wetting, sleep-walking, retarded growth, other hormonal and metabolic problems and even failure to thrive can be related to sleep apnoea. Children diagnosed with OSA usually undergo surgical removal of the tonsils and adenoids.
However, there is a high rate of complications with approximately 50% of the children suffering from minor or major breathing problems during and/or after surgery requiring specialised care. Additionally, the younger the children are, the higher the risk of breathing problems, which have a potential for serious harm to their health.
The impact on the healthcare system is significant; the number of unplanned admissions necessitating specialised treatment with prolonged hospital stays increases causing delays on theatre lists. This leads to potential cancellations of other children due to the lack of theatre time and consequently increases the waitlist time.
Currently the pre-operative assessment by the ENT surgeon determines whether the child will be managed as a day case or a ward patient. In case of the latter, it is further distinguished if the child gets normal ward care, specialised ward care or whether an admission to the intensive care unit is required. If the child has not been sent to the preoperative anaesthetic clinic (which is the case for the majority of children), the anaesthetist on the day of surgery might need to organise more specialised care if he/she does not agree with the care pre-organised, which may lead again to cancellations. Currently, preoperative assessment relies heavily on the surgeons and the anaesthetists’ pre-operative diagnosis. It usually involves using a clinical questionnaire that relies mostly on parental observation and interpretation of symptoms to accurately identify the presence of OSA and grade its severity accordingly. Once the grade of OSA has been established, the risk of perioperative respiratory complications can be better established and preventative strategies can be implemented where deemed necessary. However the rate of complication and unplanned admissions remain high. This is due to the grading of OSA being impacted by the high variability in the answers to the clinical questionnaire; different parents interpret the same symptoms differently and thus introduce a high bias in the OSA grading.
A more appropriate approach to diagnosis and grading OSA with a much higher degree of accuracy would be the use of a scientific marker that can easily, quickly and safely be measured at the point of care. It is well known and has been shown in the literature that children with OSA have upper airways that are more prone to collapse during sleep and thus anaesthesia. Thus measuring the propensity of upper airway collapse may provide the treating team with more accurate physiological data to grade OSA and consequently narrow down the variability in the estimated probability of perioperative respiratory adverse events.
Our team of respiratory and sleep physiology experts have developed and trialled a quick, safe and easy technique to measurement the propensity of upper airway collapsibility in adults and with this study we are aiming to identify whether this technique can be used in everyday clinical practice during peri-operative management to screen children with OSA who are at a higher risk of perioperative respiratory adverse events (PRAE).
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 60110 0
Prof Britta Regli-von Ungern-Sternberg
Address 60110 0
Department of Anaesthesia and Pain Management,
Princess Margaret Hospital for Children,
Roberts Road,
Subiaco WA 6008
Country 60110 0
Australia
Phone 60110 0
+61 8 93408109
Fax 60110 0
Email 60110 0
britta.regli-vonungern@health.wa.gov.au
Contact person for public queries
Name 60111 0
Prof Britta Regli-von Ungern-Sternberg
Address 60111 0
Department of Anaesthesia and Pain Management,
Princess Margaret Hospital for Children,
Roberts Road,
Subiaco WA 6008
Country 60111 0
Australia
Phone 60111 0
+61 8 93408109
Fax 60111 0
Email 60111 0
britta.regli-vonungern@health.wa.gov.au
Contact person for scientific queries
Name 60112 0
Prof Britta Regli-von Ungern-Sternberg
Address 60112 0
Department of Anaesthesia and Pain Management,
Princess Margaret Hospital for Children,
Roberts Road,
Subiaco WA 6008
Country 60112 0
Australia
Phone 60112 0
+61 8 93408109
Fax 60112 0
Email 60112 0
britta.regli-vonungern@health.wa.gov.au

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary