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Trial registered on ANZCTR


Registration number
ACTRN12614000424606
Ethics application status
Approved
Date submitted
3/04/2014
Date registered
17/04/2014
Date last updated
30/01/2017
Type of registration
Prospectively registered

Titles & IDs
Public title
Obesity: Alterations in lung mechanics - impact on the incidence of perioperative respiratory adverse events (OPRAE)
Scientific title
In children receiving a general anaesthetic will obese or overweight children have differences in the incidence of perioperative respiratory adverse events and have alterations in lung mechanics compared to normal weight children?
Secondary ID [1] 284394 0
Nil
Universal Trial Number (UTN)
Trial acronym
OPRAE
Linked study record

Health condition
Health condition(s) or problem(s) studied:
The impact of obesity on the incidence of perioperative respiratory adverse events and the alterations in lung mechanics compared to normal weight children. 291570 0
Condition category
Condition code
Anaesthesiology 291948 291948 0 0
Anaesthetics
Respiratory 291949 291949 0 0
Normal development and function of the respiratory system
Diet and Nutrition 292063 292063 0 0
Obesity

Intervention/exposure
Study type
Observational
Patient registry
False
Target follow-up duration
Target follow-up type
Description of intervention(s) / exposure
All participants will be recruited at the preanaesthetic visit and will be consented voluntarily to the study after approval from the consulting anaesthetist.
Children’s weight, height and age will be used to calculate their BMI percentile to assign them to the two study groups:
*Group 1, normal weight: patients aged between 6 and 16 years with a BMI above the 5th percentile and below the 85th percentile
*Group 2, overweight/obese: patients aged between 6 and 16 years with a BMI greater than or equal to the 85th percentile.
Each patient will complete Lung function testing which will involve two different tests before anaesthesia induction: the measurement of respiratory mechanics using the forced oscillation technique and lung volumes using the multiple breath washout technique. The forced oscilation technique will be repeated after anaesthesia induction. Patients will be monitored throughout their procedures and postoperatively in the post anaesthesia care unit (PACU). Any respiratory complications that may occur will be documented. Patients will be followed up on the ward or via telephone within 3 days following surgery incase of any complications.
Intervention code [1] 289125 0
Not applicable
Comparator / control treatment
The obese/overweight children will be compared to the normal weight children as defined by the BMI percentile:
*Group 1, normal weight – patients aged between 6 and 16 years with a BMI above 5th percentile and below 85th percentile
*Group 2, overweight/obese – patients aged between 6 and 16 years with a BMI greater than or equal to the 85th percentile.
Control group
Active

Outcomes
Primary outcome [1] 291854 0
The primary outcome is to assess the incidence of Perioperative Respiratory Adverse Events between children who are overweight/obese and children who have a normal weight.
These respiratory adverse events include laryngospasm, bronchospasm, desaturation <95%, airway obstruction, severe coughing and/or postoperative stridor as assessed by the treating anaesthetist and in recovery by the treating nurses.
Timepoint [1] 291854 0
The Respiratory adverse events will be recorded at anaesthesia induction, maintenance, emergence and in recovery.
Secondary outcome [1] 307670 0
The secondary outcome is to compare the effects of postural changes in lung volumes and respiratory mechanics between children who are overweight/obese and children who have a normal weight.
Timepoint [1] 307670 0
These outcomes will be measured using the forced ocsilation technique prior to and after anaesthesia induction and by using the multiple breath washout technique prior to anaesthesia induction.

Eligibility
Key inclusion criteria
*Children undergoing elective surgery
*Male or Female aged between 6 and 16 years
*Children with a BMI more than the 5th and less than the 85th percentile (normal weight group)
*Children with a BMI more than or equal to 85th percentile (overweight and obese group)
*Children having a laryngeal mask airway (LMA).
Minimum age
6 Years
Maximum age
16 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
*Children with a known cardiopulmonary disease:
*Uncorrected congenital heart disease
*Primary/secondary pulmonary hypertension
*Cardiac/thoracic malformations/tumours
*Structural lung changes
*Airway malformations, thorax deformity
*Children unable to perform the lung function tests.
*Children receiving a sedating premedication (e.g. midazolam, clonidine) before surgery.
*Children having used a bronchodilator within 5 hours prior to surgery.
*Children having an endotracheal tube inserted during anaesthesia
The above list is not an exhaustive list. Other less common cardiopulmonary conditions will be assessed by the anaesthetist in charge in consulation with the study team.

Study design
Purpose
Screening
Duration
Cross-sectional
Selection
Defined population
Timing
Prospective
Statistical methods / analysis
To detect the effect size in this study, we will need 44 obese/overweight children and 44 normal weight children to have a statistical power of 0.8 at the significance of 0.05. The sample size and power were estimated in STATA environment. Furthermore, based on our research experience protocol violations, poor quality data and patient withdrawals are common factors that have a significant influence on the sample size of a study. These need to be included in the final sample size calculation in order to obtain 44 usable datasets per group. We estimate these factors to account for approximately 25% of each cohort, thus leading to a sample size of 110 children divided into 2 groups of 55.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
21/04/2014
Actual
25/11/2014
Date of last participant enrolment
Anticipated
30/12/2016
Actual
10/01/2017
Date of last data collection
Anticipated
Actual
10/01/2017
Sample size
Target
110
Accrual to date
Final
110
Recruitment in Australia
Recruitment state(s)
WA
Recruitment hospital [1] 2293 0
Princess Margaret Hospital - Subiaco
Recruitment postcode(s) [1] 7971 0
6008 - Subiaco

Funding & Sponsors
Funding source category [1] 289037 0
Charities/Societies/Foundations
Name [1] 289037 0
Princess Margaret Hospital Foundation
Country [1] 289037 0
Australia
Funding source category [2] 292443 0
Other
Name [2] 292443 0
Australia and New Zealand College of Anaesthetists
Country [2] 292443 0
Australia
Funding source category [3] 292444 0
Government body
Name [3] 292444 0
NHMRC
Country [3] 292444 0
Australia
Primary sponsor type
Individual
Name
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] 287710 0
None
Name [1] 287710 0
Address [1] 287710 0
Country [1] 287710 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 290837 0
Princess Margaret Hospital for Children Ethics Committee
Ethics committee address [1] 290837 0
Level 1, Children's Clinical Research Facility
Princess Margaret Hospital
Roberts Road, Subiaco
Perth
WA 6008
Ethics committee country [1] 290837 0
Australia
Date submitted for ethics approval [1] 290837 0
07/10/2013
Approval date [1] 290837 0
16/04/2014
Ethics approval number [1] 290837 0
2013110

Summary
Brief summary
Despite the development of anaesthesia management guidelines, perioperative respiratory adverse events (PRAE) remain a major cause of morbidity and mortality during paediatric anaesthesia, causing more than three quarters of critical incidents and nearly one third of all perioperative cardiac arrests.
In paediatric anaesthesia, obesity is a significant problem with obese children not only having anaesthesia-relevant co-existing diseases like asthma or hypertension, but also having a higher incidence of anaesthesia related complications. Many factors encountered during general anaesthesia such as supine positioning (lying down, face up), anaesthetic agents and the type of surgery affect the functioning of the respiratory system and in particular lung volumes and respiratory mechanics. These anaesthesia related changes in lung function are expected to be even more pronounced in obese patients. The incidence of obesity is rising steadily in Australia with 25% of children being overweight or obese in 2011-2012 according to the Australian Bureau of Statistics.
A better knowledge of lung health and the changes in lung function caused by anaesthesia and the impairment of respiratory mechanics by obesity will help improve the management of these high risk patients.
We therefore aim to assess lung function changes as well as the incidence of PRAE in healthy and overweight/obese children.
We hypothesise that
1.The incidence of PRAE will be higher in obese/overweight children compared to normal weight children.
2.Obese or overweight children will have a significantly different respiratory resistance (Rrs) and reactance (Xrs) compared to normal weight children.
3.The state of consciousness (being awake or anaesthetised) and the body position (being seated or supine) will affect the respiratory resistance and reactance and that this effect with be more pronounced in overweight and obese children compared to children with a healthy weight.

We will recruit 110 children between the ages of 6 and 16 that have a BMI between the 5th and 85th percentile for the healthy population (n equal to 55) and more than or equal to the 85th percentile for the obese/overweight population (n equal to 55). Lung function testing consisting of Forced Oscillation Technique (FOT) and Multiple Breath Washout (MBW) will be completed on all patients on the day of their procedure. All patients will be monitored closely during and following their procedures and any respiratory events will be recorded.

We are hoping to get a better understanding of the lung health of the obese and overweight population of children in order to improve the anaesthetic management of this high risk group.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 47526 0
Prof Britta Regli-von Ungern-Sternberg
Address 47526 0
Department of Anaesthesia and Pain Management
Princess Margaret Hospital for Children
Roberts Road,
Subiaco
WA 6008
Country 47526 0
Australia
Phone 47526 0
+61893408109
Fax 47526 0
Email 47526 0
[email protected]
Contact person for public queries
Name 47527 0
Britta Regli-von Ungern-Sternberg
Address 47527 0
Department of Anaesthesia and Pain Management
Princess Margaret Hospital for Children
Roberts Road,
Subiaco
WA 6008
Country 47527 0
Australia
Phone 47527 0
+61893408109
Fax 47527 0
Email 47527 0
[email protected]
Contact person for scientific queries
Name 47528 0
Britta Regli-von Ungern-Sternberg
Address 47528 0
Department of Anaesthesia and Pain Management
Princess Margaret Hospital for Children
Roberts Road,
Subiaco
WA 6008
Country 47528 0
Australia
Phone 47528 0
+61893408109
Fax 47528 0
Email 47528 0
[email protected]

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