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Trial registered on ANZCTR


Registration number
ACTRN12607000413426
Ethics application status
Not yet submitted
Date submitted
5/08/2007
Date registered
13/08/2007
Date last updated
13/08/2007
Type of registration
Prospectively registered

Titles & IDs
Public title
Blood pressure – during general anaesthesia versus sleep
Scientific title
In healthy adults undergoing surgery, how does general anaesthesia compared to sleep affect blood pressure.
Universal Trial Number (UTN)
Trial acronym
BGAS
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Hypotension 2219 0
Condition category
Condition code
Anaesthesiology 2310 2310 0 0
Other anaesthesiology

Intervention/exposure
Study type
Observational
Patient registry
Target follow-up duration
Target follow-up type
Description of intervention(s) / exposure
Hypotension/changes in blood pressure that occur during general anaesthesia (for duration of anaesthetic) compared to normal everyday life for a 24 hour period (including sleep)
Intervention code [1] 1930 0
Treatment: Other
Comparator / control treatment
Normal everyday life
Control group

Outcomes
Primary outcome [1] 3207 0
Mean arterial pressure
Timepoint [1] 3207 0
Timepoints:
-at baseline (during sleep)
-at 5 minutely intervals during general anaesthesia
Secondary outcome [1] 5346 0
Systolic and diastolic blood pressure
Timepoint [1] 5346 0
Timepoints:
- at baseline
- at 5 minutely intervals during anaesthesia

Eligibility
Key inclusion criteria
Patients undergoing peripheral surgery (ie. not cardiothoracic or intra-abdominal) of ASA (American Society of Anaesthesiologists) score 1 or 2 (ie. ASA 1 = a normal healthy patient or ASA 2 = a patient with mild systemic disease).
Minimum age
18 Years
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Patients who are unsuitable for wearing an automated blood pressure device or unable to give informed consent due to cognitive reasons or language barriers. Patients with physical factors not permitting the wearing of an automated blood pressure monitor.

Study design
Purpose
Natural history
Duration
Cross-sectional
Selection
Convenience sample
Timing
Prospective
Statistical methods / analysis

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
4/02/2008
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
40
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)

Funding & Sponsors
Funding source category [1] 2476 0
Hospital
Name [1] 2476 0
St Vincent's Hospital
Country [1] 2476 0
Australia
Primary sponsor type
Individual
Name
Dr Jaclyn Soo
Address
Country
Secondary sponsor category [1] 2249 0
Individual
Name [1] 2249 0
Dr Sally Lacey
Address [1] 2249 0
Country [1] 2249 0
Secondary sponsor category [2] 2250 0
Individual
Name [2] 2250 0
Dr Brendan Silbert
Address [2] 2250 0
Country [2] 2250 0

Ethics approval
Ethics application status
Not yet submitted
Ethics committee name [1] 4380 0
St Vincent's Health HREC
Ethics committee address [1] 4380 0
Ethics committee country [1] 4380 0
Date submitted for ethics approval [1] 4380 0
Approval date [1] 4380 0
Ethics approval number [1] 4380 0

Summary
Brief summary
A person’s normal blood pressure changes throughout the day, typically being higher during the awake hours and lower during the hours when a person is asleep. There are many factors that could also change the blood pressure during the day: level of activity, pain, stress, disease, hormones, hydration etc.

One reliable way of measuring all the daily changes in blood pressure is a device called Ambulatory Blood Pressure Monitor (ABPM). ABPM units indirectly measure blood pressure through vibrational signals associated with blood flow in the artery in the elbow, when a blood pressure cuff is inflated and then deflated. These are non-invasive, automated, lightweight, and are typically battery powered, belt-worn, and of a size and shape similar to that of a walkman or portable CD player. There may be mild discomfort when the blood pressure is being measured, however, this is only brief. With ABPM, multiple automatic measurements of blood pressure are obtained at specific intervals throughout a 24 to 48 hour period, and this information is recorded onto a computer chip, which could be printed out for analysis by a doctor.

Blood pressure is one of the parameters routinely monitored when an anaesthetic is given for any operation or procedure. When a person undergoes an anaesthetic, there are many factors that could decrease blood pressure, including the medications that are given. It is usually treated with fluid, or other medications, when the blood pressure is lower than the initial blood pressure measured. However, there has been no study that has looked at how much a person’s blood pressure normally decreases when a person is asleep in comparison with their blood pressure under anaesthesia. Patients may well be treated for low blood pressure during anaesthesia (albeit unnecessarily) despite the possibility that their blood pressure may actually reach lower levels during sleep.

To investigate this further, we propose to follow a group of fit and well patients (ie. No pre-existing blood pressure problems) undergoing minor general surgery. They will be fitted with an ABPM for 24 hours when they come to hospital for their pre-admission appointments. When they re-present for operation, their blood pressure under anaesthesia will be recorded (by both the ABPM, and routine BP monitoring), and compared to their normal “asleep” blood pressure. The presence of the ABPM will not affect the patient’s surgery or other management in any way.

It is hoped that by establishing a relationship between a person’s normal asleep blood pressure and that during anaesthesia will better enable doctors to manage their patients.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 27744 0
Address 27744 0
Country 27744 0
Phone 27744 0
Fax 27744 0
Email 27744 0
Contact person for public queries
Name 11119 0
Jaclyn Soo
Address 11119 0
Department of Anaesthesia
St Vincent's Hospital
55 Victoria Parade
PO Box 2900
Fitzroy VIC 3065
Country 11119 0
Australia
Phone 11119 0
(03) 9288 2211
Fax 11119 0
Email 11119 0
[email protected]
Contact person for scientific queries
Name 2047 0
Jaclyn Soo
Address 2047 0
Department of Anaesthesia
St Vincent's Hospital
PO Box 2900
55 Victoria Parade
Fitzroy VIC 3065
Country 2047 0
Australia
Phone 2047 0
(03) 9288 2211
Fax 2047 0
Email 2047 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

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