ANZCTR - Registration

Please note the ANZCTR will be unattended from Friday 20 December 2024 for the holidays. The Registry will re-open on Tuesday 7 January 2025. Submissions and updates will not be processed during that time.

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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

Condition category

Condition code

Anaesthesiology

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]

Treatment: Other

Comparator / control treatment

Normal everyday life

Control group

Outcomes

Primary outcome [1]

Mean arterial pressure

Timepoint [1]

Timepoints:
-at baseline (during sleep)
-at 5 minutely intervals during general anaesthesia

Secondary outcome [1]

Systolic and diastolic blood pressure

Timepoint [1]

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?

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

Accrual to date

Final

Recruitment in Australia

Recruitment state(s)

Funding & Sponsors

Funding source category [1]

Hospital

Name [1]

St Vincent's Hospital

Address [1]

Country [1]

Australia

Primary sponsor type

Individual

Name

Dr Jaclyn Soo

Address

Country

Secondary sponsor category [1]

Individual

Name [1]

Dr Sally Lacey

Address [1]

Country [1]

Secondary sponsor category [2]

Individual

Name [2]

Dr Brendan Silbert

Address [2]

Country [2]

Ethics approval

Ethics application status

Not yet submitted

Ethics committee name [1]

St Vincent's Health HREC

Ethics committee address [1]

Ethics committee country [1]

Date submitted for ethics approval [1]

Approval date [1]

Ethics approval number [1]

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

Address

Country

Phone

Fax

Contact person for public queries

Name

Jaclyn Soo

Address

Department of Anaesthesia
St Vincent's Hospital
55 Victoria Parade
PO Box 2900
Fitzroy VIC 3065

Country

Australia

Phone

(03) 9288 2211

Fax

jaclyn.soo@svhm.org.au

Contact person for scientific queries

Name

Jaclyn Soo

Address

Department of Anaesthesia
St Vincent's Hospital
PO Box 2900
55 Victoria Parade
Fitzroy VIC 3065

Country

Australia

Phone

(03) 9288 2211

Fax

jaclyn.soo@svhm.org.au

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.

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