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Trial registered on ANZCTR


Registration number
ACTRN12611000026921
Ethics application status
Approved
Date submitted
5/01/2011
Date registered
10/01/2011
Date last updated
11/06/2011
Type of registration
Prospectively registered

Titles & IDs
Public title
Comparison of the reliability of continuous with intermittent blood pressure monitoring during Caesarean section under spinal anaesthesia
Scientific title
Comparison of the reliability of CNAP (continuous noninvasive arterial pressure) monitoring vs NIBP (noninvasive intermittent blood pressure) monitoring in providing minutely blood pressure readings during elective Caesarean section under spinal anaesthesia
Secondary ID [1] 253346 0
There are no secondary IDs.
Universal Trial Number (UTN)
U1111-1118-8174
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
The ability to provide a blood pressure reading every one minute during elective Caesarean section, until delivery, under spinal anaesthesia 258882 0
Condition category
Condition code
Anaesthesiology 259022 259022 0 0
Anaesthetics

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Two blood pressure devices will be compared. One is an automated arm cuff oscillometer or NIBP (noninvasive intermittent blood pressure) monitor that will be worn on the left arm. The second is a continuous blood pressure monitor that uses a finger cuff called CNAP (continuous noninvasive arterial pressure). This will be worn on the right hand. The NIBP will be set to inflate every one minute between the time of spinal anaesthesia and delivery of the baby (approximately 15 minutes). The CNAP will run continuously but it automatically calibrates every 15 minutes. During recalibration there is a period of 1-2 minutes in which it does not provide a blood pressure reading. The study ceases at delivery for each woman. After delivery, the CNAP monitor will be removed and the NIBP cuff will be set to inflate at a reduced frequency of once per 3-5 minutes.
Intervention code [1] 257793 0
Treatment: Devices
Comparator / control treatment
Each woman will be her own control and have the two devices running simultaneously.
Control group
Uncontrolled

Outcomes
Primary outcome [1] 259875 0
The ability to measure and provide a blood pressure reading every one minute between spinal anaesthesia and delivery of the baby. The time of spinal anaesthesia will be considered time zero. At each whole minute interval after time zero, until delivery, it will be noted if each blood pressure device provided a reading of systolic, diastolic and mean blood pressure within the preceeding minute or not. For each patient and for each device a reliability score will be calculated.

Reliability = number of minutes in which systolic, diastolic and mean blood pressure were provided/ number of minutes between spinal anaesthesia and delivery of baby x 100

The 'Trends analysis' on the Draeger Infinity patient monitor allows review of patient data on a one minute basis.
Timepoint [1] 259875 0
The duration of the study for each participant is during her Caesarean section until the time of delivery. The duration of the study overall will be approximately March - June 2011.
Secondary outcome [1] 268751 0
Nil
Timepoint [1] 268751 0
Nil

Eligibility
Key inclusion criteria
Elective Caesarean section under spinal anaesthesia
Minimum age
18 Years
Maximum age
45 Years
Gender
Females
Can healthy volunteers participate?
No
Key exclusion criteria
Hypertensive disorder of pregnancy
Peripheral vascular disease
Conversion to general anaesthesia prior to delivery
Caesarean prior to 32 weeks gestation

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)
Women will be recruited on the day of Caesarean. Each woman will have both blood pressure devices running simultaneously so she will act as her own control.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
N/A
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Single group
Other design features
Phase
Type of endpoint(s)
Safety/efficacy
Statistical methods / analysis

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)

Funding & Sponsors
Funding source category [1] 258267 0
Self funded/Unfunded
Name [1] 258267 0
Thomas McCarthy
Address [1] 258267 0
The Royal Women's Hospital
Department of Anaesthesia
Corner Flemington Rd and Grattan St
Locked bag 300
Parkville
VIC 3052
Country [1] 258267 0
Australia
Primary sponsor type
Individual
Name
Thomas McCarthy
Address
Department of Anaesthesia
The Royal Womens Hospital
cnr Flemington Rd and Grattan St
Locked bag 300
Parkville
VIC 3052
Country
Australia
Secondary sponsor category [1] 257433 0
None
Name [1] 257433 0
Address [1] 257433 0
Country [1] 257433 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 260242 0
The Royal Women's Hospital Human Research Ethics Committee
Ethics committee address [1] 260242 0
Research and Ethics Secretariat
The Royal Womens Hospital
cnr Flemington Rd and Grattan St
Locked bag 300
Parkville
VIC 3052
Ethics committee country [1] 260242 0
Australia
Date submitted for ethics approval [1] 260242 0
19/01/2011
Approval date [1] 260242 0
15/03/2011
Ethics approval number [1] 260242 0

Summary
Brief summary
This project proposes to compare two methods of measuring women’s blood pressure during elective Caesarean sections. The safest and most common type of anaesthetic for a Caesarean section is a spinal anaesthetic. This abolishes painful sensation from the surgery and allows the woman to stay awake while her baby is delivered. However, a common side effect of a spinal anaesthetic is low blood pressure which can cause nausea and vomiting for the mother and may be harmful to the foetus. The pH (acidity) of blood from the umbilical cord taken immediately after delivery is lower (more acidic) if there has been low maternal blood pressure during the Caesarean.
Blood pressure is closely monitored by the anaesthetist immediately after the spinal anaesthetic and a drug called metaraminol is given to increase the blood pressure if it is low. Metaraminol works by constricting blood vessels. The most common way of measuring blood pressure is with an automatic cuff on the arm called a noninvasive blood pressure (NIBP) device. This may be set to inflate every one, two or three minutes. However, the reliability of NIBP devices is poor and sometimes they fail to provide a blood pressure reading when required. This is a problem when the blood pressure is so variable in a short time period.
An alternative device can provide continuous noninvasive arterial pressure (CNAP) measurement. It measures blood pressure using small cuffs on the finger. This study proposes to compare the reliability of the NIBP device with the CNAP device. Reliability is defined as the ability to provide a blood pressure reading every one minute during a Caesarean section. The main aim is not to compare the accuracy of these two devices. This is already well described in other research. The CNAP device often needs to recalibrate (at least every 15 minutes) and during this period, lasting between 40 and 180 seconds, no blood pressure readings are provided. It is therefore unknown which device is more reliable.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 32051 0
Address 32051 0
Country 32051 0
Phone 32051 0
Fax 32051 0
Email 32051 0
Contact person for public queries
Name 15298 0
Thomas McCarthy
Address 15298 0
Department of Anaesthesia
The Royal Womens Hospital
cnr Flemington Rd and Grattan St
Locked bag 300
Parkville
VIC 3052
Country 15298 0
Australia
Phone 15298 0
+61 3 83452385
Fax 15298 0
Email 15298 0
thomas.mccarthy@thewomens.org.au
Contact person for scientific queries
Name 6226 0
Thomas McCarthy
Address 6226 0
Department of Anaesthesia
The Royal Womens Hospital
cnr Flemington Rd and Grattan St
Locked bag 300
Parkville
VIC 3052
Country 6226 0
Australia
Phone 6226 0
+61 3 83452385
Fax 6226 0
Email 6226 0
thomas.mccarthy@thewomens.org.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