Can Augmentation Index (AIx) be Used to Predict Hypotension After Spinal Anesthesia?
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|ClinicalTrials.gov Identifier: NCT00884026|
Recruitment Status : Completed
First Posted : April 20, 2009
Last Update Posted : January 23, 2013
|Condition or disease||Intervention/treatment||Phase|
|Hypotension Cesarean Delivery||Device: AIx measurement with a Sphygmacor TM||Not Applicable|
At BC Women's Hospital (BCWH), anesthesiologists give spinal anesthesia for most elective cesarean deliveries. When the spinal medication is given, blood vessels expand in reaction to the spinal medication causing blood pressure to fall. If a patient experiences this common reaction, the anesthesiologist would administer some medications to restore blood pressure to normal. They do this to protect the blood supply to the placenta and to the baby.
It is not known why this happens in some people and not in others. The way blood circulates through the body can provide information about changes occurring in the body. Pulse measurements are a simple way of providing physicians with important clinical information about patient health.
A device called a SphygmacorTM can be used to measure a pulse. The pulse measurement is called the Augmentation Index (AIx). AIx has been useful in detecting risks associated with blood pressure changes after complex surgery in patients with heart and blood vessel disease. In our study we wish to see if AIx can predict a normal patient's risk of hypotension after spinal anesthesia. If a trend between AIx and the onset of hypotension after spinal anesthesia can be found, anesthesiologists can more effectively prevent and treat hypotension by being able to predict whether it will occur.
Consenting subjects will have their blood pressure and AIx measurement taken prior to surgery.
Surgery will commence as per usual practice at BCWH. If hypotension occurs after the spinal anesthesia, anesthesiologist will treat as per usual practice.
Following recruitment and data collection on the first 30 subjects we will review their anesthetic records to assess whether they became hypotensive or not (systolic BP > 20% from baseline). This will give us two groups. Group 1 will be those subjects who developed hypotension, and Group 2 will be those subjects who did not develop hypotension. We will then look at the preoperative measured AIx to determine whether there is a baseline difference between the two groups. A threshold value of the AIx with the best sensitivity and specificity for prediction of hypotension will then be determined.
The second part of the study will then use the threshold AIx value found from the subjects who developed hypotension from the first 30 subjects to prospectively predict hypotension after spinal anesthesia in another 60 subjects.
|Study Type :||Interventional (Clinical Trial)|
|Actual Enrollment :||56 participants|
|Intervention Model:||Parallel Assignment|
|Masking:||Double (Participant, Investigator)|
|Official Title:||Pulse Wave Analysis and Augmentation Index Changes Associated With Neuraxial Anesthesia in the Parturient|
|Study Start Date :||March 2009|
|Actual Primary Completion Date :||March 2010|
|Actual Study Completion Date :||March 2010|
Active Comparator: 1
Subjects that experience hypotension after spinal anesthesia.
Device: AIx measurement with a Sphygmacor TM
All subjects will have their AIx measured prior to surgery. After 30 subjects are recruited, they will be split into 2 groups. Group 1 will be those subjects who developed hypotension, and Group 2 will be those subjects who did not develop hypotension. We will then look at the preoperative measured AIx to determine whether there is a baseline difference between the two groups. A threshold value of the AIx with the best sensitivity and specificity for prediction of hypotension will then be determined.
Active Comparator: 2
Subjects that do not experience hypotension after spinal anesthesia.
Device: AIx measurement with a Sphygmacor TM
The second part of the study will then use the threshold AIx value found from the subjects who developed hypotension from the first 30 subjects to prospectively predict hypotension after spinal anesthesia in another 60 subjects
- Occurrence of hypotension following spinal anesthesia. Defined as systolic BP > 20% from baseline. [ Time Frame: 1 week ]
- Augmentation Index as measured by the SphygmacorTM preoperatively; Bradycardia requiring pharmacological treatment; Ephedrine requirement; Phenylephrine requirement; Block Height; Nausea/vomiting [ Time Frame: 1 week ]
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00884026
|Canada, British Columbia|
|BC Women's Hospital Dept of Anesthesia|
|Vancouver, British Columbia, Canada|
|Principal Investigator:||Vit Gunka, MD, FRCPC||University of British Columbia|
|Study Director:||James Shannon, FCARSCI MSc||University of British Columbia|
|Study Director:||Joanne Douglas, MD, FRCPC||University of British Columbia|
|Study Director:||Jessica Tyler, BSc||University of British Columbia|