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Wrist NIBP During Elective Cesarean Delivery

This study has been completed.
Sponsor:
Information provided by (Responsible Party):
University of British Columbia
ClinicalTrials.gov Identifier:
NCT01677234
First received: August 29, 2012
Last updated: July 2, 2013
Last verified: July 2013
  Purpose

Blood pressure is typically measured with a non-invasive cuff placed on the upper arm. This cuff cannot take accurate measurements when the patient's arm is moving. Anesthesia for a cesarean delivery frequently causes the patient to shiver and their arm to shake, and sometimes to the extent that blood pressure cannot be measured. A cuff placed on the wrist may be more effective when a patient is shivering because their lower arm moves less and can be more easily stabilized. We will be taking simultaneous blood pressure measurements both just before and during cesarean deliveries in order to compare blood pressure at the upper arm versus the wrist.


Condition
Wrist Blood Pressure Measurements
Anesthesia Resulting in Shivering

Study Type: Observational
Study Design: Observational Model: Cohort
Time Perspective: Prospective
Official Title: Comparison of Arm and Forearm Blood Pressure During Elective Cesarean Delivery

Resource links provided by NLM:


Further study details as provided by University of British Columbia:

Primary Outcome Measures:
  • Compare trends in NIBP measurements between the upper arm and forearm [ Time Frame: 30 minutes ] [ Designated as safety issue: Yes ]
    Measure NIBP at the upper arm and forearm simultaneously during surgery. NIBP cuffs will be on opposite arms.


Secondary Outcome Measures:
  • To estimate the accuracy of blood pressure measured on the forearm [ Time Frame: 30 minutes ] [ Designated as safety issue: Yes ]

Enrollment: 71
Study Start Date: August 2012
Study Completion Date: May 2013
Primary Completion Date: May 2013 (Final data collection date for primary outcome measure)
Groups/Cohorts
Pregnant women
Pregnant women undergoing a cesarean section

Detailed Description:

Upper arm non-invasive blood pressure (NIBP) measurement is the most commonly accepted method of blood pressure (BP) monitoring. During a cesarean delivery it may be challenging to obtain an accurate measurement from the automated devices in over 50% of the attempts due to arm movement.1 Patients may voluntarily move their arm, but more often neuraxial (spinal, epidural, combined spinal-epidural) anesthesia is known to induce shivering that causes the patient's arm to shake.2 To eliminate the effect of movement of the upper arm, NIBP has been tested on the leg because it is immobilized during neuraxial anesthesia. However, studies monitoring NIBP on an ankle or a calf were unable to accurately detect changes (increase or decrease) in blood pressure in patients undergoing a cesarean delivery.3,4 It seems clinically reasonable that in the case of a shivering patient, the forearm, with less muscle mass, would shake less and could be stabilized more easily than the upper arm (stabilizing the forearm is easily done by holding the patient's hand with a light pressure on the arm rest). Therefore, positioning an NIBP cuff on the forearm (near the wrist) may be useful to obtain an accurate blood pressure measurement in shivering patients.

Previous studies have found that forearm BP overestimates blood pressure measured at the upper arm in a variety of clinical settings and patient populations under static (patient at rest, not submitted to an intervention that might alter BP) circumstances.5-8 It is unknown whether this overestimation is clinically relevant when blood pressure change occurs rapidly, such as during a cesarean delivery. During neuraxial anesthesia for cesarean delivery, it is important for the anesthesiologist to know both absolute values and clinically significant changes in blood pressure to determine their treatment. The detection of dynamic changes in blood pressure (as when the patient is submitted to an intervention that might alter BP per se, e.g. neuraxial anesthesia) has been studied in obstetric patients. Nevertheless, either due to the location where the BP cuff was placed4 (as on the lower limb with interference of the aorto-caval compression) or to the technology used to measure blood pressure,9 (the penaz technology was not consistent with oscillometric technology in a previous study) the forearm blood pressure was not comparable to upper arm blood pressure when measured using an oscillometric monitor.

This study will compare the upper arm (the current gold-standard) and the forearm NIBP measurements in patients undergoing an elective cesarean delivery under subarachnoid anesthesia. We hypothesize that the forearm systolic BP measurement values will be within 10% (lower or higher) of the systolic BP values measured in the upper arm at the same time-points

  Eligibility

Ages Eligible for Study:   19 Years and older
Genders Eligible for Study:   Female
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population

Women having an elective cesarean delivery at BC Women's Hospital in Vancouver, British Columbia.

Criteria

Inclusion Criteria:

  • Healthy (American Society of Anesthesiologist's (ASA) physical status I or II) patients
  • Having an elective cesarean delivery under spinal or combined spinal epidural anesthesia
  • ≥19 years old

Exclusion Criteria:

  • Contra-indication to neuraxial anesthesia
  • General anesthesia for any reason prior to delivery of the baby
  • Use of the epidural component (epidural top-up) of combined spinal epidural anesthesia (prior to delivery of the baby)
  • History of cardiovascular disease, e.g. hypertension (either essential or pregnancy-induced)
  • A difference of more than 10% between both upper arms and forearms in mean blood pressure measurement prior to surgery (see below)
  • BMI >35kg/m2 (it is more difficult to ensure the cuff size is correct in these obese patients)
  • Inability to read and understand English for the purpose of informed consent
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01677234

Locations
Canada, British Columbia
British Columbia's Women's Hospital
Vancouver, British Columbia, Canada, V6H 3N1
Sponsors and Collaborators
University of British Columbia
Investigators
Principal Investigator: Simon Massey, MD University of British Columbia, BC Women's Hospital
  More Information

No publications provided

Responsible Party: University of British Columbia
ClinicalTrials.gov Identifier: NCT01677234     History of Changes
Other Study ID Numbers: H12-01797
Study First Received: August 29, 2012
Last Updated: July 2, 2013
Health Authority: Canada: Health Canada

Keywords provided by University of British Columbia:
Blood pressure

ClinicalTrials.gov processed this record on November 20, 2014