Arm and Ankle Blood Pressure Cuffs During C-Section

Study Overview
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Brief Summary
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This is a single center prospective self-control study to validate the effectiveness of left uterine displacement after subarachnoid block (SAB) with simultaneous measurements of blood pressure (BP) on the arm and left ankle during surgery in patients undergoing cesarean delivery (CD) at The Ohio State University Wexner Medical Center

Detailed Description
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In the last three decades, numerous interventions have been studied and implemented into our daily practice, such as pre-loading versus co-loading, phenylephrine versus ephedrine, and phenylephrine infusion versus intermittent boluses. In addition, the effectiveness of left uterine displacement (LUD) to improve blood flow and pressure remains unclear. Also, there are issues to be addressed on this regard, including: Poor placental perfusion from inadequate LUD due to the potential impact of supine hypotensive syndrome (SHS) secondary to aortocaval compression especially after SAB; Shivering during cesarean delivery (CD) resulting in inaccurate BP measurements, the incidence of shivering during CD is reported to be 21.9%. It is unclear the impact of shivering during CD on blood pressure (BP) measurements; Patient discomfort during BP measurements, calf > arm > ankle The Investigators are conducting a single center prospective self-control study aiming to validate the effectiveness of LUD after SAB with simultaneous measurements of BP on the arm and left ankle during surgery in patients undergoing cesarean delivery (CD). In addition, the Investigators will determine whether ankle BP correlates more accurately than arm SBP with the incidence of nausea/vomiting and category II or III fetal heart tracing and bradycardia after SAB and LUD under no shivering conditions and the impact of body mass index and antepartum estimation of newborn weight on SHS after the SAB.

Official Title
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Comparison of Arm and Ankle Blood Pressure During Cesarean Delivery: A Blood Pressure Cuffs Pilot Study

Conditions
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Supine Hypotensive Syndrome, Cesarean Section Complications, Anesthesia Complication

Intervention / Treatment
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* Other: Blood Pressure Cuff


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age ≥ 18 years old Women undergoing cesarean delivery at The Ohio State University Wexner Medical Center under spinal anesthesia American Society of Anesthesiologists Physical Status I-III Body mass index during pregnancy ≥ 35 kg/m2 Able to consent in English language Singleton pregnancy Exclusion Criteria: Women undergoing elective cesarean delivery at The Ohio State University Wexner Medical Center under anesthesia other than spinal anesthesia (i.e. general and/or epidural anesthesia) Prisoners

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Study Population<br>Adult women undergoing cesarean delivery at The Ohio State University Wexner Medical Center under spinal anesthesia, ASA physical status I-III with a BMI during pregnancy ≥ 35 kg/m2 and singleton pregnancy. | Other: Blood Pressure Cuff<br>* After obtaining consent and confirming eligibility, Blood Pressure cuffs will be used as specified below: Cuff size: large BP cuffs will be the default size for both arm and ankle measurements, but can be changed as clinically indicated based on circumferences of limbs Cuff location: BP cuffs will be placed on the contralateral arm to the main peripheral IV following standard procedures. Left ankle cuff will be placed underneath intermittent pneumatic compression cuffs Ankle blood pressure monitor screen will be covered. Thus, anesthesia providers will not be able to make any clinical decisions based on ankle blood pressures but arm blood pressure (standard) instead.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Difference of SBP measured between arm and ankle during elective CD before SAB | Arm Systolic Blood Pressure values will be compared with the ankle SBP values before subarachnoid anesthesia. Baseline SBP will be measured pre-spinal anesthesia in supine position (after standard of care left uterine displacement maneuver is performed). | Immediately before subarachnoid anesthesia block (after standard of care left uterine displacement maneuver is performed). | 
| Difference of SBP measured between arm and ankle during elective CD after SAB (before incision) | Arm Systolic Blood Pressure values will be compared with the ankle SBP values after subarachnoid anesthesia. Postspinal SBP will be measured in supine position, after LUD is performed | Immediately after subarachnoid anesthesia block is completed | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of intraoperative nausea in our patient population | the incidence of intraoperative nausea will be assessed during anesthesia and surgery | Up to 3 hours from OR admission. Immediately before anesthesia (subarachnoid block) and until operating room discharge | 
| Incidence of intraoperative vomiting in our patient population | the incidence of intraoperative vomiting will be assessed during anesthesia and surgery | Up to 3 hours from OR admission. Immediately before anesthesia (subarachnoid block) and until operating room discharge |