Measurement of Hemodynamic Variables Under Spinal Anesthesia With Varied Positioning

Study Overview
=================
Brief Summary
-----------------
Multiple studies have compared spinal anesthetic performed supine versus lateral, with varying results, in parturients having elective cesarean section. Needle positioning during spinal placement has also been examined. No positioning techniques have demonstrated definitive superiority for hemodynamic stability. Investigators propose that following spinal placement in the sitting position if the patient is placed in a lateral position for 90 seconds prior to turning them supine, hemodynamic changes caused by sympathectomy related to the subarachnoid block can be avoided. This is the first study to examining the influence of position changes after spinal anesthetic placement in the sitting position, which includes hemodynamic variables not previously studied including cardiac output, TPR (total peripheral resistance) and pulse pressure variation (PPV).

Detailed Description
-----------------
Cesarean section is chosen when natural spontaneous vaginal delivery is either not possible or when the health of the baby or mother is compromised. Cesarean section may be planned, urgent, or performed emergently when the life of the baby or mother is threatened. Cesarean section is performed using different anesthetic techniques including: spinal, epidural, combined spinal and epidural, and general anesthesia. Spinal anesthesia is the most common technique chosen due to its relative safety, rapid onset and avoidance of potential complications from general anesthesia. It is the technique of choice for elective cesarean section unless contraindicated. Spinal anesthesia causes sympathetic blockade followed by sensory and motor blockade. Nerve fiber size explains the speed of onset and differential block. The critical moments during spinal anesthesia come as soon as local anesthetic is injected into the subarachnoid space.

Official Title
-----------------
Measurement of Hemodynamic Variables Under Spinal Anesthesia in a Patient Undergoing Cesarean Section With Varied Positioning - a Comparative Study

Conditions
-----------------
Pregnancy, Anesthesia

Intervention / Treatment
-----------------
* Other: Supine position
* Other: Right lateral position
* Other: Left lateral position


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Parturients undergoing elective cesarean section under spinal anesthesia Singleton intrauterine pregnancy with appropriate gestational age fetus (AGA) at gestational age 37 to 42 weeks Exclusion Criteria: Large for gestational age, small for gestational age, and multiple gestations Patients with cardiovascular disease like hypertension, etc. Non-English or non-Spanish speakers BMI >40 Inadequate or failed blocks and inadvertently high levels of spinal blockade will be dropped from the study Incarcerated parturients Expected heavy bleeding (placenta accreta, vascular anomaly, etc.)

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
Female

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Sham Comparator: Supine position<br>Supine position Supine position after placement of spinal anesthetic | Other: Supine position<br>* Spinal anesthesia in sitting position then 2 minutes in Supine position after spinal anesthetic administration<br>|
| Active Comparator: Right lateral position<br>Right lateral position Right lateral after placement of spinal anesthetic | Other: Right lateral position<br>* Spinal anesthesia in sitting position then 2 minutes in the right lateral position after spinal anesthetic administration<br>|
| Active Comparator: Left lateral position<br>Left lateral position Left lateral after placement of spinal anesthetic | Other: Left lateral position<br>* Spinal anesthesia in sitting position then 2 minutes in the left lateral position after spinal anesthetic administration<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Heart rate | Continuous Heart rate (beats per minute) measurements. | Immediately before spinal anesthestic placement through placental delivery | 
| Blood pressure | Continuous Blood pressure (mmHg) measurements | Immediately before spinal anesthetic placement through placental delivery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of nausea and vomiting | Nausea and vomiting incidence and anti-emetic administration with time stamps will be documented. | Number of events spinal anesthetic placement through placental delivery | 
| Anti-emetic medication | Anti-emetic administration with time stamps will be documented. | Number of events spinal anesthetic placement through placental delivery | 
| Incidence of vasopressor usage | Number of vasopressor use events will be monitored and recorded. | Spinal anesthetic placement through placental delivery | 
| Total vasopressor usage | All vasopressor administrations with time stamps will be documented. | Spinal anesthetic placement through placental delivery | 
| Non Invasive Cardiovascular measurements: cardiac output | Continuous Cardiac output (L/min) measurements | Spinal anesthetic placement through placental delivery | 
| Non Invasive Cardiovascular measurements: stroke volume | Continuous Stroke volume (mL) measurements | Spinal anesthetic placement through placental delivery | 
| Non Invasive Cardiovascular measurements: TPR (total peripheral resistance) | Continuous TPR (total peripheral resistance, dynes*sec/cm3)measurements | Spinal anesthetic placement through placental delivery |