Can Right Toe Perfusion Index or Pleth Variability Index Predict Spinal Anesthesia Induced Hypotension?

Study Overview
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Brief Summary
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Spinal anesthesia for caesarean section is associated with a decrease in systemic vascular resistance and cardiac output and may cause hypotension in a significant portion of the parturients. Hypotension during delivery may cause maternal and fetal complications. If parturients who are likely to develop hypotension after spinal anesthesia can be identified before surgery, anesthesiologists would have opportunity to take measures such as prophylactic vasopressor administration. Perfusion index (PI) measured by pulse oximetry reflects vasomotor tone which affects the degree of hypotension after spinal anesthesia. This is a non-invasive method of assessing the relative vascular tone with the use of pulse oximeter which calculates the ratio of pulsatile versus the non-pulsatile component of the blood flow. A lower PI indicates greater peripheral vasomotor tone. Pleth variability index (PVI) is calculated using maximum and minimum values of perfusion index during respiratory cycles. PVI is one of the dynamic indices that can predict fluid responsiveness. There are several studies investigating the predictive value of finger PI and PVI on hypotension after spinal anesthesia. However the aortocaval compression by the gravid uterus directly effects the lower extremity perfusion. So, in this study we aimed to investigate whether the right toe PI and PVI values at supine and left lateral positions can predict hypotension during caesarean section.

Official Title
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Can we Predict Predict Spinal Anesthesia Induced Hypotension During Caesarean Section Using Right Toe Perfusion Index or Pleth Variability Index?

Conditions
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Cesarean Section Complications, Hypotension, Spinal Anesthesia, Perfusion Index, Pleth Variability Index

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: singleton parturient planned for elective LSCS under spinal anesthesia Exclusion Criteria: gestational age < 36 weeks emergency cases placenta previa, pre-eclampsia BMI>40 Reynauld disease patient refusal cardiovascular disease

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

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 |
| --- | --- |
| Hypotension group<br>Parturients undergoing elective C/S under spinal anesthesia whose systolic arterial pressure drop below 80 mmHg or have symptoms of hypotension such as dizziness, nausea and vomiting during the procedure. | |
| Non-hypotension group<br>Parturients undergoing elective C/S under spinal anesthesia whose systolic arterial pressure does not drop below 80 mmHg or have any symptoms of hypotension during the procedure. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| pleth variability index (PVI) | PVI values (%)at supine and lateral positions, before and after spinal anesthesia will be recorded and compared between the 2 groups. | perioperative | 
| Perfusion index (PI) | PI values(%)at supine and lateral positions, before and after spinal anesthesia will be recorded and compared between the 2 groups. | perioperative | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| blood pressure (mmHg) | blood pressure will be recorded | perioperative |