Detecting Hypotension By Continuous Non-invasive Arterial Pressure Monitoring

Study Overview
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Brief Summary
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The purpose of this study is to determine whether continuous non-invasive arterial pressure (CNAP) monitoring is beneficial to maintain maternal hemodynamic stability and improve the outcomes of maternal and fetal comparing with intermittent oscillometric non-invasive arterial pressure (NIAP)measurement during spinal anaesthesia for cesarean section .

Detailed Description
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Peri-operative hypotension and fluctuation of arterial blood pressure (BP) during spinal anaesthesia are common. Hypotension causes maternal side-effects such as unconsciousness, dizziness, nausea, and vomiting. The potential fetal side-effects are caused by a reduction in the uterine blood flow with consequent reduced oxygen supply and acidosis reflected by impaired blood gas analyses and impaired Apgar scores. Because of the potential harm to the fetus and the dependency of fetal oxygenation on maternal arterial pressure (AP), it has been strongly recommended to closely monitor mother's arterial pressure and to treat hypotension immediately. Non-invasive arterial pressure (NIAP) measurement is a common method for monitoring in clinical. These hypotension episodes probably would be detected with delay by NIAP measurement on account of its discontinuous. A monitor for continuous non-invasive arterial pressure monitoring (CNAPTM Monitor 500, CNSystems Medizintechnik AG,Graz, Austria) using the volume-clamped method. It can monitor timely and provide beat-to-beat value of arterial pressure. The purpose of this study is to determine whether continuous non-invasive arterial pressure (CNAP) monitoring is beneficial to maintain maternal hemodynamic stability and improve the outcomes of maternal and fetal.

Official Title
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Detecting Hypotension By Continuous Non-invasive Arterial Pressure Monitoring During Spinal Anaesthesia for Cesarean Section:A Prospective,Randomized, Controlled Study

Conditions
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Hypotension

Intervention / Treatment
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* Drug: phenylephrine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: scheduled for elective caesarean section with spinal anaesthesia pregnancy week above 36 Exclusion Criteria: age<18 yr cardiac arrhythmia vascular pathologies of the upper limbs (recent vascular surgery, Raynaud's disease， vascular stenosis) contraindication for spinal anaesthesia emergency case

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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Design Details

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


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Group C<br>Arterial pressure of the patients in Group C is measured by continuous non-invasive arterial pressure (CNAP).When systolic blood pressure decreased by over 20% of the basic value or systolic blood pressure lower than 100mmHg after spinal anaesthesia,phenylephrine was administered 50ug .If systolic blood pressure did not improve after 1 minute,phenylephrine was administered repeatedly until systolic blood pressure return to normal. | Drug: phenylephrine<br>* When systolic blood pressure decreased by over 20% of the basic value or systolic blood pressure lower than 100mmHg after spinal anaesthesia,phenylephrine was administered 50ug in Group C and Group N.If systolic blood pressure did not improve after 1 minute,phenylephrine was administered repeatedly until systolic blood pressure return to normal.<br>* Other names: Phenylephrine Hydrochloride;|
| Experimental: Group N<br>Arterial pressure of the patients in Group N is measured by intermittent oscillometric non-invasive arterial pressure (NIAP).When systolic blood pressure decreased by over 20% of the basic value or systolic blood pressure lower than 100mmHg after spinal anaesthesia,phenylephrine was administered 50ug .If systolic blood pressure did not improve after 1 minute,phenylephrine was administered repeatedly until systolic blood pressure return to normal. | Drug: phenylephrine<br>* When systolic blood pressure decreased by over 20% of the basic value or systolic blood pressure lower than 100mmHg after spinal anaesthesia,phenylephrine was administered 50ug in Group C and Group N.If systolic blood pressure did not improve after 1 minute,phenylephrine was administered repeatedly until systolic blood pressure return to normal.<br>* Other names: Phenylephrine Hydrochloride;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| the maximum change of systolic blood pressure(SBP),assessed using continuous non-invasive arterial pressure device or intermittent oscillometric arterial pressure measurement | (baseline SBP-minimum SBP)/baseline SBP | between the spinal anesthetic injection and the delivery of the fetus and placenta,assessed up to 30 mins | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Detecting the occurrence of hypotension | systolic blood pressure decreased by over 20% of the baseline or systolic blood pressure lower than 100mmHg | between the spinal anesthetic injection and the delivery of the fetus and placenta,assessed up to 30 mins | 
| Neonatal outcome was assessed with Apgar scores |  | between the spinal anesthetic injection and the delivery of the fetus and placenta,assessed up to 30 mins | 
| umbilical cord blood gases analysis at birth |  | between the spinal anesthetic injection and the delivery of the fetus and placenta,assessed up to 30 mins | 
| the incidence of nausea and vomiting on account of hypotension | The presence of nausea and vomiting was measured on a 3-point scale of 1,2, and 3 indicating no nausea and no vomiting, nausea only, and both nausea and vomiting, respectively. Assessments were done at 1-minute intervals after the spinal injection until 25 min. | between the spinal anesthetic injection and the delivery of the fetus and placenta,assessed up to 30 mins | 
| the incidence of dizziness on account of hypotension | assessment:yes=patient had dizziness,no=patient had no dizziness | between the spinal anesthetic injection and the delivery of the fetus and placenta,assessed up to 30 mins | 
| the incidence of dyspnea on account of hypotension | assessment:yes=patient had dyspnea,no=patient had no dyspnea | between the spinal anesthetic injection and the delivery of the fetus and placenta,assessed up to 30 mins | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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obstetric, anesthesia, hypotension, arterial pressure, measurement techniques