Detecting Hypotension By Continuous Non-invasive Arterial Pressure Monitoring

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

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 .

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.

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