Clinical Trial: Comparative Study of Haemodynamic Changes After Spinal Anaesthesia in Non-obese and Pregnant Women

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Comparative Study of Haemodynamic Changes After Spinal Anaesthesia in Non-obese and Pregnant Women

Brief Summary: Obesity has become one of the most common risk factors in obstetric practice with serious anaesthetic implications. Obese pregnants have limited physiological reserves and cardiovascular co- morbidities when compared to non-obese pregnant women. Spinal anaesthesia is the anaesthetic technique of choice for caesarean section. The haemodynamic changes associated with spinal anaesthesia pose the greatest hazard to the mother and the foetus and are exaggerated in obese pregnant women. However differences in the changes in haemodynamic variables such as cardiac output (CO), stroke volume (SV) and systemic vascular resistance (SVR) between obese and non-obese pregnant women having caesarean section (CS) under spinal anaesthesia have not been studied before. This study compares the haemodynamic changes after spinal anaesthesia for CS in non-obese and obese parturients in a single centre, prospective case control study, using LiDCOrapidV2. This LiDCOrapidV2 device is a noninvasive method of measuring haemodynamic variables. It is a single centre, prospective, case control study. The primary outcome compares the differences and variability in CO, SV and SVR between obese and non-obese parturients. The secondary outcomes include comparison of the correlation between changes in blood pressure (BP) and CO in each patient and the difference in BP between conventional intermittent oscillometric device and continuous LiDCORapidV2in each patient with a view to assess the need for measurement of cardiac output in obstetric anaesthesia

Detailed Summary:

Pregnancy is a state of physiological alteration as a result of increased oxygen demand and involves significant haemodynamic changes including sustained rises in cardiac output (CO) (by up to 30- 60%) and stroke volume (SV) (up to 30%) by virtue of increase in the blood volume This is associated with decrease in the systemic vascular resistance (SVR) and enhanced myocardial performance. When pregnancy is associated with obesity the cardiovascular system is further stressed. Obese pregnant women with a body mass index (BMI) more than 35kg/m2 pose significant health issue and are at risk for anaesthesia related maternal mortality. Several cases of sudden cardiac arrests of unexplained cause in obese pregnants have been reported. Obesity induced pathological changes have profound effects on cardiac endothelial and vascular function. Thus in pregnancy, obesity leads to further increase in blood volume and cardiac output proportionate to the amount of fat thus causing further volume overload of the heart. A study conducted with transthoracic echo showed a mean increase of around 550mls in cardiac output between obese and non-obese parturients in the third trimester. In contrast to the decrease in SVR that occurs in normal pregnancy, obesity by itself is associated with increased SVR by virtue of the increased sympathetic activity due to the effects of hormones including leptin, insulin and inflammatory mediators. This causes an increase in afterload 6, 8 thus offsetting the advantage of reduced afterload of normal pregnancy affecting the CO further. This combination of volume and pressure overload leads to systolic dysfunction. Furthermore the increase in heart rate of pregnancy in line with elevated cardiac output will decrease the diastolic interval and time for myocardial perfusion causing diastolic dysfunction. Thus obese pregnant patients may present with a systolic, diastolic or both systolic and diastolic dysfunction
Sponsor: University of Aberdeen

Current Primary Outcome: Difference in the variation of cardiac output (CO) from baseline values between obese and non-obese parturients after spinal anaesthesia. [ Time Frame: 18 months ]

Original Primary Outcome:

• Difference in the variation of cardiac output (CO) from baseline values between obese and non-obese parturients after spinal anaesthesia. [ Time Frame: 18 months ]
  The change in cardiac output from baseline measured as millitres/minute at predetemined intervals after spinal anaesthesia will be recorded in each group. The mean value of this change in each group will be compared for each recording and the difference in the change between the two groups will be reported.
• Difference in the variation of Stroke Volume (SV) from baseline values between obese and non-obese parturients after spinal anaesthesia. [ Time Frame: 18 months ]
  The change in Stroke Volume (SV) from baseline measured as millitres at predetemined intervals after spinal anaesthesia will be recorded in each group. The mean value of this change in each group will be compared for each recording and the difference in the change between the two groups will be reported.
• Difference in the variation of systemic vascular resistance(SVR) from baseline between obese and non-obese parturients after spinal anaesthesia at frequent intervals. [ Time Frame: 18 months ]
  The change in SVR from baseline measured as dynes x s/cm5 at predetemined intervals after spinal anaesthesia will be recorded in each group. The mean value of this change in each group will be compared for each recording and the difference in the change between the two groups will be reported.

Current Secondary Outcome: Mean difference in the amount of vasopressors infused in millilitres/hour between non-obese and obese pregnant women. [ Time Frame: 12 months ]

Original Secondary Outcome: Same as current

Information By: University of Aberdeen

Dates:
Date Received: December 15, 2014
Date Started: December 2014
Date Completion:
Last Updated: September 7, 2016
Last Verified: September 2016