Effect of postural changes on inferior vena cava dimensions and its influence on haemodynamics during caesarean section under spinal anaesthesia

Abstract

The effect of postural changes on inferior vena cava (IVC) dimensions and its influence on intra-operative haemodynamics in term parturients can be studied using abdominal ultrasound by a subcostal approach. Thirty-two term parturients scheduled to undergo elective caesarean section under spinal anaesthesia were recruited in this observational study. End expiratory diameter and collapsibility index of IVC was measured preoperatively in 3 different positions - supine, recumbent with wedge and left lateral positions. End expiratory diameter was significantly high in recumbent (10.79) and left lateral (12.27) compared with supine (9.96) position (P < 0.0001). A greater fall in systolic blood pressure (>20%) was noted in patients with collapsibility index of more than 11.5 in recumbent with wedge position with a positive predictive value of 86%. IVC dimensions change significantly with change in position and collapsibility index in recumbent position can be a useful parameter for predicting hypotension during caesarean section under spinal anaesthesia.

Pregnant Women Positioning in Spinal Anesthesia for Cesarean Section: Integrative Review

“…The results of an observational study carried out in India with pregnant women submitted to spinal anesthesia for elective cesarean section corroborates with this fact. That study indicated arterial hypotension in 76% of pregnant women after spinal anesthesia and that the largest reductions, of 20% in systolic blood pressure, occurred between the sixth and seventh minutes after the anesthetic procedure [17].…”

Cardiac arrest despite optimal preloading of patient using ultrasonography-guided inferior vena cava indices under subarachnoid neuraxial blockade: A report of two cases

“…However, few studies exist which define their role in predicting fluid responsiveness under SA thereby limiting the hypotension. [ 5 6 7 ] In our first case, assessment of volume status and preloading was done under USG guidance. However, bradycardia followed by cardiac arrest occurred intraoperatively under subarachnoid block, which could be due to unopposed vagal response and handling of huge ovarian cyst which might have resulted in IVC occlusion leading to relative hypovolemia.…”

Assessment of venous hemodynamics and volume homeostasis during pregnancy: recommendations of the International Working Group on Maternal Hemodynamics

“…Limited data are available on the ultrasound assessment of inferior vena cava dimensions and collapsibility during inspiration and expiration in normal and complicated pregnancies. The diameter of the inferior vena cava changes significantly after intravenous volume load or changed maternal position in uncomplicated, term pregnancy. Compared with normal pregnancy, the vena cava collapsibility index, defined as ((Ø expiration – Ø inspiration)/Ø expiration) × 100% (where Ø is the diameter of the vena cava), is reduced in both late‐onset PE and PE with fetal growth restriction.…”