Study of correlation of anthropometric measurements and spread of spinal anaesthesia in parturiants undergoing caesarean section – A Prospective Observational Study

Spinal anesthesia is widely used in parturients for cesarean section.Plain bupivacaine is often used for spinal anesthesia. However, the intrathecal spread of plain bupivacaine is highly unpredictable.Patient characteristics such as height, weight, and body mass index are frequently used to predict spinal anesthesia spread, but the results have been unsatisfactory.Certain anthropometric measurements that are practically obtainable may explain the variability in the spread of spinal anesthesia to some extent.These can be useful to clinicians for quick assessment of the spread of sensory level of spinal anesthesia in individual patients to avoid the risk of high block and also an inadequate level of block. All of the term parturients will be kept nil per oral for 8 h before the cesarean section.Parturient will be placed on a horizontal operating table in the supine position, and during the end of expiration, the abdominal girth will be measured at the level of the umbilicus. While the parturient is sitting on the operating table with a straightened back  ,VCL will be measured from the middle of the C7 vertebra to the sacral hiatus and hip‑width is measured between the two iliac crests, shoulder‑width is measured between two acromion processes.

A total of 2mL of 0.5% plain bupivacaine is injected intrathecally over a period of 10 seconds when free flow of CSF is obtained. After the spinal injection, the patients will be immediately returned to the supine position.

The spinal spread will be assessed in  midclavicular line every 2 minutes using a 23-gauge needle for loss of pinprick sensation , continued till there will be  no further increase in three consecutive observations. Time to achieve the maximum sensory level will be defined as the time between the intrathecal injection and loss of pinprick sensation to that level.

Correlation and linear regression analysis will be used to analyse whether any relation exists between the highest level of sensory blockade achieved and the parturients’ VCL, Shoulder/hip width and abdominal circumference.