Perfusion Index and Hypotension During Spinal
Anaesthesia for Caesarian Section L Hammon, I Wrench, S Handa*, R Mahajan*
Anaesthetic Department, Sheffield Teaching Hospitals NHS Foundation Trust, *Anaesthetic Department, Nottingham University Hospitals NHS Foundation Trust
Hypotension is common with spinal anaesthesia (SA) Caused by sympathetic block.1 Intermittent non-invasive blood pressure measurement (NIBPM) is standard
-may fail to detect episodes of hypotension in a timely fashion compared to a continuous NIBPM device.2
Previous work suggests a perfusion index (PI) of >3.5 predicts likelihood of hypotension during SA.3 No studies to guide early management of hypotension.
GOAL: Observational study to establish if PI (and pleth variability index (PVI*) could help prevent significant hypotension.
*variability of PI with respiratory cycle
19 patients for elective LSCS. Radical Seven® pulse oximeter (measures PI and PVI) and finometer (continuous NIBPM) attached prior to SA.
Following initiation of SA, PI values rose in 15 cases (and PVI fell in 13 cases)." On average PI values rose more rapidly for the ten patients who experienced hypotension (fall in systolic BP>25%) " Eight patients (no value for one) who did not become hypotensive had initial PI readings of <3.5
-Only three out of the ten who did become hypotensive had initial PI values of <3.5 (sensitivity 70%, specificity 100%).
Timing and degree of change in PI and PVI varied widely between patients. It did not demonstrate potential to inform management of blood pressure. High PI pre-SA may predict the occurrence of hypotension. PI appeared to increase higher and more quickly in women with significant hypotension
-suggests SA may have developed more quickly in these cases.