KUMJ | VOL. 19 | NO. 1 | ISSUE 73 | JAN.-MARCH, 2021
Thresholds for Spinal Anaesthesia-induced Hypotension During Caesarean Section
Gautam B, Bhattarai A
Abstract: Background
Spinal anaesthesia is the current standard for caesarean section. Hypotension, a
common complication, potentially results in adverse foetal and maternal outcomes.
However, hypotension-defining criteria are varied.
Objective
To identify the blood pressure thresholds for spinal anaesthesia-induced hypotension
during caesarean section.
Method
This is a retrospective cohort study of spinal anaesthesia-induced hypotension that
occurred till baby-delivery during caesarean section. Reports on intraoperative
hypotension, collected previously from January to December 2019, were reviewed
to identify the hypotension-defining thresholds. The thresholds were categorized
into systolic blood pressure (SBP) of 80, 90 or 100 mmHg, mean arterial pressure
(MAP) of 60, 65 or 70 mmHg, combinations, and others. Parturient and anaesthesia
characteristics, and associated hypotensive symptoms were also recorded for
descriptive analysis.
Result
Spinal anaesthesia-induced hypotension was identified in 129 (11.5%) cases among
1116 caesarean sections. Altogether, 12 hypotension-defining thresholds were
employed. Thresholds of SBP 90, MAP 60, and SBP 80 mmHg were used in 53 (41%),
28 (21.7%), and 21 (16.2%) cases respectively. Mean maternal age was 28 (±4.22)
years and 87 (67.4%) cases underwent emergency surgery. Median sensory blockade
level was T4. Nausea-vomiting, bradycardia, and tachycardia were associated during
five (3.8%), six (4.6%), and 15 (11.6%) hypotensive incidents respectively. Two cases
had unrecordable blood pressure but there was no maternal mortality.
Conclusion
Systolic blood pressure of 90 mmHg and mean arterial pressure of 60 mmHg included
the most common thresholds for spinal anaesthesia-induced hypotension during
caesarean section. Identifying the safe and clinically relevant hypotension-defining
criteria needs further investigation.
Keyword : Caesarean section, Criteria, Definition, Hypotension, Spinal anaesthesia, Threshold
