Hypotension during spinal anaesthesia for Caesarean section in a resource-limited setting: towards a consensus definition

Figures & data

Figure 1: Incidence of hypotension by absolute definition of SBP. Note: SBP =systolic blood pressure.

Figure 2: Incidence of hypotension by absolute definition of MAP. Note: MAP = mean arterial pressure.

Table 1: Incidence of hypotension using absolute blood pressure values

Absolute BP definition		Incidence	95% confidence interval
SBP	< 100 mmHg	49%	42.9–55.2
	< 90 mmHg	32.8%	27.3–38.9
	< 80 mmHg	15.8%	11.8–20.9
MAP	< 70 mmHg	60.5%	54.3–66.4
	< 65 mmHg	49.4%	43.3–55.6
	< 60 mmHg	34.4%	28.8–40.5

Note: SBP = systolic blood pressure, MAP = mean arterial pressure, BP = blood pressure.

Table 2: Incidence of hypotension using relative blood pressure values

BP definition relative to baseline		Incidence	95% confidence interval
SBP	< 30%	27.3%	22.1–33.1
	< 20%	49.0%	42.9–55.2
	< 10%	75.1%	69.4–80.1
MAP	< 30%	47.4%	41.3–53.6
	< 20%	75.5%	69.8–80.4
	< 10%	91.4%	87.1–94.2

Note: SBP = systolic blood pressure, MAP = mean arterial pressure, BP = blood pressure.

Table 3: Incidence of hypotension using composite definitions

Composite BP definition	Incidence of hypotension	95% confidence interval
< 30% MAP or < 80mmHg SBP	49.0%	42.9–55.2
< 20% MAP or < 90mmHg SBP	77.1%	71.5–81.9

Note: SBP = systolic blood pressure, MAP = mean arterial pressure, BP = blood pressure.

Table 4: Incidences of hypotension by time period

BP definition	Spinal to delivery	Delivery to 15 minutes post-delivery	Spinal to 15 minutes post-delivery
SBP < 100 mmHg	49.0% (42.9–55.2)	34.8% (29.1–40.9)	58.1% (51.9–64.1)
SBP < 20%	49.0% (42.9–55.2)	38.3% (32.5–44.5)	60.9% (54.7–66.7)
SBP < 100 mmHg or SBP < 20%	57.3% (51.1–63.3)	47.4% (41.3–53.6)	69.6% (63.6–75.0)

Note: Incidences reported as mean (confidence intervals). SBP = systolic blood pressure, MAP = mean arterial pressure, BP = blood pressure.