What is Considered a Viable Blood Pressure?
A viable blood pressure is generally defined as a systolic blood pressure of at least 90 mmHg in adults, which is sufficient to maintain adequate perfusion to vital organs. 1, 2
Normal and Abnormal Blood Pressure Categories
Blood pressure is categorized into several ranges:
- Normal blood pressure: <120/80 mmHg
- Elevated blood pressure: 120-139/70-89 mmHg
- Stage 1 hypertension: 130-139/80-89 mmHg
- Stage 2 hypertension: ≥140/90 mmHg 2, 1
Minimum Viable Blood Pressure
The minimum viable blood pressure varies based on clinical context:
- For hemodynamic stability in trauma patients: Systolic blood pressure ≥90 mmHg in adults 1
- For trauma patients without brain injury: Target systolic blood pressure of 80-90 mmHg until major bleeding has stopped 1
- For trauma patients with brain injury: Mean arterial pressure ≥80 mmHg should be maintained 1
- For patients in shock: Systolic blood pressure of 80-100 mmHg is considered sufficient to maintain circulation to vital organs 3
Important Considerations
Research shows that trauma patients with systolic blood pressure of 90-109 mmHg have significantly higher mortality (5% vs 1%) and infection rates (39% vs 22%) compared to those with SBP ≥110 mmHg 4. This suggests that even "borderline" blood pressures that were traditionally considered adequate may actually be associated with worse outcomes.
Target Blood Pressure for Different Populations
Different clinical scenarios require different blood pressure targets:
- General adult population on treatment: Target systolic BP of 120-129 mmHg 1, 2
- Elderly patients (≥65 years): Target systolic BP <130 mmHg if tolerated 2
- Very elderly patients (>80 years): Target systolic BP of 140-145 mmHg if well tolerated 2
- Patients with heart failure: Consider target BP <120/80 mmHg 2
- Patients in acute hypotensive states: Maintain systolic BP between 80-100 mmHg 3
Diastolic Blood Pressure Considerations
- Diastolic blood pressure should generally be maintained above 60 mmHg to preserve coronary perfusion 2
- For patients on treatment, a target diastolic BP of 70-79 mmHg is recommended 2
Pitfalls and Caveats
Avoid excessive hypotension: Research suggests that a blood pressure of 115/75 mmHg is associated with minimal vascular mortality 5, but in acute settings, maintaining adequate organ perfusion takes priority.
Consider patient-specific factors: Age, comorbidities, and clinical context significantly impact what constitutes a "viable" blood pressure.
Beware of "borderline normal" blood pressure in trauma: Patients with SBP 90-109 mmHg should be considered at risk and may require aggressive resuscitation 4.
Monitor for orthostatic hypotension: This is particularly important in elderly patients and those on multiple antihypertensive medications 2.
Recognize that systolic and diastolic components have different significance: Systolic blood pressure has emerged as a better predictor of cardiovascular risk than diastolic pressure 6.
In emergency settings, the goal is to maintain adequate tissue perfusion rather than achieving specific blood pressure numbers. For patients in shock or with acute hemorrhage, a systolic blood pressure of 80-100 mmHg may be temporarily acceptable until definitive treatment can be provided 3.