From the Guidelines
Hypotension is typically defined as a systolic blood pressure less than 90 mmHg, as supported by the most recent and highest quality study 1. This definition is crucial in the context of perioperative care, where hypotension has been strongly associated with the development of organ injury 1. The condition can occur as a primary condition or as a symptom of various underlying health issues, and its treatment depends on the underlying cause. Common symptoms of hypotension include dizziness, lightheadedness, blurred vision, fatigue, nausea, and in severe cases, fainting or loss of consciousness. Causes of hypotension include dehydration, blood loss, heart problems, endocrine disorders, severe infections, certain medications, and neurological disorders. Some key points to consider in the management of hypotension include:
- Monitoring arterial blood pressure remains a critical aspect of perioperative practice 1
- The capture of patient-specific risks combined with physiological measurements has identified that lower-than-normal arterial blood pressure measured during and after surgery is associated with poorer postoperative outcomes 1
- Treatments for hypotension that are mechanistically rational require a clinically plausible threshold or indication, as well as a solid evidence-based outcome that confers benefit to the patient 1
- The frequently brief and treated occurrence of hypotension, unless extreme and prolonged, may be a biomarker for injurious pathophysiological substrate(s) underpinning dysregulated blood pressure control 1. It is essential to evaluate symptomatic hypotension by a healthcare provider, as chronic hypotension without symptoms often does not require treatment. In the context of real-life clinical medicine, prioritizing the single most recent and highest quality study 1 is crucial in making a definitive recommendation regarding the definition and management of hypotension.
From the Research
Definition of Hypotension
The definition of hypotension, also known as low blood pressure, can vary depending on the context and population being studied.
- According to 2, the optimal definition of hypotension differs by age group, with systolic blood pressure cutoff values of 85 mm Hg for patients aged 18 to 35 years, 96 mm Hg for patients aged 36 to 64 years, and 117 mm Hg for elderly patients.
- Another study 3 found that the optimal definition of hypotension was systolic blood pressure of 100 mm Hg for patients 20 to 49 years, 120 mm Hg for patients 50 to 69 years, and 140 mm Hg for patients 70 years and older.
- In the context of severe head injury, hypotension is defined as a single observation of a systolic blood pressure of <90/mm Hg 4.
- Orthostatic hypotension, a specific type of hypotension, is defined as a drop in systolic blood pressure of at least 20mmHg or a drop in diastolic blood pressure of at least 10mmHg within 3minutes of standing 5, 6.
Key Findings
- The definition of hypotension can vary depending on the age group and context.
- Different studies have proposed different cutoff values for systolic blood pressure to define hypotension.
- Orthostatic hypotension is a common disorder, especially in high-risk populations such as elderly subjects and patients with neurological diseases.
- Treatment of hypotension generally aims to address the underlying cause and may involve pharmacologic or nonpharmacologic interventions.