What is the treatment for hypotension?

Treatment of Hypotension

Hypotension treatment must be immediately directed at the underlying physiological cause—vasodilation, hypovolaemia, bradycardia, or low cardiac output—rather than empirically administering fluids, as only approximately 50% of hypotensive patients are fluid-responsive. 1

Algorithmic Approach to Treatment

Step 1: Identify the Underlying Cause

The most critical first step is determining which physiological derangement is causing hypotension, as treatment differs fundamentally based on etiology 1:

• Vasodilation: Treat with vasopressors
• Hypovolaemia: Treat with intravascular fluids (but only if fluid-responsive)
• Bradycardia: Treat with anticholinergics or chronotropes
• Low cardiac output: Treat with positive inotropes

Step 2: Assess Fluid Responsiveness (If Hypovolaemia Suspected)

Before administering fluids, perform a passive leg raise (PLR) test to determine if hypovolaemia is contributing to hypotension. 2, 3

• Positive PLR test (cardiac output increases): Indicates fluid responsiveness with positive likelihood ratio of 11 and pooled specificity of 92% 2, 3
• Negative PLR test (no cardiac output increase): Patient will likely not respond to fluid (negative likelihood ratio 0.13, pooled sensitivity 88%), requiring correction of vascular tone or inotropy instead 2

This is critical because in postoperative patients with suspected hypovolaemia, only 54% actually respond to fluid boluses 2, 3

Step 3: Cause-Directed Pharmacological Treatment

For Vasodilation:

• Norepinephrine is the first-line vasopressor 3, 4
• Add vasopressin if hypotension persists despite norepinephrine 3
• Phenylephrine is best reserved for hypotension with tachycardia (causes reflex bradycardia) 2, 3

For Hypovolaemia (if PLR positive):

• Administer intravascular fluids: crystalloid, colloid, or blood products 1
• Initial fluid bolus: 250-500 mL in adults, 10-20 mL/kg (maximum 1,000 mL) in children 2, 3
• Avoid additional fluid boluses in patients with cardiac dysfunction or volume overload signs (pulmonary edema) 2, 3

For Bradycardia:

• First-line: Atropine or glycopyrronium 1, 3
• If refractory: Epinephrine or isoprenaline 1
• Consider pacemaker for profound bradycardia 1

For Low Cardiac Output:

• Dobutamine or epinephrine for myocardial dysfunction 1, 3, 5
• Add norepinephrine if hypotension persists 3

Context-Specific Modifications

Trauma Without Brain Injury:

• Use restricted volume replacement strategy targeting systolic BP 80-90 mmHg (MAP 50-60 mmHg) until major bleeding is controlled 2, 3
• Aggressive fluid resuscitation increases mortality in this population 2, 3

Severe Traumatic Brain Injury:

• Maintain MAP ≥80 mmHg to ensure adequate cerebral perfusion 2, 3
• Do NOT use permissive hypotension 2, 3

Elevated Compartment Pressures:

• If compartment pressure is known or estimated (e.g., intraabdominal pressure 15 mmHg), increase MAP target by roughly the compartment pressure 1
• Example: If targeting organ perfusion pressure of 65 mmHg with compartment pressure of 15 mmHg, maintain MAP >80 mmHg 1

Orthostatic Hypotension (Chronic):

• First-line: Non-pharmacological measures including excluding exacerbating drugs, behavioral strategies, and increasing fluid/salt intake 3
• Midodrine is the first-line drug (Class I, Level A evidence), dosed individually up to 10 mg two to four times daily 3
• Fludrocortisone is another first-choice drug (Class IIa, Level B evidence), initially 0.05-0.1 mg daily, titrated to 0.1-0.3 mg daily 3
• Serial monitoring of serum electrolytes and renal function is mandatory with fludrocortisone 3

Monitoring Recommendations

• Continuous arterial pressure monitoring reduces severity and duration of hypotension compared to intermittent monitoring 1, 3
• Administer vasoactive agents targeted to effect rather than fixed doses 3
• Use intra-arterial monitoring for precise blood pressure targeting 3

Critical Pitfalls to Avoid

• Do NOT reflexively give fluids without assessing fluid responsiveness—approximately 50% of hypotensive patients are not hypovolemic 2, 3
• Avoid aggressive fluid resuscitation in trauma without brain injury—it increases mortality 2, 3
• Do NOT use permissive hypotension in traumatic brain injury—maintain MAP ≥80 mmHg 2, 3
• When treating intraoperative hypertension, use caution to avoid hypotension, as hypotension causes organ injury while reasonable levels of hypertension appear relatively benign 1
• Balance increasing standing blood pressure against avoiding marked supine hypertension when treating orthostatic hypotension 3