Treatment Options for Hypotension
The treatment of hypotension should be based on the presumed underlying causes including vasodilation, hypovolaemia, bradycardia, and low cardiac output. 1
Initial Assessment and Management
- Perform a bedside assessment to define the cause of hypotension before initiating treatment 1
- Consider a passive leg raise (PLR) test to assess fluid responsiveness - a positive test (increased cardiac output) strongly predicts fluid responsiveness with 92% specificity and 88% sensitivity 1
- For patients with a positive PLR test, intravenous fluid administration is appropriate, as approximately 50% of hypotensive patients are fluid responsive 1
- For patients with a negative PLR test, focus on vascular tone and chronotropy/inotropy as the primary treatment strategy 1
Treatment Based on Underlying Cause
Vasodilation
- Vasodilation can be reversed by vasopressors such as phenylephrine or norepinephrine 1
- Norepinephrine is indicated for blood pressure control in acute hypotensive states and as an adjunct in profound hypotension 2
- Administer norepinephrine in dextrose-containing solutions (5% dextrose or 5% dextrose with sodium chloride) to prevent oxidation and potency loss 2
- Initial dosing: 8-12 mcg/min, then adjust to maintain blood pressure (average maintenance dose: 2-4 mcg/min) 2
Hypovolaemia
- Treat with intravascular fluid administration using crystalloid solutions (preferably lactated Ringer's) 1
- In previously hypertensive patients, aim to maintain blood pressure no higher than 40 mmHg below the preexisting systolic pressure 2
- Continue fluid therapy until adequate blood pressure and tissue perfusion are maintained 2
Bradycardia
- Administer anticholinergic agents such as atropine or glycopyrronium 1
- For bradycardia unresponsive to anticholinergics, consider epinephrine or isoprenaline 1
- For profound bradycardia, a pacemaker may be necessary 1
Low Cardiac Output
- Treat with positive inotropic agents such as dobutamine or epinephrine 1
- Consider dobutamine (2.5-10 μg/kg/min) if there is evidence of low cardiac output in cardiogenic shock 3
Special Considerations
Orthostatic Hypotension
- For orthostatic hypotension, consider volume expansion through salt supplements, an exercise program, or head-up tilt sleeping (>10°) 1
- Midodrine is indicated for symptomatic orthostatic hypotension in patients whose lives are considerably impaired despite standard clinical care 4
- Discontinue or reduce hypotensive drugs that may be contributing to orthostatic hypotension 1
Cardiogenic Shock
- Rapidly evaluate volume status and administer norepinephrine to maintain mean arterial pressure ≥65 mmHg 3
- Perform echocardiographic assessment to determine etiology and guide definitive treatment 3
- Consider dobutamine for low cardiac output in ventricular dysfunction 3
Situational Syncope
- Identify and avoid trigger events when possible 1
- Maintain central volume and use protected posture (e.g., sitting rather than standing) 1
Monitoring and Adjustments
- Continuously monitor ECG, blood pressure, oxygen saturation, and urine output 3
- Assess arterial blood gases and serum lactate as markers of tissue perfusion 3
- Reduce vasopressor therapy gradually to avoid abrupt withdrawal 2
- Monitor for signs of tissue necrosis with peripheral administration of vasopressors; central line administration is preferred 3
Pitfalls and Caveats
- The typical approach of correcting postoperative hypotension with intravenous fluid may be inappropriate in approximately 50% of cases 1
- Phenylephrine is best used when hypotension is accompanied by tachycardia, as it can cause reflex bradycardia 1
- Avoid excessive fluid administration in non-fluid responsive patients, as this may lead to fluid overload and complications 1
- When treating hypertension, use caution to avoid overcorrection leading to hypotension, which can cause organ injury 1
- Always correct blood volume depletion before administering vasopressors when possible 2