Vasopressors are a powerful class of drugs that induce vasoconstriction and thereby elevate mean arterial pressure. Vasopressors differ from inotropes, which increase cardiac contractility. However, many drugs have both vasopressor and inotropic effects.
Peripheral vasopressor use is a safe, temporising measure for patient stabilisation. It should only be performed as a temporising measure until central venous access is obtained.
Indications
Hypotension may result from:
- hypovolemia, e.g. exsanguination, or
- pump failure, e.g. severe medically refractory heart failure or shock complicating myocardial infarction, or
- a pathologic maldistribution of blood flow, e.g. septic shock, anaphylaxis.
Vasopressors are indicated for a decrease of >30 mmHg from baseline systolic blood pressure, or a mean arterial pressure <60 mmHg when either condition results in clinical signs of end-organ dysfunction due to hypoperfusion.
Hypovolemia should be corrected before starting vasopressor therapy (see shock).
Key principles of critical care pharmacotherapy
Medication and line management
Selection of the first line agent is dependent on the underlying cause of the shock.
Start infusions with low doses and titrate carefully.
- Titration should aim to achieve effective end organ perfusion as evidenced by urine output or mentation.
- Aim for mean arterial pressure (MAP) ≥65 mmHg and urine output ≥0.5 mL/kg/h.
Use peripheral vasopressor infusions for up to 6 hours.
- Prioritise placement of central venous catheter (CVC) if hypotension is refractory to vasopressors (greater than one vasopressor required or rapidly increasing requirements).
- Clearly mark vasopressors line and ensure lines are securely attached.
- Ensure you are not bolusing or pushing medications in the same line.
- Ensure you have sufficient infusion volume available and draw up additional syringes ahead of time.
Monitoring and assessment
Regularly assess patient’s haemodynamic status and ongoing requirement for vasopressors.
- Continually monitor patient’s condition ensuring appropriate alarm settings (ECG, blood pressure, respiratory rate, SpO2 at minimum, ideally invasive haemodynamic monitoring when able).
- Vasopressor therapy can result in dysrhythmias, hyperglycaemia, peripheral extravasation and hypoperfusion of extremities, mesentery and kidneys.
Make the intravenous cannula access visible. Rigorous clinical monitoring for signs of extravasation and prompt management is essential.
Accessed from the Emergency Care Institute website at https://aci.health.nsw.gov.au/networks/eci/clinical/tools/vasopressors