Vasopressors are a class of medication that constrict blood vessels and raise blood pressure, used to treat critically low blood pressure (hypotension) that cannot be corrected by fluid replacement alone. They work by stimulating receptors in blood vessel walls, causing them to narrow (vasoconstriction) and thereby increasing the resistance against which the heart pumps, which raises arterial pressure.
Vasopressors are an essential component of treatment in the critical care unit for conditions including cardiogenic shock, septic shock, and post-cardiac arrest haemodynamic instability. They are typically administered through a central venous catheter placed into a large vein, to ensure reliable delivery and to protect peripheral veins from the potent effects of these drugs.
Commonly used vasopressors include: noradrenaline (norepinephrine), the first-line vasopressor for most forms of shock, which primarily causes vasoconstriction with some increase in heart rate and contractility; adrenaline (epinephrine), used during cardiac arrest as part of the advanced life support algorithm and in refractory shock; vasopressin, an alternative or adjunct vasopressor used in septic shock and post-cardiac arrest care, acting through different receptors to noradrenaline; dopamine, used at higher doses for vasoconstriction but now less commonly used as first-line due to its side effect profile; and dobutamine, used primarily for its positive inotropic effect (increasing heart contractility) in cardiogenic shock, often alongside a vasopressor.
Titrating vasopressors requires continuous arterial blood pressure monitoring. The goal is to maintain adequate tissue perfusion, typically targeting a mean arterial pressure (MAP) of 65 mmHg or above in most shock states.
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