Thank you Matt H for your help with these PEARLS!!!
Thanks to Chloe for presenting a fascinating case of a 65 year old man with history of HOCM (w/o obstruction) who presented with acute onset shortness of breath, ultimately thought secondary to flash pulmonary edema from paroxysmal hypertension. We had a great discussion on vasopressors to use in different types of shock. Below is a summary of some of the more common vasopressors, as well as brief information on key considerations in their use. Finally, there is a bit of info on the ESCAPE trial that led to reductions in use of PA catheters in management of cardiogenic shock.
For more information, refer to the UCSF Hospitalist Handbook and the MGH CCU handbook.
- Dobutamine is considered a first line pressor in cardiogenic shock b/c it improves contractility and drops SVR (watch out for dropping BPs).
- HOWEVER, never write for a MAP goal and titration parameters when using dobutamine as patients MAPs will sometimes drop with up titration (this is why we sometimes start this with norepinephrine).
- The ESCAPE (2005) showed no improved 6 month mortality in patient with decompensated heart failure randomized to management with PA catheter monitoring vs. usual care. See indications for when to us a PA catheter below.
||α-1, β-1 agonist
||α-1, β-1, β-2 agonist
β-1, β-2 agonist
||β-1 > β-2 agonist
||PDE III inhibitor
||Splancnic vasodilation – increases renal blood flow
Quick info on selected vasoactive agents:
Norepinephrine: 1st line pressor for sepsis, cardiogenic shock, undifferentiated shock.
Vasopressin: Often 2nd line pressor in sepsis. Use caution in patients with coronary or peripheral vascular ischemia. Not affected by acidosis (many other pressors are less effective in this situation)
Phenylephrine: Useful for pure vasodilatory hypotension (e.g. sedation-related hypotension). Generally avoid in cardiac patients as can cause reflex bradycardia with decreased cardiac output. HOWEVER, can be useful in unstable arrhythmias when beta agonism may be undesirable. Also useful in HOCM with dynamic outflow obstruction (‘stents’ open the obstruction) or fixed obstruction in AS as it increases SVR without changing afterload felt by the heart.
Epinephrine: Primary use is in ACLS, though can also be used as 3rd pressor in refractory hypotension. Adverse effects include tachycardia/tacchyarrythmias, peripheral vasoconstriction and end-organ damage
Dobutamine: Increases contractility while reducing SVR. Often decreases blood pressure, therefore should not be thought of as a vasopressor, should also not be titrated to MAP goals. Risk of arrhythmia with higher doses, also risk of myocardial ischemia from increased oxygen demand.
Milrinone: PDE-3 inhibitor, inhibits cAMP breakdown. Similar to dobutamine, results in both inotropy and decreased SVR (perhaps more reduction in afterload, but also more risk of hypotension, than dobutamine). Requires dose-reduction in renal impairment.
Indications for PA Catheters
ESCAPE trial (2005) – randomized patients with acute decompensated heart failure to therapy guided by PA catheter vs no PA catheter. No difference in 6 month mortality or days out of the hospital. Based on this trial and meta-analysis, PA catheters are no longer used routinely. They still have a role in shock of uncertain etiology or when initial management is unsuccessful.
AHA guidelines on PA catheters (2013):
- Recommended in patients with respiratory distress or evidence of impaired perfusion when intracardiac filling pressures can’t be determined by clinical assessment (class I, level C)
- Can be useful in heart failure with persistent symptoms despite standard therapy if any of the following are present: (class IIa, level C):
- Uncertain volume status, perfusion, SVR, PVR
- Persistent hypotension
- Worsening renal function despite initial therapy
- Need for vasoactive agents
- Anticipated need for mechanical cardiac support
- Routine use not recommended in normotensive patients with acute decompensated heart failure responding to diuresis and afterload reduction (class III, level B)