Physical exam findings to suggest high ventricular filling pressures
Diffuse or dependent crackles and JVD suggest high filling pressures unless ARDS or diffuse pneumonia is present
PE findings to suggest low ventricular filling pressures
Clear lung fields and flat neck veins in the setting of hypotension
Risks of overly aggressive fluid resuscitation
Pulmonary edema, ileus or bowel edema and compartment syndromes
Ways to avoid giving too much fluid
Frequent chest auscultation, PaO2 and CVP monitoring
When should you consider IAP monitoring?
In patients requiring massive fluid resuscitation
Vasopressor
A medication that has alpha-1 adrenergic activity leading to arteriole constriction, rise in SVR and arterial BP
Inotrope
Medication that augments cardiac contractility and HR through beta-1 adrenergic effects
Beta-1-adrenergic receptor
Increases cardiac contractility and/or HR
Beta-2-adrenergic receptor
Mediates bronchodilation and arteriole dilation
Alpha-1-adrenergic receptor
Mediates arteriole constriction and increases PVR
Norepinephrine (levophed)
- 0.01-0.5 ug/kg/min
- DOC in septic shock.
- Potent alpha-1 vasoconstrictor
- Also has beta-1 inotropic and chronotropic effects
- Usually increases renal blood flow in patients
Dopamine
- 1-20 ug/kg/min
- 1-5 ug/kg/min acts on dopamine receptor and increases urine output. No benefit to this.
- 6-10 ug/kg/min acts primarily on beta-1 receptors to increase the HR
- > 10 ug/kg/min has significant alpha-1 effects to cause vasoconstriction
- Potential AEs = arrhythmias and tachycardia
Epinephrine
- 0.01-0.5 ug/kg/min
- Potent alpha-1, beta-1 and beta-2 effects
- Increases myocardial O2 consumption
- Do not use in patient with CAD
Phenylephrine (Neo-Synephrine)
- 1-300 ug/min (start at 25 ug/min
- Pure alpha-1 vasoconstrictor (arterial only!)
- Best in neurogenic shock or hypotension caused by an epidural catheter
Vasopressin
- Vasopressor that acts on V1 receptors to cause vasoconstriction
- Higher doses may lead to ischemic events
- May be used in hypotensive shock that is refractory to other agents but no improvement in mortality
Dobutamine
- 1-20 ug/kg/min
- Acts on non-selective B adrenergic agonists
- Has inotropic effects leading to increased CO from increased stroke volume
- Use with caution because it can cause a drop in BP if hydration status inadequate
Milrinone
- Phosphodiesterase inhibitor with indirect beta-1 and beta-2 effects
- Inhibits breakdown of cyclic AMP, the second messenger for catecholamines.
- Increases CO by increasing stroke volume
- Decreases after load by causing arteriole dilation
- Use with caution in hypovolemic patients!
