Undifferentiated shock
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Undifferentiated Hypotension Algorithm
Check/manage the following in order:
- Pulse (assess based on pt's age)
- Too slow or too fast (to the point where CO is affected)?
- If so, HR is likely primary etiology of hypotension
- Pace or cardiovert
- Too slow or too fast (to the point where CO is affected)?
- Volume Status
- What is the LV end-diastolic volume?
- Approximated by the IVC diameter or CVP
- If low:
- What is the LV end-diastolic volume?
- Contractility
- Is the myocardium severely depressed in its contractile function (cardiogenic shock)?
- Assess via ultrasound
- Treat w/ inotrope
- Is forward flow occurring?
- Assess for valvular dysfunction (MR, AR)
- Assess for obstruction (PE, tamponade)
- Is the myocardium severely depressed in its contractile function (cardiogenic shock)?
- Systemic Vascular Resistance
- Pathologic vasodilation (decreased SVR) suggested by:
- Warm extremities
- Bounding pulse
- Treated based on likely etiology of distributive shock (see below)
- Pathologic vasodilation (decreased SVR) suggested by:
Differential Diagnosis
Shock
- Cardiogenic
- Acute valvular Regurgitation/VSD
- CHF
- Dysrhythmia
- ACS
- Myocardial Contusion
- Myocarditis
- Drug toxicity (e.g. beta blocker, CCB, or bupropion OD)
- Obstructive
- Distributive
- Hypovolemic
- Severe dehydration
- Hemorrhagic shock (traumatic and non-traumatic)
Management
- Treat underlying type
Vasopressors
Pressor | Initial Dose | Max Dose | Cardiac Effect | BP Effect | Arrhythmias | Special Notes |
---|---|---|---|---|---|---|
Dobutamine | 3-5 mcg/kg/min | 5-15 mcg/kg/min (as high as 200) [1] | Strong ß1 agonist +inotrope +chronotrope, Weak ß2 agonist +weak vasodilatation ) | alpha effect minimal | HR variable effects. | indicated in decompensated systolic HF, Debut Research 1979[2] Isoproterenol has most Β2 vasodilatory and Β1 HR effects |
Dopamine | 2 mcg/kg/min | 20-50 mcg/kg/min | β1 and NorEpi release | α effects if > 20mcg/kg/min | Arrhythmogenic from β1 effects | More adverse events when used in shock compared to Norepi[3] |
Epinepherine | 0.1-1 mcg/kg/min | + inotropy, + chronotropy | ||||
Norepinephrine | 0.2 mcg/kg/min | 0.2-1.3 mcg/kg/min (5mcg/kg/min) [4] | mild β1 direct effect | β1 and strong α1,2 effects | Less arrhythmias than Dopamine[3] | First line for sepsis. Increases MAP with vasoconstriction, increases coronary perfusion pressure, little β2 effects. |
Milrinone | 50 mcg/kg x 10 min | 0.375-75 mcg/kg/min | Direct influx of Ca2+ channels | Smooth muscle vasodilator | PDE Inhibitor which increases Ca2+ uptake by sarcolemma. No venodilatory activity | |
Phenylephrine | 100-180 mcg/min then 40-60 mcg/min | 0.4-9 mcg/kg/min | Alpha agonist | Long half life | ||
Vasopressin | Fixed Dose | 0.01 to 0.04 U/min | unknown | increases via ADH peptide | should not be titrated due to ischemic effects | |
Methylene blue[5] | IV bolus 2 mg/kg over 15 min | 1-2 mg/kg/hour | Possible increased inotropy, cardiac use of ATP | Inhibits NO mediated peripheral vasodilation | Don't use in G6PD deficiency, ARDS, pulmonary hypertension |
Medication | IV Dose (mcg/kg/min) | Concentration |
Norepinephrine (Levophed) | 0.1-2 mcg/kg/min | 8mg in 500mL D5W |
Dopamine | 2-20 mcg/kg/min | 400mg in 250 D5W |
Dobutamine | 2-20 mcg/kg/min | 250mg in 250 mg D5W |
Epinephrine | 0.1-1 mcg/kg/min | 1mg in 250 D5W |
See Also
Source
- ↑ https://www.ncbi.nlm.nih.gov/pubmed/8449087
- ↑ Edmund H. Sonnenblick, M.D., William H. Frishman, M.D., and Thierry H. LeJemtel, M.D. Dobutamine: A New Synthetic Cardioactive Sympathetic Amine
- ↑ 3.0 3.1 De Backer Daniel et al. Comparison of Dopamine and Norepinephrine in the Treatment of Shock. NEJM 363(9). 779-789
- ↑ https://www.ncbi.nlm.nih.gov/pubmed/15542956
- ↑ Pasin L et al. Methylene blue as a vasopressor: a meta-analysis of randomised trials. Crit Care Resusc. 2013 Mar;15(1):42-8.