Undifferentiated shock
(Redirected from Hypovolemic)
This page is for adult patients. For pediatric patients, see: undifferentiated shock.
Overview
- Inadequate perfusion of the tissues
- Goal to increase the flow of oxygenated blood to the tissues
- MAP<50 in dog studies brain will become ischemic and patients might presents as an altered mental status [1]
Undifferentiated Hypotension Algorithm[2]
Check/manage the following in order:
- Pulse (assess based on patient's age)
- Volume status
- What is the LV end-diastolic volume?
- Approximated by the IVC diameter or CVP
- If low:
- Assess for blood loss versus fluid loss
- FAST for intra-abdominal bleed
- US for ruptured AAA
- Guaiac for GI bleed
- CXR for hemothorax
- Treat with IVF and/or pRBCs depending on cause
- Assess for blood loss versus fluid loss
- What is the LV end-diastolic volume?
- Contractility
- Is the myocardium severely depressed in its contractile function (cardiogenic shock)?
- Assess via ultrasound
- Treat with inotrope (e.g. epinephrine, dopamine
- Is forward flow occurring?
- 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)
Evaluation
Shock index (SI)[3]
SI = HR / SBP
- Used when HR and SBP do not predict severity of hypovolemia in early stages
- May be used as secondary triage tool in mass casualty incidents[4]
- 0.5-0.7 is normal
- >0.70-0.75 for occult shock or requirement of life-saving intervention
Simple Shock Index (sSI) was recently proposed. Subtracting SBP from HR is a good SI substitute. Working with integers is easier than dividing them, improving value availability.[5]
Consider RUSH to CVS
- RUSH exam
- Calcium bolus as inotrope
- Vasopressin
- Steroids, stress-dose, mineralocorticoids
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) [6] | Strong ß1 agonist +inotrope +chronotrope, Weak ß2 agonist +weak vasodilatation ) | alpha effect minimal | HR variable effects. | indicated in decompensated systolic HF, Debut Research 1979[7] 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[8] |
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) [9] | mild β1 direct effect | β1 and strong α1,2 effects | Less arrhythmias than Dopamine[8] | 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[10] | 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 |
Causes of non-response to vasopressors[11]
- Acidosis
- Dx: Blood gas, BMP
- Tx: treat underlying cause, consider bicarbonate gtt
- Hypothyroidism
- Dx: Clinical, TSH
- Tx: levothyroxine
- Anaphylaxis
- Dx: History
- Tx: Epinephrine, methylene blue, ECMO
- Adrenal insufficiency
- Dx: Clinical, cortisol level, hyperkalemia + hyponatremia
- Tx: Hydrocortisone 100-200mg
- Hypocalcemia
- Dx: ionized calcium, prolonged QTc
- Tx: Calcium chloride or calcium gluconate
- Occult bleeding
- Dx: Clinical (consider GI bleed and retroperitoneal hematoma)
- Tx: Transfusion, treat coagulopathy, surgery/IR interventions
- Toxicologic
- Dx: Clinical (consider beta blocker toxicity, calcium channel blocker toxicity, TCA overdose, etc)
- Tx: Depends on etiology (glucagon, hyperinsulin euglycemia therapy, sodium bicarbonate, ECMO, etc)
- 2nd cause of shock
- Dx: Clinical, consider RUSH exam
- Tx: Address underlying cause
See Also
External Links
References
- ↑ Plöchl, W, D J Cook, T A Orszulak, and R C Daly. 1998. Critical cerebral perfusion pressure during tepid heart operations in dogs. The Annals of thoracic surgery, no. 1. http://www.ncbi.nlm.nih.gov/pubmed/9692450
- ↑ Morchi R. Diagnosis Deconstructed: Solving Hypotensionin 30 Seconds. Emergency Medicine News. 2015.
- ↑ Levitan, Richard M. Fundamentals of Airway Management. 3rd ed. Irving, TX: Emergency Medicine Residents' Association, 2015.
- ↑ Vassallo J et al. Usefulness of the Shock Index as a secondary triage tool. J R Army Med Corps. 2015 Mar;161(1):53-7.
- ↑ Kamikawa Y, Hayashi H. Equivalency between the shock index and subtracting the systolic blood pressure from the heart rate: an observational cohort study. BMC Emergency Medicine. 2020 Dec;20:1-8.
- ↑ 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
- ↑ 8.0 8.1 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.
- ↑ Anand Swaminathan, "Occult Causes of Non-Response to Vasopressors", REBEL EM blog, July 13, 2017. Available at: https://rebelem.com/occult-causes-of-non-response-to-vasopressors/.
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