Shocks in Adults

Types:
1. Hypovolemic - decreased preload due to volume loss
2. Cardiogenic - cardiac pump failure
3. Distributive (vasodilatory) - severely decreased SVR
4. Combined - ex. septic shock

Types	Preload	Pump Function	Afterload	Tissue Perfusion
Measurement	PCWP	CO	SVR	SvO2
Hypovolemic	↓	↓	↑	↓
Cardiogenic	↑	↓	↑	↓
Distributive	↓/↔	↑	↓	↑

Stages of Shock:

1. Preshock

2. Shock

3. End-organ dysfunction

Clinical Manifestations
1. Cardinal findings: 

    A. Hypotension, oliguria, AMS, cool + clammy skin, metabolic acidosis
2. Hypovolemic
    A. Blunt/penetrating trauma/post-operative.
    B. Hematemesis, hematochezia, melena, vomiting, diarrhea, or abdominal pain
    C. PE: decreased skin turgor (in younger patients), dry skin, axillae, tongue or dry oral mucosa, postural hypotension, ↓JVP, ↓CVP
    D. Categories:
        a. Hemorrhage-induced
        b. Fluid loss induced
3. Cardiogenic
    A. History of CVD, acute onset of recurrent chest pain, SOB,  new or worsening hypotension, tachycardia, tachypnea
    B. PE: diffuse crackles, new murmur, gallops, or soft heart sounds. ↑JVP, ↑CVP , ↓distal pulses
    C. CXR: pulmonary edema
    D. ECG: ischemia
    E. Lab: ↑cardiac enzymes
    F. Categories:
        a. Cardiomyopathies - ex. AMI
        b. Arrhythmias - ex. AF, Af, VT, VF, complete AVB
        c. Mechanical - Valvular disease, VSD, ruptured ventricular free wall aneurysm
        d. Extracardiac - massive PE, tension pneumothorax, severe constrictive pericarditis, pericardial tamponade, Eisenmenger's
4. Distributive
    A. Depends on cause
    B. Dyspnea, productive cough, dysuria, hematuria, chills, myalgias, rashes, fatigue, malaise, HA, photophobia, pain.
    C. PE: Fever, tachypnea, tachycardia, leukocytosis, AMS, or flushing.
    D. Categories:
        a. Septic shock
        b. SIRS
        c. Toxic Shock Syndrome
        d. Anaphylaxic
        e. Drug/Toxin
        f. Addison Crisis
        g. Myxedema coma
        h. Neurogenic shock
        i. Acute systemic inflammation following AMI
        j. Post-resuscitation
        k. Post-cardiopulmonary bypass

Diagnostic Approach
1. Hx
2. PE
3. Lab:
    A. CBC + DC, Na+, K+, Cl-, HCO3-, BUN/CRE, AST/ALT, amylase, lipase, PT, PTT, INR, fibrinogen, D-Dimer, Troponin T+I, CPK, CK, lactate, toxicology screen
    B. ABG
    C. Culture x 2 + U/A
4. EKG
5. Image: CXR, KUB, Abdominal CT, or head CT may be helpful
6. If shock remains undifferentiated --> pulmonary artery catheterization 
    A. But no improvement in outcome

Pulmonary Artery Catheterization
1. Indications:
   A. Differentiation of shock/pulmonary edema
   B. Evaluation of pulmonary HTN
   C. Diagnosis of pericardial tamponade, left-to-right intracardiac shunt or lymphangitic spread of tumor, fat embolism
   D. Unstable cardiac status
   E. Complicated MI
   F. Following cardiac surgery
   G. Management of Severe preclampsia
   H. Pharmacologic therapy - vasopressors, inotropics, vasodilators in pul. HTN pts
   I. Non-pharmacologic therapy
   J. Ventilator management (assessment of best PEEP for O2 delivery)
2. Complications:
   A. Vascular inflammation/rupture
   B. Valvular damage
   C. Arrhythmia
   D. Pulmonary artery rupture
   E. Pulmonary infarction
   F. Thromboembolic events - mural thrombi
   G. Misinterpretation of the data

(Reference: Uptodate)