Shock Flashcards
Definition of shock
Inadequate tissue perfusion leading to cellular hypoxia of peripheral tissues with possible progression to end organs
Types of shock
Cardiogenic
Hypovolemic
Distributive
Obstructive
Definition of cardiogenic shock
inadequate tissue perforation due to myocardial dysfunction (pump failure)
PAWP > 16mmHg
SBP <90mmHg
CI < 2.2 L/min/m2
Definition of anaphylactic shock
Type 1 IgE mediated hypersensitivity reaction
Management of anaphylactic shock
Secure airway
Remove antigen
Fluid resuscitation
Adrenaline 0.5mg 1:1000 IM or 50 mcg IV
Chlorpheniramine 10mg IV
Hydrocortisone 200mg IV
Consult ICU
Main types of inotropes
- Catecholamines
- Phosphodiesterase inhibitors
- Cardiac glycosides
- Endogenous peptides
Clinical features of cardiogenic shock
Cool peripheries
Decrease urine output
Decrease consciousness
Increase JVP
Volume overload
Hepatomegaly
What is the mechanism of action for catecholamines?
Affinity for different subclasses of adrenergic receptors
- alpha : vasoconstriction
- beta 1: myocardial contractility
- beta 2: increase HR (and vasodilation)
What is the mechanism of action for phosphodiesterase inhibitors? Examples
- inotropic
- vasodilator
Milrinone, Amrinone
What is the mechanism of action of cardiac glycosides?
Inhibit Na+/K+ ATPase in cell memebrane
Inotropic
Ex. Digoxin
What receptors does noradrenaline act on?
Alpha > Beta: alpha 1 +++, beta 1 +
Use: septic shock
SE: tachycardia/reflex bradycardia, limb/GI ischemia
What receptors does adrenaline act on?
Beta > Alpha: αlpha 1 ++, β1 +++, β2 ++
Use: cardiac arrest, low CO state
What receptors the phenylephrine act on?
Alpha 1
Pure vasoconstrictor
Used if arrhythmia is a problem
What receptors does dopamine act on?
Mainly dopaminergic (DA1 +++)
B1 and B2 +
Alpha 1+
What receptors does vasopressin act on?
V1R on vascular smooth muscles: vasoconstriction
V2R: renal + endothelium vasodilation
V3R: pituitary
Use: to increase SVR in septic shock
What receptors does dobutamine work on?
Beta 1 and 2
Use: low CO state, cardiac surgery
Examples of inotropes
Adrenaline
Dobutamine
Isoprenaline
Ephedrine
Examples of vasopressors
Noradrenaline
Vasopressin
Examples of inodilators
Milrinone
Levosimendan
Clinical manifestation of hypovolemic shock
- Decrease BP
- Tachycardia
- Peripheral vasoconstriction
- Low JVP
Clinical manifestations of septic shock
- Decrease BP
- Tachycardia
- Peripheral vasodilation
- Low JVP
- Peripheral / pulmonary edema
Clinical manifestations of neurogenic shock
- Decrease BP, no tachycardia
- Cutaneous vasodilation
- Narrow pulse pressure
Clinical manifestations of anaphylactic shock
- Decrease BP
- Tachycardia
- Edema
Class 1 anti-arrhythmic drug
Sodium channel blockers
1a: moderate NA block with prolonged repolarisation ex procainamide
1b: midl NA block with shortened repolarisation ex. lidocaine, phenytoin
1c: marked Na block with no change in repolarisation. ex Flecainide
Class 2 anti-arrhythmic drugs
Beta blockers
Ex. Propranolol, Metoprolol
Class 3 anti-arrhythmic drugs
Potassium channel blockers
ex. Amiodarone, Sotalol
Class 4 anti-arrhythmic drugs
Calcium channel blockers
Ex. Diltiazem, Verapamil
What are inodilators
Increase myocardial contraction and systemic vasodilation
What are components of a invasive monitoring system?
- Intravascular catheter
- Continuous column of fluid
- Transducer (strain gauge connected to distensible diaphragm)
- Amplifier
- Display
How do you monitor cardiac output non-invasively?
- Analysis of arterial pressure waveform
- Oesophageal Doppler monitor
- Thoracic impedance techniques
