Shock Flashcards
Describe the 4 stages of shock
- Initial- tissues under perfused, increased metabolic rate and lactic acid accumulation
- Compensatory - Sympathetic NS activated
- Progressive - failing compensatory mechanisms, metabolic acidosis due to ischemia and lactic acid production
- Refractory - cellular necrosis and multiple organ dysfunction syndrome
Pathophysiology of shock x4
- Decreased myocardial contractility
- Systemic lactic acidosis
- Decreased vascular tone
- Decreased BP, preload and CO
External fluid loss causes of hypovolemic shock x5
External fluid loss:
Hemorrhage
Dehydration- Vomiting, diarrhea, burns, massive diuresis
Internal fluid loss causes of hypovolemic shock x3
Loss of vascular integrity
Increased capillary membrane permeability
Decreased colloidal osmotic pressure
Hypovolemic shock therapy x5
ABC
Stop obvious bleeding
Insert IV lines and take GXM
Give rapid bolus and reassess
Investigations vs surgery
Signs of cardiogenic shock x6
Raised JVP
Cold skin
Tachycardia
Engorged liver
Peripheral edema
Added heart sounds S3(V gallop) S4(A gallop)
Causes of cardiac shock x5
Acute myocardial infarction
Severe arrhythmias
Severe valve disease
Tension pneumothorax
Tamponade (obstructive too)
Mechanical complications of myocardial infarction that cause CG shock x3
Papillary muscle rupture
Ventricular aneurysm
Ventricular septal rupture
Decreased how CG shock can cause pulmonary edema x5
Decreased CO> increased LV filling pressure(preload) > increased LA filling pressure> increased capillary pressure> interstitial and intra alveolar edema
Interpretation of MAP- mean arterial pressure x2
<70mmHg = compromised coronary perfusion
<60mmHg = compromised renal perfusion
Signs of tension pneumothorax x5
Raised JVP
Tracheal deviation
Reduced chest expansion
Hyperresonant percussion
Diminished breath sounds
Treatment aim for CG shock x4
Treat reversible causes
Increase myocardial O2 delivery
Maximizing CO
Decreased LV workload
How to reduce myocardial damage during myocardial infarction x5
Vasoactive drugs- dopamine
Inotropic agents
Cautious administration of fluids
Intra aortic balloon pump
Transplantation
Short acting B blockers- reduced contractility of heart hence less o2 needed
Function of dobutamine x2
B1 receptor agonist - promotes cardiac stimulation
Mild B2 effects- vasodilation
Characteristics of distributive shock x2
Leaky blood vessels due to infection
Vasodilation > reduced vascular resistance
Describe how distributive shock results in decreased tissue perfusion
Vasodilation > decreased vascular resistance > blood moving too fast > less time to unload oxygen
OR
Decreased bp > less pressure to push out blood from vessels to tissues
Causes of distributive shock x3
Septic shock
Anaphylactic shock
Neurogenic shock
Anaphylactic response x5
Vasodilation, increased capillary permeability
Bronchoconstriction, increased mucus production
Increased inflammatory mediators
Recruitment to sites of antigen interaction
Management of anaphylactic shock x5
Airway support
Epinephrine IV
Antihistamines
Corticosteroids
Positive inotropes
Vasopressors
Pathophysiology of neurogenic shock x5
Disruption in sympathetic nervous system
Decreased sympathetic tone
Arterial and venous vasodilation
Decreased venous return, SV, CO
Impaired tissue perfusion and cellular metabolism
Goals of therapy in neurogenic shock x2
Treat and prevent CVS instability
Promote optimal tissue perfusion
Define septic shock
A life threatening organ dysfunction caused by dysregulated host response to an infection
3 Risk factors for sepsis
Reduced immunity
Extremes of age limiting communication
Recent surgery, invasive procedure, pregnancy or miscarriage
Conditions which increase risk of sepsis x5
Diabetes
HIV/AIDS
Liver cirrhosis
SCD, Splenectomy
Autoimmune diseases
Pathophysiology of septic shock x4
1.Vasodilation and increased capillary permeability
2.Endotoxins release inflammatory mediators
3.Cell walls of organisms release endotoxins
4. Initiated by gram neg and gram positive
Describe 2 phases of septic shock
Warm- early, vasodilation, hyperdynamic response
Cold- late, hypodynamic response, decompensated state
