EAC Clinical Shock Flashcards
define:
Shock
Shock is characterised by impaired cellular function as a result of a reduction in effective circulating blood volume
three intact mechanisms the body requires to function normally
Effective heart (pump)
Intact and functioning blood vessels (pipes)
Adequate volume of blood (fluid)
pathophysiology of shock
Insufficient O2 for aerobic metabolism
Cells produce energy via anaerobic metabolism
inefficient process resulting in excess lactic acid
Shock = this failure of energy production
define:
Hypovolemic Shock
Inadequate volume of blood
define:
Cardiogenic Shock
Failure of heart (pump)
define:
Neurogenic Shock
Loss of vasomotor tone
define:
Septic Shock
Septicaemia
causes of:
Hypovolemic Shock
Whole blood loss - internal/external bleeding
Plasma loss - burns
Electrolyte/Water loss - D and V
causes of:
Cardiogenic Shock
Heart failure
MI
Myocarditis
Tension pneumothorax
Cardiac tamponade
causes of:
Neurogenic Shock
High spinal cord injury - blood vessels relax dropping BP
Poisons
Fainting
causes of:
Septic Shock
meningococcal meningitis
Peritonitis
Cardiac conditions e.g. myocarditis
compensatory mechanism for:
Hypovolemic Shock
Sympathetic nerves increase venous tone
Reserve blood volume is mobilised from peripheral veins
Reduction in total circulatory capacity
in these ways the body tries to match the available blood volume.
compensatory mechanism for:
Hypovolemic Shock
If this is not adequate:
Heart rate will increase flow to vital organs
Selective constriction or arteries supplying non-vital organs to reduce their share of the lowered cardiac output (CO=SVxHR)
As venous return continues to fall, right heart filling is impaired and stroke volume reduced
Heart becomes unable to refill adequately between its contractions and fails to perfuse the heart muscle itself
Cardiac arrest and death could follow
Hypovolemic Shock Stage 1
Upto 15% blood volume loss
Normal RR 12-20
Pallor of skin
Normal capillary refill
Pulse rate >100bpm
No change in systolic or diastolic BP
Hypovolemic Shock Stage 2
15-30% blood volume loss
Increased RR 15-30/min
Pallor, cool, clammy skin
Extended time for capillary refill
Pulse rate >100bpm
Normal systolic BUT elevated diastolic BP (narrowing pulse)
Hypovolemic Shock Stage 3
30-40% blood volume loss
Anxiety, restlessness and agitation
Increased RR 30-40/min
Pulse rate >120bpm
Falling systolic BP to 100mmHg or less
Hypovolemic Shock Stage 4
Over 40% blood volume loss
Moribund appearance
Signs of respiratory distress 40+/min
Central cyanosis
Altered level of consciousness
Marked tachycardia/weak pulse
Systolic BP 70mmHg or less
additional considerations for shock in a pregnant patient
Signs of shock appear late in pregnant pt’s
Hypotension is an extremely late sign indication stage 3 shock
Consider pt position onto left side due to foetal compression on the inferior vena cava
HR is increased by 10-15BPM during pregnancy
BP falls 10-15mmHg during pregnancy
Cardiac output increases 20-30% during first 10 weeks of pregnancy
Blood volume increases during pregnancy, but unproportionately causing anaemia
management of:
Shock
DRABCDE Assess for time critical High % O2 If conscious: position flat with head and shoulders slightly raised If unconscious: in stable side position Raise lower limbs Treat other injuries and bleeding Do not overheat or allow to become cold Avoid rough handling, be gentle Constant reassurance Constant Observations Nil by mouth Time critical transfer to appropriate facility - pre alert Consider paramedic/HEMS help
Considerations for early paramedic/HEMS intervention for Shocked patients
Immediate surgery
Better pain relief
Paramedic/HEMS drugs - coagulant
