Shock Flashcards
What are the steps of managing shock?
- Identify the presence of shock
- Identify the probable cause of shock
- Initiate treatment
Types of shock?
- Hypovolaemic/haemorrhagic
- Obstructive
- Cardiogenic
- Neurogenic
- Septic
Most common cause of shock in trauma patients?
Haemorrhagic shock
Possible causes of confusion in a trauma patient?
- Shock of any cause
- Brain injury
- Stroke
- Alcohol & drugs
What is cardiac output?
HR x SV
What are the determinants of SV?
- Preload
- Myocardial contractility
- After-load
What are the determinants of preload?
- Venous capacitance
- Volume status
- Venous flow due to pressure differential
Factors reducing preload?
Haemorrhage
What is afterload?
This is the resistance to the forward flow of blood
What are the early physiological responses to blood loss?
- Increased vasoconstriction - Vital organs
- Increased HR to preserve cardiac output
- Increased catecholamines to increase PVR & DBP
- Shift from aerobic to anaerobic metabolism
Blood loss and compensatory mechanisms ?
They maintain normal conditions until 30% of blood volume is lost
Best laboratory indicators for the severity of shock?
- Lactate
- Base deficit
Other causes of shock & volume resuscitation?
Other forms of shock transiently improve with volume resuscitation
What is the normal adult & child blood volume?
- 7% of body weight
- 7% of ideal body weight in the obese patient
- 8-9% of body weight in the paediatric group
What is the physiological classification of haemorrhage ?
Class 1: Minimal changes - EBL 1 unit of RBC
Class 2: Requiring crystalloid resuscitation
Class 3: Crystalloid & blood required
Class 4: Mass EBL - Death in minutes
Class 1 haemorrhage & physiological changes?
- Blood loss <15%
- Normal BP, pulse pressure & RR
- BE 0 to -2
Class 2 haemorrhage & physiological changes?
- 15 - 30% EBL
- Tachycardia & tachypnoea
- Decreased pulse pressure
- Subtle CNS signs - Anxiety, agitation
- UO = 20-30ml/hr
- BE -2 to -6
- Crystalloid resuscitation
Class 3 haemorrhage & physiological changes?
- EBL 31-40%
- PRBC, crystalloid & control of bleed required
- Inadequate perfusion
- Tachycardia & tachypnoea
- Significant CNS changes - Confusion
- Significantly low BP
- BE -6 to -10
Class 4 haemorrhage & physiological changes?
- Significant tachycardia & hypotension
- Narrow pulse pressure
- Oliguria
- Depressed CNS
- Cold & pale skin
- BE -10 or more
- Rapid transfusion & control required
What are the usual methods of haemorrhage control?
- Angio-embolization
- Direct pressure
- Operation
- Pelvic binder or sheet
- Splint fracture
- Tournique
Possible sources of bleeding?
- Floor & 4 more
- Abdo/pelvis
- Retroperitonium
- Thorax
- Extremities
Indicator for adequate resuscitation?
UO > 0.5ml/kg/hr (Adult)
UO > 1ml/kg/hr (Child)
UO > 2ml/kg/hr (Infant)
Types of response to resuscitation?
- Rapid
- Transient
- Minimal
Control of haemorrhage?
- Operative
- Angiographic control - Embolization
