- clear airway and breathing.
- start TWO LARGE BORE (14-16G) IVs in the brachial/cephalic vein of each arm
- 1-2 L bolus of IV Normal Saline/Ringer’s Lactate
- consider common sites of internal bleeding (abdomen, chest, pelvis, long bones)
- Inadequate tissue perfusion:
Skin - cold, pale, 'clammy‘, blue, slow capillary refill
Kidneys - oliguria, anuria
Brain - drowsiness, confusion and irritability
- Increased sympathetic tone:
Tachycardia, narrowed pulse pressure, 'weak' or 'thready' pulse
Blood pressure fall (BP may be maintained initially despite up to a 25% reduction in circulating volume if the patient is young and fit)
Low central venous pressure (CVP) and pulmonary artery occlusion pressure (PAOP)
Low cardiac output
Increased systemic vascular resistance
patients have cool extremities due to peripheral vasoconstriction
- most common form of shock, due to decrease in intravascular volume
- exogenous losses (e.g. haemorrhage, burns) or endogenous losses
- hemorrhage, dehydration, vomiting, diarrhea, interstitial uid redistribution
- natural precursor of adrenaline which acts on β and α receptors, as well as dopaminergic receptors.
- low doses (1-3μg/kg/min) increase renal and hepatic flow and improve urine output
- moderate doses (3-10μg/kg/min) increase heart rate, myocardial contractility and cardiac output
- higher doses (>10μg/kg/min) increase noradrenaline production -- > vasoconstriction. This increases afterload and raises ventricular filling pressures.
- adrenaline - α and β activity, low doses α < β, at high doses risk of excessive vasoconstriction – typical dose 0,1-1,5 ug/kg/min
- noradrenaline – mostly α agonist, risk of excessive vasoconstriction - typical dose 0,05- 0,1 ug/kg/min
- dobutamine – β1 activity, increase in contractility, decreased afterload, typical dose 10 ug/kg/min
- afterload reduction may be used to increase stroke volume and decrease myocardial oxygen requirements by reducing the systolic ventricular wall tension. Vasodilatation also decreases heart size and the diastolic ventricular wall tension so that coronary blood flow is improved
- Nitroglycerine – mostly venous dilatation - in patients with cardiac failure and/or myocardial ischaemia – typical dose 0,1-1ug/kg/min
- Sodium nitroprusside – dilates arteries and veins (also pulmonary) – reduces both preload and afterload
- Airway (Open, clear, maintain)
- Breathing (oxygen supplementation, ventilatory support)
- Correct causes (haemorrhage, infection)
- Cardiac output:
preload: fluid replacement (blood, crystalloids, colloids – HES, dextran, albumin)
myocardial contractility –inotropic agents
afterload – vascular resistance
- Signs of myocardial failure - raised jugular venous pressure (JVP), pulsus alternans, 'gallop' rhythm, bilateral basal crackles, pulmonary oedema
- Increased systemic vascular resistance
- CVP and PAOP high (except when hypovolaemic)
Due to: Myocardial ischemia, Dysrhythmias, CHF, Cardiomyopathies, Cardiac valve problems, pharmacologic
- obstruction to outflow (e.g. pulmonary embolus), restricted cardiac filling (e.g. cardiac tamponade, tension pneumothorax)
- massive PE (saddle embolus), pericardial tamponade, constrictive pericarditis, increased intrathoracic pressure (e.g. tension pneumothorax)
- obstruction of blood into or out of the heart
- inadequate tissue perfusion resulting in generalized cellular hypoxia
failure of the heart to act as an effective pump
loss of circulatory volume
abnormalities of the peripheral circulation
- CVP (central venous pressure):
Describes the pressure of blood in veins near the right atrium of the heart.
CVP reflects the amount of blood returning to the heart and the ability of the heart to pump the blood into the arterial system.
Normal values are: 4-12cmH20
Increase CVP: hypervolemia, heart failure, cardiac tamponade, tension pneumothorax
Decrease CVP: hypovolemia, distributive shock
- PAOP (Pulmonary artery occlusion pressure)
The pressure is measured in a pulmonary artery distal to an occlusion of that artery.
Diagnose the severity of left ventricular failure
Normal pressure: 6-12mmHg.
When the pressure is >20mmHg, pulmonary edema is likely to be present
- Assessment of tissue perfusion:
Pale, cold skin, delayed capillary refill and the absence of visible veins in the hands and feet indicate poor perfusion
Metabolic acidosis with raised lactate concentration may suggest that tissue perfusion is sufficiently compromised to cause cellular hypoxia and anaerobic glycolysis.