Critical Care Emergencies 17SHOCKED PATIENT(i) Hypovolaemic shock (‘insufficient circulatory volume’) (see
p. 19):
(a) haemorrhagic – traumatic or non-traumatic; external
(revealed) or internal (concealed)
(b) non-haemorrhagic fluid losses – external (revealed), internal
(concealed).
(ii) Cardiogenic shock (‘pump failure’):
(a) decreased contractility – acute coronary syndrome,
myocarditis, myocardial contusion, end-stage
cardiomyopathy, drug toxicity, severe acidaemia
(b) acute valvular dysfunction – acute valve leak (papillary
muscle/chordae tendinae rupture, infective endocarditis),
severe aortic stenosis
(c) arrhythmia – tachycardia such as SVT, AF or VT,
bradycardia including heart block.
(iii) Distributive shock (‘infinite circulation, unable to be filled’):
(a) sepsis (see p. 21)
(b) anaphylaxis
(c) neurogenic – spinal cord trauma, epidural
(d) drug-related – nitrates, vasodilators
(e) adrenal insufficiency – inadequate steroid replacement,
Addison’s.
(iv) Obstructive shock (‘obstructed circulation’):
(a) pulmonary embolism – thrombotic, air, fat, amniotic fluid
(b) tension pneumothorax – traumatic, non-traumatic
(c) cardiac tamponade – traumatic, non-traumatic such as
uraemia, pericarditis, malignancy
(d) dynamic hyperinflation – over-ventilated asthma, or COPD.4 Ask about the onset whether sudden or gradual, associated symptoms such
as chest pain, abdominal or back pain, and the past medical history, drugs
taken including illicit drugs, allergies, recent travel abroad, alcohol use or
immunosuppression and prior cardiorespiratory status.
5 Assess for features of circulatory shock including abnormal vital signs.
(i) Tachycardia occasionally bradycardia, tachypnoea, hypotension,
hypothermia (or hyperthermia in sepsis), reduced oxygen
saturation and a reduced conscious level (Glasgow Coma Scale
[GCS] score) occur
(a) check for a postural change in blood pressure, if the SBP is
normal
- increase in heart rate of >20 beats/min, a fall in SBP of
20 mmHg, or a fall in DBP of >10 mmHg indicates pos-
tural hypotension and suggests hypovolaemia
- make certain the orthostatic readings are taken after at least
2 min sitting or standing up.