Investigations after restoration of circulation

Question 1

Full blood count

Answer 1

To exclude anaemia as contributor to myocardial ischaemia and provide baseline values

Question 2

Biochemistry

Answer 2

> To assess renal function

> To assess electrolyte concentrations (K+, Mg2+ and Ca2+)*

> To ensure normoglycaemia

> To commence serial cardiac troponin measurements

> To provide baseline values

• Immediately after a cardiac arrest there is typically a period of hyperkalaemia. However endogenous catecholamine release promotes influx of potassium into cells and may cause hypokalaemia. Hypokalaemia may cause ventricular arrhythmias. Give potassium to maintain the serum potassium between 4.0-4.5 mmol l-1.

Question 3

12-lead ECG

** Normal sinus rhythm is required for optimal cardiac function. Atrial contraction contributes significantly to ventricular filling, especially in the presence of myocardial disease and valve disease. Loss of the sequential atrial and ventricular contraction of sinus rhythm may reduce cardiac output substantially in some patients

Answer 3

To record cardiac rhythm**

To look for evidence of acute coronary syndrome

To look for evidence of old myocardial infarction

To detect and monitor abnormalities (e.g. QT prolongation)

To provide a baseline record

Question 4

Chest radiograph

Answer 4

To establish the position of a tracheal tube, a gastric tube, and/or a central venous catheter

To check for evidence of pulmonary oedema

To check for evidence of pulmonary aspiration

To exclude pneumothorax

To detect unintended CPR sequelae (e.g. sternal, rib fracture)

To assess cardiac contour (accurate assessment of heart size requires standard PA erect radiograph – not always practicable in the post-resuscitation situation)

Question 5

Arterial blood gases

Answer 5

To ensure adequacy of ventilation and oxygenation

To ensure correction of acid/base imbalance

Question 6

Echocardiography

Answer 6

To identify contributing causes to cardiac arrest.

To assess size/function of cardiac structures (chambers, valves), presence of pericardial effusion

To identify cardiac arrest associated changes (e.g. oedema)

Question 7

Cranial Computed tomography

Answer 7

If the immediate cause of cardiorespiratory arrest is not obvious

To identify causes to cardiac arrest (subarachnoid/subdural haemorrhage, intracerebral bleeding, tumour)

Question 8

Algoritm 2

• > Circulation
  - > Ultraljud kan användas, särskilt vid PEA, för att upptäcka:

Answer 8

• akinesi
• perikardvätska med tamponad
• högerkammardilatation talande för massiv lungemboli (dock av oklar valör vid långdraget hjärtstopp)
• djupventrombos i nedre extremitet, vilket talar för massiv lungemboli i detta sammanhang
• hypovolemi och eventuell orsak såsom intraperitoneal blödning eller bukaortaaneurysm
• hyperdynamiska hjärtkontraktioner talande för hypovolemi