Hypovolaemia

Recognition

The history precipitating the cardiac arrest may suggest severe volume loss, such as trauma due to rupture of the liver or spleen, gastrointestinal bleeding or rupture of an aortic aneurysm. The signs and symptoms of hypovolaemia are illustrated in Table 11.4.

Response

Replacement of intravascular volume is of paramount importance while advanced life support continues.

Table 11.4 Signs and symptoms of hypovolaemia.

Tachycardia (rate >100 beats per minute)

Hypotension

Sweating

Pallor

Agitation

Thready or unpalpable distal pulses Prolonged capillary refill time (>2 seconds)

• For severe cases, a large-bore cannula should be placed into each antecubital fossa of the patient.

• The cannulae should be at least 16 G or 14 G in order to allow large amounts of fluid to be administered quickly.

• An alternative position for easy access is the external jugular vein of the patient. Two litres of crystalloid or colloid can then be administered as quickly as possible.

• There has been much controversy about the choice of fluid to be used in an emergency situation (Alderson et al. 2003). Saline 0.9%, Hartmann's solution or a colloid such as Gelofusin or Haemacel are all acceptable.

• The aim is to replace approximately 40% of the patient's circulating volume as quickly as possible.

• In high-dependency areas such as the emergency department, intensive care unit and theatres, infusion pumps may be available that can deliver 2 litres of warmed fluid to the patient in less than five minutes.

• Having administered the fluid, it is important to remember to reassess the effect at appropriate intervals in the algorithm. This is especially important if the patient is in pulseless electrical activity (PEA), as a palpable pulse may then be felt after this intervention.

• If the underlying cause of the cardiac arrest was haemorrhage, urgent surgery may be required if the resuscitation is successful in order to stop the haemorrhage.

Table 11.5 Normal serum electrolyte levels.

Electrolyte

Normal range

Potassium

3.5-5.0 mmol/l

Magnesium

>0.7mmol/l

Calcium

0.85-1.4 mmol/l (with albumin corrected)

0 0

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