Cardiac Arrest

Question 1

What are the 4 Hs

(reversible causes of cardiac arrest)!

Answer 1

Hypoxia

Hypovolemia

Hypometabolic state

Hypothermia

Question 2

How can we correct Hypoxia

Answer 2

Oxygenate

Is the patient being adequately ventilated? Is the BVM connected to 100% oxygen supply? Remember to check regularly how much oxygen is left if using a portable supply.

Question 3

How can we correct Hypovolemia?

Answer 3

Apply direct or indirect pressure to a wound causing catastrophic blood loss.
Remember to check for signs of internal bleeding.

Raise the legs- use gravity to increase circulation volume in the upper body.

Can we deliver fluid therapy or gold standard- some matched blood products.

Question 4

How can we correct deranged metabolic state

Answer 4

Check Blood glucose (BM) is low deliver IV glucose (10mg in 100ml of 10% glucose)

Reassess BM further bolus maybe given.

Max dose 30mg (100ml)

Question 5

How can we correct Hypothermia?

Answer 5

Check temperature with a tympanic thermometer (gold standard - rectal or oesophageal thermometer)

Warm the patient

If Temp between 30-35°C double interval of Adrenaline.

Question 6

What are the 4Ts

(Reversible causes of cardiac arrest)

Answer 6

Thrombus- occlusion of a cardiac artery-ensure good CPR - compressions at a depth of 1/3 of the depth of the chest- 100-120 a minute, allowing full recoil of the chest. —Ensure time off the chest is kept to the minimum necessary.

Toxins - check the size of the patients pupils / any sign or Hx of opioid drug use ? any Hx of suicidal intent? Deliver naloxone hydrochloride- IV- initial dose 400mcg, 1 minute interval, repeat dose 800mcg to a maximum of 10000mcg (12 repeat doses)

Tension pneumothorax- check for equal rise and fall of the chest while bagging / think about Hx and mechanism / check for tracheal deviation below the sternal notch - if suspected carry out needle thoracostomy (large bore cannula inserted into the second intercostal space, mid clavicular, along the superior border of the third rib to ensure missing the neurovascular bundle)

Tamponade- Does the mechanism of injury suggest injury to the pericardium or cardiac muscle likely (Haemorrhage can be caused by a ruptured cardiac artery due to occlusion Myocardial infarction). If yes good CPR should continue but we need to think about calling for assistance from MERIT/ HEMS or convey to a trauma centre able to drain the tamponade.