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Applied Medical Knowledge(AMK) Question
A 75 year old female, presents to the emergency department in a state of acute respiratory distress. From her accompanying husband, Phil, you ascertain that she has suffered with chronic allergic asthma since childhood. She has brought both of her inhalers with her, and is carrying them in her right hand.
Tests reveal a heart rate of 115 beats/min, systolic blood pressure of 95 mmHg. Pulse oximetry reveals that oxygen saturation is 88%. PEF is 47%, and there is evidence of cyanosis of the lips.
Following initial stabilisation, the duty registrar suggests that you cannulate the patient to obtain arterial blood gas samples. What would be the most appropriate location for this procedure?
A) Right femoral artery
Incorrect. The femoral artery is used in emergencies for arterial blood gas sampling if an accessory artery cannot be accessed. However, its position as the major artery supplying the lower limb mean that any complications in the procedure any compromise the entire blood supply to that limb. In elderly patients especially, dislodgement of atheroma from the femoral artery may occur.
B) Left femoral artery
Incorrect. The tibial artery's position as the major artery supplying the distal lower limb mean that any complications in the procedure any compromise the entire blood supply to that part of the lower limb. It is also inaccessible for palpation and stabilisation.
C) Left radial artery
Correct. The radial artery has a good collateral supply from the ulnar artery, is near to the surface and is relatively easy to palpate and stabilise. The chance of atheroma dislodgement is small. As the patient is carrying items in her right hand, there is a clue that she is right hand dominant. The correct side for sampling would be the non-dominant side.
D) Right brachial artery
Incorrect. Although the brachial artery may be used for this procedure, is does not have the greatest combination of accessibility, risk minimisation and collateral supply. It may be used if other sites are not available. As the patient is carrying items in her right hand, there is a clue that she is right hand dominant. The correct side for sampling would be the non-dominant side.
E) Brachiocephalic trunk
Incorrect. The brachiocephalic trunk is not used for this procedure due to its inaccessibility and potential for complication.
F) Don't know
The radial artery has a good collateral supply from the ulnar artery, is near to the surface and is relatively easy to palpate and stabilise. The chance of atheroma dislodgement is small. As the patient is carrying items in her right hand, there is a clue that she is right hand dominant. The correct side for sampling would be the non-dominant side.