The respiratory therapist preparing to insert an arterial line in ...

[justinmsk]

The respiratory therapist preparing to insert an arterial line in the right radial artery performs an Allen test. The result of the Allen test is 20 seconds. The respiratory therapist should do which of the following?
 
  a. Insert the cannula into the right radial ar-tery.
  b. Repeat the Allen test on the right hand.
  c. Perform an Allen test on the left hand.
  d. Recommend a surgical cut down at the right radial site.

Question 2

Which of the following is the function of the transducer in the invasive vascular monitoring sys-tem?
 
  a. Measure the flow of fluid in the catheter.
  b. Convert the fluid pressure to an electrical signal.
  c. Connect to the thermistor to measure car-diac output.
  d. Amplify the electrical signal so it may be seen on the monitor.

[frogdreck123456]

Answer to Question 1

ANS: C
The purpose of the Allen test is to assess the adequacy of the collateral circulation to the hand, specifically ulnar circulation. A positive Allen test is a refill time of 5-10 seconds. This patient has a negative Allen test (23 seconds). Therefore, ulnar collateral circulation is insufficient and the right radial artery of this patient must not be cannulated. Another site, the left radial, should be assessed for collateral circulation.

Answer to Question 2

ANS: B
The transducer has two main compartments. One, called the dome, contains the fluid that enters it from a plastic line connected to the indwelling catheter. The dome is separated from the elec-trical portion of the transducer by a flexible diaphragm. Changes in fluid pressure result in movement of the diaphragm, which causes an increase or decrease in the length of the wires of the Wheatstone bridge contained in the electrical portion of the transducer. The transducer is therefore able to detect small physiological signal changes and convert them to electrical impulses or signals.