Anesthetic Delivery Systems

Question 1

1. The volume of which of the following gases cannot be accurately estimated from the cylinder pressure gauge?
   
   1. Oxygen
   2. Nitrous oxide
   3. Carbon Dioxide
   4. All of the above

Answer 1

1. Nitrous oxide

Question 2

1. In the event that a pipeline crossover is suspected during a case, which two corrective actions should be undertaken immediately?
   
   1. Change the oxygen cylinder
   2. Open the backup oxygen cylinder.
   3. Bag-valve mask the patient until the problem is identified.
   4. Disconnect the pipeline gas
   5. Discontinue nitrous oxide and place the patient on 100% oxygen

Answer 2

1. Open the backup oxygen cylinder.
2. Disconnect the pipeline gas

Question 3

1. If the oxygen flow is 2L/min, and the cylinder’s oxygen gauge pressure is 500 psi, how long will the cylinder last?
   
   1. 2280 min
   2. 158 mins
   3. 1583 mins
   4. 174 mins
   5. 87 mins

Answer 3

1. 87 mins
   
   1. 660 L/1900 psi = x L / 500 psi
   2. x= 174L
   3. At a 2 liter flow per minute, the cylinder will last 87 mins (174/2Lmin).

Question 4

1. A nitrous oxide E-Cylinder wighs 5.9 kg empty, or 9.0 kg full. The pressure gauge reads 745 psi and the cylinder now weighs 7kg. How many liters of nitrous oxide are remaining in the cylinder at standard temperature and pressure (STP)? (The molecular weight of N2O is 44g/mol; 1 mole of nitrous oxide at STP is 22.4 L.)
   
   1. 1590
   2. 3004
   3. 560
   4. 220
   5. 1020

Answer 4

1. 560
   
   1. To solve this, you need to calculate the mass remaining in the cylinder (7-5.9=1.1kg) Then convert to grams (1100g) and divide by the molecular weight. This gives you 25 moles. Now multiply by the standard volume to get 560L. You can also calculate it based on the amount used. Just subtract the answer from the volume of a full cylinder. It’s an extra step, but equally valid.

Question 5

1. Which of the following represent components of the low pressure pneumatic system in an anesthesia gas machine? (Choose all that apply.)
   
   1. Hanger Yoke
   2. Flush Valve
   3. Vaporizer
   4. Cylinder pressure gauge
   5. Flowmeter tubes
   6. Common gas outlet

Answer 5

1. Vaporizer
2. Flowmeter tubes
3. Common gas outlet