|The University of Kansas |
Respiratory Care Education
The primary purpose of covering the MA-1 is for the student to understand the difference between open and closed add-on IMV systems and the importance of calculating the patient's continuous flow requirements.
|An open IMV system may be used when the patient is not receiving PEEP. Note that the "H" valve is on the humidifier outlet (1) and that an APN is supplying gas to the H valve. On the other end of the H valve, corrugated tubing makes up a reservoir. The patient will breathe spontaneously through the H valve which is at ambient pressure. Note that no modifications were made to the Bennett spirometer or to the ventilator humidifier. The cascade still has its tower in place (2).|
|If PEEP is used, a closed IMV system should be added since the H valve will no longer at be at ambient pressure. A closed IMV system provides continuous flow and keeps the H valve at the PEEP pressure. A 5 liter bag (1) is connected to the H valve which is attached to the humidifier inlet (3). Blended gas from AIR or O2 teed together or from a blender flowmeter is supplied to the top of the bag. The tower is removed from the cascade (2). Since there will be continuous flow from the bag going through the circuit, a leak must be created in the elbow of the spirometer (4) to prevent the bellows from filling and pressurizing exhalation. The flow going to the reservoir bag should exceed the patient's spontaneous peak inspiratory flow. Total flow requirements are calculated as 4 x pt spont minute ventilation.|
Be able to answer the following questions.
1. What's important to do after connecting the circuit?
2. What's the patient disconnect alarm?
3. Which controls should be OFF?
4. What High Pressure Limit do you set before connecting to the patient?
5. How should you set the Bennett Spirometer Alarm before connecting to the patient?
6. How should you set the sensitivity before connecting to the patient?
7. What should you do if the High Pressure Alarm sounds immediately upon connecting the ventilator to the patient?
8. How can you tell if the inspiratory flowrate is inadequate?
9. How can you tell if the patient or the ventilator initiated the breath?
10. What do you have to do to the sensitivity when you add PEEP?
RC Ed WebMaster