The mandatory breath begins as a pressure-controlled breath, but ...

[cartlidgeashley]

The mandatory breath begins as a pressure-controlled breath, but it switches to volume control during inspiration because a preset volume is not achieved. This describes which of the following control types?
 
  a. Set-point c. Auto-set-point
  b. Adaptive d. Knowledge-based

Question 2

Which of the following ventilator control types consists of the output of the ventilator automati-cally matching a constant operator-preset input value?
 
  a. Optimal c. Auto-set-point
  b. Set-point d. Knowledge-based

[frejo]

Answer to Question 1

ANS: C
In this example, inspiration is starting out in pressure control and then switches to volume control by using operator-adjusted set-points. One type of mode that fits this category of control types is pressure augmentation (BEAR 1000). In the set-point control type, the output of the ventilator automatically matches a constant operator-preset input value. The adaptive control type changes set-point types based on the patient's changing condition. The knowledge-based control type has the set-points automatically adjusted according to a rule-based expert system, such as breathing frequency, tidal volume, and end-tidal carbon dioxide levels.

Answer to Question 2

ANS: B
A set-point control-type example mode is available in volume-controlled intermittent volume ventilation; in this mode, mandatory breaths are volume limited and volume cycled for the tidal volume setting. Optimal control has one ventilator set-point automatically adjusted to optimize another set-point according to some model of system behavior, and the output can be maximized or minimized dynamically. The auto-set-point control type enables the ventilator to select which operator-adjusted set-points are enforced at the moment. The knowledge-based control type has set-points that are automatically adjusted according to a rule-based expert system.