Sunday, July 24, 2011

Adaptive Support Ventilation: Set it & forget it?

I once mentioned in a previous posting (Adaptive Support Ventilation: the Pareto Principle of Mechanical Ventilation) that “ASV requires little operator input and provides substantial benefits”. However this does not mean “set it & forget”, a phrase I  over-heard from an ASV in-service.
 This is not a Ronco Rotisserie Oven ® this is a mechanical ventilator and the operator needs to be engaged and assess patient-ventilator interaction.

Here are some areas of focus:

  1. Percent Minute Ventilation Setting: the operator needs to continually asses patient changes in minute ventilation demand.
    1. To appropriately off-load the work of breathing.
    2. To assure that the patient is not over-ventilated.
    3. One can adjust the percent minute ventilation setting based on the “ASV target point”.

  1. Trigger Setting: the trigger setting for spontaneous breaths needs to be appropriate set to prevent trigger asynchronies.

  1. Pressurization rate (aka. Rise time): a appropriate pressurization rate is needed to prevent patient discomfort (too fast) and decrease inspiratory work (too slow).

  1. Dynamic Lung: a quick & easy tool for monitoring changes in the patients pulmonary mechanics, EtCO2, and spontaneous activity..

  1. Vent Status: the Vent Status tool is a nice feature to quickly determine if the patient is ready for liberation from mechanical ventilation. 

6. ETS Setting (Expiratory Trigger Sensitivity): a inappropriate ETS setting may lead to "Premature Cycling" or "Delayed Cycling".