Question

the high efficiency filter must be changed when (select all that apply):
at every holiday
the unit does not pass the air flow test with a properly charged battery
the low air flow alarm is activated
annually, or at the frequency recommended by site infection prevention
the filter has been physically damaged or is visibly soiled or contaminated

Explanation:

• "At every holiday" is not a valid reason for filter change (no clinical/technical basis).
• If the unit fails air flow test (proper battery), filter may be clogged, so change.
• Low air flow alarm activation implies reduced flow, filter issue.
• Annual or site - recommended frequency is standard for filter maintenance.
• Physical damage, soiling, or contamination of filter requires change.

Answer:

• The unit does not pass the air flow test with a properly charged battery
• The low air flow alarm is activated
• Annually, or at the frequency recommended by site Infection Prevention
• The filter has been physically damaged or is visibly soiled or contaminated