When central systems are used to air condition patients’
rooms, the recommendations in for air filtration and air
change rates should be followed to reduce crossinfection
and to control odor.
Rooms used for isolation of infected patients should have
all air exhausted directly outdoors.
A winter design temperature of 24°C with 30% rh is
recommended; 24°C with 50% rh is recommended for summer.
Each patient room should have individual temperature control.
Air pressure in patient suites should be neutral in relation
to other areas.
Most governmental design criteria and codes require that
all air from toilet rooms be exhausted directly outdoors.
The requirement appears to be based on odor control. Chaddock
(1986) analyzed odor from central (patient) toilet exhaust
systems of a hospital and found that large central exhaust
systems generally have sufficient dilution to render the
toilet exhaust practically odorless.
Where room unit systems are used, it is common practice
exhaust through the adjoining toilet room an amount of air
equal to the amount of outdoor air brought into the room
for ventilation. The ventilation of toilets, bedpan closets,
bathrooms, and all interior rooms should conform to applicable
codes. Intensive Care Units. These units serve seriously
from postoperative to coronary patients. A variable range
temperature capability of 24 to 27°C, a relative humidity
of 30% minimum and 60% maximum, and positive air pressure
are recommended. Protective Isolation Units. Immunosuppressed
patients (including bone marrow or organ transplant, leukemia,
burn, and AIDS patients) are highly susceptible to diseases.
Some physicians prefer an isolated laminar airflow unit
to protect the patient; others are of the opinion that the
conditions of the laminar cell have a psychologically harmful
effect on the patient and prefer flushing out the room and
reducing spores in the air. An air distribution of 15 air
changes per hour supplied through a nonaspirating diffuser
is often recommended.
The sterile air is drawn across the patient and returned
near the floor, at or near the door to the room. In cases
where the patient is immunosuppressed but not contagious,
a positive pressure should be maintained between the patient
room and adjacent area.
Some jurisdictions may require an anteroom,
which maintains a negative pressure relationship with respect
to the adjacent isolation room and an equal pressure relationship
with respect to the corridor, nurses’ station, or
common area. Exam and treatment rooms should be controlled
in the same manner. A positive pressure should also be maintained
between the entire unit and the adjacent areas to preserve