Philips M3015A - Page 74

Mainstream CO
2
Measurement
58
Introduction to the Instrument
• O
2
Correction— There is a fixed correction of 45% O
2
.
• Humidity Correction—This correction is selectable between Body Temperature Pressure
Saturated (BTPS) and Standard Pressure Temperature Dry (STPD). The Extension meas-
ures BTPS and uses this correction formula:
where P
H20
= 47mmHg
• Max Hold—There are three possible selections:
• Off—The EtCO
2
numerics display the breath-to-breath value.
• 10 seconds—The EtCO
2
numerics display the highest value within a moving window
over a 10-second period.
• 20 seconds—The EtCO
2
numerics display the highest value within a moving window
over a 20-second period.
Safety
To ensure the safety of the patient, the patient-applied part is isolated from ground by opto-
couplers and a transformer. The circuit is also encapsulated in plastic.
P
STPD
= P
BTPS .
P
abs
P
abs
–P
H2O