21-16 DELTA/DELTA XL/KAPPA VF8
21 R
ESPIRATORY MECHANICS
Respiratory Mechanics Parameters
The following table lists respiratory mechanics parameters, derivations, and units of
measure.
NOTE:
Spontaneous (s) and mechanical (m) rates and volumes are calculated
separately and are designated by the letters <s> or <m> after the parameter (for
example, MVe s for expired Minute Volume, spontaneous ventilation; MVe m
for expired Minute Volume, mechanical ventilation).
Resistance and compliance are not calculated in spontaneously breathing
patients. The resistance and compliance values displayed for spontaneous
breaths are zero.
For the purposes of compensation, the temperature of the breathing circuit is
assumed to be 35 °C for inspired and expired gas; the humidity of the breathing
circuit is assumed to be 50 % for inspired gas and 100 % for expired gas; and
the default gas composition values are 21 % O
2
and 0 % CO
2
for inspiratory
and 17 % and 5 % CO
2
for expiratory (only VCO2 and TVCO2 are referenced
to STPD, or standard temperature pressure dry). Therefore, TVi will, in most
cases, be equal to or greater than TVe.
Label Description Derivation Units
C20/
Cdyn
C
2
0 / Cdyn Ratio
(mechanical)
Ratio of the compliance of the last 20 % of
inspiration over dynamic lung compliance
(available only when neonatal sensor is used)
Cdyn Lung Compliance,
Dynamic (mechanical)
Ratio of change in volume over change in pressure
during inspiration
mL/
cmH
2
O
I:E Ratio of Inspiratory to
Expiratory Time
Ratio of inspiratory time to expiratory time, using
all the breaths and updated on a breath by breath
basis
InspT
%
Percent Inspired Time Ratio of inspiratory time to total time of breath x
100 %
%
MAP Mean Airway Pressure Average airway pressure measured during entire
breath cycle
cmH
2
O
MValv Alveolar Minute Volume Average alveolar volume per minute of effective
gas exchange
L
MVe Expired Minute Volume Average expired volume per minute, calculated
using an eight breath moving average
L/min
Pause Pause Pressure
(mechanical)
Airway pressure held during an inspiratory pause;
calculated only in mechanical breaths
cmH
2
O
PeCO2 Mixed Expired CO2 Volume of CO
2
in a breath divided by the eight
breath moving average of total expired volume
mmHg
PEEP Positive End-Expiratory
Pressure
Lowest positive airway pressure at end of
expiratory period or average airway pressure
during last 25 % of expired flow
cmH
2
O
To Next Page
Loading...
