Specifications

29
Respiratory Cycle The period of time from the beginning of one inspiration to the
beginning of the next inspiration.
S Spontaneous mode. The patient triggers all movement from the EPAP to
the IPAP level. Movement from the IPAP to the EPAP level is caused by
the Spontaneous Expiratory Threshold, by patient effort, or by the
maximum spontaneous IPAP time limit.
Spontaneous Resulting from patient effort. The patient initiates inspiration and
establishes the frequency of breathing. Also see “S.”
Spontaneous Trigger For spontaneous breaths in the S and S/T modes, movement to IPAP is
triggered by an increase in the Estimated Flow Rate (V
est
) that exceeds
the Estimated Leak Flow Rate (V
leak
) by 47.5 cc/sec for approximately 30
msec.
S/T Spontaneous mode with Timed backup. The minimum frequency of
movement to IPAP is predetermined by the BPM control, however, the
patient has the option of initiating inspiration at a faster rate. Movement
from the IPAP to the EPAP level is triggered by the Spontaneous
Expiratory threshold, by patient effort, or by the integrated maximum
spontaneous IPAP time limit.
T Timed mode. The frequency of cycling is determined by the BiPAP unit,
according to a preset pattern. All movement from EPAP to IPAP is
controlled by the BPM timer. All movement from IPAP to EPAP is
controlled by the % IPAP control.
Tidal Volume That volume of air that is either inhaled or exhaled with each breath
during quiet breathing.
Total Flow Rate All flow through the blower outlet is continuously measured by an
internal flow transducer that is in series with the blower outlet. This flow
is composed of the continuous flow present due to leaks and the
instantaneous flow that occurs during patient tidal breathing. These
combined flows are referred to as the Total Flow Rate (V
tot
).
Unintentional Leak Component of the Estimated Leak Flow Rate (V
leak
) caused by flow
around the mask or other patient circuit leaks.
V Flow, which is volume per unit of time (i.e., L/min.) .
V
leak
The Total Flow Rate is analyzed to determine what portion of the flow
through the circuit is due to intentional (Whisper Swivel II or
Respironics Disposable Exhalation Port) and unintentional (mask fit)
leaks. The continuous unintentional leak level is referred to as the
Estimated Leak Flow Rate (V
leak
). The V
leak
is a calculated component of
V
tot
composed of intentional and unintentional leaks.
VT
E
Expiratory Tidal Volume.
VT
I
Inspiratory Tidal Volume Specifications.
Abbreviations/Definitions
Threshold