GE CARESCAPE, User Manual

Page: 329 / 548

Patient Spirometry
D-lite(+)/Pedi-lite(+) flow sensor
1. For total pressure measurement
2. For static pressure measurement
3. For gas samples
The velocity of gas flow is obtained when the dynamic pressure is measured by the
two hollow tubes (1 and 2). On inspiration, gas moves from the anesthesia machine or
ventilator to the patient by point 1 which measures the total pressure, and at the same
time the pressure at tube 2 is measured as the static pressure. The static pressure at
2 is subtracted from the total pressure at 1 to give the dynamic pressure. Dynamic
pressure is proportional to the velocity of gas flow. D-lite(+)/Pedi-lite(+) is designed to
work in both directions; during expiration the process is reversed. Gas samples for
CO
2
, O
2
, N
2
O and anesthetic agent measurements are taken through port 3.
One end of the sensor has a 15 mm male connector for a Y-piece connection, while
the patient end consists of a 22 mm male connector for the ventilation mask and
a concentric 15 mm female connector for the endotracheal tube. A disposable
double-lumen tube conducts the flow signal as a pressure difference to the pressure
sensor inside the monitor. This measurement method means that there is no gas flow
in the double-lumen tube, but only pressure pick-up. A respiratory gas sampling line
connected to the D-lite(+)/Pedi-lite(+) completes the monitoring system. Gas sampling
is important to enable compensation of the effect of different gas viscosities on tidal
and minute volume calculations.
Patient Spirometry parameters
Measured Patient Spirometry parameters are the following:
●
Inspiratory and expiratory tidal volumes (TVinsp/exp)
●
Inspiratory and expiratory minute volumes (MVinsp/exp)
●
Airway pressures
●
Peak pressure (Ppeak): maximum pressure during one breath
●
Plateau pressure (Pplat): pressure at the reversal point of the flow
●
Mean pressure (Pmean): average pressure during one breath
●
Real-time pressure waveform (Paw)
●
Positive end expiratory pressure (PEEPtot) in OR and PACU software packages only:
the pressure in the lungs at the end of expiration, measured when expiratory phase
changes to inspiratory flow.
●
Extrinsic positive end expiratory pressure (PEEPe) and intrinsic positive end
expiratory pressure (PEEPi) (not in OR and PACU software packages).
●
Compliance (Compl): calculated for each breath, indicates the pressure difference
required to deliver a certain volume of gas into the patient.
2062971-001 CARESCAPE Modular Monitors 329