3.
Temperature Gradient
(only active if using heated-wire circuits)
When using the ConchaTherm Neptune with heated-wire circuits, the temperature gradient
may be adjusted to allow for the proximal patient airway temperature to be up to 3.0 ºC
warmer or cooler than the temperature at the column outlet. Adjustment of the temperature
gradient allows for better control of condensation or “rainout” within the circuit. A positive
temperature gradient results in an airway temperature that is warmer than the temperature of
the gas at the column. A negative temperature gradient results in an airway temperature that
is cooler than the temperature of the gas at the column. This column-to-patient temperature
gradient is displayed as a blue LED when viewing the “set” parameters.
The ConchaTherm Neptune will arrive from the factory with the column-to-patient tempera-
ture gradient set at 0 ºC. A temperature gradient of 0 ºC allows the temperature of the gas,
and therefore, the relative humidity (RH) of the gas, to be constant throughout the length of
the heated-wire circuit. Figure 9 shows a typical circuit response and LED display when the
airway temperature is set at 37 ºC and the temperature gradient is set at 0 ºC.
To view the set temperature gradient
, quickly press and release the accept button.
The temperature gradient the will be displayed for five seconds and will be
represented by a the blue LED between the Sun and Raindrop.
To adjust the temperature gradient
, press and hold the accept button. The zero
temperature gradient icon , the blue temperature gradient LED, and the sun
and rain icons will be illuminated.
To set a more positive temperature gradient
, press the sun button for each
additional positive degree desired.
Note:
A positive or increased temperature gradient results in a lower relative humidity
( RH) at the proximal patient airway and potentially less rainout in the circuit tubing.
Important:
A positive temperature gradient may result in a humidity deficit to the patient,
depending on the temperatures and ventilator parameters used.
21
Figure 9: Zero Temperature Gradient, Display at 0°C.
Figure 10: Positive Temperature Gradient, Display at +3.0°C.
