Breathing Pressure Monitoring; Overview; Choice Of Breathing Pressure Monitoring Location - Dräger Narkomed 2B Operator's Instruction Manual

Overview

Choice of Breathing
Pressure Monitoring
Location
Breathing pressure is measured with a solid-state pressure transducer
that can sense pressure at either the absorber or patient Y-piece,
depending on which pilot line is used.
North American Dräger has no control over the type of breathing hoses
and Y-pieces that are ultimately used with NAD absorber systems and
pressure monitors—specifically, whether such user-supplied components
include a terminal for pressure monitoring at or near the Y-piece. In
order to ensure that some form of pressure monitoring is always used,
provisions have been made for pressure monitoring at the absorber (the
quick-connect fitting on the absorber gas pipe). However, do not construe
this provision for monitoring at the absorber as a recommendation from
North American Dräger for this pressure monitoring location.
In fact, arguments can be made for pressure monitoring at either the
Y-piece or at the absorber. Advocates of Y-piece pressure monitoring first
claim that it more accurately reflects the pressure developed in the
patient's lungs. They also claim that a blocked breathing system can be
more easily detected with this method when compared with pressure
monitoring at the absorber.
For example, if the inspiratory breathing hose became kinked or blocked
during automatic ventilation, the ventilator bellows would continue to
cycle against the blocked hose. A pressure monitor connected at the Y-
piece (downstream of the occlusion) could sense either an absence of
pressure fluctuation and alarm, or could sense a reduced pressure
fluctuation (below the threshold pressure alarm limit) and alarm. In
contrast, a pressure monitor connected at the absorber (upstream of the
occlusion) could sense a pressure fluctuation above the threshold
pressure alarm limit, and thus would not alarm. (Both of these scenarios
assume that the occlusion does not cause a peak pressure high enough to
activate the peak pressure alarm, which is meant to detect pressures
likely to cause barotrauma.)
However, North American Dräger disagrees with the idea of relying on
pressure monitoring to detect a blocked breathing circuit. Carbon dioxide
monitoring and respiratory flow monitoring provide superior detection of
blocked breathing paths when compared to pressure monitoring, which
detects such conditions only in some instances. North American Dräger
pressure monitors are therefore not promoted for detection of blocked
breathing paths.
Further, Y-piece pressure monitoring has several disadvantages that
could collectively cause the operator to neglect connecting the pressure
monitoring pilot line. Examples include increased contamination of the
pilot line due to its proximity to secretions, buildup of condensation
within the pilot line, and the introduction of additional disconnection
points (if the pilot line connects to a 15 mm adapter).
In conclusion, the responsibility for the selection of pressure monitoring
at either the absorber or the Y-piece rests with you, the operator. Your
Section 5 - Operation

Breathing Pressure Monitoring

5-12-1