2006 OPEN FORUM Abstracts
OPEN VERSUS CLOSED SUCTION DELIVERY DURING HIGH FREQUENCY OSCILLATORY VENTILATION (HFOV)
Dennis Gaudet, RRT;
Matthew P. Branconnier, RRT, EMT; Dean R. Hess, PhD, RRT, FAARC.
Background: Because
the use of closed suction is not universally accepted during HFOV, it is the practice
of some clinicians to disconnect the patient from HFOV for open suctioning. Anecdotally,
we have noted fewer adverse clinical effects when closed suction, compared with
open suction, is used during HFOV. We conducted this bench study to evaluate
simulated tracheal pressure with open and closed suction during HFOV.
Method:
A calibrated Sensormedics 3100A with a flexible circuit was connected to a cuffless endotracheal tube (Mallincrodt),
the distal end of which was attached to a pressure sensor and Michigan
Instruments neonatal test lung in a leak-free manner. All combinations of the
following variables were evaluated: endotracheal tubes with internal diameters
of 2.5 and 3.5 mm; mean airway pressure of 15 and 25 cm H2O;
amplitude of 20 and 30 cm H2O; frequency of 10 and 14 Hz. A Ballard 6
French inline suction catheter with a 45o angle was used. Simulated
tracheal suction was performed with the oscillator attached to the endotracheal
tube (closed suction) or disconnected from the endotracheal tube (open
suction). Suction was applied at 80 mm Hg in a manner simulating the clinical
procedure. Data acquisition software (Analysis Plus) was used to record
pressure at 100 Hz from the distal endotracheal tube (Novametrix
NICO). For each set of variables, mean tracheal pressure and pressure amplitude
were measured at the distal endotracheal tube (simulated trachea). Three
representative breaths were analyzed.
Results:
There was a significant change in mean tracheal pressure (29 ± 9% decrease;
P < 0.001) and amplitude (64 ± 5% decrease; P < 0.001) when closed
suction was applied. The pressure at the simulated tracheal level was always
positive with closed suction. With open suction, the pressure at the simulated
tracheal level dropped quickly to atmospheric and was sub-atmospheric during
the application of suction (see figure). Also note that the time of interrupted
ventilation was less with closed suction.
Conclusions:
In this model of suctioning during HFOV, positive tracheal pressure was
maintained with closed suction, but not with open suction. This suggests that
closed suction may be preferable to open suction during HFOV. Because mean tracheal
pressure and amplitude decreased even with closed suction, suction duration of
should be minimized. Further work is needed to clinically validate these
results.
