2006 OPEN FORUM Abstracts
Bench Examination of Pressure Distal to the Endotracheal Tube (ETT) While Suctioning the Neonate.
John S Emberger BS RRT, Joel Brown II
BS RRT,
Background: Both
closed and open suctioning are used in neonates. We
examined the pressure waveform on the distal (patient) side of the ETT for an
"actively breathing" neonatal bench model during suctioning.
Methods: A neonate lung model was
created simulating spontaneous breaths. The lung was enclosed in a container (Comp.=0.0018 L/cmH2O, Resist.=65
cmH2O/L/sec, Time Constant=0.117). Intermittent regulated vacuum was applied to
the container, creating reproducible inspirations. A spirometer (CO2SMOPlus, Respironics)
was placed distal to both the ETT and suction catheter position to capture the
pressure wave during suctioning. Vent settings: PIP=20 cmH2O, PEEP=5 cmH2O, Rate=26,
I-time=0.4 sec. A 3.0 ETT and #6 fr. suction
catheters were used. Four scenarios were examined: 1) Open Suctioning 2) Closed suctioning on Time Cycled Pressure
Limited (TCPL) ventilation (VIP, Bird Medical Systems) 3) Closed suctioning on Pressure Controlled
(PCV) ventilation (Evita 4, Draeger Medical)
4) Closed suctioning on Volume Targeted Pressure Limited (VTPL)
ventilation (Evita 4, Draeger Medical)
Results:
Pressures measured in the bench model distal to the ETT are displayed:
| Open Suctioning | Closed TCPL | Closed PCV | Closed VTPL | |
| Avg Pressure | - 6.0 cmH2O | 1.7 cmH2O | 1.2 cmH2O | 2.5 cmH2O |
| Min Pressure | -23.9 cmH2O | -18.1 cmH2O | -17.2 cmH2O | -14 cmH2O |
| Max Pressure | 6.2 cmH2O | 16.2 cmH2O | 18.7 cmH2O | 24.2 cmH2O |
Conclusion: Caregivers
expect pressure on the distal side of the ETT during open suctioning to be
lower than when closed suctioning is used. Our study shows that with standard
suction pressure and standard suction catheters, pressures distal to the ETT
can approach -25 cmH2O, and can average -6.0 during an open suctioning event.
We also found that average pressure distal to the ETT is not well preserved
even when performing closed suctioning with TCPL and PCV. In this neonatal bench model, the VTPL
preserved the distal airway pressure most effectively, yet distal pressure
still dropped as low as -14 cmH20 during a closed suctioning event.