A comparison of the effectiveness of open and closed endotracheal suction.
OBJECTIVE
To compare the effectiveness of open and closed endotracheal suction in recovering thin and thick secretions in normal and injured lungs during conventional and high frequency ventilation.


METHODS
Randomised study in a paediatric intensive care model in the animal research laboratory of a tertiary paediatric hospital.


METHODS
16 New Zealand White rabbits.


METHODS
Anaesthetised animals were intubated with a 3.5-mm endotracheal tube. Simulated thin and thick secretions (iopamidol 2 ml, a watery radio-opaque fluid, and fluorescent mucin 1 ml) were instilled in turn 1 cm below the tube tip through a catheter placed via a tracheostomy. Open or closed suction, randomly assigned, was applied for 6s at -140 mmHg using a 6-F gauge catheter. Following lung injury with repeated saline lavage the procedure was repeated on conventional and high frequency ventilation.


RESULTS
Iopamidol recovery was determined by digitally subtracting the post-contrast and post-suction radiographic images. Mucin recovery was determined by fluorescence assay of the aspirate. In the normal lung similar amounts were recovered by both suction methods. In the lavaged lung closed suction recovered less iopamidol during conventional (22 +/- 7.5%) and high frequency ventilation (11 +/- 2.4%) than open suction (36 +/- 2% and 22 +/- 8.1%, respectively). Mucin recovery was less with closed suction during conventional 32 +/- 28 microl) and high frequency ventilation (30 +/- 31 microl) than with open suction (382 +/- 235 microl and 24 +/- 153 microl).


CONCLUSIONS
In the injured lung closed suction was less effective than open suction at recovering thin and thick simulated secretions, irrespective of ventilation mode.
Copnell
Beverley
B
Royal Children's Hospital, Department of Neonatology, Flemington Rd, VIC 3052, Parkville, Australia. bev.copnell@rch.org.au
Tingay
David G
DG
Kiraly
Nicholas J
NJ
Sourial
Magdy
M
Gordon
Michael J
MJ
Mills
John F
JF
Morley
Colin J
CJ
Dargaville
Peter A
PA
D000818:Animals; D003287:Contrast Media / Q000008:administration & dosage / Q000302:isolation & purification; D003422:Critical Care; D005471:Fluoroscopy; D007442:Intubation, Intratracheal / Q000379:methods; D007479:Iopamidol / Q000008:administration & dosage / Q000302:isolation & purification; D008168:Lung / Q000000981:diagnostic imaging*; D055370:Lung Injury; D023421:Models, Animal; D009077:Mucins / Q000032:analysis; D011817:Rabbits; D011897:Random Allocation; D012121:Respiration, Artificial; D013396:Suction / Q000379:methods*; D007507:Therapeutic Irrigation
D003287:Contrast Media; D009077:Mucins; D007479:Iopamidol