Sustained oxygenation without ventilation in paralyzed pigs with high-flow tracheal oxygen.
OBJECTIVE
It is generally assumed that ventilation is necessary for oxygenation. This study tested if paralyzed animals without respirations can maintain arterial oxygenation when administered high-flow oxygen delivered by a catheter in the trachea.


METHODS



METHODS
Prospective observational study.


METHODS
University research laboratory.


METHODS
3 anesthetized/paralyzed swine weighing 29.5 +/- 4.2 kg. INTERVENTIONS/OBSERVATIONS: Pigs were intubated, anesthetized with intravenous tiletamine and a pentobarbital drip. A femoral arterial line was placed to record arterial blood gases and vital signs every 5 minutes. Respiratory paralysis was obtained with vecuronium 150 microg/kg and repeated at any sign of movement. A catheter was placed in the trachea to deliver oxygen at 15 L/min. Outflow gas from the endotracheal tube was analyzed for O2 and CO2. O2 was discontinued at 75 minutes. The institutional animal care and use committee approved the protocol.


RESULTS
All pigs survived to 75 minutes. PaO2 was more than 100 mm Hg throughout the study period. Mean PaCO2 was 37.4 +/- 2.8 mm Hg at baseline, 146 +/- 59 at 30 minutes, then rose above 200 mm Hg in all pigs by 45 minutes. Mean arterial pH fell from 7.47 +/- 0.04 at onset to 6.75 +/- 0.06 at 75 minutes. When oxygen was terminated at 75 minutes, PaO2 fell to 16.5 +/- 7.6 mm Hg within 5 minutes, and all pigs were sacrificed within 10 minutes. For outflow gas, O2 was more than 98% and expired CO2 less than 1% throughout the study period.


CONCLUSIONS
Paralyzed, unventilated pigs receiving high-flow oxygen via a tracheal catheter remained alive after 75 minutes, although a profound respiratory acidosis developed.
Meggs
William J
WJ
Department of Emergency Medicine, Brody School of Medicine at East Carolina University, Greenville, NC 27858, USA. meggsw@mail.ecu.edu
Carroll
Robert G
RG
Brewer
Kori L
KL
Hack
Jason B
JB
Reeder
Timothy J
TJ
D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D004195:Disease Models, Animal; D006339:Heart Rate / Q000502:physiology; D010100:Oxygen / Q000008:administration & dosage*; D010101:Oxygen Consumption / Q000502:physiology*; D010102:Oxygen Inhalation Therapy / Q000379:methods*; D010865:Pilot Projects; D012133:Respiratory Paralysis / Q000378:metabolism* / Q000503:physiopathology / Q000628:therapy*; D013552:Swine; D013997:Time Factors
D010100:Oxygen