Open-lung protective ventilation with pressure control ventilation, high-frequency oscillation, and intratracheal pulmonary ventilation results in similar gas exchange, hemodynamics, and lung mechanics.
BACKGROUND
Pressure control ventilation (PCV), high-frequency oscillation (HFO), and intratracheal pulmonary ventilation (ITPV) may all be used to provide lung protective ventilation in acute respiratory distress syndrome, but the specific approach that is optimal remains controversial.


METHODS
Saline lavage was used to produce acute respiratory distress syndrome in 21 sheep randomly assigned to receive PCV, HFO, or ITPV as follows: positive end-expiratory pressure (PCV and ITPV) and mean airway pressure (HFO) were set in a pressure-decreasing manner after lung recruitment that achieved a ratio of Pao2/Fio2 > 400 mmHg. Respiratory rates were 30 breaths/min, 120 breaths/min, and 8 Hz, respectively, for PCV, ITPV, and HFO. Eucapnia was targeted with peak carinal pressure of no more than 35 cm H2O. Animals were then ventilated for 4 h.


RESULTS
There were no differences among groups in gas exchange, lung mechanics, or hemodynamics. Tidal volume (PCV, 8.9 +/- 2.1 ml/kg; ITPV, 2.7 +/- 0.8 ml/kg; HFO, approximately 2.0 ml/kg) and peak carinal pressure (PCV, 30.6 +/- 2.6 cm H2O; ITPV, 22.3 +/- 4.8 cm H2O; HFO, approximately 24.3 cm H2O) were higher in PCV. Pilot histologic data showed greater interstitial hemorrhage and alveolar septal expansion in PCV than in HFO or ITPV.


CONCLUSIONS
These data indicate that HFO, ITPV, and PCV when applied with an open-lung protective ventilatory strategy results in the same gas exchange, lung mechanics, and hemodynamic response, but pilot data indicate that lung injury may be greater with PCV.
Sedeek
Khaled A
KA
Department of Anesthesia/Respiratory Care, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA.
Takeuchi
Muneyuki
M
Suchodolski
Klaudiusz
K
Vargas
Sara O
SO
Shimaoka
Motomu
M
Schnitzer
Jay J
JJ
Kacmarek
Robert M
RM
D000399:Air Pressure; D000465:Algorithms; D000818:Animals; D005122:Exudates and Transudates / Q000378:metabolism; D006098:Granulocytes / Q000502:physiology; D006439:Hemodynamics / Q000502:physiology*; D006470:Hemorrhage / Q000209:etiology / Q000503:physiopathology; D006612:High-Frequency Ventilation; D007375:Interleukin-1 / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism; D007442:Intubation, Intratracheal; D008168:Lung / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D010366:Peak Expiratory Flow Rate; D011650:Pulmonary Alveoli / Q000502:physiology; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D012121:Respiration, Artificial / Q000295:instrumentation / Q000379:methods*; D015656:Respiratory Mechanics / Q000502:physiology*; D012756:Sheep; D013990:Tidal Volume / Q000502:physiology
D007375:Interleukin-1; D016209:Interleukin-8; D010100:Oxygen