Efficacy of continuous tracheal gas insufflation in spontaneously breathing canine with acute lung injury.
OBJECTIVE
To investigate the effects of continuous tracheal gas insufflation (CTGI) combined with biphasic intermittent positive airway pressure (BIPAP) ventilation on dogs with spontaneous breathing.


METHODS
Eight canine models with oleic acid induced lung injury and spontaneous breathing were ventilated in a random order by Evita 2 (Drager Inc., Germany) in modes of BIPAP (BIPAP group) and BIPAP with CTGI flow rate of 3, 6 and 9 L/min (T3, T6 and T9 groups), respectively. The setting parameters of BIPAP were fiction of inspired oxygen 60%, inspiratory to expiratory ratio 1:1, respiratory rate 20 and positive end expiratory pressure 5 cm H2O. Arterial and mixed venous blood gas, lung mechanics, systemic and pulmonary hemodynamics status were monitored at the same level of PaCO2 obtained by adjusting peak inspiratory pressure of BIPAP.


RESULTS
Peak inspiratory pressure in the T6 group (14 +/- 4 cm H2O) and in the T9 group (11 +/- 3 cm H2O) were significantly lower than that of BIPAP (20 +/- 5 cm H2O, P < 0.01), but there was no significant difference among the T3, T6 and T9 groups or between the T3 and BIPAP groups. PaO2, mean artery blood pressure, mean pulmonary artery pressure, pulmonary artery wedge pressure, cardiac output, oxygen delivery and oxygen consumption all remained unchanged in four different conditions.


CONCLUSIONS
Using BIPAP combined with CTGI does not cause asynchrony between ventilator and spontaneous breathing, but significantly decreases airway pressure with no influence on hemodynamics and oxygenation. Therefore, BIPAP with CTGI may be a useful support technique, especially in cases where the airway pressure should be limited.
Zhan
Q
Q
Beijing Institute of Respiratory Medicine, Beijing Chaoyang Hospital, Capital University of Medical Sciences, Beijing 100020, China.
Wang
C
C
Shang
M
M
Tong
Z
Z
Weng
X
X
D000818:Animals; D004285:Dogs; D007327:Insufflation / Q000379:methods*; D007384:Intermittent Positive-Pressure Breathing; D008168:Lung / Q000473:pathology / Q000503:physiopathology*; D010366:Peak Expiratory Flow Rate / Q000502:physiology; D011175:Positive-Pressure Respiration; D011659:Pulmonary Gas Exchange / Q000502:physiology; D015656:Respiratory Mechanics / Q000502:physiology; D016896:Treatment Outcome; D015300:Ventilator Weaning / Q000379:methods*