Objective: To study the possibility of using continuous tracheal gas insufflation (CTGI) in dogs with spontaneous breathing.
Methods: Eight canine with oleic acid induced lung injury which had spontaneous breathing were ventilated by Evita 2 (Drager Inc). The setting parameters were FiO(2) (60%), I/E (1:1), RR (20) and PEEP (5 cm H(2)O) in four different conditions: BIPAP (BIPAP group) and BIPAP with different CTGI flow rates (3, 6 and 9 L/min, T3, T6 and T9 group). Gas exchange, lung mechanics and hemodynamic status were monitored at the same level of PaCO(2) obtained by adjusting the high pressure (P high) of BIPAP.
Results: The peak inspiratory pressures in the T6 group (14 cm H(2)O +/- 4 cm H(2)O) and T9 group (11 cm H(2)O +/- 3 cm H(2)O) were significantly lower than that of BIPAP group (20 cm H(2)O +/- 5 cm H(2)O, P < 0.01), but significant differences were not found neither among T3, T6 and T9 groups, nor between T3 and BIPAP groups. PaO(2), hemodynamics and oxygenation remained unchanged in the four different conditions.
Conclusion: BIPAP combined with CTGI in canine with spontaneous breathing could significantly decrease the airway pressure, with no influence on hemodynamics and oxygenation. Thus BIPAP with CTGI may be a useful support technique, especially for cases whose airway pressure should be limited.