Objective: To test the effect of tracheal gas insufflation - TGI - on exchange of blood gases (in particular PaCO2) in children with severe respiratory failure. Type of study: Prospective observational study. Site: ARO and ECMO centre of Paediatric Faculty Hospital Brno. Patients: Eight children with acute hypoxaemic respiratory failure and marked hypercapnia. Methods: The patients were connected to a PCV or PRVC regime, oxygenation was optimalised by increasing the mean airway pressure (Paw) by increasing PEEP with a limited peak pressure (PIP) and the lowest necessary FiO2. They were ventilated by tidal volumes < 10 ml/kg, the minute ventilation was increased by the respiratory rate (RR). When PaCO2 < 10.0 kPa and/or pH < 7.20 was achieved, the authors introduced continuous tracheal gas insufflation, the gas flow through the catheter was between 150 and 200 ml/kg/min. Values of pH, PaO2, PaCO2, PaO2 /FiO2, the oxygenation index and ventilation index were recorded. Using the paired t-test, the mean values of parameters at time 0 and during the third hour of TGI were evaluated. Results: Within 3 hours of TGI the pH rose from 7.25 to 7.42 (p = 0.0002), PaCO2 dropped from 10.58 to 4.79 kPa (p < 0.0001) and the ventilation index from 76.3 to 33.9 (p < 0.002). Changes of PaO 2, PaO2 /FiO2 and OI are not statistically significant. Conclusion: TGI eliminates effectively CO2, improves alveolar ventilation and has no effect on oxygenation. It is a suitable therapeutic supplement of conventional mechanical ventilation of patients with severe respiratory failure with hypercapnia.

        Key words: tracheal gas insufflation, respiratory failure, CO2 elimination, children