Effect of percutaneous tracheostomy on gas exchange in hypoxemic and non-hypoxemic mechanically ventilated patients

BACKGROUND: The influence of percutaneous tracheostomy on ventilator-dependence and clinical outcomes has been investigated in a number of studies. However, except for the variations during the procedure, the impact of tracheostomy on gas exchange has been scarcely explored. We investigated the effect of tracheostomy on respiratory function in a cohort of ICU patients. METHODS: In this retrospective study, clinical records of 107 patients from a general ICU and neurosurgical ICU who underwent percutaneous tracheostomy were reviewed to compare ventilator setting, gas exchange, and hemodynamic parameters on the day before and on the day after the procedure. Further, a pre-established subgroup analysis on hypoxemic patients (PaO2/FIO2 < 300 mm Hg) was performed. RESULTS: Among all patients analyzed, a marginal decrease in PaCO2 (43 +/- 9 mm Hg vs 42 +/- 7 mm Hg, before vs after P = .004) and an increase in pH (7.43 +/- 0.04 vs 7.44 +/- 0.03, before vs after P = .03) were observed after tracheostomy. In the subgroup of hypoxemic patients (n = 38), after the tracheostomy an increase in PaO2/FIO2 (222 +/- 60 mm Hg vs 256 +/- 84 mm Hg, before vs after P = .001) and a decrease in PaCO2 (46 +/- 11 mm Hg vs 43 +/- 9 mm Hg, before vs after P = .001) were found. CONCLUSIONS: Percutaneous tracheostomy did not worsen gas exchange in a cohort of ICU patients. In hypoxemic patients, tracheostomy appeared to improve oxygenation and ventilation.