Effect of Percutaneous Tracheostomy on Gas Exchange in Hypoxemic and Nonhypoxemic Mechanically Ventilated Patients

BACKGROUND: The influence of percutaneous tracheostomy on ventilator-dependency 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 intensive care unit (ICU) patients. METHODS: In this retrospective study, clinical records of 107 patients from a general ICU and neurosurgical ICU that underwent percutaneous tracheostomy were revised to compare ventilator setting, gas exchange and hemodynamics parameters on the day before and on the day after the procedure. Further, a pre-established subgroup analysis on hypoxemic patients (PaO₂/FiO₂<300 mmHg) was performed. RESULTS: Among all patients analyzed, a marginal decrease in PaCO₂ (43±9 vs. 42±7mmHg, 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 inPaO₂/FiO₂ (222 ± 60 vs. 256 ± 84mmHg, before vs. after P = .001) and a decrease in PaCO₂(46 ± 11 vs. 43 ± 9mmHg, before vs. after P =.001) were found. CONCLUSIONS: Percutaneous tracheostomy did not worsen gas exchange in a cohort of ICU patients. In hypoxemic patients, tracheotomy appeared to improve oxygenation and ventilation.