PT - JOURNAL ARTICLE AU - Augusto Savi AU - Juçara Gasparetto Maccari AU - Túlio Frederico Tonietto AU - Ana Carolina Peçanha Antonio AU - Roselaine Pinheiro de Oliveira AU - Marcelo de Mello Rieder AU - Evelyn Cristina Zignani AU - Émerson Boschi da Silva AU - Cassiano Teixeira TI - Influence of F<sub>IO<sub>2</sub></sub> on P<sub>aCO<sub>2</sub></sub> During Noninvasive Ventilation in Patients With COPD AID - 10.4187/respcare.02816 DP - 2014 Mar 01 TA - Respiratory Care PG - 383--387 VI - 59 IP - 3 4099 - http://rc.rcjournal.com/content/59/3/383.short 4100 - http://rc.rcjournal.com/content/59/3/383.full AB - BACKGROUND: The administration of a high FIO2 to COPD patients breathing spontaneously may result in hypercapnia, due to reversal of preexisting regional hypoxic pulmonary vasoconstriction, resulting in a greater dead space. Arterial blood gas trends have not been reported in these patients. In a 31-bed medical ICU in a teaching hospital we prospectively investigated the response of 17 CO2-retaining COPD patients, after acute respiratory crisis stabilization with noninvasive ventilation, to an FIO2 of 1.0 for 40 min, after having been noninvasively ventilated with an FIO2 of ≤ 0.50 for 40 min. RESULTS: The mean ± SD baseline findings were: PaO2 101.4 ± 21.7 mm Hg, PaCO2 52.6 ± 10.4 mm Hg, breathing frequency 17.8 ± 3.7 breaths/min, tidal volume 601 ± 8 mL, and Glasgow coma score of 14.8 ± 0.3. PaO2 significantly increased (P &lt; .001) when FIO2 was increased to 1.0, but there was no significant change in PaCO2, breathing frequency, tidal volume, or Glasgow coma score. CONCLUSIONS: During noninvasive ventilation with an FIO2 sufficient to maintain a normal PaO2, a further increase in FIO2 did not increase PaCO2 in our CO2-retaining COPD patients.