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Table 2 Breathing pattern and gas exchange in different experimental conditions

From: High-flow nasal cannula oxygen therapy decreases postextubation neuroventilatory drive and work of breathing in patients with chronic obstructive pulmonary disease

  HFNC1 Conventional O2 HFNC2
RR (breaths/min) 20.5 ± 2.9 21.4 ± 4 20.0 ± 1.9
TiNEUR (s) 0.92 ± 0.21 0.95 ± 0.22 0.92 ± 0.17
pH 7.45 ± 0.07 7.44 ± 0.08 7.46 ± 0.08
PaCO2 (mmHg) 49.9 ± 11.9 51.8 ± 12.7 50.1 ± 12.6
HCO3 (mEq/L) 30.9 ± 7.6 31.3 ± 7.8 31.4 ± 8.4
PaO2 (mmHg) 75.1 ± 6.9 72.9 ± 8.6 81.2 ± 8
Applied FiO2a 0.46 ± 10 0.80 ± 0.19b,c 0.46 ± 0.12
  1. Data are expressed as mean ± standard deviation
  2. Conventional O2 conventional low flow oxygen therapy through a nonocclusive face mask, FiO2 inspiratory oxygen fraction, HFNC high-flow nasal cannula oxygen therapy, PaCO2 arterial partial carbon dioxide pressure, PaO2 arterial partial oxygen pressure, RR respiratory rate, TiNEUR neural inspiratory time
  3. a The FiO2 delivered during conventional O2 therapy is overestimated since the patient’s inspiratory flow was higher than the mask flow (10 L/min) and, therefore, the difference between patient inspiratory flow and mask flow was taken by room air; this makes inappropriate any comparison between the PaO2/FiO2 ratio in the different experimental conditions
  4. b Different from HFNC1, ANOVA, with Bonferroni correction
  5. c Different from HFNC2, ANOVA, with Bonferroni correction