Asymmetrical high-flow nasal cannula performs similarly to standard interface in patients with acute hypoxemic post-extubation respiratory failure: a pilot study

Table 2 Electrical impedance tomography parameters

Variable	Standard HFNC^a (N = 20)	Asymmetrical HFNC^b (N = 20)	Adjusted p-value (a-b)	Venturi mask^c (n = 20)	Adjusted p-value (b-c)
MV (change from VM), %	−13 [−26, 1]	−12 [−18, −2]	0.731	–	0.145*
Corrected MV (change from VM), %	−10 [−21, 3]	−11 [−19, −0.10]	0.992	–	0.050*
Global V_T, (change from VM), %	106 [87–130]	100 [94–113]	0.654	–	0.749
V_{T non−dep}, %	57 [31–66]	58 [41–66]	0.731	53 [42–60]	0.749
V_{T dep}, %	51 [37–68]	51 [39–57]	0.731	48 [41–59]	0.936
Ratio V_{T non−dep/dep}	1.04 [0.60–1.49]	1.12 [0.71–1.53]	0.843	1.10 [0.80–1.50]	0.749
GI index	48 [38–51]	49 [45–65]	0.654	49 [42–73]	0.749
Global RVD, %	11 [8–17]	12 [8–18]	0.336	11 [7–16]	0.936
RVD _non−dep, %	14 [11–20]	14 [9–24]	0.336	13 [9–21]	0.749
RVD _dep, %	9 [6–13]	9 [7–13]	0.654	9 [6–11]	0.936

Variables are expressed as median, with an interquartile range [IQR]. *p-value a-c: 0.018 and 0.006, respectively. a = Standard HFNC; b = Asymmetrical HFNC; c = Venturi mask
Abbreviations: HFNC high-flow nasal cannula, DE diaphragmatic excursion, TFdi diaphragmatic thickening fraction, VT tidal volume, dep dependent, non-dep non-dependent, EELI delta end-expiratory lung impedance (measured as percent change from Venturi mask), GI global inhomogeneity index, RVD regional ventilation delay, MV minute ventilation, VM Venturi mask, N number

ISSN: 1471-2466