Figures
- FIGURE 1
Comparative effects between high-flow nasal cannula (HFNC) and noninvasive ventilation (NIV) on global and regional tidal volume (VT) variation in all patients (n=16). Analysis of VT variation between HFNC and NIV in a) global lung, b) region of interest (ROI)1, c) ROI2, d) ROI3, e) ROI4, f) consolidation area. Data points represent VT values for individual patients with HFNC and NIV, and the horizontal line represents the median value. *: p<0.05 by Wilcoxon's test for dependent variable.
Tables
- TABLE 1
Patient characteristics and outcome data
Patients Age (years) Sex BMI (kg·m−2) SAPSII SOFA Localisation of lung consolidation (ROI1, 2, 3 or 4) Delay between admission and inclusion (days) Intubation ICU length of stay (days) Death 1 63 M 25 27 4 3 0 N 6 N 2 22 F 28 25 3 4 3 N 5 N 3 38 M 22 22 4 2 4 N 6 N 4 19 M 17 15 2 1 6 N 10 N 5 55 M 33 31 3 1 3 N 2 N 6 53 M 40 56 9 3 15 N 17 N 7 71 M 26 27 1 3 2 N 3 N 8 86 M 25 47 4 1 2 N 7 N 9 46 F 36 16 3 3 6 N 5 N 10 42 M 21 32 1 4 2 N 6 N 11 27 M 23 12 6 1 2 N 2 N 12 54 F 21 21 5 3 2 Y 17 Y 13 47 F 21 28 2 4 3 N 4 N 14 69 F 22 48 9 3 9 Y 23 N 15 56 F 26 33 2 3 3 N 6 N 16 33 F 46 20 2 4 4 N 5 N Total or median (IQR) 50 (37–58) 7 F
9 M25 (22–29) 27 (21–32) 3 (2–4) 4 ROI1
1 ROI2
7 ROI3
4 ROI43 (2–5) 2 Y
14 N6 (5–8) 1 Y
15 NBMI: body mass index; SAPSII: Simplified Acute Physiology Score II; SOFA: Sepsis-related Organ Failure Assessment; ROI: region of interest; ICU: intensive care unit; IQR: interquartile range; M: male; F: female; Y: yes; N: no.
- TABLE 2
Comparison between physiological effects of noninvasive ventilation (NIV) and high-flow nasal cannula (HFNC)
NIV HFNC HFNC–NIV Median (IQR) Median (IQR) Median (95% CI) p-value# VT global (units) 3161 (1884–3805) 2323 (1497–2891) −678.0 (−947.5– −322.0) 0.001 VT ROI1 (units) 887 (657–1033) 590 (464–774) −204.5 (−279.5– −122.0) 0.0007 VT ROI2 (units) 686 (413–925) 445 (262–656) −214.0 (−309.0– −130.0) 0.0003 VT ROI3 (units) 743 (498–1008) 589 (271–909) −118.5 (−221.5–0.0) 0.04 VT ROI4 (units) 444 (318–861) 450 (286–664) −93.5 (−200.0–7.5) 0.06 VT consolidation (units) 778 (338–1002) 489 (198–783) −133.0 (−215.0– −53.5) 0.004 EELI global (units) 4083 (2928–5134) 2921 (1706–4850) −570.5 (−1649.5–824.0) 0.4 EELI ROI1 (units) 842 (646–1144) 562 (215–1000) −329.0 (−570.5– −110.0) 0.01 EELI ROI2 (units) 960 (469–1406) 408 (355–1152) −174.0 (−563.0–79.5) 0.1 EELI ROI3 (units) 767 (336–1124) 618 (370–1251) −101.0 (−487.0–476.0) 0.5 EELI ROI4 (units) 846 (488–971) 447 (373–738) −196.0 (−491.5–733.0) 0.4 EELI consolidation (units) 899 (767–1144) 486 (381–946) −322.5 (−588.5–178.5) 0.1 Respiratory rate (breaths·min−1) 24 (22–27) 23 (21–26) −2 (−4–4) 0.6 SpO2/FiO2 ratio 167 (143–200) 163 (140–200) −4.5 (−15.5– −2.0) 0.001 SpO2 (%) 100 (98–100) 97 (96–100) −2 (−3–0) 0.010 Heart rate (beats·min−1) 84 (68–98) 90 (78–104) 1 (−2–5) 0.8 SBP (mmHg) 119 (108–131) 125 (113–137) 3 (−1–11) 0.2 MAP (mmHg) 80 (76–89) 85 (77–94) 2 (−3–5) 0.6 Dyspnoea score (0–10) 5 (0–5) 5 (2–5) 0 (−1–1) 0.7 Patient comfort score (0–10) 4 (2–5) 5 (4–7) 0 (−1–4) 0.7 Bold type represents statistical significance. IQR: interquartile range; VT: tidal volume variation; ROI: region of interest; EELI: end-expiratory lung impedance; SpO2: pulse oxygen saturation; FiO2: inspiratory oxygen fraction; SBP: systolic blood pressure; MAP: mean arterial pressure. #: Wilcoxon signed rank test.
- TABLE 3
Comparison between physiological effects of face mask (FM) and high-flow nasal cannula (HFNC)
FM HFNC HFNC–FM Median (IQR) Median (IQR) Median (95% CI) p-value# VT global (units) 2240 (1421–2752) 2323 (1497–2891) −3.0 (−138.5–153.5) 0.9 VT ROI1 (units) 618 (440–692) 590 (464–774) −30.0 (−96.0–35.0) 0.3 VT ROI2 (units) 408 (295–703) 445 (262–656) −18.5 (−63.5–37.0) 0.4 VT ROI3 (units) 597 (287–816) 589 (271–909) 14.5 (−27.5–113.0) 0.5 VT ROI4 (units) 290 (200–708) 450 (286–664) 15.0 (−21.0–77.0) 0.4 VT consolidation (units) 290 (233–760) 489 (198–783) 2.5 (−57.0–40.5) 0.9 EELI global (units) 1444 (992–3468) 2921 (1706–4850) 826.0 (399.5–2361.0) <0.0001 EELI ROI1 (units) 278 (91–634) 562 (215–1000) 161.5 (−19.5–322.5) 0.05 EELI ROI2 (units) 325 (181–531) 408 (355–1152) 187.5 (−31.5–464.0) 0.1 EELI ROI3 (units) 378 (125–446) 618 (370–1251) 220.0 (57.0–719.0) 0.01 EELI ROI4 (units) 309 (130–499) 447 (373–738) 169.5 (31.0–1104.0) 0.01 EELI consolidation (units) 283 (125–477) 486 (381–946) 138.0 (24.5–613.0) 0.01 Respiratory rate (breaths·min−1) 25 (23–28) 23 (21–26) −3 (−6–1) 0.2 SpO2/FiO2 ratio 152 (147–152) 163 (140–200) 16.0 (−6.0–48.0) 0.1 SpO2 (%) 100 (97–100) 97 (96–100) 0 (−2–1) 0.5 Heart rate (beats·min−1) 82 (72–102) 90 (78–104) 1 (−2–4) 0.4 SBP (mmHg) 118 (107–133) 125 (113–137) 6 (0–9) 0.1 MAP (mmHg) 81 (74–92) 85 (77–94) 2 (1–7) 0.01 Dyspnoea score (0–10) 0 (0–5) 5 (2–5) 0 (0–3) 0.3 Patient comfort score (0–10) 8 (4–9) 5 (4–7) −2 (−4–0) 0.1 Bold type reprensents statistical significance. IQR: interquartile range; VT: tidal volume variation; ROI: region of interest; EELI: end-expiratory lung impedance; SpO2: pulse oxygen saturation; FiO2: inspiratory oxygen fraction; SBP: systolic blood pressure; MAP: mean arterial pressure. #: Wilcoxon signed rank test.
- TABLE 4
Comparison between physiological effects of face mask (FM) and noninvasive ventilation (NIV)
FM NIV NIV–FM Median (IQR) Median (IQR) Median (95% CI) p-value# VT global (units) 2402 (1641–3050) 3161 (1884–3805) 606.0 (441.5–792.0) <0.0001 VT ROI1 (units) 593 (566–737) 887 (657–1033) 182.5 (97.0–269.0) 0.001 VT ROI2 (units) 479 (321–683) 686 (413–925) 182.5 (122.5–251.0) <0.0001 VT ROI3 (units) 649 (427–836) 743 (498–1008) 132.5 (73.5–194.5) 0.0002 VT ROI4 (units) 383 (259–772) 444 (318–861) 98.5 (17.0–178.0) 0.02 VT consolidation (units) 593 (160–819) 778 (338–1002) 151.0 (58.0–215.5) 0.009 EELI global (units) 1999 (764–2779) 4083 (2928–5134) 1810.5 (857.0–2646.0) 0.001 EELI ROI1 (units) 327 (115–618) 842 (646–1144) 518.0 (315.5–779.0) <0.0001 EELI ROI2 (units) 361 (135–880) 960 (469–1406) 457.5 (130.0–818.0) 0.009 EELI ROI3 (units) 317 (144–567) 767 (336–1124) 414.0 (76.0–678.5) 0.02 EELI ROI4 (units) 382 (115–572) 846 (488–971) 374.0 (108.0–670.5) 0.01 EELI consolidation (units) 562 (160–776) 899 (767–1144) 404.5 (59.0–718.0) 0.02 Respiratory rate (breaths·min−1) 26 (25–30) 24 (22–27) −2 (−6–2) 0.6 SpO2/FiO2 ratio 152 (145–152) 167 (143–200) 21.0 (2.5–50.0) 0.03 SpO2 (%) 100 (96–100) 100 (98–100) 0 (0–2) 0.3 Heart rate (beats·min−1) 85 (79–103) 84 (68–98) −1 (−3–5) 0.8 SBP (mmHg) 122 (109–129) 119 (108–131) −1 (−7–11) 1.0 MAP (mmHg) 84 (77–91) 80 ( 76–89) −1 (−2–4) 1.0 Dyspnoea score (0–10) 2 (0–5) 5 (0–5) 0 (−1–3) 0.5 Patient comfort score (0–10) 8 (5–10) 4 (2–5) −3 (−5− −1) 0.001 Bold type reprensents statistical significance. IQR: interquartile range; VT: tidal volume variation; ROI: region of interest; EELI: end-expiratory lung impedance; SpO2: pulse oxygen saturation; FiO2: inspiratory oxygen fraction; SBP: systolic blood pressure; MAP: mean arterial pressure. #: Wilcoxon signed rank test.
Supplementary Material
Please note: supplementary material is not edited by the Editorial Office, and is uploaded as it has been supplied by the author.
Supplementary material 00373-2021.SUPPLEMENT
FIGURE S1 Study protocol, electrode position of the electrical impedance tomography (EIT) belt and lung volume modelization. A. Progress of the experiment: after study inclusion, the first patient included received NIV in period 1 followed by HFNC in period 2. Then, the following patient received HFNC and NIV in the reverse order of the previous patient. To minimize the residual effect from period 1, patients received FM between the 2 periods. Oxygenation was delivered during at least 15 minutes. During this time, EIT measures were recorded. Electrical impedance tomography lay out: B. 16 electrodes united within the same belt were placed on the thorax of the patient facing the alveolar zone of condensation. The reference electrode R was placed on the abdomen. C. Functional EIT images in the acquisition zone defined by the belt. D. Subdivision of the acquisition area into 4 standardized quadrants or regions of interest (ROI) numbered from 1 to 4. 00373-2021.figureS1
FIGURE S2 Electrical impedance tomography recordings. EIT: electrical impedance tomography, A: respiratory rate, global and regional tidal variation (TV) in the four regions of interest (ROI) chosen. End-expiratory lung impedance (EELI) measured by EIT in global lung and in each ROI showing the evolution of EELI between B: face mask (green arrows) and NIV (pink arrows) periods; C: HFNC (red arrows) and face mask (green arrows) periods. 00373-2021.figureS2
TABLE S1 Comparison of patients' characteristics at inclusion by treatment sequence 00373-2021.tableS1
TABLE S2 Effect of first treatment on patients' characteristics just before second treatment 00373-2021.tableS2
