Background
Methods
Patients
Measurement set-up
Protocol
Data analysis
Statistical analysis
Results
Patients sample description
Patient | Age (years) | Gender | BMI (kg/m2) | SAPSII | SOFA | ETT ID (mm) | PS (cmH2O) | VT (ml/kg PBW) | PEEP (cmH2O) | Status at ICU discharge |
---|---|---|---|---|---|---|---|---|---|---|
1 | 64 | F | 20 | 67 | 2 | 7.0 | 3 | 10 | 4 | D |
2 | 60 | F | 30 | 31 | 3 | 7.0 | 10 | 9 | 5 | A |
3 | 64 | M | 30 | 35 | 5 | 7.5 | 7 | 10 | 4 | A |
4 | 55 | F | 13 | 34 | 4 | 7.0 | 7 | 6 | 5 | A |
5 | 59 | M | 23 | 31 | 13 | 8.0 | 10 | 7 | 4 | A |
6 | 70 | M | 29 | 63 | 9 | 8.0 | 7 | 7 | 5 | A |
7 | 62 | M | 36 | 43 | 4 | 8.0 | 12 | 4 | 5 | A |
8 | 62 | F | 23 | 52 | 13 | 7.5 | 10 | 0 | 5 | A |
9 | 78 | M | 30 | 67 | 8 | 7.5 | 10 | 6 | 4 | A |
10 | 71 | M | 25 | 53 | 7 | 8.0 | 12 | 12 | 5 | A |
11 | 79 | M | 28 | 50 | 7 | 8.0 | 7 | 6 | 5 | A |
12 | 64 | M | 31 | 84 | 8 | 7.5 | 7 | 8 | 4 | A |
13 | 47 | M | 23 | 46 | 4 | 7.5 | 7 | 8 | 5 | A |
14 | 68 | M | 28 | 66 | 7.5 | 8 | 6 | 5 | A | |
15 | 40 | F | 29 | 40 | 3 | 7.5 | 7 | 7 | 4 | A |
16 | 59 | M | 25 | 59 | 3 | 7.5 | 10 | 5 | 5 | A |
17 | 60 | M | 42 | 35 | 12 | 8.5 | 10 | 6 | 5 | A |
18 | 66 | M | 24 | 57 | 9 | 8.5 | 10 | 8 | 5 | A |
19 | 19 | M | 33 | 37 | 2 | 8.0 | 10 | 4 | 5 | A |
20 | 63 | M | 22 | 67 | 10 | 8.5 | 10 | 5 | 5 | D |
Median (1st–3rd quartiles) | 63 (59–67) | 15 M 5 F | 28 (23–30) | 51 (37–64) | 7 (4–9) | 10 (7–10) | 7 (6–8) | 5 (4–5) |
Effects of SBT mode on breathing pattern and inspiratory effort
ATC | Low PS | P value | |
---|---|---|---|
Tidal volume (l) | 0.35 (0.30; 0.45) | 0.35 (0.32; 0.50) | 0.22 |
Tidal volume (ml/kg predicted body weight) | 5.3 (4.5; 6.3) | 5.6 (4.7; 7.7) | 0.21 |
Respiratory rate (breaths/min) | 27 (21; 33) | 25 (21; 28) | 0.007 |
Minute ventilation (l/min) | 9.5 (7.4; 11.7) | 9.4 (8.3; 10.4) | 0.22 |
Respiratory rate/tidal volume ratio (breaths/min/l) | 77 (52; 105) | 70 (43; 88) | 0.048 |
Inspiratory time (s) | 0.95 (0.78; 1.11) | 0.88 (0.80; 1.05) | 0.79 |
Expiratory time (s) | 1.44 (1.10; 1.78) | 1.72 (1.36; 1.96) | 0.05 |
Inspiratory/expiratory time ratio (%) | 0.67 (0.54; 0.81) | 0.55 (0.49; 0.71) | 0.04 |
PEEP (cmH2O) | 5 (4; 5) | 5 (4–5) | 0.60 |
DPtrig (cmH2O) | − 2 (− 3; − 1) | − 2 (− 3; − 2) | 0.60 |
DTtrig (s) | 0.19 (0.12; 0.22) | 0.15 (0.13; 0.19) | 0.007 |
Maximal inspiratory pressure (cmH2O) | 8 (7; 8) | 12 (12–12) | 0.00006 |
Maximal inspiratory flow (l/s) | 1 (1; 1) | 1 (1; 1) | 0.18 |
ATC | Low PS | Treatment effect | Period effect | Treatment × period interaction (carry over effect) | |
---|---|---|---|---|---|
Total breathing power (J/min) | 9.7 (5.7–21.9) | 7.2 (4.4–9.6) | 0.011 | 0.060 | 0.175 |
Resistive breathing power (J/min) | 4.8 (1.6–9.9) | 3.1 (1.9–4.6) | 0.035 | 0.086 | 0.116 |
Elastic breathing power (J/min) | 5.0 (3.6–7.7) | 3.5 (2.4–5.2) | 0.0096 | 0.081 | 0.238 |
Ventilator support functioning in SBT
Electrical impedance tomography
ATC | Low PS | P value | |
---|---|---|---|
Anterior-to-posterior impedance ratio | 0.69 (0.58–1.59) | 0.86 (0.49–1.61) | 0.55 |
Center of ventilation | 54.8 (46.3–58.1) | 53.7 (46.0–60.2) | 0.82 |
Global inhomogeneity index | 0.62 (0.47–0.80) | 0.65 (0.50–0.75) | 0.35 |
Coefficient of variation | 0.95 (0.81–1.82) | 0.96 (0.77–1.39) | 0.68 |
Breathing power | Electrical impedance tomography indexes | |||
---|---|---|---|---|
Anterior-to-posterior ratio | Center of ventilation | Coefficient of variation | Global inhomogeneity index | |
Elastic | − 0.38* | 0.39* | − 0.18 | 0.34* |
Resistive | − 0.39* | 0.41* | − 0.18 | 0.43* |
Total | − 0.36* | 0.37* | − 0.16 | 0.41* |