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Table 2 Clinical variables, gas exchange, cardiac function and lung aeration before and at the end of the spontaneous breathing trial

From: Diaphragm dysfunction, lung aeration loss and weaning-induced pulmonary oedema in difficult-to-wean patients

  Before the SBT End of the SBT
SBT success SBT failure p SBT success SBT failure p
n 22 31   22 31  
Clinical variables
 Systolic ABP, mmHg 121 (110–139) 140 (118–151) 0.041 130 (109–154) 149 (128–170) 0.007
 Heat rate, min−1 94 (77–101) 93 (84–104) 0.840 97 (86–105) 105 (96–121) 0.036
 Respiratory rate, min−1 19 (15–23) 21 (18–26) 0.101 21 (19–31) 28 (21–35) 0.030
Laboratory variables
 pH 7.42 (7.38–7.48) 7.43 (7.38–7.45) 0.732 7.43 (7.40–7.47) 7.38 (7.34–7.43) 0.027
 PaO2/FiO2 ratio 327 (237–381) 227 (168–280) 0.004 253 (197–298) 160 (107–205)  < 0.001
 PaCO2, mmHg 36 (30–43) 42 (36–49) 0.009 39 (33–43) 50 (38–57) 0.002
 Lactate, mmol.L−1 1.2 (0.8–1.6) 1.3 (1.0–1.8) 0.254 0.9 (0.7–1.2) 1.1 (1.0–1.5) 0.015
 Haemoglobin, g.dL−1 8.3 (7.8–10.4) 9.4 (8.4–10.7) 0.227 8.6 (7.9–10.7) 9.8 (8.8–11.5) 0.073
 Delta haemoglobin, %   0 (-5–5) 5 (1–9) 0.013
 Protein, g.L−1 55 (48–59) 60 (54–65) 0.021 53 (49–59) 64 (58–69) 0.001
 Delta protein, %   4 (0–5) 7 (2–9) 0.014
Cardiac function
 LEVF, % 60 (50–60) 60 (50–60) 0.319 60 (50–60) 60 (50–60) 0.321
 CI, L.min−1.m−2 3.1 (2.6–3.9) 3.6 (2.9–4.2) 0.264 3.6 (2.8–4.1) 4.3 (3.6–4.9) 0.167
 e’ wave, cm.s−1 11 (9–12) 10 (9–12) 0.904 10 (9–13) 11 (9–13) 0.939
 E/A ratio 0.8 (0.7–1.1) 1.0 (0.8–1.4) 0.177 0.9 (0.7–0.9) 1.1 (0.9–1.3) 0.001
  E/e’ ratio 7.1 (5.3–8.6) 8.1 (6.6–10.5) 0.092 7.4 (5.3–9.2) 9.3 (7.2–1.28) 0.022
 E/e’ > 14, n (%) 2 (10) 1 (3)   1 (10) 5 (19)  
 DTE, ms 175 (142–210) 172 (137–201) 0.967 169 (142–228) 157 (140–200) 0.329
 Systolic PAP, mmHg 23 (20–28) 27 (20–35) 0.255 24 (21–36) 30 (21–53) 0.165
 TAPSE, cm 2.3 (1.9–2.6) 2.1 (1.9–2.7) 0.988 2.3 (2.1–2.7) 2.3 (1.9–2.9) 0.839
 S wave, cm s−1 15.8 (13.7–18.7) 16 (14.0–21.1) 0.621 17.4 (14.1–20.1) 17.0 (15.6–20.5) 0.829
Diaphragm function
 Ptr,stim, cmH2O 6.8 (3.4–8.8) 4.1 (2.7–7.9) 0.098 6.0 (3.8–8.3) 4.3 (2.2–6.9) 0.192
Lung aeration
 Lung consolidation, n 2 (1–4) 4 (0–10) 0.026 2 (0–1) 6 (0–10) 0.025
 LUS 10 (3–19) 17 (4–33) 0.123 9 (3–20) 20 (5–33) 0.060
 Posterior LUS 7 (2–12) 10 (1–17) 0.377 6 (2–14) 11 (4–17) 0.112
  1. SBT, spontaneous breathing trial; ABP, arterial blood pressure; LEVF, left ventricular ejection fraction; CI, cardiac index; E/A, early (E) over late (A) diastolic wave velocity ratio; E/e’, E wave over tissue Doppler early (e’) wave velocities at the lateral mitral valve annulus; DTE, deceleration time of the E wave; TAPSE, tricuspid annular plane systolic excursion (TAPSE); PAP, pulmonary artery pressure; LUS, lung ultrasound score