Table 1.
Comparison between patients with and without ARDS
| Non-ARDS | ARDS | p value | |
|---|---|---|---|
| (n = 11) | (n = 21) | ||
| Clinical data | |||
| Age (year) | 62 (57–67) | 63 (50–71) | 0.889 |
| Body height (cm) | 154 (151–171) | 167 (163–170) | 0.176 |
| Body weight (kg) | 65 (57–76) | 63 (58–72) | 0.953 |
| APACHE II | 9 (6–12) | 16 (11–19) | 0.002 |
| Pre-operation | |||
| Lung cancer/Esophageal cancer | 6/5 | 9/5 | 0.697 |
| Hypertension (Yes/No) | 3/8 | 4/17 | 0.667 |
| ASA | 1 (1–2) | 2 (2–3) | 0.005 |
| VATS/open surgery | 11/0 | 12/3 | 0.667 |
| Blood transfusion (Yes/No) | 5/6 | 5/10 | 0.457 |
| Airway management | 9/2 | 10/5 | 0.540 |
| (double-lumen tube/bronchus blocker) | |||
| Anesthesia (volatile/intravenous) | 11/0 | 15/0 | 1.000 |
| Surgery time (minute) | 255 (245–450) | 250 (165–375) | 0.474 |
| Intraoperative I/O (ml) | 2000 (1500–2400) | 1300 (650–1800) | 0.015 |
| ICU stay days (day) | 4 (2–4) | 25 (13–42) | < 0.001 |
| RASS | 0 (0–0) | -1 (− 1–0) | 0.001 |
| Ventilator free hours | 0 (0–0) | 48 (24–68) | NA |
| Medications | |||
| Midazolam (Yes/No) | 4/7 | 20/1 | < 0.001 |
| Fentanyl (Yes/No) | 11/0 | 21/0 | 1.000 |
| Norepinephrine (Yes/No) | 0/11 | 8/13 | 0.021 |
| Dopamine (Yes/No) | 0/11 | 3/17 | 0.531 |
| Ventilator settings | |||
| FIO2 | 0.40 (0.40–0.40) | 0.70 (0.60–0.93) | < 0.001 |
| PEEP (cmH2O) | 5.0 (5.0–7.6) | 10.0 (9.7–12.0) | < 0.001 |
| RR (bpm) | 12 (12–13) | 17 (16–27) | < 0.001 |
| Pinsp (cmH2O) | 20 (20–20) | 20 (17–22) | 1.000 |
| Tinsp (sec) | 0.9 (0.9–1.0) | 0.9 (0.8–1.0) | 0.546 |
| VT (ml) | 490 (470–617) | 420 (380–540) | 0.004 |
| MV (l/min) | 6.0 (5.6–8.3) | 9.0 (6.6–10.6) | 0.142 |
| Cdyn (ml/cmH2O) | 25.0 (23.5–32.0) | 21.1 (18.0–26.7) | 0.010 |
| Arterial gas analysis | |||
| pH | 7.42 (7.37–7.46) | 7.44 (7.39–7.47) | 0.524 |
| PaO2 (mmHg) | 171 (133–230) | 79 (67–97) | < 0.001 |
| PaCO2 (mmHg) | 32 (27–39) | 39 (32–42) | 0.043 |
| HCO3− (mmol/l) | 20 (19–22) | 26 (21–28) | 0.017 |
| PaO2/FIO2 (mmHg) | 477 (343–559) | 106 (86–171) | < 0.001 |
| AaDO2 (mmHg) | 47 (34–104) | 368 (266–531) | < 0.001 |
| Time domain HRV measures | |||
| mRRI (ms) | 684 (589–874) | 604 (524–649) | 0.017 |
| SDRR (ms) | 32 (28–43) | 29 (25–36) | 0.132 |
| CVRR (%) | 4.7 (4.5–4.9) | 4.5 (4.5–5.0) | 0.284 |
| RMSSD (ms) | 31 (28–41) | 29 (25–37) | 0.204 |
| Frequency domain HRV measures | |||
| TP (ms2) | 267 (206–614) | 212 (134–316) | 0.068 |
| VLFP (ms2) | 29 (22–92) | 21 (11–47) | 0.068 |
| LFP (ms2) | 73 (48–168) | 54 (39–78) | 0.052 |
| HFP (ms2) | 171 (131–387) | 122 (83–176) | 0.043 |
| HFP/VT (ms2/ml) | 0.35 (0.22–0.81) | 0.31 (0.21–0.44) | 0.383 |
| nVLFP (nu) | 11.0 (8.6–14.2) | 9.3 (7.9–14.1) | 0.341 |
| nLFP (nu) | 27.4 (24.5–27.8) | 27.9 (26.9–28.5) | 0.361 |
| nHFP (nu) | 62.0 (60.0–64.0) | 62.9 (59.4–63.6) | 0.890 |
| nHFP/VT (nu/ml) | 0.11 (0.10–0.13) | 0.15 (0.12–0.18) | 0.011 |
| LHR | 0.45 (0.43–0.47) | 0.45 (0.44–0.48) | 0.937 |
| LHR*VT (1/ml) | 228 (209–282) | 186 (149–238) | 0.010 |
Data are presented as medians (25% - 75% interquartile range). APACHE II: Acute Physiology and Chronic Health Evaluation II; ASA: American Society of Anesthesiologists; VATS: Video-Assisted Thoracic Surgery; I/O: intake/output; RASS: Richmond Agitation-Sedation Scale; FIO2: fraction of inspired oxygen; PEEP: positive end-expiratory pressure; RR: respiratory rate; Pinsp: inspiratory pressure; Tinsp: inspiration time; VT: tidal volume; MV: minute ventilation; Cdyn: dynamic compliance; PaO2: partial pressure of arterial oxygen; PaCO2: partial pressure of arterial carbon dioxide; HCO3: bicarbonate; AaDO2: alveolo-arterial oxygen difference; ALI score: acute lung injury score; RASS: Richmond Agitation-Sedation Scale; mRRI: mean RR interval; SDRR: standard deviation of RR intervals; CVRR: coefficient of variation of RR intervals; RMSSD: root mean squared successive difference; TP: total power; VLFP: very low-frequency power; LFP: low-frequency power; HFP: high-frequency power; nVLFP: normalized VLFP; nLFP: normalized LFP; nHFP: normalized HFP; body weight; LHR: 4 low-/high- frequency power ratio; ml: milliliter; bpm: beats per minute; ms: milliseconds; nu: normalized unit; NA: not assessed. The "*" in "LHR*VT" denotes multiplication