Table 1.
Demographic, Clinical, and Mechanical Ventilation Characteristics before Extracorporeal Membrane Oxygenation Cannulation, for the Overall Cohort and Stratified by Obesity
| BMI (kg/cm2) |
|||||
|---|---|---|---|---|---|
| All Patients (n = 790) | Patients without Obesity (n = 470) | Patients with Obesity (n = 320) | P Value | SMD | |
| Age, yr | 44.2 ± 15.5 | 44.1 ± 16.8 | 44.4 ± 13.4 | 0.753 | 0.022 |
| Sex | 0.018 | 0.176 | |||
| Female | 286 (36.2) | 154 (32.8) | 132 (41.2) | — | — |
| Male | 504 (63.8) | 316 (67.2) | 188 (58.8) | — | — |
| BMI, kg/cm2 | 30.3 ± 9.2 | 24.6 ± 3.3 | 38.8 ± 8.3 | <0.001 | 2.255 |
| BMI ⩾ 30 kg/cm2 | 320 (40.5) | 0 (0.00) | 320 (100) | <0.001 | — |
| BMI ⩾ 35 kg/cm2 | 193 (24.4) | 0 (0.00) | 193 (60.3) | <0.001 | — |
| BMI ⩾ 40 kg/cm2 | 110 (13.9) | 0 (0.00) | 110 (34.4) | <0.001 | — |
| APACHE II score | 23.3 ± 9.7 (n = 660) | 23.9 ± 10.1 (n = 425) | 22.2 ± 8.9 (n = 235) | 0.028 | 0.175 |
| SOFA score | 10.0 ± 4.1 (n = 772) | 10.0 ± 4.4 (n = 461) | 9.9 ± 3.7 (n = 311) | 0.795 | 0.019 |
| Duration of IMV before ECMO, d | 2.00 (1.00–6.00) | 2.00 (1.00–6.00) | 3.00 (1.00–6.00) | 0.165 | 0.020 |
| Ventilation parameters | |||||
| FiO2, mm Hg | 100 (100–100) (n = 762) | 100 (100–100) (n = 447) | 100 (100–100) (n = 315) | 0.054 | 0.155 |
| PEEP, cm H2O | 14 (10–16) (n = 717) | 12 (10–15) (n = 423) | 15 (12–18) (n = 294) | <0.001 | 0.466 |
| Vt, ml/kg PBW | 6.33 ± 1.88 (n = 419) | 6.13 ± 1.63 (n = 287) | 6.79 ± 2.26 (n = 132) | 0.003 | 0.335 |
| Plateau pressure, cm H2O | 32 [29–35] (n = 529) | 31 [28–35] (n = 331) | 32 [30–36] (n = 198) | 0.001 | 0.328 |
| Driving pressure, cm H2O* | 18 [14–22] (n = 274) | 18 [14–23] (n = 148) | 18 [14–22] (n = 126) | 0.951 | 0.006 |
| Respiratory rate, breaths/min | 25.0 ± 7.6 (n = 686) | 24.5 ± 7.7 (n = 402) | 25.8 ± 7.3 (n = 284) | 0.023 | 0.176 |
| Precannulation arterial blood gas values | |||||
| pH | 7.24 ± 0.14 (n = 735) | 7.24 ± 0.14 (n = 433) | 7.24 ± 0.14 (n = 302) | 0.774 | 0.021 |
| PaCO2, mm Hg | 62.7 ± 26.7 (n = 628) | 61.0 ± 23.6 (n = 402) | 65.6 ± 31.2 (n = 226) | 0.055 | 0.166 |
| Worst PaO2:FiO2 ratio | 68.4 ± 30.3 (n = 755) | 71.5 ± 31.1 (n = 447) | 63.9 ± 28.6 (n = 308) | 0.001 | 0.257 |
| Rescue therapy before ECMO | |||||
| Neuromuscular blockade | 499 (63.2) | 280 (59.6) | 219 (68.4) | 0.014 | 0.185 |
| Inhaled nitric oxide | 234 (29.6) | 141 (30.0) | 93 (29.1) | 0.838 | 0.021 |
| Prone positioning | 152 (19.2) | 94 (20.0) | 58 (18.1) | 0.572 | 0.048 |
| HFOV | 36 (4.6) | 21 (4.5) | 15 (4.7) | 1.000 | 0.010 |
| RRT before ECMO | 226 (28.6) | 131 (27.9) | 95 (29.7) | 0.635 | 0.040 |
Definition of abbreviations: APACHE = Acute Physiology and Chronic Health Evaluation; BMI = body mass index; ECMO = extracorporeal membrane oxygenation; HFOV = high-frequency oscillatory ventilation; IMV = invasive mechanical ventilation; PBW = predicted body weight; PEEP = positive end-expiratory pressure; RRT = renal replacement therapy; SMD = standardized mean difference; SOFA = sequential organ failure assessment.
Data are expressed as mean ± SD, n (%), or median (interquartile range).
*
Plateau pressure minus PEEP.