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. 2020 Dec 26;126(3):e130–e132. doi: 10.1016/j.bja.2020.12.023

Table 1.

Characteristics and outcomes with comparisons between phenotypes

All patients (n=56) Phenotype 1 (n=24) Phenotype 2 (n=20) Phenotype 3 (n=12) P-value
Patient characteristics
Age, yr∗ 46.0 [37.5–52.2] 41 [34.8–48.0] 51 [45.2–53.0] 49 [44.8–54.2] 0.012
Body masss index (BMI)∗ 29.5 [27.0–34.0] 29.0 [26.8–34.2] 29.5 [27.0–33.5] 32.0 [29.0–34.0] 0.621
Female 15 (26.8) 10 (41.7) 3 (15) 2 (16.7) 0.093
Ethnicity
  • -

    White

  • -

    Black

  • -

    South/East Asian

 23 (41.1)
11 (19.6)
22 (39.3)		 10 (41.7)
1 (4.2)
13 (54.2)		 6 (30)
8 (40)
6 (30)		 7 (58.3)
2 (16.7)
3 (25)		 0.287
0.011
0.137
Comorbidity
  • -

    Diabetes mellitus

  • -

    Asthma

  • -

    Hypertension

 8 (14.3)
6 (10.7)
11 (19.6)		 1 (4.2)
3 (12.5)
3 (12.5)		 4 (20)
1 (5)
7 (35)		 3 (25)
2 (16.7)
1 (8.3)		 0.160
0.546
0.094
Clinical characteristics
Days from ED to IMV∗ 2 [0.8–4.0] 1.0 [0.0–4.0] 1.0 [0.0–3.0] 6.0 [3.0–8.2] <0.001
Days from IMV to ECMO∗ 4 [1.8–6.0] 3.5 [2.0–5.2] 6.0 [5.0–6.0] 1.0 [1.0–1.0] <0.001
RESP score† 4 [3.0–5.0] 4.0 [4.0–5.0] 3.0 [2.8–4.2] 5.5 [4.0–6.2] 0.001
SOFA score∗ 6 [4.0–9.0] 4.5 [4.0–6.0] 8.0 [5.8–11.2] 6.5 [4.0–9.0] 0.006
PF ratio (kPa)∗ 9.19 [7.97–10.51] 9.85 [9.00–11.81] 8.74 [7.80–9.76] 7.99 [6.80–9.31] 0.004
Pco2 (kPa)∗ 9.00 [7.20–9.89] 8.91 [7.11–9.40] 9.60 [7.80–11.60] 8.80 [7.51–9.91] 0.310
Plateau pressure (cm H2O)∗ 30.0 [27.8–31.2] 30.0 [25.8–31.0] 31.0 [30.0–32.2] 29.2 [27.8–29.4] 0.020
Corticosteroids given pre-ECMO 10 (17.9) 7 (29.2) 1 (5.0) 2 (16.7) 0.113
Antimicrobials given pre-ECMO 56 (100) 24 (100) 20 (100) 12 (100) 1
ECMO Day 0 laboratory values
Lymphocytes (10ˆ9 L−1)∗ 0.6 [0.5–1.0] 0.6 [0.5–1.1] 0.8 [0.6–1.2] 0.4 [0.4–0.6] 0.013
N:L ratio∗ 13.9 [9.3–22.0] 11.8 [9.5–16.9] 10.6 [7.6–16.3] 23.2 [19.3–34.1] <0.001
Procalcitonin (ng ml−1)∗ 3.6 [1.1–9.4] 1.2 [0.8–3.7] 8.1 [3.1–32.5] 5.3 [1.8–8.6] 0.005
Ferritin (μg L−1)∗ 1783.0 [997.5–3851.8] 1613 [846–2841] 1710 [1052–4328] 1932 [1619–4389] 0.340
CRP (mg L−1)∗ 310.5 [207.8–356.8] 194 [105–277] 355 [326–469] 333 [235–380] <0.001
Fibrinogen (g L−1)∗ 6.8 [5.3–8.6] 5.4 [4.5–8.2] 8.2 [7.2–9.8] 6.3 [4.9–7.1] 0.001
D-dimer (mg L−1 FEU)∗ 9.2 [5.3–33.6] 5.2 [3.2–7.1] 30.1 [19.5–47.9] 31.6 [8.6–64.3] <0.001
Outcome features
Survival to 60 days 40 (71.4) 23 (95.8) 11 (55) 6 (50) 0.002
Peak norepinephrine requirement (μg kg−1 min−1) 0.1 [0.0–0.2] 0.07 [ 0–0.18] 0.19 [0.09–0.30] 0.14 [0.06–0.23] 0.098
Renal replacement therapy 22 (39.3) 4 (16.7) 13 (65) 5 (41.7) 0.005
Significant positive microbiology on admission BAL 10 (17.9) 4 (16.7) 6 (30.0) 0 (0.0) 0.098
Pulmonary embolism 15 (26.8) 7 (29) 4 (20) 4 (33) 0.670
Pneumothorax 15 (26.8) 6 (25.0) 6 (30.0) 3 (25.0) 0.921
Duration of ECMO (days) 13 [8.0–21.0] 16 [9–21] 13 [7–16] 12 [8–31] 0.330
Survivors only 13.5 [8.8–21.0] 16 [ 9–21.5] 13 [6–14.5] 12 [10–19]
Causes of death
Multi-organ failure 7 (12.5) 0 (0) 6 (30) 1 (8.3) 0.010
Intracranial bleed 2 (3.6) 0 (0) 1 (5) 1 (8.3) 0.407
Ischaemic stroke 2 (3.6) 1 (4.2) 0 (0) 1 (8.3) 0.459
Irreversible pulmonary fibrosis 2 (3.6) 0 (0) 0 (0) 2 (16.7) 0.022
Cardiac tamponade 2 (3.6) 0 (0) 1 (5) 1 (8.3) 0.407
Major haemorrhage 1 (1.8) 0 (0) 1 (5) 0 (0) 0.400

Values represented as median [inter-quartile range] or n (%). P-values represent significant difference across clusters 1, 2, and 3 when using the Kruskal-Wallis test (or Pearson's χ2 test for categorical variables).

BAL, bronchoalveolar lavage; CRP, C-reactive protein; ECMO, extracorporeal membrane oxygenation; ED, emergency department; IMV, invasive mechanical ventilation; L, lymphocyte; N, neutrophil; PF, partial pressure of arterial oxygen to fractional inspired oxygen; SOFA, sequential organ failure assessment.

∗

Input variables used in cluster analysis.

†

Respiratory ECMO survival prediction (RESP) score was not included in cluster analysis and is shown for added informational value.