Table 1 Baseline characteristics of patients with critical MIS-C, according to in-hospital mortality.

Epidemiological and demographics

 Age in months median (IQR)

28 (5–119)

17 (5–33)

23 (5–112)

0.126

 Children under 2 years old n (%)

29 (46.8)

11 (64.7)

40 (50.6)

0.274

 Sex: male n (%)

41 (66.1)

15 (88.2)

56 (70.9)

0.129

 Ethnicity: Brazilian pardo n (%)

30 (48.4)

10 (58.8)

40 (50.6)

0.585

 Pediatric complex chronic conditions n (%)

48 (77.4)

16 (94.1)

64 (81.0)

0.785

 Comorbidities

  Neurologic and neuromuscular diseases

13 (27.1)

6(37.5)

19 (29.7)

0.756

  Gastrointestinal diseases

9 (18.8)

4 (25)

13 (20.3)

1.000

  Respiratory diseases

8 (16.7)

3 (18.8)

11 (17.2)

1.000

  Time from exposure to symptom onset in days, median (IQR)

14 (11–21)

14 (9–25)

14 (11–23)

0.905

  Duration of fever in days, median (IQR)

11 (7–13)

8 (5–12)

10 (6–12)

0.174

 SARS-CoV-2 infection confirmed tests n (%)

  IgG

20/124 (16.1)**

3/34 (8.8)**

23/158 (14.6)**

0.412

  Antigen test

42/124 (33.9)

14/34 (41.2)

56/158 (35.4)

0.431

  RT-PCR test

12/124 (9.7)

4/34 (11.8)

16/158 (10.1)

0.75

  BMI-for-age Z-scores > 5 years old: moderately underweight n (%)

11 (17.7)

4 (23.5)

15 (19.0)

1.000

  BMI-for-age Z-scores < 5 years old: Normal weight n (%)

4 (6.5)

2 (11.8)

6 (7.6)

0.144

Clinical

 MIS-C clinical form: Shock syndrome Kawasaki disease n (%)

23 (37.1)

7 (41.2)

30 (38.0)

0.783

 Lymphadenopathy n (%)

37 (59.7)

10 (58.8)

47 (59.5)

1.000

 Severe dyspnea n (%)

17 (34.7)

12 (75)

29 (44.6)

0.008

 Gastrointestinal symptoms n (%)

40 (64.5)

14 (82.4)

54 (68.4)

0.240

 Pneumonia n (%)

35 (56.5)

13 (76.5)

48 (60.8)

0.168

 Exanthema n (%)

40 (64.5)

15 (88.2)

55 (69.6)

0.078

 Cardiogenic Shock n (%)

20 (42.6)

13 (76.5)

33 (51.6)

0.023

 VIS median (IQR)

12 (0–71)

163 (121–176)

39 (0–91)

 < 0.001

 Oxygen therapy modalities n (%)

  Oxygen low interfaces

11 (17.7)

0 (0)

11 (13.9)

0.108

  Invasive mechanical ventilation

38 (61.3)

17 (100)

55 (69.6)

 < 0.001

  Non-invasive mechanical ventilation

13 (21.0)

0 (0)

13 (16.5)

0.059

Ventilator weaning success at first attempt n (%)

36 (94.7)

5 (5.9)

41 (74.5)

 < 0.001

Tracheostomy tube use n (%)

2 (5.3)

1 (5.9)

3 (5.5)

1.000

ADRS n (%)

23 (37.1)

17 (100)

40 (50.6)

 < 0.001

Severe ARDS n (%)

5 (8.1)

10 (58.8)

15 (19)

0.004

MOD > 2 organ involvement n (%)

41 (66.1)

17 (100)

58 (73.4)

0.004

Renal replacement therapy n (%)

8 (12.9)

1 (5.9)

9 (11.4)

0.675

KDIGO stage 1, n (%)

20 (32.3)

16 (94.1)

36 (45.6)

 < 0.001

Treatment n (%)

 Low molecular weight heparin therapy

33 (53.2)

16 (94.1)

49 (62.0)

0.003

 Methylprednisolone pulse therapy

6 (9.7)

13 (76.5)

19 924.1)

0.002

 Intravenous immunoglobulin therapy

37 (59.7)

17 (100)

54 (68.4)

0.002

Outcomes median (IQR)

 Length of stay at hospital, in days

15 (10–18)

11 (6–14)

14 (9–18)

0.105

 Length of stay at PICU, in days

6 (4–8)

11 (6–14)

6 (4–9)

0.01

 Mechanical ventilation time, in days

4 (3–6)

11 (6–14)

4 (3–9)

 < 0.001

 Ventilator free days at 28^th

24 (22–25)

0 (0–1)

22 (1–25)

 < 0.001

 PRISMIV%

1.5 (1.2–2.8)

5.9 (1.9–32)

2.8 (1.5–26.4)

0.009

 PELOD-2

9.5 (5–20)

15 (3–21)

11 (4–20)

0.9

Ventilatory settings and Respiratory mechanics median (IQR) Day 1

 Tidal volume in ml/kg

6.3 (5.4–7.3)

9.9 (9.3–10.6)

6.9 (5.6–9.5)

 < 0.001

 Respiratory rate breaths/min

24 (23–29)

25 (22–30)

26 (23–30)

0.813

 Peep-peak paw in cmH₂O

9 (7–10)

22 (18–24)

17 (10–23)

0.001

 Driving pressure in cmH₂O

9 (8–11)

17 (16–18)

11 (9–16)

 < 0.001

 Compliance respiratory system in mL/cmH₂O/kg

0.6 (0.59–0.89)

0.67 (0.42–0.99)

0.64 (0.56–0.97)

0.91

 Ventilatory ratio^a

0.68 (0.48–1.61)

0.76 (0.62–1.13)

0.74 (0.53–1.3)

0.698

Laboratorial features median (IQR) Day 1

 Oxygenation index

5.3 (2.5–10)

10.6 (8.9–15.6)

8.4 (3.5–12.3)

 < 0.001

 PaO₂/FiO₂ ratio

238 (160–367)

159 (111–181)

204 (141–358)

 < 0.001

 pO₂ (mmHg)

125.5 (72.4–180)

128 (73–151)

128 (72.4–179)

0.456

 pCO₂ (mmHg)

37.6 (28.6–55.9)

37 (29.4–50.6)

37.1 (28.8–55.9)

0.952

 Sodium bicarbonate (mmol/L)

20.9 (18.2–23.7)

15.7 (13.8–22.9)

20.7 (16.3–23.7)

0.043

 Anion gap (mmol/L)

7.7 (12.2–16.9)

18.2 (10.4–24.9)

16.9 (9.5–21.4)

0.016

 Lactate (mmol/L)

2.3 (1.7–2.9)

2.7 (2–2.9)

2.3 (1.7–2.9)

0.962

 Platelets count/mm³

194,000 (120,000–352,000)

28,000 (19,700–31,300)

152,000 (45,300–308,000)

 < 0.001

 Lymphocytes count/mm³

1,352 (1,038–1,998)

1,033 (774–1,428)

1,270 (978–1,870)

0.023

 INR

1.2 (1.0–1.5)

1.2 (1.0–1.7)

1.2 (1–1.5)

0.440

 d-Dimer (ng/dL)

1,917 (959–5,009)

1,606 (1,209–2,938)

1,789 (959–4,254)

0.872

 Fibrinogen (mg/dL)

288 (145–453)

226 (160–254)

269 (145–385)

0.113

 C-reactive protein(mg/dL)

34 (14,6–80,8)

77.6(34.5–88.7)

40.7 (16.2–85)

0,09

 Erythrocyte sedimentation rate (mm/h)

12 (8–16)

45 (35–54)

14 (9–22)

 < 0.001

 Ferritin (ng/mL)

548 (291–597)

582 (482–1,112)

550 (298–616)

0.018

 Urea (mg/dL)

26 (17–46)

22 (19–38)

25 (17–46)

0.441

 Creatinine (mg/dL)

0.4 (0.3–0.9)

0.4 (0.3–0.4)

0.4 (0.3–0.8)

0.480

 AST (IU/L)

45 (35–75)

50 (38–64)

46 (35–75)

0.527

 ALT (IU/L)

35 (17–52)

38 (17–60)

35 (17–52)

0.716

 Albumin (g/dL)

2.7 (2.3–3.8)

2.9 (2.5–3.5)

2.7 (2.3–3.8)

0.810

 Troponin I (ng/L)

0.124 (0.01–1.35)

4.57 (2.1–11.31)

0.27 (0.03–2.8)

 < 0.001

Ventilatory settings and Respiratory mechanics median (IQR) Day 2

 Tidal volume in ml/kg

5.8 (5.2–7.4)

9.7 (9–10)

7.2 (5.5–9.6)

 < 0.001

 Respiratory rate breaths/min

27 (23–29)

28 (22–30)

28 (23–30)

0.813

 Peep- Peak Paw in cmH₂O

10 (7–11)

19 (17–23)

17(10–22)

0.001

 Driving pressure in cmH₂O

10 (9–12)

16 (15–17)

12 (9–16)

 < 0.001

 Compliance respiratory system in mL/cmH₂O/kg

0.89 (0.6–1.13)

0.84 (0.51–1.12)

0.87 (0.57–1.12)

0.68

 Ventilatory ratio^a

0.86 (0.6–1.08)

1.06 (0.88–2.2)

1.0 (0.69–1.86)

0.126

Laboratorial features median (IQR) Day 2

 Oxygenation index

4.1 (2.3–8.1)

10.9 (4.9–13.9)

6.5 (3.3–10.9)

0.006

 PaO₂/FiO₂ ratio

348 (183–450)

151 (102–242)

257 (150–425)

0.001

 pO₂ (mmHg)

124 (58–157)

106 (59–131)

111 (55–147.5)

0.116

 pCO₂ (mmHg)

42 (34–65)

46 (42–49)

45 (34–63)

0.479

 Sodium bicarbonate (mmol/L)

23 (19.4–27)

18.1 (15.8–20.3)

21 (17.7–25.6)

0,002

 Anion gap (mmol/L)

11.7 (5.2–20.7)

15.3 (10.4–23.8)

13.3 (6.7–21.5)

0.07

 Lactate (mmol/L)

1.4 (1–2.8)

3.5 (2.1–7.9)

1.9 (1.2–4)

0.059

 Platelets count/mm³

265,800 (135,000–376,700)

301,000 (172,000–450,000)

279,000 (138,600–448,000)

0.761

 Lymphocytes count/mm³

2,266 (1,346–5,000)

1,807 (1,102–2,934)

2,246 (1,248–4,525)

0.095

 INR

1.1 (1–1.4)

1.11 (1.02–1.3)

1.1 (1.01–1.38)

0.2

 d-Dimer (ng/dL)

1,002 (602 -1,795)

1,291 (690–3,861)

1,264 (609–3,861)

0.161

 Fibrinogen (mg/dL)

203 (101–380)

170 (64–381)

203 (78–380)

0.605

 C-reactive protein(mg/dL)

21 (7.8–41)

23 (7.5–67)

20 (7.3–60)

0.938

 Erythrocyte sedimentation rate (mm/h)

20 (10–20)

56 (51–60)

20 (12–30)

 < 0.001

 Ferritin (ng/mL)

149 (94–851)

329 (169–580)

329 (132–580)

0,06

 Urea (mg/dL)

15 (7–49)

34 (19–56)

31 (14–52)

0.037

 Creatinine (mg/dL)

0.3 (0.25–0.5)

0.45 (0.25–0.6)

0.4 (0.25–0.6)

0.417

 AST (IU/L)

41 (33–80)

53 (33–62)

49 (33–70)

0.605

 ALT (IU/L)

31 (16–55)

32 (17–60)

31 (16–56)

0.543

 Albumin (g/dL)

2.7 (2.4–3.2)

2.8 (2.3–3.1)

2.8 (2.5–3.2)

0.272

 Troponin I (ng/L)

0.1 (0.01–7.8)

0.2 (0,02–19.5)

0.2 (0.012–13.4)

0.889