Table 2 Demographics and clinical characteristics of patients (N = 5163) treated by the Tochigi Helicopter Emergency Medical Services

Sex

Men

2874 (68.2)

356 (65.0)

259 (64.8)

3489 (67.6)

Age (in years; mean ± SD)

55.2 ± 24.5

57.7 ± 24.5

58.6 ± 26.1

55.7 ± 24.7

0–9

342 (8.1)

36 (6.6)

19 (4.8)

397 (7.7)

10–19

223 (5.3)

25 (4.6)

42 (10.5)

290 (5.6)

20–29

193 (4.6)

27 (4.9)

12 (3.0)

232 (4.5)

30–39

226 (5.4)

28 (5.1)

22 (5.5)

276 (5.3)

40–49

391 (9.3)

60 (10.9)

31 (7.8)

482 (9.3)

50–59

540 (12.8)

53 (9.7)

37 (9.3)

630 (12.2)

60–69

892 (21.2)

105 (19.2)

60 (15.0)

1057 (20.5)

70–79

825 (19.6)

104 (19)

87 (21.8)

1016 (19.7)

80–89

525 (12.5)

93 (17)

62 (15.5)

680 (13.2)

90–99

58 (1.4)

17 (3.1)

27 (6.8)

102 (2.0)

100 >

0 (0.0)

0 (0.0)

1 (0.3)

1 (0.0)

Year

2012

483 (11.5)

68 (12.4)

33 (8.3)

584 (11.3)

2013

491 (11.6)

69 (12.6)

20 (5.0)

580 (11.2)

2014

552 (13.1)

78 (14.2)

42 (10.5)

672 (13.0)

2015

612 (14.5)

88 (16.1)

54 (13.5)

754 (14.6)

2016

553 (13.1)

59 (10.8)

67 (16.8)

679 (13.2)

2017

501 (11.9)

62 (11.3)

42 (10.5)

605 (11.7)

2018

514 (12.2)

56 (10.2)

71 (17.8)

641 (12.4)

2019

509 (12.1)

68 (12.4)

71 (17.8)

648 (12.6)

Season

Spring (March–May)

1112 (26.4)

122 (22.3)

89 (22.3)

1323 (25.6)

Summer (June–August)

1112 (26.4)

130 (23.7)

119 (29.8)

1361 (26.4)

Autumn (September–November)

1029 (24.4)

130 (23.7)

100 (25.0)

1259 (24.4)

Winter (December-February)

962 (22.8)

166 (30.3)

92 (23.0)

1220 (23.6)

Median Distance (in km) (IQR)

27.4 (15.9–37.7)

25.4 (14.3–34.4)

29.7 (18.9–38.3)

27.4 (15.8–37.1)

Missing

110 (2.6)

16 (2.9)

26 (6.5)

152 (2.9)

Time from helicopter takeoff to flight doctor encounter, min mean ± SD

14.5 ± 12.7

15.8 ± 17.8

15.1 ± 6.6

14.7 ± 13.0

Missing

119 (2.8)

43 (7.8)

48 (12.0)

210 (4.1)

Diagnosis

Trauma

1490 (35.3)

145 (26.5)

111 (27.8)

1746 (33.8)

Neurology

395 (9.4)

70 (12.8)

47 (11.8)

512 (9.9)

Cardiovascular diseases

1385 (32.9)

167 (30.5)

74 (18.5)

1,626 (31.5)

Ischemic heart disease

379 (9.0)

40 (7.3)

6 (1.5)

425 (8.2)

Aortic disease

94 (2.2)

4 (0.7)

3 (0.8)

101 (2.0)

Stroke

772 (18.3)

103 (18.8)

54 (13.5)

929 (18.0)

Others

140 (3.3)

20 (3.6)

11 (2.8)

171 (3.3)

Cardiopulmonary arrest

99 (2.3)

34 (6.2)

10 (2.5)

143 (2.8)

Respiratory disease

70 (1.7)

7 (1.3)

12 (3.0)

89 (1.7)

Gastroenterology

113 (2.7)

11 (2.0)

17 (4.3)

141 (2.7)

Allergies

163 (3.9)

18 (3.3)

15 (3.8)

196 (3.8)

Toxicosis

58 (1.4)

16 (2.9)

3 (0.8)

77 (1.5)

Other diseases

442 (10.5)

80 (14.6)

111 (27.8)

633 (12.3)

Pre-hospital severity

Mild

494 (11.7)

83 (15.1)

147 (36.8)

724 (14.0)

Moderate

1221 (29.0)

193 (35.2)

156 (39.0)

1570 (30.4)

Severe

2485 (59.0)

265 (48.4)

86 (21.5)

2,836 (54.9)

Death

7 (0.2)

7 (1.3)

1 (0.3)

15 (0.3)

Missing

8 (0.2)

0 (0)

10 (2.5)

18 (0.3)

Pre-hospital GCS

3–8

896 (21.3)

152 (27.7)

51 (12.8)

1099 (21.3)

9–13

749 (17.8)

93 (17.0)

64 (16.0)

906 (17.5)

14–15

2535 (60.1)

297 (54.2)

271 (67.8)

3103 (60.1)

Missing

35 (0.8)

6 (1.1)

14 (3.5)

55 (1.1)

Pre-hospital interventions

Intravenous drip

3954 (93.8)

509 (92.9)

345 (86.3)

4808 (93.1)

Oxygen administration

3185 (75.6)

378 (69.0)

191 (47.8)

3754 (72.7)

Ultrasound examination

2513 (59.6)

296 (54.0)

226 (56.5)

3035 (58.8)

Endotracheal intubation

584 (13.9)

60 (10.9)

7 (1.8)

651 (12.6)

Pleural drainage

71 (1.7)

6 (1.1)

1 (0.3)

78 (1.5)

Chest compression

96 (2.3)

32 (5.8)

5 (1.3)

133 (2.6)

External defibrillation

145 (3.4)

19 (3.5)

4 (1.0)

168 (3.3)