Introduction
Methods
Ethics statement
Study design and data collection
Selection of participants
Statistical analysis
Data included in the analysis
Propensity score
Patients by transportation method, n(%) | |||
---|---|---|---|
All patients | Helicopter | Ground | |
Characteristics | (N = 24,293) | (N = 2,090) | (N = 22,203) |
n (%) | |||
Sex | |||
Men | 17,265 (71.1) | 1,571 (75.2) | 15,694 (70.7) |
Women | 7,023 (28.9) | 519 (24.8) | 6,504 (29.3) |
Age, yr | |||
15 to 55 | 11,749 (48.4) | 884 (42.3) | 10,865 (48.9) |
56 to 65 | 4,279 (17.6) | 419 (20.0) | 3,860 917.4) |
>65 | 8,265 (34.0) | 787 (37.7) | 7,478 (33.7) |
Injury type | |||
Blunt | 23,680 (97.5) | 2,062 (98.7) | 21,618 (97.4) |
Penetrating | 613 (2.5) | 585 (2.6) | 28 (1.3) |
Cause of injury | |||
Motor vehicle crash | 12,638 (53.9) | 1,087 (53.2) | 11,551 (54.0) |
Falls | 8,749 (37.3) | 675 (33.0) | 8,074 (37.7) |
Other reason | 2,059 (8.8) | 283 (13.8) | 1,776 (8.3) |
Injury severity score | |||
15 to 24 | 11,747 (52.9) | 892 (47.3) | 10,855 (53.4) |
25 to 34 | 8,184 (36.8) | 738 (39.1) | 7,446 (36.6) |
35-44 | 2,279 910.3) | 256 (13.6) | 2,023 (10.0) |
TRISS (P > 0.5) | 16,578 (77.7) | 1,435 (76.9) | 15,143 (77.8) |
Alcohol drunk (+) | 2,876 (11.8) | 53 (4.7) | 2,823 (21.6) |
Mean (SD) | |||
Prehospital vital signs | |||
Systolic blood pressure, mmHg | 132.3 (34.6) | 130 (34.8) | 132.5 (34.6) |
Diastolic blood pressure, mmHg | 77.7 (21.3) | 76.7 (21.3) | 77.8 (21.3) |
Respiratory rate, breaths/min | 23.0 (7.5) | 24.9 (8.5) | 22.8 (7.4) |
Heart rate, beats/min | 87.7 (22.6) | 87.7 (23.8) | 87.7 (22.5) |
Japan coma scale | |||
Grade 0 | 5,077 (23.5) | 408 (26.8) | 4,669 (23.3) |
Grade 1 | 6,635 (30.7) | 421 (27.6) | 6,214 (30.9) |
Grade 2 | 2,591 (12.0) | 209 (13.7) | 2382 (11.8) |
Grade 3 | 7,333 (33.9) | 487 (31.9) | 6846 (34.0) |
Initial vital signs at ED | |||
Systolic blood pressure, mmHg | 118.8 (51.6) | 119.1 (44.0) | 118.8 (52.2) |
Diastolic blood pressure, mmHg | 73.0 (27.2) | 72.6 (23.8) | 73.0 (27.5) |
Respiratory rate, breaths/min | 20.8 (9.9) | 22.2 (9.5) | 20.6 (9.9) |
Heart rate, beats/min | 82.1 (33.2) | 85.9 (29.7) | 81.8 (33.5) |
Glasgow coma scale score | 10.9 (4.6) | 10.9 (4.7) | 10.9 (4.6) |
Eye score | 2.8 (1.3) | 2.8 (1.3) | 2.8 (1.3) |
Verbal score | 3.4 (1.7) | 3.7 (1.6) | 3.4 (1.7) |
Motor score | 4.7 (1.9) | 4.7 (2.0) | 4.7 (1.9) |
Japan coma scale | |||
Grade 0 | 5,191 (26.5) | 540 (30.1) | 4,651 (26.1) |
Grade 1 | 5,127 (26.1) | 407 (22.7) | 4,720 (26.5) |
Grade 2 | 2,990 (15.2) | 260 (14.5) | 2,730 (15.3) |
Grade 3 | 6,304 (32.1) | 588 (32.8) | 5,716 (32.1) |
Body temperature, °C | 36.0 (1.1) | 36.0 (1.1) | 36.0 (1.1) |
Results
Patients by transportation method, n(%) | |||
---|---|---|---|
All patients, n(%) | Helicopter | Ground | |
(N = 24,293) | (N = 2,090) | (N = 22,203) | |
Neurological diseases | |||
Psychotic disorders | 1,620 (6.7) | 71 (3.4) | 1,549 (7.0) |
Dementia or mental retardation | 479 (2.0) | 21 (1.0) | 458 (2.1) |
Lung diseases | |||
Bronchial asthma | 564 (2.3) | 55 (2.6) | 509 (2.3) |
COPD | 101 (0.4) | 9 (0.4) | 92 (0.4) |
Cardiovascular diseases | |||
Stroke | 779 (3.2) | 59 (2.8) | 720 (3.2) |
Coronary heart disease | 551 (2.3) | 48 (2.3) | 503 (2.3) |
Congestive heart failure | 221 (0.9) | 12 (0.6) | 209 (0.9) |
Hypertension | 3,310 (13.6) | 294 (14.1) | 3,016 (13.6) |
Digestive diseases | |||
Peptic ulcer | 428 (1.8) | 40 (1.9) | 388 (1.7) |
Chronic hepatitis | 314 (1.3) | 19 (0.9) | 295 (1.3) |
Cirrhosis | 183 (0.8) | 13 (0.6) | 170 (0.8) |
IBD | 106 (0.4) | 16 (0.8) | 90 (0.4) |
Systemic diseases or diseases of other organs | |||
Diabetes | 1,666 (6.9) | 132 (6.3) | 1,534 (6.9) |
Dialysis | 180 (0.7) | 13 (0.6) | 167 (0.8) |
Active cancer | 314 (1.3) | 34 (1.6) | 280 (1.3) |
Marked obesity | 38 (0.2) | 4 (0.2) | 34 (0.2) |
Hematologic disorders | 43 (0.2) | 4 (0.2) | 39 (0.2) |
HIV infection | 13 (0.1) | 0 (0.0) | 13 (0.1) |
Pregnancy | 15 (0.1) | 1 (0.0) | 14 (0.1) |
Medications | |||
Anticoagulant | 194 (0.8) | 16 (0.8) | 178 (0.8) |
Steroid | 48 (0.2) | 3 (0.1) | 45 (0.2) |
Immunosuppressant | 14 (0.1) | 2 (0.1) | 12 (0.1) |
Previously healthy | 1,4696 (60.5) | 13,406 (60.4) | 1,290 (61.7) |
Patients by transportation method, n(%) | |||
---|---|---|---|
All patients, n (%) | Helicopter | Ground | |
(N = 24,293) | (N = 2,090) | (N = 22,203) | |
Prehospital treatment | |||
O2
| 17,110 (70.4) | 1,475 (70.6) | 15,635 (70.4) |
Cervical collar | 14,611 (60.1) | 1,259 (60.2) | 13,352 (60.1) |
Backboard | 14,181 (58.4) | 1,349 (64.5) | 12,832 (57.8) |
Shock pants | 21 (0.1) | 2 (0.1) | 19 (0.1) |
Splint | 309 (1.3) | 22 (1.1) | 287 (1.3) |
Intubation | 1,840 (7.6) | 121 (5.8) | 1,719 (7.7) |
Nasal airway tube | 240 (1.0) | 10 (0.5) | 230 (1.0) |
Airway protection maneuver | 2,023 (8.3) | 233 (11.1) | 1,790 (8.1) |
Intravenous fluid | 963 (4.0) | 395 (18.9) | 568 (2.6) |
FAST at ED | |||
Positive | 2,919 (12.7) | 309 (15.4) | 2,610 (12.4) |
Negative | 16,598 (71.9) | 1,559 (77.8) | 15,039 (71.4) |
Not used | 3,557 (15.4) | 136 (6.8) | 3,421 (16.2) |
CT | |||
Head | 20,473 (84.3) | 1,708 (81.7) | 18,765 (84.5) |
Neck | 12,246 (50.4) | 1,138 (54.4) | 11,108 (50.0) |
Spine | 4,845 (19.9) | 485 (23.2) | 4,360 (19.6) |
Chest | 16,155 (66.5) | 1,577 (75.5) | 14,578 (65.7) |
Abdomen | 15,376 (63.3) | 1,502 (71.9) | 13,874 (62.5) |
Pelvis | 12,424 (51.1) | 1,006 (48.1) | 11,418 (51.4) |
Others | 899 (3.7) | 72 (3.4) | 827 (3.7) |
Angiography | |||
Head | 298 (1.2) | 27 (1.3) | 271 (1.2) |
Neck | 131 (0.5) | 12 (0.6) | 119 (0.5) |
Spine | 46 (0.2) | 4 (0.2) | 42 (0.2) |
Chest | 335 (1.4) | 36 (1.7) | 299 (1.3) |
Abdomen | 1,190 (4.9) | 119 (5.7) | 1,071 (4.8) |
Pelvis | 1,215 (5.0) | 143 (6.8) | 1,072 (4.8) |
Others | 81 (0.3) | 12 (0.6) | 69 (0.3) |
Blood transfusion (+) | 6,611 (28.0) | 782 (38.2) | 5,829 (27.0) |
Operation | |||
Craniotomy | 2,055 (8.5) | 142 (6.8) | 1,913 (8.6) |
Craterization | 716 (2.9) | 36 (1.7) | 680 (3.1) |
Throracotomy | 947 (3.9) | 130 (6.2) | 817 (3.7) |
Celiotomy | 1,427 (5.9) | 177 (8.5) | 1,250 (5.6) |
Bone fixation | 3,606 (14.8) | 432 (20.7) | 3,174 (14.3) |
Angiostomy | 68 (0.3) | 6 (0.3) | 62 (0.3) |
TAE | 1,237 (5.1) | 127 (6.1) | 1,110 (5.0) |
Endoscopic surgery | 23 (0.1) | 3 (0.1) | 20 (0.1) |
Anastomosis | 9 (0.0) | 1 (0.0) | 8 (0.0) |
Others | 959 (3.9) | 93 (4.4) | 866 (3.9) |
Disposition at ED | |||
Died | 2,004 (8.2) | 1,877 (8.5) | 127 (6.1) |
ICU | 18,439 (75.9) | 1,634 (78.2) | 16,805 (75.7) |
Ward | 3,197 (13.2) | 184 (8.8) | 3,013 (13.6) |
Others | 452 (1.9) | 139 (6.7) | 313 (1.4) |
Disposition at discharge | |||
Died | 6,311 (26.0) | 546 (26.1) | 5,765 (26.0) |
Hospital transfer | 10,172 (41.9) | 1,063 (50.9) | 9,109 (41.0) |
Home | 7,810 (32.1) | 481 (23.0) | 7,329 (33.0) |
Survival OR (95% CI) | ||
---|---|---|
Analysis | At discharge | At ED |
Crude (N = 24,293) | 0.992 (0.895 to 1.098) | 1.437 (1.193 to 1.730) |
Unconditional logistic regression | ||
Standard (n = 15,382) | 1.277 (1.049 to 1.556) | 1.141 (0.729 to 1.785) |
After propensity score matchingb (n = 2,510) | 1.446 (1.220 to 1.714) | 2.367 (1.822 to 3.075) |
Conditional logistic regression (n = 2,510) | 1.230 (1.017 to 1.488) | 1.703 (1.255 to 2.311) |
Patients by transportation method, n(%) | |||
---|---|---|---|
Helicopter | Ground | ||
(N = 1,255) | (N = 1,255) | SDa(%) | |
Males | 949 (75.6) | 918 (73.3) | 5.3% |
Age, yr | 55.2 (19.5) | 54.4 (20.8) | 4.0% |
Injury type | |||
Blunt | 1,239 (98.7) | 1,240 (98.8) | 0.9% |
Penetrating | 16 (1.3) | 15 (1.2) | |
Cause of injury | |||
Motor vehicle crashes | 656 (54.2) | 613 (54.1) | 9.8% |
Falls | 415 (34.3) | 450 (39.7) | 11.2% |
Other reasons | 139 (11.5) | 70 (6.2) | 18.7% |
Injury severity score | 27.5 (12.6) | 28.3 (14.4) | 5.9% |
Prehospital vital signs | |||
Systolic blood pressure, mmHg | 131.6 (86.9) | 133.8 (36.2) | 3.3% |
Respiratory rate, breaths/min | 23.5 (5.5) | 22.8 (5.5) | 12.7% |
Heart rate, beats/min | 86.9 (23.9) | 87.0 (20.9) | 0.4% |
Prehospital treatment | |||
Intubation | 70 (5.6) | 164 (13.1) | 26.0% |
Airway protection maneuver | 124 (9.9) | 133 (10.6) | 1.6% |
Intravenous fluid | 217 (17.3) | 38 (3.0) | 48.7% |
Discussion
Study | Number of patients | OR (95% CI) for HEMS survival |
---|---|---|
Thomas et al. [7] | ||
HEMS | 2,292 | 1.32 (1.03 to 1.71) |
GEMS | 14,407 | |
Brown et al. [8] | 1.22 (1.18 to 1.27) | |
HEMS | 41,987 | |
GEMS | 216,400 | |
Stewart et al. [9] | ||
HEMS | 2,739 | 1.49 (1.19 to 1.89) |
GEMS | 6,473 | |
Sullivant et al. [10] | ||
HEMS | 10,049 | 1.64 (1.45 to 1.87) |
GEMS | 46,695 | |
Galvagno et al. [2] | ||
HEMS | 47,637 | 1.16 (1.14 to 1.17) |
GEMS | 111,874 | |
Andruszkow et al. [1] | ||
HEMS | 4,989 | 1.33 (1.16 to 1.57) |
GEMS | 8,231 | |
Present study (2014) | ||
HEMS | 2,090 | 1.23 (1.02 to 1.49) |
GEMS | 22,203 |
Conclusion
Key messages
-
We add robust results to previously published data on the relative benefits of HEMS compared to GEMS based on our rigorous analytical methods after controlling for multiple known confounders.
-
HEMS demonstrated a survival benefit compared to GEMS, although HEMS patients had more serious medical conditions.