. 2017 Oct 24;318(16):1581–1591. doi: 10.1001/jama.2017.15097

Table 2. Characteristics After Hospital Arrival of US Military Combat Casualties Who Received or Did Not Receive Prehospital Transfusion.

Characteristics	Prehospital Transfusion Recipients, Median (IQR) (n = 55)^a	Matched Nonrecipients, Median (95% CI) (n = 345)^a^,^b	P Value
Time from injury occurrence to arrival at first surgical hospital, min
No. of patients without missing data	54	334
Value	48 (37 to 59)	46.9 (43.7 to 50.0)	.70
MEDEVAC transport time, min
No. of patients without missing data	55	333
Value	17 (15 to 22)	16.4 (13.2 to 19.5)	.70
Received tranexamic acid, No. (%) [95% CI]	48 (87)	155 (45) [22 to 71]	<.001
Initially transported to a role 3 surgical hospital, No. (%) [95% CI]^c	48 (87)	192 (63) [39 to 81]^d	.004
Emergency department laboratory values
Base deficit, mEq/L
No. of patients without missing data	52	249^d
Value	−7 (−11 to −4)	−6.2 (−7.9 to −4.4)	.37
pH
No. of patients without missing data	53	257^d
Value	7.28 (7.17 to 7.38)	7.29 (7.24 to 7.34)	.65
Hemoglobin, g/dL
No. of patients without missing data	51	261^d
Value	12.4 (10.9 to 13.7)	12.8 (11.4 to 13.4)	.24
International normalized ratio
No. of patients without missing data	34	210^d
Value	1.4 (1.2 to 1.7)	1.26 (1.16 to 1.36)	.008
Total RBCs or whole blood by hour 24 after hospital admission, U
No. of patients without missing data	55	186^d^,^e
Value	15 (8 to 23)	11.0 (8.5 to 13.5)	.002
Total length of hospital stay among survivors at day 30, d
No. of patients without missing data	48^f	265^f
Value	30 (21 to 30)	30 (27 to 33)	>.99
Maximum Abbreviated Injury Scale (AIS) score^g	4 (3 to 5)	4.0 (3.6 to 4.4)	.90
Injury Severity Score (ISS)^h	29 (17 to 36)	28.6 (24.0 to 33.2)	.88

Abbreviations: IQR, interquartile range; MEDEVAC, medical evacuation; RBCs, red blood cells.

^{^a}

Unless otherwise indicated.

^{^b}

Adjusted estimates from median and logistic regression adjusted simultaneously for the matching factors of (1) mechanism of injury, (2) prehospital shock, (3) type and severity of traumatic limb amputation, (4) hemorrhagic torso injury assessed by AIS diagnostic code, and (5) severity of head injury assessed by maximum head AIS score and for the 5 covariates of age, minutes from injury occurrence to MEDEVAC rescue, injury year, transport team, and prehospital tourniquet use.

^{^c}

Patients were transported to either a role 3 military hospital providing definitive theater support and advanced capabilities or a role 2 military surgical facility providing forward resuscitative care with limited resources.

^{^d}

Of the 304 nonrecipients who survived to receive treatment in the emergency department of the first surgical hospital.

^{^e}

There were 186 nonrecipients who received an initial transfusion during hospitalization.

^{^f}

Of the 49 recipients and 267 nonrecipients who were discharged alive or survived through hospital day 30.

^{^g}

Ranges from 0 (no injury) to 6 (not survivable) for each of 6 body regions (head, face, chest, abdomen, extremities, and external).

^{^h}

Computed as the sum of the squares of each AIS score for the 3 most severely injured body regions. If any AIS score is 6, the maximum ISS of 75 is assigned.