Table 1
Baseline Characteristics
| Variables | All N=309 | Group I N=169 | Group II N=140 | p-value |
|---|---|---|---|---|
| Age (years), mean(SD) | 31.4(12.4) | 32.2(13.0) | 30.6(11.6) | 0.28 |
| Male gender, N (%) | 293 (94.8) | 164 (97.0) | 129 (92.1) | 0.53 |
| Body Mass Index 9kg/m2), mean(SD) | 23.7(5.3) | 24.5(5.60 | 22.8(4.7) | 0.07 |
| Ideal Body Weight (kg), mean(SD) | 65.0(6.5) | 65.4(6.7) | 64.6(6.4) | .028 |
| Source of admission, N (%) | ||||
| Emergency Department | 260 (84.1) | 147(87.0) | 113 (80.7) | 0.13 |
| Operating Room | 49 (15.9) | 22 (13.0) | 27 (19.3) | |
| Markers of Injury Severity, mean(SD) | ||||
| Injury Severity Score, points | 30.0(7.5) | 29.996.8) | 30.2(8.2) | 0.74 |
| Revised Trauma Score, points | 5.3(1.1) | 5.3(1.2) | 5.4(1.1) | 0.63 |
| Shock Index | 0.86(0.3) | 0.9(0.4) | 0.8(0.3) | 0.19 |
| IMPACT mortality, % | 27.9(17.9) | 29.2(18.7) | 26.5(16.8) | 0.19 |
| IMPACT outcome, % | 41.7(20.5) | 43.1(20.9) | 40.1(19.9) | 0.20 |
| Physiological Parameters, mean(SD) | ||||
| Systolic blood pressure, mmHg | 128.3(26.5) | 128.4(27.4) | 128.1(25.6) | 0.91 |
| MAP, mmHg | 94.4(22.6) | 93.8(23.9) | 95.1(21.1) | 0.60 |
| Heart rate, beats/min | 104.7(28.2) | 106.8(28.7) | 102.2(27.5) | 0.15 |
| Respiratory rate, breaths/min | 24.3(7.0) | 24.7(7.2) | 23.8(6.7) | 0.31 |
| Oxygen saturation, % | 95.7(8.7) | 95.0(10.3) | 96.5(6.3) | 0.12 |
| Temperature, °C | 36.7(0.7) | 36.7(0.7) | 36.7(0.7) | 0.67 |
| CVP, mmHg | 10.7(4.6) | 11.6(5.0) | 9.6(3.8) | 0.01 |
| Arrival GCS | 5.9(2.8) | 5.9(2.9) | 5.9(2.7) | 0.88 |
| GCS 9-12, N(%) | 55(17.8) | 31(18.3) | 25 17.9) | 0.53 |
| GCS ≤ 8, N(%) | 253(81.9) | 138(81.7) | 115(82.1) | |
| Laboratory Parameters, mean(SD) | ||||
| White blood cell count, 109/L | 17.3(6.8) | 17.5(7.3) | 17.1(6.2) | 0.68 |
| Hemoglobin, gm/L | 139.3(25.0) | 0.44(0.07) | 0.41(0.1) | 0.04 |
| Platelets, 109/L | 271.9(90.7) | 274(90.5) | 270(91.3) | 0.70 |
| Sodium, mmol/L | 139.6(4.1) | 139.6(4.2) | 139.7(4.0) | 0.81 |
| Chloride, mmol/L | 108.2(8.6) | 108.5(6.2) | 107.8(10.8) | 0.49 |
| Creatinine, umol/L | 90.1(61.2) | 94.3(78.7) | 85.0(27.9) | 0.18 |
| Lactic Acid, mmol/L | 3.2(2.9) | 3.4(3.0) | 3.0(2.9) | 0.34 |
| AST, U/L | 111.8(163.8) | 135.3(207.0) | 83.9(80.6) | 0.06 |
| ALT, U/L | 81.6(134.1) | 100.4(169.6) | 59.3(66.0) | 0.07 |
| Respiratory and Ventilator Parameters, mean(SD) | ||||
| Tidal volume, mL | 425(37.9) | 427(42.7) | 422(30.8) | 0.24 |
| Tidal volume per IDBW, mL/kg | 6.6(0.8) | 6.6(0.8) | 6.6(0.8) | 0.90 |
| FiO2, % | 0.8(0.3) | 0.8(0.3) | 0.8(0.3) | 0.93 |
| PEEP, mmHg | 5.9(3.2) | 6.1(3.8) | 5.7(2.1) | 0.31 |
| pH | 7.29(0.9) | 7.29(0.1) | 7.29(0.1) | 0.44 |
| PaCO2, mmHg | 4..2(9.3) | 43.8(9.9) | 42.5(8.5) | 0.23 |
| PaO2, mmHg | 228.4(143.4) | 175.8(117.8) | 291.9(146.2) | <0.001 |
| PaO2/FiO2 ratio, | 316(237) | 240(171) | 407.5(272.5) | <0.001 |
| CT Head Findings, N(%) | ||||
| Epidural Hematoma | 26(8.4) | 16(9.5) | 10(7.1) | 0.50 |
| Subdural Hematoma | 125(40.5) | 69(40.8) | 56(40.0) | 0.88 |
| Subarachnoid hemorrhage | 115(37.2) | 67(39.6) | 48(34.3 ) | 0.33 |
| Intraparenchymal Hemorrhage/Contusion | 151(48.9) | 81(47.9) | 70(50.0) | 0.72 |
| Intraventricular Hemorrhage | 46(14.9) | 26(15.4) | 20(14.3) | 0.79 |
| Cerebral Edema | 107(34.6) | 54(32.0) | 53(37.9) | 0.28 |
| Midline Shift ≥5mm | 42(13.6) | 19(11.2) | 23(16.4) | 0.19 |
| Axonal Injury | 20(6.5) | 11(6.5) | 9(6.4) | 0.98 |
| Herniation | 30(9.7) | 15(8.9) | 15(10.7) | 0.59 |
| Normal findings | 50(16.2) | 25(14.8) | 25(17.9) | 0.47 |
| Isolated Head Injury, N (%) | 96(30.1) | 49(29.0) | 47(33.6) | 0.39 |
| Management | ||||
| Fluid balance at 24 hours (mL), mean±SD | 3372(2528) | 3435(2678) | 3298(2343) | 0.64 |
| Blood products (Units), mean(SD) | ||||
| Red blood cells | 2.1(3.9) | 1.8(3.8) | 2.3(3.9) | 0.26 |
| Platelets | 6.2(4.9) | 7.5(5.8) | 5.1(3.6) | 0.05 |
| Fresh frozen plasma | 5.8(4.6) | 6.4(5.1) | 5.3(3.6) | 0.27 |
| Tranexamic acid, N(%) | 50 (29.8) | 45 (32.4) | 0.62 | |
| Vasopressor index, mean(SD) | 3.5(0.7) | 3.5(0.7) | 3.5(0.6) | 0.46 |
| ICP Monitoring, N(%) | 47(15.2) | 22(14.1) | 25(19.2) | 0.24 |
| Hypertonic saline, N(%) | 155(50.2) | 87(59.6) | 68(57.1) | 0.69 |
| Head injury protocol, N(%) | 165(53.4) | 89(86.5) | 76(70.4) | 0.75 |
[i] Group I: non-persistent hyperoxia, included patients that may had an initial PaO2 greater that 120mmHg, but on repeat ABGs within 3 hours of intubation the PaO2 was less than 120mmHg. Group II: the persistent hyperoxia, included patients that had an initial PaO2 greater that 120mmHg and two or more consecutive ABGs with PaO2 greater than 120mmHg within 24-hours of intubation.
SD, standard deviation; IMPACT, The International Mission for Prognosis and Analysis of Clinical Trials; MAP, mean arterial pressure; CVP, central venous pressure; GCS, Glasgow come scale; AST, aspartate transaminase; ALT, alanine transaminase; IDBW, ideal body weight; FiO2, fraction of inspired oxygen PEEP, positive end-expiratory pressure; PaCO2, partial pressure of carbon dioxide; PaO2, partial pressure of oxygen; PaO2/FiO2, ratio of arterial oxygen partial pressure to fractional inspired oxygen; ICP, intracranial pressure.
Table 2
Hospital outcomes for cohort.
| Variables | All N=309 | Group I N=169 | Group II N=140 | p-value |
|---|---|---|---|---|
| ICU Length of stay (days), mean(SD) | 15.9(18.7) | 17.1923.2) | 14.5(11.2) | 0.23 |
| Hospital length of stay (days), mean(SD) | 54.3(76.2) | 60.2(86.5) | 47.2(61.3) | 0.13 |
| Duration on MV (days), mean(SD) | 10.1(8.4) | 10.6(6.3) | 9.5(10.3) | 0.25 |
| Tracheostomy, N (%) | 80 (25.9) | 51 (34.2) | 29 (23.8) | 0.06 |
| ICU mortality, N (%) | 59 (19.1) | 34 (20.1) | 25 (17.9) | 0.62 |
| Hospital mortality, N (%) | 60 (19.4) | 35 (20.7) | 25 (17.9) | 0.53 |
| ICU discharge GCS, mean(SD) | 9.2(4.7) | 8.9(4.8) | 9.5(4.7) | 0.33 |
| Hospital discharge GCS, mean(SD) | 11.1(5.0) | 11.0(5.1) | 11.2(4.9) | 0.70 |
| Hospital discharge GOS, mean(SD) | 3.1(1.2) | 3.1(1.3) | 3.1(1.2) | 0.47 |
| Hospital discharge GOS <4 | 206 (66.7) | 113 (66.9) | 93 (66.4) | 0.92 |
| Hospital discharge GOS ≥4 | 103 (33.3) | 56 (33.1) | 47 (33.6) | 0.94 |
Table 3
Hospital outcomes in subgroup analysis.
| Group I | Group II | P value | Group I | Group II | P value | |
|---|---|---|---|---|---|---|
| GCS <9 | 33 (23.9) | 24 (20.9) | 0.56 | 3.0(1.3) | 3.0(1.2) | 0.92 |
| Isolated TBI | 11 (22.4) | 9 (19.1) | 0.69 | 2.8(1.2) | 3.2(1.3) | 0.94 |
| HIP | 22 (24.7) | 16 (21.1) | 0.58 | 3.0(1.3) | 3.1(1.2) | 0.61 |
| PF ratio <300 | 27 923.1) | 15 (29.4) | 0.38 | 3.0(1.3) | 2.8(1.3) | 0.31 |
| PF ratio>300 | 8 (15.4) | 10 (11.2) | 0.48 | 3.3(1.1) | 3.4(1.0) | 0.58 |
| SAH | 20 (29.9) | 14 (29.2) | 0.94 | 2.7(1.3) | 2.8(1.1) | 0.87 |
| SDH | 21 (30.4) | 15 (26.8) | 0.65 | 2.7(1.3) | 2.9(1.3) | 0.42 |
Fig. 1
Adjusted odd ratio for hospital mortality (A) and Glasgow outcome score ≥4 (B) for persistent hyperoxia and different PaO2 ranges.