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Table 1 Descriptive characteristics

From: Associations of arterial carbon dioxide and arterial oxygen concentrations with hospital mortality after resuscitation from cardiac arrest

Characteristic   All patients PaCO2 group   PaO2 group  
  Hypocapnia Normocapnia Hypercapnia P value Hypoxia Normoxia Hyperoxia P value
No. (%) of patients 5258 1136 (21.6) 2288 (43.5) 1834 (34.9)   418 (8.0) 4696 (89.3) 144 (2.7)  
Baseline characteristics          
Age (years) 66 (56–76) 68 (56–77) 66 (56–76) 65 (55–74) <0.001 69 (57–78) 66 (56–75) 67 (56–77) 0.02
Male gender, n (%) 3661 (69.6) 737 (64.9) 1601 (70.0) 1323 (72.1) <0.001 294 (70.3) 3269 (69.6) 98 (68.1) 0.87
Admission source, n (%)          
 Operating room from emergency room same hospital 182 (3.5) 32 (2.8) 95 (4.2) 55 (3.0) 0.05 14 (3.3) 166 (3.5) 2 (1.4) 0.38
 Emergency room same hospital 4578 (87.1) 981 (86.4) 1972 (86.2) 1625 (88.6) 0.05 367 (87.8) 4077 (86.8) 134 (93.1) 0.08
 Operating room from emergency room other hospital 4 (0.1) 1 (0.1) 1 (<0.1) 2 (0.1) 0.74 0 4 (0.1) 0 0.79
 Emergency room other hospital 183 (3.5) 41 (3.6) 81 (3.5) 61 (3.3) 0.90 16 (3.8) 166 (3.5) 1 (0.7) 0.17
 Home 311 (5.9) 81 (7.1) 139 (6.1) 91 (5.0) 0.05 21 (5.0) 283 (6.0) 7 (4.9) 0.61
Acute renal failure, n (%) 660 (12.6) 154 (13.6) 242 (10.6) 264 (14.4) <0.001 79 (18.9) 565 (12.0) 16 (11.1) <0.001
Chronic co-morbidities, n (%)          
 Cardiovascular disease 380 (7.2) 94 (8.3) 158 (6.9) 128 (7.0) 0.30 30 (7.2) 340 (7.2) 10 (6.9) 0.99
 Renal disease 319 (6.1) 87 (7.7) 137 (6.0) 95 (5.2) 0.04 24 (5.7) 287 (6.1) 8 (5.6) 0.91
 Respiratory disease 225 (4.3) 33 (2.9) 72 (3.1) 120 (6.5) <0.001 26 (6.2) 191 (4.1) 8 (5.6) 0.08
 Cirrhosis 44 (0.8) 16 (1.4) 14 (0.6) 14 (0.8) 0.05 9 (2.2) 35 (0.7) 0 <0.01
 Cancer 106 (2.0) 25 (2.2) 48 (2.1) 33 (1.8) 0.62 6 (1.4) 96 (2.0) 4 (2.8) 0.57
Markers of severity,          
 APACHE IV score 117.3 (29.69) 117.5 (29.10) 114.6 (30.52) 120.4 (28.68) <0.001 132.2 (29.22) 115.9 (29.47) 119.5 (26.21) <0.001
 APACHE IV risk of death 80.7 (65.3-90.0) 81.2 (66.2-90.2) 79.2 (63.0-89.2) 82.5 (68.2-91.1) <0.001 88.8 (78.1-94.0) 79.8 (64.3-89.4) 81.9 (64.9-89.4) <0.001
Physiological parameters obtained within the first 24 h in the intensive care unit     
Temperature          
 Highest temperature (°C) 35.7 (34.8-36.9) 35.8 (34.7-37.0) 35.7 (34.8-36.8) 35.8 (34.8-36.9) 0.37 35.7 (34.6-37.1) 35.7 (34.8-36.9) 35.9 (34.9-36.8) 0.88
 Lowest temperature (°C) 32.5 (31.8-33.2) 32.4 (31.8-33.4) 32.5 (31.9-33.2) 32.5 (31.9-33.3) 0.55 32.5 (31.8-33.6) 32.5 (31.8-33.2) 32.4 (31.7-33.3) 0.78
Lowest temperature below 34 °C, n (%) 4229 (80.4) 888 (78.2) 1863 (81.4) 1478 (80.6) 0.08 326 (78.0) 3788 (80.7) 115 (79.9) 0.41
Heart Rate          
 Highest heart rate, beats/min 103 (87–120) 102 (85–120) 101 (86–119) 105 (90–122) <0.001 110 (91–128) 102 (87–120) 105 (88–125) <0.001
 Lowest heart rate, beats/min 55 (45–68) 55 (45–69) 53 (44–65) 55 (45–70) <0.001 55 (45–74) 55 (45–67) 51 (42–67) 0.11
Blood pressure (BP)          
 Highest systolic BP (mmHg) 150 (134–171) 150 (134–170) 150 (134–172) 150 (133–170) 0.61 145 (128–165) 150 (134–172) 156 (139–178) <0.001
 Lowest systolic BP (mmHg) 80 (70–90) 80 (71–91) 81 (70–90) 80 (69–89) <0.001 76 (64–86) 80 (70–90) 82 (70–91) <0.001
Respiratory rate (RR)          
 Highest RR, breaths (min) 23 (20–28) 23 (19–29) 23 (19–28) 24 (20–29) <0.001 25 (20–30) 23 (20–28) 23 (19–28) <0.01
 Lowest RR, breaths (min) 14 (12–16) 14 (12–16) 14 (11–16) 14 (12–17) 0.03 15 (12–18) 14 (12–16) 14 (12–16) <0.001
Oxygenation          
 PaO2 (mmHg) 92 (75–124) 99 (78–136) 94 (76–125) 87 (70–116) <0.001 51 (44–56) 94 (78–124) 359 (320–438) <0.001
 FiO2 (%) 50 (40–70) 45 (40–60) 50 (40–62) 60 (44–90) <0.001 66 (50–100) 50 (40–70) 98 (67–100) <0.001
 PaO2/FiO2 ratio 191 (124–272) 227 (157–316) 203 (134–283) 158 (100–228) <0.001 71 (55–100) 198 (136–272) 440 (361–550) <0.001
Carbon dioxide          
 PaCO2 (mmHg) 42 (36–49) 31 (28–33) 40 (38–43) 52 (48–59) <0.001 45 (38–54) 41 (35–48) 40 (34–48) <0.001
Metabolic          
 Lowest glucose (mmol l−1) 6.0 (4.8-7.4) 5.9 (4.8-7.3) 6.0 (4.8-7.3) 6.1 (4.8-7.5) 0.65 6.2 (4.8-7.9) 6.0 (4.8-7.3) 6.1 (5.0-7.8) 0.13
Acid–base balance          
 Lowest pH 7.28 (0.12) 7.37 (0.11) 7.30 (0.10) 7.20 (0.12) <0.001 7.24 (0.14) 7.29 (0.12) 7.26 (0.14) <0.001
 Highest HCO3 - (mmol l−1) 22.3 (3.92) 20.8 (3.67) 22.1 (3.54) 23.5 (4.16) <0.001 22.8 (4.70) 22.3 (3.85) 22.0 (3.89) 0.43
 Lowest HCO3 - (mmol l−1) 17.4 (4.33) 16.0 (4.17) 17.4 (4.03) 18.3 (4.54) <0.001 16.6 (4.96) 17.5 (4.27) 17.2 (4.10) <0.01
  1. Data presented as total number (percentage), mean (standard deviation) or median (interquartile range) depending on underlying data distribution
  2. P-values for group comparisons using ANOVA or Kruskal-Wallis according to data distribution
  3. APACHE Acute Physiology and Chronic Health Evaluation, ANOVA Analysis of variance