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Table 10 Performance of various values of PetCO2 and duration of CPR for prediction of survival in patients with nonshockable initial rhythm in cardiac arrest

From: Partial pressure of end-tidal carbon dioxide successful predicts cardiopulmonary resuscitation in the field: a prospective observational study

PetCO2 Cut-off (kPa [mmHg]) n Min-max (kPa [mmHg]) Mean ± SD (kPa [mmHg]) Sensitivity (%) Specificity (%) PPV (%) NPV (%) AUROC (95% CI)
initial ≤1.3 (10) 97 0.0–1.3 (0.0–10) 0.66 ± 0.32 (5.1 ± 1.9) 100 27 23 100 0.58 (0.52–0.63)
  >1.3 (10) 336 1.4–8.4 (10.1–63.2) 4.17 ± 2.12 (30.9 ± 15.8)      
0–10 min ≤1.7 (12.8) 229 0.4–1.7 (3.5–12.8) 0.99 ± 0.36 (7.1 ± 3.3) 100 64 37 100 0.88 (0.84–0.91)
  >1.7 (12.8) 204 1.8–5.6 (12.9–42.1) 2.79 ± 0.86 (21.5 ± 6.2)      
10 min ≤1.6 (12.1) 199 0.3–1.6 (2.2–12.1) 1.03 ± 0.38 (7.6 ± 3.1) 100 56 32 100 0.87 (0.83–0.91)
  >1.6 (12.1) 234 1.7–7.2 (12.2–54.2) 3.02 ± 1.08 (22.6 ± 6.5)      
11–15 min ≤1.7 (12.8) 239 0.4–1.7 (3.4–12.8) 0.99 ± 0.31 (7.3 ± 2.8) 100 67 39 100 0.86 (0.83–0.90)
  >1.7 (12.8) 194 1.4–5.1 (12.9–38.4) 3.14 ± 0.81 (23.3 ± 6.7)      
15 min ≤1.9 (14.3) 241 0.3–1.9 (2.4–14.3) 1.12 ± 0.41 (7.9 ± 3.8) 100 67 39 100 0.87 (0.84–0.91)
  >1.9 (14.3) 192 2.1–6.1 (14.4–45.9) 3.62 ± 0.94 (28.6 ± 7.5)      
20 min ≤2.1 (15.8) 242 0.3–2.1 (2.3–15.8) 0.91 ± 0.31 (7.2 ± 2.2) 100 68 40 100 0.87 (0.84.0.91)
  >2.1 (15.8) 190 2.3–7.8 (15.9–58.7) 4.39–1.11 (33.1 ± 7.7)      
max ≤2.8 (21.1) 231 0.8–2.8 (6.1–21.1) 1.68 ± 0.44 (13.4 ± 3.5) 100 65 38 100 0.89 (0.86–0.92)
  >2.8 (21.1) 202 2.9–10.7 (21–80.5) 5.26 ± 1.48 (39.1 ± 12.2)      
Final ≤1.6 (12.1) 240 0.2–1.6 (1.9–12.1) 0.97 ± 0.33 (6.9 ± 2.7) 100 67 39 100 0.87 (0.84–0.91)
  >1.6 (12.1) 193 1.9–6.6 (12.2–49.6) 3.06 ± 0.97 (27.1 ± 7.2)      
  1. 'Nonshockable' was defined as asystole or pulseless electrical activity. AUROC, area under the receiver operating characteristic curve; CI, confidence interval; CPR, cardiopulmonary resuscitation; NPV, negative predictive value; PetCO2, partial pressure of end-tidal carbon dioxide; PPV, positive predictive value; ROSC, restoration of spontaneous circulation; SD, standard deviation.