Minimum oxygen flow needed for vital support during simulated post-cardiorespiratory arrest resuscitation

Abstract

According to the ERC and the AHA guidelines, FiO2 should be titrated to achieve an O2Sat ≥ 94%. The aim of this study was to determine the minimum oxygen flow and time needed to reach an FiO2 of 0.32 and 0.80 during post-cardiac arrest care. An experimental analysis was performed that consisted of a simulated post-cardiac arrest situation. Different resuscitators were tested and connected to an artificial lung: Mark IV, SPUR II, Revivator Res-Q, O-TWO. The oxygen flow levels tested were 2, 5, 10 and 15 lpm. Bonferroni and Mann-Whitney U tests were used. An FiO2 of 0.32 or more was obtained using any of the oxygen flow and resuscitators. Only the Mark IV achieved an FiO2 of 0.80 after a minimum of 75s ventilating with 2 or 5 lpm. Clinical and statistical differences (P<.05) were found: at 15 lpm it took 35s to reach an FiO2 of 0.80 or more for Mark IV (85.6 [0.3]) and Revivator (84.3 [1.5]) compared to 50s for SPUR II (87.1 [6.4]); at 2 lpm, all of the devices reached an FiO2 of ≥ 0.32 at 30s(Mark IV (34.8 [1.3]), Revivator (35.7 [1.5]) and SPUR II (34.4 [2.1]), except for O-TWO, which took 35s (36.3 [4.3]). Patients could be ventilated with any of the resuscitators using 2 lpm to obtain an FiO2 of 0.32, although possibly O-TWO would be the last option during the first 60s. In order to reach an FiO2 of 0.80, ventilating with 10 lpm should be sufficient, and preferably using Mark IV or Revivator Res-Q. In conclusion, on observing the results of our study, in any possible scenario, it would be advisable to use Revivator Res-Q or Mark IV rather than O-TWO or SPUR II.

Keywords: Bag valve mask device; Cardiopulmonary resuscitation; Fracción inspirada de oxígeno; Fraction of inspired oxygen; Reanimación cardiopulmonar; Resucitador.