Jun Xu1, Xuezhong Yu2, Lili Zhang3, Yangyang Fu3, Kui Jin3, Lu Yin3, Shanshan Yu3, Danyu Liu3. 1. Emergency Department, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China. Electronic address: xujunfree@126.com. 2. Emergency Department, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China. Electronic address: yxzpumch@126.com. 3. Emergency Department, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China.
Abstract
AIM: We aimed to investigate whether the ability of the volumetric capnography-derived parameter, the volume of CO2 eliminated per minute and per kg body weight (V'CO2 kg-1), in monitoring the quality of CPR and predicting the return of spontaneous circulation (ROSC) remains undisturbed by hyperventilation. METHODS: This randomised crossover study included 12 male domestic pigs. After 4 min of untreated ventricular fibrillation, mechanical CPR was administered. Following 5-min washout periods, each animal underwent two sessions of experiments; four 5-min ventilation trials followed by advanced life support, consecutively in the two sessions. RESULTS: Different ventilation types had no significant impact on V'CO2 kg-1 or haemodynamics. However, PETCO2 was significantly affected by the ventilation type and coronary perfusion pressure (P < 0.05). The means ± standard deviations of PETCO2 decreased linearly with an increase in the respiratory rate (RR) (P < 0.05). The PETCO2 decreased from 20.42 ± 9.51 to 16.16 ± 5.07 (P < 0.05) as the tidal volume increased from 10 to 20 mL min-1. No significant differences in V'CO2 kg-1 were observed between the three RR levels of ventilation types (P = 0.274). Post hoc analysis demonstrated a significant difference between the highest value of V'CO2 kg-1 in double tidal volume hyperventilation and normal ventilation and triple respiratory rate hyperventilation (P < 0.05). The AUC for V'CO2 kg-1 and PETCO2 in discriminating between survivors and non-survivors was 0.80 and 0.71, respectively. CONCLUSIONS: V'CO2 kg-1 performs better than PETCO2 in monitoring the quality of CPR during hyperventilation. In predicting ROSC during variations in a ventilation state, V'CO2 kg-1 has good predictive ability.
AIM: We aimed to investigate whether the ability of the volumetric capnography-derived parameter, the volume of CO2 eliminated per minute and per kg body weight (V'CO2 kg-1), in monitoring the quality of CPR and predicting the return of spontaneous circulation (ROSC) remains undisturbed by hyperventilation. METHODS: This randomised crossover study included 12 male domestic pigs. After 4 min of untreated ventricular fibrillation, mechanical CPR was administered. Following 5-min washout periods, each animal underwent two sessions of experiments; four 5-min ventilation trials followed by advanced life support, consecutively in the two sessions. RESULTS: Different ventilation types had no significant impact on V'CO2 kg-1 or haemodynamics. However, PETCO2 was significantly affected by the ventilation type and coronary perfusion pressure (P < 0.05). The means ± standard deviations of PETCO2 decreased linearly with an increase in the respiratory rate (RR) (P < 0.05). The PETCO2 decreased from 20.42 ± 9.51 to 16.16 ± 5.07 (P < 0.05) as the tidal volume increased from 10 to 20 mL min-1. No significant differences in V'CO2 kg-1 were observed between the three RR levels of ventilation types (P = 0.274). Post hoc analysis demonstrated a significant difference between the highest value of V'CO2 kg-1 in double tidal volume hyperventilation and normal ventilation and triple respiratory rate hyperventilation (P < 0.05). The AUC for V'CO2 kg-1 and PETCO2 in discriminating between survivors and non-survivors was 0.80 and 0.71, respectively. CONCLUSIONS: V'CO2 kg-1 performs better than PETCO2 in monitoring the quality of CPR during hyperventilation. In predicting ROSC during variations in a ventilation state, V'CO2 kg-1 has good predictive ability.
Keywords:
Cardiac arrest; Cardiopulmonary resuscitation; Hyperventilation; Return of spontaneous circulation; The partial pressure of end-tidal CO(2); The volume of CO(2) eliminated per minute and per kg body weight