Reliability of mechanical ventilation during continuous chest compressions: a crossover study of transport ventilators in a human cadaver model of CPR

TY - JOUR

T1 - Reliability of mechanical ventilation during continuous chest compressions

T2 - a crossover study of transport ventilators in a human cadaver model of CPR

AU - Orlob, Simon

AU - Wittig, Johannes

AU - Hobisch, Christoph

AU - Auinger, Daniel

AU - Honnef, Gabriel

AU - Fellinger, Tobias

AU - Ristl, Robin

AU - Schindler, Otmar

AU - Metnitz, Philipp

AU - Feigl, Georg

AU - Prause, Gerhard

N1 - Funding Information: This study was funded by the Austrian Association of Emergency and Disaster Medicine (abbr.: ÖNK) with the “Reinhard Malzer Award”. However, the association did not interfere with any steps towards this paper. Open Access funding enabled and organized by Projekt DEAL. Funding Information: First and foremost, we thank all body donors for their invaluable donations to science and education. We want to thank Jan Wnent, Theresa Berthold, Paul Zajic, Gregor Schittek, Andreas Sandner-Kiesling, Aidan Baron, and Angela Poli-Sch?pfer for careful review of the manuscript. Especially we thank Otto Touzil for programming the drivers for the used sensors. We would like to thank the Austrian Association of Emergency and Disaster Medicine (abbr.: ?NK) and Medizinercorps Graz Alumni for making this research possible. Publisher Copyright: © 2021, The Author(s).

PY - 2021/12

Y1 - 2021/12

N2 - Background: Previous studies have stated that hyperventilation often occurs in cardiopulmonary resuscitation (CPR) mainly due to excessive ventilation frequencies, especially when a manual valve bag is used. Transport ventilators may provide mandatory ventilation with predetermined tidal volumes and without the risk of hyperventilation. Nonetheless, interactions between chest compressions and ventilations are likely to occur. We investigated whether transport ventilators can provide adequate alveolar ventilation during continuous chest compression in adult CPR. Methods: A three-period crossover study with three common transport ventilators in a cadaver model of CPR was carried out. The three ventilators ‘MEDUMAT Standard²’, ‘Oxylog 3000 plus’, and ‘Monnal T60’ represent three different interventions, providing volume-controlled continuous mandatory ventilation (VC-CMV) via an endotracheal tube with a tidal volume of 6 mL/kg predicted body weight. Proximal airflow was measured, and the net tidal volume was derived for each respiratory cycle. The deviation from the predetermined tidal volume was calculated and analysed. Several mixed linear models were calculated with the cadaver as a random factor and ventilator, height, sex, crossover period and incremental number of each ventilation within the period as covariates to evaluate differences between ventilators. Results: Overall median deviation of net tidal volume from predetermined tidal volume was − 21.2 % (IQR: 19.6, range: [− 87.9 %; 25.8 %]) corresponding to a tidal volume of 4.75 mL/kg predicted body weight (IQR: 1.2, range: [0.7; 7.6]). In a mixed linear model, the ventilator model, the crossover period, and the cadaver’s height were significant factors for decreased tidal volume. The estimated effects of tidal volume deviation for each ventilator were − 14.5 % [95 %-CI: −22.5; −6.5] (p = 0.0004) for ‘Monnal T60’, − 30.6 % [95 %-CI: −38.6; −22.6] (p < 0.0001) for ‘Oxylog 3000 plus’ and − 31.0 % [95 %-CI: −38.9; −23.0] (p < 0.0001) for ‘MEDUMAT Standard²’. Conclusions: All investigated transport ventilators were able to provide alveolar ventilation even though chest compressions considerably decreased tidal volumes. Our results support the concept of using ventilators to avoid excessive ventilatory rates in CPR. This experimental study suggests that healthcare professionals should carefully monitor actual tidal volumes to recognise the occurrence of hypoventilation during continuous chest compressions.

AB - Background: Previous studies have stated that hyperventilation often occurs in cardiopulmonary resuscitation (CPR) mainly due to excessive ventilation frequencies, especially when a manual valve bag is used. Transport ventilators may provide mandatory ventilation with predetermined tidal volumes and without the risk of hyperventilation. Nonetheless, interactions between chest compressions and ventilations are likely to occur. We investigated whether transport ventilators can provide adequate alveolar ventilation during continuous chest compression in adult CPR. Methods: A three-period crossover study with three common transport ventilators in a cadaver model of CPR was carried out. The three ventilators ‘MEDUMAT Standard²’, ‘Oxylog 3000 plus’, and ‘Monnal T60’ represent three different interventions, providing volume-controlled continuous mandatory ventilation (VC-CMV) via an endotracheal tube with a tidal volume of 6 mL/kg predicted body weight. Proximal airflow was measured, and the net tidal volume was derived for each respiratory cycle. The deviation from the predetermined tidal volume was calculated and analysed. Several mixed linear models were calculated with the cadaver as a random factor and ventilator, height, sex, crossover period and incremental number of each ventilation within the period as covariates to evaluate differences between ventilators. Results: Overall median deviation of net tidal volume from predetermined tidal volume was − 21.2 % (IQR: 19.6, range: [− 87.9 %; 25.8 %]) corresponding to a tidal volume of 4.75 mL/kg predicted body weight (IQR: 1.2, range: [0.7; 7.6]). In a mixed linear model, the ventilator model, the crossover period, and the cadaver’s height were significant factors for decreased tidal volume. The estimated effects of tidal volume deviation for each ventilator were − 14.5 % [95 %-CI: −22.5; −6.5] (p = 0.0004) for ‘Monnal T60’, − 30.6 % [95 %-CI: −38.6; −22.6] (p < 0.0001) for ‘Oxylog 3000 plus’ and − 31.0 % [95 %-CI: −38.9; −23.0] (p < 0.0001) for ‘MEDUMAT Standard²’. Conclusions: All investigated transport ventilators were able to provide alveolar ventilation even though chest compressions considerably decreased tidal volumes. Our results support the concept of using ventilators to avoid excessive ventilatory rates in CPR. This experimental study suggests that healthcare professionals should carefully monitor actual tidal volumes to recognise the occurrence of hypoventilation during continuous chest compressions.

KW - Artificial respiration

KW - Cardiac arrest

KW - Cardiopulmonary resuscitation

KW - Out-of-hospital cardiac arrest

KW - Reversed airflow

KW - Tidal volume

KW - Ventilators, mechanical

UR - http://www.scopus.com/inward/record.url?scp=85111524519&partnerID=8YFLogxK

U2 - 10.1186/s13049-021-00921-2

DO - 10.1186/s13049-021-00921-2

M3 - Journal article

C2 - 34321068

AN - SCOPUS:85111524519

SN - 1757-7241

VL - 29

JO - Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine

JF - Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine

IS - 1

M1 - 102

ER -