Conflict of Interest Declaration
The ILCOR Continuous Evidence Evaluation process is guided by a rigorous ILCOR Conflict of Interest policy. The following Task Force members and other authors were recused from the discussion as they declared a conflict of interest: (none applicable)
The following Task Force members and other authors declared an intellectual conflict of interest and this was acknowledged and managed by the Task Force Chairs and Conflict of Interest committees: (none applicable)
Ristagno G, Nishiyama C, Ikeyama T, Bray J, Smyth M, Kudenchuck P, Johnson N, Masterson S, Nehme Z, Norii T, Perkins GD, Morley PT, Olasveengen TM -on behalf of the International Liaison Committee on Resuscitation Basic Life Support Task Force.
Passive ventilation Consensus on Science with Treatment Recommendations [Internet] Brussels, Belgium: International Liaison Committee on Resuscitation (ILCOR) Basic Life Support Task Force, 2022 Jan x. Available from: http://ilcor.org
The continuous evidence evaluation process for the production of Consensus on Science with Treatment Recommendations (CoSTR) started with a systematic review of basic life support conducted by Ristagno G, Nishiyama C, and Ikeyama T with involvement of clinical content experts. Evidence for adult and literature was sought and considered by the Basic Life Support Task Force. These data were taken into account when formulating the Treatment Recommendations.
The PICOST (Population, Intervention, Comparator, Outcome, Study Designs and Timeframe)
Population: Adults and children with presumed cardiac arrest in any settings
Intervention: Any passive ventilation technique (eg positioning the body, opening the airway, passive oxygen administration, Boussignac tube, constant flow insufflation of oxygen) in addition to chest compression
Comparators: Standard CPR
Outcomes: Survival to hospital discharge with good neurological outcome and survival to hospital discharge were ranked as critical outcomes. Return of spontaneous circulation (ROSC) was ranked as an important outcome.
Study Designs: Randomized controlled trials (RCTs) and non-randomized studies (non-randomized controlled trials, interrupted time series, controlled before-and-after studies, cohort studies) were eligible for inclusion.
Timeframe: All years and all languages were included as long as there was an English abstract; unpublished studies (e.g., conference abstracts, trial protocols) were excluded. Literature search updated to Oct 16th, 2020.
PROSPERO Registration CRD42021293309
NOTE FOR RISK OF BIAS:
Bias was assessed per comparison rather than per outcome, since there were no meaningful differences in bias across outcomes. In cases where differences in risk of bias existed between outcomes this was noted.
Consensus on Science
Two RCTs, one observational study and a very small pilot RCT were identified.(Bertrand 2006 843, Saïssy 2000 1523, Bobrow 2009 656, Fuest 2021 85) The overall quality of evidence was rated as very low. The individual studies were all at a critical risk of bias due to confounding and indirectness. Because of a high degree of heterogeneity, the meta-analyses included only 2 RCTs,(Bertrand 2006 843, Saïssy 2000 1523) in which passive ventilation through constant flow insufflation of oxygen with the aid of a modified endotracheal tube was compared to mechanical ventilation.
For the critical outcome of hospital discharge with favourable neurological outcome, we identified very low-quality evidence from 1 observational study (downgraded due to serious risk of bias and indirectness), which involved 1019 patients that showed no difference between passive (nonrebreather mask) and active (bag-mask) ventilation (adjusted RR, 1.03; 95% CI, 0.84 to 1.26 or 3 patients more/1000 survived with favourable neurological outcome [95%CI, 15 fewer patients/1000 to 25 more patients/1000 survived with intact neurologically recovery with the intervention]). (Bobrow 2009 656)
For the critical outcome of survival to ICU discharge, we found low-quality evidence from 2 RCTs, which involved 791 patients. These studies reported no significant difference in survival (RR, 0.96; 95% CI, 0.31 to 2.85 or 1 patients fewer/1000 survived with the intervention [95% CI, 14 fewer patients/1000 to 38 more patients/1000 survived with the intervention]).(Bertrand 2006 843, Saïssy 2000 1523)
For the important outcome of survival to hospital admission, we found low-quality evidence from 2 RCTs (Bertrand 2006 843, Saïssy 2000 1523) including 791 patients that found no benefit from passive ventilation (RR, 0.92; 95% CI, 0.64 to 1.24 or 14 patients fewer/1000 survived with the intervention [95% CI,61 fewer patients/1000 to 41 more patients/1000 survived with the intervention]).(Bertrand 2006 843)
For the important outcome of ROSC, we found low-quality evidence from 2 RCTs (Bertrand 2006 843, Saïssy 2000 1523) including 791 patients that found no benefit from passive ventilation (RR, 0.98; 95% CI, 0.85 to 1.12 or 4 patients fewer/1000 had ROSC with the intervention [95% CI, 31 fewer patients/1000 to 25 more patients/1000 had ROSC with the intervention]),(Bertrand 2006 843, Saïssy 2000 1523) and very low-quality evidence from 1 observational study and a very small pilot RCT (Bobrow 2009 656, Fuest 2021 85). The observational study reported similar rates of ROSC after implementation of a minimally interrupted cardiac resuscitation protocol (RR, 0.85; 95% CI, 0.77 to 1.00 or 45 patients fewer/1000 had ROSC with the intervention [95% CI, 69 fewer patients/1000 to 0 more patients/1000 had ROSC with the intervention]) (Bobrow 2009 656), while the pilot RCT reported no statistical difference in ROSC when chest compression-induced ventilation with continuous positive airway pressure in 9 patients was compared to standard volume-controlled ventilation in 11 patients (22% vs. 9%). (Fuest 2021 85)
We suggest against the routine use of passive ventilation techniques during conventional CPR (weak recommendation, very low-quality evidence).
Justification and Evidence to Decision Framework Highlights
This topic was prioritized by the BLS Task Force as the topic had not been reviewed since the 2015 Consensus on Science and Treatment recommendations.
Passive ventilation may represent an alternative to intermittent positive-pressure ventilation. In addition, this approach may shorten interruptions in chest compression for advance airway management and may overcome the potential detrimental effects of positive-pressure ventilation: rising in intrathoracic pressure; reduced venous return to the heart; reduced coronary perfusion pressure; increased pulmonary vascular resistance.
The RCTs compared intermittent positive-pressure ventilation via an endotracheal tube with continuous insufflation of oxygen through a modified endotracheal tube, i.e. Boussignac tube. The Boussignac tube used in these studies is known to generate a constant endotracheal pressure of approximately 10 cmH2O. In addition, the active compression decompression device, when available, was used to perform CPR. The above adjuncts may have played a role in the generation and in the magnitude of passive ventilation. The observational study presented critical problems related to indirectness. Indeed, different CPR protocols were compared, characterized not only by different ventilation strategies but also by different rhythm check timings, compression/ventilation ratios, and compression intervals between shocks. Overall, quality of evidence was rated as very low primarily due to a critical risk of bias due to confounding and indirectness.
We acknowledge that where EMS systems have adopted a bundle of care that includes minimally interrupted cardiac resuscitation with passive ventilation, it is reasonable to continue in the absence of compelling evidence to the contrary.
In making this recommendation, we place priority on consistency with our previous recommendations
in the absence of compelling evidence for improvement in any of our critical outcomes.
- No studies investigated passive ventilation in the lay rescuer setting.
- Which elements of the bundled care (compressions, ventilations, delayed defibrillation) are most important?
- What is the optimal method for ensuring a patent airway?
- Is there a critical volume of air movement required to maintain effectiveness?
- How effective is passive insufflation in children?
References listed alphabetically by first author last name in this citation format (Circulation)
- Bertrand C, Hemery F, Carli P, Goldstein P, Espesson C, Rüttimann M, Macher JM, Raffy B, Fuster P, Dolveck F, Rozenberg A, Lecarpentier E, Duvaldestin P, Saissy JM, Boussignac G, Brochard L; Boussignac Study Group. Constant flow insufflation of oxygen as the sole mode of ventilation during out-of-hospital cardiac arrest. Intensive Care Med. 2006 Jun;32(6):843-51.
- Saïssy JM, Boussignac G, Cheptel E, Rouvin B, Fontaine D, Bargues L, Levecque JP, Michel A, Brochard L. Efficacy of continuous insufflation of oxygen combined with active cardiac compression-decompression during out-of-hospital cardiorespiratory arrest. Anesthesiology. 2000 Jun;92(6):1523-30
- Bobrow BJ, Ewy GA, Clark L, Chikani V, Berg RA, Sanders AB, Vadeboncoeur TF, Hilwig RW, Kern KB. Passive oxygen insufflation is superior to bag-valve-mask ventilation for witnessed ventricular fibrillation out-of-hospital cardiac arrest. Ann Emerg Med. 2009 Nov;54(5):656-662
Fuest K, Dorfhuber F, Lorenz M, von Dincklage F, Mörgeli R, Kuhn KF, Jungwirth B, Kanz KG, Blobner M, Schaller SJ. Comparison of volume-controlled, pressure-controlled, and chest compression-induced ventilation during cardiopulmonary resuscitation with an automated mechanical chest compression device: A randomized clinical pilot study. Resuscitation. 2021 Sep;166:85-92