BLS 2401 Ventilation Parameters during Adult Cardiopulmonary Resuscitation: TF SR

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 declared an intellectual conflict of interest and this was acknowledged and managed by the Task Force Chairs and Conflict of Interest committees: Ian Drennan: Funding from ZOLL for study examining real-time ventilation feedback and a trial on ventilation. Nicholas Johnson: Funding from American Heart Association for study examining ventilation parameters during CPR. Guillaume Debaty: Published previous studies on ventilation during CPR. Betty Yang: Funding from American Heart Association for study examining ventilation parameters during CPR

CoSTR Citation

Johnson NJ, Debaty G, Yang BY, Moskowitz A, Drennan I, del Castillo J, Bray JE, Olasveengen T, Morrison LJ on behalf of the International Liaison Committee on Resuscitation Basic Life Support and Advanced Life Support Tasks Forces. Ventilation Parameters during Adult Cardiopulmonary Resuscitation Consensus on Science with Treatment Recommendations: International Liaison Committee on Resuscitation (ILCOR) Basic Life Support and Advanced Life Support Task Forces, 2026.  Available from: http://ilcor.org

Methodological Preamble and Link to Published Systematic Review

The continuous evidence evaluation process for the production of Consensus on Science with Treatment Recommendations (CoSTR) started with a systematic review ventilation practices during cardiopulmonary resuscitation conducted by Oslo University on October 8, 2024 and updated on November 10, 2025 with involvement of clinical content experts. Evidence for adult and pediatric literature was sought and considered by the Basic Life Support Task Force, Advanced Life Support Taks force, the Pediatric Task Force groups respectively. The Pediatric Task Force ultimately elected to conducted a separate systematic review and develop an independent CoSTR focused on children.

PICOST

PROSPERO Registration CRD420251070065

Consensus on Science

A total of 3021 titles and abstracts were screened. We found 13 eligible studies. In consultation with the Basic and Advanced Life Support Task Forces, the Pediatric Life Support Task Force elected to complete a separate review and CoSTR, so 2 pediatric studies were excluded. Of the remaining 11 adult studies, 3 were RCTs and 8 were observational studies. Studies were found assessing ventilation rate, tidal volume, and impedance-detected chest rise during CPR and overall were determined to provide very low certainty evidence due to serious risk of bias, inconsistency, indirectness, and imprecision. Data came primarily from observational studies and small RCTs involving heterogeneous patient populations, differing airway management strategies, and various measurement methods. No studies were identified comparing different PEEP levels or inspiratory times. We did not perform meta-analysis due to clinical and methodological heterogeneity in the included studies. Given the variation in study design, populations, and outcomes, we report study findings in a narrative fashion using the Synthesis without Meta-Analysis (SWiM) guidelines. (Cambell 2020)

• Ventilation Rate:
  • Survival to hospital discharge with favorable neurological outcome (Critical): We identified very low-certainty evidence (downgraded for risk of bias, inconsistency, indirectness) from 1 observational study and 1 post-hoc analysis of a randomized trial with 1010 patients receiving higher or lower ventilation rates.(Vissers 2019, Wang 2022) A retrospective study of 337 intubated adult patients with OHCA compared a ventilation rate of > 10 and ≤10 breaths per minute and found no difference in 1-year neurological outcome (aOR 0.59 [0.19– 1.87]). (Vissers 2019) A post-hoc subanalysis of the Pragmatic Airway in Resuscitation Trial (PART) including 1010 patients randomized to supraglottic airway or endotracheal intubation found that a longer duration of hypoventilation (< 6 breaths per minute) was not associated with neurologically intact survival (aOR 0.83 [0.66-1.05]) compared to the reference range of 6-12 breaths per minute. Duration of what as the authors defined as mild hyperventilation (>12-16 breaths per minute) was favorably associated with neurologically intact survival (aOR 1.36 [1.01-1.84]) compared with 6-12 breaths per minute.(Wang 2022)
  • Survival to hospital discharge or 30 days (Critical): We identified very low-certainty (downgraded for risk of bias, imprecision and indirectness) evidence from 2 observational studies and one post-hoc analysis of an RCT with 1005 patients, all of whom had advanced airways, comparing higher to lower ventilation rates during CPR. (Vissers 2019, Wang 2022) In the above retrospective study of 337 adults with OHCA comparing a ventilation rate of > 10 and ≤10 breaths per minute, the authors found no difference in survival to hospital discharge (aOR 0.91 [0.30– 2.7]). (Vissers 2019) In a post-hoc subanalysis of PART, a longer duration of hypoventilation (< 6 breaths per minute) was inversely associated survival to discharge (aOR 0.79 [0.72-0.87]). Duration of mild hyperventilation (>12-16 breaths per minute) was associated with higher survival to hospital discharge (aOR 1.23 [1.07-1.40]). Durations of moderate (>16-20 breaths per minute) and severe (>20 breaths per minute) were associated with survival to hospital discharge (aOR 1.22 [1.0-1.41]). (Wang 2022)
  • Return of Spontaneous Circulation (ROSC) (Important): We identified very low-certainty evidence (downgraded for bias and indirectness) from 1 RCT, 2 observational studies, and 1 post-hoc analysis of an RCT collectively enrolling 1279 patients with advanced airways comparing higher to lower ventilation rates.(Vissers 2019, Wang 2022, Prause 2023, Jaffe 2025) We identified one small RCT that included 46 adults with OHCA. Ventilation was conducted via a mechanical ventilator. The trial showed no difference between a ventilation rate of 10 and 20 breaths per minute in ROSC (48 vs 52%, p=0.44). The above retrospective study of 337 patients with OHCA compared a ventilation rate of > 10 and ≤10 breaths per minute and found no difference in ROSC (aOR 0.91 [0.49-1.71]).(Vissers 2019) A secondary analysis of a prospective multicenter cohort of adults with IHCA and advanced airways in situ demonstrated that patients with mean ventilation rates >12 breaths/min achieved ROSC in 45% of cases compared to 24% for rates within the AHA guideline range (6–12 breaths/min; p=0.009), with 86% of ROSC patients ventilated above 12 breaths/min.(Jaffe 2025) A two breaths/min increase in mean ventilation rate was associated with a 15% increase in the odds of ROSC (OR = 1.15, 95% CI 1.05–1.26, p<0.001 univariate; OR = 1.15, 95% CI 1.04–1.28, p=0.006 multivariate), though cubic spline modeling indicated a turning point around 26.7 breaths/min where ROSC probability began to decline. The PART subanalysis (detailed above) found that a longer duration of hypoventilation (defined as < 6 breaths per minute) was inversely associated with ROSC (adjusted OR 0.96 [0.94-0.99]).(Wang 2022) Duration of mild hyperventilation (>12-16 breaths per minute) was favorably associated with ROSC (aOR 1.09 [1.04-1.15]).
  • pH (Important): We identified 1 small RCT that included 46 adults with OHCA treated with tracheal intubation and mechanical ventilation. This study found no difference comparing a ventilation rate of 10 and 20 breaths per minute in pH (6.89 vs 6.83, p=0.8) approximately 20 minutes from initiation of ACLS.(Prause 2023)
  • Table: BLS 2401 GRADE table ventilation rate

• Tidal volume:
  • Survival to hospital discharge with favorable neurological outcome (Critical): We identified very low-certainty evidence (downgraded for risk of bias, inconsistency, indirectness) from 2 observational studies with 2006 adults patients comparing higher to lower tidal volumes.(Snyder 2023, Yang 2022) The first compared ventilation with a small ventilation bag (expected delivered tidal volume 450 ml) and a large ventilation bag (expected delivered volume 750 ml) in 1994 patients with OHCA and advanced airways and found no difference in neurologically intact survival.(Snyder 2023) The second, which measured inspiratory tidal volumes measured using a blinded spirometry-based device in intubated patients, compared outcomes in 12 patients ventilated with a small bag (median tidal volumes 383 [329, 450] ml) vs 20 patients with a large bag (median tidal volume 422 [328, 541] ml) and found no difference in discharge to home location (17 vs 10%, p=0.71), a potential surrogate for neurological status at hospital discharge, but did not assess neurological outcome directly.(Yang 2022)
  • Survival to hospital discharge or 30 days (Critical): We identified very low-certainty evidence (downgraded for risk of bias, imprecision and indirectness) from 2 non-RCTs with 2006 patients with advanced airways comparing higher and lower tidal volumes.(Snyder 2023, Yang 2022) The first, as detailed above, compared ventilation bag size in 1994 patients with OHCA and reported no statistically significant difference in survival to hospital discharge (aOR 0.79 [0.57–1.09]) among patients ventilated with a small ventilation bag (expected delivered tidal volume 450 ml) compared with a large ventilation bag (expected delivered volume 750 ml).(Snyder 2023) The second study, which included tidal volumes measured using a blinded spirometry-based device, compared outcomes in 12 patients ventilated with a small bag to 20 patients with a large bag, found no statistical difference in survival to discharge (33 vs 10%, p=0.9), though the point estimate favored the small bag group.
  • ROSC (Important): We identified very low-certainty evidence (downgraded for indirectness and bias) from 2 RCTs and 2 observational studies enrolling 2103 patients comparing higher with lower tidal volumes among patients with advanced airways receiving CPR.(Snyder 2023, Yang 2022, Langhelle 2000, Shin 2024) Together, the two RCTs included 77 adult patients with OHCA. The first, a pilot randomized trial, compared ventilation with a volume of 500 ml to 1000 ml in 17 patients with OHCA. ROSC was achieved in 3/9 (30%) of patients in the 500 ml arm compared with 0/8 in the 1000 ml arm.(Langhette 2000) The second RCT compared two approaches to ventilation, bag (BV) and mechanical (MV), in 60 intubated patients with OHCA who were transported to the ED with ongoing CPR.(Shin 2024) Different median tidal volumes were delivered via each approach: BV 267 [IQR 137-382] ml vs MV 507 [IQR 403-606] ml. The trial found no difference in ROSC (BV 43 vs MV 57%, p=0.3). No other clinical outcomes were reported. In a retrospective study of 1994 patients with OHCA (detailed above) comparing ventilation with a small ventilation bag and a large ventilation bag, patients ventilated with the smaller bag had lower odds of ROSC (0.74 [0.61–0.91]).(Snyder 2023) In a study of 32 patients with tidal volumes measured using a blinded spirometry-based device, there was no statistical difference in ROSC comparing the large and small ventilation bag groups (67 vs 45%,p=0.98).
  • pH (Important): We identified 2 randomized trials and 1 observational study that reported pH among patients ventilated with different tidal volumes. All studies included patients with advanced airways.(Snyder 2023, Langhelle 2000, Shin 2024) In a pilot randomized trial, comparing ventilation with a volume of 500 ml to 1000 ml in 17 patients with OHCA, Median pH was lower in the 500 ml compared with the 1000 ml arm (7.01±0.1 vs. 7.2±0.2, p=0.03).(Langhelle 2000) Another randomized trial compared two approaches to ventilation, bag (BV) and mechanical (MV), in 60 patients with OHCA who were transported to the ED with ongoing CPR. The study compared median tidal volumes delivered via each approach (BV 267 ml [IQR 137-382] vs MV 507 ml [IQR 403-606]) and found no difference in pH (BV 6.9 [6.7-7.07] vs MV 6.9 (6.8-6.98)).(Shin 2024) In an observational study of 1994 patients with OHCA ventilated with a smaller bag compared with a larger bag, there was no difference in pH on hospital arrival (7.09 vs. 7.06).(Snyder 2023)
  • Table: BLS 2401 GRADE table tidal volume

• Impedance-detected ventilations:
  • Survival to hospital discharge with favorable neurological outcome (Critical): We identified very low-certainty evidence (downgraded for bias and imprecision) from 2 post-hoc analyses of RCTs 2528 patients comparing impedance-detected lung inflation during ventilation when performing 30:2 CPR without an advanced airway.(Chang 2019, Idris 2023) Both studies defined lung inflation as transthoracic impedance (TTI) deflections greater than 2mm—corresponding to tidal volumes over 250 mL in a separate cohort of healthy volunteers. Studies compared whether impedance-detected lung inflation in ≥50% of chest compression pauses were associated with clinical outcomes compared with impedance-detected lung inflation in <50% of chest compression pauses. The first study, which included 560 adult patients with OHCA, found higher odds of survival with favorable neurological outcome in the group that received at least one ventilation in ≥50% of chest compression pauses (aOR 4.14 [1.14-15.1]).(Chang 2019) The second study included 1,976 patients from the 30:2 arm of the Resuscitation Outcomes Consortium’s Continuous Chest Compressions trial found that patients with ventilations detected by TTI in ≥50% of pauses had higher odds of survival with favorable neurological outcomes (aRR 2.8 [1.8-4.3]).(Idris 2023)
  • Survival to hospital discharge or 30 days (Critical): We identified very low-certainty evidence (downgraded for risk of bias, indirectness) from 2 post-hoc analyses of an RCT enrolling 2528 patients comparing ventilation with impedance-detected lung inflation in ≥50% of chest compression pauses compared with ventilation waveforms in < 50% of chest compression pauses during 30:2 CPR without an advanced airway.(Chang 2019, Idris 2023) In the first study of which included 560 adult OHCA patients, those with TTI-detected lung inflation in ≥50% of pauses achieved higher survival to hospital discharge (aOR 2.13 [0.83-5.47]).(Chang 2019) The second of 1,976 patients from the 30:2 arm of the Resuscitation Outcomes Consortium Continuous Chest Compressions trial found that patients with lung inflation detected by TTI in ≥50% of pauses had higher survival to hospital discharge (aRR 2.2 [1.6-3]) compared to those with lung inflation detected in <50% of pauses.(Idris 2023)
  • ROSC (Important): We identified very low-certainty evidence (downgraded for bias, indirectness) from 2 post-hoc analyses of an RCT enrolling 2528 patients undergoing 30:2 CPR without advanced airways. The studies compared ventilation with impedance-detected lung inflation in >=50% of chest compression pauses compared with ventilation waveforms in < 50% of chest compression pauses. The first study of 560 adult OHCA patients reported higher odds of ROSC (aOR 2.84 [1.47-5.48]) among patients with impedance-detected lung inflation >=50% of chest compression pauses.(Chang 2019) The second study of 1,976 patients similarly found that adult patients with OHCA with lung inflation detected by TTI in ≥50% of pauses had higher risk of ROSC (aRR 1.3 [1.2-1.6]).(Idris 2023)
  • Table: BLS 2401 GRADE table impedance

Treatment Recommendations

• We suggest delivering 2 ventilations for every 30 compressions or 10 ventilations per minute (1 every 6 seconds) for continuous compressions in adults with cardiac arrest with or without an advanced airway (Weak recommendation, very low certainty of evidence).

• When providing manual ventilation, it is reasonable to deliver enough volume to produce visible chest rise (Good Practice Statement).

• When tidal volume can be measured, we suggest delivering a tidal volume of 400-600 ml (or 6-10 milliliters per kilogram of ideal/predicted body weight) in adults with cardiac arrest (Weak recommendation, very low certainty of evidence).

• It is reasonable to ensure effective ventilation and avoid both hyperventilation and hypoventilation (Good Practice Statement).

Justification and Evidence to Decision Framework Highlights

• This topic was prioritized by the BLS, ALS, and PLS Task Forces as a nodal review based on multiple recent observational studies demonstrating association between ventilation parameters and outcomes as well as several small randomized trials.(Chang 2019, Idris 2023)

• The 2010 Treatment Recommendation was based only on observational studies and extrapolation from animal studies and healthy volunteers.

• Ventilation during cardiac arrest encompasses multiple components including rate, volume, and monitoring, as well as airway devices, feedback, and integration with chest compressions. Most patients in the included studies received ventilations via advanced airway devices (supraglottic devices or tracheal tubes). Separate CoSTRs address airway devices, feedback, and integration with chest compressions.

• While the search strategy initially included children, the limited number of studies in this population combined with their unique respiratory physiology during cardiac arrest prompted the Pediatric Life Support Task Force to undertake an independent review and develop pediatric-specific treatment recommendations, so two pediatric studies were excluded from this review. All treatment recommendations pertain to adult patients only.

• Given the significant clinical and methodological heterogeneity among studies, including populations, interventions, and outcomes, the TFs agreed that meta-analysis is not possible.

• The use of experimental/animal or manikin studies was discussed. It was determined that there is likely sufficient evidence in humans to not include these studies.

• In considering the importance of this topic we noted that existing evidence is conflicting and challenging to interpret, with older studies documenting harm due to hyperventilation, and more recent studies noting the opposite, with hypoventilation being common and associated with poor outcomes, especially in the absence of an advanced airway.(Chang 2019, Idris 2023, Aufderheide 2004, Aufderheide 2004) Conflicting findings may arise from heterogeneity in population characteristics, methods of ventilation delivery (manual vs. mechanical), and study designs.

• The TFs also noted absence of large, multicenter randomized trials, so elected to include both randomized trials and observational studies. Existing RCTs are small, single-center, and underpowered to draw definitive conclusions on ventilation practices during cardiac arrest. Larger multicenter RCTs are urgently needed to confirm findings, especially for intervention parameters like ventilation rate, tidal volume, inspiratory time, and airway pressures/PEEP.(Prause 2023, Shin 2024)

• The TFs noted that tidal volume delivery is not often known or measured in the prehospital setting, though there are several relatively new devices capable of measuring inspiratory (and in some cases expiratory) volume and ventilation rate. A recent ILCOR review concluded that, there is insufficient evidence that ventilation feedback devices improve the quality of ventilation or clinical outcomes.(Debaty 2025) Whether using these devices during training translates to improved ventilation effectiveness in real-life scenarios is unknown.

• The ventilation rate treatment recommendations align with past guidance and reviewed evidence suggesting potential harm from hypoventilation, but do not support strong recommendations for higher rates. The Task Forces considered setting an upper limit for ventilation rate based on older data indicating harm from hyperventilation. However, they noted a lack of recent evidence confirming these findings. Ultimately, the Task Forces voted not to include an upper limit.

• Physiologic principles and indirect evidence support targeting tidal volumes sufficient to maintain oxygenation and CO₂ clearance, while avoiding excessive intrathoracic pressure. Observational studies suggest that very low tidal volumes may be associated with harm. Randomized controlled trials and observational data show no survival benefit from using larger volumes. Pulmonary-specific outcomes, such as barotrauma and ARDS, were not reported in the reviewed studies; however, evidence from other disease states suggests that excessive volumes may be detrimental.

• The Task Forces considered whether absolute tidal volumes (measured in milliliters) or tidal volumes based on predicted (or ideal or healthy) body weight—commonly used in hospital practice—would be more appropriate. Ultimately, they chose to include both approaches to accommodate diverse clinical settings and providers, but acknowledge that different terms are used in different contexts. Councils may need to adapt the terminology to local terminology and practice.

• The Task Force also noted that chest rise, although frequently used to assess ventilation adequacy in prehospital care, may be difficult to evaluate during continuous CPR. Older studies have shown that chest rise can occur at tidal volumes as low as 180 ml, which may not indicate adequate ventilation.(Baskett 1996)

• Due to limitations in the included studies and small sample sizes, we were not able to perform subgroup analyses according to pre-specified characteristics (e.g., age, gender, arrest etiology).

EtD: BLS 2401 Ventilation Parameters during Adult Cardiopulmonary Resuscitation EtD

Knowledge Gaps

• There are no RCTs adequately powered to detect differences in neurologically-intact survival.

• Future research should focus on identifying precise thresholds for “higher” and “lower” ventilation rates across different patient populations and settings (e.g., in-hospital vs. out-of-hospital cardiac arrests).

• There is insufficient evidence to determine the ideal tidal volume for ventilation during cardiac arrest. While animal and historical studies suggested smaller tidal volumes to avoid barotrauma and intrathoracic pressure elevation, recent findings are inconsistent (e.g., Snyder et al., 2023 showing mixed results).

• There is virtually no evidence in special populations such as pregnant patients.

• There is limited evidence on whether ventilation rate, tidal volume, or adequacy strategies differ in patients with advanced airways compared to those managed with basic airway techniques (e.g., bag-mask ventilation or 30:2 CPR without airway insertion). Especially in non-intubated patients, it is important to measure expiratory volume because this will take into account mask or supraglottic airway leakage

• Some physiologic data suggests that intrathoracic airway closure may affect ventilation during CPR, but the impact on outcomes is not clear.

• Little mechanistic data exist. Blood gases, when reported, were often obtained after ROSC.

• Evidence is limited regarding whether ventilation practices and their associated outcomes differ based on etiology, initial arrest rhythm, or other patient-specific factors.

References