Ventilation caused by external chest compression is unable to sustain effective gas exchange during CPR: a comparison with mechanical ventilation

doi:10.1016/0300-9572(94)90087-6

Resuscitation

Volume 28, Issue 2, October 1994, Pages 143-150

https://doi.org/10.1016/0300-9572(94)90087-6 Get rights and content

Abstract

Objective: To compare the tidal volume, minute ventilation, and gas exchange caused by mechanical chest compression with and without mechanical ventilatory support during cardiopulmonary resuscitation (CPR) in a laboratory model of cardiac arrest. Design: A laboratory swine model of CPR was used. Eight animals with and eight animals without mechanical ventilation received chest compression (100/min) for 10 min. Coronary perfusion pressure, tidal volume, and minute ventilation were recorded continuously. Interventions: Ventricular fibrillation for 6 min without CPR, then mechanical chest compression for 10 min. Results: During the first minute of chest compression, mean (± S.D.) minute ventilation was 11.2 ± 5.91 l/min in the mechanically ventilated group and 4.5 ± 2.8 l/min in the group without mechanical ventilation (P = 0.01). Minute ventilation gradually declined to 5.8 ± 1.4 1/min and 1.7 ± 1.6 1/min, respectively, during the last minute of chest compression (P < 0.0001). After 10 min of chest compression, mean arterial pH was significantly more acidemic in the group without mechanical ventilation (7.16 ± 0.13 compared with 7.30 ± 0.07 units) and Pco₂ was higher (62 ± 19 compared with 35 ± 9 mmHg). Mixed venous Pco₂ was also higher (76 ± 15 compared with 61 ± 8 mmHg). Conclusion: Standard chest compression alone produced measurable tidal volume and minute ventilation. However, after 10 min of chest compression following 6 min of untreated ventricular fibrillation, it failed to sustain pulmonary gas exchange as indicated by significantly greater arterial and mixed venous hypercarbic acidosis when compared with a group receiving mechanical ventilation.

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A retrospective comparison of mechanical cardio-pulmonary ventilation and manual bag valve ventilation in non-traumatic out-of-hospital cardiac arrests: A study from the Belgian cardiac arrest registry
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The optimal ventilation modalities to manage out-of-hospital cardiac arrest (OHCA) remain debated. A specific pressure mode called cardio-pulmonary ventilation (CPV) may be used instead of manual bag ventilation (MBV). We sought to analyse the association between mechanical CPV and return of spontaneous circulation (ROSC) in non-traumatic OHCA.
MBV and CPV were retrospectively identified in patients with non-traumatic OHCA from the Belgian Cardiac Arrest Registry. We used a two-level mixed-effects multivariable logistic regression analysis to determine the association between the ventilation modalities and outcomes. The primary and secondary study criteria were ROSC and survival with a Cerebral Performance Category (CPC) score of 1 or 2 at 30 days. Age, sex, initial rhythm, no-flow duration, low-flow duration, OHCA location, use of a mechanical chest compression device and Rankin status before arrest were used as covariables.
Between January 2017 and December 2021, 2566 patients with OHCA who fulfilled the inclusion criteria were included. 298 (11.6%) patients were mechanically ventilated with CPV whereas 2268 were manually ventilated. The use of CPV was associated with greater probability of ROSC both in the unadjusted (odds ratio: 1.28, 95% confidence interval [CI]: 1.01–1.63; p = 0.043) and adjusted analyses (adjusted odds ratio [aOR]: 2.16, 95%CI 1.37–3.41; p = 0.001) but not with a lower CPC score (aOR: 1.44, 95%CI 0.72–2.89; p = 0.31).
Compared with MBV, CPV was associated with an increased risk of ROSC but not with improved an CPC score in patients with OHCA. Prospective randomised trials are needed to challenge these results.
Chest compressions during ventilation in out-of-hospital cardiopulmonary resuscitation cause fragmentation of the airflow
2021, American Journal of Emergency Medicine
When a patient suffers an out-of-hospital cardiac arrest, ventilation and chest compressions are often given simultaneously during cardiopulmonary resuscitation. These simultaneous chest compressions may cause a fragmentation of the airflow, which may lead to an ineffective ventilation. This study focusses on the occurrence and quantification of this fragmentation and its effect on ventilation.
This study is a single-center observational study, held at Ghent University Hospital. A custom-built bidirectional flow sensor was used to quantify the volumes of ventilation. Adult cardiac arrest patients who were prehospitally intubated and resuscitated by the medical emergency team were eligible for inclusion. Data of the patients who were ventilated and received simultaneous chest compressions, was used to calculate the volumes of ventilation and the amount and volumes of fragmentation. All data in this study is reported as mean (standard deviation; range).
Data of 10 patients (7 male) with a mean age of 71 years (14;51–87) was used in this study. The mean ventilation frequency was 12/min (2;9–16), the mean minute volume and tidal volume were respectively 6.21 L (1.51;3.79–8.15) and 514 mL (99;422–682). Fragmentation of the airflow was observed in all patients, with an average of 3 (1;2–5) fragments per inspiration and a mean volume of 214 mL (65;112–341) per fragment.
Chest compressions during ventilation caused fragmentation of the airflow in all patients. There was wide variation in the number and volume of the fragments between patients. The importance of quantification of airflow volumes and the effect fragmentation of the airflow on the efficacy of ventilation can be essential in improving cardiopulmonary resuscitation techniques and therefore needs further investigation.
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
2021, Resuscitation
Automated mechanical chest compression devices (AMCCDs) can help performing high-quality cardiopulmonary resuscitation (CPR). Guidelines for CPR are lacking information about the optimal ventilation mode during CPR using AMCCDs. Aim of this pilot study was to compare three common ventilation modes during CPR using AMCCD.
In this randomized controlled trial, we included patients with an out-of-hospital cardiac arrest arriving at the resuscitation room receiving chest compressions via AMCCD with an expected continuation of at least 15 min. Patients were randomly assigned to three groups: biphasic positive airway pressure with assisted spontaneous ventilation (BIPAP) with assisted spontaneous breathing, continuous positive airway pressure (CPAP) and volume-controlled ventilation (VCV). Outcomes were tidal volume, respiratory minute volume, and end-tidal CO₂ during the study period. Groups were compared using generalized linear models. Data is given as median and interquartile ranges.
Of 53 screened patients, 30 were randomized. The tidal volume was significantly (p < 0.05) lower in patients of the CPAP group (68 [64–83] ml) compared with those of the BIPAP (349 [137–500] ml), while the respiratory minute volume differed between the CPAP group (6.2 [5.3–8.1] l/min) and both the BIPAP (7.1 [6.7–10.2] l/min) and VCV group (7.2 [3.7–8.4] l/min).
All ventilation modes achieved an adequate respiratory minute volume during CPR with an AMCCD. However, BIPAP seems to be superior due to the higher tidal volume. Therefore, we recommend starting mechanical ventilation when using AMCCD with BIPAP ventilation to avoid risks related to dead space ventilation.
The impact of introducing real time feedback on ventilation rate and tidal volume by ambulance clinicians in the North East in cardiac arrest simulations
2021, Resuscitation Plus
Research suggests rescuers deliver ventilations outside of recommendations during out of hospital cardiac arrest (OHCA), which can be deleterious to survival. We aimed to determine if ambulance clinician compliance with ventilation recommendations could be improved using the Zoll Accuvent real time ventilation feedback device (VFD).
Participants simulated a two-minute cardiac arrest scenario using a mannequin and defibrillator without ventilation feedback. Eligible for inclusion were all clinicians aged ≥18 years who perform cardiopulmonary resuscitation (CPR) as part of their role, who had completed an internal advanced life support (ALS) refresher. Following familiarisation of a few minutes with the VFD, participants repeated the two-minute scenario with ventilation feedback. Ventilation rate and volume and CPR quality were recorded. Primary outcome was % difference in ventilation compliance with and without feedback. Secondary outcomes were differences between paramedic and non-paramedic clinicians and compliance with chest compression guidelines.
One hundred and six participants completed the study. Median ventilation rate without feedback was 10 (IQR 8–14, range 4–30) compared to 9 (IQR 9–9, range 6–17) with feedback; median tidal volume without feedback was 630 mls (IQR 518–725, range 201–1114) compared to 546 mls (IQR 531–560, range 490–750) with feedback. Proportion of clinicians ≥50% compliant with European Resuscitation Council ventilation recommendations were significantly greater with ventilation feedback compared to without, 91% vs. 9%, (McNemars test p = <0.0001). Paramedics out performed non-paramedic clinicians with and without feedback and compression quality was not compromised by using the VFD.
Ambulance clinician baseline ventilation quality was frequently outside of recommendations, but a VFD can ensure treatment is within evidence-based recommendations. Further research is required to validate the use of the VFD in true clinical practice and to evaluate the relationship between improved ventilation quality during OHCA and patient outcomes.
Do manual chest compressions provide substantial ventilation during prehospital cardiopulmonary resuscitation?
2021, American Journal of Emergency Medicine
Citation Excerpt :
This mechanism was first reported in 1961 by Peter Safar, who observed that chest compressions generated an average tidal volume of 156 mL in curarised, intubated healthy subjects [8]. In animal models of cardiac arrest, manual chest compressions have been shown to generate limited alveolar ventilation [9-11]. In humans, measurements of ventilation generated by manual and mechanical chest compressions have only been performed after arrival of OHCA patients in the emergency department (ED).
Chest compressions have been suggested to provide passive ventilation during cardiopulmonary resuscitation. Measurements of this passive ventilatory mechanism have only been performed upon arrival of out-of-hospital cardiac arrest patients in the emergency department. Lung and thoracic characteristics rapidly change following cardiac arrest, possibly limiting the effectiveness of this mechanism after prolonged resuscitation efforts. Goal of this study was to quantify passive inspiratory tidal volumes generated by manual chest compression during prehospital cardiopulmonary resuscitation.
A flowsensor was used during adult out-of-hospital cardiac arrest cases attended by a prehospital medical team. Adult, endotracheally intubated, non-traumatic cardiac arrest patients were eligible for inclusion. Immediately following intubation, the sensor was connected to the endotracheal tube. The passive inspiratory tidal volumes generated by the first thirty manual chest compressions performed following intubation (without simultaneous manual ventilation) were calculated.
10 patients (5 female) were included, median age was 64 years (IQR 56, 77 years). The median compression frequency was 111 compression per minute (IQR 107, 116 compressions per minute). The median compression depth was 5.6 cm (IQR 5.4 cm, 6.1 cm). The median inspiratory tidal volume generated by manual chest compressions was 20 mL (IQR 13, 28 mL).
Using a flowsensor, passive inspiratory tidal volumes generated by manual chest compressions during prehospital cardiopulmonary resuscitation, were quantified. Chest compressions alone appear unable to provide adequate alveolar ventilation during prehospital treatment of cardiac arrest.
Association of ventilation with outcomes from out-of-hospital cardiac arrest
2019, Resuscitation
To determine the association between bioimpedence-detected ventilation and out-of-hospital cardiac arrest (OHCA) outcomes.
This is a retrospective, observational study of 560 OHCA patients from the Dallas-Fort Worth site enrolled in the Resuscitation Outcomes Consortium Trial of Continuous or Interrupted Chest Compressions During CPR from 4/2012 to 7/2015. We measured bioimpedance ventilation (lung inflation) waveforms in the pause between chest compression segments (Physio-Control LIFEPAK 12 and 15, Redmond, WA) recorded through defibrillation pads. We included cases ≥18 years with presumed cardiac cause of arrest assigned to interrupted 30:2 chest compressions with bag-valve-mask ventilation and ≥2 min of recorded cardiopulmonary resuscitation. We compared outcomes in two a priori pre-specified groups: patients with ventilation waveforms in <50% of pauses (Group 1) versus those with waveforms in ≥50% of pauses (Group 2).
Mean duration of 30:2 CPR was 13 ± 7 min with a total of 7762 pauses in chest compressions. Group 1 (N = 424) had a median 11 pauses and 3 ventilations per patient vs. Group 2 (N = 136) with a median 12 pauses and 8 ventilations per patient, which was associated with improved return of spontaneous circulation (ROSC) at any time (35% vs. 23%, p < 0.005), prehospital ROSC (19.8% vs. 8.7%, p < 0.0009), emergency department ROSC (33% vs. 21%, p < 0.005), and survival to hospital discharge (10.3% vs. 4.0%, p = 0.008).
This novel study shows that ventilation with lung inflation occurs infrequently during 30:2 CPR. Ventilation in ≥50% of pauses was associated with significantly improved rates of ROSC and survival.

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Experimental studyVentilation caused by external chest compression is unable to sustain effective gas exchange during CPR: a comparison with mechanical ventilation

Abstract

Artificial respiration: comparison of manual maneuvers

Anesth Analg

Artificial respiration: a new method and a comparative study of different methods in adults

J Am Med Assoc

Critical survey of manual artificial respiration

J Am Med Assoc

Air-flow patterns and pulmonary ventilation during manual artificial respiration on apneic normal adults II

J Appl Physiol

Mouth-to-mouth versus manual artificial respiration for children and adults

J Am Med Assoc

Comparison of methods for performing manual artificial respiration on apneic patients

J Appl Physiol

Experimental study
Ventilation caused by external chest compression is unable to sustain effective gas exchange during CPR: a comparison with mechanical ventilation