Ventilation during cardiopulmonary resuscitation with mechanical chest compressions: How often are two insufflations being given during the 3-second ventilation pauses?

BACKGROUND: Mechanical chest compression devices in 30:2 mode provide 3-second pauses to allow for two insufflations. We aimed to determine how often two insufflations are provided in these ventilation pauses, in order to assess if prehospital providers are able to ventilate out-of-hospital cardiac arrest (OHCA) patients successfully during mechanical chest compressions. METHODS: Data from OHCA cases of the regional ambulance service of Utrecht, The Netherlands, were prospectively collected in the UTrecht studygroup for OPtimal registry of cardIAc arrest database (UTOPIA). Compression pauses and insufflations were visualized on thoracic impedance and waveform capnography signals recorded by manual defibrillators. Ventilation pauses were analyzed for number of insufflations, duration of the subintervals of the ventilation cycles, and ratio of successfully providing two insufflations over the course of the resuscitation. Generalized linear mixed effects models were used to accurately estimate proportions and means. RESULTS: In 250 cases, 8473 ventilation pauses were identified, of which 4305 (51%) included two insufflations. When corrected for non-independence of the data across repeated measures within the same subjects with a mixed effects analysis, two insufflations were successfully provided in 45% of ventilation pauses (95% CI: 40-50%). In 19% (95% CI: 16-22%) none were given. CONCLUSION: Providing two insufflations during pauses in mechanical chest compressions is mostly unsuccessful. We recommend developing strategies to improve giving insufflations when using mechanical chest compression devices. Increasing the pause duration might help to improve insufflation success.

Oxygenation and ventilation during prolonged experimental cardiopulmonary resuscitation with either continuous or 30:2 compression-to-ventilation ratios together with 10 cmH20 positive end-expiratory pressure.

BACKGROUND: In refractory out-of-hospital cardiac arrest, the patient is commonly transported to hospital with mechanical continuous chest compressions (CCC). Limited data are available on the optimal ventilation strategy. Accordingly, we compared arterial oxygenation and haemodynamics during manual asynchronous continuous ventilation and compressions with a 30:2 compression-to-ventilation ratio together with the use of 10 cmH2O positive end-expiratory pressure (PEEP). METHODS: Intubated and anaesthetized landrace pigs with electrically induced ventricular fibrillation were left untreated for 5 min (n = 31, weight ca. 55 kg), after which they were randomized to either the CCC group or the 30:2 group with the the LUCAS® 2 piston device and bag-valve ventilation with 100% oxygen targeting a tidal volume of 8 ml/kg with a PEEP of 10 cmH2O for 35 min. Arterial blood samples were analysed every 5 min, vital signs, near-infrared spectroscopy and electrical impedance tomography (EIT) were measured continuously, and post-mortem CT scans of the lungs were obtained. RESULTS: The arterial blood values (median + interquartile range) at the 30-min time point were as follows: PaO2: 180 (86-302) mmHg for the 30:2 group; 70 (49-358) mmHg for the CCC group; PaCO2: 41 (29-53) mmHg for the 30:2 group; 44 (21-67) mmHg for the CCC group; and lactate: 12.8 (10.4-15.5) mmol/l for the 30:2 group; 14.7 (11.8-16.1) mmol/l for the CCC group. The differences were not statistically significant. In linear mixed models, there were no significant differences between the groups. The mean arterial pressures from the femoral artery, end-tidal CO2, distributions of ventilation from EIT and mean aeration of lung tissue in post-mortem CTs were similar between the groups. Eight pneumothoraces occurred in the CCC group and 2 in the 30:2 group, a statistically significant difference (p = 0.04). CONCLUSIONS: The 30:2 and CCC protocols with a PEEP of 10 cmH2O resulted in similar gas exchange and vital sign outcomes in an experimental model of prolonged cardiac arrest with mechanical compressions, but the CCC protocol resulted in more post-mortem pneumothoraces.

Impact of teaching on use of mechanical chest compression devices: a simulation-based trial.

BACKGROUND: The use of mechanical chest compression devices on patients in cardiac arrest has not shown benefits in previous trials. This is surprising, given that these devices can deliver consistently high-quality chest compressions without interruption. It is possible that this discrepancy is due to the no-flow time (NFT) during the application of the device. In this study, we aimed to demonstrate a reduction in no-flow time during cardiopulmonary resuscitation (CPR) with mechanical chest compression devices following 10 min of structured training in novices. METHODS: 270 medical students were recruited for the study. The participants were divided as a convenience sample into two groups. Both groups were instructed in how to use the device according to the manufacturer's specifications. The control group trained in teams of three, according to their own needs, to familiarise themselves with the device. The intervention group received 10 min of structured team training, also in teams of three. The participants then had to go through a CPR scenario in an ad-hoc team of three, in order to evaluate the training effect. RESULTS: The median NFT was 26.0 s (IQR: 20.0-30.0) in the intervention group and 37.0 s (IQR: 29.0-42.0) in the control group (p < 0.001). In a follow-up examination of the intervention group four months after the training, the NFT was 34.5 s (IQR: 24.0-45.8). This represented a significant deterioration (p = 0.015) and was at the same level as the control group immediately after training (p = 0.650). The position of the compression stamp did not differ significantly between the groups. Groups that lifted the manikin to position the backboard achieved an NFT of 35.0 s (IQR: 27.5-42.0), compared to 41.0 s (IQR: 36.5-50.5) for the groups that turned the manikin to the side (p = 0.074). CONCLUSIONS: This simulation-based study demonstrated that structured training can significantly reduce the no-flow time when using mechanical resuscitation devices, even in ad-hoc teams. However, this benefit seems to be short-lived: after four months no effect could be detected.

Use of Mechanical Chest Compression for Resuscitation in Out-Of-Hospital Cardiac Arrest-Device Matters: A Propensity-Score-Based Match Analysis.

BACKGROUND: Devices for mechanical cardiopulmonary resuscitation (CPR) are recommended when high quality CPR cannot be provided. Different devices are available, but the literature is poor in direct comparison studies. Our aim was to assess whether the type of mechanical chest compressor could affect the probability of return of spontaneous circulation (ROSC) and 30-day survival in Out-of-Hospital Cardiac Arrest (OHCA) patients as compared to manual standard CPR. METHODS: We considered all OHCAs that occurred from 1 January 2015 to 31 December 2022 in seven provinces of the Lombardy region equipped with three different types of mechanical compressor: Autopulse®(ZOLL Medical, MA), LUCAS® (Stryker, MI), and Easy Pulse® (Schiller, Switzerland). RESULTS: Two groups, 2146 patients each (manual and mechanical CPR), were identified by propensity-score-based random matching. The rates of ROSC (15% vs. 23%, p < 0.001) and 30-day survival (6% vs. 14%, p < 0.001) were lower in the mechanical CPR group. After correction for confounders, Autopulse® [OR 2.1, 95%CI (1.6-2.8), p < 0.001] and LUCAS® [OR 2.5, 95%CI (1.7-3.6), p < 0.001] significantly increased the probability of ROSC, and Autopulse® significantly increased the probability of 30-day survival compared to manual CPR [HR 0.9, 95%CI (0.8-0.9), p = 0.005]. CONCLUSION: Mechanical chest compressors could increase the rate of ROSC, especially in case of prolonged resuscitation. The devices were dissimilar, and their different performances could significantly influence patient outcomes. The load-distributing-band device was the only mechanical chest able to favorably affect 30-day survival.

An Esophagopleural Fistula Related to Cardiopulmonary Resuscitation.

We describe a previously unreported and potentially fatal complication of esophageal perforation following cardiopulmonary resuscitation in a 74-year-old man with cardiac arrest subsequent to ventricular tachycardia caused by ischemic heart disease. We discuss the importance of searching for severe traumatic complications. This description emphasizes presenting complaints, early recognition, and management strategies of such cases (Level of Difficulty: Intermediate).

Injuries associated with mechanical chest compressions and active decompressions after out-of-hospital cardiac arrest: A subgroup analysis of non-survivors from a randomized study.

Background: Both skeletal and visceral injuries are reported after cardiopulmonary resuscitation (CPR). This subgroup analysis of a randomized clinical study describes/compares autopsy documented injury patterns caused by two mechanical, piston-based chest compression devices: standard LUCAS® 2 (control) and LUCAS® 2 with active decompression (AD, intervention) in non-survivors with out-of-hospital cardiac arrest (CA). Method: We compared injuries documented by autopsies (medical/forensic) after control and intervention CPR based on written relatives consent to use patients' data. The pathologists were blinded for the device used. The cause of CA and injuries reported were based on a prespecified study autopsy template. We used Pearson's chi-squared test and logistic regression analysis with an alpha level of 0.05. Results: 221 patients were included in the main study (April 2015-April 2017) and 207 did not survive. Of these, 114 (55%, 64 control and 50 intervention) underwent medical (N = 73) or forensic (N = 41) autopsy. The cause of CA was cardiac 53%, respiratory 17%, overdose/intoxication 14%, ruptured aorta 10%, neurological 1%, and other 5%. There were no differences between control and intervention in the incidence of rib fractures (67% vs 72%; p-value = 0.58), or sternal fractures (44% vs 48%; p-value = 0.65), respectively. The most frequent non-skeletal complication was bleeding (26% of all patients) and intrathoracic was the most common location. Ten of the 114 patients had internal organ injuries, where lungs were most affected. Conclusion: In non-survivors of OHCA patients, the most frequent cause of cardiac arrest was cardiogenic. Skeletal and non-skeletal fractures/injuries were found in both control and intervention groups. Bleeding was the most common non-skeletal complication. Internal organ injuries were rare.

Ventilation during continuous compressions or at 30:2 compression-to-ventilation ratio results in similar arterial oxygen and carbon dioxide levels in an experimental model of prolonged cardiac arrest.

BACKGROUND: In refractory out-of-hospital cardiac arrest, transportation to hospital with continuous chest compressions (CCC) from a chest compression device and ventilation with 100% oxygen through an advanced airway is common practice. Despite this, many patients are hypoxic and hypercapnic on arrival, possibly related to suboptimal ventilation due to the counterpressure caused by the CCC. We hypothesized that a compression/ventilation ratio of 30:2 would provide better ventilation and gas exchange compared to asynchronous CCC during prolonged experimental cardiopulmonary resuscitation (CPR). METHODS: We randomized 30 anaesthetized domestic swine (weight approximately 50 kg) with electrically induced ventricular fibrillation to the CCC or 30:2 group and bag-valve ventilation with a fraction of inspired oxygen (FiO2) of 100%. We started CPR after a 5-min no-flow period and continued until 40 min from the induction of ventricular fibrillation. Chest compressions were performed with a Stryker Medical LUCAS® 2 mechanical chest compression device. We collected arterial blood gas samples every 5 min during the CPR, measured ventilation distribution during the CPR using electrical impedance tomography (EIT) and analysed post-mortem computed tomography (CT) scans for differences in lung aeration status. RESULTS: The median (interquartile range [IQR]) partial pressure of oxygen (PaO2) at 30 min was 110 (52-117) mmHg for the 30:2 group and 70 (40-171) mmHg for the CCC group. The median (IQR) partial pressure of carbon dioxide (PaCO2) at 30 min was 70 (45-85) mmHg for the 30:2 group and 68 (42-84) mmHg for the CCC group. No statistically significant differences between the groups in PaO2 (p = 0.40), PaCO2 (p = 0.79), lactate (p = 0.37), mean arterial pressure (MAP) (p = 0.47) or EtCO2 (p = 0.19) analysed with a linear mixed model were found. We found a deteriorating trend in PaO2, EtCO2 and MAP and rising PaCO2 and lactate levels through the intervention. There were no differences between the groups in the distribution of ventilation in the EIT data or the post-mortem CT findings. CONCLUSIONS: The 30:2 and CCC protocols resulted in similar gas exchange and lung pathology in an experimental prolonged mechanical CPR model.

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

The data presented in this article relate to the research article, "Reliability of mechanical ventilation during continuous chest compressions: a crossover study of transport ventilators in a human cadaver model of CPR" [1]. This article contains raw data of continuous recordings of airflow, airway and esophageal pressure during the whole experiment. Data of mechanical ventilation was obtained under ongoing chest compressions and from repetitive measurements of pressure-volume curves. All signals are presented as raw time series data with a sample rate of 200Hz for flow and 500 Hz for pressure. Additionally, we hereby publish extracted time series recordings of force and compression depth from the used automated chest compression device. Concomitantly, we report tables with time stamps from our laboratory book by which the data can be sequenced into different phases of the study protocol. We also present a dataset of derived volumes which was used for statistical analysis in our research article together with the used exclusion list. The reported dataset can help to understand mechanical properties of Thiel-embalmed cadavers better and compare different models of cardiopulmonary resuscitation (CPR). Future research may use this data to translate our findings from bench to bedside. Our recordings may become useful in developing respiratory monitors for CPR, especially in prototyping and testing algorithms of such devices.

Comparison of Sustained Return of Spontaneous Circulation Rate Between Manual and Mechanical Chest Compression in Adult Cardiac Arrest.

Objective: This study aimed to compare the rates of sustained return of spontaneous circulation (ROSC) between manual and mechanical chest compression in adult non-traumatic cardiac arrest. Methods: A retrospective cohort study was conducted from 2017 to 2019. The medical records were reviewed in 227 cardiac arrest patients aged ≥18 years who experienced out-of-hospital cardiac arrest or cardiac arrest while visiting the emergency department (ED). The patients were divided into manual chest compression and mechanical chest compression groups. The two groups were compared in terms of baseline characteristics, time to arrive at the ED, time to basic life support, initial rhythm, time to defibrillation in the shockable group, time to the first dose of adrenaline, and possible cause of arrest. A multivariate logistic regression model was used to determine the factors associated with ROSC. Results: A total of 227 patients met the inclusion criteria:193 patients in the manual chest compression group and 34 patients in the mechanical chest compression group. The rate of sustained ROSC in the manual chest compression group was higher (43% vs 8.8%; P < 0.001). The significant factors associated with ROSC were witnessed cardiac arrest (odds ratio (OR) = 3.41; 95% confidence interval (CI) 0.94-12.4), ED arrival by basic ambulance service (OR = 1.93; 95% CI 0.86-4.35), cardiac arrest at the ED (OR = 3.69; 95% CI 1.73-7.88), and cardiac arrest from hypoxia (OR = 2.01; 95% CI 1.02-3.97). Conclusion: Mechanical chest compression was not associated with sustained ROSC and tended to be selectively used in patients with a prolonged duration of cardiac arrest.

Suction cup on a piston-based chest compression device improves coronary perfusion pressure and cerebral oxygenation during experimental cardiopulmonary resuscitation.

Introduction: The presented study aimed to investigate whether a mechanical chest compression piston device with a suction cup assisting chest recoil could impact the hemodynamic status when compared to a bare piston during cardiopulmonary resuscitation. Methods: 16 piglets were anesthetized and randomized into 2 groups. After 3 minutes of induced ventricular fibrillation, a LUCAS 3 device was used to perform chest compressions, in one group a suction cup was mounted on the device's piston, while in the other group, compressions were performed by the bare piston. The device was used in 30:2 mode and the animals were manually ventilated. Endpoints of the study were: end tidal carbon dioxide, coronary and cerebral perfusion pressures, and brain oxygenation (measured using near infrared spectroscopy). At the end of the protocol, the animals that got a return to spontaneous circulation were observed for 60 minutes, then euthanized. Results: No difference was found in end tidal carbon dioxide or tidal volumes. Coronary perfusion pressure and cerebral oxygenation were higher in the Suction cup group over the entire experiment time, while cerebral perfusion pressure was higher only in the last 5 minutes of CPR. A passive tidal volume (air going in and out the airways during compressions) was detected and found correlated to end tidal carbon dioxide. Conclusions: The use of a suction cup on a piston-based chest compression device did not increase end tidal carbon dioxide, but it was associated to a higher coronary perfusion pressure.

Manual chest compression pause duration for ventilations during prehospital advanced life support - An observational study to explore optimal ventilation pause duration for mechanical chest compression devices.

AIM: Mechanical chest compression devices in the 30:2 mode generally provide a pause of three seconds to give two insufflations without evidence supporting this pause duration. We aimed to explore the optimal pause duration by measuring the time needed for two insufflations, during advanced life support with manual compressions. METHODS: Prospectively collected data in the AmsteRdam REsuscitation STudies (ARREST) registry were analysed, including thoracic impedance signal and waveform capnography from manual defibrillators of the Amsterdam ambulance service. Compression pauses were analysed for number of insufflations, time interval from start of the compression pause to the end of the second insufflation, chest compression pause duration and ventilation subintervals. RESULTS: During 132 out-of-hospital cardiac arrests, 1619 manual chest compression pauses to ventilate were identified. In 1364 (84%) pauses, two insufflations were given. In 28% of these pauses, giving two insufflations took more than three seconds. The second insufflation is completed within 3.8 seconds in 90% and within 5 seconds in 97.5% of these pauses. An increasing likelihood of achieving two insufflations is seen with increasing compression pause duration up to five seconds. CONCLUSION: The optimal chest compression pause duration for mechanical chest compression devices in the 30:2 mode to provide two insufflations, appears to be five seconds, warranting further studies in the context of mechanical chest compression. A 5-second pause will allow providers to give two insufflations with a very high success rate. In addition, a 5-second pause can also be used for other interventions like rhythm checks and endotracheal intubation.

Back Plate Marking of a Mechanical Chest Compression Device to Reduce the Duration of Chest Compression Interruptions.

Objective: To compare the effectiveness of applying the back plate marking method vs the standard method, to a mechanical chest compression device, in regards to reducing the duration of chest compression interruptions during a simulated cardiac arrest. Methods: An experimental study, one group pretest posttest design, conducted in a university-based hospital from November 2020 to October 2021. The study recruited 20 participants including emergency medical residents and paramedics. The participants were randomized into three-person teams and applied the device in both standard and back plate marking methods in sequential order. Teams were required to use a mechanical chest compression device in a manikin-based OHCA simulation to assess performance. Results: The median time pause for the deployment of the upper part of the device was significantly reduced (16 vs 21s, P < 0.01) in the back plate marking method, as was the total pause for device deployment (31.5 vs 38.75s, P = 0.03) and the proportion of total hands-off time attributable to device application interruption (43.08% vs 49.18%, P = 0.02). There was no difference between groups in the duration of all compression interruptions (70.5 vs 82.75s, P = 0.20) and compression fractions (77.85 vs 76.91%, P = 0.19). Conclusion: The back plate marking method was a significantly reduced time of the deployment of the upper part of the device and in regards to the overall pause for device deployment, but there was no difference in CPR quality between the two methods.

Comparison of blood flow between two mechanical compression devices using ultrasound: Animal trial.

BACKGROUND: During manual chest compression, maintaining accurate compression depth and consistency is a challenge. Therefore, mechanical chest compression devices(mCCDs) have been increasingly incorporated in clinical practice. Evaluation and comparison of the efficacy of these devices is critical for extensive clinical application. Hence, this study compared the cardiopulmonary resuscitation(CPR) efficiency of two chest compression devices, LUCAS™ 3(Physio-Control, Redmond, USA) and Easy Pulse (Schiller Medizintechnik GMBH, Feldkirchen, Germany), in terms of blood flow using ultrasonography(USG) in a swine model. METHODS: A swine model was used to compare two mCCDs, LUCAS™ 3 and Easy Pulse. Cardiac arrest was induced by injecting potassium chloride(KCl) solution in eight male mongrel pigs and the animals were randomly divided into two groups. Mechanical CPR was provided to two groups using LUCAS™ 3(LUCAS™ 3 group) and Easy Pulse(Easy Pulse group). USG was used to measure hemodynamic parameters including femoral peak systolic velocity(PSV) and femoral artery diameters(diameter during systole and diastole). Blood flow rate was calculated by multiplying the PSV and cross-sectional area of the femoral artery during systole. The end-tidal carbon dioxide(EtCo2), chest compression depth was measured. Systolic blood pressure, mean blood pressure, and diastolic blood pressure were also measured using an arterial catheter. RESULTS: The chest compression depth was much deeper in LUCAS™ 3 group than Easy Pulse group(LUCAS™ 3: 6.80 cm; Easy Pulse: 3.279 cm, p < 0.001). However, EtCo2 was lower in the LUCAS™ 3 group(LUCAS™ 3: 19.8 mmHg; Easy Pulse: 33.4 mmHg, p < 0.001). The PSV was higher in the LUCAS™ 3 group(LUCAS™ 3: 67.6 cm s-1; Easy Pulse: 55.0 cm s-1, p < 0.001), while the systolic(LUCAS™ 3: 1.5 cm; Easy Pulse: 2.0 cm, p < 0.001) and diastolic diameters were larger in the Easy Pulse group(LUCAS™ 3: 0.4; Easy Pulse: 0.8 cm, p < 0.001). The femoral flood flow rate was also lower in the LUCAS™ 3 group(LUCAS™ 3: 32.55 cm3/s; Easy Pulse: 61.35 cm3/s, p < 0.001). CONCLUSION: The Easy Pulse had a shallower compression depth and slower PSV but had a wider systolic diameter in the femoral artery as compared to that in LUCAS™ 3. Blood flow and EtCo2 were higher in the easy pulse group probably because of the wider diameter. Therefore, an easy pulse may create and maintain more effective intrathoracic pressure.

A novel strategy sequentially linking mechanical cardiopulmonary resuscitation with extracorporeal cardiopulmonary resuscitation optimizes prognosis of refractory cardiac arrest: an illustrative case series.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) to support cardiopulmonary resuscitation (CPR), also known as extracorporeal cardiopulmonary resuscitation (ECPR), has shown encouraging results in refractory cardiac arrest (RCA) resuscitation. However, its therapeutic benefits are linked to instant and uninterrupted chest compression (CC), besides early implementation. Mechanical CC can overcome the shortcomings of conventional manual CC, including fatigue and labor consumption, and ensure adequate blood perfusion. A strategy sequentially linking mechanical CPR with ECPR may earn extra favorable outcomes. CASE SERIES: We present a four-case series with ages ranging from 8 to 94 years who presented with prolonged absences of return of spontaneous circulation (ROSC) after CA associated with acute fulminant myocarditis (AFM) and myocardial infarction (MI). All the cases received VA-ECMO (ROTAFLOW, Maquet) assisted ECPR, with intra-aortic balloon pump (IABP) or continuous renal replacement treatment (CRRT) appended if persistently low mean blood pressure (MAP) or ischemic kidney injury occurred. All patients have successfully weaned off ECMO and the assistant life support devices with complete neurological recovery. Three patients were discharged, except the 94-year-old patient who died of irreversible sepsis 20 days after ECMO weaning-off. These encouraging results will hopefully lead to more consideration of this lifesaving therapy model that sequentially integrates mechanical CPR with ECPR to rescue RCA related to reversible cardiac causes. CONCLUSIONS: This successful case series should lead to more consideration of an integrated lifesaving strategy sequentially linking mechanical cardiopulmonary resuscitation with ECPR, as an extra favorable prognosis of refractory cardiac arrest related to this approach can be achieved.

Mechanical chest compression devices under special circumstances.

AIM: According to the current resuscitation guidelines, the use of mechanical chest compression devices could be considered under special circumstances like transport with ongoing resuscitation or long-term resuscitation. The aim of this study was to investigate whether survival is improved using mechanical devices under such circumstances. METHODS: Out-of-hospital cardiac arrests from all high-quality data centres of the German Resuscitation Registry from 2007 to 2020 were investigated. The use of mechanical devices was compared separately for transport with ongoing resuscitation, prolonged resuscitation (>45 min), and resuscitation with fibrinolytic agents applied. Baseline characteristics, 30-day survival/discharged alive, and neurological function at discharge were analysed descriptively; and 30-day survival/discharged alive was additionally analysed using multivariate logistic regression. RESULTS: Overall, patients who were treated with a mechanical device tended to be younger and were significantly more likely to have a witnessed cardiac arrest and a shockable initial rhythm. During the study period, 4,851 patients were transported to hospital with ongoing resuscitation (devices used in 44.2%). The 30-day survival was equal (odds ratio, OR: 1.13, 95%-CI: 0.79-1.60). In 3,920 cases, a resuscitation duration > 45 min was documented (9.5% with device). When a device was used, 30-day survival was significantly increased (OR 2.33, 95%-CI: 1.30-4.15). Fibrinolytic agents were used in 2,106 patients (22.2% with device). Here, 30-day survival was significantly worse with a device (OR: 0.52, 95%-CI: 0.30-0.91). CONCLUSION: Mechanical devices are not associated with better survival when used during transport, but rescuer safety could still be an important argument for their use. Devices are associated with better survival in prolonged resuscitation, but worse survival when a fibrinolytic was used.

Efficacy of AutoPulse for Mechanical Chest Compression in Patients with Shock-Resistant Ventricular Fibrillation.

INTRODUCTION: Sudden cardiac arrest is one of the most common causes of death. In cases of shock-resistant ventricular fibrillation, immediate transport of patients to the hospital is essential and made possible with use of devices for mechanical chest compression. OBJECTIVES: The efficacy of AutoPulse in patients with shock-resistant ventricular fibrillation was studied. METHODS: This is a multicentre observational study on a population of 480,000, with 192 reported cases of out-of-hospital cardiac arrest. The study included patients with shock-resistant ventricular fibrillation defined as cardiac arrest secondary to ventricular fibrillation requiring ≥3 consecutive shocks. Eventually, 18 patients met the study criteria. RESULTS: The mean duration of resuscitation was 48.4±43 min, 55% of patients were handed over to the laboratory while still in cardiac arrest, 83.3% of them underwent angiography and, in 93.3% of them, infarction was confirmed. Coronary intervention was continued during mechanical resuscitation in 50.0% of patients, 60% of patients survived the procedure, and 27.8% of the patients survived. CONCLUSIONS: Resistant ventricular fibrillation suggests high likelihood of a coronary component to the cardiac arrest. AutoPulse is helpful in conducting resuscitation, allowing the time to arrival at hospital to be reduced.

Pectus excavatum and mechanical chest compression of a dangerous bond.

Pectus excavatum (PE) is a malformation of the chest characterized by a median depression of the sternum. The incidence of PE is between 0.1% and 0.8%. In the last decade mechanical chest compression devices (MCCD) became of particular interest in cardiopulmonary resuscitation. Different devices became available and this resulted in an increase in their use during CPR mainly for practical reasons. Despite their increasing use, little evidence existed for their effectiveness and little was known about complications. Skin lesions and fractures of sternum or ribs are the ones with the highest incidence. Whereas subdiaphragmatic lesions, in particular fatal liver injuries are uncommon and described only in few case reports. In a recent retrospective study, CT was used to determine the proper compression landmark and depth of cardiopulmonary resuscitation in PE patients. The authors showed that the mean Haller Index in PE patients was higher than in controls, thus exposing internal organs to a higher injury risk during standard CPR maneuvers. We report the first case, to our knowledge, of liver injury during mechanical CPR in a patient with PE. Awareness is being raised on tailoring mechanical CPR in patients with chest deformities. Further exploration is needed to determine if there is a strong correlation between mechanical CPR and organ damage in PE. We believe that this case highlights the importance of individualizing CPR techniques.

Mechanical active compression-decompression versus standard mechanical cardiopulmonary resuscitation: A randomised haemodynamic out-of-hospital cardiac arrest study.

BACKGROUND: Active compression-decompression cardiopulmonary resuscitation (ACD-CPR) utilises a suction cup to lift the chest-wall actively during the decompression phase (AD). We hypothesised that mechanical ACD-CPR (Intervention), with AD up to 30 mm above the sternal resting position, would generate better haemodynamic results than standard mechanical CPR (Control). METHODS: This out-of-hospital adult non-traumatic cardiac arrest trial was prospective, block-randomised and non-blinded. We included intubated patients with capnography recorded during mechanical CPR. Exclusion criteria were pregnancy, prisoners, and prior chest surgery. The primary endpoint was maximum tidal carbon dioxide partial pressure (pMTCO2) and secondary endpoints were oxygen saturation of cerebral tissue (SctO2), invasive arterial blood pressures and CPR-related injuries. Intervention device lifting force performance was categorised as Complete AD (≥30 Newtons) or Incomplete AD (≤10 Newtons). Haemodynamic data, analysed as one measurement for each parameter per ventilation (Observation Unit, OU) with non-linear regression statistics are reported as mean (standard deviation). A two-sided p-value < 0.05 was considered as statistically significant. RESULTS: Of 221 enrolled patients, 210 were deemed eligible (Control 109, Intervention 101). The Control vs. Intervention results showed no significant differences for pMTCO2: 29(17) vs 29(18) mmHg (p = 0.86), blood pressures during compressions: 111(45) vs. 101(68) mmHg (p = 0.93) and decompressions: 21(20) vs. 18(18) mmHg (p = 0.93) or for SctO2%: 55(36) vs. 57(9) (p = 0.42). The 48 patients who received Complete AD in > 50% of their OUs had higher SctO2 than Control patients: 58(11) vs. 55(36)% (p < 0.001). CONCLUSIONS: Mechanical ACD-CPR provided similar haemodynamic results to standard mechanical CPR. The Intervention device did not consistently provide Complete AD. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov identifier (NCT number): NCT02479152. The Haemodynamic Effects of Mechanical Standard and Active Chest Compression-decompression During Out-of-hospital CPR.

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.

AIM OF THE STUDY: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.