Transthoracic impedance variability to assess quality of chest compression in out-of-hospital cardiac arrest.

BACKGROUND: Chest compression is a lifesaving intervention in out-of-hospital cardiac arrest (OHCA), but the optimal metrics to assess its quality have yet to be identified. The objective of this study was to investigate whether a new parameter, that is, the variability of the chest compression-generated transthoracic impedance (TTI), namely ImpCC , which measures the consistency of the chest compression maneuver, relates to resuscitation outcome. METHODS: This multicenter observational, retrospective study included OHCAs with shockable rhythm. ImpCC variability was evaluated with the power spectral density analysis of the TTI. Multivariate regression model was used to examine the impact of ImpCC variability on defibrillation success. Secondary outcome measures were return of spontaneous circulation and survival. RESULTS: Among 835 treated OHCAs, 680 met inclusion criteria and 565 matched long-term outcomes. ImpCC was significantly higher in patients with unsuccessful defibrillation compared to those with successful defibrillation (p = .0002). Lower ImpCC variability was associated with successful defibrillation with an odds ratio (OR) of 0.993 (95% confidence interval [95% CI], 0.989-0.998, p = .003), while the standard chest compression fraction (CCF) was not associated (OR 1.008 [95 % CI, 0.992-1.026, p = .33]). Neither ImpCC nor CCF was associated with long-term outcomes. CONCLUSIONS: In this population, consistency of chest compression maneuver, measured by variability in TTI, was an independent predictor of defibrillation outcome. ImpCC may be a useful novel metrics for improving quality of care in OHCA.

Proportional Versus Fixed Chest Compression Depth for Guideline-Compliant Resuscitation of Infant Asphyxial Cardiac Arrest.

OBJECTIVES: Current guidelines for parameters of the delivery of chest compressions (CC) for infants and children are largely consensus based. Of the two recommended depth targets - 1.5 inches and 1/3 anterior-posterior chest diameter (APD) - it is unclear whether these have equal potential for injury. In previous experiments, our group showed in an animal model of pediatric asphyxial out-of-hospital cardiac arrest (OHCA; modeling ∼ 7 year-old children) that 1/3 APD resulted in significantly deeper CC and a higher likelihood of life-threatening injury. We sought to examine and compare injury characteristics of CC delivered at 1.5 inches or 1/3 APD in an infant model of asphyxial OHCA. METHODS: Swine were sedated, anesthetized, paralyzed, intubated through direct laryngoscopy, and then mechanically ventilated (10ml/kg, FiO2:21%). APD was measured and confirmed by two investigators via a sliding T-square at the xiphoid. After instrumentation for vital signs monitoring, and while still anesthetized, the endotracheal tube was manually occluded to induce asphyxia, and occlusion was maintained for 9 minutes. Animals were then randomized to receive CC with a depth of 1.5 inches (Group 1) or 1/3 APD (Group 2), both with a rate of 100 per minute. Advanced life support drugs were administered at 13 minutes, and defibrillation at 14 minutes. Resuscitation continued until return of spontaneous circulation (ROSC) or 20 minutes of failed resuscitation. Survivors were sacrificed with KCl after 20 minutes of observation. Veterinary staff conducted necropsy to assay lung injury, rib fracture, hemothorax, airway bleeding, great vessel dissection, and heart/liver/spleen contusion. Injury characteristics were summarized and compared via Chi-Squared test or Mann-Whitney U-test using an alpha = 0.05. RESULTS: A total of 36 animals were included for analysis (Group 1: 18; Group 2: 18). Mean (SD) APD overall was 5.58 (0.23) inches, yielding a mean 1/3 APD depth of 1.86 inches. APD did not differ between groups. ROSC rates did not differ between groups. No injury characteristics differed significantly between groups. CONCLUSIONS: In an swine model of infant asphyxial OHCA and resuscitation considering 1/3 APD or 1.5 inches, neither CC depth strategy was associated with increased injury.

A novel CPR-assist device vs. established chest compression techniques in infant CPR: A manikin study.

INTRODUCTION: Guidelines for infant CPR recommend the two-thumb encircling hands technique (TTT) and the two-finger technique (TFT) for chest compression. Some devices have been designed to assist with infant CPR, but are often not readily available. Syringe plungers may serve as an alternative infant CPR assist device given their availability in most hospitals. In this study, we aimed to determine whether CPR using a syringe plunger could improve CPR quality measurements on the Resusci-Baby manikin compared with traditional methods of infant CPR. METHODS: Compression area with a diameter of 1 to 2 cm is recommended in previous infant CPR device researches. In this is a randomized crossover manikin study, we examined the efficacy of the Syringe Plunger Technique (SPT) which uses the plunger of the 20 ml syringe with a 2 cm diameter flat piston, commonly available in hospital, for infant External Chest Compressions (ECC). Participants performed TTT, TFT and SPT ECC on Resusci® Baby QCPR® according to 2020 BLS guidelines. RESULTS: Sixty healthcare providers participated in this project. The median (IQR) ECC depths in the TTT, TFT and SPT in the first minute were 41 mm (40-42), 40 mm (38-41) and 40 mm (39-41), respectively, with p < 0.001. The median (IQR) ECC recoil in the TTT, TFT and SPT groups in the first minute was 15% (1-93), 64% (18-96) and 53% (8-95), respectively, with p = 0.003. The result in the second minute had similar findings. The SPT had the best QCPR score and less fatigue. CONCLUSION: The performance of chest compression depth and re-rebound ratio was statistically different among the three groups. TTT has good ECC depth and depth accuracy but poor recoil. TFT is the complete opposite. SPT can achieve a depth close to TTT and has a good recoil performance as TFT. Regarding comprehensive performance, SPT obtains the highest QCPR score, and SPT is also less fatigued. SPT may be an effective alternative technique for infant CPR.

Efficacy of bougie first approach for endotracheal intubation with video laryngoscopy during continuous chest compression: a randomized crossover manikin trial.

BACKGROUND: Endotracheal intubation is challenging during cardiopulmonary resuscitation, and video laryngoscopy has showed benefits for this procedure. The aim of this study was to compare the effectiveness of various intubation approaches, including the bougie first, preloaded bougie, endotracheal tube (ETT) with stylet, and ETT without stylet, on first-attempt success using video laryngoscopy during chest compression. METHODS: This was a randomized crossover trial conducted in a general tertiary teaching hospital. We included anesthesia residents in postgraduate year one to three who passed the screening test. Each resident performed intubation with video laryngoscopy using the four approaches in a randomized sequence on an adult manikin during continuous chest compression. The primary outcome was the first-attempt success defined as starting ventilation within a one minute. RESULTS: A total of 260 endotracheal intubations conducted by 65 residents were randomized and analyzed with 65 procedures in each group. First-attempt success occurred in 64 (98.5%), 57 (87.7%), 56 (86.2%), and 46 (70.8%) intubations in the bougie-first, preloaded bougie, ETT with stylet, and ETT without stylet approaches, respectively. The bougie-first approach had a significantly higher possibility of first-attempt success than the preloaded bougie approach [risk ratio (RR) 8.00, 95% confidence interval (CI) 1.03 to 62.16, P = 0.047], the ETT with stylet approach (RR 9.00, 95% CI 1.17 to 69.02, P = 0.035), and the ETT without stylet approach (RR 19.00, 95% CI 2.62 to 137.79, P = 0.004) in the generalized estimating equation logistic model accounting for clustering of intubations operated by the same resident. In addition, the bougie first approach did not result in prolonged intubation or increased self-reported difficulty among the study participants. CONCLUSIONS: The bougie first approach with video laryngoscopy had the highest possibility of first-attempt success during chest compression. These results helped inform the intubation approach during CPR. However, further studies in an actual clinical environment are warranted to validate these findings. TRIAL REGISTRATION: Clinicaltrials.gov; identifier: NCT05689125; date: January 18, 2023.

Evaluating Prone Cardiopulmonary Resuscitation Techniques in the Surgical Settings: A Systematic Review of Case Studies.

PURPOSE: Examine the prone cardiopulmonary resuscitation techniques in patients undergoing surgery. DESIGN: Systematic review. METHODS: Using the preferred reporting items for systematic reviews and meta-analysis guidelines, PubMed, CINAHL, Cochrane Library, Google Scholar, and gray literature databases were searched to obtain eligible studies. The methodological quality of the case studies was assessed using the tool proposed by Murad and colleagues. Case reports involving surgical patients in a prone position were included. FINDINGS: A total of 21 patients undergoing neurologic or spinal surgeries were evaluated. The most common cardiac rhythms observed before arrest were pulseless electrical activity, asystole, ventricular tachycardia, ventricular fibrillation, and sudden bradycardia. The etiologies of the cardiac arrests included venous air embolism, hemorrhagic shock, and hypovolemia. Posterior compressions at T7 to T9 vertebral segment, with or without counterpressure, were immediately instituted. Return of spontaneous circulation was achieved in each instance, with an average time to return of spontaneous circulation of 5.60 minutes. Using a quality assessment tool, we determined that all case reports were of high quality and exhibited a low risk of bias. CONCLUSIONS: Prone resuscitation during neurosurgical or spinal surgeries has demonstrated promising outcomes. Additionally, the findings of this review further emphasize the need to train health care personnel in the techniques of prone cardiopulmonary resuscitation.

Evaluating the Efficacy and Safety of the Thumper Device for Cardiac Arrest: A Systematic Literature Review and Meta-Analysis.

Background: Cardiopulmonary resuscitation (CPR) is a major rescue measure for cardiac arrest (CA) patients, and chest compression is the key to CPR. The Thumper device was designed to facilitate manual compression during CPR. However, current randomized controlled trials (RCTs) provide controversial findings on the efficacy of the Thumper device. Objectives: This meta-analysis aimed to compare the clinical benefits of using the Thumper device with manual chest compressions during the provision of CPR for patients in CA. Methods: Relevant studies were retrieved from various databases, including Ovid, PubMed, Web of Science, EMBASE, Cochrane, and CNKI, and by manually searching the reference lists of research and review articles. All RCTs published in either English or Chinese until June 31, 2020, were included in the meta-analysis. The odds ratios (ORs) and their 95% confidence intervals (95% CIs) for the return of spontaneous circulation (ROSC), survival rate (SR), and the incidence of rib fractures (RFs) were compared between the manual and Thumper chest compressions. Results: A total of 2164 records were identified, of which 16 were RCTs with an overall risk of bias ranging from low to medium classification. Following CPR, the odds ratios for ROSC, SR, and RF were significantly better for the Thumper chest compression with ORs of 2.56 (95% CI 2.11-3.11, I 2 = 0%), 4.06 (95% CI 2.77-5.93, I 2 = 0%), and 0.24 (95% CI 0.14-0.41, I 2 = 0%), respectively. Conclusions: The Thumper compression devices may improve patient outcome, when used at inhospital cardiac arrest. This review suggests a potential role for mechanical chest compression devices for in-hospital cardiac arrest, but there is an urgent need for high-quality research, particularly adequately powered randomised trials, to further examine this role.

Wider Dissemination of Simplified Chest Compression-Only Cardiopulmonary Resuscitation Training Combined With Conventional Cardiopulmonary Resuscitation Training and 10-Year Trends in Cardiopulmonary Resuscitation Performed by Bystanders in a City.

BACKGROUND: Little is known about how to effectively increase bystander cardiopulmonary resuscitation (CPR), so we evaluated the 10-year trend of the proportion of bystander CPR in an area with wide dissemination of chest compression-only CPR (CCCPR) training combined with conventional CPR training.Methods and Results: We conducted a descriptive study after a community intervention, using a prospective cohort from September 2010 to December 2019. The intervention consisted of disseminating CCCPR training combined with conventional CPR training in Toyonaka City since 2010. We analyzed all non-traumatic out-of-hospital cardiac arrest (OHCA) patients resuscitated by emergency medical service personnel. The primary outcome was the trend of the proportion of bystander CPR. We conducted multivariate logistic regression models and assessed the adjusted odds ratio (AOR) using a 95% confidence interval (CI) to determine bystander CPR trends. Since 2010, we have trained 168,053 inhabitants (41.9% of the total population of Toyonaka City). A total of 1,508 OHCA patients were included in the analysis. The proportion of bystander CPR did not change from 2010 (43.3%) to 2019 (40.0%; 1-year incremental AOR 1.02 [95% CI: 0.98-1.05]). CONCLUSIONS: The proportion of bystander CPR did not increase even after wider dissemination of CPR training. In addition to continuing wider dissemination of CPR training, other strategies such as the use of technology are necessary to increase bystander CPR.

Effect of the Brief Instructional Video Intervention on the Quality of Cardiopulmonary Resuscitation.

Background: Chest compressions are the basis of cardiopulmonary resuscitation (CPR), and high-quality chest compressions can improve survival rate in patients with out-of-hospital cardiac arrest. Although many efforts have been made to improve the quality of CPR in inexperienced adults, the results are still not high, especially during emergencies. The primary purpose of this study is to investigate whether a brief instructional chest compression-only CPR video could improve chest compression quality in inexperienced adults. Methods: One hundred adults with no CPR experience (age: 20.28 ± 2.28 years; women: 50, men: 50) participated in this study. Participants completed body composition and handgrip strength measurements, and performed two CPR quality tests on the Laerdal® Little Anne QCPR Manikin, namely without video-CPR (WV-CPR) and video-CPR (V-CPR). The WV-CPR quality test was performed first. After 2 minutes of continuous chest compression, the participants rested for 10 seconds and repeated 3 cycles (phase 1, phase 2, and phase 3). After resting for more than 72 hours, V-CPR quality test was conducted. During the V-CPR with video intervention, the participants also continued to compress the chest for 2 minutes, and then rested for 10 seconds, repeating 3 cycles. Results: In phase 1, compared with WV-CPR, the V-CPR has a significant increase (p < 0.001) in chest compression fraction (CCF) (56.31 ± 33.22% vs. 41.82 ± 32.30%) and percent of correct compression rate (PCCR) (96.17 ± 8.45% vs. 26.31 ± 37.55%). In addition, the V-CPR has significantly lower (p < 0.001) chest compression rate (CCR) (110.85 ± 2.40 cpm vs. 128.86 ± 24.52 cpm) and rating of perceived exertion (RPE) (11.89 ± 2.25 vs. 12.87 ± 2.25). For phases 2 through 3, V-CPR and WV-CPR achieved significant differences in CCF, CCD, CCR, PCCR, and RPE (p < 0.01). There were significant differences (p < 0.05) in CCF, CCD, chest compression rebound rate, and RPE among the different administration stages of both WV-CPR and V-CPR. Conclusions: The results of this study revealed that a brief instructional chest compression-only CPR video could improve chest compression quality for inexperienced adults by reducing fatigue and CCR, and increasing CCF and PCCR.

Tracheobronchial rupture in children due to chest compression.

A tracheobronchial rupture can be lethal. Its etiology in children varies and includes blunt trauma and iatrogenic injury. Most of the latter are associated with tracheal intubation, with other, iatrogenic causes scarcely being reported. We herein reported the first case of tracheobronchial rupture caused by chest compression during cardiopulmonary resuscitation. The present case highlights the importance of close follow-up after cardiopulmonary resuscitation, even if the patients are not intubated.

Continuous compression with asynchronous ventilation improves CPR prognosis? A meta-analysis from human and animal studies.

BACKGROUND: The cardiopulmonary resuscitation (CPR) compression to ventilation strategy remains controversial. We conducted a meta-analysis to compare the outcomes between continuous chest compressions CPR with asynchronous ventilation (CCC-CPR) and interrupted chest compressions CPR with synchronous ventilation (ICC-CPR) in cardiac arrest. METHODS: PubMed, Web of Science, Embase, MEDLINE (Ovid/LWW) and the Cochrane Libraries were searched up from inception to July 31, 2022. Human and animal studies comparing CCC-CPR versus ICC-CPR were included. Outcome variables were return of spontaneous circulation (ROSC), time to ROSC, survival to discharge, 1-month survival, survival at 4 h, good neurological function, mean arterial pressure (MAP) and other clinical parameters. Jadad Scale and Newcastle-Ottawa Scale were used to assess the study quality and risk of bias. RESULTS: The systematic search identified eight studies on humans and twelve studies on animal trials. There were no significant differences in ROSC (odd ratios [OR] 1.07; 95% confidence interval [CI]: 0.86-1.32; P = 0.55), survival to hospital discharge (OR 1.04; 95%CI 0.77-1.42; P = 0.79), 1-month survival (OR 1.07; 95%CI 0.84-1.36; P = 0.57), and good neurological outcome (OR 0.92; 95%CI 0.84-1.01, P = 0.09) between CCC-CPR and ICC-CPR in human studies. In animal trials, CCC-CPR had significantly higher rate of ROSC (OR = 1.81; 95% CI: 0.94-3.49; P = 0.07), survival at 4 h (OR 2.57; 95% CI: 1.16-5.72; P = 0.02) and MAP (mean difference [MD] 0.79, 95% CI: 0.04-1.53; P = 0.04), even though no significant differences in ROSC time, arterial potential of hydrogen (pH) and partial tension of carbon dioxide (PaCO2). CONCLUSION: CCC-CPR did not show superiority in human outcomes compared with ICC-CPR, but its effect value was significantly increased in animal experiments. We should take the positive outcomes from animals and apply them to human models, and more physiological mechanisms need to be confirmed in CPR patients with different compression-ventilation strategies to improve the prognosis of cardiac arrest.

Design and Evaluation of CPR Emergency Equipment for Non-Professionals.

Sudden cardiac death is a sudden and highly fatal condition. Implementing high-quality emergency cardiopulmonary resuscitation (CPR) early on is an effective rescue method for this disease. However, the rescue steps of CPR are complicated and difficult to remember, and the quantitative indicators are difficult to control, which leads to a poor quality of CPR emergency actions outside the hospital setting. Therefore, we have developed CPR emergency equipment with a multisensory feedback function, aiming to guide rescuers in performing CPR through visual, auditory, and tactile interaction. This equipment consists of three components: first aid clothing, an audio-visual integrated terminal, and a vital sign detector. These three components are based on a micro-power WiFi-Mesh network, enabling the long-term wireless transmission of the multisensor data. To evaluate the impact of the multisensory feedback CPR emergency equipment on nonprofessionals, we conducted a controlled experiment involving 32 nonmedical subjects. Each subject was assigned to either the experimental group, which used the equipment, or the control group, which did not. The main evaluation criteria were the chest compression (CC) depth, the CC rate, the precise depth of the CC ratio (5-6 cm), and the precise rate of the CC ratio -(100-120 times/min). The results indicated that the average CC depth in the experimental group was 51.5 ± 1.3 mm, which was significantly better than that of the control group (50.2 ± 2.2 mm, p = 0.012). Moreover, the average CC rate in the experimental group (110.1 ± 6.2 times/min) was significantly higher than that of the control group (100.4 ± 6.6 times/min) (p < 0.001). Compared to the control group (66.37%), the experimental group showed a higher proportion of precise CC depth (82.11%), which is closer to the standard CPR rate of 100%. In addition, the CC ratio of the precise rate was 93.75% in the experimental group, which was significantly better than that of 56.52% in the control group (p = 0.024). Following the experiment, the revised System Availability Scale (SUS) was utilized to evaluate the equipment's usability. The average total SUS score was 78.594, indicating that the equipment's acceptability range was evaluated as 'acceptable', and the overall adjective rating was 'good'. In conclusion, the multisensory feedback CPR emergency equipment significantly enhances the CC performance (CC depth, CC rate, the precise depth of CC ratio, the precise rate of CC ratio) of nonprofessionals during CPR, and the majority of participants perceive the equipment as being easy to use.

Impact of COVID-19-adapted guidelines using different airway management strategies on resuscitation quality in out-of-hospital-cardiac-arrest - a randomised manikin study.

BACKGROUND: Although airway management for paramedics has moved away from endotracheal intubation towards extraglottic airway devices in recent years, in the context of COVID-19, endotracheal intubation has seen a revival. Endotracheal intubation has been recommended again under the assumption that it provides better protection against aerosol liberation and infection risk for care providers than extraglottic airway devices accepting an increase in no-flow time and possibly worsen patient outcomes. METHODS: In this manikin study paramedics performed advanced cardiac life support with non-shockable (Non-VF) and shockable rhythms (VF) in four settings: ERC guidelines 2021 (control), COVID-19-guidelines using videolaryngoscopic intubation (COVID-19-intubation), laryngeal mask (COVID-19-Laryngeal-Mask) or a modified laryngeal mask modified with a shower cap (COVID-19-showercap) to reduce aerosol liberation simulated by a fog machine. Primary endpoint was no-flow-time, secondary endpoints included data on airway management as well as the participants' subjective assessment of aerosol release using a Likert-scale (0 = no release-10 = maximum release) were collected and statistically compared. Continuous Data was presented as mean ± standard deviation. Interval-scaled Data were presented as median and Q1 and Q3. RESULTS: A total of 120 resuscitation scenarios were completed. Compared to control (Non-VF:11 ± 3 s, VF:12 ± 3 s) application of COVID-19-adapted guidelines lead to prolonged no-flow times in all groups (COVID-19-Intubation: Non-VF:17 ± 11 s, VF:19 ± 5 s;p ≤ 0.001; COVID-19-laryngeal-mask: VF:15 ± 5 s,p ≤ 0.01; COVID-19-showercap: VF:15 ± 3 s,p ≤ 0.01). Compared to COVID-19-Intubation, the use of the laryngeal mask and its modification with a showercap both led to a reduction of no-flow-time(COVID-19-laryngeal-mask: Non-VF:p = 0.002;VF:p ≤ 0.001; COVID-19-Showercap: Non-VF:p ≤ 0.001;VF:p = 0.002) due to a reduced duration of intubation (COVID-19-Intubation: Non-VF:40 ± 19 s;VF:33 ± 17 s; both p ≤ 0.01 vs. control, COVID-19-Laryngeal-Mask (Non-VF:15 ± 7 s;VF:13 ± 5 s;p > 0.05) and COVID-19-Shower-cap (Non-VF:15 ± 5 s;VF:17 ± 5 s;p > 0.05). The participants rated aerosol liberation lowest in COVID-19-intubation (median:0;Q1:0,Q3:2;p < 0.001vs.COVID-19-laryngeal-mask and COVID-19-showercap) compared to COVID-19-shower-cap (median:3;Q1:1,Q3:3 p < 0.001vs.COVID-19-laryngeal-mask) or COVID-19-laryngeal-mask (median:9;Q1:6,Q3:8). CONCLUSIONS: COVID-19-adapted guidelines using videolaryngoscopic intubation lead to a prolongation of no-flow time. The use of a modified laryngeal mask with a shower cap seems to be a suitable compromise combining minimal impact on no-flowtime and reduced aerosol exposure for the involved providers.

A novel retraining strategy of chest compression skills for infant CPR results in high skill retention for longer.

Infant cardiopulmonary resuscitation (iCPR) is often poorly performed, predominantly because of ineffective learning, poor retention and decay of skills over time. The aim of this study was to investigate whether an individualized, competence-based approach to simulated iCPR retraining could result in high skill retention of infant chest compressions (iCC) at follow-up. An observational study with 118 healthcare students was conducted over 12 months from November 2019. Participants completed pediatric resuscitation training and a 2-min assessment on an infant mannequin. Participants returned for monthly assessment until iCC competence was achieved. Competence was determined by passing assessments in two consecutive months. After achieving competence, participants returned just at follow-up. For each 'FAIL' during assessment, up to six minutes of practice using real-time feedback was completed and the participant returned the following month. This continued until two consecutive monthly 'PASSES' were achieved, following which, the participant was deemed competent and returned just at follow-up. Primary outcome was retention of competence at follow-up. Descriptive statistics were used to analyze demographic data. Independent t-test or Mann-Whitney U test were used to analyze the baseline characteristics of those who dropped out compared to those remaining in the study. Differences between groups retaining competence at follow-up were determined using the Fisher exact test. On completion of training, 32 of 118 participants passed the assessment. Of those achieving iCC competence at month 1, 96% retained competence at 9-10 months; of those achieving competence at month 2, 86% demonstrated competence at 8-9 months; of those participants achieving competence at month 3, 67% retained competence at 7-8 months; for those achieving competence at month 4, 80% demonstrated retention at 6-7 months.   Conclusion: Becoming iCC competent after initial training results in high levels of skill retention at follow-up, regardless of how long it takes to achieve competence. What is Known: • Infant cardiopulmonary resuscitation (iCPR) is often poorly performed and skills decay within months after training. • Regular iCPR skills updates are important, but the optimal retraining interval considering individual training needs has yet to be established. What is New: • Infant chest compression (iCC) competence can be achieved within one to four months after training and once achieved, it can be retained for many months. • With skill reinforcement of up to 28 minutes after initial training, 90% of individuals were able to achieve competence in iCC and 86% retained this competence at follow-up.

Cardiopulmonary Resuscitation-associated Lung Edema (CRALE). A Translational Study.

Rationale: Cardiopulmonary resuscitation is the cornerstone of cardiac arrest (CA) treatment. However, lung injuries associated with it have been reported.Objectives: To assess 1) the presence and characteristics of lung abnormalities induced by cardiopulmonary resuscitation and 2) the role of mechanical and manual chest compression (CC) in its development.Methods: This translational study included 1) a porcine model of CA and cardiopulmonary resuscitation (n = 12) and 2) a multicenter cohort of patients with out-of-hospital CA undergoing mechanical or manual CC (n = 52). Lung computed tomography performed after resuscitation was assessed qualitatively and quantitatively along with respiratory mechanics and gas exchanges.Measurements and Main Results: The lung weight in the mechanical CC group was higher compared with the manual CC group in the experimental (431 ± 127 vs. 273 ± 66, P = 0.022) and clinical study (1,208 ± 630 vs. 837 ± 306, P = 0.006). The mechanical CC group showed significantly lower oxygenation (P = 0.043) and respiratory system compliance (P < 0.001) compared with the manual CC group in the experimental study. The variation of right atrial pressure was significantly higher in the mechanical compared with the manual CC group (54 ± 11 vs. 31 ± 6 mm Hg, P = 0.001) and significantly correlated with lung weight (r = 0.686, P = 0.026) and respiratory system compliance (r = -0.634, P = 0.027). Incidence of abnormal lung density was higher in patients treated with mechanical compared with manual CC (37% vs. 8%, P = 0.018).Conclusions: This study demonstrated the presence of cardiopulmonary resuscitation-associated lung edema in animals and in patients with out-of-hospital CA, which is more pronounced after mechanical as opposed to manual CC and correlates with higher swings of right atrial pressure during CC.

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.

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.

Chest compression quality during CPR of potential contagious patients wearing personal protection equipment.

AIM OF THE STUDY: In this study we aimed to investigate whether changing rescuers wearing N95 masks every 1 min instead of the standard CPR change over time of 2 min would make a difference in effective chest compressions. METHODS: This study was a randomized controlled mannequin study. Participants were selected from healthcare staff. They were divided into two groups of two people in each group. The scenario was implemented on CPR mannequin representing patient with asystolic arrest, that measured compression depth, compression rate, recoil, and correct hand position. Two different scenarios were prepared. In Scenario 1, the rescuers were asked to change chest compression after 1 min. In Scenario 2, standard CPR was applied. The participants' vital parameters, mean compression rate, correct compression rate/ratio, total number of compressions, compression depth, correct recoil/ratio, correct hand position/ratio, mean no-flow time, and total CPR time were recorded. RESULTS: The study hence included 14 teams each for scenarios, with a total of 56 participants. In each scenario, 14 participants were physicians and 14 participants were women. Although there was no difference in the first minute of the cycles starting from the fourth cycle, a statistically significant difference was observed in the second minute in all cycles except the fifth cycle. CONCLUSION: Changing the rescuer every 1 min instead of every 2 min while performing CPR with full PPE may prevent the decrease in compression quality that may occur as the resuscitation time gets longer.

Mechanical cardiopulmonary resuscitation in microgravity and hypergravity conditions: A manikin study during parabolic flight.

INTRODUCTION: Space travel is expected to grow in the near future, which could lead to a higher burden of sudden cardiac arrest (SCA) in astronauts. Current methods to perform cardiopulmonary resuscitation in microgravity perform below earth-based standards in terms of depth achieved and the ability to sustain chest compressions (CC). We hypothesised that an automated chest compression device (ACCD) delivers high-quality CC during simulated micro- and hypergravity conditions. METHODS: Data on CC depth, rate, release and position utilising an ACCD were collected continuously during a parabolic flight with alternating conditions of normogravity (1 G), hypergravity (1.8 G) and microgravity (0 G), performed on a training manikin fixed in place. Kruskal-Wallis and Mann-Withney U test were used for comparison purpose. RESULTS: Mechanical CC was performed continuously during the flight; no missed compressions or pauses were recorded. Mean depth of CC showed minimal but statistically significant variations in compression depth during the different phases of the parabolic flight (microgravity 49.9 ± 0.7, normogravity 49.9 ± 0.5 and hypergravity 50.1 ± 0.6 mm, p < 0.001). CONCLUSION: The use of an ACCD allows continuous delivery of high-quality CC in micro- and hypergravity as experienced in parabolic flight. The decision to bring extra load for a high impact and low likelihood event should be based on specifics of its crew's mission and health status, and the establishment of standard operating procedures.

Chest compression release velocity: An independent determinant of end-tidal carbon dioxide in out-of-hospital cardiac arrest.

BACKGROUND: Chest compression (CC) depth, CC rate and ventilatory rate (VR) are known to have an impact on end-tidal carbon dioxide (ETCO2) values. Chest compression release velocity (CCRV) is increasingly acknowledged as a novel metric in cardiopulmonary resuscitation (CPR). The objective of this study was to analyze whether CCRV would have any effect on ETCO2 values. METHODS: In out-of-hospital cardiac arrests (OHCA), effects of CC depth, CC rate, CCRV and VR on ETCO2 were analyzed through linear mixed effect models. A stratification was made on a CCRV of 300, 400 and 500 mm/s. In these categories, mean ETCO2 values were corrected for CC depth and compared through a one-way ANOVA. RESULTS: A 10 mm increase in CC depth was associated with a 1.5 mmHg increase in ETCO2 (p < 0.001), a 100 mm/s increase in CCRV with a 0.8 mmHg increase (p = 0.010) and a 5 breaths per minute increase in VR with a 2.0 mmHg decrease (p < 0.001). CC depth was strongly correlated with CCRV (Pearson's r = 0.709, p < 0.001). After adjusting for CC depth, ETCO2 was on average 6.5 mmHg higher at a CCRV of 500 than at 400 mm/s (p = 0.005) and 5.3 mmHg higher than at 300 mm/s (p = 0.033). CONCLUSIONS: In OHCA patients, higher CCRV values resulted in higher ETCO2 values. This effect is independent of CC depth, despite the strong correlation between CCRV and CC depth.

Quantitative assessment of chest compression techniques on an infant manikin.

BACKGROUND: Current cardiopulmonary resuscitation (CPR) guidelines recommend the two-finger technique (TFT) of chest compression (CC) in infants for a single rescuer. We hypothesized that healthcare providers cannot achieve adequate CC depth with TFT, even if using real-time visual feedback (RVF). METHODS: This was a cross-over study, randomizing participants to perform three sets of 2-min continuous CC, comparing (i) TFT with RVF, (ii) the one-hand technique (OHT) without RVF, and (iii) OHT with RVF. A standard CPR trainer manikin of a 3-month-old infant and a monitor/defibrillator that displays and records the quantitative CC quality were used. We set a target compression depth of 40-50 mm and a target compression rate of 100-120/min. Data were analyzed using the Friedman test and Bonferroni correction. Statistical significance was defined as P-value of< 0.05. RESULTS: Fifty-nine healthcare providers participated in the study. The mean compression depth was 24 mm (interquartile range [IQR], 22-26 mm) in TFT with RVF and 43 mm (IQR, 38-48 mm) in OHT without RVF, P < 0.001. The proportion of adequate CC depth was 0% (IQR, 0-0%) in TFT with RVF, 22% (IQR, 5-54%) in OHT without RVF, and 62% (IQR, 29-83%) in OHT with RVF. The mean compression rate was within the target range in all three techniques. CONCLUSIONS: The TFT cannot produce the CC depth that meets the recommendation of the current CPR guidelines for an infant with RVF, whereas the OHT does.