Digit preference and biased conclusions in cardiac arrest studies.

BACKGROUND: In cardiac arrest (CA), time is directly predictive of patients' prognosis. The increase in mortality resulting from delayed cardiopulmonary resuscitation has been quantified minute by minute. Times reported in CA management studies could reflect a timestamping bias referred to as "digit preference". This phenomenon leads to a preference for certain numerical values (such as 2, 5, or 10) over others (such as 13). Our objective was to investigate whether or not digit preference phenomenon could be observed in reported times of the day related to CA management, as noted in a national registry. METHODS: We analyzed data from the French National Electronic Registry of Cardiac Arrests. We analyzed twelve times-of-the-day corresponding to each of the main steps of CA management reported by the emergency physicians who managed the patients in prehospital settings. We postulated that if CA occurred at random times throughout the day, then we could expect to see events related to CA management occurring at a similar rate each minute of each hour of the day, at a fraction of 1/60. We compared the fraction of times reported as multiples of 15 (0, 15, 30, and 45 - on the hour, quarters, half hour) with the expected fraction of 4/60 (i.e. 4 × 1/60). MAIN RESULTS: A total of 47,211 times-of-the-day in relation to 6131 CA were analyzed. The most overrepresented numbers were: 0, with 3737 occurrences (8% vs 2% expected, p < 0.0001) and 30, with 2807 occurrences (6% vs 2% expected, p < 0.0001). Times-of-the-day as multiples of 15 were overrepresented (22% vs 7% expected, p < 0.0001). CONCLUSION: Prospectively collected times were considerably influenced by digit preference phenomenon. Studies that are not based on automatic time recordings and that have not evaluated and considered this bias should be interpretated with caution.

Frequency and impact of slow flow / no flow in primary percutaneous coronary intervention.

OBJECTIVE: To determine the frequency of slow/no flow in primary percutaneous coronary intervention, to know the clinical and angiographical predictors of the phenomenon, and to investigate the immediate impact of slow/no flow on haemodnamics. METHOD: The cross-sectional study was conducted at the National Institute of Cardiovascular Diseases, Karachi, from June 2018 to July 2019, and comprised patients presenting with ST elevation myocardial infarction who underwent primary percutaneous coronary intervention. Demographic and clinical details of the patients were recorded. The antegrade flow was assessed and determined using the thrombolysis in myocardial infarction criterion. Patients were assessed for the occurrence, predictors and impact of slow/no flow. Data was analysed using SPSS 21. RESULTS: Of the 559 patients, 441(78.9%) were males. The overall mean age of the sample was 55.86±11.07 years. Angiographical slow/no flow during the procedure occurred in 53 (9.5%) patients, while normal flow was achieved in 506(90.5%). The thrombolysis in myocardial infarction grade in the affected patients was 0 in 10(1.8%), 1 in 15(2.7%), and 2 in 28(5%) patients. Smoking status, prior myocardial infarction, prior heart failure, no history of pre-infarct angina, cerebrovascular disease, New York Heart Association class III or IV, Killip class III or IV, and lower ejection fraction were significant predictors of slow/no flow (p<0.05). The angiographical and procedural predictors were total occlusion of culprit vessel and high thrombus burden (p<0.05). Direct stenting and use of bare metal stents had significantly less chance of developing slow/no flow (p<0.05). The most common immediate impact was hypotension 26(49.1%) and bradyarrhythmia 5(9.4%). However, 2(3.8%) patients developed haemodnamically unstable ventricular tachycardia that resulted in mortality. CONCLUSIONS: Predictors on the basis of history and angiographical features can be taken into account to anticipate the occurrence of slow/no flow phenomenon.

Temporary Right Middle Lobe Occlusion with a Blocking Device to Enable Collateral Ventilation Measurement of the Right Major Fissure.

BACKGROUND: Absence of interlobar collateral ventilation is essential to achieve lobar volume reduction after endobronchial valve (EBV) treatment and can be assessed using the Chartis measurement. However, especially in lower lobe measurements, Chartis can be complicated by the "no-flow phenomenon", during which a sudden cessation of flow is observed, leading to an unreliable measurement. If this phenomenon occurs in the right lower lobe, when measuring collateral flow over the right major fissure, the entrance to the right middle lobe should be occluded, and the Chartis balloon should be placed in the right upper lobe. Both Watanabe spigots and balloon catheters can be used to achieve occlusion. OBJECTIVE: Our aim was to demonstrate that right middle lobe occlusion with a blocking device is helpful in obtaining a reliable Chartis outcome in case of the no-flow phenomenon in the right lower lobe. METHODS: We performed a retrospective analysis of patients scheduled for EBV treatment in an EBV registry between September 2016 and September 2019. RESULTS: We included 15 patients with severe emphysema (median age 63 years [range 47-73], 73% female, and FEV1 24% [range 19-36] of predicted), who required temporary middle lobe occlusion (12 Watanabe spigot, 3 balloon catheter). After occlusion, a reliable Chartis outcome was obtained in all patients. CONCLUSION: Temporary middle lobe occlusion using a blocking device is helpful in obtaining a reliable Chartis outcome in case of a right lower lobe no-flow phenomenon.

Defibrillator charging before rhythm analysis causes peri-shock pauses exceeding guideline recommended maximum 5 s : A randomized simulation trial.

INTRODUCTION: Charging defibrillators prior to analyzing heart rhythms may decrease the no-flow time during rhythm check pauses while resuscitating in cardiac arrest. Although this anticipatory method is already used in some centers little is known about its safety. This study was carried out to confirm the safety and feasibility of the anticipatory method. It was hypothesized that this anticipatory method results in shorter total no-flow times, while other parameters of defibrillation efficacy including defibrillator safety and minimization of peri-shock pauses are unchanged. METHODS: This manikin study assigned 243 medical students randomly to study groups, 121 to the anticipatory method and 122 to the recommended European Resuscitation Council (ERC) algorithm. Of these 237 students ultimately underwent training (112 anticipatory method vs. 125 ERC algorithm). Participants were assessed and video recorded during a simulated cardiac arrest scenario which included three different heart rhythms (ventricular fibrillation [VF], pulseless ventricular tachycardia [pVT], asystole) in randomized order. Video and software analyses were performed. Defibrillation safety was assessed using a 17-item checklist defined beforehand. RESULTS: A total of 203 simulated cardiac arrests (75 anticipatory method and 128 ERC 2010 algorithm) were analyzed. The anticipatory method did not significantly reduce no-flow time (25.8 s, standard deviation, SD 7.4 s vs. 27.4 s SD 8.4 s, p = 0.19); however, peri-shock pauses were significantly longer in the anticipatory group compared to the ERC 2010 group (9.5 s SD 2.8 s vs. 3.3 s SD 1.9 s, p < 0.001). No significant difference concerning defibrillation safety between the groups was observed according to the 17-item checklist (14.6 SD 1.6 vs. 15.0 SD 1.4, p = 0.07). CONCLUSION: Charging defibrillators before rhythm analysis did not decrease total no-flow time in simulated cardiac arrests but resulted in significantly longer peri-shock pauses exceeding 5 s. No significant differences in defibrillation safety were observed between the groups.

Effect of using a laryngeal tube on the no-flow time in a simulated, single-rescuer, basic life support setting with inexperienced users.

BACKGROUND: The laryngeal tube (LT) is a recommended alternative to endotracheal intubation during advanced life support (ALS). Its insertion is relatively simple; therefore, it may also serve as an alternative to bag mask ventilation (BMV) for untrained personnel performing basic life support (BLS). Data support the influence of LT on the no-flow time (NFT) compared with BMV during ALS in manikin studies. METHODS: We performed a manikin study to investigate the effect of using the LT for ventilation instead of BMV on the NFT during BLS in a prospective, randomized, single-rescuer study. All 209 participants were trained in BMV, but were inexperienced in using LT; each participant performed BLS during a 4-min time period. RESULTS: No significant difference in total NFT (LT: mean 81.1 ± 22.7 s; BMV: mean 83.2 ± 13.1 s, p = 0.414) was found; however, significant differences in the later periods of the scenario were identified. While ventilating with the LT, the proportion of chest compressions increased significantly from 67.2 to 73.2%, whereas the proportion of chest compressions increased only marginally when performing BMV. The quality of the chest compressions and the associated ventilation rate did not differ significantly. The mean tidal volume and mean minute volume were significantly lower when performing BMV. CONCLUSIONS: The NFT was significantly shorter in the later periods in a single-rescuer, cardiac arrest scenario when using an LT without previous training compared with BMV with previous training. A possible explanation for this result may be the complexity and workload of alternating tasks (e.g., time loss when reclining the head and positioning the mask for each ventilation during BMV).

Cardiac arrest related lung edema: examining the role of downtimes in transpulmonary thermodilution analysis.

Pulmonary edema and its association with low flow times has been observed in postcardiac arrest patients. However, diagnosis of distinct types of lung pathology is difficult.The aim of this study was to investigate pulmonary edema by transpulmonary thermodilution (TPTD) after out-of-hospital cardiac arrest (OHCA), and the correlation to downtimes. In this retrospective single-center study consecutive patients with return of spontaneous circulation (ROSC) following OHCA, age ≥ 18, and applied TPTD were enrolled. According to downtimes, patients were divided into a short and a long no-flow-time group, and data of TPTD were analysed. We identified 45 patients (n = 25 short no-flow time; n = 20 long no-flow time) who met the inclusion criteria. 24 h after ROSC, the extra vascular lung water index (EVLWI) was found to be lower in the group with short no-flow time compared to the group with long no-flow time (10.7 ± 3.5 ml/kg vs. 12.8 ± 3.9 ml/kg; p = 0.08) and remained at a similar level 48 h (10.9 ± 4.3 ml/kg vs. 12.9 ± 4.9 ml/kg; p = 0.25) and 72 h (11.1 ± 5.0 ml/kg vs. 13.9 ± 7.7 ml/kg; p = 0.27) post-ROSC. We found a statistically significant and moderate correlation between no-flow duration and EVLWI 48 h (r = 0.51; p = 0.002) and 72 h (r = 0.54; p = 0.004) post-ROSC. Pulmonary vascular permeability index (PVPI) was not correlated with downtimes. Our observation underlines the presence of cardiac arrest-related lung edema by determination of EVLWI. The duration of no-flow times is a relevant factor for increased extravascular lung water index.

An effort to reduce chest compression pauses during automated external defibrillator use among laypeople: A randomized partially blinded controlled trial.

Aim: To implement small methodological changes in basic life support (BLS) training to reduce unnecessary pauses during automated external defibrillator (AED) use. Methods: One hundred and two university students with no BLS knowledge were randomly allocated into three groups (control and 2 experimental groups). Both experimental groups received a two-hour BLS training. While the contents were identical in both groups, in one of them the reduction of no-flow time was focused on (focused no-flow group). The control group did not receive any training. Finally, all of them were evaluated in the same out-of-hospital cardiac arrest simulated scenario. The primary endpoint was the compression fraction. Results: Results from 78 participants were analysed (control group: 19; traditional group: 30; focused no-flow group: 29). The focused no-flow group achieved higher percentages of compression fraction (median: 56.0, interquartile rank (IQR): 53.5-58.5) than the traditional group (44.0, IQR: 42.0-47.0) and control group (52.0, IQR: 43.0-58.0) in the complete scenario. Participants from the control group performed compression-only cardiopulmonary resuscitation (CPR), while the other groups performed compression-ventilation CPR. CPR fraction was calculated, showing the fraction of time in which the participants were performing resuscitation manoeuvres. In this case, the focused no-flow group reached higher percentages of CPR fraction (77.6, IQR: 74.4-82.4) than the traditional group (61.9, IQR: 59.3-68.1) and the control group (52.0, IQR: 43.0-58.0). Conclusions: Laypeople having automated external defibrillation training focused on acting in anticipation of the AED prompts contributed to a reduction in chest compression pauses during an OHCA simulated scenario.

The no-flow phenomenon following drug-coated balloon angioplasty in a patient with chronic limb-threatening ischemia and a history of below-knee amputation.

The endovascular treatment using a drug-coated balloon (DCB) reduces restenosis and target vessel re-vascularization rate in patients with peripheral artery disease such as claudication and chronic limb-threatening ischemia (CLTI). However, its safety and efficacy in patients with post-below-knee amputation remain unknown. We had a patient with CLTI and a history of below-knee amputation, who suffered a no-flow phenomenon following DCB angioplasty that required above-knee amputation. DCB angioplasty might not be appropriate for those with severe CLTI and histories of amputation. Learning objective: The present report describes the risk of endovascular treatment using a drug-coated balloon for chronic limb-threatening ischemia patients with a below-knee amputated limb.

Quality of chest compressions during prehospital resuscitation phase from scene arrival to ambulance transport in out-of-hospital cardiac arrest.

AIM: Prehospital cardiopulmonary resuscitation is performed from scene arrival to hospital arrival. The diverse prehospital resuscitation phases can affect the quality of chest compressions. This study aimed to evaluate the dynamic changes in chest compression quality during prehospital resuscitation. METHODS: Adult out-of-hospital cardiac arrest patients treated without prehospital return of spontaneous circulation were included in Seoul between July 2020 and September 2021. The chest compressions quality was assessed using a real-time chest compression feedback device. The prehospital phase was divided by key events during the prehospital resuscitation timeline (phase 1: first 2 min after initiation of chest compression, phase 2: from the end of phase 1 to 1 min prior to ambulance departure; phase 3: from 1 min before to 1 min after ambulance departure; phase 4: from the end of phase 3 to hospital arrival). The main outcome was no-flow fraction. The no-flow fraction between prehospital phases was compared using repeated-measure analysis of variance. RESULTS: In total, 788 patients were included. Mean no-flow fraction was the highest in phase 3 (phase 1: 11.3% ± 13.8, phase 2: 19.3% ± 12.3, phase 3: 33.0% ± 34.9, phase 4: 18.7% ± 23.7, p < 0.001). The mean number of total no-flow events per minute was also the highest in phase 3. The minute-by-minute analysis showed that the no-flow fraction rapidly increased before ambulance departure and decreased during ambulance transport. CONCLUSION: Dynamic changes in chest compression quality were observed during prehospital resuscitation phase. The no-flow fraction was the highest from 1 min before to 1 min after ambulance departure.

Safety and feasibility of intravascular ultrasound guided zero-contrast percutaneous coronary intervention-A prospective study.

BACKGROUND: There are published reports of safety and feasibility of percutaneous coronary intervention (PCI) without contrast, using intravascular ultrasound (IVUS) and coronary physiology guidance in chronic kidney disease population. We prospectively evaluated the safety and feasibility of zero-contrast PCI technique. METHODS: In this prospective study, we hypothesized that PCI is feasible without contrast, using IVUS guidance alone without mandatory coronary physiology to rule out slow-flow or no-flow at the end of PCI in a population at risk of contrast-induced acute kidney injury (CI-AKI). In this study, we included 31 vessels in 27 patients at risk of CI-AKI and assessed the primary outcome of technical success at the end of PCI. Major adverse cardio-cerebro vascular events (MACCE) and percent change in estimated glomerular filtration rate(eGFR) one month after PCI were the secondary outcomes of the study. RESULTS: The primary outcome was met in 87.1%(n = 27) of the procedures. Technical failure was seen in 12.9%(n = 4) of the procedures. None of the patients developed MACCE at one-month follow-up. The median percent change in eGFR at one-month follow-up was -8.19%(-24.40%, +0.92%). There was no newer initiation of renal replacement therapy at one-month follow-up. CONCLUSIONS: Zero-contrast PCI is safe and feasible in selective coronary anatomies with IVUS guidance. Coronary physiology is not mandatory to rule out slow-flow or no-flow at the end of procedure. Contrast may be needed to tide over the crisis during the possible complications, namely slow-flow, geographical miss and intraprocedural thrombus.

The association between CPR quality of In-hospital resuscitation and sex: A hypothesis generating, prospective observational study.

Introduction: The relationship between sex and cardiopulmonary resuscitation (CPR) outcomes remains unclear. Particularly, questions remain regarding the potential contribution of unmeasured confounders. We aimed to examine the differences in the quality of chest compression delivered to men and women. Methods: Prospective study of observational data recorded during consecutive resuscitations occurring in a single tertiary center (Feb-1-2015 to Dec-31-2018) with real-time follow-up to hospital discharge. The studied variables included time in CPR, no-flow-time and fraction, compression rate and depth and release velocity. The primary study endpoint was the unadjusted association between patient sex and the chest compression quality (depth and rate). The secondary endpoint was the association between the various components of chest compression quality, sex, and survival to hospital discharge/neurologically intact survival. Results: Overall 260 in-hospital resuscitations (57.7% male patients) were included. Among these 100 (38.5%) achieved return of spontaneous circulation (ROSC) and 35 (13.5%) survived to hospital discharge. Female patients were significantly older. Ischemic heart disease and ventricular arrhythmias were more prevalent among males. Compression depth was greater in female vs male patients (54.9 ± 11.3 vs 51.7 ± 10.9 mm; p = 0.024). Other CPR quality-metrics were similar. The rates of ROSC, survival to hospital discharge and neurologically intact survival did not differ between males and females. Univariate analysis revealed no association between sex, quality metrics and outcomes. Discussion: Women received deeper chest compressions during in-hospital CPR. Our findings require corroboration in larger cohorts but nonetheless underscore the need to maintain high-quality CPR in all patients using real-time feedback devices. Future studies should also include data on ventilation rates and volumes which may contribute to survival outcomes.

Electrical rhythm degeneration in adults with out-of-hospital cardiac arrest according to the no-flow and bystander low-flow time.

AIMS: For out-of-hospital cardiac arrest (OHCA) patients, the influence of the delay before the initiation of resuscitation, termed the no-flow time (NFT), and duration of bystander-only resuscitation low-flow time (BLFT) on the type of electrical rhythm observed has not been well described. The objective of this study is to determine the relationship between NFT, BLFT and the likelihood of a shockable rhythm over time. METHODS: Using a North American prospective registry (2005-2015; mostly urban settings), we selected adult (18 years and over) patients who experienced a witnessed OHCA from a suspected cardiac etiology. Patients with an emergency medical services witnessed OHCA were only included in sensitivity analyses. The association between the NFT, BLFT and the presence of a shockable rhythm was evaluated using a multivariable logistic regression adjusting for the registry version, age, sex, and public location. RESULTS: A total of 229,632 patients were logged in the registry, 50,957 of whom were included. Of these, 17,704 (34.7%) had an initial shockable rhythm. After the first minute, a significant decrease over time in the occurrence of shockable rhythm is observed but is slower when bystander cardiopulmonary resuscitation (CPR) is provided (each supplemental minute of BLFT: adjusted odds ratio = 0.95, 95 %CI = 0.94-0.95; each supplemental minute of NFT: adjusted odds ratio = 0.91, 95 %CI = 0.90-0.91]). CONCLUSIONS: In this large observational study, we were able to demonstrate that longer NFT were associated with lower odds of shockable presenting rhythms. Bystander CPR significantly mitigates the degradation of shockable rhythms over time, strengthening the need to improve bystander CPR rates around the world.

Dynamic Compression Induced Solidification.

This study presents a method for the determination of the dynamic pressure-dependent solidification of polycarbonate (PC) during flow using high pressure capillary rheometer (HPC) measurements. In addition, the pressure-dependent solidification was determined by isothermal pressure-volume-temperature (pvT) measurements under static conditions without shear. Independent of the compression velocity, a linear increase of the solidification pressure with temperature could be determined. Furthermore, the results indicate that the relaxation time at a constant temperature and compression rate can increase to such an extent that the material can no longer follow within the time scale specified by the compression rate. Consequently, the flow through the capillary stops at a specific pressure, with higher compression rates resulting in lower solidification pressures. Consequently, in regard to HPC measurements, it could be shown that the evaluation of the pressure via a pressure hole can lead to measurement errors in the limit range. Since the filling process in injection molding usually takes place under such transient conditions, the results are likely to be relevant for modelling the flow processes of thin-walled and microstructures with high aspect ratios.

Extracorporeal cardiopulmonary resuscitation without target temperature management for out-of-hospital cardiac arrest patients prolongs the therapeutic time window: a retrospective analysis of a nationwide multicentre observational study in Japan.

BACKGROUND: Extracorporeal cardiopulmonary resuscitation (ECPR) with extracorporeal membrane oxygenation (ECMO) is a promising therapy for out-of-hospital cardiac arrest (OHCA) compared with conventional cardiopulmonary resuscitation (CCPR). The no and low-flow time (NLT), the interval from collapse to reperfusion to starting ECMO or to the return of spontaneous circulation (ROSC) in CCPR, is associated with the neurological outcome of OHCA. Because the effects of target temperature management (TTM) on the outcomes of ECPR are unclear, we compared the neurological outcomes of OHCA between ECPR and CCPR without TTM. METHODS: We performed retrospective subanalyses of the Japanese Association for Acute Medicine OHCA registry. Witnessed cases of adult cardiogenic OHCA without TTM were selected. We performed univariate, multivariable and propensity score analyses to compare the neurological outcomes after ECPR or CCPR in all eligible patients and in patients with NLT of > 30 min or > 45 min. RESULTS: We analysed 2585 cases. Propensity score analysis showed negative result in all patients (odds ratio 0.328 [95% confidence interval 0.141-0.761], P = 0.010). However, significant associated with better neurological outcome was shown in patients with NLT of > 30 min or > 45 min (odds ratio 2.977 [95% confidence interval 1.056-8.388], P = 0.039, odds ratio 5.099 [95% confidence interval 1.259-20.657], P = 0.023, respectively). CONCLUSION: This study revealed significant differences in the neurological outcomes between ECPR and CCPR without TTM, in patients with NLT of > 30 min.

Association of ultrasound-related interruption during cardiopulmonary resuscitation with adult cardiac arrest outcomes: A video-reviewed retrospective study.

OBJECTIVES: To determine the association of focused transthoracic echocardiography (ECHO) related interruption during cardiopulmonary resuscitation (CPR) with patient outcomes in the Emergency Department (ED). METHODS: This was a retrospective, single center, cohort study, conducted in an urban community teaching ED. Eligible study subjects were adult patients in the ED with sustained cardiac arrest. Exclusion criteria include traumatic cardiac arrest and age less than 18. All resuscitations were video recorded and were subsequently reviewed by 2 study investigators. The no-flow time from chest compression interruption was analyzed using video review and separated into ECHO-related and non-ECHO related. Our primary outcome was patient survival to hospital discharge and the secondary outcome was the rate of return of spontaneous circulation (ROSC). Multivariate logistic regression analyses were performed to examine the associations between independent variables and outcomes. RESULTS: From January 2016 to May 2017, a total of 210 patients were included for final analysis. The median total no-flow time observed on video was 99.5 s (IQR: 54.0-160.0 s). Among these, a median of 26.5 s (IQR: 0.0-59.0 s) was ECHO-related and a median of 60.5 s (IQR: 34.0-101.9) was non-ECHO-related. The ECHO-related no-flow time between 77 and 122 s (OR: 7.31, 95 % confidence interval [CI]: 1.59-33.59; p-value = 0.01) and ECHO-related interruption ≦ 2 times (OR: 8.22, 95% CI: 1.51-44.64; p-value = 0.01) were positively associated with survival to hospital discharge. ECHO-related interruption ≦ 2 times (OR: 5.55, 95% CI: 2.44-12.61; p-value < 0.001) was also positively associated with ROSC. CONCLUSION: Short ECHO-related interruption during CPR was positively associated with ROSC and survival to hospital discharge. While ECHO can be a valuable diagnostic tool during CPR, the no-flow time associated with ECHO should be minimized.

Impacts of chest compression cycle length and real-time feedback with a CPRmeter® on chest compression quality in out-of-hospital cardiac arrest: study protocol for a multicenter randomized controlled factorial plan trial.

BACKGROUND: With a survival rate of 6 to 11%, out-of-hospital cardiac arrest (OHCA) remains a healthcare challenge with room for improvement in morbidity and mortality. The guidelines emphasize the highest possible quality of cardiopulmonary resuscitation (CPR) and chest compressions (CC). It is essential to minimize CC interruptions, and therefore increase the chest compression fraction (CCF), as this is an independent factor for survival. Survival is significantly and positively correlated with the suitability of CCF targets, CC frequency, CC depth, and brief predefibrillation pause. CC guidance improves adherence to recommendations and allows closer alignment with the CC objectives. The possibility of improving CCF by lengthening the time between two CC relays and the effect of real-time feedback on the quality of the CC must be investigated. METHODS: Using a 2 × 2 factorial design in a multicenter randomized trial, two hypotheses will be tested simultaneously: (i) a 4-min relay rhythm improves the CCF (reducing the no-flow time) compared to the currently recommended 2-min relay rate, and (ii) a guiding tool improves the quality of CC. Primary outcomes (i) CCF and (ii) correct compression score will be recorded by a real-time feedback device. Five hundred adult nontraumatic OHCAs will be included over 2 years. Patients will be randomized in a 1:1:1:1 distribution receiving advanced CPR as follows: 2-min blind, 2 min with guidance, 4-min blind, or 4 min with guidance. Secondary outcomes are the depth, frequency, and release of CC; length (care, no-flow, and low-flow); rate of return of spontaneous circulation; characteristics of advanced CPR; survival at hospital admission; survival and neurological state on days 1 and 30 (or intensive care discharge); and dosage of neuron-specific enolase on days 1 and 3. DISCUSSION: This study will contribute to assessing the impact of real-time feedback on CC quality in practical conditions of OHCA resuscitation. It will also provide insight into the feasibility of extending the relay rhythm between two rescuers from the currently recommended 2 to 4 min. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03817892 . Registered on 28 January 2019.

No flow meter method for measuring radon exhalation from the medium surface with a ventilation chamber.

The method for measuring radon exhalation rate from the medium surface with a ventilation chamber is un-replaceable when surveying the radon exhalation rate continuously. Generally, the pump flow rate is an important parameter to obtain the radon exhalation rate from the measurement model. Our previous research indicated that the results of those measurements are inaccurate when the air change rate is not far larger than the effective decay constant. A no flow meter method is proposed for measuring radon exhalation from the medium surface with a ventilation chamber. A constant K is used to replace the sum of the air change rate and the effective decay constant. The radon exhalation rate and the value of K can be obtained by nonlinear data fitting through a novel model. The air flow rate is not a parameter of this model, and the flow meter is unnecessary in this measurement. The radon exhalation rates obtained by verification experiments are within the accepted values for the reference value. This method can be applied to develop and improve the instruments for measuring radon exhalation rate.

Outcomes Following Percutaneous Coronary Intervention in Saphenous Vein Grafts With and Without Embolic Protection Devices.

OBJECTIVES: The aim of this study was to describe the early (inpatient and 30-day) and late (1-year) outcomes of percutaneous coronary intervention (PCI) in saphenous vein grafts (SVGs), with and without the use of embolic protection devices (EPD), in a large, contemporary, unselected national cohort from the database of the British Cardiovascular Intervention Society. BACKGROUND: There are limited, and discrepant, data on the clinical benefits of the adjunctive use of EPDs during PCI to SVGs in the contemporary era. METHODS: A longitudinal cohort of patients (2007 to 2014, n = 20,642) who underwent PCI to SVGs in the British Cardiovascular Intervention Society database was formed. Clinical, demographic, procedural, and outcome data were analyzed by dividing into 2 groups: no EPD (PCI to SVGs without EPDs, n = 17,730) and EPD (PCI to SVGs with EPDs, n = 2,912). RESULTS: Patients in the EPD group were older, had more comorbidities, and had a higher prevalence of moderate to severe left ventricular systolic dysfunction. Mortality was lower in the EPD group during hospital admission (0.70% vs. 1.29%; p = 0.008) and at 30 days (1.44% vs. 2.01%; p = 0.04) but similar at 1 year (6.22% vs. 6.01%; p = 0.67). Following multivariate analyses, no significant difference in mortality was observed during index admission (odds ratio [OR]: 0.71; 95% confidence interval [CI]: 0.42 to 1.19; p = 0.19), at 30 days (OR: 0.87; 95% CI: 0.60 to 1.25; p = 0.45), and at 1 year (OR: 0.92; 95% CI: 0.77 to 1.11; p = 0.41), along with similar rates of in-hospital major adverse cardiovascular events (OR: 1.16; 95% CI: 0.83 to 1.62; p = 0.39) and stroke (OR: 0.68; 95% CI: 0.20 to 2.35; p = 0.54). In propensity score-matched analyses, lower inpatient mortality was observed in the EPD group (OR: 0.46; 95% CI: 0.13 to 0.80; p = 0.002), although the adjusted risk for the periprocedural no-reflow or slow-flow phenomenon was higher in patients in whom EPDs were used (OR: 2.16; 95% CI: 1.71 to 2.73; p < 0.001). CONCLUSIONS: In this contemporary cohort, EPDs were used more commonly in higher risk patients but were associated with similar clinical outcomes in multivariate analyses. Lower inpatient mortality was observed in the EPD group in univariate and propensity score-matched analyses.

Is initial rhythm in OHCA a predictor of preceding no flow time? Implications for bystander response and ECPR candidacy evaluation.

OBJECTIVE: Shockable cardiac rhythms are associated with improved outcomes among out-of-hospital cardiac arrests (OHCA). Initial cardiac rhythm may also be predictive of a short preceding no-flow duration. We examined the relationship between no-flow duration and initial cardiac rhythm, which may demonstrate the urgency in rescuer response and assist with candidacy evaluation for extracorporeal-cardiopulmonary resuscitation (ECPR). METHODS: We examined consecutive adult OHCA's identified by a prospective registry in British Columbia (2005-2016). We included those with witnessed OHCA but no bystander CPR. The variable of interest was no-flow duration, defined as time from 9-1-1 call to EMS arrival. We fit an adjusted logistic regression model to estimate the association of no-flow duration and initial cardiac rhythm. Among those with shockable initial rhythms, we calculated the cumulative proportion with no-flow durations under incremental time cut-offs. RESULTS: Of 26 621 EMS-treated OHCA's, 2532 were included. Overall survival was 13.8%, and 34% had initial shockable rhythms. The probability of having an initial shockable rhythm decreased with increasing no-flow durations (adjusted OR 0.88 per minute, 95% CI 0.85-0.91). Among those found with initial shockable rhythms, 94% (95% CI 92-96%) had a no-flow time under 10 min. CONCLUSION: The odds of a shockable initial rhythm declined with each additional minute of no-flow time, highlighting the importance of early access to defibrillation. Among those with initial shockable rhythms, the preceding no-flow duration was highly likely to be under 10 min, which may inform decisions about ECPR candidacy among select patients with unwitnessed arrests.

Cardiopulmonary resuscitation duration and survival in out-of-hospital cardiac arrest patients.

AIM: Relationship between cardiopulmonary arrest and resuscitation (CPR) durations and survival after out-of-hospital cardiac arrest (OHCA) remain unclear. Our primary aim was to determine the association between survival without neurologic sequelae and cardiac arrest intervals in the setting of witnessed OHCA. METHODS: We analyzed 27,301 non-traumatic, witnessed OHCA patients in France included in the national registry from June 1, 2011 through December 1, 2015. We analyzed cardiac arrest intervals, designated as no-flow (NF; from collapse to start of CPR) and low-flow (LF; from start of CPR to cessation of resuscitation) in relation to 30-day survival without sequelae. We determined the influence of recognized prognostic factors (age, gender, initial rhythm, location of cardiac arrest) on this relation. RESULTS: For the entire cohort, the area delimited by a value of NF greater than 12min (95% confidence interval: 11-13min) and LF greater than 33min (95% confidence interval: 29-45min), yielded a probability of 30-day survival of less than 1%. These sets of values were greatly influenced by initial cardiac arrest rhythm, age, sex and location of cardiac arrest. Extended CPR duration (greater than 40min) in the setting of initial shockable cardiac rhythm is associated with greater than 1% survival with NF less than 18min. The NF interval was highly influential on the LF interval regardless of outcome, whether return of spontaneous circulation (p<0.001) or death (p<0.001). CONCLUSION: NF duration must be considered in determining CPR duration in OHCA patients. The knowledge of (NF, LF) curves as function of age, initial rhythm, location of cardiac arrest or gender may aid in decision-making vis-à-vis the termination of CPR or employment of advanced techniques.