Low-flow Duration Research Articles

Initial Arterial pCO2 and Its Course in the First Hours of Extracorporeal Cardiopulmonary Resuscitation Show No Association with Recovery of Consciousness in Humans: A Single-Centre Retrospective Study

Background: Cardiac arrest is a severe condition with high mortality rates, especially in the case of prolonged low-flow durations resulting in severe ischaemia and reperfusion injury. Changes in partial carbon dioxide concentration (pCO2) may aggravate this injury. Extracorporeal cardiopulmonary resuscitation (ECPR) shortens the low-flow duration and enables close regulation of pCO2. We examined whether pCO2 is associated with recovery of consciousness. Methods: We retrospectively analysed ECPR patients ≥ 16 years old treated between 2010 and 2019. We evaluated initial arterial pCO2 and the course of pCO2 ≤ 6 h after initiation of ECPR. The primary outcome was the rate of recovery of consciousness, defined as Glasgow coma scale motor score of six. Results: Out of 99 ECPR patients, 84 patients were eligible for this study. The mean age was 47 years, 63% were male, 93% had a witnessed arrest, 45% had an out-of-hospital cardiac arrest, and 38% had a recovery of consciousness. Neither initial pCO2 (Odds Ratio (OR) 0.93, 95% confidence interval 95% (CI) 0.78–1.08) nor maximum decrease of pCO2 (OR 1.03, 95% CI 0.95–1.13) was associated with the recovery of consciousness. Conclusion: Initial arterial pCO2 and the course of pCO2 in the first six hours after initiation of ECPR were not associated with the recovery of consciousness.

Comparative assessment of environmental flow using hydrological methods of low flow indexes, Smakhtin, Tennant and flow duration curve

There are different methods in hydrological approach for estimating the environmental flow and a comparative assessment is necessary. The low flow indexes (7Q2 and 7Q10), Smakhtin, Tennent and flow duration curve were used to estimate the environmental flow of Zohreh River in the southwest of Iran. The Smakhtin, 7Q2, 7Q10 and Tennant methods resulted in the estimation of constant values of 27.2, 12.7, 5.9 and (8 and 24) cms, so that, on average 52.8, 26.9 and 12.3, 36.7 percent of the monthly flow is allocated to the environmental flow. The monthly environmental flow pattern for these methods does not fit well with the monthly flow pattern, and thus it can be concluded that the Smakhtin, 7Q2, 7Q10 and Tennant methods cannot be used in the initial form. The application of the flow duration curve leads to an environmental flow assessment in the range of 6.8–38 cms in different months, whose time pattern completely matched with the monthly flow pattern. In this method, on average, 30.8% (range 18–48%) of the monthly flow allocated to the environmental flow, which is reasonable and acceptable amounts. Investigating the results of this study shows that the time pattern of the results should be analyzed in comparison with the observational flow pattern to estimate the environmental flow with a hydrological approach. The results also suggest that the methods that provide a constant amount of environmental flow in different months of the year should be interpreted cautiously along with other methods.

Influence of demographic parameters and time delays among patients with ACS and OHCA in non-urban areas

Out-of-hospital cardiac arrest (OHCA) represents a major public health. Acute coronary syndrome (ACS) is the leading precipitant of collapse. Predictors of survival have been described in the literature. However, most studies have been conducted in city areas. Less is known about resuscitation performance of mobile medical team (MMT) in non-urban areas. Established in 1903, our institution was initially founded to treat patients suffering from tuberculosis. Built at the top of a hill, the location of the ancient sanatorium consists of rural areas with a low population density. To perform a quality control assessment on the management of OHCA after ACS in non-urban areas. To identify quantitative variables influencing 30-day outcome. Retrospective single-center study including 40 patients resuscitated from OHCA after ACS. Baseline characteristics, resuscitation settings, time delays, blood samples, cardiac findings and clinical outcomes were analyzed. 30-day mortality was more likely associated with the following parameters: age, no-bystander CPR, no use of AED, non-convertible rhythm, recurrent cardiac arrest, epinephrine dose, shock, lactate level, LVEF, culprit lesion, no-flow & low-flow duration, kilometres and time delays (MMT arrival, ER - CathLab - ICU admission). Particularly, high lactate, long duration of RCP, remoteness from hospital and prolonged pre-hospital management (MMT arrival, ER admission) were predictors of early mortality (see bold type in Table 1 ). Beyond the usual prognostic factors, it would appear that demographic parameters and time delays represent major determinants of mortality after OHCA in non-urban areas. Therefore, shortening response times and prompt delivery to hospital facilities may help to improve the prognosis, rather than prolonged pre-hospital care. Further RCTs are needed to assess the effect of the ‘scoop & run’ approach vs the ‘stay & play’ approach in this setting.

Applying Weibull distribution and Low Flow Frequency Curves for minimum flow prediction in an ungagged stream in Connecticut, New England

The necessity to conduct hydrological studies for water resources management, infrastructure design and, ecosystems protection can help mitigate flood and drought hazards. Prediction of low flows remains an important task for water management and ecosystems protection that can affect streams during low-flow periods. There have been many approaches to low flow prediction applying either statistical or deterministic methods, but there has not been any successful approach to link low flows between similar watersheds yet. The Fenton, Natchaug and Mount Hope Rivers watersheds are neighbors and are the major streams that discharge into the Mansfield Hollow Lake that belongs to the Thames River watershed, located in Northeast of the State of Connecticut in USA. A study to determine whether and how water withdrawals from the University’s Fenton River water supply wells affect the fisheries habitat of the Fenton River adjacent to the well field was conducted for four years at the beginning of 2002. The Mount Hope River was the only river with a long record of daily discharges available since the year 1940, meanwhile the Fenton and Natchaug River remained ungagged until the year 2006. This research developed and tested two mathematical models for the prediction of minimum discharges in the Fenton and Natchaug Rivers with the discharges available from the Mount Hope River. Yearly Low Flow Duration Curves (LFFC) and Weibull distribution methods were applied to the three rivers to predict the low flows in the Fenton and Natchaug Rivers taking as input the minimum flows and dates in the Mount Hope River. The results found that the Weibull distribution model showed a much better accuracy than the Low Flow Duration Curve method for the prediction of low flows discharges in the Fenton and Natchaug Rivers.

PROLOGUE (PROgnostication using LOGistic regression model for Unselected adult cardiac arrest patients in the Early stages): Development and validation of a scoring system for early prognostication in unselected adult cardiac arrest patients

BackgroundEarly prognostication after cardiac arrest would be useful. We aimed to develop a scoring model for early prognostication in unselected adult cardiac arrest patients. MethodsWe retrospectively analysed data of adult non-traumatic cardiac arrest patients treated at a tertiary hospital between 2014 and 2018. The primary outcome was poor outcome at hospital discharge (cerebral performance category, 3–5). Using multivariable logistic regression analysis, independent predictors were identified among known outcome predictors, that were available at intensive care unit admission, in patients admitted in the first 3 years (derivation set, N = 671), and a scoring system was developed with the variables that were retained in the final model. The scoring model was validated in patients admitted in the last 2 years (validation set, N = 311). ResultsThe poor outcome rates at hospital discharge were similar between the derivation (66.0%) and validation sets (64.3%). Age <59 years, witnessed collapse, shockable rhythm, adrenaline dose <2 mg, low-flow duration <18 min, reactive pupillary light reflex, Glasgow Coma Scale motor score ≥2, and levels of creatinine <1.21 mg dl−1, potassium <4.4 mEq l−1, phosphate <5.8 mg dl−1, haemoglobin ≥13.2 g dl−1, and lactate <8 mmol l−1 were retained in the final multivariable model and used to develop the scoring system. Our model demonstrated excellent discrimination in the validation set (area under the curve of 0.942, 95% confidence interval 0.917–0.968). ConclusionsWe developed a scoring model for early prognostication in unselected adult cardiac arrest patients. Further validations in various cohorts are needed.

Shortening of low-flow duration over time was associated with improved outcomes of extracorporeal cardiopulmonary resuscitation in in-hospital cardiac arrest

IntroductionQuality improvement in the administration of extracorporeal cardiopulmonary resuscitation (ECPR) over time and its association with low-flow duration (LFD) and outcomes of cardiac arrest (CA) have been insufficiently investigated. In this study, we hypothesized that quality improvement in efforts to shorten the duration of initiating ECPR had decreased LFD over the last 15 years of experience at an academic tertiary care hospital, which in turn improved the outcomes of in-hospital CA (IHCA).MethodsThis was a single-center retrospective observational study of ECPR patients between January 2003 and December 2017. A rapid response system (RRS) and an extracorporeal membrane oxygenation (ECMO) program were initiated in 2011 and 2013. First, the association of LFD per minute with the 90-day mortality and neurological outcome was analyzed using multiple logistic regression analysis. Then, the temporal changes in LFD were investigated.ResultsOf 175 study subjects who received ECPR, 117 had IHCA. In the multivariate logistic regression, IHCA patients with shorter LFD experienced significantly increased 90-day survival and favorable neurological outcomes (LFD per minute, 90-day survival: odds ratio [OR] = 0.97, 95% confidence interval [CI] = 0.94–1.00, P = 0.032; 90-day favorable neurological outcome: OR = 0.97, 95% CI = 0.94–1.00, P = 0.049). In the study period, LFD significantly decreased over time (slope − 5.39 [min/3 years], P < 0.0001).ConclusionA shorter LFD was associated with increased 90-day survival and favorable neurological outcomes of IHCA patients who received ECPR. The quality improvement in administering ECPR over time, including the RRS program and the ECMO program, appeared to ameliorate clinical outcomes.

Influence of hydropower outflow characteristics on riverbank stability: case of the lower Osage River (Missouri, USA)

ABSTRACT This research examined the influences of outflow characteristics affecting riverbank stability. The 130-km stretch of the Lower Osage River downstream from Bagnell Dam (Missouri, USA) provided an excellent case study for this purpose. The integrated BSTEM model with the HEC-RAS model was accurately calibrated and validated with data from the US Geological Survey. Then, the outflow characteristics (peak flow duration, flow drawdown rate, and low flow duration) were investigated individually. The results of this study showed that: (1) riverbank stability is little affected by the duration time of the peak flow, especially on the reaches far from the dam; (2) sudden flow drawdown significantly reduces riverbank stability; however, the impact of the drawdown rate decreases with distance from the dam; and (3) the duration of the low flow after peak flow influences the riverbank stability value proportional to the distance from the dam. The time of low flow before failure increases as the distance from the dam increases.

Prognostic value of transient conduction disturbance in out-of-hospital cardiac arrest.

A retrospective observational study to verify the impact of electrocardiograms (ECGs) following out-of-hospital cardiac arrest (OHCA) on mortality. We retrospectively studied 101 OHCA patients who achieved a return of spontaneous circulation (ROSC) and survived for ≥3h. Among them, 50 patients (66±17years; 22 male) were evaluated using 12-lead ECGs repeatedly and were included in the final analysis: immediately after ROSC (initial ECG) and after the initial evaluation in the emergency department (second ECG). Transient conduction disturbance (transient CD) was defined as a narrowing in QRS duration from the initial to second ECG of ≥18ms. Multivariate Cox regression analyses were carried out to predict 90-day mortality following OHCA. Among 50 OHCA patients, 30 patients survived for 90days. Thirty patients had initial ventricular fibrillation rhythm. Median emergency medical services response time and low-flow duration were 8 and 21min, respectively. Multivariate analysis showed that the transient CD and low-flow duration were significant predictors of all-cause mortality (hazard ratio 16.55, 1.06; P=0.001, 0.022, respectively). Transient CD is a powerful predictor of 90-day mortality in patients who survived 3h after ROSC from OHCA.

Abstract 325: Characteristics and Outcomes of Hanging Induced Out-Of-Hospital Cardiac Arrest: Insights From the Paris Sudden Death Expertise Center Registry

Introduction: Hanging-induced Out-of-Hospital cardiac arrest (OHCA) is poorly studied and a better understanding of these specific OHCA could be helpful to improve patients’ outcome. The main objective of our study was to describe characteristics and outcomes in patients who had OHCA from hanging injuries. Methods: From May 2011 to December 2017 we analyzed a prospectively collected Utstein database for all OHCA adults. All cases due to hanging were included. Utstein style variables were compared for 2 groups of patients: those with a Return of Spontaneous Circulation (ROSC) and those without (non-ROSC). Continuous data are described as means (extremes). Results: Among 25 055 OHCA, 500 patients were included. They were 49 (18-100) years old. Seventy-three (14.6%) hanging were witnessed and 58 (11.6%) benefited from a bystander cardiopulmonary resuscitation before Emergency Medical Service (EMS) arrival. No-flow duration was 29.1 (4-180) minutes. Advance life support was initiated by EMS in 299 (59.8%) cases. Low-flow duration was 23.8 (2-79) minutes. Nine patients (1.8%) had a shockable initial rhythm. We observed 83 (16.6%) ROSC. Four (0.8%) patients were discharged alive from hospital. They were all CPC 1. Table 1 compares characteristics with significant differences between ROSC and non-ROSC groups. Conclusion: As expected, younger age, short no-flow and low-flow durations and shockable rhythm on EMS arrival were significantly associated with ROSC. Overall prognosis is dramatically poor when OHCA is due to hanging (&lt;1%), with a very low proportion of shockable rhythm, even if the rare survivors have an excellent CPC at discharge. Indeed, the best method to reduce the mortality rate of hanging is, with no contest, the prevention of suicidal act.

P6379The impact of coronary artery evaluation and intervention to predict mortality and neurological outcome in out-of-hospital cardiac arrest patients with extra corporeal cardiopulmonary resuscitation

Abstract Background Refractory cardiac arrest (CA), as defined by the absence of a return of spontaneous circulation (ROSC) is associated with poor prognosis. Current guidelines advocate the use of extracorporeal cardiopulmonary resuscitation (ECPR) for selected patients with CA. Although previous studies have reported the association of survival with some prognostic factors such as age, bystander CPR attempt, low-flow duration or lactate serum level, the impact of the evaluation of coronary artery by coronary angiography (CAG) and the revascularization of coronary artery stenosis have not been sufficiently elucidated. Purpose We sought to investigate impact of the CAG and the revascularization of coronary artery stenosis to predict mortality and neurological outcome at 30 days in out-of-hospital CA (OHCA) patients resuscitated by ECPR. Methods 1382 out-of-hospital cardiac arrest patients were transferred to our critical care center, of which 899 patients with refractory CA at the emergency department were extracted from the institutional consecutive database between January 2015 and December 2018. Among those patients, we performed ECPR for 85 patients, who were successfully resuscitated. To predict mortality in hospital and neurological outcome at 30 days, we investigated basic patients' characteristics, pre-hospital information, and post-hospital care including CAG and coronary revascularization. Results Among those who had first resuscitated by ECPR, 20 patients (23.5%) survived and 10 patients (11.8%) achieved good neurological outcome (cerebral-performance-category (CPC) =1 or 2) at 30 days. We performed CAG for 40 patients (47.1%) and revascularization by percutaneous coronary intervention for 25 patients (29.4%). Younger age (P=0.037), CAG (P=0.001), PCI (P=0.001), and hypothermia therapy (P&lt;0.001) were associated with low mortality. In the multivariate analysis, age (Odds ratio (OR) 0.95; 95% confidence interval (CI) 0.91–0.99; P=0.0025), PCI (OR 4.5; 95% CI 1.15–17.6; P=0.031), and hypothermia therapy (OR 13.7; 95% CI 1.52–124; P=0.020) were independent predictors of 30-days survival. Without diabetes mellitus (P=0.024), CAG (P&lt;0.001), PCI (P=0.006), and hypothermia therapy (P=0.038) were associated with good neurological outcome. PCI (OR 7.39; 95% CI 1.73–31.6; P&lt;0.001) was independently predictive for good neurological outcome. Conclusions Successful PCI was an independent predictor of 30-days survival and good neurological outcome in OHCA patients who were resuscitated by ECPR.

Cardiac Arrest Prior to Venoarterial Extracorporeal Membrane Oxygenation: Risk Factors for Mortality

Mortality after cardiac arrest remains high despite initiation of venoarterial extracorporeal membrane oxygenation. We aimed to identify pre-venoarterial extracorporeal membrane oxygenation risk factors of 90-day mortality in patients with witnessed cardiac arrest and with greater than or equal to 1 minute of cardiopulmonary resuscitation before venoarterial extracorporeal membrane oxygenation. The association between preimplant variables and all-cause mortality at 90 days was analyzed with multivariable logistic regression. Retrospective observational cohort study. Tertiary medical center. Seventy-two consecutive patients with cardiac arrest prior to venoarterial extracorporeal membrane oxygenation cannulation. None. Median age was 56 years (interquartile range, 43-56 yr), 75% (n = 54) were men. Out-of-hospital cardiac arrest occurred in 12% (n = 9) of the patients. Initial cardiac rhythm was nonshockable in 57% (n = 41) and shockable in 43% (n = 31) of patients. Median cardiopulmonary resuscitation duration was 21 minutes (interquartile range, 10-73 min; range, 1-197 min]. No return of spontaneous circulation was present in 64% (n = 46) and postarrest cardiogenic shock in 36% (n = 26) of the patients at venoarterial extracorporeal membrane oxygenation cannulation. Median duration of venoarterial extracorporeal membrane oxygenation was 5 days (interquartile range, 2-12 d). The 90-day overall mortality and in-hospital mortality were 57% (n = 41), 53% (n = 38) died during venoarterial extracorporeal membrane oxygenation, and 43% (n = 31) were successfully weaned. All survivors had Cerebral Performance Category score 1-2 at discharge to home. Multivariable logistic regression analysis identified initial nonshockable cardiac arrest rhythm (odds ratio, 12.2; 95% CI, 2.83-52.7; p = 0.001), arterial lactate (odds ratio per unit, 1.15; 95% CI, 1.01-1.31; p = 0.041), and ischemic heart disease (7.39; 95% CI, 1.57-34.7; p = 0.011) as independent risk factors of 90-day mortality, whereas low-flow duration, return of spontaneous circulation, and age were not. In 72 patients with cardiac arrest before venoarterial extracorporeal membrane oxygenation initiation, nonshockable rhythm, arterial lactate, and ischemic heart disease were identified as independent pre-venoarterial extracorporeal membrane oxygenation risk factors of 90-day mortality. The novelty of this study is that the metabolic state, expressed as level of lactate just before venoarterial extracorporeal membrane oxygenation initiation seems more predictive of outcome than cardiopulmonary resuscitation duration or absence of return of spontaneous circulation.

An urgent open surgical approach for left ventricle venting during peripheral veno-arterial extracorporeal membrane oxygenation for refractory cardiac arrest: case report

The objective of the study is to describe an emergency procedure for left ventricle venting during veno-arterial extracorporeal life support for refractory cardiac arrest. Veno-arterial extracorporeal membrane oxygenation is widely used in refractory cardiac arrest but is characterized by an increase in left ventricle afterload, which may impair cardiac contractility improvement. Different left ventricle venting techniques are available. We report the use of a surgical approach with sternotomy for left ventricle venting in a 21-year-old patient who was placed under veno-arterial extracorporeal membrane oxygenation for refractory cardiac arrest with severe pulmonary edema, respiratory failure, and left ventricle stasis. A 21-year-old woman was admitted for laparoscopic sleeve gastrectomy. In the recovery room, she developed a refractory circulatory shock. Transthoracic echocardiography revealed a dilated cardiomyopathy with severe left ventricle systolic dysfunction (left ventricle ejection fraction at 20%). Coronary angiogram was normal. On day 2, she underwent laparotomy for sepsis and she presented cardiac arrest secondary to ventricular tachycardia. We proceeded to peripheral veno-arterial extracorporeal membrane oxygenation as the cardiac arrest was refractory. A miniaturized veno-arterial extracorporeal membrane oxygenation system was implanted into the right femoral vessels onsite .The low flow duration was 40 minutes. Veno-arterial extracorporeal membrane oxygenation blood flow was set to 3 L min-1, resulting in a closed aortic valve and a massive pulmonary edema. Transesophageal echocardiography showed left ventricular ejection fraction at 5% without aortic valve opening. We first implanted an intra-aortic balloon pump without clinical improvement. Transesophageal echocardiography revealed massive thrombus formation into the aortic root. We decided to perform an open surgical approach for left ventricle unload using a transmitral cannula (22 Fr) via the right superior pulmonary vein connected to the inflow tube of the veno-arterial extracorporeal membrane oxygenation with Y connection. Transesophageal echocardiography showed a full opening of aortic valve and elimination of valve aortic thrombus. Chest radiography showed a significant decrease of pulmonary congestion. We were able to withdraw extracorporeal life support organization on day 10 and discharged on day 54. Clinical explorations reveal a fulminant rocuronium-related hypersensitivity myocarditis. This salvage surgical technique using a modified central veno-arterial extracorporeal membrane oxygenation cannulation technique has efficiently decreased blood stasis and permitted rapid recovery.

Exploring parsimonious daily rainfall-runoff model structure using the hyperbolic tangent function and Tank model

Mathematical models with small numbers of parameters are useful for hydrological analyses and water resources planning as they are easier to prepare, use, and interpret compared to more complex models. Many simple model structures and simulation strategies have been developed, but there is still substantial room for improvement in the efficiency of daily rainfall-runoff modeling. This study proposes daily rainfall-runoff models that require only two to four parameters yet are capable of predicting peak discharge and baseflow. Parsimonious model structures were obtained using the hyperbolic tangent function and combining it with one subsurface layer and two parameters of a Tank model. The daily rainfall-runoff models proposed based on the Two-Parameter Hyperbolic Model (TPHM) and Tank model were applied to 41 watersheds throughout South Korea. Model accuracy was evaluated by comparing observed and simulated watershed streamflow and compared with that of a nine-parameter Tank model. The original TPHM and its variants yielded slightly better efficiency with a smaller number of parameters than the Tank model when reproducing high flows on a daily basis. The accuracy of low flow and flow duration curve predictions provided by the TPHM-based models was higher in watersheds with relatively large baseflow temporal variability. The results suggested that the TPHM-based structures be alternative parsimonious daily rainfall-runoff simulation models. This study demonstrates that daily high streamflow can be efficiently simulated using a two-parameter hydrological model, and daily baseflow simulation can be improved by adding two additional parameters to the model.

Contrasting Differences in Responses of Streamflow Regimes between Reforestation and Fruit Tree Planting in a Subtropical Watershed of China

Fruit tree planting is a common practice for alleviating poverty and restoring degraded environment in developing countries. Yet, its environmental effects are rarely assessed. The Jiujushui watershed (261.4 km2), located in the subtropical Jiangxi Province of China, was selected to assess responses of several flow regime components on both reforestation and fruit tree planting. Three periods of forest changes, including a reference (1961 to 1985), reforestation (1986 to 2000) and fruit tree planting (2001 to 2016) were identified for assessment. Results suggest that the reforestation significantly decreased the average magnitude of high flow by 8.78%, and shortened high flow duration by 2.2 days compared with the reference. In contrast, fruit tree planting significantly increased the average magnitude of high flow by 27.43%. For low flows, reforestation significantly increased the average magnitude by 46.38%, and shortened low flow duration by 8.8 days, while the fruit tree planting had no significant impact on any flow regime components of low flows. We conclude that reforestation had positive impacts on high and low flows, while to our surprise, fruit tree planting had negative effects on high flows, suggesting that large areas of fruit tree planting may potentially become an important driver for some negative hydrological effects in our study area.

Long‐term streamflow trends in Hawai'i and implications for native stream fauna

AbstractClimate change has fundamentally altered the water cycle in tropical islands, which is a critical driver of freshwater ecosystems. To examine how changes in streamflow regime have impacted habitat quality for native migratory aquatic species, we present a 50‐year (1967–2016) analysis of hydrologic records in 23 unregulated streams across the five largest Hawaiian Islands. For each stream, flow was separated into direct run‐off and baseflow and high‐ and low‐flow statistics (i.e., Q10 and Q90) with ecologically important hydrologic indices (e.g., frequency of flooding and low flow duration) derived. Using Mann–Kendall tests with a running trend analysis, we determined the persistence of streamflow trends through time. We analysed native stream fauna from ~400 sites, sampled from 1992 to 2007, to assess species richness among islands and streams. Declines in streamflow metrics indicated a general drying across the islands. In particular, significant declines in low flow conditions (baseflows), were experienced in 57% of streams, compared with a significant decline in storm flow conditions for 22% of streams. The running trend analysis indicated that many of the significant downward trends were not persistent through time but were only significant if recent decades (1987–2016) were included, with an average decline in baseflow and run‐off of 10.90% and 8.28% per decade, respectively. Streams that supported higher native species diversity were associated with moderate discharge and baseflow index, short duration of low flows, and negligible downward trends in flow. A significant decline in dry season flows (May–October) has led to an increase in the number of no‐flow days in drier areas, indicating that more streams may become intermittent, which has important implications for mauka to makai (mountain to ocean) hydrological connectivity and management of Hawai'i's native migratory freshwater fauna.

Effect of interplay between age and low-flow duration on neurologic outcomes of extracorporeal cardiopulmonary resuscitation

PurposeCaseloads of extracorporeal cardiopulmonary resuscitation (ECPR) have increased considerably, and hospital mortality rates remain high and unpredictable. The present study evaluated the effects of the interplay between age and prolonged low-flow duration (LFD) on hospital survival rates in elderly patients to identify subgroups that can benefit from ECPR.MethodsAdult patients who received ECPR in our institution (2006–2016) were classified into groups 1, 2, and 3 (18–65, 65–75, and > 75 years, respectively). Data regarding ECPR and adverse events during hospitalization were collected prospectively. The primary end point was favorable neurologic outcome (cerebral performance category 1 or 2) at hospital discharge.ResultsIn total, 482 patients were divided into groups 1, 2, and 3 (70.5%, 19.3%, and 10.2%, respectively). LFDs were comparable among the groups (40.3, 41.0, and 44.3 min in groups 1, 2, and 3, P = 0.781, 0.231, and 0.382, respectively). Favorable neurologic outcome rates were nonsignificantly lower in group 3 than in the other groups (27.6%, 24.7%, and 18.4% for group 1, 2, and 3, respectively). Subgroup analysis revealed that the favorable neurologic outcome rates in group 1 were 36.7%, 25.4%, and 13.0% for LFDs of < 30, 30–60, and > 60 min, respectively (P = 0.005); in group 2, they were 32.1%, 21.2%, and 23.1%, respectively (P = 0.548); in group 3 they were 25.0%, 20.8%, and 0.0%, respectively (P = 0.274).ConclusionOn emergency consultation for ECPR, age and low-flow duration should be considered together to predict neurologic outcome.

Abstract 362: Early Signs of Life as a Prognostic Factor for Extracorporeal Cardiopulmonary Resuscitation in Refractory Out-of-Hospital Cardiac Arrest

Introduction: After 20 to 30 minutes of cardiopulmonary resuscitation (CPR) without return of spontaneous circulation (ROSC), cardiac arrest is considered as refractory (RCA). For RCA, extracorporeal CPR (ECPR) is one of the only treatments with a potential benefit on survival. Presence of gasping during CPR has been shown to be strongly associated with a favorable outcome. To our knowledge, signs of life during CPR (such as gasping, movements, pupillary response) has not been studied in the specific context of RCA treated with ECPR. Hypothesis: We assessed the relationship between survival with favorable neurologic outcomes and presence of early signs of life during or before CPR in RCA treated with ECPR. Methods: We carried out a multicenter observational study of patients with out-of-hospital RCA treated with ECPR in 3 cities in France. Primary outcome was favorable neurologic outcome at 30 days defined as CPC score ≤ 2. Signs of life were defined as gasping or recovery of normal breathing, any pupillary response or any movements during CPR. Patient selection for ECPR was decided according to french guidelines criteria such as initial rhythm, no-flow duration, expected transport time and EtCO2 &gt; 10 mmHg. A logistic regression analysis was performed. P -values &lt; 0.05 were considered statistically significant. Results: Overall, 437 patients treated with ECPR were included with 71 (16%) patients with CPC ≤ 2 at 30 days. Signs of life were observed in 261 (59%) patients, with 136 (31%) patients presenting gasping or respiratory movement, 155 (35%) a pupillary response, and 49 (11%) movements during CPR. Overall 63/261 (24.1%) patients with signs life survived with favorable neurologic outcome vs. 8/176 (4.5%) without signs of life, p&lt;0.0001. In multivariate analysis, factors associated with favorable outcome were: signs of life during CPR (OR 11.0, 95%CI 3.7-32.5; p&lt;0.001), first recorded rhythm VF/VT (OR 3.4, 95%CI 1.3-8.9; P=0.011), low-flow duration per min (OR 0.99, 95%CI 0.98-1.00; p=0.032). Conclusions: These results highlight the importance of signs of life before or during CPR on neurological outcomes for RCA treated with ECPR. These results could help select patients with good chance of survival in whom we should not give up resuscitation efforts too soon.

High-power, low-flow, short-ablation duration-the key to avoid collateral injury?

A common approach to ablating along the posterior wall of the left atrium in atrial fibrillation ablation is to use low power with longer duration for durable lesions and reducing thermal injury. We hypothesize that similar lesions can be safely obtained at high power with low open-irrigation flow and low duration. Twenty-two porcine ventricles were placed in a tissue bath with circulating 0.45% NaCl at a maintained temperature of 37°C. Bipolar radiofrequency ablation (RFA) with a 4-mm-tip irrigated, force-sensing catheter was performed with various combinations of irrigation, power, and duration at 20g of contact force. Fiber optic temperature probes were placed at depths of 3mm and 5mm. Temperature was measured during and 30s after each ablation. Two hundred sixty-eight lesions were made. At a fixed power and flow rate, lesion surface diameter, maximum lesion width, and lesion depth all increased with longer ablation duration. At fixed duration and irrigation flow rate, increased power led to increased lesion dimensions. At a lower flow rate (2ml/min), surface lesion diameter and maximum width were significantly larger compared to a higher flow rate (17ml/min), but lesion depth was not significantly different. The maximum temperature and the rate of temperature rise at a depth of 5mm with different power settings and ablation durations were lower as compared to a depth of 3mm at both flow rates (2ml/min and 17ml/min). Effective lesions can be performed with high-power and short-ablation durations, thereby reducing RFA procedure time. Higher power, shorter duration lesions result in adequate temperature for myocardial lesion formation at 3mm, but do not result in excessive temperature at 5mm depth, potentially reducing the risk of collateral injury. Compared to higher irrigation flow rate, larger surface lesions and comparable maximum lesion width are achieved with lower irrigation flow rate, thus resulting in better lesion contiguity.

Extracorporeal Life Support for Refractory Cardiac Arrest: A 10-Year Comparative Analysis

Cardiopulmonary resuscitation of cardiac arrest has poor outcomes. Extracorporeal life support (ECLS) could represent a salvage option. This study aimed to analyze the outcomes of ECLS used for refractory cardiac arrest. In this observational analysis, patients were divided into an in-hospital cardiac arrest group (IHCA) and an out-of-hospital (OHCA) cardiac arrest group. The primary end point was survival to hospital discharge with good neurologic outcome. Both groups were compared after propensity score matching. Risk factors were searched with multivariate analyses. From January 2007 to December 2016, study investigators performed 131 ECLS procedures (IHCA, n= 45, 34.4%; OHCA, n= 86, 65.6%). The mean age of patients was 43.2 years, and 71.8% were male. Baseline characteristics were comparable between both groups except mean no-flow duration (0.2 minutes vs 2.5 minutes; p < 0.001) and low-flow duration (46.9 minutes vs 85.3 minutes; p < 0.001), which were significantly shorter in the IHCA group. A total of 103 (82.4%) patients died during ECLS (IHCA, 79.1% vs OHCA, 84.1%; p= 0.479). The complication rate during ECLS was comparable between both groups. Twenty (16%) patients were successfully weaned from ECLS (IHCA, 18.6% vs OHCA, 14.6%; p= 0.565) after a mean support period of 6.7 days. Survival to hospital discharge with good neurologic outcome was not different between the two matched groups (odds ratioOHCA vs IHCA 1.3; 95% confidence interval, 0.023 to 74.902; p= 0.9). Presence of shockable rhythm was associated with a better outcome (odds ratioshockable vs nonshockable 6.674; 95% confidence interval, 1.078 to 41.336; p= 0.044). Patients in the IHCA and OHCA groups experienced the same survival with good neurologic outcome after ECLS support. A better selection of patients with IHCA is mandatory to avoid futile support.

Combination of hemoglobin and low-flow duration can predict neurological outcome in the initial phase of out-of-hospital cardiac arrest

PurposeTo predict neurological outcome following out-of-hospital cardiac arrest (OHCA) using a combination of hemoglobin (Hb) and low-flow duration (LFD). Materials and methodsWe retrospectively examined 131 patients (75 ± 13 years, 64 men) with return of spontaneous circulation (ROSC) following non-traumatic OHCA. The LFD was the duration from the start of cardiopulmonary resuscitation to ROSC. To obtain the Hb/LFD value, we divided the Hb level by the LFD. Multivariate logistic regression analyses were performed to predict full neurological recovery (FNR), defined as Cerebral Performance Category scale scores of 1 or 2 at discharge. ResultsNineteen patients (15%) achieved FNR. Patients with FNR had high Hb levels (14.9 ± 2.1 vs. 11.3 ± 2.7 g/dl, p = 0.001) and short LFDs (10 [5, 18] vs. 35 [28, 43] min, p = 0.001). Multivariate analyses identified the initial ventricular fibrillation rhythm and Hb/LFD as significant predictors for FNR (odds ratio: 24.9, 3.58; p = 0.001, 0.02, respectively). Receiver operating characteristic (ROC) curve analyses indicated that a high Hb/LFD predicted FNR (cut-off value: 0.50, sensitivity: 94.7%, specificity: 84.5%, area under the curve: 0.933). ConclusionsPatients with FNR following OHCA had high Hb levels and short LFDs; the Hb/LFD value significantly predicted FNR.