Influence of body mass index on the prognosis of patients successfully resuscitated from out-of-hospital cardiac arrest treated by therapeutic hypothermia

Association between body mass index and clinical outcomes in patients with out-of-hospital cardiac arrest undergoing extracorporeal cardiopulmonary resuscitation: A multicenter observational study

Background

We examined the association between body mass index (BMI) and outcomes in patients with out-of-hospital cardiac arrest (OHCA) undergoing extracorporeal cardiopulmonary resuscitation (ECPR).

Methods

We retrospectively analyzed the database of an observational multicenter cohort in Japan. Adult patients with OHCA of cardiac etiology who received ECPR between 2013 and 2018 were categorized as follows: underweight, BMI < 18.5; normal weight, BMI = 18.5-24.9; overweight, BMI = 25-29.9; and obese, BMI ≥ 30 kg/m2. The primary outcome was in-hospital mortality; secondary outcomes were unfavorable neurological outcomes at discharge (cerebral performance category ≥ 3) and ECPR-related complications. BMI's association with outcomes was assessed using a logistic regression model adjusted for age, sex, comorbidities, witness/bystander CPR, initial rhythm, prehospital return of spontaneous circulation, and low-flow time.

Results

In total, 1,044 patients were analyzed. Their median age was 61 (IQR, 49-69) years; the median BMI was 24.2 (21.5-26.9) kg/m2. The overall rates of in-hospital mortality, unfavorable neurological outcome, and ECPR-related complications were 62.2%, 79.9%, and 31.7%, respectively. In multivariate analysis, the overweight and obese groups had higher in-hospital mortality odds than the normal BMI group (odds ratio [95%CI], 1.37 [1.02-1.85], p = 0.035; and 2.09 [1.31-3.39], p < 0.001, respectively). The odds ratio for unfavorable neurological outcomes increased more in the obese than in the normal BMI group (3.17 [1.69-6.49], p < 0.001). ECPR-related complications were not significantly different among groups.

Conclusions

In OHCA patients undergoing ECPR, a BMI ≥ 25 kg/m2 was associated with increased in-hospital mortality, and a BMI ≥ 30 kg/m2 was also associated with a worse neurological outcome.

Impact of Body Mass Index on Cardiac Arrest Outcomes: A Systematic Review and Meta-Analysis

The influence of an individual's body mass index (BMI) on cardiac arrest outcomes remains uncertain. The aim of this study is to evaluate the impact of BMI categories (underweight, normal BMI, overweight, and obese) on mortality and neurological outcomes in patients experiencing cardiac arrest. We comprehensively searched standard electronic databases (PubMed, EMBASE, and Scopus) for relevant observational studies published in peer-reviewed journals written in English. We calculated pooled effect estimates using random-effects models and reported them as odds ratios (ORs) with 95% confidence intervals (CIs). We included 20 studies in our meta-analysis. Individuals with normal BMIs and those who were underweight had similar risks of in-hospital mortality (OR, 1.20; 95% CI, 0.90-1.60), mortality within 6 months of discharge (OR, 0.92; 95% CI, 0.59-1.42), mortality after the 1-year follow-up (OR, 2.42; 95% CI, 0.96-6.08), and odds of favorable neurological outcomes at hospital discharge (OR, 0.86; 95% CI, 0.53-1.39) and at the 6-month follow-up (OR, 0.73; 95% CI, 0.47-1.13). The risks of in-hospital mortality and mortality within 6 months of discharge in overweight and obese individuals were similar to those in individuals with normal BMIs. However, overweight (OR, 0.57; 95% CI, 0.35-0.92) and obese individuals (OR, 0.67; 95% CI, 0.51-0.89) had lower risks of mortality after their 1-year follow-ups. For overweight and obese subjects, the reduced risk of mortality after the 1 year of follow-up was noted only for those with in-hospital cardiac arrest and not for those with out-of-hospital cardiac arrest. The odds of favorable neurological outcomes in both overweight and obese individuals were similar to those with normal BMIs. BMI does not significantly impact short-term mortality or neurological outcomes. Overweight and obese individuals appear to have a lower risk of long-term mortality, but this differed by the place of arrest and needs to be confirmed by others.

The Impact Of BMI On Arrest Characteristics and Survival of Patients with Out-Of-Hospital Cardiac Arrest Treated With Extracorporeal Cardiopulmonary Resuscitation

AIM

To assess the impact of body mass index (BMI) on survival to hospital discharge of patients presenting with refractory ventricular fibrillation treated with extracorporeal cardiopulmonary resuscitation. We hypothesize that due to limitations in pre-hospital care delivery, people with high BMI have worse survival after prolonged resuscitation and ECPR.

METHODS

This study is a retrospective single-centre study that included patients suffering refractory VT/VF OHCA from December 2015 to October 2021 and had a BMI calculated at hospital admission. We compared the baseline characteristics and survival between patients with obesity (>30 kg/m²) and those without (≤30kg/m²).

RESULTS

Two-hundred eighty-three patients were included in this study, and two-hundred twenty-four required mechanical support with veno-arterial extracorporeal cardiopulmonary membrane oxygenation (VA ECMO). Patients with BMI >30 (n = 133) had significantly prolonged CPR duration compared to their peers with BMI ≤30kg/m² (n = 150) and were significantly more likely to require support with VA ECMO (85.7% vs 73.3%, p = 0.015). Survival to hospital discharge was significantly higher in patients with BMI≤30 kg/m² (48% vs. 29.3%, p <0.001). BMI was an independent predictor of mortality in a multivariable logistic regression analysis. The four-year mortality rate was low and not significantly different between the two groups (p=0.32).

CONCLUSION

ECPR yields clinically meaningful long-term survival in patients with BMI>30kg/m². However, the resuscitation time is significantly prolonged, and the overall survival significantly lower compared to patients with BMI≤30 kg/m². ECPR should, therefore, not be withheld for this population, but faster transport to an ECMO capable centre is mandated to improve survival to hospital discharge.

Lower limb muscle matters in patients with hypoxic brain injury following out-of-hospital cardiac arrest

BACKGROUND

There are conflicting results regarding the association between body mass index and the prognosis of cardiac arrest patients. We investigated the association of the composition and distribution of muscle and fat with neurologic outcomes at hospital discharge in successfully resuscitated out-of-hospital cardiac arrest (OHCA) patients.

METHODS

This prospective, single-centre, observational study involved adult OHCA patients, conducted between April 2019 and June 2021. The ratio of total skeletal muscle, upper limb muscle, lower limb muscle, and total fat to body weight was measured using InBody S10, a bioimpedance analyser, after achieving the return of spontaneous circulation. Restricted cubic spline curves with four knots were used to examine the relationship between total skeletal muscle, upper limb muscle, and lower limb muscle relative to total body weight and neurologic outcome at discharge. Multivariable logistic regression analysis was performed to assess an independent association.

RESULTS

A total of 66 patients were enrolled in the study. The proportion of total muscle and lower limb muscle positively correlated with the possibility of having a good neurologic outcome. The proportion of lower limb muscle showed an independent association in the multivariable analysis (adjusted odds ratio, 2.29; 95% confidence interval, 1.06-13.98), and its optimal cut-off value calculated through receiver operating characteristic curve analysis was 23.1%, which can predict a good neurological outcome.

CONCLUSIONS

A higher proportion of lower limb muscle to body weight was independently associated with the probability of having a good neurologic outcome in OHCA patients.

Obesity in young sudden cardiac death: Rates, clinical features, and insights into people with body mass index >50kg/m2

•

55.0% of young sudden cardiac death (SCD) patients in Victoria, Australia are obese.

•

This obesity prevalence exceeds that in the age-matched general Australian population, with all classes of obesity over-represented in our SCD cohort.

•

Patients with BMI>50 kg/m² represented 8.5% of young SCD. Almost two thirds of patients with BMI>50 kg/m² died from left ventricular hypertrophy, with fewer than 10% dying from coronary disease.

Objective

To contextualize obesity rates in young sudden cardiac death (SCD) against the age-matched national population, and identify clinical and pathologic features in WHO class II and III obesity.

Methods

A prospective state-wide out-of-hospital cardiac arrest registry included all SCDs in Victoria, Australia from 2019–2021. Body mass indices (BMIs) of patients 18-50 years were compared to age-referenced general population. Characteristics of SCD patients with WHO Class II obesity (BMI ≥30kg/m²) and non-obesity (BMI<30kg/m²) were compared. Clinical characteristics of people with BMI>50kg/m² were assessed.

Results

504 patients were included. Obesity was strongly over-represented in young SCD compared to the age-matched general population (55.0% vs 28.7%, p<0.0001). Obese SCD patients more frequently had hypertension, diabetes and obstructive sleep apnoea (p<0.0001, p=0.009 and p=0.001 respectively), ventricular fibrillation as their arrest rhythm (p=0.008) and left ventricular hypertrophy (LVH) (p<0.0001). Obese patients were less likely to have toxicology positive for illicit substances (22.0% vs 32.6%, p=0.008) or history of alcohol abuse (18.8% vs 26.9%, p=0.030). Patients with BMI>50 kg/m² represented 8.5% of young SCD. LVH (n=26, 60.5%) was their predominant cause of death and only 10 (9.3%) patients died from coronary disease.

Conclusion

Over half of young Australian SCD patients are obese, with all obesity classes over-represented compared to the general population. Obese patients had more cardiac risk factors. Almost two thirds of patients with BMI>50 kg/m² died from LVH, with fewer than 10% dying from coronary disease.

The relationship between body mass index and neurologic outcomes in survivors of out-of-hospital cardiac arrest treated with targeted temperature management

Background

The association of body mass index with outcome in patients treated with targeted temperature management (TTM) after out-of-hospital cardiac arrest (OHCA) is unclear. The purpose of this study was to examine the effect of body mass index (BMI) on neurological outcomes and mortality in resuscitated patients treated with TTM after OHCA.

Methods

This multicenter, prospective, observational study was performed with data from 22 hospitals included in the Korean Hypothermia Network KORHN-PRO registry. Comatose adult patients treated with TTM after OHCA between October 2015 and December 2018 were enrolled. The BMI of each patient was calculated and classified according to the criteria of the World Health Organization (WHO). Each group was analyzed in terms of demographic characteristics and associations with six-month neurologic outcomes and mortality after cardiac arrest (CA).

Results

Of 1,373 patients treated with TTM identified in the registry, 1,315 were included in this study. One hundred two patients were underweight (BMI <18.5 kg/m²), 798 were normal weight (BMI 18.5–24.9 kg/m²), 332 were overweight (BMI 25–29.9 kg/m²), and 73 were obese (BMI ≥ 30 kg/m²). The higher BMI group had younger patients and a greater incidence of diabetes and hypertension. Six-month neurologic outcomes and mortality were not different among the BMI groups (p = 0.111, p = 0.234). Univariate and multivariate analyses showed that BMI classification was not associated with six-month neurologic outcomes or mortality. In the subgroup analysis, the underweight group treated with TTM at 33°C was associated with poor neurologic outcomes six months after CA (OR 2.090, 95% CI 1.010–4.325, p = 0.047), whereas the TTM at 36°C group was not (OR 0.88, 95% CI 0.249–3.112, p = 0.843).

Conclusions

BMI was not associated with six-month neurologic outcomes or mortality in patients surviving OHCA. However, in the subgroup analysis, underweight patients were associated with poor neurologic outcomes when treated with TTM at 33°C.

The impact of obesity on outcomes of patients admitted to intensive care after cardiac arrest

PURPOSE

Studies examining the association between obesity and mortality in cardiac arrest patients have been conflicting which might either be due to residual confounding, or a reliance on estimating the conditional effects rather than the marginal (causal) effects of obesity. We estimated the conditional and causal effects of obesity on mortality in cardiac arrest patients using the Australian and New Zealand Intensive Care Society (ANZICS) Adult Patient Database (APD).

MATERIALS AND METHODS

This retrospective registry-based cohort study from ICUs of Australia and New Zealand included all ICU patients admitted with cardiac arrest between 2010 and 2020 with height and weight data recorded. The conditional and marginal effects of obesity on mortality was estimated using multivariate binary logistic regression and Targeted Maximum Likelihood Estimation (TMLE) respectively. The primary outcome was in-hospital mortality.

RESULTS

A total 13,970 patients had complete data and were available for analysis. In multivariate binary logistic regression, there was no difference in the odds of in-hospital mortality for the obese versus non-obese groups; adjusted OR = 0.95, 95% CI = 0.87-1.03; p 0.25. Results were similar using TMLE (Marginal OR= 0.97; 95% CI = 0.91-1.02, p = 0.62).

CONCLUSION

After adjustment, there was no association between obesity and outcomes in cardiac arrest patients admitted to ICU.

The Impact of Obesity on Sudden Cardiac Death Risk

PURPOSE OF REVIEW

We aimed to describe the epidemiology of sudden cardiac death (SCD) in the obese, elaborating on the potential pathophysiological mechanisms linking obesity, SCD, and the outcomes in SCD survivors, as well as looking into the intriguing "obesity paradox" in these patients.

RECENT FINDINGS

Several studies show increased mortality in patients with BMI > 30 kg/m² admitted to the hospital following SCD. At the same time, other studies have implied that the "obesity paradox," described in various cardiovascular conditions, applies to patients admitted after SCD, showing lower mortality in the obese compared to normal weight and underweight patients. We found a significant body of evidence to support that while obesity increases the risk for SCD, the outcomes of obese patients post SCD are better. These findings should not be interpreted as supporting weight gain, as it is always better to prevent the "disaster" from happening than to improve your chances of surviving it. Obesity is shown to be significantly associated with increased risk for SCD; however, there is a growing body of evidence, supporting the "obesity paradox" in the survival of SCD victims. Prospectively, well-designed studies are needed to confirm these findings.

Does the use of BariBoard™ improve adequacy of chest compressions in morbid obesity? A pilot study using a simulation model

BACKGROUND

Obesity is a growing health problem worldwide. Morbid obesity has been associated with significant barriers to effective thoracic cage compression during cardiopulmonary resuscitation.

OBJECTIVE

The BariBoard™ purports to improve adequacy of chest compressions in morbidly obese patients. This study uses a simulation model to evaluate this.

METHODS

This was a prospective blinded randomised-controlled crossover pilot trial using a simulation model of obesity. Participants, recruited from hospital departments and prehospital services, performed 2 minutes of continuous compressions on mannequins modified to emulate a morbidly obese patient. Participants were randomised by coin toss to a sequence of either control/intervention or intervention/control, with the BariBoard™ in the intervention arm. Accelerometers measured chest wall movement during compressions. The primary endpoint was a composite measure of compression adequacy (rate, depth, and recoil). Secondary endpoints comprised the individual components of the composite outcome, as both dichotomous outcomes (adequate vs. inadequate) and continuous variables. All endpoints were adjusted for potential confounders.

RESULTS

Of 205 participants recruited, 201 were analysed. There was a significant difference in the primary outcome between the control and intervention arms (13.4% vs. 4.5%, respectively, p = 0.001) and between the control and intervention arms for the secondary endpoints of adequate compression depth (31.3% vs. 15.9%, p < 0.001) and recoil (63.7% vs. 41.3%, p < 0.001). After adjustment for confounders and interactions, there was no difference in overall efficacy (odds ratio: 0.62, 95% confidence interval: 0.20-1.90, p = 0.40).

CONCLUSION

This pilot study describes the successful assessment of a device using a simulation model of obesity. Within these constraints and after adjustment for confounders, use of the BariBoard ™ did not improve efficacy of chest compressions.

Emergencies in obese patients: a narrative review

Obesity is associated to an increased risk of morbidity and mortality due to respiratory, cardiovascular, metabolic, and neoplastic diseases. The aim of this narrative review is to assess the physio-pathological characteristics of obese patients and how they influence the clinical approach during different emergency settings, including cardiopulmonary resuscitation. A literature search for published manuscripts regarding emergency and obesity across MEDLINE, EMBASE, and Cochrane Central was performed including records till January 1, 2021. Increasing incidence of obesity causes growth in emergency maneuvers dealing with airway management, vascular accesses, and drug treatment due to both pharmacokinetic and pharmacodynamic alterations. Furthermore, instrumental diagnostics and in/out-hospital transport may represent further pitfalls. Therefore, people with severe obesity may be seriously disadvantaged in emergency health care settings, and this condition is enhanced during the COVID-19 pandemic, when obesity was stated as one of the most frequent comorbidity. Emergency in critical obese patients turns out to be an intellectual, procedural, and technical challenge. Organization and anticipation based on the understanding of the physiopathology related to obesity are very important for the physician to be mentally and physically ready to face the associated issues.

Predictors of poor outcome after extra-corporeal membrane oxygenation for refractory cardiac arrest (ECPR): A post hoc analysis of a multicenter database

BACKGROUND

The objective was to assess predictors for unfavorable neurological outcome (UO) in out-of-hospital (OHCA) and in-hospital (IHCA) cardiac arrest patients treated with Extracorporeal cardiopulmonary resuscitation (ECPR).

METHODS

A post hoc analysis of retrospective data from five European ECPR centers (January 2012-December 2016) was performed. The primary composite endpoint was 3-month UO defined as survival with a cerebral performance category (CPC) of 3-4 or death (CPC 5).

RESULTS

A total of 413 patients treated with ECPR were included (median age was 57 [48-65] years, male gender 78%): 61% of patients (n = 250) suffered OHCA. The median time from collapse to ECMO placement was 63 [45-82] minutes. Overall, 81% patients (n = 333) showed unfavorable UO, which was higher in OHCA patients (90% vs 66%), as compared to IHCA. In OHCA, prolonged time from collapse to ECMO initiation (OR 1.02, p < 0.01) and higher ECMO blood flow (OR 1.99, p = 0.01) were associated with UO while initial shockable rhythm (OR 0.04, p < 0.01), previous heart disease (OR 0.20, p < 0.01) and pre-hospital hypothermia (OR 0.08, p < 0.01) had a protective role. In IHCA, prolonged time from arrest to ECMO implantation (OR 1.02, p = 0.03), high lactate level on admission (OR 1.15, p < 0.01) and higher body weight (OR 1.03, p < 0.01) were independently associated with UO.

CONCLUSIONS

IHCA and OHCA patients receiving ECPR have different predictors of UO at presentation, suggesting that selection criteria for ECPR should be decided according to the location of CA. After ECMO initiation, ECMO blood flow management and mean arterial pressure targets might also impact neurological recovery.

The relationship between the body mass index and in-hospital mortality in patients admitted for sudden cardiac death in the United States

While obesity has been shown to be associated with elevated risk for Sudden Cardiac Death (SCD), studies examining its effect on outcomes in SCD victims have shown conflicting results. We aimed to describe the body mass index (BMI) distribution in a nationwide cohort of patients admitted for an out of hospital SCD (OHSCD), and the relationship between BMI and in‐hospital mortality. We drew data from the U.S. National Inpatient Sample (NIS), to identify cases of OHSCD. Patients were divided into six groups based on their BMI (underweight, normal weight, overweight, obese I, obese II, extremely obese). Socio‐demographic and clinical data were collected, mortality and length of stay were analyzed. Multivariate analysis was performed to identify predictors of mortality. Among a weighted total of 2330 hospitalizations for OHSCD in patients with documented BMI, the mean age was 62.3 ± 29 years, 52.4% were male and 62% were white. The overall rate of in‐hospital mortality was 69.3%. A U‐shaped relationship between the BMI and mortality was documented, as patients with 25 < BMI < 40 exhibited significantly lower mortality (60.7%) compared to the other BMI groups (75.2%), p < .001. BMI of 25 kg/m² and below or 40 kg/m² and above, were independent predictors of in‐hospital mortality in a multivariate analysis along with prior history of congestive heart failure and Deyo Comorbidity Index of ≥2. A U‐shaped relationship between the BMI and in‐hospital mortality was documented in patients hospitalized for an out of hospital sudden cardiac death in the United States in the recent years.

Association between Body Mass Index and Outcomes in Patients with Return of Spontaneous Circulation after Out-of-Hospital Cardiac Arrest: A Systematic Review and Meta-Analysis

Increased body mass index (BMI) is a risk factor for cardiovascular disease, stroke, and metabolic diseases. A high BMI may affect outcomes of post-cardiac arrest patients, but the association remains debatable. We aimed to determine the association between BMI and outcomes in patients with return of spontaneous circulation (ROSC) after out-of-hospital cardiac arrest (OHCA). A systematic literature search was conducted using MEDLINE, EMBASE, and the Cochrane Library. Studies that included patients who presented ROSC after OHCA, had a recorded BMI, and were assessed for neurological outcomes and in-hospital mortality were included. To assess the risk of bias of each included study, we employed the Risk of Bias Assessment Tool for Non-randomized Studies. We assessed 2427 patients from six studies. Neurological outcomes were significantly poorer in underweight patients (risk ratio (RR) = 1.21; 95% confidence interval (CI) = 1.07-1.37; p = 0.002; I2 = 51%) than in normal-weight patients. Additionally, in-hospital mortality rate was significantly higher in underweight patients (RR = 1.35; 95% CI = 1.14-1.60; p<0.001; I2 = 21%) and in obese patients (RR = 1.25; 95% CI = 1.12-1.39; p<0.001; I2 = 0%) than in normal-weight patients. Poor neurological outcome is associated with underweight, and low survival rate is associated with underweight and obesity in patients with ROSC after OHCA.

Association between body mass index and clinical outcomes in out-of-hospital cardiac arrest survivors treated with targeted temperature management

BACKGROUND

To determine the impact of body mass index (BMI) on clinical outcomes in out-of-hospital cardiac arrest (OHCA) survivors treated with targeted temperature management (TTM).

METHODS

We conducted a retrospective cohort study of 261 adult OHCA survivors who received complete TTM between January 2011 and December 2018 using data from the Research Patient Database Registry of Partners HealthCare system in Boston. Patients were categorized as underweight (BMI < 18.5 kg/m2), normal weight (BMI = 18.5-24.9 kg/m2), overweight (BMI = 25-29.9 kg/m2), and obese (BMI ≥ 30 kg/m2), according to the World Health Organization classification.

RESULTS

The average BMI was 28.9 ± 7.1 kg/m2. Patients with a higher BMI had higher rates of hypertension and diabetes mellitus, and were more likely to be witnessed on collapse. Patients with lower BMI levels had higher sequential organ failure assessment (SOFA) scores, blood urea nitrogen values, and mild thrombocytopenia rates (platelet count <150 K/μL) after the TTM treatment. The survival to discharge and favorable neurological outcome at discharge were reported in 117 (44.8%) and 76 (29.1%) patients, respectively. The survival at discharge, favorable neurologic outcomes at discharge, length of hospital admission, and the occurrence of acute kidney injury did not significantly differ between the BMI subgroups. In logistic regression model, BMI was not an independent predictor for survival at discharge (adjusted odds ratio 0.945, 95% CI 0.883-1.012, p = 0.108) nor for the favorable neurologic outcome at discharge (adjusted odds ratio 1.022, 95% CI 0.955-1.093, p = 0.528).

CONCLUSION

In OHCA patients treated with TTM, there was no significant difference across BMI subgroups for survival or favorable neurologic outcome at discharge.

Association between the body mass index and outcomes of patients resuscitated from out-of-hospital cardiac arrest: a prospective multicentre registry study

Background

The effects of the body mass index (BMI) on outcomes of patients resuscitated from cardiac arrest are controversial. Therefore, the current study investigated the association between the BMI and the favourable neurologic outcomes and survival to discharge of patients resuscitated from out-of-hospital cardiac arrest (OHCA).

Methods

This multicentre, prospective, nationwide OHCA registry-based study was conducted using data from the Korean Cardiac Arrest Resuscitation Consortium (KoCARC). We enrolled hospitals willing to collect patient height and weight and included patients who survived to the hospital between October 2015 and June 2018. The included patients were categorised into the underweight (< 18.5 kg/m²), normal weight (≥18.5 to < 25 kg/m²), overweight (≥25 to < 30 kg/m²), and obese groups (≥30 kg/m²) according to the BMI per the World Health Organization (WHO) criteria. The primary outcome was a favourable neurologic outcome; the secondary outcome was survival to discharge. Univariate and multivariate analyses were performed to investigate the association between BMI and outcomes.

Results

Nine hospitals were enrolled; finally, 605 patients were included in our analysis and categorised per the WHO BMI classification. Favourable neurologic outcomes were less frequent in the underweight BMI group than in the other groups (p = 0.002); survival to discharge was not significantly different among the BMI groups (p = 0.110). However, the BMI classification was not associated with favourable neurologic outcomes or survival to discharge after adjustment in the multivariate model.

Conclusion

The BMI was not independently associated with favourable neurologic and survival outcomes of patients surviving from OHCA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13049-021-00837-x.

Predictive Value of Estimated Lean Body Mass for Neurological Outcomes after Out-of-Hospital Cardiac Arrest

Background: Postcardiac arrest patients with a return of spontaneous circulation (ROSC) are critically ill, and high body mass index (BMI) is ascertained to be associated with good prognosis in patients with a critically ill condition. However, the exact mechanism has been unknown. To assess the effectiveness of skeletal muscles in reducing neuronal injury after the initial damage owing to cardiac arrest, we investigated the relationship between estimated lean body mass (LBM) and the prognosis of postcardiac arrest patients. Methods: This retrospective cohort study included adult patients with ROSC after out-of-hospital cardiac arrest from January 2015 to March 2020. The enrolled patients were allocated into good- and poor-outcome groups (cerebral performance category (CPC) scores 1–2 and 3–5, respectively). Estimated LBM was categorized into quartiles. Multivariate regression models were used to evaluate the association between LBM and a good CPC score. The area under the receiver operating characteristic curve (AUROC) was assessed. Results: In total, 155 patients were analyzed (CPC score 1–2 vs. 3–5, n = 70 vs. n = 85). Patients’ age, first monitored rhythm, no-flow time, presumed cause of arrest, BMI, and LBM were different (p < 0.05). Fourth-quartile LBM (≥48.98 kg) was associated with good neurological outcome of postcardiac arrest patients (odds ratio = 4.81, 95% confidence interval (CI), 1.10–25.55, p = 0.04). Initial high LBM was also a predictor of good neurological outcomes (AUROC of multivariate regression model including LBM: 0.918). Conclusions: Initial LBM above 48.98kg is a feasible prognostic factor for good neurological outcomes in postcardiac arrest patients.

Obese cardiogenic arrest survivors with significant coronary artery disease had worse in-hospital mortality and neurological outcomes

Cardiogenic arrest is the major cause of sudden cardiac arrest (SCA), accounting for 20% of all deaths annually. The association between obesity and outcomes in cardiac arrest survivors is debatable. However, the effect of obesity on the prognosis of patients with significant coronary artery disease (CAD) successfully resuscitated from cardiogenic arrest is unclear. Thus, the association between body mass index (BMI) and outcomes in cardiogenic arrest survivors with significant CAD was investigated. This multicentre retrospective cohort study recruited 201 patients from January 2011 to September 2017. The eligible cardiogenic arrest survivors were non-traumatic adults who had undergone emergency coronary angiography after sustained return of spontaneous circulation and had significant coronary artery stenosis. BMI was used to classify the patients into underweight, normal-weight, overweight, and obese groups (< 18.5, 18.5–24.9, 25.0–29.9, and ≥ 30 kg/m²; n = 9, 87, 72, and 33, respectively). In-hospital mortality and unsatisfactory neurological outcomes (cerebral performance scale scores = 3–5) were compared among the groups. The obese group presented higher in-hospital mortality and unsatisfactory neurological outcome risks than the normal-weight group (in-hospital mortality: adjusted hazard ratio = 4.27, 95% confidence interval (CI) 1.87–12.04, P = 0.008; unsatisfactory neurological outcomes: adjusted odds ratio = 3.33, 95% CI 1.42–8.78, P = 0.009). Subgroup analysis showed significantly higher in-hospital mortality in the obese patients than in the others in each clinical characteristic. In cardiogenic arrest survivors with significant CAD, obesity was associated with high risks of mortality and unsatisfactory neurological recovery.

The Crashing Obese Patient

The obesity pandemic now affects hundreds of millions of people worldwide. As obesity rates continue to increase, emergency physicians are called on with increasing frequency to resuscitate obese patients. This article discusses important anatomic, physiologic, and practical challenges imposed by obesity on resuscitative care. Impacts on hemodynamic monitoring, airway and ventilator management, and pharmacologic therapy are discussed. Finally, several important clinical scenarios (trauma, cardiac arrest, and sepsis), in which alterations to standard treatments may benefit obese patients, are highlighted.

Associations between Central Obesity and Outcomes of Adult In-hospital Cardiac Arrest: A Retrospective Cohort Study

To investigate the association between central obesity and outcomes following in-hospital cardiac arrest (IHCA). A single-centred retrospective study was conducted. Adult patients that experienced IHCA during 2006-2015 were screened. Body mass index (BMI) was calculated at hospital admission. Central obesity-related anthropometric parameters were measured by analysing computed tomography images. A total of 648 patients were included, with mean BMI of 23.0 kg/m2. The proportions of BMI-defined obesity in this cohort were underweight (13.1%), normal weight (41.4%), overweight (31.5%) and obesity (14.0%). The mean waist circumference was 85.9 cm with mean waist-to-height ratio (WHtR) of 0.53. The mean sagittal abdominal diameter was 21.2 cm with mean anterior and posterior abdominal subcutaneous adipose tissue (SAT) depths of 1.6 and 2.0 cm, respectively. Multivariate logistic regression analyses indicated BMI of 11.7-23.3 kg/m2 (odds ratio [OR]: 2.53, 95% confidence interval [CI]: 1.10-5.85; p-value = 0.03), WHtR of 0.49-0.59 (OR: 3.45, 95% CI: 1.56-7.65; p-value = 0.002) and anterior abdominal SAT depth <1.9 cm (OR: 2.84, 95% CI: 1.05-7.74; p-value = 0.04) were positively associated with the favourable neurological outcome. Central obesity was associated with poor IHCA outcomes, after adjusting for the effects of BMI.

Plasma Adipokines in Patients Resuscitated from Cardiac Arrest: Difference of Visfatin between Survivors and Nonsurvivors

Background

Adipokines are a group of cytokines or peptides secreted by adipose tissue to exert numerous biological functions. In the present study, we measured the plasma levels of four adipokines (adiponectin, leptin, fatty acid-binding protein 4 (FABP4), and visfatin) in cardiac arrest patients following return of spontaneous circulation (ROSC).

Methods

Totally, 21 patients who experienced cardiac arrest and successful ROSC with expected survival of at least 48 hours (from January 2016 to December 2017) were consecutively enrolled into this prospective observational clinical study. Of the 21 enrolled patients, ten survived, and other eleven died between 2 days and 6 months post ROSC. Venous blood was drawn at three time points: baseline (<1 hour post ROSC), 2 days post ROSC, and 7 days post ROSC. Plasma concentrations of adiponectin, leptin, FABP4, and visfatin were determined using commercial enzyme-linked immunosorbent assays.

Results

The plasma visfatin levels at 2 or 7 days post ROSC increased significantly compared with the baseline (P < 0.01), while plasma levels of adiponectin, leptin, and FABP4 did not change. Moreover, plasma visfatin levels in survivors at 2 or 7 days post ROSC were higher than those in nonsurvivors (P < 0.01). Plasma visfatin levels at 2 or 7 days post ROSC were negatively correlated with Acute Physiology and Chronic Health Evaluation (APACHE) II score and time to ROSC. Moreover, receiver operating characteristic curve analysis showed that the plasma visfatin levels at 2 or 7 days post ROSC were good predictors for survival of the patients.

Conclusion

Elevated plasma visfatin levels may be a marker for better outcome of cardiac arrest patients post ROSC.

Retrospective Study Using Computed Tomography to Compare Sufficient Chest Compression Depth for Cardiopulmonary Resuscitation in Obese Patients

Background This study aimed to investigate the relationship between body mass index (BMI) and sufficient chest compression depth (CCD) in obese patients by a mathematical model. Methods and Results This retrospective analysis was performed with chest computed tomography images conducted between 2006 and 2018. We classified the selected individuals into underweight (<18.5), normal weight (≥18.5, <25), overweight (≥25, <30), and obese (≥30) groups according to BMI (kg/m2). We defined heart compression fraction (HCF) as [Formula: see text] and estimated under-HCF (the value of HCF <20%), and over-HCF (the residual depth <2 cm after simulation with chest compression depth 5 and 6 cm). We compared these outcomes between BMI groups. Of 30 342 individuals, 8856 were selected and classified into 4 BMI groups from a database. We randomly selected 100 individuals in each group and analyzed a total of 400 individuals' cases. Higher BMI groups had a significantly decreased HCF with both 5 and 6 cm depth (P<0.001). The proportion of under-HCF with both depths increased according to BMI group, whereas the proportion of over-HCF decreased except for the 5 cm depth (P<0.001). The adjusted odds ratio of under-HCF, according to BMI group after adjustment of age and sex, was 7.325 (95% CI, 3.412-15.726; P<0.001), with 5 cm and 10.517 (95% CI, 2.353-47.001; P=0.002) with 6 cm depth, respectively. Conclusions The recommended chest compression depth of 5 to 6 cm in the current international guideline is unlikely to provide sufficient ejection fraction during cardiopulmonary resuscitation in obese patients.

Systematic review of the relationship between comorbidity and out-of-hospital cardiac arrest outcomes

OBJECTIVES

To assess the current evidence on the effect pre-arrest comorbidity has on survival and neurological outcomes following out-of-hospital cardiac arrest (OHCA).

DESIGN

Systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

DATA SOURCES

MEDLINE, Ovid Embase, Scopus, CINAHL, Cochrane Library and MedNar were searched from inception to 31 December 2018.

ELIGIBILITY CRITERIA

Studies included if they examined the association between prearrest comorbidity and OHCA survival and neurological outcomes in adult or paediatric populations.

DATA EXTRACTION AND SYNTHESIS

Data were extracted from individual studies but not pooled due to heterogeneity. Quality of included studies was assessed using the Newcastle-Ottawa Quality Assessment Scale.

RESULTS

This review included 29 observational studies. There were high levels of clinical heterogeneity between studies with regards to patient recruitment, inclusion criteria, outcome measures and statistical methods used which ultimately resulted in a high risk of bias. Comorbidities reported across the studies were diverse, with some studies reporting individual comorbidities while others reported comorbidity burden using tools like the Charlson Comorbidity Index. Generally, prearrest comorbidity was associated with both reduced survival and poorer neurological outcomes following OHCA with 79% (74/94) of all reported adjusted results across 23 studies showing effect estimates suggesting lower survival with 42% (40/94) of these being statistically significant. OHCA survival was particularly reduced in patients with a prior history of diabetes (four out of six studies). However, a prearrest history of myocardial infarction appeared to be associated with increased survival in one of four studies.

CONCLUSIONS

Prearrest comorbidity is generally associated with unfavourable OHCA outcomes, however differences between individual studies makes comparisons difficult. Due to the clinical and statistical heterogeneity across the studies, no meta-analysis was conducted. Future studies should follow a more standardised approach to investigating the impact of comorbidity on OHCA outcomes.

PROSPERO REGISTRATION NUMBER

CRD42018087578.

Obesity is associated with poor prognosis in cardiogenic arrest survivors receiving coronary angiography

BACKGROUND

The role of body mass index (BMI) in clinical outcomes in patients resuscitated from cardiac arrest (CA) has recently drawn attention. We evaluated the effect of BMI on the prognosis of patients successfully resuscitated from cardiogenic arrest.

METHODS

This retrospective cohort study included 273 non-traumatic adult cardiogenic arrest survivors receiving coronary angiography after return of spontaneous circulation in three hospitals from January 2011 to September 2017. These patients were classified as underweight, normal-weight, overweight, and obese, based on BMI (<18.5; 18.5-24.9; 25.0-29.9; and ≥30 kg/m², respectively). In-hospital mortality and poor neurological outcomes were compared among groups.

RESULTS

The obese group had significantly higher rates of in-hospital mortality and poor neurological outcomes (cerebral performance scale = 3-5) than did the other groups (for underweight, normal-weight, overweight, and obese groups, in-hospital mortality rates were 38.5%, 29.8%, 39.0%, and 64.1%, respectively, p = 0.002; poor neurological outcomes were 53.9%, 43.8%, 47.0%, and 71.8%, respectively, p = 0.02). The obese group exhibited higher risks of in-hospital mortality and poor neurological outcomes than did the normal-weight group (in-hospital mortality: adjusted hazard ratio (aHR) = 5.21, 95% confidence interval (CI) 2.16-10.32, p < 0.001; poor neurological outcomes: aHR = 3.77, 95% CI 1.69-8.36, p = 0.002).

CONCLUSION

Obesity was associated with higher risks of in-hospital mortality and poor neurological recovery.

The effects of thoracic cage dimension and chest subcutaneous adipose tissue on outcomes of adults with in-hospital cardiac arrest: A retrospective study

BACKGROUND

The associations between thoracic cage dimension, chest subcutaneous adipose tissue (SAT) depth and outcomes of adults with in-hospital cardiac arrest (IHCA) remain unknown.

METHODS

We retrospectively evaluated IHCA patients between January 2016 and October 2017. The thoracic cage transverse diameter, internal AP diameter, cross-sectional area, anterior and posterior SAT depths were measured in computed-tomography (CT) images. Using logistic regression models, we determined the adjusted associations between thoracic cage dimension, SAT depths and the prognosis for IHCA. The primary outcome was sustained return of spontaneous circulation (ROSC) and the secondary outcome was survival to hospital discharge.

RESULTS

Among 423 IHCA patients, 258 patients achieved ROSC and 70 survived to discharge. Smaller cross-sectional area and posterior SAT depth were significantly related to ROSC. Smaller posterior SAT depth was associated with ROSC. After multivariate adjustment, the smaller cross-sectional area was independently associated with ROSC (Odds ratio [OR] 0.99, 95% confidence interval [95%CI] 0.99-1.00; p = 0.008) and survival to discharge (OR 0.99, 95%CI 0.98-1.00; p = 0.024), and the smaller posterior SAT depth was independently related to ROSC (OR 0.65, 95%CI 0.44-0.96; p = 0.030), whereas no relation to survival to discharge was found.

CONCLUSIONS

In adults with IHCA, the smaller thoracic cage dimension and posterior SAT depth are associated with better survival. An adjustable compression depth based on the thoracic cage dimension might be better than the "one-size-fits-all" compression depth for resuscitating CA patients. In addition, physicians should pay extra attention to compression efficacy when resuscitating obese patients.

Associations between body size and outcomes of adult in-hospital cardiac arrest: A retrospective cohort study

AIM

Animal studies have demonstrated that hemodynamic-directed cardiopulmonary resuscitation (CPR) improves outcomes following cardiac arrest compared with the "one-size-fits-all" algorithm. We investigated whether body size of patients is correlated with outcomes of in-hospital cardiac arrest (IHCA).

METHODS

A retrospective study in a single centre was conducted. Adult patients experiencing IHCA between 2006 and 2015 were screened. Body mass index (BMI) was calculated using body weight and height measured at hospital admission. Thoracic anteroposterior diameter (APD) was measured by analysing computed tomography images. Multivariate logistic regression analysis was used to study the associations between independent variables and outcomes. Generalised additive models were used to identify cut-off points for continuous variables.

RESULTS

A total of 766 patients were included, and 60.4% were male. Their mean age was 62.8 years. Mean BMI was 22.9 kg/m², and the mean thoracic APD was 21.4 cm. BMI > 23.2 kg/m² was inversely associated with a favourable neurological outcome (odds ratio [OR]: 0.30, 95% confidence interval [CI]: 0.13-0.68; p-value = 0.004), while thoracic APD was not. When the interaction term was analysed, BMI > 23.2 (kg/m²) × thoracic APD > 18.5 (cm) was inversely associated with both a favourable neurological outcome (OR: 0.33, 95% CI: 0.16-0.69; p-value = 0.003) and survival to hospital discharge (OR: 0.46, 95% CI: 0.26-0.81; p-value = 0.007).

CONCLUSION

Higher BMI and thoracic APD was correlated with worse outcomes following IHCA. For those patients, it might be better to perform CPR under guidance of physiological parameters rather than a "one-size-fits-all" resuscitation algorithm to improve outcomes.

Morbid obesity impairs adequacy of thoracic compressions in a simulation-based model

Adequate cardiopulmonary resuscitation is an important predictor of survival, however, obesity provides a significant physical barrier to thoracic compressions. This study explores the effect of morbid obesity on compression adequacy. We performed a prospective randomised controlled crossover study, assessing the adequacy of thoracic compressions on a manikin modified to emulate a morbidly obese patient. Participants recruited from critical care departments were randomised to perform continuous compressions for two minutes on each manikin. Accelerometers were used to measure thoracic wall movement. The primary endpoint was a composite measure of compression adequacy (rate, depth and recoil). Secondary endpoints were the individual components of the composite outcome and measures of perceived effectiveness, fatigue, and pain. One hundred and one participants were recruited. There was a significant difference between the obese and control groups in the composite endpoint (4% versus 30%, <i>P</i> <0.001), as well as the individual components of adequacy (<i>P</i> <0.01 for all). Quartile data showed significant deterioration in adequacy of depth and recoil in both groups, and this occurred significantly earlier in the obese group (<i>P</i> ≤0.001). Participants' perception of effectiveness was significantly lower (<i>P</i> ≤0.001) in the obese group, and levels of fatigue (<i>P</i> ≤0.001) and pain (<i>P</i> ≤0.001) significantly higher. Morbid obesity impairs the adequacy of thoracic compressions for trained rescuers in a simulation-based model. Participants were not fully aware of how ineffective compressions were. There is evidence of earlier fatigue further reducing effectiveness. These findings have significant implications for the training of rescuers in a clinically relevant population and the planning of future research.

Microcirculation-mediated preconditioning and intracellular hypothermia

Microcirculation is a network of perfused capillaries that connects macrocirculation with the cells. Although research has provided insight into microcirculatory blood flow, our knowledge remains limited. In this article, we propose a new role of microcirculation in physiological and shock states. In healthy individuals, microcirculation maintains cellular homeostasis via preconditioning. When blood volume decreases, the ensuing microcirculatory changes result in heterogeneity of perfusion and tissue oxygenation. Initially, this is partly compensated by the preserved autoregulation and the increase in the metabolism rate of cells, but at later stages, the loss of autoregulation activates the cascade of intracellular hypothermia.

Effect of body mass index on survival after sudden cardiac arrest

BACKGROUND

Although elevated body mass index (BMI) is a risk factor for cardiac disease, patients with elevated BMI have better survival in the context of severe illness, a phenomenon termed the "obesity paradox."

HYPOTHESIS

Higher BMI is associated with lower mortality in sudden cardiac arrest (SCA) survivors.

METHODS

Data were collected on 1433 post-SCA patients, discharged alive from the hospitals of the University of Pittsburgh Medical Center between 2002 and 2012. Of those, 1298 patients with documented BMI during the index hospitalization and follow-up data constituted the study cohort.

RESULTS

In the overall cohort, 30 patients were underweight (BMI <18.5 kg/m² ), 312 had normal weight (BMI 18.5-24.9 kg/m² ), 417 were overweight (BMI 25.0-29.9 kg/m² ), and 539 were obese (BMI ≥30 kg/m² ). As expected, the prevalence of coronary artery disease, myocardial infarction, diabetes mellitus, and hypertension increased significantly with increasing BMI. Over a median follow-up of 3.6 years, 602 (46%) patients died. Despite higher prevalence of cardiovascular comorbidities in more obese patients, a higher BMI was associated with lower all-cause mortality on univariate analysis (hazard ratio: 0.86 per increase by 1 BMI category, 95% confidence interval: 0.78-0.94, P = 0.002) and multivariate analysis after adjusting for unbalanced baseline comorbidities (hazard ratio: 0.86 per increase by 1 BMI category, 95% confidence interval: 0.77-0.96, P = 0.009).

CONCLUSIONS

Higher BMI is associated with lower all-cause mortality in survivors of SCA, suggesting that the obesity paradox applies to the post-arrest population. Further investigation into its mechanisms may inform the management of post-SCA patients.

Body mass index and thoracic subcutaneous adipose tissue depth: possible implications for adequacy of chest compressions

Objective

Adequacy of cardiopulmonary resuscitation relies on compression of the thoracic cage to produce changes in intra-thoracic pressures sufficient to generate a pressure gradient. In order to evaluate the efficacy of cardiopulmonary resuscitation in morbid obesity, it is first necessary to determine the depth of thoracic subcutaneous adipose tissue (SAT) and to correlate this with body mass index (BMI).

Results

Computerised-tomography images of the thorax of 55 patients with a diagnosis of obesity or morbid obesity (mean BMI 45.95 kg/m²) were evaluated to determine the depth of SAT at the level at which chest compressions would be applied by a trained rescuer, and correlated with BMI. Mean anterior SAT was 36.53 mm, and mean posterior SAT was 50.73 mm. There was a significant correlation between BMI and anterior and posterior SAT for males (p < 0.05 for both), and females (p < 0.05 for both). The slope of the functions was considered sufficiently close to allow combining the data. This also showed a significant correlation between SAT and BMI (p < 0.01 for both). Both anterior and posterior SAT is correlated with BMI. This data allows development of a model to explore the efficacy of chest compressions in morbid obesity.

Electronic supplementary material

The online version of this article (10.1186/s13104-017-2918-9) contains supplementary material, which is available to authorized users.

Association of body mass index with clinical outcomes for in-hospital cardiac arrest adult patients following extracorporeal cardiopulmonary resuscitation

BACKGROUND

Obesity might be associated with disturbance of cannulation in situation of extracorporeal cardiopulmonary resuscitation (ECPR). However, limited data are available on obesity in the setting of ECPR. Therefore, we investigated the association between body mass index (BMI) and clinical outcome in patients underwent ECPR.

METHODS

From January 2004 to December 2013, in-hospital cardiac arrest patients who had ECPR were enrolled from a single-center registry. We divided patients into four group according to BMI defined with the WHO classification (underweight, BMI < 18.5, n = 14; normal weight, BMI = 18.5-24.9, n = 118; overweight, BMI = 25.0-29.9, n = 53; obese, BMI ≥ 30, n = 15). The primary outcome was survival to hospital discharge.

RESULTS

Analysis was carried out for a total of 200 adult patients (39.5% females). Their median BMI was 23.20 (interquartile range, 20.93-25.80). The rate of survival to hospital discharge was 31.0%. There was no significant difference in survival to hospital discharge among the four groups (underweight, 35.7%; normal, 31.4%; overweight, 30.2%; obese, 26.7%, p = 0.958). Neurologic outcomes (p = 0.85) and procedural complications (p = 0.40) were not significantly different among the four groups either. SOFA score, initial arrest rhythm, and CPR to extracorporeal membrane oxygenation (ECMO) pump on time were significant predictors for survival to discharge, but not BMI.

CONCLUSION

BMI was not associated with in-hospital mortality who underwent ECPR. Neurologic outcomes at discharge or procedural complications following ECPR were not related with BMI either.