Outcome of Morbid Obesity in the Intensive Care Unit

The micronutrient content of the diet is correlated with serum glucose biomarkers and lipid profile and is associated with the odds of being overweight/obese-a case-control study

Background

A low micronutrient intake has been reported to contribute to the double-burden of obesity, increasing the risk for chronic diseases such as cardiovascular disease, diabetes, cancer, and mental disorders. This case-control study compared micronutrient intake profiles in overweight/obese vs. normal-weight individuals. We hypothesized that a low intake of certain micronutrients would increase the odds of being overweight/obese.

Methods

The case group (n = 812 adults) consisted of individuals with a BMI of ≥25  kg/m², and the control group (n = 793) had BMIs of 17.9-24.9  kg/m². A validated 124-item food frequency questionnaire was used to determine micronutrient-related dietary-quality, using the index of nutritional quality (INQ), calculated as the fraction of a micronutrient consumed vs. its dietary requirement. In addition, body surface area (BSA) was calculated according to the Mosteller formula.

Results

The control group had significantly higher INQ-scores of vitamin A, vitamin C, calcium, magnesium, and selenium compared to the case group. Furthermore, individuals with normal BSA (≤1.91 m² for men; ≤1.71  m² for women) had significantly higher INQ scores of vitamin C, calcium, magnesium, and zinc compared to participants with high BSA. In multivariable adjustment regression models, INQs of vitamin C (OR_BMI = 0.79, 95%CI: 0.64-0.97; OR_BSA = 0.81, 95%CI, 0.68-0.97) and magnesium (OR_BMI = 0.69, 95%CI: 0.47-0.99; OR_BSA = 0.71, 95%CI: 0.52-0.97) were significantly associated with the odds of obesity/overweight (in both BMI and BSA categories).

Conclusion

The significant association between micronutrient levels of the diet, especially of vitamin C and magnesium, with both obesity criteria, emphasized the importance of certain micronutrients in the obesity/overweight causal network.

Impact of Obesity on In-Hospital Morbidity and Mortality Among Patients Admitted for Acute Exacerbations of Chronic Obstructive Pulmonary Disease (COPD)

Background Obesity has been considered to be a risk factor for increased morbidity and mortality among patients with cardiopulmonary diseases. The burden of chronic obstructive pulmonary disease (COPD) and obesity is very high in the United States. We aimed to use the National Inpatient Sample (NIS) to evaluate the impact of obesity on the outcomes of patients hospitalized with COPD exacerbation. Materials & Methods This is a retrospective cohort study from the NIS database involving adult patients hospitalized for COPD exacerbation in the year 2019 obtained using the international classification of diseases, 10^th revision coding system (ICD-10). Obese and morbidly obese subgroups were identified. Statistical analyses were done using the Stata software, and regression analysis was performed to calculate odds ratios. Adjusted odds ratios (aOR) were calculated after adjusting for potential confounders. Results Among patients hospitalized for COPD exacerbations, mortality rates were lower among obese and morbidly obese patients; aOR 0.72 [0.65, 0.80] and aOR 0.88 [0.77-0.99], respectively. Obese and morbidly obese were more likely to require non-invasive ventilation aOR 1.63 [1.55, 1.7] and aOR 1.93 [1.85-2.05], respectively, and were more likely to require mechanical ventilation aOR 1.25 [1.19, 1.31], and aOR 1.53 [1.44-1.62], respectively. The tracheostomy rate was 1.17%, 0.83%, and 0.38% among patients with morbid obesity, obesity, and nonobese patients, respectively. Obese (aOR 1.11 [1.07-1.14]) and morbidly obese patients (aOR 1.21 [1.16-1.26]) had higher odds of being discharged on home oxygen and to a skilled nursing facility (SNF), aOR 1.32[1.27-1.38] and aOR 1.37 [1.3-1.43], respectively. Average hospital charges and length of hospitalization were significantly higher for morbidly obese and obese patients as compared to non-obese patients (p < 0.01). Conclusions Among admissions for COPD exacerbation, the rates of non-invasive ventilation, mechanical ventilation, tracheostomy, discharge with supplemental oxygen, length of hospitalization, hospitalization charges, and discharge to an SNF were higher among obese patients representing a higher morbidity and healthcare utilization in this group. This, however, did not translate into increased mortality among obese patients admitted with COPD exacerbations, and further randomized controlled trials are required to confirm our findings.

Observational, prospective, single-center study: Should body mass index be added to the scoring criteria of hepatic critically ill patients in the intensive care unit

BACKGROUND

Obesity has recently become more prevalent, and thus the coexistence of liver cirrhosis with obesity has become very pervasive. The purpose of this study is to investigate the correlation between abnormal body mass index (BMI) (overweight and obese) and clinical outcomes in critically ill cirrhotic patients.

METHODS

This is a single-center, prospective observational study of cirrhotic patients admitted to the intensive care unit for either medical or surgical indications in the period from February 2018 to December 2020. Patients were categorized based on their body mass index and the reason for admission to the intensive care unit (ICU).

RESULTS

The current study enrolled 517 patients; 39.3% were overweight, and 19.5% were obese (85% were class 1 and 2). Surgical subgroup analysis revealed that the hospital stay was shorter in the obese than average weight patients (p-value= 0.039), and ICU stay was shorter in overweight patients than patients with average weight (p-value= 0.022). The incidence of acute kidney injury was shorter in the obese group than in overweight and average-weight patients (p-value= 0.045). The medical subgroup analysis revealed that the need for noninvasive ventilation was lower in the obese and overweight groups than in the normal group (p-value= 0.040).

CONCLUSIONS

Despite having similar Child-Pugh (CP) and Sequential Organ Failure Assessment Score (SOFA) scores on admission, obese patients had better outcomes than non-obese patients, demonstrating the obesity paradox. Further research is required on BMI as a predictive score in a patient with critical cirrhosis as an indicator of obesity.

Clinical Outcomes with Ertapenem for Pneumonia in Obese versus Nonobese Patients

The objective of this study was to compare the rate of pneumonia resolution in obese (body mass index [BMI], ≥30 kg/m2) and nonobese (BMI, <30 kg/m2) patients treated with 1 gram ertapenem daily. In this retrospective cohort study, we evaluated patients treated at The Ohio State University Wexner Medical Center between 1 January 2015 and 31 August 2020. Patients were included if they were between 18 and 89 years old and received ertapenem for at least 48 hours for pneumonia treatment. Patients were excluded if they were pregnant, were incarcerated, had renal impairment, received antibiotics with Gram-negative activity for a significant period prior to or in addition to ertapenem, and had other concomitant deep-seated infections. The primary outcome of clinical resolution was defined as meeting any of the following three criteria in order of evaluations: discontinuation of antibiotics by day 8 of therapy, afebrile while on ertapenem in addition to a decrease in white blood cell count, or improvement on chest radiograph at day 7 of therapy. A multivariable logistic regression analysis was performed to examine the association between obesity and clinical resolution, while adjusting for proven confounders. There were 76 nonobese and 65 obese patients included. The median patient BMI was 23.7 kg/m2 (21.0 to 26.9) and 35.0 kg/m2 (32.8 to 39.8) for the nonobese and obese cohorts, respectively. Clinical resolution was achieved in 78% (59/76) of nonobese and 75% (49/65) of obese patients (P = 0.75) without an observed difference in the regression model. Outcomes were similar in obese and nonobese patients treated with 1 gram of ertapenem daily for pneumonia.

Obesity and Critical Illness in COVID-19: Respiratory Pathophysiology

OBJECTIVE

Recent cohort studies have identified obesity as a risk factor for poor outcomes in coronavirus disease 2019 (COVID-19). To further explore the relationship between obesity and critical illness in COVID-19, the association of BMI with baseline demographic and intensive care unit (ICU) parameters, laboratory values, and outcomes in a critically ill patient cohort was examined.

METHODS

In this retrospective study, the first 277 consecutive patients admitted to Massachusetts General Hospital ICUs with laboratory-confirmed COVID-19 were examined. BMI class, initial ICU laboratory values, physiologic characteristics including gas exchange and ventilatory mechanics, and ICU interventions as clinically available were measured. Mortality, length of ICU admission, and duration of mechanical ventilation were also measured.

RESULTS

There was no difference found in respiratory system compliance or oxygenation between patients with and without obesity. Patients without obesity had higher initial ferritin and D-dimer levels than patients with obesity. Standard acute respiratory distress syndrome management, including prone ventilation, was equally distributed between BMI groups. There was no difference found in outcomes between BMI groups, including 30- and 60-day mortality and duration of mechanical ventilation.

CONCLUSIONS

In this cohort of critically ill patients with COVID-19, obesity was not associated with meaningful differences in respiratory physiology, inflammatory profile, or clinical outcomes.

Microfluidics for sepsis early diagnosis and prognosis: a review of recent methods

Sepsis is a complex disorder of immune system response to infections that can be caused by a wide range of clinical contexts. Traditional methods for sepsis detection include molecular diagnosis, biomarkers either based on protein concentration or cell surface expression, and microbiological cultures. Development of point-of-care (POC) instruments, which can provide high accuracy and consume less time, is in unprecedented demand. Within the past few years, applications of microfluidic systems for sepsis detection have achieved excellent performance. In this review, we discuss the most recent microfluidic applications specifically in sepsis detection, and propose their advantages and disadvantages. We also present a comprehensive review of other traditional and current sepsis diagnosis methods to obtain a general understanding of the present conditions, which can hopefully direct the development of a new sepsis roadmap.

Obesity Impacts Mortality and Rate of Revascularizations Among Patients With Acute Myocardial Infarction: An Analysis of the National Inpatient Sample

Background Obesity is now a recognized chronic comorbid condition which is highly prevalent in the United States. Obesity poses several health risks, affecting multiple organ systems. The cardiovascular system is particularly affected by obesity including its role in atherosclerotic disease and hence myocardial infarction (MI) from atheromatous plaque events. However, multiple population-based studies have shown mixed outcomes in obese patients who have acute MI. This study aimed to determine if obesity paradoxically improved outcomes in patients with acute myocardial infarction (AMI) as well as compare outcomes of mild to moderately obese patients and morbidly obese patients to non-obese patients. Materials and methods Data was obtained from the Nationwide Inpatient Sample (NIS) for 2016 and 2017. The study included adult patients with a principal discharge diagnosis of AMI. This group was divided into ST segment elevation myocardial infarction (STEMI) and non-ST segment myocardial infarction (NSTEMI). Obese patients were subdivided into two groups: mild-moderate obesity and morbid obesity. Primary outcome compared inpatient mortality. Secondary outcomes included rate of percutaneous coronary intervention (PCI), coronary artery bypass grafting (CABG), composite revascularization, mean length of hospitalization, total hospital charges, and rates of complications. Results In patients with STEMI, mild to moderately obese patients had lower odds of mortality (aOR: 0.80, 95% CI: 0.715-0.906, p < 0.001) compared to non-obese patients. However, morbidly obese patients had higher odds of mortality (aOR: 1.26, 95% CI: 1.100-1.446, p < 0.001) compared to non-obese patients. Mild to moderately obese patients had higher odds of composite revascularization (aOR: 1.24, 95% CI: 1.158-1.334, p < 0.001), PCI (aOR: 1.08, 95% CI: 1.054-1.150, p = 0.014), and CABG (aOR: 1.46, 95% CI: 1.313-1.626, p < 0.001). Conclusion The degree of obesity affects outcome of patients with AMI. Cardiovascular interventions during hospitalizations for AMI also varied with degree of obesity. This may have affected the outcome, especially among morbidly obese patients.

The Efficacy of In-Reach Rehabilitation in Morbidly Obese Post Septic Patients: Two Retrospective Case Reports

Objective

To report the functional outcomes of two patients with morbid obesity (> 250 kg) who received in-reach rehabilitation after hospitalization for sepsis in Sydney, Australia.

Case reports

A retrospective review of hospital charts was performed with the informed consent of both patients. Body mass index, demographics, length of stay, functional status at admission and discharge, medical comorbidities, social history, hospital course, equipment needs, therapy methods used, and discharge disposition were compared.

Results

Both patients had a positive outcome. Function improved in case 1, from requiring hoist transfers, to mobilizing 80 m with 2 assistants. The patient was transferred to a subacute rehabilitation facility, but did not make any gain in Functional Independence Measure. Function improved in case 2, from requiring 2 assistants to walk with a frame, to walking independently with a 4-wheeled walker. The patient was discharged home from the acute hospital, with a minimal Functional Independence Measure gain of 8. Both patients lost approximately 45 kg during acute hospitalization.

Conclusion

These case reports demonstrate that in-reach rehabilitation can play an important role in the functional recovery of morbidly obese patients hospitalized with severe sepsis. This report also highlights the need for preventive interventions to reduce avoidable acute hospital presentations and to prevent functional decline.

High fat diet accelerates and exacerbates microgliosis and neuronal damage/death in the somatosensory cortex after transient forebrain ischemia in gerbils

Obesity has been known as an independent risk factor for stroke. Effects of high-fat diet (HFD)-induced obesity on neuronal damage in the somatosensory cortex of animal models of cerebral ischemia have not been studied yet. In this study, HFD-induced obesity was used to study the impact of obesity on neuronal damage/loss and microgliosis in the somatosensory cortex of a gerbil model of 5-min transient forebrain ischemia. We used gerbils fed normal diet (ND) and HFD and chronologically examined microgliosis (microglial cell activation) by ionized calcium-binding adapter molecule 1 (Iba-1) immunohistochemistry. In addition, we examined neuronal damage or death by using neuronal nuclear protein (NeuN, a neuronal marker) immunohistochemistry and Fluoro-Jade B (F-J B, a marker for neuronal degeneration) histofluorescence staining. We found that ischemia-induced microgliosis in ND-fed gerbils was increased from 2 days post-ischemia; however, ischemia-mediated microgliosis in HFD-fed gerbils increased from 1 day post-ischemia and more accelerated with time than that in the ND-fed gerbils. Ischemia-induced neuronal death/loss in the somatosensory cortex in the ND-fed gerbils was apparently found at 5 days post-ischemia. However, in the HFD-fed gerbils, neuronal death/loss was shown from 2 days post-ischemia and progressively exacerbated at 5 days post-ischemia. Our findings indicate that HFD can evoke earlier microgliosis and more detrimental neuronal death/loss in the somatosensory cortex after transient ischemia than ND evokes.

Association Between Estimated Pharmacokinetic/Pharmacodynamic Predictions of Efficacy and Observed Clinical Outcomes in Obese and Nonobese Patients With Enterobacteriaceae Bloodstream Infections

Background

Evidence on pharmacokinetic/pharmacodynamic (PK/PD) alterations and clinical outcomes in obese patients with serious infections remains limited. This study aimed to evaluate predicted PK/PD indices of efficacy and observed clinical outcomes between obese and nonobese patients receiving cefepime or piperacillin-tazobactam for Enterobacteriaceae bacteremia.

Methods

This was a retrospective study of adult inpatients from 1/2012 to 9/2015 with Enterobacteriaceae bacteremia who received empiric cefepime or piperacillin-tazobactam. The primary outcome was clinical cure. First-dose free-drug exposure was estimated via predicted concentrations generated from population PK analyses and used to assess PD target attainment (>50% fT > minimum inhibitory concentration [MIC]) for the specific Enterobacteriaceae isolate. Multivariable logistic regression was utilized to identify independent predictors of clinical cure.

Results

One hundred forty-two patients were included, 57 obese and 85 nonobese. Clinical cure was achieved in 68.4% of obese and 62.4% of nonobese patients (P = .458). No significant difference in outcomes was observed when evaluated by World Health Organization (WHO) obesity classes. The PK/PD target was achieved in 98.2% of obese and 91.8% of nonobese patients (P = .144). Independent predictors of clinical cure were immunosuppression and a shorter duration of bacteremia. Obesity was not identified as a significant predictor of clinical outcomes.

Conclusions

Neither predicted PK/PD parameters nor clinical outcomes differed significantly between obese and nonobese patients treated with piperacillin-tazobactam or cefepime. As the majority of patients received extended-infusion piperacillin-tazobactam for bacteremia due to pathogens with low MICs, the potentially detrimental pathophysiologic derangements caused by obesity may not have been realized. Further studies are warranted to establish the optimal treatment of serious infections in obese patients.

Obesity as a Risk Factor Among Hospitalized Patients with Infective Endocarditis

Objective

Obesity contributes to diagnostic and management challenges for many hospitalized patients. The impact of obesity on in-hospital outcomes in patients with infective endocarditis has not been studied and was the focus of this investigation.

Method

We used the 2013 and 2014 Nationwide Inpatient Sample to identify adults ≥18 years of age with a principle diagnosis of endocarditis. We divided the sample into 2 groups based on presence of absence of obesity. Multivariate linear and logistic regression analysis was used to compare in-hospital mortality, valvular replacement, length of stay (LOS), and hospitalization charges.

Results

A total of 24 494 adults 18 years and older were hospitalized with infective endocarditis, of which 2625 were classified as obese. Patients with obesity were older (mean age, 57.8 ± 0.3 vs 54.3 ± 0.6 years; P < .01), more likely to be female (50.1% vs 36.1%; P < .01), and had more comorbidities (Charlson comorbidity score ≥ 3, 50.6% vs 28.8%; P < .01). Multivariate regression analysis found no differences between the 2 groups for mortality or repairs or replacements for any valve. On evaluation of resource utilization, patients with obesity had longer average LOS (13.9 days; confidence interval [CI], 12.7–15.1 vs 12.4 days; CI, 12.0–12.8; P = .016) and higher total hospital charges (US $160 789.90; CI, $140.922.40–$180 657.50 vs US $130 627.20; CI, $123 916.70–$137 337.70; P <.01). After adjustment for LOS for total hospital charges, there was no observed difference $11436.26 (CI, -$6649.07–$29521.6; P = .22).

Conclusions

. Obesity does not significantly impact in-hospital mortality or surgical valvular interventions among patients hospitalized with infective endocarditis, but obesity is associated with increased utilization of hospital resources.

Impact of the Time to Initiation of Parenteral Nutrition on Patient Outcomes in Critically Ill Adults

Background:

The optimal time to initiate parenteral nutrition (PN) in critically ill adults in whom enteral nutrition is not feasible is controversial.

Objective:

The objectives were to compare in-hospital mortality and hospital length of stay in patients initiated on PN within 7 days or after 7 days of poor nutrient intake.

Methods:

This single-center, retrospective study included critically ill adult patients who received at least 2 consecutive days of PN during hospitalization from May 2014 to July 2016.

Results:

The median duration of PN (interquartile range) was 8 (5-13) days. In total, 110 patients received PN within 7 days of poor nutrient intake while 49 patients received PN after 7 days of poor nutrient intake. There was no statistically significant difference in in-hospital mortality between groups (29.09% vs 18.37%, P = .1535). Patients initiated within 7 days had a significantly shorter median hospital length of stay than patients initiated after 7 days (20 days vs 27 days, P = .0013). There were 69 patients who were classified as obese. Obese patients initiated within 7 days had a significantly shorter median hospital length of stay than obese patients initiated after 7 days (17 days vs 33 days, P = .0007).

Conclusions:

Time to initiation of PN did not impact in-hospital mortality. However, there was an association between early initiation of PN and a shorter hospital length of stay that was most pronounced among obese patients.

The ABCDs of Managing Morbidly Obese Patients in Intensive Care Units

More than one-third of the US adult population and 17% of the youth are now obese, and obesity is associated with more than $147 billion a year in health care costs. Critical care nurses should understand the physiological differences and practice guidelines for patients with a body mass index greater than 30. The ABCD approach encompasses key clinical concepts in the management of critically ill obese and morbidly obese patients, including management of airways and breathing, minimizing nurses' back and other injuries, increasing awareness of bias, circulation problems, risks of decubitus ulcers and other skin breakdown, differences in drug calculations and metabolism, limitations in diagnostic equipment and imaging, diet and nutritional recommendations, and concerns with durable medical equipment.

Body Mass Index and Intensive Care Unit Outcomes in African American Patients

PURPOSE

We sought to determine whether body mass index (BMI) is associated with worse intensive care unit (ICU) outcomes among Black patients.

METHODS

Patients admitted to the medical ICU during 2012 were categorized into six BMI groups based on the World Health Organization criteria. ICU mortality, ICU and hospital length of stay (LOS), need for and duration of mechanical ventilation and organ failure rate were assessed.

RESULTS

A total of 605 patients with mean age 58.9 ± 16.0 years were studied. Compared with those with normal BMI, obese patients had significant higher rates of hypertension, diabetes mellitus and obstructive sleep apnea diagnoses (P<.001 for all). A total of 100 (16.5%) patients died during their ICU stay. Obesity was not associated with increased odds of ICU mortality (OR=.58; 95% CI, .16-2.20). Moreover, improved survival was observed for class II obese patients (OR, .031; 95% CI, .001-.863). There were no differences in the need for and duration of mechanical ventilation between the BMI groups. However, ICU and hospital LOS were significantly longer in patients with obesity.

CONCLUSION

Obesity was not associated with increased ICU mortality; however, obesity was associated with increased comorbid illness and with significant longer ICU and hospital length of stay.

Effect of body mass index on the outcome of surgical patients receiving extracorporeal devices (VV ECMO, pECLA) for respiratory failure

INTRODUCTION

To determine whether obese surgical patients are at a significant disadvantage in terms of outcomes after extracorporeal device (ECD) support, such as veno-venous extracorporeal membrane oxygenation (VV ECMO) or pumpless extracorporeal lung assist (pECLA), for respiratory failure, the relationship between body mass index (BMI) and hospital outcomes was analyzed.

METHODS

This retrospective study included data on patients who were supported with an ECD between January 1, 2008 and December 31, 2014. The analysis included 89 patients (74 male).

RESULTS

The median BMI was 30 kg/m2 (19-88.5). The median duration of the ECD support was 9.0 days, with a maximum of 37.1 days. The median LOS (length of stay) in the intensive care unit (ICU) was 21 days (range 0.06-197.6). The median hospital LOS was 34.9 days (range 0.1-213.8). VV ECMO was performed 72 times, and pECLA was performed 18 times. The number of patients successfully weaned off the ECD was 54 (60.6%). Survival at the discharge from the hospital was 48.3%.

CONCLUSIONS

54 (60.6%) patients were successfully weaned off the ECD; 43 (48.3%) patients survived and were discharged from the hospital. The analysis of correlations between BMI and outcomes of surgical patients treated with ECD showed no association between BMI and mortality. Complications (especially oxygenator clotting) were not more frequent in obese and extremely obese patients. We hypothesized that patients with higher or morbid BMIs would have increased mortality after ECD support. A BMI of 30.66 kg/m2 corresponded to the desired sensitivity and specificity to predict mortality. This finding applied only to the study group. Treatment with ECD in obese patients presents unique challenges, including percutaneous cannulation and increased staff requirements. However, based on these data, obesity should not be an exclusion criterion for ECD therapy.

A lard-rich high-fat diet increases hepatic peroxisome proliferator-activated receptors in endotoxemic rats

BACKGROUND

Diets high in saturated fatty acids activate chronic inflammation. We previously reported that, in even acute inflammation caused by lipopolysaccharide (LPS), liver injury was exacerbated in rats fed a lard-rich diet. Peroxisome proliferator-activated receptors (PPARs) are related to inflammation and are also key regulators of lipid metabolism. In this study, we examined effects of high-fat diet on liver injury and hepatic lipid metabolism during endotoxemia, measuring hepatic PPARs and other markers.

MATERIALS AND METHODS

Male Wistar rats were fed a high-fat diet (HFD, 60 kcal% fat) or control diet (CD, 10 kcal% fat) for 4 or 12 wk, injected with LPS and sacrificed at 0, 1.5, or 6 h. Analyses included plasma aspartate transaminase (AST) and alanine transaminase (ALT) levels, messenger RNA (mRNA) and protein levels of hepatic PPARα and PPARγ, and mRNA levels of enzymes related to fatty acid oxidation and synthesis.

RESULTS

Endotoxemic rats on HFD for 12 wk, but not 4 wk, had higher mRNA and protein levels for hepatic PPARs, than did those on CD (P < 0.01-0.05). Similarly, these rats had increased mRNA expression of hepatic fatty acid oxidation- and synthesis-related enzymes (P < 0.01-0.05). Rats injected with LPS had more severe liver injury, indicated by plasma AST/ALT, if on the HFD for 12 wk, compared with for 4 wk.

CONCLUSIONS

Consumption of a lard-rich diet for 12 wk worsened liver injury and increased hepatic PPARα and PPARγ expression in endotoxemic rats.

Impact of Norepinephrine Weight-Based Dosing Compared With Non–Weight-Based Dosing in Achieving Time to Goal Mean Arterial Pressure in Obese Patients With Septic Shock

Background: Currently, a lack of standardization exists in norepinephrine dosing units, the first-line vasopressor for septic shock. Timely achievement of goal mean arterial pressure (MAP) is dependent on optimal vasopressor dosing. Objective: To determine if weight-based dosing (WBD) of norepinephrine leads to earlier time to goal MAP compared with non-WBD in obese patients with septic shock. Methods: This was a retrospective, multicenter cohort study. Patients had a body mass index (BMI) ≥30 kg/m2 and received norepinephrine for septic shock with either a non-WBD strategy (between December 2009 and January 2013) or WBD strategy (between January 2013 and December 2015). The primary outcome was time to goal MAP. Secondary outcomes were norepinephrine duration, dose requirements, and development of treatment-related complications. Results: A total of 287 patients were included (WBD 144; non-WBD 143). There was no difference in median time to goal MAP (WBD 58 minutes, interquartile range [IQR] = 16.8-118.5, vs non-WBD 60 minutes, IQR = 17.5-193.5; P = 0.28). However, there was a difference in median cumulative norepinephrine dose (WBD 12.6 mg, IQR = 4.9-45.9, vs non-WBD 10.5 mg, IQR = 3.9-25.6; P = 0.04) and time to norepinephrine discontinuation (WBD 33 hours, IQR = 15-69, vs non-WBD 27 hours, IQR = 12-51; P = 0.03). There was no difference in rates of atrial fibrillation (WBD 15.3% vs non-WBD 23.7%; P = 0.07) or mortality (WBD 23.6% vs non-WBD 23.1%; P = 0.92). Conclusion: WBD of norepinephrine does not achieve time to goal MAP earlier in obese patients with septic shock. However, WBD may lead to higher norepinephrine cumulative dose requirements and prolonged time until norepinephrine discontinuation.

Patients with Risk Factors for Complications Do Not Require Longer Antimicrobial Therapy for Complicated Intra-Abdominal Infection

A prospective, multicenter, randomized controlled trial found that four days of antibiotics for source-controlled complicated intra-abdominal infection resulted in similar outcomes when compared with a longer duration. We hypothesized that patients with specific risk factors for complications also had similar outcomes. Short-course patients with obesity, diabetes, or Acute Physiology and Chronic Health Evaluation II ≥15 from the STOP-IT trial were compared with longer duration patients. Outcomes included incidence of and days to infectious complications, mortality, and length of stay. Obese and diabetic patients had similar incidences of and days to surgical site infection, recurrent intra-abdominal infection, extra-abdominal infection, and Clostridium difficile infection. Short- and long-course patients had similar incidences of complications among patients with Acute Physiology and Chronic Health Evaluation II ≥15. However, there were fewer days to the diagnosis of surgical site infection (9.5 ± 3.4 vs 21.6 ± 6.2, P = 0.010) and extra-abdominal infection (12.4 ± 6.9 vs 21.8 ± 6.1, P = 0.029) in the short-course group. Mortality and length of stay was similar for all groups. A short course of antibiotics in complicated intraabdominal infection with source control seems to have similar outcomes to a longer course in patients with diabetes, obesity, or increased severity of illness.

Obesity and Sepsis

Obesity has reached epidemic proportions over the last few decades. Obesity is associated with increased morbidity and mortality in hypertension, cardiovascular diseases, stroke, and cancer and is feared to decrease overall life expectancy over the next few decades. There is a growing body of evidence suggesting that obesity is a chronic inflammatory disease. Obesity is becoming a cause of concern in critically ill patients as well. Sepsis is the number one cause of morbidity and mortality in noncoronary artery disease critical care units all over the world and is associated with a high cost of care. An increase in morbidity in obese septic patients compared with lean people is a cause of growing concern. Laboratory evidence suggests that there is exaggeration in the inflammatory and prothrombogenic phenotype assumed by obese compared with lean septic animals. The exact mechanisms underlying this phenomenon are unknown. This article reviews some of the pathophysiological processes responsible for the underlying inflammation in obesity and sepsis and reviews the literature for the association of the two.

Impact of Obesity on Outcomes in a Multiethnic Cohort of Medical Intensive Care Unit Patients

PURPOSE

To examine the association of obesity with in-hospital mortality and complications during critical illness.

METHODS

We performed a retrospective analysis of a multiethnic cohort of 699 patients admitted to medical intensive care unit between January 2010 and May 2011 at Mount Sinai St. Luke's and Mount Sinai West Hospitals, tertiary care centers in New York City. Multivariate logistic regression analysis was used to evaluate the association between obesity (body mass index [BMI] ≥ 30] and in-hospital mortality. Subgroup analysis was performed in elderly patients (age ≥65 years).

RESULTS

Compared to normal BMI, obese patients had lower in-hospital mortality (24.4% vs 17.6%, P = .04). On multivariate analysis, obesity was independently associated with lower in-hospital mortality (odds ratio [OR]: 0.49, 95% confidence interval [CI]: 0.27-0.89, P = .018). There was no significant difference in rates of mechanical ventilation, reintubation, and vasopressor requirement across BMI categories. In subgroup analysis, elderly obese patients did not display lower in-hospital mortality (adjusted OR: 0.85, 95% CI: 0.40-1.82, P = .68).

CONCLUSION

Our study supports the hypothesis that obesity is associated with decreased mortality during critical illness. However, this finding was not observed among elderly obese patients. Further studies should explore the interaction between age, obesity, and outcomes in critical illness.

Managing social awkwardness when caring for morbidly obese patients in intensive care: A focused ethnography

BACKGROUND

Critically ill morbidly obese patients pose considerable healthcare delivery and resource utilisation challenges in the intensive care setting. These are resultant from specific physiological responses to critical illness in this population and the nature of the interventional therapies used in the intensive care environment. An additional challenge arises for this population when considering the social stigma that is attached to being obese. Intensive care staff therefore not only attend to the physical and care needs of the critically ill morbidly obese patient but also navigate, both personally and professionally, the social terrain of stigma when providing care.

AIM

To explore the culture and influences on doctors and nurses within the intensive care setting when caring for critically ill morbidly obese patients.

DESIGN AND METHODS

A focused ethnographic approach was adopted to elicit the 'situated' experiences of caring for critically ill morbidly obese patients from the perspectives of intensive care staff. Participant observation of care practices and interviews with intensive care staff were undertaken over a four month period. Analysis was conducted using constant comparison technique to compare incidents applicable to each theme.

SETTING

An 18 bedded tertiary intensive care unit in New Zealand.

PARTICIPANTS

Sixty-seven intensive care nurses and 13 intensive care doctors involved with the care and management of seven critically ill patients with a body mass index ≥40kg/m(2).

FINDINGS

Interactions between intensive care staff and morbidly obese patients were challenging due to the social stigma surrounding obesity. Social awkwardness and managing socially awkward moments were evident when caring for morbidly obese patients. Intensive care staff used strategies of face-work and mutual pretence to alleviate feelings of discomfort when engaged in aspects of care and caring. This was a strategy used to prevent embarrassment and distress for both the patients and staff.

CONCLUSIONS

This study has brought new understandings about intensive care situations where social awkwardness occurs in the context of obesity and care practices, and of the performances and behaviours of staff in managing the social awkwardness of fat-stigma during care situations.

Changes in Plasma Adiponectin Concentrations in Patients With Hemorrhagic Fever With Renal Syndrome: An Observational Prospective Study

The objective is to observe the changes in plasma adiponectin (APN) and its predictive capacity for disease severity and prognosis of hemorrhagic fever with renal syndrome (HFRS).One hundred and five patients who were treated at our center between October 2011 and December 2012 were randomly enrolled in this study. The patients were divided into a mild-type group, a moderate-type group, a severe-type group, and a critical-type group according to the HFRS criteria for clinical classification. Ninety-three plasma samples from the patients in the acute stage and 78 samples from the patients in the convalescent stage were obtained, and 28 samples from healthy subjects were obtained as controls. The concentrations of APN were detected using the enzyme-linked immunosorbent assay. The levels of white blood cells, platelets, hematocrit, albumin, blood urea nitrogen, serum creatinine, and uric acid in the samples were routinely tested. The levels of APN among the different types were compared; the correlation between APN and the laboratory parameters was analyzed. The predictive effectiveness for prognosis of APN and the laboratory parameters as mentioned above were evaluated using the receiver operating characteristic curve analysis.The levels of APN in the mild- and moderate-type patients in the acute stage were significantly higher than the severe-type and control (P < 0.05) and decreased with the severity of the disease, while there were no obvious difference among severe-, critical-type and control groups. The levels of APN in patients in the convalescent stage were higher than the control group (P < 0.05), and the APN levels of the critical-type group were higher compared with the mild-type groups (P < 0.05). Adiponectin was negatively correlated with white blood cells and hematocrit and positively correlated with platelets, albumin, and uric acid (P < 0.001). Adiponectin showed no statistical significance for predicting prognosis, with the area under the curve equal to 0.609 (95% CI: 0.237-0.745, P = 0.215).Adiponectin can be considered as a novel biomarker for disease severity in patients with HFRS, while it seems to have no predictive capacity for prognosis of HFRS.

Factors associated with length of stay in intensive care after bariatric surgery

BACKGROUND

Although uncommon, admission to the intensive care unit (ICU) after bariatric surgery may be necessary. This study evaluates characteristics of bariatric surgery patients that are admitted to the ICU, and identifies possible risk factors for increased ICU length of stay (LOS).

SETTING

Academic hospital, United States.

METHODS

A retrospective review of all ICU admissions after bariatric surgery from 2006 to 2013 was performed. Demographic characteristics and perioperative data were extracted, and risk factors for the LOS and mortality in the ICU were analyzed.

RESULTS

In total, 124 out of 4398 (2.8%) patients were admitted to the ICU after bariatric surgery. The mean age of these patients was 52.7±11.8 years and included 79 female patients (64%). There were 19 nonemergent or planned admissions (15.3%) and 105 unplanned admissions (84.7%). Mean body mass index was 47.8±12.2 kg/m², and mean American Society of Anesthesiology (ASA) score was 3.1±0.6. Roux-en-Y gastric bypass, sleeve gastrectomy, and adjustable gastric banding were performed in 80 (65%), 18 (15%), and 6 (5%) patients, respectively. Revisional procedures were performed in 15 (12%) patients. Respiratory failure was the most common cause for admission, occurring in 35 (28.2%) patients. The most common surgical complications requiring ICU admission were bleeding (n = 27) and anastomotic leak (n = 21). Mean ICU LOS was 6.0±9.6 (1-65) days. Mortality occurred in 5 (4.0%) patients. Based on univariate analysis, risk factors associated with ICU LOS were conversion from laparoscopic to open approach, anastomotic leak, time from operation to ICU admission, and reoperation. Higher ASA score was a significant risk factor for mortality.

CONCLUSION

ICU admission after bariatric surgery is uncommon but is associated with a significantly increased mortality. Anastomotic leak, conversions, time from operation to ICU admission, and reoperation have the greatest impact in determining the LOS in the ICU after bariatric surgery.

Adiponectin ameliorates endotoxin-induced acute cardiac injury

Background. Obesity is a risk factor for cardiovascular disease. Increasing evidence suggests that reduced levels of the adipocyte-derived plasma protein adiponectin are associated with an increased cardiovascular risk. Here, we examined the effects of adiponectin on lipopolysaccharide- (LPS-) induced acute cardiac injury in vivo. Methods and Results. A single dose of LPS (10 mg/kg) was intraperitoneally injected into wild-type (WT) and adiponectin-knockout (APN-KO) mice. Following LPS administration, APN-KO mice had exacerbation of left ventricular (LV) systolic dysfunction compared with WT mice. Administration of LPS to WT and APN-KO mice led to an increased expression of inflammatory cytokines including TNF-α and IL-6 in the heart, but the magnitude of this induction was greater in APN-KO mice compared to WT mice. Systemic delivery of an adenoviral vector expressing adiponectin (Ad-APN) improved LPS-induced LV dysfunction in APN-KO mice, and this effect was accompanied by the reduced expression of TNF-α and IL-6 in the heart. Administration of etanercept, a soluble TNF receptor abolished the reduced LV contractile function in response to LPS in APN-KO mice. Conclusion. These results suggest that adiponectin protects against LPS-induced acute cardiac injury by suppressing cardiac inflammatory responses, and could represent a potential therapeutic target in sepsis-associated myocardial dysfunction.

Obesity-induced hyperleptinemia improves survival and immune response in a murine model of sepsis

BACKGROUND

Obesity is a growing health problem and associated with immune dysfunction. Sepsis is defined as systemic inflammatory response syndrome that occurs during infection. Excessive inflammation combined with immune dysfunction can lead to multiorgan damage and death.

METHODS

The authors investigated the influence of a class 1 obesity (body mass index between 30 and 34.9) on immune function and outcome in sepsis and the role of leptin on the immune response. The authors used a long-term high-fat-diet feeding model (12 weeks) on C57Bl/6 mice (n = 100) and controls on standard diet (n = 140) followed by a polymicrobial sepsis induced by cecal ligation and puncture.

RESULTS

The authors show that class 1 obesity is connected to significant higher serum leptin levels (data are mean ± SEM) (5.7 ± 1.2 vs. 2.7 ± 0.2 ng/ml; n = 5; P = 0.033) and improved innate immune response followed by significant better survival rate in sepsis (71.4%, n = 10 vs. 10%, n = 14; P < 0.0001). Additional sepsis-induced increases in leptin levels stabilize body temperature and are associated with a controlled immune response in a time-dependent and protective manner. Furthermore, leptin treatment of normal-weight septic mice with relative hypoleptinemia (n = 35) also significantly stabilizes body temperature, improves cellular immune response, and reduces proinflammatory cytokine response resulting in improved survival (30%; n = 10).

CONCLUSIONS

Relative hyperleptinemia of class 1 obesity or induced by treatment is protective in sepsis. Leptin seems to play a regulatory role in the immune system in sepsis, and treatment of relative hypoleptinemia could offer a new way of an individual sepsis therapy.

The effect of obesity on outcomes in mechanically ventilated patients in a medical intensive care unit

BACKGROUND

The effect of obesity on outcomes in critically ill patients requiring invasive mechanical ventilation in a medical intensive care unit (ICU) is uncertain.

OBJECTIVES

This study was intended to further explore the relationship between outcomes and obesity in patients admitted to a medical ICU who required invasive mechanical ventilation.

METHODS

All adult patients admitted to the medical ICU at Washington Hospital Center requiring intubation and invasive mechanical ventilation for at least 24 h between January 1 and December 31, 2009, were retrospectively studied. Patients were categorized as nonobese (BMI <30) and obese (BMI ≥30). The primary outcome measure was 30-day mortality following intubation. Secondary outcomes included ICU length of stay (LOS), hospital LOS and duration of mechanical ventilation.

RESULTS

There were 504 eligible patients: 306 nonobese and 198 (39%) obese. Obese patients had significantly higher rates of diabetes (43 vs. 30%, p = 0.004), hyperlipidemia (32 vs. 24%, p = 0.04), asthma (16 vs. 8%, p = 0.004) and obstructive sleep apnea requiring continuous positive airway pressure treatment (12 vs. 1%, p < 0.001). Nonobese patients had a significantly higher rate of HIV infection (10 vs. 5%, p = 0.05) and malignancy (21 vs. 13%, p = 0.03). There were no significant differences in mortality up to 30 days following intubation and secondary outcomes between obese and nonobese patients. Multivariate analysis using logistic regression showed no significant relationship between mortality rate at 30 days following intubation and obesity. Outcomes were similar for the black obese (n = 153) and nonobese (n = 228) patients and the obese (n = 85) and very obese (n = 113) patients.

CONCLUSIONS

Obesity did not influence outcomes in critically ill patients requiring invasive mechanical ventilation in a medical ICU. Black obese patients had similar outcomes to black nonobese patients, and very obese patients also had similar outcomes to obese patients.

Outcomes of morbidly obese patients receiving invasive mechanical ventilation: a nationwide analysis

BACKGROUND

Critically ill, morbidly obese patients (BMI≥40 kg/m2) are at high risk of respiratory failure requiring invasive mechanical ventilation (IMV). It is not clear if outcomes of critically ill, obese patients are affected by obesity. Due to limited cardiopulmonary reserve, they may have poor outcomes. However, literature to this effect is limited and conflicted.

METHODS

We used the Nationwide Inpatient Sample from 2004 to 2008 to examine the outcomes of morbidly obese people receiving IMV and compared them to nonobese people. We identified hospitalizations requiring IMV and morbid obesity using International Classification of Diseases, 9th Revision, Clinical Modification codes. Primary outcomes studied were inhospital mortality, rates of prolonged mechanical ventilation (≥96 h), and tracheostomy. Multivariable logistic regression was used to adjust for potential confounding variables. We also examined outcomes stratified by number of organs failing.

RESULTS

Of all hospitalized, morbidly obese people, 2.9% underwent IMV. Mean age, comorbidity score, and severity of illness were lower in morbidly obese people. The adjusted mortality was not significantly different in morbidly obese people (OR 0.89; 95% CI, 0.74-1.06). When stratified by severity of disease, there was a stepwise increase in risk for mortality among morbidly obese people relative to nonobese people (range: OR, 0.77; 95% CI, 0.58-1.01 for only respiratory failure, to OR, 4.14; 95% CI, 1.11-15.3 for four or more organs failing). Rates of prolonged mechanical ventilation were similar, but rate of tracheostomy (OR 2.19; 95% CI, 1.77-2.69) was significantly higher in patients who were morbidly obese.

CONCLUSIONS

Morbidly obese people undergoing IMV have a similar risk for death as nonobese people if only respiratory failure is present. When more organs fail, morbidly obese people have increased risk for mortality compared with nonobese people.

Effect of morbid obesity on in-hospital mortality and coronary revascularization outcomes after acute myocardial infarction in the United States

The aim of this study was to investigate the impact of morbid obesity (body mass index ≥40 kg/m(2)) on in-hospital mortality and coronary revascularization outcomes in patients presenting with acute myocardial infarctions (AMI). The Nationwide Inpatient Sample of the Healthcare Cost and Utilization Project was used, and 413,673 patients hospitalized with AMIs in 2009 were reviewed. Morbidly obese patients constituted 3.7% of all patients with AMIs. Analysis of the unadjusted data revealed that morbidly obese patients compared with those not morbidly obese were more likely to undergo any invasive cardiac procedures when presenting with either ST-segment elevation myocardial infarction (97.4% vs 93.8%, p <0.0001) or non-ST-segment elevation myocardial infarction (85.5% vs 80.6%, p <0.0001). The unadjusted mortality rate for morbidly obese patients with AMIs was 3.5%, compared with 5.5% of those not obese (p <0.0001). After adjustment, lower odds of mortality in those morbidly obese compared to those not morbidly remained. In conclusion, patients with morbid obesity had lower odds of in-hospital mortality, compared to those not morbidly obese, consistent with the phenomenon of the "obesity paradox."

Systemic immune activation shapes stroke outcome

Stroke is a major cause of morbidity and mortality, and activation of the immune system can impact on stroke outcome. Although the majority of research has focused on the role of the immune system after stroke there is increasing evidence to suggest that inflammation and immune activation prior to brain injury can influence stroke risk and outcome. With the high prevalence of co-morbidities in the Western world such as obesity, hypertension and diabetes, pre-existing chronic 'low-grade' systemic inflammation has become a customary characteristic of stroke pathophysiology that needs to be considered in the search for new therapies. The importance of the immune system in stroke has been demonstrated in a number of ways, both experimentally and in the clinical setting. This review will focus on the effect of immune activation arising from systemic inflammatory conditions and infection, how it affects the incidence and outcomes of stroke, and the possible underlying mechanisms involved. This article is part of a Special Issue entitled 'Neuroinflammation in neurodegeneration and neurodysfunction'.

Clinical and critical care concerns in severely ill obese patient

The incidence of obesity has acquired an epidemic proportion throughout the globe. As a result, increasing number of obese patients is being presented to critical care units for various indications. The attending intensivist has to face numerous challenges during management of such patients. Almost all the organ systems are affected by the impact of obesity either directly or indirectly. The degree of obesity and its prolong duration are the main factors which determine the harmful effect of obesity on human body. The present article reviews few of the important clinical and critical care concerns in critically ill obese patients.

The association between body mass index, processes of care, and outcomes from mechanical ventilation: a prospective cohort study

OBJECTIVE

To determine the association between excess weight and processes of care and outcomes for critically ill adults.

DESIGN

Prospective cohort study.

SETTING

Three medical intensive care units at two hospitals.

PATIENTS

Five hundred eighty mechanically ventilated adult patients admitted between February 1, 2006 and January 31, 2008.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

After adjusting weight based on the recorded fluid balance before enrollment, 21.9% of subjects were categorized into different body mass index categories than without this adjustment. We used a competing risk analysis with events of interest considered death during hospitalization and successful liberation from mechanical ventilation. We found no statistically significant difference between body mass index categories (<25 kg/m² vs. 25 to <30 kg/m² vs. ≥30 kg/m²) in the competing risks analyses when the results were unadjusted or adjusted for severity of illness and comorbidities. When the analyses were adjusted for the use of continuous infusions of opioids and/or sedatives and ventilator parameters (tidal volume per ideal body weight, positive end-expiratory pressure, and airway pressure), subjects with an overweight fluid-balance-adjusted body mass index had significantly lower hazard ratios for dying while hospitalized (adjusted hazard ratio 0.68 [95% confidence interval 0.47-0.99], p=.044), and those with an obese fluid-adjusted body mass index had significantly higher hazard ratios for successful extubation (adjusted hazard ratio 1.53 [95% confidence interval 1.14-2.06], p=.005). An analysis of longer-term mortality found lower adjusted hazard ratios for subjects with overweight (adjusted hazard ratio 0.74 [95% confidence interval 0.56-0.96]) and obese (adjusted hazard ratio 0.74 [95% confidence interval 0.59-0.94]) fluid-balance-adjusted body mass indices.

CONCLUSIONS

Processes of provided care may affect the observed association between excess weight and outcomes for critically ill adults and should be considered when making inferences about observed results. It is unknown if disparities in processes of care are due to clinically justified reasons for variation, bias against heavier patients, or other reasons.

Obesity and respiratory infections: does excess adiposity weigh down host defense?

The number of overweight and obese individuals has dramatically increased in the US and other developed nations during the past 30 years. While type II diabetes and cardiovascular disease are well recognized co-morbid conditions associated with obesity, recent reports have demonstrated a greater severity of illness in obese patients due to influenza during the 2009 H1N1 pandemic. Consistent with these reports, diet-induced obesity has been shown to impair anti-viral host defense in murine models of influenza infection. However, the impact of obesity on the risk of community-acquired and nosocomial pneumonia in human patients is not clear. Relatively few studies have evaluated the influence of diet-induced obesity in murine models of bacterial infections of the respiratory tract. Obese leptin deficient humans and leptin and leptin-receptor deficient mice exhibit greater susceptibility to respiratory infections suggesting a requirement for leptin in the pulmonary innate and adaptive immune response to infection. In contrast to these studies, we have observed that obese leptin receptor signaling mutant mice are resistant to pneumococcal pneumonia highlighting the complex interaction between leptin receptor signaling and immune function. Given the increased prevalence of obesity and poor responsiveness of obese individuals to vaccination against influenza, the development of novel immunization strategies for this population is warranted. Additional clinical and animal studies are needed to clarify the relationship between increased adiposity and susceptibility to community-acquired and nosocomial pneumonia.

Leptin, adiponectin and pulmonary diseases

Adipose tissue produces leptin and adiponectin - energy-regulating adipokines that may also play a role in inflammatory pulmonary conditions, as suggested by some murine studies. Leptin and adiponectin and their respective receptors are expressed in the human lung. The association between systemic or airway leptin and asthma in humans is currently controversial, particularly among adults. The majority of the evidence among children however suggests that systemic leptin may be associated with greater asthma prevalence and severity, particularly among prepubertal boys and peripubertal/postpubertal girls. Systemic and airway leptin concentrations may also be disproportionately higher in chronic obstructive pulmonary disease (COPD) patients, particularly among women, and reflect greater airway inflammation and disease severity. Quite like leptin, the association between systemic and airway adiponectin and asthma in humans is also controversial. Some but not all studies, demonstrate that serum adiponectin concentrations are protective against asthma among premenopausal women and peripubertal girls. On the other hand, serum adiponectin concentrations are inversely associated with asthma severity among boys but positively associated among men. Further, systemic and airway adiponectin concentrations are higher in COPD patients than controls, as demonstrated by case-control studies of men. Systemic adiponectin is also positively associated with lung function in healthy adults but inversely associated with lung function in subjects with COPD. It is therefore possible that pro-inflammatory effects of adiponectin dominate under certain physiologic conditions and anti-inflammatory effects under others. The adipokine-lung disease literature has critical gaps that include a lack of adequately powered longitudinal or weight-intervention studies; inadequate adjustment for confounding effect of obesity; and unclear understanding of potential sex interactions. It is also uncertain whether adipokine derangements precede pulmonary disease or are a consequence of it. Future research will determine whether modulation of adipokines, independent of BMI, may allow novel ways to prevent or treat inflammatory pulmonary conditions.

Adiponectin-deficiency exaggerates sepsis-induced microvascular dysfunction in the mouse brain

Obesity increases circulating cell-endothelial cell interactions; an early marker of inflammation in laboratory model of sepsis, but little is known about the effect of different adipokines. Adiponectin is an anti-inflammatory adipokine secreted by adipocytes. Adiponectin deficiency is implicated in exaggerated proinflammatory phenotype in both obesity and sepsis via increased proinflammatory cytokine expression. However the effect of adiponectin deficiency on circulating cell-endothelial cell interactions in polymicrobial sepsis is unknown. Furthermore although brain dysfunction in septic patients is a known predictor of death, the pathophysiology involved is unknown. In the current study, we examined the effects of adiponectin deficiency on leukocyte (LA) and platelet adhesion (PA) in cerebral microcirculation of septic mice. Adiponectin deficient (Adipoq(-/-): Adko) and background strain C57Bl/6 (wild type (WT)) mice were used. Sepsis was induced using cecal ligation and puncture (CLP). We studied LA and PA in the cerebral microcirculation using intravital fluorescent video microscopy (IVM), blood brain barrier (BBB) dysfunction using Evans Blue (EB) leakage method and E-selectin expression using dual radiolabeling technique in different WT and Adko mice with CLP. Adiponectin deficiency significantly exaggerated LA (WT-CLP:201 ± 17; Adko-CLP: ± 53 cells/mm(2); P < 0.05) and PA (WT-CLP:125 ± 17; Adko-CLP:188 ± 20 cells/mm(2); P < 0.05) in cerebral microcirculation, EB leakage (WT-CLP:10 ± 3.7; Adko-CLP:24 ± 4.3 ng/g × µl plasma; P < 0.05) and E-selectin expression (WT-CLP:0.06 ± 0.11; Adko-CLP:0.44 ± 0.053 ng/g; P < 0.05) in the brain tissue of the mice with CLP. Furthermore, E-selectin monoclonal antibody (mAb) treatment attenuated cell adhesion and BBB dysfunction of Adko-CLP mice. Adiponectin deficiency is associated with exaggerated leukocyte and PA in cerebral microcirculation of mice with CLP via modulation of E-selectin expression.

Obese mice exhibit an altered behavioural and inflammatory response to lipopolysaccharide

Obesity is associated with an increase in the prevalence and severity of infections. Genetic animal models of obesity (ob/ob and db/db mice) display altered centrally-mediated sickness behaviour in response to acute inflammatory stimuli such as lipopolysaccharide (LPS). However, the effect of diet-induced obesity (DIO) on the anorectic and febrile response to LPS in mice is unknown. This study therefore determined how DIO and ob/ob mice respond to a systemic inflammatory challenge. C57BL/6 DIO and ob/ob mice, and their respective controls, were given an intraperitoneal (i.p.) injection of LPS. Compared with controls, DIO and ob/ob mice exhibited an altered febrile response to LPS (100 μg/kg) over 8 hours. LPS caused a greater and more prolonged anorexic effect in DIO compared with control mice and, in ob/ob mice, LPS induced a reduction in food intake and body weight earlier than it did in controls. These effects of LPS in obese mice were also seen after a fixed dose of LPS (5 μg). LPS (100 μg/kg) induced Fos protein expression in several brain nuclei of control mice, with fewer Fos-positive cells observed in the brains of obese mice. An altered inflammatory response to LPS was also observed in obese mice compared with controls: changes in cytokine expression and release were detected in the plasma, spleen, liver and peritoneal macrophages in obese mice. In summary, DIO and ob/ob mice displayed an altered behavioural response and cytokine release to systemic inflammatory challenge. These findings could help explain why obese humans show increased sensitivity to infections.

Extreme obesity and outcomes in critically ill patients

BACKGROUND

Recent literature suggests that obese critically ill patients do not have worse outcomes than patients who are normal weight. However, outcomes in extreme obesity (BMI ≥ 40 kg/m(2)) are unclear. We sought to determine the association between extreme obesity and ICU outcomes.

METHODS

We analyzed data from a multicenter international observational study of ICU nutrition practices that occurred in 355 ICUs in 33 countries from 2007 to 2009. Included patients were mechanically ventilated adults ≥ 18 years old who remained in the ICU for > 72 h. Using generalized estimating equations and Cox proportional hazard modeling with clustering by ICU and adjusting for potential confounders, we compared extremely obese to normal-weight patients in terms of duration of mechanical ventilation (DMV), ICU length of stay (LOS), hospital LOS, and 60-day mortality.

RESULTS

Of the 8,813 patients included in this analysis, 3,490 were normal weight (BMI 18.5-24.9 kg/m(2)), 348 had BMI 40 to 49.9 kg/m(2), 118 had BMI 50 to 59.9 kg/m(2), and 58 had BMI ≥ 60 kg/m(2). Unadjusted analyses suggested that extremely obese critically ill patients have improved mortality (OR for death, 0.77; 95% CI, 0.62-0.94), but this association was not significant after adjustment for confounders. However, an adjusted analysis of survivors found that extremely obese patients have a longer DMV and ICU LOS, with the most obese patients (BMI ≥ 60 kg/m(2)) also having longer hospital LOS.

CONCLUSIONS

During critical illness, extreme obesity is not associated with a worse survival advantage compared with normal weight. However, among survivors, BMI ≥ 40 kg/m(2) is associated with longer time on mechanical ventilation and in the ICU. These results may have prognostic implications for extremely obese critically ill patients.