Obesity in the Intensive Care Unit

Prevalence and risk factors of myocardial and acute kidney injury following radical nephrectomy with vena cava thrombectomy: a retrospective cohort study

BACKGROUND

Radical nephrectomy with thrombectomy is the mainstay treatment for patients with renal cell carcinoma with vena cava thrombus. But the procedure is full of challenge, with high incidence of major complications and mortality. Herein, we investigated the incidence and predictors of myocardial injury and acute kidney injury (AKI) in patients following radical nephrectomy with inferior vena cava thrombectomy.

METHODS

Patients who underwent nephrectomy with thrombectomy between January 2012 and June 2020 were retrospectively reviewed. Myocardial injury was diagnosed when peak cardiac troponin I was higher than 0.03 ng/ml. AKI was diagnosed according to the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Multivariable logistic regression models were used to identify predictors of myocardial injury or AKI after surgery.

RESULTS

A total of 143 patients were included in the final analysis. Myocardial injury and AKI occurred in 37.8 and 42.7% of patients after this surgery, respectively. Male sex (odds ratio [OR] 0.27, 95% confidence interval [CI] 0.10-0.71; P = 0.008) was associated with a lower risk, whereas high level Mayo classification (compared with Mayo level I + II, Mayo level III + IV: OR 4.21, 95% CI 1.42-12.4; P = 0.009), acute normovolemic hemodilution before surgery (OR 2.66, 95% CI 1.10-6.41; P = 0.029), long duration of intraoperative tachycardia (per 20 min: OR 1.49, 95% CI 1.10-2.16; P = 0.036), and long duration of surgery (per 1 h, OR 1.48, 95% CI 1.03-2.16, P = 0.009) were associated with a higher risk of myocardial injury. High body mass index (OR 1.18, 95% CI 1.06-1.33; P = 0.004) and long duration of intraoperative hypotension (per 20 min: OR 1.30, 95% CI 1.04-1.64; P = 0.024) were associated with a higher risk, whereas selective renal artery embolism before surgery (OR 0.20, 95% CI 0.07-0.59, P = 0.004) was associated with a lower risk of AKI.

CONCLUSION

Myocardial injury and AKI were common in patients recovering from radical nephrectomy with inferior vena cava thrombectomy. Whether interventions targeting the above modifiable factors can improve outcomes require further studies.

Morbidity and Mortality in the Obese Trauma Intensive Care Unit Patient

INTRODUCTION

Obesity is an epidemic in the United States, known to be associated with comorbidities. However, some data show that obesity may be a protective factor in some instances. The purpose of this study is to determine if there are differences in morbidity and mortality when comparing the obese and non-obese critically ill trauma patient populations.

MATERIALS AND METHODS

This was a retrospective study conducted at Prisma Health Upstate in Greenville, South Carolina, an Adult Level 1 Trauma Center. Patients over the age of 18 years admitted due to trauma from February 6, 2016 to February 28, 2019 were included in this study. Burn patients were excluded. An online trauma database was used to obtain age, sex, body mass index, Glasgow coma score (GCS), injury severity score (ISS), revised trauma score (RTS), days on mechanical ventilation, hospital length of stay (LOS), and intensive care unit (ICU) LOS.

RESULTS

There were 2365 critically ill trauma patients who met inclusion criteria for this study. 1570 patients were men (66.38%) and mean age was 53.2 ± 20.9. Of the patients, 2166 patients had blunt trauma (91.59%). Median GCS was 15 (interquartilerange [IQR]: 12, 15), median RTS was 12 (IQR: 11, 12), and median ISS was 17 (IQR: 9, 22). Obese critically ill trauma patients had significantly lower odds of mortality than nonobese (OR .686, CI 0.473-.977). Penetrating traumas (OR: 4.206, CI: 2.478, 6.990), increased ISS (OR: 1.095, CI: .473, 1.112), and increased age (OR: 1.036, CI: 1.038, 1.045) were associated with significantly increased odds of mortality.

DISCUSSION

The obesity paradox is observed in the obese critically ill trauma patient population.

Evaluation of ebselen in resolving a methicillin-resistant Staphylococcus aureus infection of pressure ulcers in obese and diabetic mice

Pressure ulcers (PUs) are a source of morbidity in individuals with restricted mobility including individuals that are obese or diabetic. Infection of PUs with pathogens, including methicillin-resistant Staphylococcus aureus (MRSA), impairs ulcers from healing. The present study evaluated ebselen as a topical antibacterial to treat MRSA-infected PUs. Against two different S. aureus strains, including MRSA USA300, resistance to ebselen did not emerge after 14 consecutive passages. Resistance to mupirocin emerged after only five passages. Additionally, ebselen was found to exert a modest postantibiotic effect of five hours against two MRSA strains. Ebselen was subsequently evaluated in MRSA-infected PUs in two models using obese and diabetic mice. In obese mice, topical ebselen (89.2% reduction) and oral linezolid (84.5% reduction) similarly reduced the burden of MRSA in infected PUs. However, in diabetic mice, topical ebselen (45.8% reduction in MRSA burden) was less effective. Histopathological evaluation of ulcers in diabetic mice determined that ebselen treatment resulted in fewer bacterial colonies deep within the dermis and that the treatment exhibited evidence of epithelial regeneration. Topical mupirocin was superior to ebselen in reducing MRSA burden in infected PUs both in obese (98.7% reduction) and diabetic (99.3% reduction) mice. Ebselen’s antibacterial activity was negatively impacted as the bacterial inoculum was increased from 10⁵ CFU/mL to 10⁷ CFU/mL. These results suggest that a higher dose of ebselen, or a longer course of treatment, may be needed to achieve a similar effect as mupirocin in topically treating MRSA-infected pressure ulcers.

Does Weight Matter? Outcomes in Adult Patients on Venovenous Extracorporeal Membrane Oxygenation When Stratified by Obesity Class

BACKGROUND

Many believe obesity is associated with higher rates of mortality in the critically ill. The purpose of this retrospective observational study is to evaluate the association between body mass index (BMI) and survival in patients receiving venovenous (VV) extracorporeal membrane oxygenation (ECMO) for acute hypoxic or hypercarbic respiratory failure.

METHODS

All of the patients admitted to a dedicated VV ECMO unit were included. Patients <18 years of age, listed for lung transplant, or underweight were excluded. ECMO outcomes, including hospital length of stay and survival to discharge, were analyzed after stratification according to BMI. Multivariate logistic and linear regression techniques were used to assess variables associated with the outcomes of death and length of stay, respectively.

RESULTS

One hundred ninety-four patients with a median BMI of 35.7 kg/m (33-42 kg/m) were included. Obese patients were older, had higher creatinine levels, and required higher levels of positive end-expiratory pressure and mean airway pressure at time of cannulation. Survival to discharge in any group did not differ when stratified by BMI classification (P = .36). Multivariable regression did not reveal any association with greater odds of death or longer length of stay when controlling for BMI and other variables.

CONCLUSIONS

We did not detect an association between obesity and increased mortality in patients requiring VV ECMO for acute hypoxic or hypercarbic respiratory failure. These data suggest that obesity alone should not exclude candidacy for VV ECMO. Evidence for the "obesity paradox" in this population of VV ECMO patients may be supported by these data.

Establishing failure predictors for the planned extubation of overweight and obese patients

We investigated failure predictors for the planned extubation of overweight (body mass index [BMI] = 25.0–29.9) and obese (BMI ≥ 30) patients. All patients admitted to the adult intensive care unit (ICU) of a tertiary hospital in Taiwan were identified. They had all undergone endotracheal intubation for > 48 h and were candidates for extubation. During the study, 595 patients (overweight = 458 [77%]); obese = 137 [23%]) with planned extubation after weaning were included in the analysis; extubation failed in 34 patients (5.7%). Their mean BMI was 28.5 ± 3.8. Only BMI and age were significantly different between overweight and obese patients. The mortality rate for ICU patients was 0.8%, and 2.9% for inpatients during days 1–28; the overall in-hospital mortality rate was 8.4%. Failed Extubation group patients were significantly older, had more end-stage renal disease (ESRD), more cardiovascular system-related respiratory failure, higher maximal inspiratory pressure (MIP), lower maximal expiratory pressure (MEP), higher blood urea nitrogen, and higher ICU- and 28-day mortality rates than did the Successful Extubation group. Multivariate logistic regression showed that cardiovascular-related respiratory failure (odds ratio [OR]: 2.60; 95% [confidence interval] CI: 1.16–5.80), ESRD (OR: 14.00; 95% CI: 6.25–31.35), and MIP levels (OR: 0.94; 95% CI: 0.90–0.97) were associated with extubation failure. We conclude that the extubation failure risk in overweight and obese patients was associated with cardiovascular system-related respiratory failure, ESRD, and low MIP levels.

Being Overweight Is Associated With Greater Survival in ICU Patients: Results From the Intensive Care Over Nations Audit

OBJECTIVE

To assess the effect of body mass index on ICU outcome and on the development of ICU-acquired infection.

DESIGN

A substudy of the Intensive Care Over Nations audit.

SETTING

Seven hundred thirty ICUs in 84 countries.

PATIENTS

All adult ICU patients admitted between May 8 and 18, 2012, except those admitted for less than 24 hours for routine postoperative monitoring (n = 10,069). In this subanalysis, only patients with complete data on height and weight (measured or estimated) on ICU admission in order to calculate the body mass index were included (n = 8,829).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Underweight was defined as body mass index less than 18.5 kg/m, normal weight as body mass index 18.5-24.9 kg/m, overweight as body mass index 25-29.9 kg/m, obese as body mass index 30-39.9 kg/m, and morbidly obese as body mass index greater than or equal to 40 kg/m. The mean body mass index was 26.4 ± 6.5 kg/m. The ICU length of stay was similar among categories, but overweight and obese patients had longer hospital lengths of stay than patients with normal body mass index (10 [interquartile range, 5-21] and 11 [5-21] vs 9 [4-19] d; p < 0.01 pairwise). ICU mortality was lower in morbidly obese than in normal body mass index patients (11.2% vs 16.6%; p = 0.015). In-hospital mortality was lower in morbidly obese and overweight patients and higher in underweight patients than in those with normal body mass index. In a multilevel Cox proportional hazard analysis, underweight was independently associated with a higher hazard of 60-day in-hospital death (hazard ratio, 1.32; 95% CI, 1.05-1.65; p = 0.018), whereas overweight was associated with a lower hazard (hazard ratio, 0.79; 95% CI, 0.71-0.89; p < 0.001). No body mass index category was associated with an increased hazard of ICU-acquired infection.

CONCLUSIONS

In this large cohort of critically ill patients, underweight was independently associated with a higher hazard of 60-day in-hospital death and overweight with a lower hazard. None of the body mass index categories as independently associated with an increased hazard of infection during the ICU stay.

Physiological and management implications of obesity in critical illness

Obesity is highly prevalent in the United States and is becoming increasingly common worldwide. The anatomic and physiological changes that occur in obese individuals may have an impact across the spectrum of critical illness. Obese patients may be more susceptible to hypoxemia and hypercapnia. During mechanical ventilation, elevated end-expiratory pressures may be required to improve lung compliance and to prevent ventilation-perfusion mismatch due to distal airway collapse. Several studies have shown an increased risk of organ dysfunction such as the acute respiratory distress syndrome and acute kidney injury in obese patients. Predisposition to ventricular hypertrophy and increases in blood volume should be considered in fluid management decisions. Obese patients have accelerated muscle losses in critical illness, making nutrition essential, although the optimal predictive equation to estimate nutritional needs or formulation for obese patients is not well established. Many common intensive care unit medications are not well studied in obese patients, necessitating understanding of pharmacokinetic concepts and consultation with pharmacists. Obesity is associated with higher risk of deep venous thrombosis and catheter-associated bloodstream infections, likely related to greater average catheter dwell times. Logistical issues such as blood pressure cuff sizing, ultrasound assistance for procedures, diminished quality of some imaging modalities, and capabilities of hospital equipment such as beds and lifts are important considerations. Despite the physiological alterations and logistical challenges involved, it is not clear whether obesity has an effect on mortality or long-term outcomes from critical illness. Effects may vary by type of critical illness, obesity severity, and obesity-associated comorbidities.

Body mass index and pressure ulcers: improved predictability of pressure ulcers in intensive care patients

BACKGROUND

Obesity contributes to immobility and subsequent pressure on skin surfaces. Knowledge of the relationship between obesity and development of pressure ulcers in intensive care patients will provide better understanding of which patients are at high risk for pressure ulcers and allow more efficient prevention.

OBJECTIVES

To examine the incidence of pressure ulcers in patients who differ in body mass index and to determine whether inclusion of body mass index enhanced use of the Braden scale in the prediction of pressure ulcers.

METHODS

In this retrospective cohort study, data were collected from the medical records of 4 groups of patients with different body mass index values: underweight, normal weight, obese, and extremely obese. Data included patients' demographics, body weight, score on the Braden scale, and occurrence of pressure ulcers.

RESULTS

The incidence of pressure ulcers in the underweight, normal weight, obese, and extremely obese groups was 8.6%, 5.5%, 2.8%, and 9.9%, respectively. When both the score on the Braden scale and the body mass index were predictive of pressure ulcers, extremely obese patients were about 2 times more likely to experience an ulcer than were normal weight patients. In the final model, the area under the curve was 0.71. The baseline area under the curve for the Braden scale was 0.68.

CONCLUSIONS

Body mass index and incidence of pressure ulcers were related in intensive care patients. Addition of body mass index did not appreciably improve the accuracy of the Braden scale for predicting pressure ulcers.

Computed tomography-defined abdominal adiposity is associated with acute kidney injury in critically ill trauma patients*

OBJECTIVES

Higher body mass index is associated with increased risk of acute kidney injury after major trauma. Since body mass index is nonspecific, reflecting lean, fluid, and adipose mass, we evaluated the use of CT to determine if abdominal adiposity underlies the body mass index-acute kidney injury association.

DESIGN

Prospective cohort study.

SETTING

Level I Trauma Center of a university hospital.

PATIENTS

Patients older than 13 years with an Injury Severity Score greater than or equal to 16 admitted to the trauma ICU were followed for development of acute kidney injury over 5 days. Those with isolated severe head injury or on chronic dialysis were excluded.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Clinical, anthropometric, and demographic variables were collected prospectively. CT images at the level of the L4-5 intervertebral disc space were extracted from the medical record and used by two operators to quantitate visceral adipose tissue and subcutaneous adipose tissue areas. Acute kidney injury was defined by Acute Kidney Injury Network creatinine and dialysis criteria. Of 400 subjects, 327 (81.8%) had CT scans suitable for analysis: 264 of 285 (92.6%) blunt trauma subjects and 63 of 115 (54.8%) penetrating trauma subjects. Visceral adipose tissue and subcutaneous adipose tissue areas were highly correlated between operators (intraclass correlation > 0.99, p < 0.001 for each) and within operator (intraclass correlation > 0.99, p < 0.001 for each). In multivariable analysis, the standardized risk of acute kidney injury was 15.1% (95% CI, 10.6-19.6%), 18.1% (14-22.2%), and 23.1% (18.3-27.9%) at the 25th, 50th, and 75th percentiles of visceral adipose tissue area, respectively (p = 0.001), with similar findings when using subcutaneous adipose tissue area as the adiposity measure.

CONCLUSIONS

Quantitation of abdominal adiposity using CT scans obtained for clinical reasons is feasible and highly reliable in critically ill trauma patients. Abdominal adiposity is independently associated with acute kidney injury in this population, confirming that excess adipose tissue contributes to the body mass index-acute kidney injury association. Further studies of the potential mechanisms linking adiposity with acute kidney injury are warranted.

Nutrition and care considerations in the overweight and obese population within the critical care setting

Nutrition and care considerations in the overweight and obese population within the critical care setting are multifaceted. Patients requiring critical care have specialized care management needs that often times challenge health care providers. When patients are obese, this further complicates the physiologic aspects of healing, thus creating challenges to meeting both the nutritional needs of the individual and hampering treatment. This article reviews the care considerations, physiology of bariatric patients, and challenges of providing safe and quality care, including current evidence-based practice strategies developed to provide optimal support for obese patients during hospitalization and within the critical care setting.

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.

The effect of body mass index on intubation success rates and complications during emergency airway management

We evaluated the effect of body mass index (BMI) on intubation success rates and complications during emergency airway management. We retrospectively analyzed an airway registry at an academic medical center. The primary outcomes were the incidence of difficult intubation and complication rates, stratified by BMI. We captured 1,075 (98 %, 1,075/1,102; 95 % CI 97-99) intubations. Four hundred twenty-six patients (40 %) had a normal BMI, 289 (27 %) were overweight, 261 (25 %) were obese, and 77 (7 %) were morbidly obese. In a multivariate analysis, obesity (OR 1.90; 95 % CI 1.04-3.45; p = 0.04), but not morbid obesity (OR 2.18; 95 % CI 0.95-4.99; p = 0.07), predicted difficult intubation. BMI was not predictive of post-intubation complications. Airway management in the morbidly obese differed when compared with lean patients, with less use of rapid sequence intubation and increased use of fiberoptic bronchoscopy in the former. During emergency airway management, difficult intubation is more common in obese patients, and morbidly obese patients are more commonly treated as potentially difficult airways.

African American race, obesity, and blood product transfusion are risk factors for acute kidney injury in critically ill trauma patients

PURPOSE

Acute kidney injury (AKI) is a common source of morbidity after trauma. We sought to determine novel risk factors for AKI, by Acute Kidney Injury Network (AKIN) criteria, in critically ill trauma patients.

MATERIALS AND METHODS

A prospective cohort of 400 patients admitted to the intensive care unit of a level 1 trauma center was followed for the development of AKI over 5 days.

RESULTS

Acute kidney injury developed in 147 (36.8%) of 400 patients. In multivariable regression analysis, independent risk factors for AKI included African American race (odds ratio [OR], 1.86; 95% confidence interval [CI], 1.08-3.18; P = .024), body mass index of 30 kg/m(2) or greater (OR, 4.72 versus normal body mass index; 95% CI, 2.59-8.61; P < .001), diabetes mellitus (OR, 3.26; 95% CI, 1.30-8.20; P = .012), abdominal Abbreviated Injury Scale score of 4 or more (OR, 3.78; 95% CI, 1.79-7.96; P < .001), and unmatched packed red blood cells administered during resuscitation (OR, 1.13 per unit; 95% CI, 1.04-1.23; P = .004). Acute Kidney Injury Network stages 1, 2, and 3 were associated with hospital mortality rates of 9.8%, 13.7%, and 30.4%, respectively, compared with 3.8% for those without AKI (P < .001).

CONCLUSIONS

Acute kidney injury in critically ill trauma patients is associated with substantial mortality. The findings of African American race, obesity, and blood product administration as independent risk factors for AKI deserve further study to elucidate underlying mechanisms.

Nutritional support of the obese and critically ill obese patient

With the dramatic increase in the prevalence of obesity worldwide and in the United States, it is virtually certain that clinicians will be caring for bariatric and obese nonbariatric patients in increasing numbers. This patient population presents several difficulties from the medical and surgical management perspectives. In particular, nutrition of the bariatric patient and critically ill obese patient is challenging. A clear understanding of the nutritional assessment and unique management strategies available for the bariatric and the critically ill obese patient is essential to provide them with the safest and most effective care.

Pharmacokinetic evaluation of fluconazole in critically ill patients

INTRODUCTION

Invasive candidiasis has emerged over the last few decades as an increasingly important nosocomial problem for the critically ill, affecting around 2% of intensive care unit patients. Although poor outcomes associated with invasive candidiasis among critically ill patients may relate to severe underlying disease processes and delayed institution of antifungal therapy, inadequate dosing of antifungal agents may also contribute.

AREAS COVERED

This drug evaluation provides a critical appraisal of the published literature pertaining to the pharmacokinetics of fluconazole in critically ill, obese or severely burned patients, including those receiving acute renal replacement therapy. The pharmacodynamics of fluconazole is also covered, as well as the likely clinical implications for optimal dosing and the toxicity of fluconazole. Last, variations in fluconazole susceptibility patterns of Candida spp. are also discussed.

EXPERT OPINION

Recently, there has been an increased but geographically variable prevalence of non-albicans Candida spp., causing invasive candidiasis and an overall trend towards reduced fluconazole susceptibility. The pathophysiological changes of critical illness, coupled with a lack of dose finding studies, support the use of local susceptibility patterns to guide fluconazole dosing until such time as pharmacokinetic-pharmacodynamic information to guide optimal fluconazole dosing strategies and pharmacodynamic targets becomes available.

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.

Implications of obesity for drug therapy: limitations and challenges

Obesity has become a worldwide challenge with significant health and socioeconomic implications. One of the major implications is its impact on drug therapy. In order to gain a better understanding of this impact, we surveyed the regulatory guidances, the newly approved molecular entity drug products, and drug product labels in the Physician's Desk Reference. This review summarizes the findings of the survey along with the existing knowledge on pharmacokinetic and pharmacodynamic changes associated with obesity.

Difficulties in managing the surgical patient who is morbidly obese

Managing patients who are morbidly obese in the intensive care unit is associated with a variety of problems uncommonly experienced with the those who are not morbidly obese. Clinicians experience a myriad of unique problems and circumstances, from the need for special beds and lifts to unusual and unknown volumes of distribution resulting in unclear drug dosing. This review examines several issues including sedation, invasive monitoring, venous thromboembolism prophylaxis, surgical infections, nutritional support, and other complications that may be of particular importance to the critically ill patient who is morbidly obese. In many cases, care is altered based on the complicating issues surrounding morbid obesity. In other cases, the presence of obesity suggests no alterations in our routine critical care delivery. A comprehensive review of the literature is undertaken, data are critically considered, and overall opinion is rendered based on the available peer-reviewed literature. In many cases, data are not available that address the specific patient population in question, so related papers (like gastric bypass data) are considered. Many issues do not have definitive answers based on randomized controlled trials, and much is left to treating clinician opinion and local practice patterns. Where good data exist, however, one should consider carefully and individually deviation from the evidence-based approach.

Metabolic support of the obese intensive care unit patient: a current perspective

PURPOSE OF REVIEW

Obesity is a widespread condition associated with a variety of mechanical, metabolic, and physiologic changes that affect both health outcomes and delivery of care. Nutrition support is a key element of management during critical illness known to improve outcomes favorably, but is likewise complicated in the presence of obesity. This review serves to discuss the challenges unique to management of critically ill obese patients and an evidence-based approach to nutrition support in this patient population.

RECENT FINDINGS

High-protein, hypocaloric feeding has emerged as a nutrition support strategy capable of reducing hyperglycemia and protein catabolism, while promoting favorable changes in body composition and fluid mobilization. Recent data have shown a protective effect of mild-moderate obesity (BMI 30-39.9 kg/m2), with improved morbidity and mortality outcomes in this subgroup. Therefore, it is unclear whether hypocaloric feeding represents an inferior approach in this subgroup in which weight maintenance may be preferable.

SUMMARY

There are many obstacles that limit provision of nutrition support in the obese ICU patient. Calculating energy needs accurately is extremely problematic due to a lack of reliable prediction equations and a wide variability in body composition among the obese patients. Further research is needed to determine a better approach to estimating energy needs in this population, in addition to validating hypocaloric feeding as the standard approach to nutrition support in the obese patients.