Morbid Obesity in the Medical ICU

doi:10.1378/chest.120.6.1989

Chest

Volume 120, Issue 6, December 2001, Pages 1989-1997

https://doi.org/10.1378/chest.120.6.1989 Get rights and content

Study objective

To describe the clinical course, complications, and prognostic factors of morbidly obese patients admitted to the ICU compared to a control group of nonobese patients.

Design

A retrospective study.

Setting

Two university-affiliated hospitals.

Methods

We reviewed the medical records of 117 morbidly obese patients (body mass index ≥ 40 kg/m²) admitted to the medical ICU between January 1994 and June 2000. Data collected included demographic information, comorbid condition, APACHE (acute physiology and chronic health evaluation) II score, invasive procedures, organ failure, and in-hospital mortality.

Results

Obstructive airway disease, pneumonia, and sepsis were the main reasons for admission to the ICU in the morbidly obese group. Sixty-one percent of the morbidly obese patients and 46% of the nonobese group required mechanical ventilation (p = 0.02). The mean lengths of mechanical ventilation and ICU stay were significantly longer for the morbidly obese group (7.7 ± 9.6 days and 9.3 ± 10.5 days vs 4.6 ± 7.1 days and 5.8 ± 8.2 days, respectively; p < 0.001). APACHE II scores were not significantly different in the two groups (19.1 ± 7.6 and 20.6 ± 12.2; p = 0.6). Overall mortality was 30% for the morbidly obese patients and 17% for the nonobese group (p = 0.019). By multivariate analysis, multiorgan failure (odds ratio [OR], 4.6; 95% confidence interval [CI], 2.1 to 16.6), Pao₂/fraction of inspired oxygen < 200 for > 48 h (OR, 2.3; 95% CI, 1.2 to 7.8), and depressed left ventricular ejection fraction < 40% (OR, 1.4; 95% CI, 1.03 to 13.8) were independently associated with ICU mortality in the morbidly obese group.

Conclusion

We conclude that critically ill morbidly obese patients are at increased risk of morbidity and mortality compared to the nonobese patients.

Section snippets

Patients

After obtaining Institutional Review Board approval from the University at Buffalo, we have reviewed the medical records of all hospitalized morbidly obese adults patients admitted to the medical ICUs of two university affiliated hospitals. Both hospitals (Erie County Medical Center and the Buffalo General Hospital) are tertiary-care centers with separate medical and surgical ICUs managed by house-staff and critical-care attending physicians. The degree of obesity was assessed by the body mass

Demographic Characteristics

There were 132 critically ill morbidly obese patients admitted to the ICU of 9,727 ICU admissions between January 1994 and June 2000. Three patients remained in the ICU for < 24 h, and 12 patients had more than one hospital admission, leaving 117 patients eligible for analysis. Nine of 117 (8%) patients were transferred from the medical wards of the same hospital, and 108 patients (92%) were admitted from the emergency department. In the nonobese group, 14 patients (11%) were in-hospital

Discussion

This study, one of the largest unicenter studies, including 117 consecutive hospitalized patients, provides a comprehensive insight about the morbidity and mortality of the critically ill morbidly obese patients in the ICU. The main findings were as follows: (1) critically ill morbidly obese patients have higher ICU mortality compared to nonobese patients, (2) morbidly obesity is associated with prolonged mechanical ventilation and extended “weaning” period, (3) MOF remains the best predictor

References (36)

FX Pi-Sunyer
Health implications of obesity
Am J Clin Nutr
(1991)
GA Colditz
Economic costs of obesity
Am J Clin Nutr
(1992)
P Marik et al.
The obese patient in the ICU
Chest
(1998)
JP Adams et al.
Obesity in anesthesia and intensive care
Br J Anaesth
(2000)
RC Bone et al.
ACCP/SCCM consensus conference: definitions for sepsis and organ failure and guidelines for the use of innovative therapies in sepsis
Chest
(1992)
RC Bone et al.
An early test of survival in patients with the adult respiratory distress syndrome, the Pa o₂/Fio₂ ratio and its differential response to conventional therapy
Chest
(1989)
FX Pi-Sunyer
Medical hazards of obesity
Ann Intern Med
(1993)
RJ Kuczmarski et al.
Increasing prevalence of overweight among US adults: The National Health and Nutrition Examination Surveys, 1960 to 1991
JAMA
(1994)
Update: prevalence of overweight among children, adolescents and adults–United States 1988–1994
MMWR Morb Mortal Wkly Rep
(1997)
TB VanItalie
Prevalence of obesity
Endocrinol Metab Clin North Am
(1996)

JP Kress et al.

Outcomes of critically ill patients denied consideration for liver transplantation

Am J Respir Crit Care Med

(2000)

GR Bernard et al.

The American-European Consensus Conference on ARDS: definitions, mechanisms, relevant outcomes, and clinical trial coordination

Am J Respir Crit Care Med

(1994)

J Cohen

A coefficient of agreement for nominal scales

Educ Psychol Meas

(1960)

BK Slinker et al.

Multiple regression for physiological data analysis: the problem of multicollinearity

Am J Physiol

(1985)

EE Calle et al.

Body-mass index and mortality in a prospective cohort of U.S. adults

N Engl J Med

(1999)

P Diehr et al.

Body mass index and mortality in nonsmoking older adults: The Cardiovascular Health Study

Am J Public Health

(1998)

IM Lee et al.

Body weight and mortality: a 27-year follow up of middle age men

JAMA

(1993)

P Smith-Choban et al.

Obesity and increased mortality in blunt trauma

J Trauma

(1991)

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Patients admitted to an intensive care unit (ICU) frequently suffer from multiple chronic diseases, including obstructive sleep apnea (OSA). Until recently OSA was not considered as a key determinant in an ICU patient's prognosis. The objective of this study was to document the impact of OSA on the prognosis of ICU patients.
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Obesity hypoventilation syndrome (OHS) is a severe complication of obesity. OHS patients may present with acute hypercapnic respiratory failure (AHRF), necessitating intensive care unit (ICU) admission for monitoring and treatment. Unfortunately, OHS remains underrecognized as a cause of AHRF. Prompt treatment of these patients with noninvasive ventilation improves blood gases and lung mechanics, decreases the need for invasive mechanical ventilation, and may reduce hospital stay and morbidity. The management of mechanical ventilation in obese patients with respiratory failure is one of the most challenging problems facing the treating physician. In this chapter, we address the issues surrounding OHS in the ICU setting, including the pathophysiology, clinical characteristics, and contemporary management of this serious medical problem.
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As a result of the constantly increasing epidemic of obesity, it has become a common problem in the intensive care unit. Morbid obesity has numerous consequences for the respiratory system. It affects both respiratory mechanics and pulmonary gas exchange, and dramatically impacts on the patient's management and outcome. With the potential for causing devastating respiratory complications, the particular anatomical and physiological characteristics of the respiratory system of the morbidly obese subject should be carefully taken into consideration. The present article reviews the management of obese patients in respiratory failure, from noninvasive ventilation to tracheostomy, including postural and technical issues, and explains the physiologically based ventilatory strategy both for NIV and invasive mechanical ventilation up to the weaning from the ventilatory support.
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Obesity poses a challenge to landmark identification complicating basic resuscitative procedures like the placement of an airway or intravenous lines and has adverse physiologic changes such as hyperglycemia [7]. There is evidence to suggest that this translates into worse outcomes for obese patients in Intensive Care Units (ICUs) [8-14]. On the contrary, there is growing data supporting a protective effect of obesity in critically ill patients.
During critical illness, obese patients have better outcomes compared to patients with normal BMI, and this is known as the obesity paradox. The difference in comorbidity burden have been implied to be responsible for the paradox. We performed a retrospective review from 2001 to 2012 of critically ill patients from the Medical Information Mart for Intensive Care database. We included 11,433 patients and classified them according to body mass index (BMI) and comorbidity burden (Elixhauser comorbidity measure). The odds of inpatient mortality were lower in obese patients compared to patients with normal BMI; in group with the least comorbidity score (Elixhauser <0) [OR: 0.47, CI (0.28–0.80), p-value 0.006] and higher comorbidity scores, (Elixhauser 1–5) [(OR: 0.66, CI (0.46–0.95), p-value 0.02)] and (Elixhauser 6–13) [OR: 0.69, CI (0.53–0.92), p-value 0.01]. 30-day mortality was also significantly lower in obese patients, in groups with the lowest (Elixhauser <0) [OR:49, CI (0.31–0.77), p-value 0.002] as well as the highest comorbidity burden (Elixhauser >14) [OR:0.59, CI (0.45–0.77), p-value <.001]. Subgroup analysis in patients with various comorbidities showed better outcomes in obese patients. These findings show that the decreased odds of mortality in critically ill obese patients is independent of the comorbidity burden or type of comorbidity.
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: This study was supported by a grant from the Research for Health in Erie County.

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Chest

Clinical Investigations in Critical CareMorbid Obesity in the Medical ICU

Study objective

Design

Setting

Methods

Results

Conclusion

Section snippets

Patients

Demographic Characteristics

Discussion

Am J Clin Nutr

Am J Clin Nutr

Chest

Br J Anaesth

Chest

Chest

Medical hazards of obesity

Ann Intern Med

Increasing prevalence of overweight among US adults: The National Health and Nutrition Examination Surveys, 1960 to 1991

JAMA

Update: prevalence of overweight among children, adolescents and adults–United States 1988–1994

MMWR Morb Mortal Wkly Rep

Prevalence of obesity

Endocrinol Metab Clin North Am

Outcomes of critically ill patients denied consideration for liver transplantation

Am J Respir Crit Care Med

The American-European Consensus Conference on ARDS: definitions, mechanisms, relevant outcomes, and clinical trial coordination

Am J Respir Crit Care Med

A coefficient of agreement for nominal scales

Educ Psychol Meas

Multiple regression for physiological data analysis: the problem of multicollinearity

Am J Physiol

Body-mass index and mortality in a prospective cohort of U.S. adults

N Engl J Med

Body mass index and mortality in nonsmoking older adults: The Cardiovascular Health Study

Am J Public Health

Body weight and mortality: a 27-year follow up of middle age men

JAMA

Obesity and increased mortality in blunt trauma

J Trauma

Clinical Investigations in Critical Care
Morbid Obesity in the Medical ICU