Ali A. El-Solh, MD, MPH
University at Buffalo School of
Medicine and Biomedical Sciences
Buffalo, New York, USA

The number of overweight and obese people in the United States has increased dramatically in the past two decades. 1 According to the most recent statistics from the National Health and Nutrition Examination Survey, approximately 97 million Americans are overweight or obese.2 The prevalence of obesity in the United States is three times higher than in France, and one and a half times higher than in the United Kingdom.3 Because morbid obesity is associated with a greater risk for comorbid conditions, it is not surprising that these patients are frequently hospitalized, sometimes with severe illness.

Caring for the critically ill morbidly obese patient is challenging because all routine care is complicated by size and weight. The respiratory system is by far the most affected. Ventilatory compliance is reduced by approximately 35%. The reductions in functional residual capacity and expiratory reserve volume predispose these patients to arterial hypoxemia caused primarily by ventilation-perfusion mismatching.

These respiratory alterations become even more pronounced if these patients are placed in the Trendelenburg position. Because lung volumes may be reduced and airway resistance increased, mechanical ventilation should be initiated with a tidal volume calculated according to ideal body weight (IBW) rather than actual body weight (ABW) to avoid high airway pressures, alveolar overdistention and barotrauma. The addition of positive end-expiratory pressure is highly recommended to facilitate alveolar recruitment and to prevent atelectasis.

Weaning from mechanical ventilation and extubation can be delayed in these patients because increased airway resistance and inefficiency of the respiratory muscles make breathing more difficult.4 Reverse Trendelenburg position at a 45-degree angle may facilitate the weaning process5 by increasing tidal volume and reducing respiratory rate. Once extubation is considered, ensure that you have enough experienced personnel available because reintubation may prove to be difficult, particularly if the initial intubation was problematic, and as such, patient safety may be compromised. Continuous positive airway pressure should be resumed postextubation for those with documented obstructive sleep apnea to minimize the risk of respiratory complications.6

Although morbidly obese patients have excess body fat stores, they are susceptible to protein malnutrition during metabolic stress. Indirect calorimetry is the method of choice to determine energy expenditure. If a calorimeter is not available, the current recommendation calls for nutritional support of 20 to 30 kcal/kg per day based on an obesityadjusted weight (IBW+[ABW-IBW] x0.25)7 and 1.5 to 2.0 grams/kg of protein per IBW per day to ensure nitrogen balance.8 Most of the calories should be given as carbohydrates and fat to prevent fatty acid deficiency. Feeding should be done early, preferably enterally, in order to minimize morbidity due to infection by maintaining the gastrointestinal barrier and improving immune function. Aggressive treatment with intravenous insulin should be implemented early during the course of the disease to improve control of blood glucose9 and to limit potential organ damage.10

With decreased vascularity in adipose tissue, critically ill, morbidly obese patients are at high risk for pressure ulcers. Moisture and urinary incontinence can exacerbate the problem by providing an environment in which microorganisms that contribute to skin breakdown can thrive. Bariatric beds with low air-loss treatment surfaces may alleviate the problem for those who have to stay in bed for more than a few days. Placing a soft cloth between the surfaces of skin folds reduces friction and absorbs moisture.

Nonmedicated powders such as cornstarch tend to clump when applied heavily. Soft, nonstick dressing pads can be used instead to absorb moisture. For patients with deeply infected ulcers, surgical debridement is necessary to promote healing. Vacuumassistive closure can promote the formation of granulation tissue by removing excess interstitial fluid, decreasing localized edema, and increasing blood flow.11 Alternatively, a commercially available form of plateletderived growth factor has been shown in randomized trials to increase the rate of healing and to reduce ulcer volume significantly compared with placebo.12

Nursing care for the morbidly obese poses a significant challenge for the ICU staff. Careful planning and the use of mechanical transfer devices are key in reducing caregivers’ injuries, hospital liability and workers’ compensation claims. Supine sliding board and transfer mattresses can maximize safety in transfers with great reduction of holding friction. Both the hard supine sliding boards and air-driven bariatric transfer mattresses bridge the gap between adjoining surfaces. Moving a patient who is no longer confined to bed rest to a bed that is more conducive to ambulation can be helpful. Commodes made to handle extreme weight should be used and positioned discreetly in the room. The safe transition of a patient from bed to standing position is an important concern. The assistance of a physical therapist is invaluable during this process.

The myriad critical care aspects of the morbidly obese require a true multiprofessional approach. Without concerted initiatives to prevent obesityrelated complications, our healthcare system may soon be overwhelmed.