- Morbid obesity presents unique cardiorespiratory challenges in the intensive care unit and frustrates the delivery of routine care. Whether or not obesity itself influences the outcome of critical illness is unclear.
- Morbid obesity leads to heart disease through a number of diverse mechanisms. Therefore, a high index of suspicion for its presence is warranted in the critically ill patient.
- An increased risk of venous thromboembolism in obesity merits an aggressive approach to prophylaxis.
- Cor pulmonale occurs in individuals with nocturnal and diurnal hypoxemia related to the obesity hypoventilation syndrome or coexisting obstructive sleep apnea and obstructive lung disease.
- Although simple obesity has relatively minor effects on pulmonary function, morbid obesity may be associated with reductions in forced vital capacity, forced expiration volume in 1 second, and total lung capacity. An increase in mid to late expiratory flow may be seen.
- Morbid obesity is associated with a significant increase in the percentage of oxygen consumption attributable to the work of breathing. This decreased respiratory reserve results in a predisposition to the development of respiratory failure even after trivial insults.
- Atelectasis is common in the morbidly obese postoperative patient and, in addition to any accompanying sleep-disordered breathing, may lead to respiratory failure. Although conclusive data are lacking, the early use of noninvasive ventilation in the high-risk postoperative patient may prevent the development of respiratory failure.
- Intubation of the morbidly obese patient may be technically challenging because of poor visibility of the glottis and decreased oxygen stores in alveoli from a reduced functional residual capacity.
- Morbidly obese patients should be ventilated in the upright or semi-upright position to improve respiratory system compliance and reduce the work of breathing. Positive end-expiratory pressure between 8 and 15 cm H2O may be necessary to prevent atelectasis.
- Because the compliance of the chest wall is diminished in morbid obesity, a high plateau pressure does not necessarily indicate alveolar overdistention. When using low tidal volume ventilation in the management of the acute respiratory distress syndrome, a plateau pressure of 35 to 40 cm H2O may be acceptable in some patients.
- Ultrasound guidance may be useful in establishing vascular access in the morbidly obese patient.
- Numerous unpredictable alterations in pharmacokinetics have been described in obesity. Reference to published guidelines for individual drugs and close monitoring of clinically available serum drug levels are recommended.
- Attempts by clinicians to accelerate a program of weight loss during the course of critical illness are misguided and may interfere with immune function, wound healing, and respiratory muscle strength. Carefully balanced hypocaloric regimens may be safe.
An ever-increasing percentage of the inhabitants of developed countries is obese or overweight. This trend includes men and women and spans all age groups, including children. Obesity is associated with diabetes mellitus, cardiovascular disease, hypertension, and cancer and confers a reduced life expectancy, particularly in younger and severely obese individuals. Extreme obesity is frequently associated with life-threatening cardiopulmonary disease and presents substantial obstacles to the delivery of routine care. ...