MORBIDLY OBESE PATIENT CARDIOPULMONARY DISEASE

Cardiopulmonary Disease in morbidly obese patient
Morbidity and mortality are considerably greater among the obese than in normal-weight patients, and many of the health risks associated with obesity increase progressively and disproportionately with increasing weight. The most significant physiologic disturbances pertain to the cardiopulmonary system.

Coronary artery disease, hypertension, and congestive heart failure are highly correlated with obesity. Both left- and right-sided heart failures are often observed in patients with obesity-hypoventilation syndrome. Obesity has also been linked to depressed left ventricular function even in young, asymptomatic patients.

Obesity is associated with an increased risk of venous thromboembolism, especially after surgery. This is due to several factors found in the obese patient, including decreased levels of circulating antithrombin III, preexisting venous disease, and increased immobility. The obesity-hypoventilation syndrome, also known as the pickwickian syndrome, occurs in 5 percent of the morbidly obese. In obese individuals without hypoventilation, disturbances in the ventilation-perfusion relationship are prevalent. Pulmonary hypertension is a common finding, resulting from chronic hypoxemia, hypoxic pulmonary vasoconstriction, and the added contribution of compromised cardiac function.

The vital capacity, total lung capacity, and functional residual volume are reduced by up to 30 percent in morbidly obese patients. The work of breathing is increased due to higher chest wall and airway resistance and functionally flattened diaphragms. When ventilating obese patients, tidal volume may need to be lowered and adjusted based on inflation pressures and blood gases. Positive end-expiratory pressure may prevent end-expiratory airway closure and atelectasis.

Recognition of the increased risk of cardiorespiratory compromise in the morbidly obese patient is crucial, even when the patient presents to the ED with a problem unrelated to the cardiovascular system. The morbidly obese patient who states that he or she can only sleep in the upright position should be maintained in an upright position as much as possible, or in a lateral position with the head up while performing procedures.

If the patient must remain supine, elevate the head of a patient who is on a backboard by placing towels under the board and utilize continuous pulse oximetry monitoring.