Determining prognosis in end-stage lung disease is extremely difficult. There is marked variability in survival.
Physician estimates of prognosis vary in accuracy, even in patients who appear end-stage. Even at the time of intubation and mechanical ventilation for respiratory failure from acute exacerbation of chronic obstructive pulmonary disease (COPD), six-month survival cannot be predicted with certainty from simple data easily available to the clinician.
Patients who fit the following parameters can be expected to have the lowest survival rates.
Although the end stages of various forms of lung disease differ in some respects, most follow a final common pathway leading to progressive hypoxemia, cor pulmonale and recurrent infections.
Thus, these guidelines refer to patients with many forms of advanced pulmonary disease. At the present time, it is uncertain what number or combination of these factors might predict six-month mortality; clinical judgment is required.
I. Severity of chronic lung disease documented by:
. Disabling dyspnea at rest, poorly or unresponsive to bronchodilators, resulting in decreased functional activity, e.g., bed-to-chair existence, often exacerbated by other debilitating symptoms such as fatigue and cough. Forced Expiratory Volume in One Second (FEV1), after bronchodilator, less than 30% of predicted, is helpful supplemental objective evidence, but should not be required if not already available.
. Progressive pulmonary disease.
. Increasing visits to Emergency Department or hospitalizations for pulmonary infections and/or respiratory failure.
. Decrease in FEV1 on serial testing of greater than 40 ml per year is helpful supplemental objective evidence, but should not be required if not already available.
II. Presence of cor pulmonale or right heart failure (RHF).
. These should be due to advanced pulmonary disease, not primary or secondary to left heart disease or valvulopathy.
. Cor pulmonale may be documented by:
. Chest x-ray.
. Physical signs of RHF.
III. Hypoxemia at rest on supplemental oxygen.
. pO2 less than or equal to 55 mm Hg on supplemental oxygen.
. Oxygen saturation less than or equal to 88% on supplemental oxygen.
IV. Hypercapnia - pCO2 equal to or greater than 50 mm Hg.
V. Unintentional progressive weight loss of greater than 10% of body weight over the preceding six months.
VI. Resting tachycardia greater than 100/minute in a patient with known severe chronic obstructive pulmonary disease.
U.S. Department of Health and Human Services. Assistant Secretary for Planning and Evaluation. Internet. Accessed on April 29, 2010.