Predictors of nocturnal oxygen desaturation in pulmonary arterial hypertension.

BACKGROUND: Sleep may be associated with significant respiratory compromise in patients with lung disease and can result in hypoxia. In patients with pulmonary arterial hypertension (PAH), nocturnal desaturation may not be reflected in daytime evaluations of oxygenation and can lead to worsening pulmonary hemodynamics. The study was conducted to determine the prevalence and significance of nocturnal oxygen desaturation in patients with PAH. METHODS: A cross-sectional study conducted at the Cleveland Clinic. Patients were followed up at our institution except for the overnight oximetry study done at home. Data regarding degree of nocturnal desaturation, demographics, hemodynamics, pulmonary function, and functional capacity were collected. RESULTS: Forty-three patients (mean age, 47.9 +/- 13.5 years [+/- SD]; 36 women and 7 men) underwent nocturnal oximetry. The etiology of PAH included idiopathic PAH (88%) and PAH associated with connective tissue diseases (12%). The majority of patients were New York Heart Association functional class II (42%) or III (53%). Thirty patients (69.7%) spent > 10% of sleep time with oxygen saturation by pulse oximetry < 90%. Desaturators were older (p = 0.024) and had higher hemoglobin (p = 0.002). Sixteen of 27 patients (59%) without desaturation < 90% during a 6-min walk test were nocturnal desaturators. Nocturnal desaturators had higher brain natriuretic protein (p = 0.004), lower cardiac index (p = 0.03), and higher mean right atrial pressure (p = 0.09), mean pulmonary artery pressure, and pulmonary vascular resistance. On echocardiography, desaturators were more likely to have moderate or severe right ventricular dilation (p = 0.04) and pericardial effusion. Only one patient had significant sleep apnea. CONCLUSIONS: Nocturnal hypoxemia is common in PAH patients and correlates with advanced pulmonary hypertension and right ventricular dysfunction. Approximately 60% patients without exertional hypoxia had nocturnal desaturation. Overnight oximetry should be considered in the routine workup of PAH patients who do not demonstrate exertional desaturation.

Smoking cessation.

Cigarette smoking is the primary cause of chronic obstructive pulmonary disease, and smoking cessation is the most effective means of stopping the progression of chronic obstructive pulmonary disease. Worldwide, approximately a billion people smoke cigarettes and 80% reside in low-income and middle-income countries. Though in the United States there has been a substantial decline in cigarette smoking since 1964, when the Surgeon General's report first reviewed smoking, smoking remains widespread in the United States today (about 23% of the population in 2001). Nicotine is addictive, but there are now effective drugs and behavioral interventions to assist people to overcome the addiction. Available evidence shows that smoking cessation can be helped with counseling, nicotine replacement, and bupropion. Less-studied interventions, including hypnosis, acupuncture, aversive therapy, exercise, lobeline, anxiolytics, mecamylamine, opioid agonists, and silver acetate, have assisted some people in smoking cessation, but none of those interventions has strong research evidence of efficacy. To promote smoking cessation, physicians should discuss with their smoking patients "relevance, risk, rewards, roadblocks, and repetition," and with patients who are willing to attempt to quit, physicians should use the 5-step system of "ask, advise, assess, assist, and arrange." An ideal smoking cessation program is individualized, accounting for the reasons the person smokes, the environment in which smoking occurs, available resources to quit, and individual preferences about how to quit. The clinician should bear in mind that quitting smoking can be very difficult, so it is important to be patient and persistent in developing, implementing, and adjusting each patient's smoking-cessation program. One of the most effective behavioral interventions is advice from a health care professional; it seems not to matter whether the advice is from a doctor, respiratory therapist, nurse, or other clinician, so smoking cessation should be encouraged by multiple clinicians. However, since respiratory therapists interact with smokers frequently, we believe it is particularly important for respiratory therapists to show leadership in implementing smoking cessation.