We have recently reported that patients with advanced primary pulmonary hypertension (PPH) may have nocturnal periodic breathing (PB) closely resembling Cheyne-Stokes respiration (CSR) in congestive heart failure (CHF). Presumably, hemodynamic impairment with prolongation of circulation time of chemical stimuli of breathing plays an important role in the emergence of PB in PPH. Blood gas alterations, ie, hypoxemia and hypocap-nia, are also likely to contribute to breathing instability in patients with PPH. We now describe the clinical course of a patient with PPH and PB in whom sleep-disordered breathing (SDB) disappeared after successful double-lung transplantation.
A 56-year-old woman was first admitted to our hospital in May 1998. She reported shortness of breath during minimal physical exercise (New York Heart Association class III). On physical examination of the tachypneic patient, facial and acral cyanosis and distention of the jugular veins could be detected. Furthermore, slight ankle edema was noted. Pulmonary auscultation was normal. The second heart sound was split, and a holosystolic murmur was heard over the tricuspid valve area. Otorhinolaryngologic and neurologic evaluation did not reveal any abnormalities. Body weight was normal (body mass index of 26.1). comments
Pulmonary function testing with arterial blood gas analysis showed normal ventilation, a marked reduction of diffusion capacity of the lung for carbon monoxide (Dlco), and severe hypoxemia and hypocapnia. Transthoracic echocardiography demonstrated right atrial and ventricular enlargement, whereas the left ventricle had normal dimensions and contractility. Ultrasound Doppler measurements revealed high-grade tricuspid valve insufficiency and marked elevation of systolic pulmonary artery pressure (PAP) [Table 1].
Table 1—Lung Function, Blood Gases, and Echocardiographic Parameters Before and After Double-Lung Transplantation
|FEVb % predicted||87||90|
|Vital capacity, % predicted||86||85|
|Dlco, % predicted||62||85|
|Pao2, mm Hg||45||79|
|Paco2, mm Hg||26||39|
|Left atrial diameter, mm||38||38|
|Left ventricular end-diastolic diameter, mm||45||44|
|Left ventricular ejection fraction, %||65||65|
|Right atrial diameter, mm||45||25|
|Right ventricular diameter, mm||54||28|
|Systolic PAP, mm Hg||90||30|