Respiratory Disorders and Quality of Sleep in Patients on the Waiting List for Lung Transplantation

Sleep as a New Target for Improving Outcomes in Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is the most common type of interstitial pneumonia but remains a disease with a poor outcome. Two drugs, pirfenidone and nintedanib, have shown promising results at stalling disease progression; however, the interplay of sleep disruption or sleep disorders overall and in relation to medication effectiveness remains understudied. In the past, there was limited interest in the role of sleep in patients with IPF. Treating physicians tended to address only the daily disabling symptoms while disregarding the possible significant role of sleep alterations or coexisting sleep disorders. During the past few years, there has been more research related to sleep disturbances in patients with IPF and their possible role in sleep and overall life quality, disease progression, and outcome. In summary, sleep in patients with IPF is significantly impaired, with alterations in sleep architecture, changes in sleep breathing pattern, and decreases in oxygen saturation mainly during vulnerable rapid eye movement sleep. There also is evidence that OSA has an increased prevalence in these patients, playing an important role in the already worse sleep quality related to the disease itself. The focus of this review is not only to present current data related to sleep in patients with IPF but also to point out that therapy for sleep problems and OSA is likely to improve sleep and life quality as well as disease outcome. The main priority remains to increase awareness among treating physicians about early diagnosis of OSA in patients with IPF and to emphasize the need for intense future research, especially on the role of intermittent hypoxia superimposed on chronic hypoxia during sleep in patients with IPF.

Physiology of sleep and breathing before and after lung transplantation

During the past 20 years, lung transplantation (LTX) has evolved and it is now accepted as a mainstream modality for care of patients with severe life-threatening respiratory diseases that are refractory to maximal conventional therapies. Improvements in surgical techniques and in antirejection medications have resulted in prolonged survival in these patients. Several studies have explored quality of life after LTX and its improvement has been noted especially in the early period between 3 and 6 months. This article discusses the salient features of the physiology of breathing and sleep disturbances before and after LTX and its alterations during sleep.

Sleep in patients with restrictive lung disease

Restrictive lung disease leads to ventilatory defects and diffusion impairments. These changes may contribute to abnormal nocturnal pathophysiology, including sleep architecture disruption and impaired ventilation and oxygenation. Patients with restrictive lung disease may suffer significant daytime fatigue and dysfunction. Hypercarbia and hypoxemia during sleep may impact progression of lung disease and related symptoms. Little is known about the impact of treatment of sleep disruption on sleep quality and overall prognosis in restrictive lung disease. This review discusses the pathophysiology of sleep and comorbid sleep disorders in restrictive lung diseases including interstitial lung disease, neuromuscular disease, and obesity hypoventilation syndrome.

Obstructive sleep apnea in patients with end-stage lung disease

OBJECTIVES

Little is known about the rate of obstructive sleep apnea (OSA) in patients with end stage lung disease (ESLD). Given the potential deleterious effect of OSA in these patients, we assessed the case-rate and severity of OSA and described associated patient characteristics.

METHODS

Retrospective survey of 60 patients with ESLD referred for lung transplantation evaluation. Demographic, polysomnographic, spirometric, and medication utilization data were extracted and analyzed.

RESULTS

As demographic and polysomnographic data did not differ between obstructive and restrictive patients, we present analysis of pooled data. Demographics/physiology: median age was 58.5 years, 52% males, mean BMI 32.3 kg/m(2), 52% obstructive. Sleep variables (all medians): total sleep time (TST) 312 min, sleep efficiency 77%, minimal oxygen saturation 84%, apnea hypopnea (AHI) 9.7, respiratory disturbance index (RDI) 12.7 events/h of sleep. Sixty-seven percent had RDI > 5; 21% had RDI between 15 and 30; and 21% had RDI > 30. Periodic limb movement index ≥ 15/h sleep was present in 21.7%. An independent positive correlation between DLCO% and RDI was noted (r = 0.41, p < 0.01). The minimal oxygen saturation was negatively correlated with the RDI (r = -0.34, p < 0.01). The use of ACE inhibitors was associated with moderate-to-severe OSA (odd ratio of 4.67, CI 1.45-15.03; p = 0.017).

CONCLUSIONS

In patients with ESLD, organic sleep disorders are common. Greater severity of OSA was associated with the higher DLCO% and lower oxygen saturation.

[Idiopathic pulmonary fibrosis and sleep disorders]

Idiopathic pulmonary fibrosis (IPF) is the most common interstitial lung disease. Despite progress made in understanding the pathophysiological mechanisms behind the development of the disease, its prognosis is poor. For this reason, any measure to improve the quality of life for these patients should be preferred. Some authors are interested in sleep disorders, and possible impact on quality of life. Patients with IPF have lowered scores of quality of life compared to those found in general population, with some correlation with the scores of sleep quality. There is a hyperfragmentation with many arousals and desaturation events. Some authors also report an apnea-hypopnea index higher in these patients, but these data are not found in all the studies. Correcting these obstructive phenomena may have a beneficial effect on survival, which would make systematic the sleep assessment in these patients. Finally, the relationship between IPF, gastroesophageal reflux and sleep apnea syndrome remains unclear.

Severe mixed sleep apnea after bilateral lung transplantation in a cystic fibrosis patient: a case report

BACKGROUND

Lung transplantation is the only treatment for end-stage lung disease in selected patients. After lung transplantation, patient recovery is often slow owing to severe underlying diseases in the patient producing hypoxemia before, during, and after surgery, as well as infections and rejection episodes. Postoperative breathing and ventillatory disorders are also associated with diaphragmatic dysfunction and/or phrenic nerve damage.

METHODS

Herein we have reported a case of a 35-year-old man undergoing bilateral lung transplantation owing to worsening of chronic respiratory failure from cystic fibrosis. After uncomplicated surgery, weaning was delayed due to nighttime dyspnea and hypoxemia attributed to diaphragm dysfunction. After improvement of diaphragm function, the symptoms persisted, requiring noninvasive nocturnal ventilatory support. Polysomnography confirmed severe mixed sleep apnea.

RESULTS

Effective treatment with noninvasive bi-level positive airway pressure spontaneous/timed mode (BiPAP S/T) ventilation during the nights rendered the patient symptom free. Polysomnography confirmed successful treatment.

CONCLUSION

Disordered breathing while sleeping is common after solid organ transplantation. BiPAP S/T ventilator therapy was effective to the treat dominantly central sleep apnea in our patient.