Our novel LG estimate enables quantification of the severity of ventilatory instability underlying PB, making possible a priori selection of patients whose PB is immediately treatable with CPAP therapy.

Heart failure (HF) is a highly prevalent disease that leads to significant morbidity and mortality. There is increasing evidence that the symptoms of HF are exacerbated by its deleterious effects on lung function. HF appears to cause airway obstruction acutely and leads to impaired gas diffusing capacity and pulmonary hypertension in the longer term. It is postulated that this is the result of recurrent episodes of elevated pulmonary capillary pressure leading to pulmonary oedema and pulmonary capillary stress fracture, which produces lung fibrosis. It is likely that impaired lung function impairs the functional status of HF patients and makes them more prone to central sleep apnoea. (Circ J 2010; 74: 2507 - 2516

Heart failure (HF) and sleep apnoea are common disorders which frequently coexist. Two main types of apnoea occur: one is obstructive which, through recurring episodes of snoring, hypoxaemia, large negative intrathoracic pressures and arousals from sleep leading to downstream inflammatory and autonomic nervous system changes, is thought to be a causative factor to the development of systemic hypertension and HF.

Depending on classification, 32-53% of patients with snoring had depressive symptoms or were on treatment, which is significantly greater than the Australian average of 21%. A simplified depression questionnaire was validated. Severity of depression correlated with sleepiness and hypoxaemia but not with severity of sleep apnoea.

Cheyne-Stokes respiration (CSR) foretells deleterious outcomes in patients with heart failure. Currently, the size of therapeutic intervention is not guided by the patient's underlying pathophysiology. In theory, the intervention needed to resolve CSR, as a control system instability (loop gain >1), can be predicted knowing the baseline loop gain and how much it falls with therapy.In 12 patients with heart failure, we administered an inspiratory carbon dioxide fraction of 1-3% during CSR (n=95 interventions) as a means to reduce loop gain. We estimated the loop gain on therapy (LG), using the baseline loop gain (using hyperpnoea length/cycle length) and its expected reduction (18% per 1% inspired carbon dioxide), and tested the specific hypothesis that LG predicts CSR persistence (LG >1) versus resolution (LG <1).As predicted, when LG >1.0, CSR continued during therapy in 23 out of 25 (92%) trials. A borderline loop gain zone (0.8

Aims: To compare patient- and carer-reported disability in motor neurone disease (MND) using the International Classification of Functioning, Disability and Health (ICF); and to describe carer burden, psychological coping, and quality of life. Methods: A prospective cross-sectional survey of MND patients (n=44) and carers (n=37). Their MND-related problems were linked with ICF categories (second level) using open-ended questionnaires and ‘linkage rules’. Standardized assessments measured carer psychological coping (depression/anxiety/ stress), strain/burden, quality of life (QoL), and coping strategies. Findings: MND patients were older than their carers (mean age 61, carers 57) there were more male patients than carers (66%, carers 27%). Most carers were spouses/partners (89%). MND patients identified 70 ICF categories whereas carers identified 8: body function 15 (carers 0); body structure 5 (carers 0); activities and participation 40 (carers 6); environmental factors 10 (carers 2). Main ICF categories in activities and participation linked by patients and carers were general tasks and demands, mobility, self-care, community, social and civic life. Environmental factors included support and relationships, services, systems and policies. Carer psychological coping and burden were significant, but self-reported QoL for carers was good, possibly related to use of problem-focused coping strategies. Conclusions: ICF adequately incorporates perspectives of MND patients and carers, which may enable development of a ‘core set’ (ICF categories selected by experts that list issues in impairment, disability, participation, and environmental factors that need to be addressed in multidisciplinary care settings) to optimize care. Reduction in carer burden will optimize outcomes for MND carers and patients.

Low resting pulmonary diffusing capacity in heart failure is indicative of high dead space ventilation during exercise, leading to excessive and inefficient ventilation. These findings would support the concept of pulmonary vasculopathy leading to altered ventilation perfusion matching (increased dead space) and resultant dyspnea, independent of markers of cardiac function.

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