Hypoxic Ventilatory Responses and Gas Exchange in Patients with Parkinson’s Disease

Abstract

Ventilatory responses to isocapnic, progressive hypoxic rebreathing (HVR), in supine and sitting positions, lung ventilation and gas exchange while breathing air and during 5 min of breathing 11% O₂ in N₂ were studied in 12 healthy young (20–28 years), 5 old (57–73 years) male subjects, and in 7 male patients with Parkinson’s disease (PD) aged 55–67 years. The piecewise linear approximation technique was used for evaluation of the ventilatory response curves, which allowed a separate analysis of slopes during minor and severe hypoxia. It has been shown that body position affected HVR. In the range of P_ETO₂ from 60 to 35 mm Hg, the ventilatory response in the sitting position was higher than supine: in young persons by 43%, in healthy old persons by 76%, and in the PD patients by 211%. No significant differences in HVR to minor hypoxia (P_ETO₂ from 100 to 60 mm Hg) were found in the 3 groups. During severe hypoxia (P_ETO₂ from 60 to 35 mm Hg) the slope of minute ventilation versus O₂ was 4.6 (supine) and 2.6 (sitting) times greater in healthy old men than PD patients’ slopes. PD patients compared to old controls had 32% lower alveolar ventilation, 10% lower P_ETO₂ and 15% elevation of P_ETCO₂ while breathing air; similar differences were found while the patients were breathing 11% O₂. The reduced alveolar ventilation under severe hypoxia in patients with PD could not be attributed to mechanical restriction of lung function. We suggest that the discrepancy in HVR under minor and severe hypoxia results from dysfunction in chemoreception associated with Parkinsonism.

Geriatric Men at Altitude: Hypoxic Ventilatory Sensitivity and Blood Dopamine Changes

“…Previous studies in normal humans have shown that aging is associated with a reduced ventilatory response to hypoxia [7, 8, 9, 38]. Although our earlier investigation did not find a decrease in HVRs in 5 older male subjects [39], the present study recorded a significant decrease in HVS with age at both sea level and 2,200 m altitude. The fact that this depression was accompanied by an increased DA and DOPA blood content at sea level should corroborate the theory of an inhibitory action for DA on ventilation.…”

Disordered respiration as a levodopa‐induced dyskinesia in Parkinson's disease

“…15 In PD, the ventilatory response to hypoxia is reduced, possibly due to reduced peripheral chemosensitivity. 16 Denervation hypersensitivity of peripheral chemoreceptor dopaminergic neurones to exogenous dopamine has been postulated as a mechanism for L-dopa-induced respiratory dyskinesia 16 but would be more likely to produce tachypnea alone than the erratic breathing pattern observed in the present cases.…”

Respiratory Dysfunction in Parkinson'S Disease

“…3,17 The carotid body is highly dopaminergic and plays a role in the ventilatory response to hypoxia. seccombe et al 20 did not fi nd an abnormal response to mild hypoxia, contradicting previous studies that showed patients in the early stages of Pd to have a subnormal response to hypoxia, 19,22 in addition to a reduced Pod and a normal response to hypercapnia. 19 The mild hypoxia challenge used in the fi rst study may account for the lack of response seen.…”