Oxygen therapy improves cerebral oxygen delivery and neurovascular function in hypoxaemic chronic obstructive pulmonary disease patients

Abstract

We investigated the role of hypoxaemia in cerebral blood flow (CBF), oxygen delivery (CDO ) and neurovascular coupling (coupling of CBF to neural activity; NVC) in hypoxaemic chronic obstructive pulmonary disease (COPD) patients (n = 14). Resting CBF (duplex ultrasound), peripheral oxyhaemoglobin saturation (SpO2; pulse-oximetry) and NVC (transcranial Doppler) were assessed before and after a 20 min wash-in of supplemental oxygen (∼3 l min ). The peripheral oxyhaemoglobin saturation increased from 91.0 ± 3.3 to 97.4 ± 3.0% (P < 0.01), whereas CBF was unaltered (593.0 ± 162.8 versus 590.1 ± 138.5 ml min ; P = 0.91) with supplemental O . In contrast, both CDO (98.1 ± 25.7 versus 108.7 ± 28.4 ml dl ; P = 0.02) and NVC were improved. Specifically, the posterior cerebral artery cerebrovascular conductance was increased to a greater extent after O normalization (+40%, from 20.4 ± 9.9 to 28.0 ± 10.4% increase in conductance; P = 0.04), whereas the posterior cerebral artery cerebrovascular resistance decreased to a greater extent during O normalization (+22%, from -16.7 ± 7.3 to -21.4 ± 6.6% decrease in resistance; P = 0.04). The cerebral vasculature of COPD patients appears insensitive to oxygen, because CBF was unaltered in response to O supplementation leading to improved CDO . In patients, the improvements in CDO and neurovascular function with supplemental O may underlie the cognitive benefits associated with O therapy.

Altered amplitude of low‐frequency fluctuation in basal ganglia correlates to pulmonary ventilation function in COPD patients: A resting‐state fMRI study

“…Alternatively, it is also possible that ALFF does not change so sensitively to the increase in PaO 2 in a relatively lower range in COPD patients. A recent study claims that the cerebral vasculature of COPD patients is insensitive to low‐flow oxygen delivery because of the unaltered CBF (Hoiland et al, ). There are some reports indicating that long‐term oxygen treatment will not improve the survival of COPD patients with moderate resting hypoxemia (Chaouat et al, ; Gorecka, Gorzelak, Sliwinski, Tobiasz, & Zielinski, ).…”

Stable Chronic Obstructive Pulmonary Disease (COPD) Management Under a Tiered Medical System in China

“…In our study, only a small proportion of patients received HNPPV (3% vs. 10.5% vs. 1.0% in teaching hospital vs. second-tier hospital vs. community hospital group), whereas the proportions of patients with very severe air ow limitation (GOLD 4) were 8.9%, 6.9% and 2.0% in the 3 tiers of hospitals, respectively. A meta-analysis including 21 RCTs and 12 observational studies evaluating 51 085 patients showed that home bilevel positive airway pressure and noninvasive home mechanical ventilators were all signi cantly bene cial to COPD patients with hypercapnia 15,16 . Murphy's study 17 showed that among patients with persistent hypercapnia following an AE of COPD, adding home noninvasive ventilation to home oxygen therapy prolonged the time to readmission or death within 12 months.…”

Chronic obstructive pulmonary disease‐induced autonomic dysfunction may be associated with cerebral blood flow regulation and brain function

“…Thus, oxygen therapy appears beneficial for patients with COPD. On the contrary, oxygen therapy did not alter volumetric global CBF (Hoiland et al., ), suggesting that the cerebral vasculature has a low sensitivity to the acute normalization of . From these results, it can be suspected that the contribution of CBF regulation to COPD‐induced cerebrovascular disease or brain dysfunction is likely to be minimal.…”

“…Given this background, Hoiland et al. () have reported, in this issue of Experimental Physiology , the effects of oxygen therapy on cerebral oxygen delivery and neurovascular function in patients with COPD. The authors demonstrated that oxygen therapy improved cerebral oxygen delivery by increasing peripheral oxyhaemoglobin saturation () and enhanced neurovascular function in patients with COPD.…”

“…The work of Hoiland et al. () has clearly described the mechanisms through which oxygen therapy improved survival in patients with COPD. However, in order to identify the mechanisms underlying these effects, we should conduct additional, detailed investigations of the physiological regulatory mechanisms associated with various autonomic functions.…”