Cerebral oxygen availability during exercise in COPD patients with cognitive impairment

Effect of 12-week head-down strong abdominal breathing on cognitive function in patients with stable chronic obstructive pulmonary disease: a single-centre randomised controlled trial protocol

BACKGROUND

Patients with chronic obstructive pulmonary disease (COPD) often suffer from a combination of mild cognitive impairment (MCI) and a significant reduction in their quality of life. In the exercise programme of pulmonary rehabilitation (PR), pulmonary rehabilitation intervention is often carried out by enhancing respiratory function. Strong abdominal breathing is a kind of breathing method, through which the diaphragm can be exercised, thereby enhancing the deflection distance of the diaphragm during breathing and improving respiratory function. The inversion trainer can meet the different angles of head-down training and also has the characteristics of low cost, easy to operate, and use a wide range of scenarios. According to currently available data, strong abdominal breathing in combination with head-down position has not yet been used in pulmonary rehabilitation in this type of rehabilitation programme. It is valuable to use this device to study PR of cognitive function in patients with COPD.

METHODS

This study was a 12-week single-centre randomised controlled trial and blinding the assessors and data processors of the test. Recruitment is planned for January 1, 2024. It is expected that 81 patients with stable COPD combined with MCI will be recruited and randomly assigned to the head-down strong abdominal breathing group (HG), the fitness qigong eight-duanjin group (BDJ), and the control group (CG) in a 1:1:1 ratio. Using fNIRS (functional near-infrared spectroscopy) to assess brain oxygen availability before and after pulmonary rehabilitation in three periods: before, during and after the intervention. Cognitive functioning is also assessed using the Overall Cognitive Assessment Scale, the Specific Cognitive Functioning Assessment Scale and the Cognitive Behavioural Ability Test.

TRIAL REGISTRATION

The Specialised Committee on Scientific Research and Academic Ethics of the Academic Committee of Anqing Normal University approved the project (ANU2023001). China Clinical Trial Registry approved the study (ChiCTR2300075400) with a registration date of 2023/09/04.

DISCUSSION

The aim of this study was to explore novel exercise rehabilitation methods to improve cognitive function in COPD patients. It results in a lower financial burden and higher participation in pulmonary rehabilitation and improves the quality of survival of patients with COPD.

Effect of Acute Cardiovascular Exercise on Cerebral Blood Flow: A Systematic Review

A single bout of cardiovascular exercise can have a cascade of physiological effects, including increased blood flow to the brain. This effect has been documented across multiple modalities, yet studies have reported mixed findings. Here, we systematically review evidence for the acute effect of cardiovascular exercise on cerebral blood flow across a range of neuroimaging techniques and exercise characteristics. Based on 52 studies and a combined sample size of 1,174 individuals, our results indicate that the acute effect of cardiovascular exercise on cerebral blood flow generally follows an inverted U-shaped relationship, whereby blood flow increases early on but eventually decreases as exercise continues. However, we also find that this effect is not uniform across studies, instead varying across a number of key variables including exercise characteristics, brain regions, and neuroimaging modalities. As the most comprehensive synthesis on the topic to date, this systematic review sheds light on the determinants of exercise-induced change in cerebral blood flow, a necessary step toward personalized interventions targeting brain health across a range of populations.

Benefits of pulmonary rehabilitation in COPD patients with mild cognitive impairment - A pilot study

BACKGROUND

Cognitive impairment might interfere with the efficacy of Pulmonary Rehabilitation (PR) in Chronic Obstructive Pulmonary Disease (COPD). We aimed to identify differential responses to PR between cognitively impaired (CI) and cognitively normal (CN) COPD patients by assessing health status and exercise capacity.

METHODS

Sixty patients (FEV₁: 47 ± 15%) were classified as CI or CN according to the Montreal Cognitive Assessment (MoCA ≤25points) and completed a 3-week inpatient PR program. Cognitive function (neuropsychological battery), health-status (36-Item Short Form Survey [SF-36]), and exercise capacity (6-min walk test [6MWT], cycle-endurance test [CET]) were assessed before and after PR. Responsiveness to PR was estimated by mean change (delta-value [Δ]) and the d-Effect Size (ES).

RESULTS

Twenty-five COPD patients (42%) presented evidence of mild CI prior to PR. Both, CI and CN patients significantly improved global cognitive function, health status (the majority of SF-36 components), and exercise capacity (6MWT and cycle endurance) in response to PR. Compared to CN, CI patients did not improve SF-36 subdomains of "role emotional" and "bodily pain", and demonstrated a lower magnitude of improvement in 6MWT ([Δ]: 25 m; ES: 0.21) compared to CN ([Δ]: 46 m; ES: 0.54).

CONCLUSIONS

PR has favorable effects on global cognitive function, health status, and exercise capacity in both CI and CN COPD patients. There was no concrete evidence to indicate interference of cognitive impairment to PR effectiveness.

Muscle and cerebral oxygenation during cycling in chronic obstructive pulmonary disease: A scoping review

To synthesize evidence for prefrontal cortex (PFC), quadriceps, and respiratory muscle oxygenation using near-infrared spectroscopy (NIRS) during cycling in individuals with chronic obstructive pulmonary disease (COPD). A scoping review was performed searching databases (inception-August 2020): Ovid MEDLINE, EMBASE, Cochrane Systematic Reviews, Cochrane Central Register of Controlled Clinical Trials, CINAHL, SPORTDiscus and Pedro. The search focused on COPD, cycling, and NIRS outcomes. 29 studies (541 COPD participants) were included. Compared to healthy individuals (8 studies), COPD patients at lower cycling workloads had more rapid increases in vastus lateralis (VL) deoxygenated hemoglobin (HHb); lower increases in VL total hemoglobin (tHb) and blood flow; and lower muscle tissue saturation (StO₂). Heliox and bronchodilators were associated with smaller and slower increases in VL HHb. Heliox increased VL and intercostal blood flow compared to room air and supplemental oxygen in COPD patients (1 study). PFC oxygenated hemoglobin (O₂Hb) increased in COPD individuals during cycling in 5 of 8 studies. Individuals with COPD and heart failure demonstrated worse VL and PFC NIRS outcomes compared to patients with only COPD-higher or more rapid increase in VL HHb and no change or decrease in PFC O₂Hb. Individuals with COPD present with a mismatch between muscle oxygen delivery and utilization, characterized by more rapid increase in VL HHb, lower muscle O₂Hb and lower muscle StO₂. PFC O₂Hb increases or tends to increase in individuals with COPD during exercise, but this relationship warrants further investigation. NIRS can be used to identify key deoxygenation thresholds during exercise to inform PFC and muscle oxygenation.

Cerebral cortex and respiratory muscles perfusion during spontaneous breathing attempts in ventilated patients and its relation to weaning outcomes: a protocol for a prospective observational study

INTRODUCTION

In addition to the well-documented factors that contribute to weaning failure, increased energy demands of the respiratory muscles during spontaneous breathing trials (SBTs) might not be met by sufficient increases in energy supplies. This discrepancy may deprive blood and oxygen of other tissues. In this context, restrictions in perfusion of splanchnic organs and non-working muscles during SBT have been associated with weaning failure. However, alterations in perfusion of the brain during the weaning process are less well understood.

OBJECTIVE AND HYPOTHESIS

To investigate whether cerebral cortex perfusion evolves differentially during the transition from mechanical ventilation (MV) to spontaneous breathing between patients failing or succeeding the SBT. We hypothesise that patients failing the SBT will exhibit reduced cerebral cortex perfusion during the transition from MV to spontaneous breathing as compared with patients succeeding the SBT.

METHODS AND ANALYSIS

This single-centre, prospective, observational study will be conducted in a medical Intensive Care unit of University Hospital Leuven, Belgium in ready to wean patients. Blood flow index in the cerebral cortex (prefrontal area), inspiratory (scalene) and expiratory muscle (upper rectus abdominis) and a non-working muscle (thenar eminence) will be simultaneously assessed by near-infrared spectroscopy (NIRS) using the tracer indocyanine green dye. Measurements will be performed on the same day during MV and during SBT. NIRS-derived tissue oxygenation index and cardiac output (by pulse contour analyses) will be recorded continuously. Twenty patients failing an SBT are estimated to be sufficient for detecting a significant difference in the change of cerebral cortex perfusion from MV to SBT (primary outcome) between SBT failure and success patients.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the local ethical committee (Ethische Commissie Onderzoek UZ/KU Leuven protocol ID: S60516). Results from this study will be presented at scientific meetings and congresses and published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT03240263; Pre-results.