Lung function and breathing patterns in hospitalised COVID-19 survivors: a review of post-COVID-19 Clinics.

INTRODUCTION: There is relatively little published on the effects of COVID-19 on respiratory physiology, particularly breathing patterns. We sought to determine if there were lasting detrimental effect following hospital discharge and if these related to the severity of COVID-19. METHODS: We reviewed lung function and breathing patterns in COVID-19 survivors > 3 months after discharge, comparing patients who had been admitted to the intensive therapy unit (ITU) (n = 47) to those who just received ward treatments (n = 45). Lung function included spirometry and gas transfer and breathing patterns were measured with structured light plethysmography. Continuous data were compared with an independent t-test or Mann Whitney-U test (depending on distribution) and nominal data were compared using a Fisher's exact test (for 2 categories in 2 groups) or a chi-squared test (for > 2 categories in 2 groups). A p-value of < 0.05 was taken to be statistically significant. RESULTS: We found evidence of pulmonary restriction (reduced vital capacity and/or alveolar volume) in 65.4% of all patients. 36.1% of all patients has a reduced transfer factor (TLCO) but the majority of these (78.1%) had a preserved/increased transfer coefficient (KCO), suggesting an extrapulmonary cause. There were no major differences between ITU and ward lung function, although KCO alone was higher in the ITU patients (p = 0.03). This could be explained partly by obesity, respiratory muscle fatigue, localised microvascular changes, or haemosiderosis from lung damage. Abnormal breathing patterns were observed in 18.8% of subjects, although no consistent pattern of breathing pattern abnormalities was evident. CONCLUSIONS: An "extrapulmonary restrictive" like pattern appears to be a common phenomenon in previously admitted COVID-19 survivors. Whilst the cause of this is not clear, the effects seem to be similar on patients whether or not they received mechanical ventilation or had ward based respiratory support/supplemental oxygen.

Substance Use and Misuse among Adults with Chronic Obstructive Pulmonary Disease in the United States, 2015-2019: Prevalence, Association, and Moderation.

BACKGROUND: Despite the advancements in chronic obstructive pulmonary disease (COPD) treatment, complications related to COPD exacerbation remain challenging. One associated factor is substance use/misuse among adults with COPD. Fewer studies, however, examined the prevalence and association between COPD and substance use and misuse. In addition, limited knowledge existed about the moderation effects of serious psychological distress and gender among adults with COPD and substance use/misuse. We aimed, therefore, to measure such prevalence, association, and moderation from nationally representative samples in the United States. METHOD: Data were drawn from the 2015-2019 National Survey on Drug Use and Health. Weighted logistic regressions were used to measure the associations of last-month tobacco (cigarettes, cigars, pipe, and smokeless tobacco products), other licit and illicit substance use (alcohol, marijuana, cocaine, crack, heroin, hallucinogens, and inhalants), and substance misuse (pain relievers, tranquilizers, stimulants, and sedatives) among adults with COPD. Serious psychological distress and gender were tested as moderators in the association between COPD and substance use/misuse. RESULTS: The findings revealed that adults with COPD [Weighted N = 53,115,718) revealed greater odds of cigarettes [adjusted odds ratio (aOR) = 2.48 (95%CI = 1.80-3.42)) and smokeless tobacco (aOR = 3.65 (95%CI = 1.75-7.65)). However, they were less likely to use alcohol (aOR = 0.61 (95%CI = 0.45-0.84)). Adults with COPD who had serious psychological distress were more likely to use pipe tobacco and alcohol; however, they were less likely to use hallucinogens and inhalants. Finally, males compared to females with COPD were less likely to use smokeless tobacco. CONCLUSION: Adults with COPD in the United States were more likely to use tobacco products and less likely to use alcohol. In addition, serious psychological distress and gender were moderators in associations between COPD and substance use but not in substance misuse. Future studies should longitudinally assess the factors that may contribute to the initiation and progression of substance use and misuse among adults with COPD.

G-Protein-Coupled Receptor (GPCR) Signaling in the Carotid Body: Roles in Hypoxia and Cardiovascular and Respiratory Disease.

The carotid body (CB) is an important organ located at the carotid bifurcation that constantly monitors the blood supplying the brain. During hypoxia, the CB immediately triggers an alarm in the form of nerve impulses sent to the brain. This activates protective reflexes including hyperventilation, tachycardia and vasoconstriction, to ensure blood and oxygen delivery to the brain and vital organs. However, in certain conditions, including obstructive sleep apnea, heart failure and essential/spontaneous hypertension, the CB becomes hyperactive, promoting neurogenic hypertension and arrhythmia. G-protein-coupled receptors (GPCRs) are very highly expressed in the CB and have key roles in mediating baseline CB activity and hypoxic sensitivity. Here, we provide a brief overview of the numerous GPCRs that are expressed in the CB, their mechanism of action and downstream effects. Furthermore, we will address how these GPCRs and signaling pathways may contribute to CB hyperactivity and cardiovascular and respiratory disease. GPCRs are a major target for drug discovery development. This information highlights specific GPCRs that could be targeted by novel or existing drugs to enable more personalized treatment of CB-mediated cardiovascular and respiratory disease.