High incidence of hyperventilation syndrome after COVID-19

Four- and sixteen-month clinical status of a cohort of patients following hospitalization for COVID-19

BACKGROUND AND OBJECTIVES

Although many symptoms of post-COVID syndrome have been described, a comprehensive evaluation of their prevalence is lacking. We aimed to describe symptoms at 16 months from hospitalization for COVID-19.

METHODS

A telephone assessment was performed one year later in a cohort of COVID-19 survivors hospitalized between March and May 2020 and already evaluated four months after discharge. Patients with relevant symptoms at 16 months, patients who presented symptoms at four months, and all intensive care unit patients were invited for assessment at an outpatient facility. At telephone consultation, respiratory, cognitive, and functional symptoms were assessed. Patients underwent pulmonary function tests, lung CT scans, and psychometric and cognitive tests at the outpatient facility.

RESULTS

Among 478 patients evaluated four months after discharge, 317 (67 %) were assessed at telephone consultation and 124 at ambulatory assessment. At telephone assessment, ≥1 new symptom was reported by 216 patients (68 %), mainly fatigue (53 %), dyspnea (37 %), and memory difficulties (24 %). Seventy-nine patients (25 %) were asymptomatic at four months but declared ≥1 symptom one year later. In patients evaluated twice, the prevalence of cognitive impairment was 45 % at four months and 40 % at 16 months. Depression and post-traumatic symptoms prevalence remained stable, and the prevalence of anxiety significantly decreased. Dysfunctional breathing was detected in 32 % of patients. At 16 months after discharge, lung CT-scan exhibited abnormalities in 30/80 patients (38 %), compared to 52/85 patients (61 %) at four months.

CONCLUSION

At 16 months after hospitalization for COVID-19, 68 % of patients declared symptoms, including patients whose symptoms appeared between 4 and 16 months.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04704388.

Persisting exercise ventilatory inefficiency in subjects recovering from COVID-19. Longitudinal data analysis 34 months post-discharge

BACKGROUND

SARS-CoV-2 infection has raised concerns about long-term health repercussions. Exercise ventilatory inefficiency (EVin) has emerged as a notable long-term sequela, potentially impacting respiratory and cardiovascular health. This study aims to assess the long-term presence of EVin after 34 months and its association with cardiorespiratory health in post-COVID patients.

METHODS

In a longitudinal study on 32 selected post-COVID subjects, we performed two cardiopulmonary exercise tests (CPETs) at 6 months (T0) and 34 months (T1) after hospital discharge. The study sought to explore the long-term persistence of EVin and its correlation with respiratory and cardiovascular responses during exercise. Measurements included also V̇O2peak, end-tidal pressure of CO2 (PETCO2) levels, oxygen uptake efficiency slope (OUES) and other cardiorespiratory parameters, with statistical significance set at p < 0.05. The presence of EVin at both T0 and T1 defines a persisting EVin (pEVin).

RESULTS

Out of the cohort, five subjects (16%) have pEVin at 34 months. Subjects with pEVin, compared to those with ventilatory efficiency (Evef) have lower values of PETCO2 throughout exercise, showing hyperventilation. Evef subjects demonstrated selective improvements in DLCO and oxygen pulse, suggesting a recovery in cardiorespiratory function over time. In contrast, those with pEvin did not exhibit these improvements. Notably, significant correlations were found between hyperventilation (measured by PETCO2), oxygen pulse and OUES, indicating the potential prognostic value of OUES and Evin in post-COVID follow-ups.

CONCLUSIONS

The study highlights the clinical importance of long-term follow-up for post-COVID patients, as a significant group exhibit persistent EVin, which correlates with altered and potentially unfavorable cardiovascular responses to exercise. These findings advocate for the continued investigation into the long-term health impacts of COVID-19, especially regarding persistent ventilatory inefficiencies and their implications on patient health outcomes.

Carotid body dysregulation contributes to Long COVID symptoms

BACKGROUND

The symptoms of long COVID, which include fatigue, breathlessness, dysregulated breathing, and exercise intolerance, have unknown mechanisms. These symptoms are also observed in heart failure and are partially driven by increased sensitivity of the carotid chemoreflex. As the carotid body has an abundance of ACE2 (the cell entry mechanism for SARS-CoV-2), we investigated whether carotid chemoreflex sensitivity was elevated in participants with long COVID.

METHODS

Non-hositalised participants with long-COVID (n = 14) and controls (n = 14) completed hypoxic ventilatory response (HVR; the measure of carotid chemoreflex sensitivity) and cardiopulmonary exercise tests. Parametric and normally distributed data were compared using Student's unpaired t-tests or ANOVA. Nonparametric equivalents were used where relevant. Peason's correlation coefficient was used to examine relationships between variables.

RESULTS

During cardiopulmonary exercise testing the VE/VCO2 slope (a measure of breathing efficiency) was higher in the long COVID group (37.8 ± 4.4) compared to controls (27.7 ± 4.8, P = 0.0003), indicating excessive hyperventilation. The HVR was increased in long COVID participants (-0.44 ± 0.23 l/min/ SpO2%, R2 = 0.77 ± 0.20) compared to controls (-0.17 ± 0.13 l/min/SpO2%, R2 = 0.54 ± 0.38, P = 0.0007). The HVR correlated with the VE/VCO2 slope (r = -0.53, P = 0.0036), suggesting that excessive hyperventilation may be related to carotid body hypersensitivity.

CONCLUSIONS

The carotid chemoreflex is sensitised in long COVID and may explain dysregulated breathing and exercise intolerance in these participants. Tempering carotid body excitability may be a viable treatment option for long COVID patients.

The burden of persistent symptoms after COVID-19 (long COVID): a meta-analysis of controlled studies in children and adults

BACKGROUND

Previous meta-analyses estimating the prevalence of the post-COVID-19 condition (PCC) were confounded by the lack of negative control groups. This may result in an overestimation of the prevalence of those experiencing PCC, as these symptoms are non-specific and common in the general population. In this study, we aimed to compare the burden of persistent symptoms among COVID-19 survivors relative to COVID-19-negative controls.

METHODS

A systematic literature search was conducted using the following databases (PubMed, Web of Science, and Scopus) until July 2023 for comparative studies that examined the prevalence of persistent symptoms in COVID-19 survivors. Given that many of the symptoms among COVID-19 survivors overlap with post-hospitalization syndrome and post-intensive care syndrome, we included studies that compare the prevalence of persistent symptoms in hospitalized COVID-19 patients relative to non-COVID-19 hospitalized patients and in non-hospitalized COVID-19 patients relative to healthy controls that reported outcomes after at least 3 months since infection. The results of the meta-analysis were reported as odds ratios with a 95% confidence interval based on the random effects model.

RESULTS

Twenty articles were included in this study. Our analysis of symptomatology in non-hospitalized COVID-19 patients compared to negative controls revealed that the majority of symptoms examined were not related to COVID-19 infection and appeared equally prevalent in both cohorts. However, non-COVID-19 hospitalized patients had higher odds of occurrence of certain symptoms like anosmia, ageusia, fatigue, dyspnea, and brain fog (P < 0.05). Particularly, anosmia and ageusia showed substantially elevated odds relative to the negative control group at 11.27 and 9.76, respectively, P < 0.05. In contrast, analysis of hospitalized COVID-19 patients compared to those hospitalized for other indications did not demonstrate significantly higher odds for the tested symptoms.

CONCLUSIONS

The persistent symptoms in COVID-19 survivors may result from hospitalization for causes unrelated to COVID-19 and are commonly reported among the general population. Although certain symptoms exhibited higher odds in non-hospitalized COVID-19 patients relative to controls, these symptoms are common post-viral illnesses. Therefore, the persistent symptoms after COVID-19 may not be unique to SARS-CoV-2. Future studies including well-matched control groups when investigating persistent symptoms in COVID-19 survivors are warranted to draw a firm conclusion.

Exercise ventilatory response after COVID-19: comparison between ambulatory and hospitalized patients

Inefficient ventilatory response during cardiopulmonary exercise testing (CPET) has been suggested as a cause of post-COVID-19 dyspnea. It has been described in hospitalized patients (HOSP) with lung parenchymal sequelae but also after mild infection in ambulatory patients (AMBU). We hypothesize that AMBU and HOSP have different ventilatory responses to exercise, due to different etiologies. We analyzed CPET realized between July 2020 and May 2022 of patients with persisting respiratory symptoms 3 mo after COVID-19. Chest computed tomography (CT) scan, pulmonary function tests, quality of life, and respiratory questionnaires were collected. CPET data were specifically explored as a function of ventilation (V̇e) and time. Seventy-nine consecutive patients were included (42 AMBU and 37 HOSP, median: 54 [44-60] yr old, 57% female). Patients were hospitalized for a median of 20 [8-34] days, with pneumonia (41%) or acute respiratory distress syndrome (ARDS; 30%). Among HOSP, 12(32%) patients had abnormal values for spirometry and 18(51%) for carbon monoxide diffusing capacity (P < 0.001). CPET showed no differences between AMBU and HOSP in peak absolute O2 uptake (V̇o2) (1.59 [1.22-2.11] mL·min-1; P = 0.65). Tidal volume (VT) as a function of V̇e, was lower in AMBU than in HOSP (P < 0.01) toward the end of exercise. The slope of the V̇e-CO2 production was higher than normal in both groups (30.9 [26.1-34.3]; P = 0.96). In conclusion, the severity of COVID-19 did not influence the exercise capacity, but AMBU demonstrated a less efficient ventilatory response to exercise as compared with HOSP. CPET with exploration of data as a function of V̇e and throughout the exercise better unveil ventilatory inefficiency.NEW & NOTEWORTHY We evaluated the exercise ventilatory response in patients with persisting dyspnea after severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection. We found that despite similar peak power and peak absolute O2 uptake, tidal volume as a function of ventilation was lower in ambulatory than in hospitalized patients toward the end of exercise, reflecting ventilatory inefficiency. We call for evaluation of minute ventilation with the exploration of data throughout the exercise and not only peak data to better unveil ventilatory inefficiency.

Increased intrapulmonary shunt and alveolar dead space post-COVID-19

Increased intrapulmonary shunt (QS/Qt) and alveolar dead space (VD/VT) are present in early recovery from 2019 Novel Coronavirus (COVID-19). We hypothesized patients recovering from severe critical acute illness (NIH category 3-5) would have greater and longer lasting increased QS/Qt and VD/VT than patients with mild-moderate acute illness (NIH 1-2). Fifty-nine unvaccinated patients (33 males, aged 52 [38-61] yr, body mass index [BMI] 28.8 [25.3-33.6] kg/m2; median [IQR], 44 previous mild-moderate COVID-19, and 15 severe-critical disease) were studied 15-403 days postacute severe acute respiratory syndrome coronavirus infection. Breathing ambient air, steady-state mean alveolar Pco2, and Po2 were recorded simultaneously with arterial Po2/Pco2 yielding aAPco2, AaPo2, and from these, QS/Qt%, VD/VT%, and relative alveolar ventilation (40 mmHg/[Formula: see text], VArel) were calculated. Median [Formula: see text] was 39.4 [35.6-41.1] mmHg, [Formula: see text] 92.3 [87.1-98.2] mmHg; [Formula: see text] 32.8 [28.6-35.3] mmHg, [Formula: see text] 112.9 [109.4-117.0] mmHg, AaPo2 18.8 [12.6-26.8] mmHg, aAPco2 5.9 [4.3-8.0] mmHg, QS/Qt 4.3 [2.1-5.9] %, and VD/VT16.6 [12.6-24.4]%. Only 14% of patients had normal QS/Qt and VD/VT; 1% increased QS/Qt but normal VD/VT; 49% normal QS/Qt and elevated VD/VT; 36% both abnormal QS/Qt and VD/VT. Previous severe critical COVID-19 predicted increased QS/Qt (2.69 [0.82-4.57]% per category severity [95% CI], P < 0.01), but not VD/VT. Increasing age weakly predicted increased VD/VT (1.6 [0.1-3.2]% per decade, P < 0.04). Time since infection, BMI, and comorbidities were not predictors (all P > 0.11). VArel was increased in most patients. In our population, recovery from COVID-19 was associated with increased QS/Qt in 37% of patients, increased VD/VT in 86%, and increased alveolar ventilation up to ∼13 mo postinfection. NIH severity predicted QS/Qt but not elevated VD/VT. Increased VD/VT suggests pulmonary microvascular pathology persists post-COVID-19 in most patients.NEW & NOTEWORTHY Using novel methodology quantifying intrapulmonary shunt and alveolar dead space in COVID-19 patients up to 403 days after acute illness, 37% had increased intrapulmonary shunt and 86% had elevated alveolar dead space likely due to independent pathology. Elevated shunt was partially related to severe acute illness, and increased alveolar dead space was weakly related to increasing age. Ventilation was increased in the majority of patients regardless of previous disease severity. These results demonstrate persisting gas exchange abnormalities after recovery.

Hyperventilation Syndrome Following an Asymptomatic COVID-19 Infection

N/a.

[The role of the cardiopulmonary exercise test and pulmonary rehabilitation in long COVID-19]

INTRODUCTION

Long COVID refers to persistent symptoms, lasting more than 4 weeks after acute SARS-CoV-2 infection, even though the infection itself has been successfully controlled and remedied. Patient complaints are diverse, and the underlying physiopathological mechanisms are not well understood. Dyspnea and muscle fatigue are among the most commonly reported symptoms.

STATE OF THE ART

Cardiopulmonary exercise test (CPET) has been recognized as a useful tool in investigation of unexplained dyspnea. In patients with chronic lung disease, pulmonary rehabilitation is a program designed to counteract dyspnea, to increase exercise capacity and to improve quality of life.

PERSPECTIVES

Publications on CPET and pulmonary rehabilitation are needed in order to deepen comprehension and enhance management of long-COVID-19.

CONCLUSIONS

CPET reports have shown that symptoms persisting in the aftermath of acute SARS-CoV-2 infection may be related to deconditioning, a common occurrence after ICU stay, to cardiac dysautonomia subsequent to critical infections and, finally, to dysfunctional breathing subsequent to mild infections. These findings justify pulmonary rehabilitation, which has proven to be effective regardless of the severity of the initial infection, not only immediately after hospital discharge, but also at later points in time.

Novel Respiratory Therapy for the Improvement of Post COVID Condition Symptoms: A Case Series

INTRODUCTION

Speech-language pathologists are seeing a growing number of patients whose voice and upper airway symptoms are complicated by dyspnea, cognitive difficulties, anxiety, extreme fatigue, and other debilitating post COVID symptoms. These patients are often less responsive to traditional speech-language pathology treatments and there is emerging literature that suggests dysfunctional breathing (DB) might contribute to dyspnea and other symptoms in this patient population. Treatment of DB through breathing retraining has been shown to improve breathing and successfully reduce symptoms similar to those seen in patients with long COVID. There is some preliminary evidence that breathing retraining is helpful for patients with post COVID condition symptoms. However, breathing retraining protocols tend to be heterogeneous and are often not systematic or well described.

METHODS

This case series reports on an Integrative Breathing Therapy (IBT) protocol used in patients diagnosed with post COVID condition symptoms attending an otolaryngology clinic who presented with signs and symptoms of DB. A systematic evaluation of the biomechanical, biochemical, and psychophysiological dimensions of DB based on principles of IBT was performed on each patient to enable targeted patient-centered care. Patients were then provided with intensive breathing retraining that aimed to comprehensively improve breathing functionality in all these three dimensions of breathing. Treatment involved 6-12 sessions of weekly 1-hour group telehealth sessions combined with 2-4 individual sessions.

RESULTS

All participants showed improvements in the parameters of DB measured and also reported a reduction in symptoms and improved daily function.

CONCLUSIONS

These findings suggest that patients with long COVID who present with signs and symptoms of DB might respond positively to comprehensive and intensive breathing retraining that addresses biochemical, biomechanical, and psychophysiological dimensions of breathing. More research is required to further refine this protocol and confirm its effectiveness through a controlled trial.

Risk factors for impaired respiratory function post COVID-19: A prospective cohort study of nonhospitalized and hospitalized patients

BACKGROUND

Severe COVID-19 increases the risk for long-term respiratory impairment, but data after mild COVID-19 are scarce. Our aims were to determine risk factors for reduced respiratory function 3-6 months after COVID-19 infection and to investigate if reduced respiratory function would relate to impairment of exercise performance and breathlessness.

METHODS

Patients with COVID-19 were enrolled at the University Hospitals of Umeå and Örebro, and Karlstad Central Hospital, Sweden. Disease severity was defined as mild (nonhospitalized), moderate (hospitalized with or without oxygen treatment), and severe (intensive care). Spirometry, including diffusion capacity (DL_CO ), was performed 3-6 months after hospital discharge or study enrollment (for nonhospitalized patients). Breathlessness (defined as ≥1 according to the modified Medical Research Council scale) and functional exercise capacity (1-min sit-to-stand test; 1-MSTST) were assessed.

RESULTS

Between April 2020 and May 2021, 337 patients were enrolled in the study. Forced vital capacity and DL_CO were significantly lower in patients with severe COVID-19. Among hospitalized patients, 20% had reduced DL_CO , versus 4% in nonhospitalized. Breathlessness was found in 40.6% of the participants and was associated with impaired DL_CO . A pathological desaturation or heart rate response was observed in 17% of participants during the 1-MSTST. However, this response was not associated with reduced DL_CO .

CONCLUSION

Reduced DL_CO was the major respiratory impairment 3-6 months following COVID-19, with hospitalization as the most important risk factor. The lack of association between impaired DL_CO and pathological physiological responses to exertion suggests that these physiological responses are not primarily related to decreased lung function.

Changes in cardiopulmonary exercise capacity and limitations 3-12 months after COVID-19

RATIONALE

To describe cardiopulmonary function during exercise 12 months after hospital discharge for coronavirus disease 2019 (COVID-19), assess the change from 3 to 12 months, and compare the results with matched controls without COVID-19.

METHODS

In this prospective, longitudinal, multicentre cohort study, hospitalised COVID-19 patients were examined using a cardiopulmonary exercise test (CPET) 3 and 12 months after discharge. At 3 months, 180 performed a successful CPET, and 177 did so at 12 months (mean age 59.3 years, 85 females). The COVID-19 patients were compared with controls without COVID-19 matched for age, sex, body mass index and comorbidity. Main outcome was peak oxygen uptake (V'_{O2  peak}).

RESULTS

Exercise intolerance (V'_{O2  peak} <80% predicted) was observed in 23% of patients at 12 months, related to circulatory (28%), ventilatory (17%) and other limitations including deconditioning and dysfunctional breathing (55%). Estimated mean difference between 3 and 12 months showed significant increases in V'_{O2  peak} % pred (5.0 percentage points (pp), 95% CI 3.1-6.9 pp; p<0.001), V'_{O2  peak}·kg^-1 % pred (3.4 pp, 95% CI 1.6-5.1 pp; p<0.001) and oxygen pulse % pred (4.6 pp, 95% CI 2.5-6.8 pp; p<0.001). V'_{O2  peak} was 2440 mL·min^-1 in COVID-19 patients compared to 2972 mL·min^-1 in matched controls.

CONCLUSIONS

1 year after hospital discharge for COVID-19, the majority (77%), had normal exercise capacity. Only every fourth had exercise intolerance and in these circulatory limiting factors were more common than ventilator factors. Deconditioning was common. V'_{O2  peak} and oxygen pulse improved significantly from 3 months.

Evaluation of long-term sequelae by cardiopulmonary exercise testing 12 months after hospitalization for severe COVID-19

BACKGROUND

Cardiopulmonary exercise testing (CPET) is an important clinical tool that provides a global assessment of the respiratory, circulatory and metabolic responses to exercise which are not adequately reflected through the measurement of individual organ system function at rest. In the context of critical COVID-19, CPET is an ideal approach for assessing long term sequelae.

METHODS

In this prospective single-center study, we performed CPET 12 months after symptom onset in 60 patients that had required intensive care unit treatment for a severe COVID-19 infection. Lung function at rest and chest computed tomography (CT) scan were also performed.

RESULTS

Twelve months after severe COVID-19 pneumonia, dyspnea was the most frequently reported symptom although only a minority of patients had impaired respiratory function at rest. Mild ground-glass opacities, reticulations and bronchiectasis were the most common CT scan abnormalities. The majority of the patients (80%) had a peak O₂ uptake (V'O₂) considered within normal limits (median peak predicted O₂ uptake (V'O₂) of 98% [87.2-106.3]). Length of ICU stay remained an independent predictor of V'O₂. More than half of the patients with a normal peak predicted V'O₂ showed ventilatory inefficiency during exercise with an abnormal increase of physiological dead space ventilation (VD/Vt) (median VD/VT of 0.27 [0.21-0.32] at anaerobic threshold (AT) and 0.29 [0.25-0.34] at peak) and a widened median peak alveolar-arterial gradient for O₂ (35.2 mmHg [31.2-44.8]. Peak PetCO₂ was significantly lower in subjects with an abnormal increase of VD/Vt (p = 0.001). Impairments were more pronounced in patients with dyspnea. Peak VD/Vt values were positively correlated with peak D-Dimer plasma concentrations from blood samples collected during ICU stay (r² = 0.12; p = 0.02) and to predicted diffusion capacity of the lung for carbon monoxide (D_LCO) (r² =  - 0.15; p = 0.01).

CONCLUSIONS

Twelve months after severe COVID-19 pneumonia, most of the patients had a peak V'O₂ considered within normal limits but showed ventilatory inefficiency during exercise with increased dead space ventilation that was more pronounced in patients with persistent dyspnea.

TRIAL REGISTRATION

NCT04519320 (19/08/2020).

Respiratory psychophysiology and COVID-19: A research agenda

After multiple waves of the COVID-19 pandemic, it has become clear that the impact of SARS-CoV-2 will carry on for years to come. Acutely infected patients show a broad range of disease severity, depending on virus variant, vaccination status, age and the presence of underlying medical and physical conditions, including obesity. Additionally, a large number of patients who have been infected with the virus present with post-COVID syndrome. In September 2020, the International Society for the Advancement of Respiratory Psychophysiology organized a virtual interest meeting on 'Respiratory research in the age of COVID-19', which aimed to discuss how research in respiratory psychophysiology could contribute to a better understanding of psychophysiological interactions in COVID-19. In the resulting current paper, we propose an interdisciplinary research agenda discussing selected research questions on acute and long-term neurobiological, physiological and psychological outcomes and mechanisms related to respiration and the airways in COVID-19, as well as research questions on comorbidity and potential treatment options, such as physical rehabilitation.

Validation Criteria for PETCO2 Kinetics during the Hyperventilation Provocation Test in the Diagnosis of Idiopathic Hyperventilation Syndrome

Background: The hyperventilation provocation test (HPTest) is a diagnostic tool for idiopathic hyperventilation syndrome (HVS), encountered in some long-COVID patients. However, interpretation of the HPTest remains unclear regarding the relevant PETCO2 values to focus on and whether subjective symptoms should be considered. This study aimed to re-evaluate objective HPTest results for diagnosing HVS by determining accurate PETCO2 kinetics in two groups of patients previously screened via the Nijmegen questionnaire (NQ). Methods: The kinetics of PETCO2 during the HPTest were mathematically modeled and compared between 37 HVS patients (NQ ≥23/64) and 37 healthy controls (NQ <23/64) matched for gender, age, and body dimensions. AUC values with sensitivity and specificity were calculated, and analysis was monitored in a validation cohort of 152 routine HPTests. Results: A threshold value of a less than 12.8 mmHg increment of PETCO2 at the 5th minute of the recovery phase of the HPTest diagnosed HVS patients with excellent sensitivity (0.92) and specificity (0.84). These results were confirmed in the validation cohort, highlighting the presence of 24% false positives/negatives when diagnosing on the basis of complaints in the NQ. Conclusions: For HVS diagnosis, we suggest considering the HPTest, which can more reliably reflect the mechanisms of CO2 homeostasis and the response of the respiratory center to a stimulus, regardless of the subjective onset of symptoms.

Is There a Relationship between Hyperventilation Syndrome and History of Acute SARS-CoV-2 Infection? A Cross-Sectional Study

Following COVID-19 infection, many patients suffer from long-lasting symptoms that may greatly impair their quality of life. Persisting dyspnea and other functional respiratory complaints can evoke hyperventilation syndrome (HVS) as a putative contributor to long-COVID presentation in COVID-19 survivors. We aimed to assess the possible relationship between HVS and previous acute COVID-19 infection. We designed a cross-sectional, single-center study, including all patients consecutively referred to our Lung Function and Exercise Testing Department between January and June 2021. Participants completed a systematic Nijmegen Questionnaire, a modified Medical Research Council dyspnea scale assessment, a post-COVID screening questionnaire, and performed a standardized lung function test. The population was divided according to HVS diagnosis, defined as a Nijmegen score of > 23/64. The occurrence of previous COVID-19 infection was compared according to the Nijmegen score after adjustment for potential confounders by multivariate logistic regression. In total, 2846 patients were included: 1472 men (51.7%) with a mean age of 56 (±16.6) years. A total of 455 patients (16%) declared a previous SARS-CoV-2 infection, and 590 patients presented a positive score (>23/64) in the Nijmegen Questionnaire (20.7%). Compared with COVID-19-free patients, there was an increased occurrence of HVS+ in cases of COVID-19 infection that did not require hospitalization (aOR = 1.93 [1.17−3.18]). The results of this large-scale, cross-sectional study suggest an association between HVS diagnosis and a history of COVID-19 disease in patients who were not hospitalized.

Level of Dyspnoea in Patients with COVID-19 in Poland

OBJECTIVES

The study aimed to assess the level of dyspnoea during the COVID-19 pandemic in Poland.

METHODS

The online questionnaire was conducted among 204 Polish adult respondents with a positive SARS-CoV-2 test result. The level of dyspnoea was assessed by the modified Medical Research Council (MRC) Dyspnoea Scale in Polish.

RESULTS

Dyspnoea is most common in patients with severe COVID-19, and the prevalence of dyspnoea in the study population of patients with COVID-19 was low (34% respondents presented with dyspnoea with a score of 1 or higher).

CONCLUSIONS

There is a need for further investigation and close monitoring of the extent of dyspnoea in different social groups, especially in the event of a prolonged pandemic and the emergence of further waves of COVID-19.

Fatigue Is a Major Symptom at COVID-19 Hospitalization Follow-Up

Persistent symptoms after hospitalization with COVID-19 are common, but the frequency and severity of these symptoms are insufficiently understood. We aimed to describe symptoms and pulmonary function after hospitalization with COVID-19. Patients hospitalized with COVID-19 in Central Denmark Region were invited for follow-up 3 months after discharge. Clinical characteristics, patient reported outcomes (Fatigue Assessment Scale (FAS), anxiety and depression (HADS)), symptoms, pulmonary function test and 6-min walk test were collected. We included 218 patients (mean age 59.9 (95% CI: 58.2, 61.7), 59% males). Fatigue, dyspnea and impaired concentration were the most prevalent symptoms at follow-up. Using FAS, 47% reported mild-to-moderate fatigue and 18% severe fatigue. Mean HADS was 7.9 (95% CI: 6.9, 8.9). FAS was correlated to HADS (β = 0.52 (95% CI: 0.44, 0.59, p < 0.001)). Mean DLCO was 80.4% (95% CI: 77.8, 83.0) and 45% had DLCO ˂ 80%. Mean DLCO was significantly reduced in patients treated in the ICU (70.46% (95% CI 65.13, 75.79)). The highest FAS and HADS were seen in patients with the shortest period of hospitalization (2.1 days (95% CI: 1.4, 2.7)) with no need for oxygen. In conclusion, fatigue is a common symptom after hospitalization for COVID-19 and ICU treatment is associated to decreased diffusion capacity.

Post-acute COVID-19 syndrome

Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the coronavirus disease 2019 (COVID-19) pandemic that has resulted in millions of deaths and a major strain on health systems worldwide. Medical treatments for COVID-19 (anticoagulants, corticosteroids, anti-inflammatory drugs, oxygenation therapy and ventilation) and vaccination have improved patient outcomes. The majority of patients will recover spontaneously or after acute-phase management, but clinicians are now faced with long-term complications of COVID-19 including a large variety of symptoms, defined as "post-acute COVID-19 syndrome". Most studies have focused on patients hospitalised for severe COVID-19, but acute COVID-19 syndrome is not restricted to these patients and exists in outpatients. Given the diversity of symptoms and the high prevalence of persistent symptoms, the management of these patients requires a multidisciplinary team approach, which will result in the consumption of large amounts of health resources in the coming months. In this review, we discuss the presentation, prevalence, pathophysiology and evolution of respiratory complications and other organ-related injuries associated with post-acute COVID-19 syndrome.

Update of the Potential Treatments for Psychiatric and Neuropsychiatric Symptoms in the Context of the Post-COVID-19 Condition: Still a Lot of Suffering and Many More Things to Learn

Background: The World Health Organization (WHO) has defined a post-COVID-19 condition. Some of these symptoms can be categorized as psychiatric long COVID-19 if they appeared in the aftermath of COVID-19, including depression, anxiety, post-traumatic stress disorder, somatic symptoms disorders such as hyperventilation syndrome, fatigue, cognitive and sleep disorders. Psychiatric and neuropsychiatric post-COVID-19 present mental health specialists with difficult challenges because of its complexity and the multiple ways in which it integrates into a singular somatic context. Methods: We conducted a systematic research paradigm from SARS-CoV-2 using LitCOVID and Web of Science to search management strategies and potential treatments for psychiatric post-COVID-19 symptoms. Results: Management strategies must be based on a multidisciplinary approach to promote the global evaluation of psychiatric and physical symptoms, systematic detection and prevention. Selective serotonin reuptake inhibitors appear to be the best choice to treat post-COVID-19 depression and anxiety disorders, and tofisopam could be helpful for anxiety. Cognitive behavioral therapy techniques adjusted to post-COVID-19 fatigue, functional remediation, extracorporeal apheresis, transcutaneous auricular vagus nerve stimulation, monoclonal antibodies, flavonoids, oxytocin or L-carnitine all represent hypothetical therapeutic avenues that remain to be evaluated in clinical trials. Conclusions: Psychiatric and neuropsychiatric post-COVID-19 symptoms occur frequently and are debilitating. Attention should be paid to this condition and studies undertaken to specify the effective treatments.

Dyspnea in Post-COVID Syndrome Following Mild Acute COVID-19 Infections: Potential Causes and Consequences for a Therapeutic Approach

Dyspnea, shortness of breath, and chest pain are frequent symptoms of post-COVID syndrome (PCS). These symptoms are unrelated to organ damage in most patients after mild acute COVID infection. Hyperventilation has been identified as a cause of exercise-induced dyspnea in PCS. Since there is a broad overlap in symptomatology with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), causes for dyspnea and potential consequences can be deduced by a stringent application of assumptions made for ME/CFS in our recent review papers. One of the first stimuli of respiration in exercise is caused by metabolic feedback via skeletal muscle afferents. Hyperventilation in PCS, which occurs early on during exercise, can arise from a combined disturbance of a poor skeletal muscle energetic situation and autonomic dysfunction (overshooting respiratory response), both found in ME/CFS. The exaggerated respiratory response aggravating dyspnea does not only limit the ability to exercise but further impairs the muscular energetic situation: one of the buffering mechanisms to respiratory alkalosis is a proton shift from intracellular to extracellular space via the sodium–proton-exchanger subtype 1 (NHE1), thereby loading cells with sodium. This adds to two other sodium loading mechanisms already operative, namely glycolytic metabolism (intracellular acidosis) and impaired Na⁺/K⁺ATPase activity. High intracellular sodium has unfavorable effects on mitochondrial calcium and metabolism via sodium–calcium-exchangers (NCX). Mitochondrial calcium overload by high intracellular sodium reversing the transport mode of NCX to import calcium is a key driver for fatigue and chronification. Prevention of hyperventilation has a therapeutic potential by keeping intracellular sodium below the threshold where calcium overload occurs.

Verification of the Psychometric Characteristics of the Nijmegen Questionnaire for the Diagnosis of Dysfunctional Breathing During the COVID-19 Pandemic on a Russian Sample

The purpose of the study was to check the psychometric properties of the Nijmegen questionnaire (NQ) (Van Dixhoorn, Duivenvoorden, 1985), aimed at diagnosing the presence of signs of dysfunctional breathing (DВ) according to self–reports of respondents in the conditions of the COVID-19 pandemic in a Russian-speaking sample. The study sample consisted of 1 362 respondents (1 153 women and 209 men) aged 18 to 88 years (mean age 38.3±11.4) who filled out an online questionnaire from April to December 2020 during the COVID-19 pandemic. The following methods were used to test the construct validity of the Russian version of the NQ: 1) Perceived Stress Scale-10 (PSS-10; Ababkov et al., 2016); 2) State-Trait Anxiety Inventory (STAI, Khanin, 1976), the scales of which were modified to measure the level of anxiety during a pandemic (State anxiety) and before the pandemic (Trait anxiety) (Pervichko et al., 2020); 3) The Symptom Check List-32 (SCL-32) (Mitina, Gorbunova, 2011); (4) An abridged version of the Six-Factor Personality Inventory HEXACO-24 (Egorova et al, 2019). The study participants also completed a socio-demographic questionnaire (Pervichko et al., 2020). The results of checking the Russian-language version of the NQ for reliability are presented: the value of the internal consistency coefficient α-Cronbach for the integral indicator = 0.877. Four subscales were identified, the indicators of which improved when the questionnaire was reduced to 10 points. Internal convergent and discriminant validity has been verified for the abridged version. The external constructive validity of the questionnaire is proved. High rates of correlation with stress, situational and personal anxiety, as well as other symptoms of psychological distress were revealed. In addition, a high correlation with emotionality has been established. The problem of the "threshold" value of NQ required to identify the formed symptom complex of DB is discussed. The prevalence of DB symptoms before and during the pandemic was compared. A significant difference in the indicators on the scale for men and women was established. Using the obtained Russian-language version of NQ, it was shown that in the conditions of the COVID-19 pandemic, 27.7% of the study participants who were not sick with COVID-19 showed signs of a formed DB symptom complex, which is more than twice higher than the population indicators in the pre-pandemic period. The frequency of occurrence of the holistic symptom complex of DB in women is three times higher than in men: 31.0% vs 9.1% (p<0.001). The results of the study allow us to conclude that NQ is a reliable and valid tool for diagnosing the severity of DB symptoms, which can be recommended for use as an express diagnostic tool for the presence of psychogenically caused respiratory disorders in persons complaining of "difficulty breathing" in the absence of objective grounds.

Respiratory rehabilitation for Covid-19 related persistent dyspnoea: A one-year experience

Background

Growing consideration is emerging regarding the burden of persisting sequelae after SARS-CoV-2 infection. Out-patients exhibiting long Covid may benefit from ambulatory rehabilitation which is, to date, poorly documented.

Methods

A longitudinal follow-up over a one-year period was conducted in two ambulatory rehabilitation structures in order to describe the characteristics of real-life patients referred with Covid-19 sequelae and their evolution over the course of rehabilitation.

Results

39 consecutive patients were included from April 1st^, 2020 to April 1st^, 2021. Patients were middle-aged (48 ± 15yr), without comorbidities, and mostly mild to moderate SARS-CoV-2 infection (25(64%) not requiring hospitalisation). Rehabilitation referral was considered with a median delay of 73[34–178] days after disease onset. Most prevalent symptoms were dyspnoea (n = 35(90%)) and fatigue (n = 30(77%)). Hyperventilation syndrome was highly frequent (n = 12(34%)). 29(74%) patients presented with prolonged functional sequelae, which was associated with younger age (43 ± 14 vs. 50 ± 10yr; p = 0.002), greater prevalence of hyperventilation syndrome (n = 12(41%) vs. 0(0%); p = 0.255) and poorer quality of life (VQ-11; 31 ± 10 vs. 23 ± 9; p = 0.030). Over the course of rehabilitation, exertional dyspnoea, 6-min walking distance, 3-min sit-to-stand test, hyperventilation syndrome prevalence and quality of life significantly improved.

Conclusion

Hyperventilation is frequent in long Covid and may explain persistent dyspnoea as well as altered quality of life. Our data support screening of hyperventilation syndrome and functional impairment in mild Covid-19 out-patients as both of these components may improve with ambulatory rehabilitation.