Acute hypercapnic dyspnea and SARS-COV2 infections in hemodialysis patients treated with AFB

Background: Dialysis treatment in chronic obstructive pulmonary disease (COPD) patients is a challenging setting: COPD frequently develop hypercapnia due to presence of CO2 that originates from the reaction between acetic/citric acid with bicarbonate, needed to prevent the precipitation of salts inside. Carbon dioxide passes through the dialysis membrane by diffusion, because of the significant difference in partial pressure between the dialysate compartment (80-100 mmHg) and the blood compartment (35-45 mmHg) thus determining CO2 overload. A COPD patient, on the other hand, may not be able to implement effective respiratory compensation mechanisms with the consequent onset of hypercapnia. Method(s): A 79-year-old ESRD patient was admitted because of SARS-CoV2 infection. His medical history was notable for emphysematous COPD with predominantly severe obstructive disorder on chronic oxygen therapy. The patient present acute hypercapnic dyspnea during the first dialysis session in COVID19 setting with severe desaturation episode associated with mixed acidosis (pH 7.13, pCO2 83 mmHg, HCO3- 22.7 mmol/l). The raise of pCO2 was remarkable, in fact partial pressure of CO2 (pCO2) was 61 mmHg before dialysis versus pCO2 83 mmHg after dialysis treatment (Fig.1). The patient appeared comatose and poorly responsive to stimuli. CPAP cycle was set up and he was placed in semi-orthopneic decubitus did not improve the clinical conditions. To prevent the hypercapnia condition Acetate Free Biofiltration (AFB) technique with profiled potassium (K+ 3.5 mmol/L) was prescribed. The vital parameters during this hemodialysis session remained stationary and the pCO2 values at the end of dialysis were comparable to those at the beginning of dialysis (pCO2 65 mmHg versus a.d. pCO2 63 mmHg) (Fig. 1). The following treatment were well tolerated with progressive improvement of respiratory parameters. Result(s): The AFB technique is characterized by a dialysate without buffers which do not react and do not produce carbon dioxide. The correction of the acid-base balance takes place with the post-dilution infusion of a sterile solution of sodium bicarbonate (NaHCO3). Furthermore, the absence of acetic acid avoids the stimulation of interleukin 1beta (IL-1beta) and of the Tumor Necrosis Factor alpha (TNFalpha) which in turn would have activated the enzyme Nitric Oxide Synthetase (iNOS) thus causing an increased production of Nitric Oxide (NO) and a consequent greater hemodynamic instability. AFB is therefore a more tolerated technique from a hemodynamic point of view. Conclusion(s): This case report has shown that AFB is an effective hemodialysis technique in preventing a condition of hypercapnia in patients suffering from respiratory diseases (Fig.2). The patient also experienced hemodynamic stability from the AFB with no longer presenting significant hypotensive episodes.

Evaluation of Anti-SARS-CoV-2 IgG before and after vaccination in subjects with and without previous COVID-19 disease

BACKGROUND-AIM Although more than two years have passed since the beginning of the SARS-CoV-2 pandemic, the interest of Public Health in the development and administration of effective anti-COVID-19 vaccines continues.We aimed to test the antibody response to SARS-CoV-2 vaccination in patients with and without previous infection. METHODS From June 2021 to November 2021, we recruited 203 patients who were going to receive vaccination against SARS-CoV-2: 123 women (60.6%) with a median age of 44 years (IQR: 33-56) and 80 men (39.4%) with a median age of 43 years (IQR 32-53);78 patients reported previous SARS-CoV-2 infection (41 women, 37 men). 74 out of 203 were healthy subjects, 84 reported mild to medium allergic history and 45 other diseases. 97.4% of subjects received BioNTech/Pfizer vaccination and, according to Ministerial Dispositions, patients with previous SARS-CoV-2 infection received a single dose (group 1), other patients received two (group 2). After 3 months, 98 subjects received a third dose (57 BioNTech/Pfizer and 41 half a dose of Spikevax-Moderna).The antibody response to vaccination was measured on blood samples collected before vaccination (T0), 10 days after the first dose of vaccination (T10), 15 (T15), 90 (T90) and 180 (T180) days after the second or only vaccination. Samples were tested using Access SARS-CoV-2 IgG (1st IS) on Access UniCelDxI 800 (Beckman Coulter s.r.l.). RESULTS The comparison between median concentrations in our groups showed a statistically significant difference (p<0.001) at T0, T15 and T90, but not at T180 (p=0.713). At T0 and T90 the SARS-CoV-2 IgG concentration was higher in group 1, while at T15 it was higher in group 2. At T90 the antibody titer dropped in all patients, but the decrease was higher in group 1. 77 SARS-CoV-2 infections occurred after vaccination (4.2% between T15 and T90, 95.7% between T90 and T180). CONCLUSIONS We confirm that the antibody titer is significantly associated with a having had previous SARSCoV-2 infection, but not with age and sex. The probability of contracting the infection after vaccination increases after three months from primary vaccination, confirming the efficacy of vaccination as a preventive measure against SARS-CoV-2 infections and the need of booster administrations.

Metabolic correlates of olfactory dysfunction in covid-19 and Parkinson's disease (PD)

Background-Aim: A potential link has been investigated between hyposmia after COVID-19 and an increased risk to develop neurological long-term sequelae also in patients who experienced mild or moderate disease. Hyposmia is a common feature PD and parkinsonism has been reported after COVID-19 suggesting a potential link between SARS-CoV2 infection and PD. [18F]FDG PET may represent a suitable tool to capture potential common metabolic signature of hyposmia after COVID-19 and in PD patients. We aimed to evaluate brain metabolic correlates of isolated persistent hyposmia after mild-to-moderate COVID-19 and to compare them with metabolic signature of hyposmia in drug-naive PD patients. Methods: Forty-four patients who experienced hyposmia after SARSCOV2 infection underwent brain [18F]FDG-PET in the first 6 months after recovery. Olfaction was assessed by means of the 16-item ''Sniffin-Sticks'' test and patients were classified as with or without persistent hyposmia (COVID-hyposmia and COVID-no-hyposmia respectively). Brain [18F]FDG-PET of post-COVID subgroups were compared in SPM12. COVID-hyposmia patients were also compared with eighty-two drug-naïve PD patients with hyposmia. Multiple-regression- analysis was used to identify correlations between olfactory test-scores and brain metabolism in patients' subgroups. Results: COVID-hyposmia patients (n = 21) exhibited significant hypometabolism in bilateral gyrus rectus and orbitofrontal cortex with respect to COVID-non-hyposmia (n = 23) (p<0.002) and in middle and superior temporal gyri, medial/middle frontal gyri and right insula with respect to PD-hyposmia (p<0.012). With respect to COVIDhyposmia, PD-hyposmia patients showed hypometabolism in inferior/ middle occipital gyri and cuneus bilaterally. Olfactory test-scores were directly correlated with metabolism in bilateral rectus and medial frontal gyri and in right middle temporal and anterior-cingulate gyri in COVID-hyposmia patients (p<0.006) and with bilateral cuneus/precuneus and left lateral occipital-cortex in PD-hyposmia patients (p<0.004). Conclusions: Metabolic signature of persistent hyposmia after COVID-19 encompasses cortical regions involved in olfactory perception and does not overlap metabolic correlates of hyposmia in PD. An impairment in olfactory judgement seem to underlie hyposmia in PD patients while a more restricted perception deficit seems to explain hyposmia in COVID-19. The potential long term neurological sequelae of COVID-19 are of interest from the clinical and economical point of view. Studies targeting symptoms common to COVID-19 and chronic neurological diseases and aiming to explore potential common pathways are of interest also to avoid unjustified claims about a future high incidence of neurodegenerative diseases secondary to the SARS-CoV-2 pandemic.

Hierarchical convolutional models for automatic pneu-monia diagnosis based on X-ray images: new strategies in public health.

Conclusions: Despite some limits, our findings support the notion that deep learning methods can be used to simplify the diagnostic process and improve disease management. Background: In order to help physicians and radiologists in diagnosing pneumonia, deep learning and other artificial intelligence methods have been described in several researches to solve this task. The main objective of the present study is to build a stacked hierarchical model by combining several models in order to increase the procedure accuracy. Methods: Firstly, the best convolutional network in terms of accuracy were evaluated and described. Later, a stacked hierarchical model was built by using the most relevant features extracted by the selected two models. Finally, over the stacked model with the best accuracy, a hierarchically dependent second stage model for inner-classification was built in order to detect both inflammation of the pulmonary alveolar space (lobar pneumonia) and interstitial tissue involvement (interstitial pneumonia). Results: The study shows how the adopted staked model lead to a higher accuracy. Having a high accuracy on pneumonia detection and classification can be a paramount asset to treat patients in real health-care environments.

Age is not the only risk factor in COVID-19: the role of comorbidities and of long staying in residential care homes.

BACKGROUND: The actual SARS-CoV-2 outbreak caused a highly transmissible disease with a tremendous impact on elderly people. So far, few studies focused on very elderly patients (over 80 years old). In this study we examined the clinical presentation and the outcome of the disease in this group of patients, admitted to our Hospital in Rome. METHODS: This is a single-center, retrospective study performed in the Sant'Andrea University Hospital of Rome. We included patients older than 65 years of age with a diagnosis of COVID-19, from March 2020 to May 2020, divided in two groups according to their age (Elderly: 65-80 years old; Very Elderly > 80 years old). Data extracted from the each patient record included age, sex, comorbidities, symptoms at onset, the Pneumonia Severity Index (PSI), the ratio of the partial pressure of oxygen in arterial blood (PaO2) to the inspired oxygen fraction (FiO2) (P/F) on admission, laboratory tests, radiological findings on computer tomography (CT), length of hospital stay (LOS), mortality rate and the viral shedding. The differences between the two groups were analyzed by the Fisher's exact test or the Wilcoxon signed-rank test for categorical variables and the Mann-Whitney U test for continuous variables. To assess significance among multiple groups of factors, we used the Bonferroni correction. The survival time was estimated by Kaplan-Meier method and Log Rank Test. Univariate and Multivariate logistic regression were performed to estimate associations between age, comorbidities, provenance from long-stay residential care homes (LSRCH) s and clinical outcomes. RESULTS: We found that Very Elderly patients had an increased mortality rate, also due to the frequent occurrence of multiple comorbidities. Moreover, we found that patients coming from LSRCHs appeared to be highly susceptible and vulnerable to develop severe manifestations of the disease. CONCLUSION: We demonstrate that there were considerable differences between Elderly and Very Elderly patients in terms of inflammatory activity, severity of disease, adverse clinical outcomes. To establish a correct risk stratification, comorbidities and information about provenience from LSRCHs should be considered.