Search Results (227)

Background/Objectives: Flexible bronchoscopy (FB) enables airway exploration and diagnosis of various respiratory pathologies, but the sedation and instrumentation required during the procedure raise oxygen demand while reducing ventilation, which can lead to hypoxemia. Conventional oxygen therapy (COT) may not adequately prevent desaturations in high-risk groups, as patients with moderate respiratory deficiency. High-flow nasal cannula (HFNC) can deliver heated, humidified oxygen at high flow rates, generating low-level positive airway pressure, improving oxygenation, reducing dead-space, and enhancing procedure tolerance. Prior studies have shown that HFNC can improve gas exchange and reduce desaturations during bronchoscopy. However, evidence remains limited for patients with moderate respiratory deficiency, who are particularly vulnerable. Evaluating the feasibility and safety of HFNC in this population is essential to guide safe procedural practice. Methods: A retrospective observational study including patients undergoing FB with HFNC support between January and May 2025. Inclusion criteria were BMI between 18 and 30; age > 18 years old; moderate respiratory dysfunction, defined by pulse oximetry, Pulmonary Functional Tests (PFTs) and Arterial Blood Gas (ABG) analysis. Exclusion criteria were intolerance/contraindication to HFNC. Procedures were performed under basic monitoring. Primary outcome was occurrence of severe hypoxemia (SpO2 < 90%). Secondary outcomes were needed for rescue maneuvers, interruption for conversion to other ventilatory strategies, and hemodynamic instability. Results: No severe desaturations were recorded, all procedures were completed without rescue maneuvers or other ventilatory strategies, and no hypoxemia occurred. Mean duration of the procedure was 9 min. Vital parameters were maintained within the normal ranges, with a mean SpO₂ during bronchoscopy of 98%. Conclusions: HFNC enables oxygenation and ventilation without adverse events in sedations for FB in patients with moderate respiratory deficiency. Full article

Background: Durvalumab, a PD-L1 inhibitor used as consolidation therapy after chemoradiation in unresectable stage III non–small cell lung cancer (NSCLC), can induce immune-related adverse events, among which immune-mediated pneumonitis represents one of the most severe. Differentiating checkpoint inhibitor pneumonitis (CIP) from infectious pneumonia is challenging due to overlapping clinical and radiologic findings. Case presentation: We describe a 67-year-old woman with stage III lung adenocarcinoma treated with chemotherapy, radiotherapy, and durvalumab, who presented with progressive dyspnea and extensive bilateral ground-glass opacities on CT imaging. Laboratory tests revealed leukopenia and elevated inflammatory markers. Despite broad-spectrum antibiotic and antiviral therapy, her condition worsened, requiring high-flow nasal cannula oxygen therapy. Multiplex molecular testing on sputum identified human metapneumovirus (HMPV), while blood cultures and urinary antigens for Streptococcus pneumoniae and Legionella pneumophila were negative. A pulmonology consultation raised suspicion for severe durvalumab-induced pneumonitis exacerbated by viral infection. High-dose methylprednisolone (2 mg/kg/day) followed by a four-week taper led to gradual clinical and radiologic resolution. Durvalumab was permanently discontinued. Discussion: To our knowledge, this is the first reported case of HMPV-associated pneumonitis in a patient receiving durvalumab. This case highlights the potential synergistic interplay between viral infection and immune checkpoint blockade, resulting in severe lung injury. Comprehensive microbiologic evaluation, including molecular diagnostics, is essential to guide therapy and distinguish infectious from immune-mediated causes. Conclusions: Early recognition of mixed infectious and immune-mediated pneumonitis, and timely corticosteroid therapy are critical to achieving favorable outcomes and preventing irreversible pulmonary damage. Full article

High-flow nasal cannula (HFNC) therapy is frequently described as a positive pressure modality, yet this classification lacks mechanistic support. This critical narrative review integrates experimental, computational, and clinical evidence to examine the established physiological mechanisms underlying HFNC, with emphasis on precise terminology. The study clarifies that labeling HFNC as “positive pressure” is conceptually inaccurate, as the system delivers transient, flow-dependent pressures characteristic of open-circuit administration. Evidence is synthesized to quantify the relative contributions of nasopharyngeal dead-space clearance versus emergent pressure generation. Unlike CPAP, HFNC produces pressures ranging from 0.2 to 13.5 cmH₂O, determined by airway geometry, leak magnitude, and mouth position. Fluid dynamic modeling using Bernoulli and Darcy–Weisbach equations demonstrates oscillatory rather than sustained pressures, with magnitudes linked to nasopharyngeal Reynolds numbers (2400–6000) and turbulent energy dissipation (30–60%). Clinical efficacy persists despite variable pressures, reflecting synergistic mechanisms: inspiratory flow matching (40–50% reduction in work of breathing), dead-space clearance (CO₂ reduction, r = −0.77, p < 0.05), emergent pressure effects (10–20%), and thermal humidification (10–20%). Electrical impedance tomography reveals heterogeneous alveolar recruitment, with high-potential (54%) and low-potential (46%) phenotypes. Based on these mechanistic insights, this review proposes the term “emergent hydrodynamic pressure” to accurately describe HFNC’s transient, flow-dependent pressures. This terminology differentiates HFNC from conventional positive pressure systems and aligns language with the principles of fluid dynamics and respiratory physiology. Full article

Background: Use of high-flow nasal cannula (HFNC) expanded from ICUs to internal medicine/respiratory wards during and after the COVID-19 pandemic, but safety and effectiveness in non-ICU settings remain uncertain. Methods: We performed a systematic review and meta-analysis of adults (≥18 years) initiated on HFNC in non-ICU wards. Primary outcomes were in-hospital (or 28-day) mortality and ICU transfer; where available, we compared mortality for HFNC vs. conventional oxygen therapy (COT) in do-not-intubate (DNI) cohorts. Observational studies and trials were eligible. Random-effects models synthesized proportions and risk ratios; risk of bias (ROBINS-I/RoB 2) and certainty (GRADE) were assessed. Results: Ten studies met the inclusion criteria for any-ward HFNC; subsets contributed data to pooled analyses. Across all non-ICU wards (general wards plus step-up IMCU/HDU), pooled mortality was 14.0% (95% CI 4.6–35.5; I² ≈ 92%). Pooled ICU transfer after ward/step-up HFNC start was 20.0% (95% CI 6.3–48.1; I² ≈ 97%). Restricted to internal medicine/respiratory wards, pooled mortality was 19.8% (95% CI 7.1–44.2; I² ≈ 95%) and ICU transfer 31.2% (95% CI 9.9–65.0; I² ≈ 97%). In step-up units (IMCU/HDU), ICU transfer appeared lower and less variable (22.0% [95% CI 16.5–28.8]; I² ≈ 10%), suggesting environment-dependent outcomes. In a multicenter DNI COVID-19 cohort, HFNC vs. COT showed no clear mortality difference (RR ≈ 0.90, 95% CI 0.75–1.08; adjusted OR ≈ 0.72, 95% CI 0.34–1.54). Certainty of evidence for all critical outcomes was very low due to observational design, high inconsistency, and imprecision. Conclusions: HFNC outside the ICU is feasible, but it is related to nontrivial mortality and frequent escalation—particularly on general wards—while step-up units demonstrate more reproducible trajectories. Outcomes appear strongly conditioned by care environment, staffing, monitoring, and escalation pathways. Given very low certainty and substantial heterogeneity, institutions should pair ward HFNC with protocolized reassessment and rapid response/ICU outreach, and future research should prospectively compare ward HFNC pathways against optimized COT/NIV using standardized outcomes. Full article

Background: Immunocompromised patients, particularly those with humoral immune deficiencies or receiving B-cell-targeted therapies, are at increased risk of persistent SARS-CoV-2 infection, a condition often underrecognized and lacking standardized treatment. Methods: We present a case series of patients with persistent SARS-CoV-2 infection and underlying humoral immunodeficiency, treated at the General University Hospital “Attikon” from February 2023 to September 2024. Persistent infection was defined by prolonged symptoms, compatible imaging findings, and RT-PCR positivity beyond 21 days. All patients received combination antiviral therapy with remdesivir and nirmatrelvir/ritonavir, and intravenous immunoglobulin (IVIG), using a structured diagnostic and therapeutic algorithm. Results: Eleven patients (55% male), median age 56 [IQR 50–66] years, were included. Seven (64%) had hematologic malignancy, 10 (91%) received anti-CD20 therapy, and 6 (55%) had both. Median symptom duration before diagnosis was 63 [58–135] days. Ten (91%) experienced recurrent symptoms; one (9%) had progressive symptoms with severe respiratory failure requiring high-flow nasal cannula. Persistent infection was confirmed via bronchoscopy with bronchoalveolar lavage in 6 patients (55%). Prior to diagnosis, 5 patients (45%) required one hospitalization, 1 (9%) was hospitalized twice, and 2 (18%) had more than two hospitalizations. Following combination therapy, 10 (91%) achieved complete response at 180-day follow-up. Conclusions: The proposed diagnostic and therapeutic algorithm combining remdesivir, nirmatrelvir/ritonavir, and IVIG enhanced diagnostic value and therapeutic outcomes in this high-risk population. Full article

Deep Sedation (DS) allows for shorter recovery times, reduced complication rates and increased cost-effectiveness compared to general anesthesia. In prolonged DS, High Flow Nasal Oxygen Therapy (HFNOT) ensures adequate oxygenation. Concerns remain regarding potential masking of inadequate ventilation and induction of hyperoxia. In this single-center observational study, we continuously monitored tcPCO₂ and mitoPO₂ in 30 patients using the SenTec Monitoring System and Cellular Oxygen METabolism (COMET^®, Photonics Healthcare, Utrecht, The Netherlands) device to observe the effect of prolonged DS with HFNOT on periprocedural ventilation and oxygenation. Measurements were taken at baseline and 30, 60, 90 and 120 min after starting DS. tcPCO₂ significantly increased after 30 (55.5 (34.5–61.9) mmHg, p < 0.001), 60 (54.8 (52.5–62.2) mmHg, p < 0.001), 90 (56.5 (53.1–69.3), p < 0.001) and 120 (55.8 (50.7–56.6) mmHg, p = 0.02) minutes of DS compared to baseline (37.3 (34.5–45.5) mmHg), surpassing the normal range (35–45 mmHg). mitoPO₂ increased non-significantly from baseline (69.6 (43.9–76.7) mmHg) compared to 30 (80.5 (65.7–98.9) mmHg, p = 0.19), 60 (78.6 (70.3–85.8) mmHg, p = 0.19), 90 (74.4 (52.7–86.3) mmHg, p = 0.38) and 120 (85.6 (82.5–98.0) mmHg, p = 0.38) minutes. We observed increased tcPCO₂ and a non-significant rise in mitoPO₂ over time, without adverse effects. These findings highlight the potential of continuous sensor-based monitoring to improve real-time detection of ventilation and oxygenation. Full article

Background and Clinical Significance: Intermediate-high-risk pulmonary embolism is characterized by right-ventricular dysfunction and positive cardiac biomarkers in the absence of hemodynamic instability. Current guidelines recommend anticoagulation with vigilant monitoring, and reserve systemic fibrinolysis for patients who deteriorate hemodynamically. However, some patients may experience physiologic decompensation manifested by refractory hypoxemia rather than hypotension, despite preserved systemic perfusion and normal lung parenchyma. In such cases, oxygenation failure reflects the severity of perfusion impairment and incipient right-ventricular-circulatory collapse. Whether this scenario justifies systemic fibrinolysis remains uncertain. Case Presentation: We present a 75-year-old man, five days after arthroscopic meniscus repair, presenting with acute dyspnea, tachycardia, and severe respiratory failure despite normal chest radiography. Laboratory findings revealed elevated troponin-I and brain natriuretic peptide, and echocardiography demonstrated marked right-ventricular dilation. Computed tomographic pulmonary angiography confirmed extensive bilateral central emboli with preserved lung parenchyma. Despite high-flow nasal oxygen at 100% fraction of inspired oxygen, respiratory failure worsened, necessitating intubation under lung-protective settings. With catheter-directed therapy unavailable and transfer unsafe, a multidisciplinary team administered staged systemic fibrinolysis with alteplase, pausing heparin during infusion. No bleeding or surgical complications occurred. Oxygenation and right-ventricular indices improved promptly. The patient was extubated on day 2, discharged from intensive care unit on day 7, and remained asymptomatic with normal echocardiography at 3 months. Conclusions: Refractory hypoxemia in intermediate-high-risk, normotensive pulmonary embolism, particularly when parenchymal disease and ventilator confounding are excluded, may represent an early form of circulatory decompensation warranting rescue reperfusion. In the absence of catheter-directed options and with acceptable bleeding risk, staged full-dose systemic fibrinolysis can be life-saving and physiologically justified. This case supports expanding the concept of “clinical deterioration” in intermediate-risk pulmonary embolism to include isolated, unexplained respiratory failure, highlighting the need for future trials to refine individualized reperfusion thresholds. Full article

Background: Data on high flow nasal oxygenation (HFNO) efficacy in hypoxia prevention in transcatheter aortic valve replacement (TAVR) are conflictive. We aimed to determine the benefit of HFNO in preventing the occurrence of desaturations during TAVR. Methods: An investigator-initiated, proof of concept, single-centre, randomised, and controlled trial on 132 adult patients who were scheduled to undergo transfemoral TAVR was conducted. Patients were randomised (1:1) to HFNO (H-group) with a flow rate of 50 L min⁻¹ and FiO₂ 0.6 or standard of care oxygen therapy (S-group). The primary endpoint was the number of patients with a desaturation episode (SpO₂ < 93%) for >10 s during TAVR. Secondary outcomes included arterial partial pressure of oxygen (pO₂) 45 min from sedation start and changes in glomerular filtration rate from baseline to 12 h post-procedure. Results: Between 23 November and 24 July, a per-protocol analysis was performed in a total of 125 patients (H-group n = 64; S- group n = 61; 49 females). The number of patients with any desaturation episode was significantly lower in the H-group [13/64 (20%, 95% CI: 12–32%)] than in the S-group [31/61 (51%, 95% CI: 39–63%), RR: 0.39 (95%CI: 0.23–0.68)]. At 45 min, mean (SD) pO₂ was higher in the H-group (24(9.8) kPa vs. 16.7(7.5) kPa; p < 0.005). A significant improvement in delta median (IQR) difference on glomerular filtration rate was observed in the H-group [1.6(−1–7.9) mL min⁻¹ 1.73 m⁻²] with respect to the S-group [0.2(−6.1–3.1) mL min⁻¹ 1.73 m⁻²; p-value: 0.013]. Conclusions: This trial demonstrated that HFNO provides a better oxygenation pattern than standard oxygen therapy during TAVR. Larger studies focusing on long-term clinical outcomes are warranted to evaluate the benefit of HFNO during sedation for TAVR procedures. Full article

The high dimensionality of flow fields obtained from Computational Fluid Dynamics (CFD) poses major challenges for Machine Learning (ML), especially when the scarcity of training data combines with strong geometric variability. Most existing ML approaches for inference from CFD data rely on expert-defined features, primarily quantities computed over manually selected regions. However, this strategy does not scale well, since regions must be redefined for each new geometry, requiring expert knowledge and significant effort. To overcome this limitation, we introduce two complementary methods to extract features from CFD flow fields: the first identifies meaningful flow regions by clustering features derived from the governing equations; the second employs mesh morphing to align each flow field onto a common reference geometry, enabling consistent use of expert-defined regions across cases. Both require minimal human intervention on new samples and ensure scalability across diverse CFD scenarios. We validate our methods on two distinct applications: first, by accurately identifying airfoil shapes and geometric defects; second, by classifying nasal pathologies from 3D CFD simulations of human upper airways reconstructed from CT scans. Both methods show robustness and high accuracy, highlighting their potential for automated, generalizable, and scalable CFD analysis within ML frameworks. Full article

Objectives: This study aimed to evaluate how non-invasive ventilation (NIV) and high-flow nasal cannula therapy (HFT) versus conventional oxygen therapy (COT) affect neural ventilatory drive during exercise in patients with severe chronic obstructive pulmonary disease (COPD). Methods: We conducted an experimental, controlled study with one arm and three different conditions for the same cohort. After initial testing on conventional oxygen therapy (COT), patients exercised under NIV and HFT in sequential days and a random order. Participants: Twenty patients (mean age 60 years old (SD 3.9), 6 female) with severe COPD (30% women) on home NIV as a bridge to lung transplantation were enrolled in this study, with a mean FEV₁ of 19.78% predicted and marked hyperinflation. Protocol: Participants performed constant-load cycling exercises at 75% maximum tolerated workload under three conditions: COT, NIV, and HFT. Neuro-respiratory drive (NRD) was measured using surface parasternal and sternocleidomastoid electromyography, and mixed ANOVA was performed to analyze repeated measures across conditions. Results: In total, 20 patients were included in this study. NIV demonstrated superior performance, with 60% lower NRD compared to COT (488.81 µV vs. 1180.63 µV, p < 0.05). HFT showed intermediate effects (807.8 µV). NIV also achieved greater reduction in respiratory rate (4.2 breaths/min), lower perceived exertion (Borg score decrease: 1.8 points), and more pronounced CO₂ reduction (5.3 mmHg) compared to both COT and HFT. Conclusions: NIV significantly reduces NRD during exercise in severe COPD patients compared to HFT and COT. This supports its use as a valuable adjunct to pulmonary rehabilitation in severe COPD. Full article

Background/Objectives: Rigid bronchoscopy poses safety challenges due to airway leakage. Although apnoeic oxygenation is a potential strategy, concerns over carbon dioxide (CO₂) retention have limited its adoption. The introduction of high-flow nasal cannula (HFNC) has renewed interest by potentially mitigating CO₂ accumulation during prolonged apnoea. This study investigated changes in the arterial partial pressure of CO₂ (PaCO₂) during apnoeic oxygenation using Optiflow™. Methods: We retrospectively analysed patients undergoing rigid bronchoscopy with HFNC (70 L·min⁻¹) from 2020 to 2022. The apnoeic period was defined from the onset of apnoeic oxygenation to ventilation resumption. Arterial blood gas levels and complications, including arrhythmia and desaturation, were evaluated. Regression analysis was used to evaluate changes over time. Results: Apnoeic oxygenation was performed in 10 male patients (mean age 65 ± 14 years; body mass index 24.75 ± 4.18 kg·m⁻²). The mean duration of apnoea was 33.7 ± 13.7 min, with PaCO₂ rising linearly at 1.50 mmHg/min. No interventions were required to maintain SpO₂ above 91% for all patients. Except for one case of atrial fibrillation that occurred during emergence rather than the apnoeic period, no significant complications were observed. Conclusions: The observed increase in PaCO₂ was lower than in previously reported studies using HFNC via the nares, suggesting that direct delivery of oxygen to the distal airway via bronchoscopy may enhance CO₂ clearance through more effective washout. Apnoeic oxygenation with HFNC could potentially overcome airway leakage for selected patients, but vigilant monitoring remains essential throughout the apnoeic period. Further research is warranted to enhance patient safety. Full article

Background/Objectives: Closed-loop automated oxygen control (CLAC) systems improve compliance with oxygen saturation targets and other outcomes in preterm ventilated infants. This narrative review aimed to explore the efficacy of CLAC systems in preterm infants receiving non-invasive respiratory support and identify areas that needed further research. Methods: A literature search was conducted using PubMed. The search terms were ‘closed loop’ or ‘automat*’, ‘oxygen’ and ‘neonat*’. Results: Sixteen studies were identified: twelve randomised crossover studies, three randomised controlled trials (RCTs) and a matched-cohort study. Nine studies included only infants receiving non-invasive respiratory support, and the remaining seven incorporated results from infants either on invasive or non-invasive ventilation. Overall, CLAC was associated with an increased percentage of time spent within the target oxygen saturation range and reduced time spent in extremes of oxygenation (SpO₂ < 80% and SpO₂ > 98%) when compared with manual oxygen control. CLAC was applied in infants receiving different modes of non-invasive respiratory support, including continuous positive airway pressure, high and low-flow nasal cannula oxygen. Some of the studies had limited power as they were prematurely stopped due to recruitment or equipment issues. Study periods were mostly less than or equal to 24 h. There were no data on longer-term clinical outcomes, including bronchopulmonary dysplasia, retinopathy of prematurity, necrotising enterocolitis and mortality. Conclusions: CLAC improves the achievement of oxygen saturation targets in preterm infants receiving non-invasive respiratory support. Future research is needed to explore the effect of CLAC on clinical outcomes in this population. Full article

Background/Objectives: At Fiona Stanley Hospital’s pulmonary rehabilitation program, people awaiting lung transplantation (LTx), whose exertional oxygen requirements are unable to be met with traditional oxygen interfaces, utilize high-flow nasal oxygen (HFNO) to exercise. In this paper, we aim to: (i) describe the characteristics of our service and of the people who have utilized HFNO; and (ii) explore differences between those who survived vs. did not survive whilst awaiting LTx. Methods: We conducted a description of the service and a retrospective analysis (from January 2021 to April 2024). The service description included: facility, equipment/cost, staffing/patient ratio, exercise program characteristics, and safety. Inclusion criteria for the analysis were: people actively listed for LTx and completion of three or more exercise sessions on HFNO. Data extracted included patient characteristics, comorbidities, 6-min walk distance (6MWD) prior to commencing HFNO, and survival pre-LTx. Differences between those who survived vs. did not survive whilst awaiting LTx were explored. Results: Nineteen patients were included (13 males; age 60 ± 12 yr; 18 with interstitial lung disease). The median [IQR] number of exercise sessions on HFNO was 15 [9; 25]. Eight (42%) patients died whilst awaiting LTx. In those who survived, the median time to LTx was 46 [25; 268] days. Compared to those who died, those who underwent LTx had fewer comorbidities (median: 2 [1; 4] vs. 4 [3; 5], p = 0.03). They also tended to be younger and have greater absolute 6MWD prior to commencing HFNO (mean difference, 95%CI: age −8.6 yr, −19.3 to 2.1; 6MWD 55 m, −74 to 185). Associations between dyspnea or body mass index with survival were not demonstrated. This analysis is hypothesis-generating rather than inferential, given the limited sample size. Conclusions: Our unique service of high-flow nasal oxygen (HFNO) use in patients participating in pulmonary rehabilitation whilst awaiting lung transplantation is described. Preliminary analysis suggests that, in people utilizing HFNO whilst awaiting LTx, those who underwent LTx had fewer comorbidities than those who did not survive the waitlist period. Larger studies are needed to explore further differences between those who survive vs. those who do not survive whilst awaiting LTx. Full article

Weaning from invasive mechanical ventilation (IMV) is a key element in the management of critically ill patients, encompassing the entire process of discontinuing IMV. Despite its importance, considerable uncertainties remain regarding the optimal strategies to achieve successful weaning. Early weaning is crucial, as IMV is associated with complications related to high mortality rates, such as prolonged weaning and intubation-associated pneumonia (IAP). This review aims to highlight the role of non-invasive respiratory supports (NIRSs), including non-invasive ventilation (NIV) and high-flow nasal cannulas (HFNCs), as a therapeutic bridge between IMV dependency and spontaneous breathing. NIV and HFNCs are recommended to prevent post-extubation respiratory failure (PERF) in high-risk and low-risk patients, respectively, and their combination appears effective in high-risk populations. On the other hand, NIV is not advised in established non-hypercapnic PERF, as it may increase mortality by delaying intubation; however, it can facilitate extubation in patients with hypercapnic respiratory failure. NIRSs may also benefit patients at high risk of post-operative pulmonary complications such as acute respiratory failure (ARF), with either NIV or HFNCs being appropriate. In light of this evidence, appropriate NIRSs selection and application may be pivotal in achieving successful weaning and better outcomes in critically ill patients. Full article

The SARS-CoV-2 pandemic presents a broad clinical spectrum from asymptomatic cases to severe respiratory failure with high mortality. Severe COVID-19 is characterized by immune dysregulation, including lymphopenia and alterations in the counts of T, B, and NK cells in peripheral blood. Due to the limited data on long-term outcomes related to immune dysregulation, we aimed to analyze immunologic features at baseline in severe and mild COVID-19 cases and assess follow-up characteristics associated with later mortality and long-COVID signs. We included adult patients consecutively hospitalized with COVID-19 between June and November 2020 at the University Hospital in Kraków, corresponding to the first and second waves of COVID-19 in Poland. We enrolled only those who had been thoroughly assessed in terms of clinic and laboratory data, including immunological workups, and survived the acute phase of the disease. In 2025, between February and April (median time of follow-up: 54 months), we conducted a telephone questionnaire on long-COVID symptoms among survivors who had given their consent. Statistical analyses were performed to compare groups with severe and mild disease in terms of dysregulation in lymphocyte subpopulations and the follow-up outcomes. The study included 103 COVID-19 patients, comprising 53 severe (based on the need for at least high-flow nasal oxygen therapy) and 50 mild cases, with no differences in age, sex, and body mass index. Severe COVID-19 patients compared to mild cases had lower CD3+ T cells (count and percentage), CD4+ T cells (count and percentage), CD8+ T cells (count), and NK cells (count), but higher CD19+ B cells (percentage) at baseline (p < 0.05, all). At the time of follow-up, we evaluated 80 patients (77.7% of the baseline participants), with 23 (22.3%) patients lost to follow-up. Among patients analyzed in the follow-up, 23 (28.8%) had died, and 29 of the 57 survivors (50.9%) reported persistent long-COVID symptoms. Patients who died had significantly lower baseline counts of CD3+ T cells (377 vs. 655 cells/µL), CD4+ T cells (224 vs. 372 cells/µL), CD8+ T cells (113 vs. 188 cells/µL), and NK cells (118 vs. 157 cells/µL) compared to survivors (p < 0.05, all). Notably, the percentage of CD19+ B cells was higher in deceased individuals (19.2% vs. 13.5%; p = 0.049). In contrast, we did not document differences in baseline immunological data among survivors with and without long-COVID signs. Our study suggests that dysregulation in lymphocyte subpopulations during the COVID-19 acute phase may be associated with increased late mortality, but not with the persistence of long-COVID symptoms. Full article