A Novel Multi-Parameter Calibrator for Ventilator Tester Based on Reciprocating Plunger

Ventilators are widely needed when the COVID-19 is a global outbreak, and they are used to provide mechanical ventilation for patients who are physically unable to breathe, or breathe insufficiently. A ventilator tester is an instrument used to verify and calibrate ventilation parameters of ventilators like gas flow, tidal volume, frequency. As a measuring device, the ventilator tester also needs to be calibrated periodically. And different parameters are usually calibrated with different devices. In order to improve calibration efficiency and accuracy, a novel multi-parameter calibrator for ventilator tester based on reciprocating plunger is proposed in this work. The system composition is introduced and mathematical models are deduced. According to calibrating regulation, different calibrating modes are simulated and realized. © FLOMEKO 2022.All rights reserved

Scientific rationale of Indian AYUSH Ministry advisory for COVID-19 prevention, prophylaxis, and immunomodulation

The current outbreak of COVID-19 is caused by the SARS-CoV-2 virus that has affected > 210 countries. Various steps are taken by different countries to tackle the current war-like health situation. In India, the Ministry of AYUSH released a self-care advisory for immunomodulation measures during the COVID-19 and this review article discusses the detailed scientific rationale associated with this advisory. Authors have spotted and presented in-depth insight of advisory in terms of immunomodulatory, antiviral, antibacterial, co-morbidity associated actions, and their probable mechanism of action. Immunomodulatory actions of advised herbs with no significant adverse drug reaction/toxicity strongly support the extension of advisory for COVID-19 prevention, prophylaxis, mitigations, and rehabilitation capacities. This advisory also emphasized Dhyana (meditation) and Yogasanas as a holistic approach in enhancing immunity, mental health, and quality of life. The present review may open-up new meadows for research and can provide better conceptual leads for future researches in immunomodulation, antiviral-development, psychoneuroimmunology, especially for COVID-19.Copyright © 2021, Institute of Korean Medicine, Kyung Hee University.

Clinical characteristics and risk factors of patients with COVID-19 developing barotrauma

Background: At our hospital, people with COVID-19 (coronavirus disease 2019) had a high rate of pulmonary barotrauma. Therefore, the current study looked at barotrauma in COVID-19 patients getting invasive and non-invasive positive pressure ventilation to assess its prevalence, clinical results, and features. Methodology: Our retrospective cohort study comprised of adult COVID-19 pneumonia patients who visited our tertiary care hospital between April 2020 and September 2021 and developed barotrauma. Result(s): Sixty-eight patients were included in this study. Subcutaneous emphysema was the most frequent type of barotrauma, reported at 67.6%;pneumomediastinum, reported at 61.8%;pneumothorax, reported at 47.1%. The most frequent device associated with barotrauma was CPAP (51.5%). Among the 68 patients, 27.9% were discharged without supplemental oxygen, while 4.4% were discharged on oxygen. 76.5% of the patients expired because of COVID pneumonia and its complications. In addition, 38.2% of the patients required invasive mechanical breathing, and 77.9% of the patients were admitted to the ICU. Conclusion(s): Barotrauma in COVID-19 can pose a serious risk factor leading to mortality. Also, using CPAP was linked to a higher risk of barotrauma.Copyright © 2021 Muslim OT et al.

Characteristics, management and outcomes of thirty COVID-19 ARDS patients supported with veno-venous extracorporeal membrane oxygenation at Rikshospitalet, Oslo University Hospital

Background: We reviewed patients with COVID-19 ARDS managed with VV-ECMO support at our center from March 2020 until February 2022. Material(s) and Method(s): We extracted data from electronic health records (Metavision and DIPS). We registered premorbid health status, ventilator-settings before initiation of ECMO, the time-course, and hospital mortality. Result(s): Thirty patients were managed at our hospital, with a median age of 57.2 years (28-65) and median BMI 28 (22-40). No patient had any serious comorbidity. Twenty-two patients received non-invasive ventilation prior to intubation (1-10 days). The median time on ventilator were 8.0 days (1-19) prior to ECMO and median tidal volume was 5.8 mL/kg PBW (3.1-7.5). Hypoxemia (median PaO2-FiO2 ratio 8 kPa, range 6-12 kPa) and hypercapnia (median PaCO2 11.9 kPa, range 4.2-18.5) [SEP1] despite lung protective ventilation were the main indications for VV-ECMO. Two patients had severe respiratory acidosis without hypoxemia. 18 patients developed serious complications while managed with ECMO (acute renal failure, clinically significant bleeding, sepsis, right ventricular heart failure, dislocation of cannulae). Seven patients received renal replacement therapy. Sixteen patients (53%) died. Thirteen patients (43%) died on ECMO, three (10%) after weaning, Twelve (40%) were discharged from hospital, two are currently in ICU (7%). The median duration of ECMO and ventilator treatment, was 27 (6-50) and 37 (9-78) days, respectively. Conclusion(s): Management of patients with COVID-19 ARDS with VV-ECMO is very resource-intensive, and accompanied by serious complications and high mortality. In-hospital mortality in our cohort was 53%, which is comparable with reports from other centers. However, the duration of ECMO, and pre-ECMO mechanical ventilation, were longer than typically reported.

Mechanical Ventilation in ARDS

Acute respiratory distress syndrome (ARDS) is a form of hypoxemic respiratory failure, which requires supplemental oxygen delivered by mechanical ventilation, either noninvasively or more commonly by invasive mechanical ventilation. Although not currently meeting the definition for ARDS, these patients may also use heated high-flow nasal cannula and can sometimes avoid invasive mechanical ventilation as a result. The avoidance of worsening acute lung injury using lung-protective ventilation is the first principle of invasive mechanical ventilation in these patients. Conventionally, this involves keeping the plateau pressure below 30 cm H2O by using low tidal volume ventilation, based on ideal body weight. Multiple observational series suggest that targeting a low driving pressure concurrently is also important. The determination of the optimal setting for positive end-expiratory pressure (PEEP) remains controversial. The mode of ventilation utilized may be either volume or pressure limited. It has been suggested that vigorous respiratory efforts can worsen lung injury and are best avoided whenever possible. Modes of ventilation such as airway pressure release ventilation lack evidence to support use and should not be used. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2022.

Demonstration of Remote Control of Critical Care Ventilators and the Integrated Clinical Environment

Introduction: The COVID-19 pandemic posed numerous challenges to patient care, including extensive PPE use, patient care in isolation rooms, inadequate numbers of intensivists particularly in rural communities, use of unfamiliar ventilators that would be partially remedied by the ability to remotely control lung ventilation. The goals of the project were to study the intended use, risk management, usability, cybersecurity for remote control of ventilators and demonstrate the use of a single interface for several different ventilators. Method(s): Clinical scenarios were developed including remote control of the ventilator from an antechamber of an isolation room, nursing station within the same ICU, and remote control from across the country. A risk analysis and was performed and a risk management plan established using the AAMI Consensus Report--Emergency Use Guidance for Remote Control of Medical Devices. A cybersecurity plan is in progress. Testing was done at the MDPNP laboratory. We worked with Nihon Kohden OrangeMed NKV-550, Santa Ana, CA, and Thornhill Medical MOVES SLC, Toronto, Canada. Both companies modified their devices to allow remote control by and application operating on DocBox's Apiary platform. Apiary is a commercially available ICE solution, DocBox Inc, Waltham, MA. An expert panel was created to provide guidance on the design of a single common, simple to use graphical user interface (GUI) for both ventilators. Manufacturers' ventilation modes were mapped to ISO 19223 vocabulary, data was logged using ISO/IEEE 11073-10101 terminology using AAMI 2700-2-1, Medical Devices and Medical Systems - Essential safety and performance requirements for equipment comprising the patient-centric integrated clinical environment (ICE): Part 2-1: Requirements for forensic data logging. Result(s): We demonstrated that both ventilators can be controlled and monitored using common user interface within an institution and across the country. Pressure and flow waveforms were available for the NKV-550 ventilator, and usual ventilator measurements were displayed in near-real time. The interface allowed changing FiO2, ventilation mode, respiratory rate, tidal volume, inspiratory pressure, and alarm settings. At times, increased network latency negatively affected the transmission of waveforms. Conclusion(s): We were able to demonstrate remote control of 2 ventilators with a common user interface. Further work needs to be done on cybersecurity, effects of network perturbations, safety of ventilator remote control, usability implications of having a common UI for different devices needs to be investigated.

Tracheoesophageal Fistula Presenting With Gastrostomy Tube Pressurization

Introduction: Patients with COVID pneumonia who require intubation and prolonged mechanical ventilation are at risk for complications such as recurrent infection, tracheomalacia, tracheal stenosis, and the development of tracheoesophageal fistula (TEF). TEF is a devastating complication where the trachea and esophagus develop an abnormal connection in the lower airway that dramatically increases the mortality of critically ill patients by recurrent aspiration and pneumonias. Though commonly associated with neoplasms another risk is pressure induced ischemia of the common wall between the trachea and esophagus. This can occur due to overinflation of the endotracheal (ET) cuff, especially with concomitant use of a nasogastric tube (NGT). Definitive management requires surgical repair. Case Description/Methods: A 69-year-old male patient presented with acute hypoxemic respiratory failure secondary to COVID pneumonia requiring intubation and insertion of an NGT. On day 29 the patient underwent percutaneous enterogastrostomy (PEG) placement and tracheostomy;it was noted intraoperatively that the tracheal mucosa was inflamed and friable. On day 36 bronchoscopy was performed through the tracheostomy tube due to concerns for mucus plugging. Friable mucosa with granulation tissue was seen at the distal end of the tube, so an extra-long tracheostomy tube was exchanged to bypass the granulation tissue. Later that night the ventilator measured a 50% discrepancy between the delivered and exhaled tidal volumes, triggering an alarm. Exam noted distension of the PEG-bag with a fluid meniscus in the tubing moving in sync with each respiration. TEF was considered and bronchoscopic evaluation confirmed a 1-centimeter TEF. The patient underwent successful TEF repair and is slowly recovering (Figure). Discussion(s): Critically ill patients who require prolonged support are at high risk of complications and device related injury. With each device-day there is an increased risk of complications, such as infection, dislodgement, and pressure-related injuries. This case highlights the importance of serial physical examinations as well as understanding possible device related complications. An unexpected finding, such as a persistent air leak, air in a PEG bag, or a fluctuating meniscus should raise suspicion for the development of a serious complication and would warrant prompt confirmatory testing. Our literature review revealed no reports of a PEG tube abnormalities as a presenting finding for TEF.

Invasive Mechanical Ventilation in COVID-19

Patients with severe COVID-19 pneumonia present with severe hypoxemic respiratory failure, typically meet the clinical criteria for acute respiratory distress syndrome (ARDS) and often require invasive mechanical ventilation. While peculiar pathophysiological aspects deserve discussion to better tailor the mechanical ventilation settings in these patients, most recommendations on the ventilatory management of these patients are derived from studies in patients with ARDS from causes other than COVID-19. Protective ventilation is recommended in most COVID-19 patients, tidal volume should be kept around 6 mL per kg of predicted body weight, positive end-expiratory pressure (PEEP) should be titrated individually considering that in many patients with COVID-19 improvement of oxygenation at higher PEEP is often accompanied by worsening of respiratory system compliance. Therefore, attention should be paid in limiting plateau and driving pressures to avoid excessive strain potentially resulting in ventilator-induced lung injury. Prone positioning has been used extensively in COVID-19 patients, but its impact on mortality is uncertain. Inhaled nitric oxide, extracorporeal CO2 removal (ECCO2R), and extracorporeal membrane oxygenation (ECMO) should be considered in selected patients as rescue measures. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2022.

VentConnect: telemetry system that enables remote live transmission of ventilator screen: qualitative study of clinicians' expectations and experience

Introduction: To maximise the input of intensivists onto the management of ventilated patients during the COVID pandemic, we have developed and implemented telemetry system VentConnect [1]. The aim of this study is to identify stakeholder's expectations and experience from this technology. Method(s): The telemetry device VentConnect (scheme at Fig. 1) enabled transmission of HDMI signal from mechanical ventilators to a password protected interface on any web browser. We implemented it between December 2020 and March 2021 on a total of 31 beds where patients were treated during COVID Pandemic. Afterwards, we performed Structured User Interviews with ICU doctors. Questionnaire responses we clustered and calculated. Result(s): Eight doctors were interviewed, 4 fully qualified intensivists, and 4 in training. By far the most demanded was the ability to see flow curve or flow pattern (100%), followed by inspiratory pressures (75%) and check tidal volume (63%). Other parameters were mentioned less frequently such as driving pressure (25%) and interferences (38%). With regards users experience, answers were overwhelmingly positive, highlighting mostly the ability to continuously monitor the progress of patients without the need to donning personal protective equipment. In some, however, curiosity was the only motivator for use. Three juniors expressed apprehension that their supervisors might criticise their ventilator setting which would otherwise had gone unnoticed. Two participants thought that the temptation to check patient 24/7 would impair their ability to rest and relax during their off time. Conclusion(s): Telemetry system that enabled clinicians to remotely check ventilator screen met the expectation of clinicians, who mainly demanded to check flow patterns, tidal volumes and pressures. Concerns were mainly about psychological impact of using this technology. These need to be addressed.

Ventilator management and risk of air leak syndrome for patients with COVID-19 pneumonia

Introduction: Coronavirus disease 2019 (COVID-19) pneumonia is reportedly associated with air leak syndrome (ALS), including mediastinal emphysema and pneumothorax, and has a high mortality rate. In this study, we compared values obtained every minute from the ventilator to clarify the relationship between ventilatory management and the risk of developing ALS. Method(s): This was a single-center, retrospective, observational study for a 21-months period. Patient background, ventilator data, and outcomes were collected from adult patients with COVID-19 pneumonia on ventilator-assisted respiratory management. The primary outcome was the development of ALS within 30 days of starting ventilator management. Result(s): Of the 105 patients, 14 (13%) developed ALS. The mean positive-end expiratory pressure (PEEP) difference was 0.33 cmH2O (95% confidence interval (CI) 0.31-0.33), and it was higher in the ALS than in the non-ALS group (9.18 +/- 2.20 versus 8.85 +/- 2.63, respectively). For peak pressure, the mean difference was -0.18 cmH2O (95% CI -0.20 to -0.15), (20.70 +/- 5.30 vs. 20.87 +/- 5.65) and the mean pressure difference of -0.05 cmH2O (95% CI -0.04 to -0.07) (12.80 +/- 3.13 vs. 12.85 +/- 3.55, respectively) was also higher in the non-ALS group. The difference in the single ventilation volume per ideal body weight was 0.65 ml/kg (95% CI 0.63-0.66) (7.83 +/- 3.16 vs. 7.18 +/- 2.96, respectively), and the difference in dynamic lung compliance was 8.57 mL/cmH2O (95% CI 8.43-8.70) (50.32 +/- 31.68 vs. 49.68 +/- 15.16, respectively), and both were higher in the ALS group. The percentage of times that the ventilation volume per body weight exceeded 8 was higher in the ALS group (53.7% vs. 38.6%, p < 0.001). Conclusion(s): There was no association between higher ventilator pressures and the development of ALS. The ALS group had higher dynamic lung compliance and higher tidal volumes, which may indicate a pulmonary contribution to ALS, and ventilatory management that limits tidal volume may prevent the development of ALS.

Tidal volume measurement during non-invasive respiratory support by helmet continuous-flow CPAP is feasible and accurate in a bench model

Introduction: We investigated a novel technique designed to measure tidal volume during non-invasive helmet continuous-flow CPAP, a device for non-invasive respiratory support largely used during the recent COVID-19 pandemic to treat acutely ill hypoxic respiratory failure patients. Method(s): An active lung simulator coupled with a helmet CPAP was used to compare measured and Reference tidal volumes at PEEP 5, 10 and 15 cmH2O and different levels of distress (pMusc 10, 15 20 and 25 cmH2O;respiratory rate 15, 20, 25 breaths per minutes). Tidal volume measurement was based on helmet outflow-trace analysis. Helmet inflow was increased from 60 to 75 and 90 L/min to match patients' inspiratory flow;an additional subset of tests was conducted in condition of purposely insufficient inflow (i.e.: high respiratory distress and 60 L/min inflow). Result(s): Explored tidal volumes ranged from 250 to 910 mL. The Bland-Altman analysis showed a bias of -3.2 +/- 29.3 mL for measured tidal volumes as compared to Reference, corresponding to an average relative error of -1 +/- 4.4% (see Fig. 1). At univariate analyses, tidal volume underestimation correlated with respiratory rate (rho = .411, p = .004) but not with peak inspiratory flow, distress, or PEEP. When the helmet inflow was purposely maintained insufficient as compared to the simulated inspiratory flow, the Bland-Altman analysis showed a significant tidal volume underestimation (bias -93.3 +/- 83.9 mL), corresponding to an error of -14.8 +/- 6.3%. Conclusion(s): We showed that tidal volume measurement is feasible and accurate in a model of bench continuous-flow helmet CPAP therapy by the analysis of the outflow signal, provided that helmet inflow is maintained adequate to match patient's inspiratory efforts. Insufficient inflow resulted in tidal volume underestimation.

42nd International Symposium on Intensive Care and Emergency Medicine

The proceedings contain 369 papers. The topics discussed include: effective FiO2 delivered by a new frugal CPAP system with low oxygen needs: from bench to clinical observations;effect of non invasive respiratory support on interstitial lung disease with acute respiratory failure: a systematic review and meta analysis;causes of mortality of severe COVID 19 patients receiving high flow oxygen therapy;patient ventilator interaction during noninvasive ventilation with helmet: a comparison between pressure support ventilation and the new neural pressure support (NPS) software;tidal volume measurement during non invasive respiratory support by helmet continuous flow CPAP is feasible and accurate in a bench model;delayed intubation with high flow nasal cannula in COVID: a comparison between a first and second pandemic wave;outcomes following application of high flow nasal cannula and non invasive ventilation during the second COVID 19 wave in Singapore;ventilator avoidance among critically ill COVID 19 patients with acute respiratory distress syndrome;and mortality rate, intensive care unit length of stay and time to orotracheal intubation of COVID 19 patients under different non invasive ventilatory therapies: retrospective cohort study.

Prone Ventilation in Patients with Ards

Introduction: Prone ventilation has been a a tool that has been shown to improve oxygenation and ventilatory mechanics in patients with Down syndrome acute respiratory distress (ARDS). Although be a technique that has been performed for decades in the field of intensive care has been with the pandemic generated by COVID-19 when it has returned to be in the spotlight. However, the lack of standardized protocols make it difficultestablish when ventilation should be performed in the prone position, so this little review tries to outline some indications of when it should be done. Methodology: Two recent meta-analyses have been reviewed. about the effects of prone ventilation based on randomized controlled clinical trials of ventilation in the prone position. Result(s): The results of the meta-analyses show that there are certain circumstances which must be given to maximize the beneficial effect of pronation and that it has a beneficial effect on survival of patients with ARDS. First of all, when separated the groups according to whether they had performed lung-protective ventilation or not, the OR of the group prone was 0.58 (95% CI 0.38-0.87) and 0.70 (95% CI 0.47-1.04), so prone ventilation does achieve a decrease in mortality when it is associated with lung-protective ventilation. Another variable that observed in this meta-analysis was the length of time prone, since when this was greater than 12 hours a day the OR of the prone group in terms of mortality vs. supine was 0.60 (95% CI 0.43-0.83) and 0.74 (95% CI 0.56-0.99). When the time was less than 12 hours these beneficial effects on mortality are they dissipated Thirdly, the "timing" was also studied. Of pronation since when it was established in the first 48 hours after ARDS diagnosis, the OR was 0.49 (95% CI 0.35-0.68), beneficial effect that was lost when it started after the first 48 hours. Finally, the severity of ARDS was also assessed (measured in PaFi), observing that patients with severe ARDS (PaFi < 100) achieved a decrease in mortality with an OR of 0.51 (95% CI 0.36-0.72), and this effect the benefit was not achieved in moderate ARDS (PaFi 100-200). The second meta-analysis shows results similar, although this compares the mortality of Moderate-severe ARDS (PaFi <200) with the rest of ARDS, obtaining a reduction in mortality With an OR 0.74 (95% CI 0.56-0.99) Conclusion(s): Prone ventilation can have effects beneficial in the survival of patients with ARDS and it is important to know what conditions you should to have to achieve this effect. If we rely on the results of the latest meta-analyses, it should be recommended its use in patients with moderate-severe ARDS (PaFi < 200), associated with low tidal volumes (ventilation of lung protection with VC < 8cc/kg of ideal weight), for more than 12 hours a day and establishing it in the first 48 hours from the diagnosis of ARDS.Copyright © 2022

Every breath you take, we'll be watching you!

Background: Children and young people (CYP) receiving long term ventilation (LTV) need regular cardiorespiratory sleep studies (CRSS) for management. COVID-19 pandemic restrictions necessitated increased at-home monitoring. Home ventilators have downloadable data which could provide useful insight into ventilation adequacy. We share our preliminary experience with use of downloaded ventilator data to manage LTV patients. Aim(s): Ventilator data from CYP receiving LTV was analysed. We hypothesised that detailed analysis of this data could assist clinical decision making. Method(s): 2-year ventilator download data (ResScan software, ResMed Sleep Solutions, UK) was retrospectively reviewed. Parameters included oxygen saturations, ventilator usage, pressure, air flow and leak. Respiratory rate and tidal volume helped calculate minute ventilation. "Breath-by breath' data was analysed by sleep physiologist and detailed report was provided for clinician review. Result(s): 95 ventilator downloads (36 BIPAP/ 59 CPAP) were analysed in 81 CYP. Poor ventilator adherence was identified in 11/95 (12%). Interface / mask issues were identified in 12/95 (13%). Further CRSS was required in only 4 cases (3%) and clinical interpretation was possible in the remainder. As a result, ventilation parameters were weaned in 17, increased in 5 and unchanged in rest. Conclusion(s): Detailed analysis of ventilator data was sufficient to permit clinical decision making in majority of CYP receiving LTV during the pandemic. It provides valuable information about adherence, interface issues and ventilation for management of these patients. Further validation of this methodology against existing CRSS techniques and to evaluate its role as a stand-alone investigation would be required.

Designing Hybrid Mechanical Ventilator System Based on Arduino and Raspberry Pi 4

Mechanical ventilators are advanced life-supporting machines in this century. The ventilator needs to be safe, flexible, and easy for competent clinicians to use. Since ventilators supply the patient with gas, they need pneumatic components to be present. First technology ventilators were typically powered by pneumatic energy. Gas pressure is used to power ventilators as well as ventilate patients. Nowadays, ventilators are operated electronically with the useful microprocessor tool. This proposal aims to design a simple portable mechanical ventilator that includes measuring some important physiological variables such as respiratory rate, heart rate, and O2 saturation, which can be utilized in hospital and at home. The proposed system includes Arduino, Raspberry pi4, touch screen, and graphical user interface. This study showed a significant individual performance for measuring some important parameters such as flow rate, tidal volume, and minute ventilation. The accuracy of measuring the flow rate was 72%. The Cohen's kappa (CK) was estimated to be 0.61. The accuracy of calculated the tidal volume was estimated at 83% with 0.80 CK. The accuracy of measuring the O2 saturation was estimated at 99% with 0.99 CK. The advantages of the proposed design are cost-effective, safe, flexible, and easy to use. Also, this system is smart and can control its transactions, so it can be used at home without the need for professional help. The operating parameters can also be set by the user with a simple user interface.Copyright © 2022 by ASME.

Persistent exertional dyspnea post COVID-19: potential mechanisms

Background: Patients recovered from COVID-19 often present with reduced exercise capacity and persistent exertional breathlessness, yet the mechanisms are still poorly understood. Method(s): We aimed to test patients formerly hospitalized for COVID-19 pneumonia with normal chest computed tomography (CT) at 6-month follow up but with persistent exertional breathlessness. Spirometry, chest CT, incremental cycle exercise test with arterial line, resting echocardiography and ventilation/perfusion (V/Q) scan were performed. Result(s): Data represents one patient and 4 healthy controls (CTRL) used for comparison. Patient (age: 41 vs. average 41.5 years in CTRL) was never smoker with FEV1 of 86 %predicted, normal chest CT and normal resting echocardiogram. Patient reported significant activity-related dyspnea (baseline dyspnea index score: 7). During exercise, peak work rate, ventilation, and oxygen update were within normal. Yet, patient had greater dyspnea intensity, ventilatory requirements and ventilatory equivalent for CO during exercise, with 4% drop in O2 saturation, 2 figure. Patient and CTRL had similar tidal volume (VT), rest-to-peak change in dead space/VT, and O2 pulse. V/Q scan showed multiple perfusion defects. Conclusion(s): Preliminary data shows that reduced ventilatory efficiency during exercise, suggesting pulmonary vascular abnormalities, could possibly explain persistent breathlessness in patients recovered from COVID pneumonia.

CPET ventilatory characteristics of dysfunctional breathing in long COVID patients with persistent dyspnea

Background: Cardio-pulmonary exercise test (CPET) can differentiate causes of persistent dyspnea beyond cardiopulmonary limitation. Dysfunctional breathing (DB) has been increasingly identified in long COVID in two main forms, hyperventilation [HV] or periodic deep sighing [PDS]. Aims and objectives: We aimed to contrast the CPET ventilatory parameters in post COVID patients without cardiopulmonary limitations. Four groups were compared a) normal CPET, b) PDS, c) HV and d) mixed pattern (PDS & HV). Method(s): CPET patterns (N, HV, PDS and mixed) were determined in 76 SARS-CoV2 patients [Mean age 48.2 (SD15.0), women (n=49, 64%)]. We compared breath by breath ventilatory parameters using raw data and coefficients of variation focusing on breathing frequency, tidal volume, VE/VCO2 and ins- and expiratory time. Result(s): Normal CPET were found in 26 (30%), HV in 12 (16%), PDS in 25 (33%) and mixed in 16 (21%)., dyspnea level and timing of evaluation between COVID and CPET (mean 230 days) were similar between groups. See figure for ventilatory parameters at rest and exercise. Conclusion(s): In long COVID patients with normal lung function and normal oxygen consumption but persistent dyspnea, assessment of the variability of ventilation at rest and exercise using CPET can reliably identify DB and differentiate its main forms (PDS or HV), thus offering a physiological explanation for dyspnea and allowing targeted therapy.

Evaluation of covid-19 lung involvement effect on exercise capacity in the 3rd and 6th months

Objective: Since Covid-19 was detected in December 2019, it has become evident that it causes different clinical courses. However, the long-term effect of acute severity of disease on systems is still unclear, particularly on exercise capacity. The aim of this study is to evaluate the effect of covid-19 lung involvement on the patients' exercise capacity with cardiopulmonary exercise test (CPET) in the post-covid 3rd and 6th months. Material-Methods: This is a prospective observational study. Between March 2021 and october 2021 76 patients,39 of these with covid-19 lung involvement, who are directed our exercise test laboratory enrolled to the study. All patients underwent pulmonary function and diffusion tests, 6-minute walking test and cpet. Result(s): A total of 76 patients, 31 females and 45 males, were evaluated. While Covid-19 patients with lung involvement were older than without lung involvement (49+/-14 vs 33+/-10, respectively, p=0.0001), body mass index was high in without lung involvement (26+/-4 vs 28+/-4, respectively, p=0.02). D-dimer and fibrinojen were high in lung involvement group (351+/-59 vs 134+/-21, 323+/-75 vs 230+/-43, p=0.002, p=0.0001, respectively). In third and sixth monts there was no differrence peak oygen consumption (VO2) between the groups (p=0.08). Of note, the results of the CPET revealed that lung-involvement group had low ventilatory efficiency (low breathing reserve (BR), and high physiological dead space/tidal volume ratio, VD/VT) (p=0.002, p=0.009, respectively) Conclusion(s): Our study showed that the effect of covid-19 lung involvement to restrict exercise capacity continues at 6 months.

Design of Fuzzy Logic-Based ARDS Berlin Definition for Ventilator Adjustments to Ensure Lung Protection

The studies done on lung protective strategies in medical ventilators have shown that tidal volume of 6-ml/ kg predicted body weight protects the lungs of a patient during the invasive ventilation for acute respiratory distress syndrome (ARDS) patients in intensive care unit. Corona virus disease 2019 has increased the need for mechanical ventilation, which are operated manually, in changing the settings on the mechanical ventilators. In this study, fuzzy logic method is used to develop a computer-aided decision-making to improve on the accuracy of the reasoning done during the ventilator setting adjustment, by adding the fuzzy reasoning concept into the ARDS Berlin definition. The ARDS positive end-expiratory pressure (PEEP) values were used in building the fuzzy rules of the fuzzy algorithm. From the experimental results, the algorithm mimics the recommended ARDS PEEP values with respect to the values of fraction of inspired oxygen (FiO2);the algorithm as well increases the respiratory rate and tidal volume for potential of Hydrogen (pH) less than 7.2;maintains the respiratory rate and tidal volume for pH between 7.2 and 7.4;decreases the respiratory rate;and maintains the tidal volume for pH greater than 7.4. The developed fuzzy system can therefore be applied as a physician–ventilator interface to guide the clinician/physician during the ventilation, so as, to reduce the human errors and ensure lung protection. © 2023, The Author(s) under exclusive licence to Taiwan Fuzzy Systems Association.