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Background Altered respiratory mechanics due to increased extrapulmonary mechanical load may be the key to understanding the profound effect of continuous positive airway pressure (CPAP) therapy in obesity hypoventilation syndrome (OHS). Methods We performed a cross-sectional study to assess intra-breath mechanical changes in an OHS population. 10 Hz intra-breath oscillometry and forced spirometry values were measured in the sitting and supine positions, followed by a supine oscillometry at different CPAP levels (none-5-10-15-20 cmH2O). We plotted intra-breath resistance (Rrs) and reactance (Xrs) values against flow and volume to analyse tidal changes in a more detailed manner.Results Thirty-five patients completed the study. Intra-breath reactance variables differed by body position (end-expiratory reactance: -1.85 (±1.89) hPa·s·L-1 vs -4.17 (±2.22) hPa·s·L-1, and by difference between end-expiratory and end-inspiratory reactance: -1.27 (±1.68) hPa·s·L-1 vs -3.56 (±2.02) hPa·s·L-1, sitting vs supine respectively, pXrs against tidal volume and flow, suggesting tEFL. Augmented CPAP levels were associated with improved Xrs values and reduced loop areas, suggesting diminished tEFL (pRrs values. No correlation was found between forced spirometry values and intra-breath oscillometry variables. We also did not detect correlation between intra-breath oscillometry variables and body mass index (BMI), OHS staging or age.Conclusion tEFL is frequently present in patients with OHS during quiet breathing, worsening in the supine position. CPAP appears to counteract this effect, suggesting that tEFL is an important factor in the pathomechanism of respiratory impairment and a possible target for optimizing therapy. Trial Registration This study was approved by and registered at the ethics committee of Semmelweis University (SE TUKEB 239/2018)

Összefoglaló. Számos közlemény született arról, hogy a COVID–19-pneumoniás betegek jelentős hányadában az artériás parciális oxigéntenzió kifejezetten alacsony, mégsem jellemző a dyspnoe, és a pulzusoximetria sem mutat – a csökkent oxigéntenzióval arányos – súlyos hypoxaemiát. A jelenséget „happy hypoxaemia” néven említik. Ugyanakkor a légszomjról nem panaszkodó, de súlyos alveolocapillaris O2-felvételi zavarban szenvedő COVID–19-pneumoniás betegek a legkisebb fizikai megterhelést sem tűrik, és állapotuk gyorsan kritikussá válhat, tehát a hypoxaemia mértékének időben való felismerése kulcskérdés. A jelen közleményben egy ilyen eset rövid ismertetése után összefoglaljuk a súlyos, de tünetmentes hypoxaemia hátterében meghúzódó élettani okokat. Ezek között szerepel a hypocapnia (respiratoricus alkalosis) is, mely alacsony oxigéntenzió mellett is a hemoglobin viszonylag megtartott oxigénszaturációját eredményezi. Ezért a mindennapi COVID–19-ellátásban a megismételt artériásvérgáz-meghatározások jelentősége nem hangsúlyozható eléggé. Orv Hetil. 2021; 162(10): 362–365. Summary. Many COVID-19 patients have very low arterial partial oxigen tension while severe dyspnoe does not develop. Pulse oxymetry indicates only moderate reduction of arterial O2 saturation in these patients. The phenomenon is named “happy hypoxaemia”. Lack of (severe) dyspnoe and only moderately decreased O2 saturation in severely impaired alveolo-capillary O2 uptake may partially be explained by an increased oxygen affinity of hemoglobin in the presence of low arterial partial pressure of CO2. The latter results from increased alveolar ventilation, while low partial pressure of O2 in COVID-19 patients reflects right-to-left shunting of pulmonary blood flow and ventilation-perfusion mismatch of the diseased lungs. While such patients may have mild complaints as related to the real impairment of alveolo-capillary oxygen exchange, severe hypoxaemia is a negative prognostic factor of outcome in this state where severe clinical deterioration may rapidly appear. The latter circumstance together with the unusual relationship of O2 partial pressure and O2 saturation of hemoglobin in COVID-19 emphasize the importance of repeated complete arterial blood gas analyses in these patients. Orv Hetil. 2021; 162(10): 362–365.

Background Home mechanical ventilation is an established treatment for chronic respiratory failure resulting in improved survival and quality of life. Technological advancement, evolving health care reimbursement systems and newly implemented national guidelines result in increased utilization worldwide. Prevalence shows great geographical variations and data on East-Central European practice has been scarce to date. The aim of the current study was to evaluate prevalence and characteristics of home mechanical ventilation in Hungary. Methods We conducted a nationwide study using an online survey focusing on patients receiving ventilatory support at home. The survey focused on characterization of the site (affiliation, type), experience with home mechanical ventilation, number of patients treated, indication for home mechanical ventilation (disease type), description of home mechanical ventilation (invasive/noninvasive, ventilation hours, duration of ventilation) and description of the care provided (type of follow up visits, hospitalization need, reimbursement). Results Our survey uncovered a total of 384 patients amounting to a prevalence of 3.9/100,000 in Hungary. 10.4% of patients received invasive, while 89.6% received noninvasive ventilation. The most frequent diagnosis was central hypopnea syndromes (60%), while pulmonary (20%), neuromuscular (11%) and chest wall disorders (7%) were less frequent indications. Daily ventilation need was less than 8 h in 74.2%, between 8 and 16 h in 15.4% and more than 16 h in 10.4% of patients reported. When comparing sites with a limited ( 50 patients) case number, we found the former had significantly higher ratio of neuromuscular conditions, were more likely to ventilate invasively, with more than 16 h/day ventilation need and were more likely to provide home visits and readmit patients (p

Abstract: Introduction: The use of noninvasive ventilation has increased worldwide. Its mortality reducing benefit has been shown in several different conditions compared to invasive ventilation. Common counterarguments against the technique are its increased technical and caregiver requirements and increased mortality associated with treatment failure. Aim: The aim of our work was to describe our experiences with noninvasive ventilation in the intensive care unit. Method: We reviewed patient data from the Respiratory Intensive Care unit of Semmelweis University operated from 2014 to 2016. Statistical analysis was performed by Mann–Whitney U test and Z-test; odds ratio was calculated with χ-square test. Results: Out of the 301 patients analyzed, 147 received noninvasive ventilation. Noninvasive failure rate was 24.5%. The highest failure rate was associated with immunodeficiency associated pneumonia, interstitial lung disease and pneumonia (71.4%, 33.3% and 31.6%), while noninvasive ventilation was the most successful in cardiogenic pulmonary edema and hypercapnic respiratory failure (0 and 16.7% failure rate). Treatment failure was associated with significantly higher mortality (33.3%) compared to patients initially ventilated invasively (24.5%) and patients successfully treated with noninvasive ventilation (3.6%), resulting in a 2.65-fold mortality increase in invasively ventilated patients (OR = 2.65, 95% CI = 1.305–5.374, p = 0.009), and a 13.33-fold mortality increase in noninvasive failure patients (OR = 13.33; 95% CI 3.278–54.238; p

Background It has been shown that home mechanical ventilation improves quality of life, but it has not been widely studied which particular patient groups benefit the most from starting this type of therapy. The purpose of this prospective observational study was to evaluate quality of life change patterns 6 months after initiation of home mechanical ventilation in patients suffering from chronic respiratory failure using patient reported outcomes. Methods We enrolled 74 chronic respiratory failure patients starting invasive or noninvasive home mechanical ventilation through the Semmelweis University Home Mechanical Ventilation Program. Quality of life was evaluated at baseline and at 6 months after initiation of home mechanical ventilation using the Severe Respiratory Insufficiency Questionnaire. Results Overall quality of life showed 10.5% improvement 6 months after initiation of home mechanical ventilation (p p = 0.015), Sleep and attendant symptoms (19.3%, p p p = 0.660). Severely impaired patients showed the greatest improvement (CC = -0.328, p p = 0.025), with chronic obstructive pulmonary disease and obesity hypoventilation syndrome patients showing the greatest improvement, while amyotrophic lateral sclerosis patients showed no improvement in quality of life. We found that patients who were started on long term ventilation in an acute setting, required oxygen supplementation and had low baseline quality of life, showed the most improvement during the six-month study period. Conclusions Our study highlights the profound effect of home mechanical ventilation on quality of life in chronic respiratory failure patients that is indifferent of ventilation interface but is dependent on initial diagnosis and some baseline characteristics, like acute initiation, oxygen supplementation need and baseline quality of life. Trial registration This study was approved by and registered at the ethics committee of Semmelweis University (SE TUKEB 251/2017; 20th of December, 2017).

Background Home mechanical ventilation is a reliable treatment for patients suffering from chronic respiratory failure, improving survival and quality of life. Prevalence has been increasing worldwide as a result of evolving technical possibilities, telemedicine and improving national guidelines. Projects to establish a national guideline and registry for patients treated with home mechanical ventilation are currently under way in Hungary and our aim was to validate a quality of life questionnaire suited for evaluation and follow up in this specific patient group. The Severe Respiratory Insufficiency Questionnaire (SRI) is a quality of life tool designed to evaluate patients receiving home mechanical ventilation and has been validated both in patient groups receiving invasive and noninvasive ventilation. Methods The Hungarian version of the SRI was created using the translation-backtranslation method, which was then tested for validity, viability and reliability in a cohort involving patients from three centers, receiving long-term home mechanical ventilation for chronic respiratory failure through an invasive or noninvasive interface. Patient data was collected (demographic data, lung function test, arterial blood gas, ventilation settings) and quality of life was measured with the previously validated SF-36 and newly created Hungarian SRI Questionnaires at two time points. Results One hundred four patients receiving home mechanical ventilation were enrolled. The time to complete the SRI Questionnaire was 8.6 (±3.1) minutes, 69.2% questionnaires were self-administered. Exploratory factor analysis explained 73.8% of the variance of the questionnaire, but resulted in 13 scales. We found correlations between the SRI subscale scores to corresponding scales of the previously validated general quality of life survey SF-36. The Cronbach alpha coefficient was 0.928 for the Summary Scale of the SRI Questionnaire, proving high internal consistency. Reproducibility was high for most scales, resulting in a high overall correlation for the summary score (0.877, p Conclusions The Hungarian version of the SRI Questionnaire is a viable, valid, reliable and reproduceable quality of life tool applicable for patients treated with home mechanical ventilation.

Tracking of the within-breath changes of respiratory mechanics using the forced oscillation technique may provide outcomes that characterise the dynamic behaviour of the airways during normal breathing.We measured respiratory resistance (Rrs) and reactance (Xrs) at 8 Hz in 55 chronic obstructive pulmonary disease (COPD) patients and 20 healthy controls, and evaluatedRrsandXrsas functions of gas flow (V′) and volume (V) during normal breathing cycles. In 12 COPD patients, additional measurements were made at continuous positive airway pressure (CPAP) levels of 4, 8, 14 and 20 hPa.TheRrsandXrsversus V′ andVrelationships displayed a variety of loop patterns, allowing characterisation of physiological and pathological processes. The main outcomes emerging from the within-breath analysis were theXrsversus Vloop area (AXV) quantifying expiratory flow limitation, and the tidal change inXrsduring inspiration (ΔXI) reflecting alteration in lung inhomogeneity in COPD. With increasing CPAP, AXV and ΔXIapproached the normal ranges, although with a large variability between individuals, whereas meanRrsremained unchanged.Within-breath tracking ofRrsandXrsallows an improved assessment of expiratory flow limitation and functional inhomogeneity in COPD; thereby it may help identify the physiological phenotypes of COPD and determine the optimal level of respiratory support.

Introduction: The 2009 pandemic 2009 H1N1 (pH1N1) influenza A virus shows a markedly different disease pattern than seasonal strains, causing critical illness in relatively young, female, pregnant individuals as well as in comorbid patients. Materials and methods: The Department of Anesthesiology and Intensive Therapy of Semmelweis University served as a regional influenza center for the adult critically ill during the winter of pH1N1 outbreak. We analyzed data collected from 26 suspected pH1N1 critically ill patients treated in our unit during this period. Results: Sixteen cases were confirmed as pH1N1 infection with RT-PCR, while the other 10 patients with influenza like illness showed tendency to a different age and comorbidity, as well as outcome characteristics, suggesting a different pathogenesis. Confirmed pH1N1 patients showed a mean age of 50.5 years (median: 44; range: 20–85), with female predominancy (69%). Comorbidity was present in 69% of cases (chronic heart conditions, chronic pulmonary disease, previous history of malignancy present in 31; 25 and 19%, respectively). Twenty-five percent of the patients were pregnant women. Nineteen percent of the cases received previous pH1N1 vaccination. But two patients were later readmitted for worsening chronic conditions that led to death, which resulted in a total mortality rate of 31%. Mean APACHE II and SOFA scores on admittance were 12.2 and 5.3, respectively. Average length of treatment was 11.5 days (median: 6.5; range 2–50 days). All patients received ventilatory assistance, 69% of patients received invasive, while 31% of patients received non-invasive ventilatory assistance. The average number of days of invasive ventilation was 10.5 days (median: 5.5; range: 2–45). Forty-five percent of ventilated patients required rescue ARDS therapy. Complications included hemodynamic instability (56%); acute renal failure (13%) and pneumothorax (13%). Superinfection with other microbes were observed in 56% of the patients. Conclusions: In our study, pH1N1 infected critically ill patients had a wide age range, but were more commonly female, pregnant, or had a previously described underlying disease. Mortality, length of treatment, need for invasive mechanical ventilation, length of mechanical ventilation, major complication rates were similar to those previously described. A previously not reported relatively high occurrence of pneumothorax was noted, which is possibly a long-term complication of severe viral pneumonitis.

Low-frequency forced oscillations have increasingly been employed to characterize airway and tissue mechanics separately in the normal respiratory system and animal models of lung disease; however, few data are available on the use of this method in chronic obstructive pulmonary disease (COPD). We studied 30 intubated and mechanically ventilated patients (COPD, n = 9; acute exacerbation of COPD, n = 21) during short apneic intervals at different levels of positive end-expiratory pressure (PEEP), with small-amplitude forced oscillations between 0.4 and 4.8 Hz. In 16 patients, measurements were made before and after inhalation of fenoterol hydrobromide plus ipratropium bromide (Berodual). Newtonian resistance and coefficients of tissue resistance (G) and elastance (H) were estimated from the respiratory system impedance (Zrs) data by model fitting. Apart from some extremely high Zrs data obtained primarily at relatively low PEEP levels, the model yielded a reasonable partitioning of the airway and tissue parameters, and the inclusion of further parameters did not improve the model performance. With increasing PEEP, Newtonian resistance and the ratio G/H decreased, reflecting the volume dependence of the airway caliber and the improved homogeneity of the lungs, respectively. Bronchodilation after the administration of Berodual was also associated with simultaneous decreases in G and H, indicating recruitment of lung units. In conclusion, the measurement of low-frequency Zrs can be accomplished in ventilated COPD patients during short apneic periods and offers valuable information on the mechanical status of the airways and tissues.