Changes in lung mechanics and ventilation-perfusion match: comparison of pulmonary air- and thromboembolism in rats.

BACKGROUND: Pulmonary air embolism (AE) and thromboembolism lead to severe ventilation-perfusion defects. The spatial distribution of pulmonary perfusion dysfunctions differs substantially in the two pulmonary embolism pathologies, and the effects on respiratory mechanics, gas exchange, and ventilation-perfusion match have not been compared within a study. Therefore, we compared changes in indices reflecting airway and respiratory tissue mechanics, gas exchange, and capnography when pulmonary embolism was induced by venous injection of air as a model of gas embolism or by clamping the main pulmonary artery to mimic severe thromboembolism. METHODS: Anesthetized and mechanically ventilated rats (n = 9) were measured under baseline conditions after inducing pulmonary AE by injecting 0.1 mL air into the femoral vein and after occluding the left pulmonary artery (LPAO). Changes in mechanical parameters were assessed by forced oscillations to measure airway resistance, lung tissue damping, and elastance. The arterial partial pressures of oxygen (PaO2) and carbon dioxide (PaCO2) were determined by blood gas analyses. Gas exchange indices were also assessed by measuring end-tidal CO2 concentration (ETCO2), shape factors, and dead space parameters by volumetric capnography. RESULTS: In the presence of a uniform decrease in ETCO2 in the two embolism models, marked elevations in the bronchial tone and compromised lung tissue mechanics were noted after LPAO, whereas AE did not affect lung mechanics. Conversely, only AE deteriorated PaO2, and PaCO2, while LPAO did not affect these outcomes. Neither AE nor LPAO caused changes in the anatomical or physiological dead space, while both embolism models resulted in elevated alveolar dead space indices incorporating intrapulmonary shunting. CONCLUSIONS: Our findings indicate that severe focal hypocapnia following LPAO triggers bronchoconstriction redirecting airflow to well-perfused lung areas, thereby maintaining normal oxygenation, and the CO2 elimination ability of the lungs. However, hypocapnia in diffuse pulmonary perfusion after AE may not reach the threshold level to induce lung mechanical changes; thus, the compensatory mechanisms to match ventilation to perfusion are activated less effectively.

Venovenous extracorporeal membrane oxygenation for COVID-19 associated severe respiratory failure: Case series from a Hungarian tertiary centre.

INTRODUCTION: Venovenous extracorporeal membrane oxygenation (V-V ECMO) is recommended for the support of patients with severe COVID-19 associated severe respiratory failure (SRF). We report the characteristics and outcome of COVID-19 patients supported with V-V ECMO in a Hungarian centre. METHODS: We retrospectively collected data on all patients admitted with proven SARS CoV-2 infection who received V-V ECMO support between March 2021 and May 2022. RESULTS: Eighteen patients were placed on ECMO during this period, (5 women, age (mean ± SD) 44 ± 10 years, APACHE II score (median (interquartile range)) 12 (10-14.5)). Before ECMO support, they had been hospitalised for 6 (4-11) days. Fifteen patients received noninvasive ventilation for 4 (2-8) days, two patients had high flow nasal oxygen therapy, for one day each. They had already been intubated for 2.5 (1-6) days. Prone position was applied in 15 cases. On the day before ECMO initiation the Lung Injury Score was 3.25 (3-3.26), the PaO2/FiO2 ratio was 71 ± 19 mmHg. The duration of V-V ECMO support was 26 ± 20 days, and the longest run lasted 70 days. Patients were mechanically ventilated for 34 ± 23 days. The intensive care unit (ICU) and the hospital length of stay were 40 ± 28 days and 45 ± 31 days, respectively. Eleven patients were successfully weaned from ECMO. The ICU survival rate was 56%, the in-hospital survival was 50%. All patients who were discharged from hospital reported a good health-related quality of life Rankin score (0-2) at the 5-16 months follow-up. CONCLUSIONS: During the last three waves of the COVID-19 pandemic, we achieved a 56% ICU and a 50% hospital survival rate at our low volume centre.

Post-COVID changes in lung function 6 months after veno-venous extracorporeal membrane oxygenation: a prospective observational clinical trial.

Background: Severe coronavirus disease 2019 (COVID-19) may require veno-venous extracorporeal membrane oxygenation (V-V ECMO). While V-V ECMO is offered in severe lung injury to COVID-19, long-term respiratory follow-up in these patients is missing. Therefore, we aimed at providing comprehensive data on the long-term respiratory effects of COVID-19 requiring V-V ECMO support during the acute phase of infection. Methods: In prospective observational cohort study design, patients with severe COVID-19 receiving invasive mechanical ventilation and V-V ECMO (COVID group, n = 9) and healthy matched controls (n = 9) were evaluated 6 months after hospital discharge. Respiratory system resistance at 5 and 19 Hz (R5, R19), and the area under the reactance curve (AX5) was evaluated using oscillometry characterizing total and central airway resistances, and tissue elasticity, respectively. R5 and R19 difference (R5-R19) reflecting small airway function was also calculated. Forced expired volume in seconds (FEV1), forced expiratory vital capacity (FVC), functional residual capacity (FRC), carbon monoxide diffusion capacity (DLCO) and transfer coefficient (KCO) were measured. Results: The COVID group had a higher AX5 and R5-R19 than the healthy matched control group. However, there was no significant difference in terms of R5 or R19. The COVID group had a lower FEV1 and FVC on spirometry than the healthy matched control group. Further, the COVID group had a lower FRC on plethysmography than the healthy matched control group. Meanwhile, the COVID group had a lower DLCO than healthy matched control group. Nevertheless, its KCO was within the normal range. Conclusion: Severe acute COVID-19 requiring V-V ECMO persistently impairs small airway function and reduces respiratory tissue elasticity, primarily attributed to lung restriction. These findings also suggest that even severe pulmonary pathologies of acute COVID-19 can manifest in a moderate but still persistent lung function impairment 6 months after hospital discharge. Trial registration: NCT05812196.

Expiratory high-frequency percussive ventilation: a novel concept for improving gas exchange.

BACKGROUND: Although high-frequency percussive ventilation (HFPV) improves gas exchange, concerns remain about tissue overdistension caused by the oscillations and consequent lung damage. We compared a modified percussive ventilation modality created by superimposing high-frequency oscillations to the conventional ventilation waveform during expiration only (eHFPV) with conventional mechanical ventilation (CMV) and standard HFPV. METHODS: Hypoxia and hypercapnia were induced by decreasing the frequency of CMV in New Zealand White rabbits (n = 10). Following steady-state CMV periods, percussive modalities with oscillations randomly introduced to the entire breathing cycle (HFPV) or to the expiratory phase alone (eHFPV) with varying amplitudes (2 or 4 cmH2O) and frequencies were used (5 or 10 Hz). The arterial partial pressures of oxygen (PaO2) and carbon dioxide (PaCO2) were determined. Volumetric capnography was used to evaluate the ventilation dead space fraction, phase 2 slope, and minute elimination of CO2. Respiratory mechanics were characterized by forced oscillations. RESULTS: The use of eHFPV with 5 Hz superimposed oscillation frequency and an amplitude of 4 cmH2O enhanced gas exchange similar to those observed after HFPV. These improvements in PaO2 (47.3 ± 5.5 vs. 58.6 ± 7.2 mmHg) and PaCO2 (54.7 ± 2.3 vs. 50.1 ± 2.9 mmHg) were associated with lower ventilation dead space and capnogram phase 2 slope, as well as enhanced minute CO2 elimination without altering respiratory mechanics. CONCLUSIONS: These findings demonstrated improved gas exchange using eHFPV as a novel mechanical ventilation modality that combines the benefits of conventional and small-amplitude high-frequency oscillatory ventilation, owing to improved longitudinal gas transport rather than increased lung surface area available for gas exchange.

Seasonal changes in proportion of cardiac surgeries associated with diabetes, smoking and elderly age.

BACKGROUND: Seasonal variations in the ambient temperature may affect the exacerbation of cardiovascular diseases. Our primary objective was to evaluate the seasonality of the monthly proportion of cardiac surgeries associated with diabetes, smoking and/or elderly age at a tertiary-care university hospital in East-Central Europe with a temperate climate zone. As a secondary objective, we also assessed whether additional factors affecting small blood vessels (smoking, aging, obesity) modulate the seasonal variability of diabetes. METHODS: Medical records were analyzed for 9838 consecutive adult patients who underwent cardiac surgery in 2007-2018. Individual seasonal variations of diabetes, smoking, and elderly patients were analyzed monthly, along with the potential risk factors for cardiovascular complication. We also characterized whether pairwise coexistence of diabetes, smoking, and elderly age augments or blunts the seasonal variations. RESULTS: Seasonal variations in the monthly proportion of cardiac surgeries associated with diabetes, smoking and/or elderly age were observed. The proportion of cardiac surgeries of non-elderly and smoking patients with diabetes peaked in winter (amplitude of change as [peak-nadir]/nadir: 19.2%, p<0.02), which was associated with increases in systolic (6.1%, p<0.001) and diastolic blood pressures (4.4%, p<0.05) and serum triglyceride levels (27.1%, p<0.005). However, heart surgery in elderly patients without diabetes and smoking was most frequently required in summer (52.1%, p<0.001). Concomitant occurrence of diabetes and smoking had an additive effect on the requirement for cardiac surgery (107%, p<0.001), while the simultaneous presence of older age and diabetes or smoking eliminated seasonal variations. CONCLUSIONS: Scheduling regular cardiovascular control in accordance with periodicities in diabetes, elderly, and smoking patients more than once a year may improve patient health and social consequences. TRIAL REGISTRATION: NCT03967639.

Exaggerated Ventilator-Induced Lung Injury in an Animal Model of Type 2 Diabetes Mellitus: A Randomized Experimental Study.

Although ventilator-induced lung injury (VILI) often develops after prolonged mechanical ventilation in normal lungs, pulmonary disorders may aggravate the development of adverse symptoms. VILI exaggeration can be anticipated in type 2 diabetes mellitus (T2DM) due to its adverse pulmonary consequences. Therefore, we determined whether T2DM modulates VILI and evaluated how T2DM therapy affects adverse pulmonary changes. Rats were randomly assigned into the untreated T2DM group receiving low-dose streptozotocin with high-fat diet (T2DM, n = 8), T2DM group supplemented with metformin therapy (MET, n = 8), and control group (CTRL, n = 8). In each animal, VILI was induced by mechanical ventilation for 4 h with high tidal volume (23 ml/kg) and low positive end-expiratory pressure (0 cmH2O). Arterial and venous blood samples were analyzed to measure the arterial partial pressure of oxygen (PaO2), oxygen saturation (SaO2), and the intrapulmonary shunt fraction (Qs/Qt). Airway and respiratory tissue mechanics were evaluated by forced oscillations. Lung histology samples were analyzed to determine injury level. Significant worsening of VILI, in terms of PaO2, SaO2, and Qs/Qt, was observed in the T2DM group, without differences in the respiratory mechanics. These functional changes were also reflected in lung injury score. The MET group showed no difference compared with the CTRL group. Gas exchange impairment without significant mechanical changes suggests that untreated diabetes exaggerates VILI by augmenting the damage of the alveolar-capillary barrier. Controlled hyperglycemia with metformin may reduce the manifestations of respiratory defects during prolonged mechanical ventilation.

Lung and chest wall mechanical properties in metformin-treated and untreated models of type 2 diabetes.

The adverse respiratory consequences of type 2 diabetes mellitus (T2DM) may reflect compromised lung function and/or alterations of the chest wall because of skeletal muscle stiffening. We assessed the separate contributions of these compartments to respiratory complications in diabetes and explored the effects of metformin on respiratory abnormalities. Experiments were performed in untreated rats (control, n = 7), high-fat diet-fed rats receiving streptozotocin (T2DM, n = 7), and metformin-treated diabetic rats (MET, n = 6). Newtonian resistance, tissue damping, and elastance were separately assessed for lung and chest wall components by measuring the esophageal pressure during forced oscillations at low (0 cmH2O), medium (3 cmH2O), and high positive end-expiratory pressure (PEEP) (6 cmH2O). Tissue hysteresivity was calculated as damping/elastance. Blood gas parameters were used to assess gas exchange, and lung histology was performed to characterize collagen expression. T2DM at low PEEP compromised airway and lung tissue mechanics in association with gas-exchange defects and collagen overexpression. Abnormal chest wall mechanics in T2DM was indicated only by decreased tissue hysteresivity. No difference in lung or chest wall mechanics, gas exchange, or lung histology was observed between the MET and control groups. These findings suggest the primary involvement of the pulmonary system in the respiratory consequences of T2DM, with chest wall properties only disturbed by a shift toward the dominance of elastic forces at low PEEP. The adequacy of metformin to treat the adverse respiratory consequences of diabetes was also revealed, in addition to its well-established beneficial effects on other organs.NEW & NOTEWORTHY The present study examined the contributions of the lungs and chest wall to respiratory complications in a rat model of diabetes and clarified the effects of metformin on these changes. At low positive end-expiratory pressure, type 2 diabetes was linked to dysfunctional airway and lung tissue mechanics in relation with gas-exchange defects and collagen overexpression, whereas decreased tissue hysteresivity was manifested in the chest wall abnormalities. Metformin treated all adverse respiratory consequences of diabetes.

Respiratory consequences of obesity and diabetes / Az elhízás és a cukorbetegség légzorendszeri következményei

Összefoglaló. Bevezetés: A cukorbetegségben no a simaizmok tónusa, és megváltozik az elasztin és a kollagén szerkezete. Mivel a tüdoszövetben ezek a strukturális elemek meghatározóak, a cukorbetegség várhatóan módosítja a légutak és a tüdoszövet mechanikai és funkcionális viselkedését. Célkituzés: Vizsgálatunk során diabetesben szenvedo, elhízott és nem elhízott betegeink körében tanulmányoztuk a légzésmechanikai elváltozásokat és a gázcserefunkciót. Módszer: Elektív szívsebészeti beavatkozásra kerülo, normál testalkatú betegeket diabetesben nem szenvedo (n = 80), illetve cukorbeteg (n = 35) csoportokra osztottuk. További két betegcsoportba elhízott és nem cukorbeteg (n = 47), valamint elhízott és diabetesben szenvedo (n = 33) betegek kerültek. A légzorendszer mechanikai tulajdonságait kényszerített oszcillációs technikával határoztuk meg, mellyel a légúti ellenállás (Raw), valamint a szöveti csillapítás (G) és rugalmasság (H) tényezoi jellemezhetok. Volumetriás kapnográfia segítségével a kapnogram 3. fázisának meredekségét és a légzési térfogat különbözo ventilációs/perfúziós illeszkedési zavaraiból adódó holttérfrakciókat határoztuk meg. Az intrapulmonalis shuntfrakciót és az oxigenizációs indexet (PaO2/FiO2) artériás és centrális vénás vérgázmintákból határoztuk meg. Eredmények: A megfelelo kontrollcsoportokhoz hasonlítva a cukorbetegség önmagában is növelte az Raw (7,4 ± 5 vs. 3,0 ± 1,7 H2Ocm.s/l), a G (11,3 ± 4,9 vs. 6,2 ± 2,4 H2Ocm/l) és a H (32,3 ± 12,0 vs. 25,1± 6,9 H2Ocm/l) értékét (p<0,001 mindegyik betegcsoportnál), de ez nem járt együtt a gázcserefunckció romlásával. Hasonló patológiás elváltozásokat észleltünk elhízás során a légzésmechanikában és az alveolaris heterogenitásban, amelyek azonban a gázcsere hatékonyságát is rontották. Következtetés: Cukorbetegségben a légzésmechanika romlását a fokozott hypoxiás pulmonalis vasoconstrictio ellensúlyozni képes, ezzel kivédve az intrapulmonalis shunt növekedését és az oxigenizációs képesség romlását. Orv Hetil. 2022; 163(2): 63-73. INTRODUCTION: While sustained hyperglicemia affects the smooth muscle tone and the elastin-collagen network, the effect of diabetes mellitus on the function and structure of the airways and the lung parenchyma has not been characterized, and the confounding influence of obesity has not been elucidated. OBJECTIVE: To reveal the separate and additive roles of diabetes mellitus and obesity on the respiratory function. METHOD: Non-obese mechanically ventilated patients were categorized as control non-diabetic (n = 80) and diabetic (n = 35) groups. Obese patients with (n = 33) or without (n = 47) associated diabetes were also enrolled. Forced oscillation technique was applied to measure airway resistance (Raw), tissue damping (G), and tissue elastance (H). Capnography was utilized to determine phase 3 slopes and ventilation dead space parameters. Arterial and central venous blood samples were analyzed to assess intrapulmonary shunt fraction (Qs/Qt) and the lung oxygenation index (PaO2/FiO2). RESULTS: Diabetes without obesity increased the Raw (7.4 ± 5 cmH2O.s/l vs. 3.0 ± 1.7 cmH2O.s/l), G (11.3 ± 4.9 cmH2O/l vs. 6.2 ± 2.4 cmH2O/l), and H (32.3 ± 12.0 cmH2O/l vs. 25.1 ± 6.9 cmH2O/l, (p<0.001 for all), compared with the corresponding control groups. Capnographic phase 3 slope was increased in diabetes without significant changes in PaO2/FiO2 or Qs/Qt. While similar detrimental changes in respiratory mechanics and alveolar heterogeneity were observed in obese patients without diabetes, these alterations also compromised gas exchange. CONCLUSION: The intrinsic mechanical abnormalities in the airways and lung tissue induced by diabetes are counterbalanced by hypoxic pulmonary vasoconstriction, thereby maintaining intrapulmonary shunt fraction and oxygenation ability of the lungs. Orv Hetil. 2022; 163(2): 63-73.

Dopamine Reverses Lung Function Deterioration After Cardiopulmonary Bypass Without Affecting Gas Exchange.

OBJECTIVE: To investigate the effects of dopamine on the adverse pulmonary changes after cardiopulmonary bypass. DESIGN: A prospective, nonrandomized clinical investigation. SETTING: A university hospital. PARTICIPANTS: One hundred fifty-seven patients who underwent elective cardiac surgery that required cardiopulmonary bypass. INTERVENTIONS: Fifty-two patients were administered intravenous infusion of dopamine (3 µg/kg/min) for five minutes after weaning from cardiopulmonary bypass; no intervention was applied in the other 105 patients. MEASUREMENTS AND MAIN RESULTS: Measurements were performed under general anesthesia and mechanical ventilation before cardiopulmonary bypass, after cardiopulmonary bypass, and after the intervention. In each protocol stage, forced oscillatory lung impedance was measured to assess airway and tissue mechanical changes. Mainstream capnography was performed to assess ventilation- and/or perfusion-matching by calculating the normalized phase-3 slopes of the time and volumetric capnograms and the physiologic deadspace. Arterial and central venous blood samples were analyzed to characterize lung oxygenation and intrapulmonary shunt. After cardiopulmonary bypass, dopamineinduced marked improvements in airway resistance and tissue damping, with relatively small decreases in lung tissue elastance. These changes were associated with decreases in the normalized phase-3 slopes of the time and volumetric capnograms. The inotrope had no effect on physiologic deadspace, intrapulmonary shunt, or lung oxygenation. CONCLUSION: Dopamine reversed the complex detrimental lung mechanical changes induced by cardiopulmonary bypass and alleviated ventilation heterogeneities without affecting the physiologic deadspace or intrapulmonary shunt. Therefore, dopamine has a potential benefit on the gas exchange abnormalities after weaning from cardiopulmonary bypass.

Gestational hemostasis: a natural model for hemostasis resuscitation of major periprocedural blood loss : "Look deep into nature, and then you will understand everything better." Albert Einstein.

Early goal-directed treatment is an evidence-based approach to guide hemostatic therapy during major periprocedural bleeding. If viscoelastic coagulation tests are not available, an algorithm, termed the pyramid of hemostatic interventions, can help manage severe bleeding. Pregnant women accumulate huge reserves of prothrombotic and antifibrinolytic hemostatic elements to avoid peripartum blood loss. We provide comparison of therapeutic hemostatic approaches and natural gestational process and identified remarkable analogy between early goal-directed management of bleeding and hemostatic adaptation of pregnant woman. Therefore, gestational hemostasis serves as a natural model for goal-directed hemostasis resuscitation and can foster understanding of hemostatic management of periprocedural bleeding.

Comparison of the Previous and Current Trauma-Related Shock Classifications: A Retrospective Cohort Study from a Level I Trauma Center.

PURPOSE: The aim was to examine the predictive value of the hypovolemic shock classification currently accepted by the Advanced Trauma Life Support (ATLS) program over the previous one, which used only vital signs (VS) for patient allocation. The primary outcome was 30-day mortality; as secondary outcome, heart rate (HR), systolic blood pressure (SBP), Glasgow Coma Scale (GCS) and base deficit (BD) data were compared and investigated in terms of mortality prediction. METHODS: Retrospective analysis at a level I trauma center between 2014 and 2019. Adult patients treated by trauma teams were allocated into severity classes (I-IV) based on the criteria of the current and previous ATLS classifications, respectively. The prognostic values for the classifications were determined with Fisher's exact test and χ2 test for independence, and compared with the 2-proportion Z test. The individual variables were analyzed with receiver-operating characteristic (ROC) analyses. RESULTS: A total of 156 patients met the inclusion criteria. Mortality was effectively predicted by both classifications, and there was no statistically significant difference between the predictive performances. According to ROC analyses, GCS, BD and SBP had significant prognostic values while HR change was ineffective in this regard. CONCLUSIONS: The currently used ATLS shock classification does not appear to be superior to the VS-based previous classification. GCS, BD and SBP are useful parameters to predict the prognosis. Changes in HR do not reflect the clinical course accurately; thus, further studies will be needed to determine the value of this parameter in trauma-associated hypovolemic-hemorrhagic shock conditions.

Extracorporeal membrane oxygenation in intensive care unit / Extracorporalis membránoxigenizáció intenzív osztályon.

Összefoglaló. Az extracorporalis membránoxigenizációt egyre gyakrabban alkalmazzák világszerte refrakter légzési és/vagy keringési elégtelenség kezelésében. Intézetünkben 2015-ben kezdtük meg a program elokészítését és felépítését. Célunk az extracorporalis membránoxigenizációs kezelés élettani alapjainak rövid ismertetése, különös tekintettel a venovenosus konfigurációra, és az eddig kezelt eseteink eredményeinek összefoglalása. Az irodalom szisztematikus áttekintése és a kezelt esetek adatainak retrospektív értékelése voltak a módszereink. 2016 óta összesen 14 beteg esetében használtunk extracorporalis membránoxigenizációt (8 férfi, 6 no, életkor 51 ± 15 év, APACHE II. score 24 ± 7). Az indikáció 9 esetben súlyos refrakter hypoxaemiás légzési elégtelenség, 1 esetben tracheooesophagealis fistula és légzési elégtelenség, 1 esetben mutét alatti támogatás tervezett trachearekonstrukció során és 3 beteg esetében refrakter cardiogen shock volt. Az extracorporalis membránoxigenizáció 11 betegben a légzés, 3 betegben a keringés támogatását szolgálta, 13 venovenosus, 1 venoarteriosus konfigurációban. Az extracorporalis támogatás ideje légzéstámogatás esetében 14 ± 6 nap, a cardialis támogatások esetében 5 ± 4 nap volt. Az intenzív osztályos ápolási ido 27 ± 13, illetve 21 ± 17 nap volt a két betegcsoportban. 9 beteget jó funkcionális állapotban bocsátottunk el, 5 beteg halt meg osztályunkon, további 3 késobb a kórházi bennfekvés során. Az extracorporalis membránoxigenizációs program regionális centrumokban Magyarországon is megvalósítható. A nemzetközi ajánlások, oktatási módszerek alkalmazásával a nemzetközi irodalomban közölt túlélési eredményekhez hasonló eredmények érhetok el hazánkban is. Orv Hetil. 2021; 162(11): 425-431. Summary. Extracorporeal membrane oxygenisation is commonly used worldwide for refractory respiratory and circulatory failure. We started to organise the introduction of this therapeutic modality in 2015. Our aim is to give a short review about extracorporeal life support, especially veno-venous extracorporeal membrane oxygenation, and to present our first results. We provide a systematic review of the currently available literature and a summary of our first treatments. As of 2016, we supported 14 patients with extracorporeal membrane oxygenisation (8 men, age 51 ± 15 years, APACHE II score 24 ± 7). The indications were refractory hypoxaemic respiratory failure in 9, tracheo-oesophageal fistula and respiratory failure in 1, support during surgery for planned tracheal reconstruction in 1, and refractory cardiogenic shock in 3 patients. We provided respiratory support in 11, circulatory support in 3 cases, with 13 veno-venous and 1 veno-arterial configuration. The support lasted for 14 ± 6 days in respiratory, and for 5 ± 4 days in cardiac cases. Intensive care length of stay was 27 ± 13 and 21 ± 17 days in the two patient groups. We discharged 9 patients in good functional state, 5 patients died during intensive care and further 3 later, during the hospital stay. Our results show that the implementation of an extracoporeal membrane oxygenation program is feasible in Hungarian tertiary centers. In line with international recommendations and adapting international training courses, the survival is very similar to that reported in the literature. Orv Hetil. 2021; 162(11): 425-431.

Use of capnography to verify emergency ventilator sharing in the COVID-19 era.

Exacerbation of COVID-19 pandemic may lead to acute shortage of ventilators, which may require shared use of ventilator as a lifesaving concept. Two model lungs were ventilated with one ventilator to i) test the adequacy of individual tidal volumes via capnography, ii) assess cross-breathing between lungs, and iii) offer a simulation-based algorithm for ensuring equal tidal volumes. Ventilation asymmetry was induced by placing rubber band around one model lung, and the uneven distribution of tidal volumes (VT) was counterbalanced by elevating airflow resistance (HR) contralaterally. VT, end-tidal CO2 concentration (ETCO2), and peak inspiratory pressure (Ppi) were measured. Unilateral LC reduced VT and elevated ETCO2 on the affected side. Under HR, VT and ETCO2 were re-equilibrated. In conclusion, capnography serves as simple, bedside method for controlling the adequacy of split ventilation in each patient. No collateral gas flow was observed between the two lungs with different time constants. Ventilator sharing may play a role in emergency situations.

Obesity and diabetes: similar respiratory mechanical but different gas exchange defects.

Diabetes mellitus increases smooth muscle tone and causes tissue remodeling, affecting elastin and collagen. Although the lung is dominated by these elements, diabetes is expected to modify the airway function and respiratory tissue mechanics. Therefore, we characterized the respiratory function in patients with diabetes with and without associated obesity. Mechanically ventilated patients with normal body shapes were divided into the control nondiabetic (n = 73) and diabetic (n = 31) groups. The other two groups included obese patients without diabetes (n = 43) or with diabetes (n = 30). The mechanical properties of the respiratory system were determined by forced oscillation technique. Airway resistance (Raw), tissue damping (G), and tissue elastance (H) were assessed by forced oscillation. Capnography was applied to determine phase 3 slopes and dead space indices. The intrapulmonary shunt fraction (Qs/Qt) and the lung oxygenation index (PaO2/FIO2) were estimated from arterial and central venous blood samples. Compared with the corresponding control groups, diabetes alone increased the Raw (7.6 ± 6 cmH2O.s/l vs. 3.1 ± 1.9 cmH2O.s/l), G (11.7 ± 5.5 cmH2O/l vs. 6.5 ± 2.8 cmH2O/l), and H (31.5 ± 11.8 cmH2O/l vs. 24.2 ± 7.2 cmH2O/l (P < 0.001 for all). Diabetes increased the capnographic phase 3 slope, whereas PaO2/FIO2 or Qs/Qt was not affected. Obesity alone caused similar detrimental changes in respiratory mechanics and alveolar heterogeneity, but these alterations also compromised gas exchange. We conclude that diabetes-induced intrinsic mechanical abnormalities are counterbalanced by hypoxic pulmonary vasoconstriction, which maintained intrapulmonary shunt fraction and oxygenation ability of the lungs.

Perioperative Patient Blood Management: common risk, common tasks, common responsibility / Perioperatív vérfelhasználás: közös kockázat, közös feladatok, közös felelosség.

Human red blood cell concentrate and platelet suspension are unstable preparations, therefore, they are not part of the international pharmaceutical market for biological and economic reasons. Consequently, they cannot be replaced by external sources. Human allogeneic erythrocyte and platelet preparations should therefore be considered as part of the common national wealth. The amount of transfused red blood cell concentrate has been declining in countries with advanced health systems in recent years. The changes were initially driven by the spread of the concept and practice of liberal and restrictive transfusion triggers. A complex, thoughtful system of perioperative blood utilization, the Patient Blood Management has later emerged, and a paradigm shift in the delivery of life-threatening perioperative bleeding has developed. At the same time, clinical practitioners are facing a new challenge of reducing willingness to donate blood worldwide. The rationalization of the use of human red blood cell concentrate and platelet suspension is essential in Hungary. As a health care measure, the currently rigidly earmarked financial resources available for allogeneic preparations and stable factor concentrates for the treatment of life-threatening haemorrhages need to be changed to be interoperable. The perioperative blood use could additionally be reduced by the widespread dissemination of the Patient Blood Management requiring complex coordinated educational interdisciplinary and logistical work. Orv Hetil. 2020; 161(37): 1545-1553.

Principles of the perioperative Patient Blood Management / A perioperatív vérgazdálkodási program alapelvei.

The perioperative Patient Blood Management (in Hungary National Blood Donation and Blood Saving Program) is an individualized clinical practice based on a multidisciplinary consensus with a comprehensive and complex approach. It supports the rational and judicious utilization of blood products and abolishes irrational transfusion policy. Its practical implementation is based upon three pillars: 1. anemia management without transfusion, if possible; restrictive transfusion strategy; 2. minimization of blood loss; 3. enhancement of anemia tolerance. Early detection, clarification of etiology and appropriate treatment are the most important tools for the management of preoperative anemia before surgeries with a high risk of bleeding. Minimization of blood loss can be achieved by identifying patients with congenital or acquired bleeding disorders, preparing them appropriately for surgery, discontinuing anticoagulants and antiplatelet drugs for a sufficient time in the preoperative phase of surgery and reversing their effects to comply with current guidelines. Minimal-invasive approaches are preferable. Intraoperatively, atraumatic technique and accurate topical haemostasis should be provided by surgeons. Autologous blood salvage techniques and controlled hypotension in lack of contraindications can also reduce the amount of blood loss. In cases of perioperative bleeding, protocols based on international guidelines but adapted to local circumstances must be used. Ideally, it should be managed by viscoelastic test-guided, goal-directed, individualized and factor concentrate-based algorithm. Perioperatively, an ideal oxygen demand/supply ratio must be ensured to avoid oxygen debt. Restoration and maintenance of homeostasis are essential for both the effectively functioning haemostatic system and the avoidance of oxygen deficit. Implementation of the Patient Blood Management improves patient safety, reduces the cost of medical care and facilitates the national blood product supply. Its successful introduction is our common interest. Orv Hetil. 2020; 161(37): 1554-1568.

Epidemiology of anemia / Az anaemiák epidemiológiája.

Worldwide, the prevalence of anemia is high, and iron deficiency anemia is the fifth most common disorder according to the study called "Global burden of disease". It can be attributed to a number of factors, complex pathomechanisms, and etiology is highly variable in terms of age, gender, and geographical distribution. The prevalence of anemia increases with age. Demographic change and the aging of the population are now faster than in previous decades, posing major challenges to societies and health systems. The mean prevalence of anemia in the elderly is 17%, but significantly higher among nursing-home (47%) and hospitalized elderly (40%). The cause is usually multifactorial and often, due to comorbidities, several mechanisms are involved at the same time. The prevalence of preoperative anemia was higher (35%) than the prevalence of anemia in the general population, and evidence showed an unfavorable effect on postoperative morbidity and mortality. Timely identification and correction is a multidisciplinary task and a shared responsibility for both Patient Blood Management program and improving the patients' life expectancy. Orv Hetil. 2020; 161(37): 1569-1573.

National Blood Donation and Blood Saving Program in Hungary. Further steps are required to improve patient safety. / A Nemzeti Véradó és Vérmento Program helyzete Magyarországon. További lépések szükségesek a betegbiztonság fokozásához.

INTRODUCTION AND AIM: In the last decade, guidelines and trainings promoted haemostasis point-of-care tests, availability and application of factor products, while they led to a decrease in blood product consumption. The aim of this study is to examine protocols, conditions in terms of facilities, equipment, personnel of anaesthesia-intensive care units (A-ICU) to improve healthcare services and patient safety. METHOD: In 2019, self-reported questionnaires were sent in e-mail to A-ICUs. Application of guidelines and local protocols, education, haemostasis diagnostic tools, availability of allogeneic transfusion products, stable factor and drug products for restoring haemostasis were evaluated. RESULTS: 49% of A-ICUs filled out 46 questionnaires. 91.3% applied guidelines, 43.5% had local protocols. The lack of haemostasis and Patient Blood Management (PBM) trainings was indicated by 6 and 17 A-ICUs, respectively. Applying MAITT guidelines decreased red blood cell concentrate (RBC), fresh frozen plasma (FFP) and thrombocyte consumption by 65.1%, 67.4% and 30.2%. The availability of laboratory and viscoelastic tests is limited except for blood count, INR, APTI, fibrinogen. Where viscoelastic tests were available, RBC 2.9, FFP 1.7, thrombocyte 2.5 times more physicians per A-ICU beds participated in haemostasis trainings. 32% of A-ICUs can provide the required amount of factor products in the case of massive bleeding. CONCLUSION: Haemostasis and PBM trainings improve the quality of healthcare services if necessary equipment, factor and haemostasis drug products are provided. In order to promote PBM programmes and to improve patient safety, rearrangement of service and financing structure is needed, which must be accompanied by consulting perioperative professionals, general practitioners, and other related experts. Orv Hetil. 2020; 161(37): 1606-1616.

Tracheostomy during novel corona virus pandemic. / Tracheotomia az új típusú koronavírus okozta járvány idején(A COVID-19-pandémia orvosszakmai kérdései).

Recently, 6 percent of COVID-19 patients required prolonged mechanical ventilation due to severe respiratory failure. Early tracheostomy prevents the risk of postintubation upper airway stenosis. In the pandemic, all surgical interventions that generate aerosol increase the risk of contamination of the medical staff, for which reason the "traditional" indications of tracheostomy have to be revised. Authors present their recommendations based on international experiences. Orv Hetil. 2020; 161(19): 767-770.