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.

Capnographic Parameters in Ventilated Patients: Correspondence with Airway and Lung Tissue Mechanics.

BACKGROUND: Although the mechanical status of the lungs affects the shape of the capnogram, the relations between the capnographic parameters and those reflecting the airway and lung tissue mechanics have not been established in mechanically ventilated patients. We, therefore, set out to characterize how the mechanical properties of the airways and lung tissues modify the indices obtained from the different phases of the time and volumetric capnograms and how the lung mechanical changes are reflected in the altered capnographic parameters after a cardiopulmonary bypass (CPB). METHODS: Anesthetized, mechanically ventilated patients (n = 101) undergoing heart surgery were studied in a prospective consecutive cross-sectional study under the open-chest condition before and 5 minutes after CPB. Forced oscillation technique was applied to measure airway resistance (Raw), tissue damping (G), and elastance (H). Time and volumetric capnography were performed to assess parameters reflecting the phase II (SII) and phase III slopes (SIII), their transition (D2min), the dead-space indices according to Fowler, Bohr, and Enghoff and the intrapulmonary shunt. RESULTS: Before CPB, SII and D2min exhibited the closest (P = 0.006) associations with H (0.65 and -0.57; P < 0.0001, respectively), whereas SIII correlated most strongly (P < 0.0001) with Raw (r = 0.63; P < 0.0001). CPB induced significant elevations in Raw and G and H (P < 0.0001). These adverse mechanical changes were reflected consistently in SII, SIII, and D2min, with weaker correlations with the dead-space indices (P < 0.0001). The intrapulmonary shunt expressed as the difference between the Enghoff and Bohr dead-space parameters was increased after CPB (95% ± 5% [SEM] vs 143% ± 6%; P < 0.001). CONCLUSIONS: In mechanically ventilated patients, the capnographic parameters from the early phase of expiration (SII and D2min) are linked to the pulmonary elastic recoil, whereas the effect of airway patency on SIII dominates over the lung tissue stiffness. However, severe deterioration in lung resistance or elastance affects both capnogram slopes.

Effects of respiratory mechanics on the capnogram phases: importance of dynamic compliance of the respiratory system.

INTRODUCTION: The slope of phase III of the capnogram (SIII) relates to progressive emptying of the alveoli, a ventilation/perfusion mismatch, and ventilation inhomogeneity. S(III) depends not only on the airway geometry, but also on the dynamic respiratory compliance (Crs); this latter effect has not been evaluated. Accordingly, we established the value of SIII for monitoring airway resistance during mechanical ventilation. METHODS: Sidestream capnography was performed during mechanical ventilation in patients undergoing elective cardiac surgery (n = 144). The airway resistance (Raw), total respiratory resistance and Crs displayed by the ventilator, the partial pressure of arterial oxygen (PaO2) and S(III) were measured in time domain (S(T-III)) and in a smaller cohort (n = 68) by volumetry (S(V-III)) with and without normalization to the average CO2 phase III concentration. Measurements were performed at positive end-expiratory pressure (PEEP) levels of 3, 6 and 9 cmH2O in patients with healthy lungs (Group HL), and in patients with respiratory symptoms involving low (Group LC), medium (Group MC) or high Crs (Group HC). RESULTS: S(T-III) and S(V-III) exhibited similar PEEP dependencies and distribution between the protocol groups formed on the basis of Crs. A wide interindividual scatter was observed in the overall Raw-S(T-III) relationship, which was primarily affected by Crs. Decreases in Raw with increasing PEEP were reflected in sharp falls in S(III) in Group HC, and in moderate decreases in S(III) in Group MC, whereas S(T-III) was insensitive to changes in airway caliber in Groups LC and HL. CONCLUSIONS: SIII assessed in the time domain and by volumetry provide meaningful information about alterations in airway caliber, but only within an individual patient. Although S(T-III) may be of value for bedside monitoring of the airway properties, its sensitivity depends on Crs. Thus, assessment of the capnogram shape should always be coupled with Crs when the airway resistance or oxygenation are evaluated.