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re-transplantation if necessary . A centre-specific study has also been conducted to assess the impact of ECMO following LTx , with a focus on patient outcomes . The findings unveiled several factors associated with the need for post-transplant ECMO , including vascular disease as the cause of transplantation , advanced donor age , and the requirement for cardiopulmonary bypass during the transplant procedure [ 39 ].
Hunt reviewed the risk factors and management strategies for PGD . Supportive care is crucial in managing PGD , and early initiation of ECMO has been shown to improve outcomes in certain patients . The study also discussed the potential benefits of ex-vivo lung perfusion platforms in reducing the risk of PGD and increasing lung transplant volume , although the impact on survival requires further investigation [ 40 ].
Van Slambrouck et al . provided a multidimensional understanding of PGD at various levels , including clinical , physiological , radiological , histological , and cellular . This comprehensive approach enhances our knowledge of acute lung failure in lung transplant recipients and provides insights for future therapeutic strategies [ 41 ]. Harano et al . examined the predictors and outcomes of early mortality in post-lung transplant patients who required ECMO for PGD . The study found that earlier recognition of PGD and prompt initiation of ECMO may improve outcomes in this patient population . Delayed initiation of ECMO after transplantation was associated with higher in-house and 3-year mortality rates [ 42 ].
These studies highlight the critical role of ECMO in managing severe PGD after LTx and heart transplantation . Early initiation of ECMO has been associated with improved outcomes , while delayed initiation or the use of VA ECMO for grade 3 PGD may increase the risk of mortality . Careful patient selection , timely recognition of PGD , and prompt initiation of appropriate ECMO support are crucial factors in optimizing outcomes in these high-risk patients .
ECMO configurations
The integration of ECMO has become an important component of LTx , offering diverse applications throughout various stages of the procedure . VV ECMO is commonly employed for patients experiencing hypercapnic or hypoxic respiratory failure , while VA ECMO may be necessary for those facing hemodynamic instability . During the intra-operative phase , VV ECMO can be either continued or switched to VA ECMO as required . Recent investigations have delved into the potential advantages of routine intra-operative ECMO , such as enhancing graft function , reducing primary graft dysfunction , and mitigating the effects of ischemia-reperfusion injury during the postoperative period [ 8 , 43 ].
Takahashi et al . assessed the outcomes of patients with grade 3 PGD who required ECMO support after LTx . The study found that the use of venoarterial ( VA ) ECMO for grade 3 PGD was associated with increased mortality compared to venovenous ( VV ) ECMO or non-ECMO treatment . This suggests that VA ECMO treatment for grade 3 PGD is a significant risk factor for mortality [ 44 ].
The impact of different cannulation methods for V-V ECMO was examined in a retrospective , multicentre study , in patients with severe respiratory failure caused by COVID-19 undergoing V-V ECMO . The study involved 435 adult patients from 17 centres , divided into three groups based on cannulation method : dual-site cannulation , cannula in the pulmonary artery , and cannula in the inferior vena cava . The findings indicated that using a single dual-lumen cannula positioned in the pulmonary artery via the internal jugular vein was associated with lower mortality rates compared to the other methods . However , it is important to consider the limitations of the study , and further research is necessary to validate these results [ 45 ]. Another study by Parker et al . compared atrio-femoral and femoro-atrial cannulation methods in V-V ECMO . Atrio-femoral cannulation showed 13.5 % higher recirculation under ideal conditions , with flow patterns resembling normal physiology . Femoro-atrial cannulation led to multiple vortices and increased turbulent kinetic energy at higher flow rates . Factors such as occlusion of side holes and inferior vena cava inflow affected recirculation . The choice of cannulation should consider drainage issues , and the proximity of the cannula tip did not significantly impact recirculation [ 46 ].
Ruszel et al . in their study found that among patients undergoing LTx , approximately half required assistance with ECMO or cardiopulmonary bypass . Central ECMO was associated with higher survival rates compared to no support , peripheral ECMO , or cardiopulmonary bypass . However , the use of support devices increases the risk of acute kidney injury and thromboembolic complications . The study recommended favouring central ECMO over other methods and discontinuing cardiopulmonary bypass during LTx [ 32 ].
ECMO strategies Kim et al . found that awake patients on ECMO had better postoperative outcomes compared to non-awake patients . The awake group experienced shorter stays in the intensive care unit , longer periods free from ventilator support , higher gait ability after transplantation , and improved lung function at 6 months and 1 year . Furthermore , the awake group had significantly lower mortality rates at 6 months and 1 year compared to the non-awake group . These findings suggest that the awake ECMO strategy may be beneficial for patients with end-stage lung disease awaiting transplantation [ 47 ].
Patients with end stage lung disease often succumb to intubation and the common resulting complications including critical illness polyneuropathy , making it difficult to maintain the physical function that is required for impending lung transplantation . Because limited functional status or poor rehabilitation potential are absolute contraindications to lung transplantation , efforts to minimize loss of strength and function are crucial [ 48 ].
Active rehabilitation and ambulation while on ECMO are proposed for carefully selected patients , and should be delivered by highly trained multidisciplinary teams typically led by physical therapists [ 49 – 52 ]. Published procedures and algorithms for patient selection and progressive mobilization , as well as ECMO configurations , are available to facilitate the uptake of this practice [ 52 – 54 ].
Interest in awake and ambulatory ECMO is evident in early published descriptions of small cohorts of bridge to transplant