Selective Recruitment of Large Lower Lobe Atelectasis on Donor Back Table in Rejected Donor Lungs

Technical Advances Targeting Multiday Preservation of Isolated Ex Vivo Lung Perfusion

Indications for ex vivo lung perfusion (EVLP) have evolved from assessment of questionable donor lungs to treatment of some pathologies and the logistics. Yet up to 3 quarters of donor lungs remain discarded across the globe. Multiday preservation of discarded human lungs on EVLP platforms would improve donor lung utilization rates via application of sophisticated treatment modalities, which could eventually result in zero waitlist mortality. The purpose of this article is to summarize advances made on the technical aspects of the protocols in achieving a stable multiday preservation of isolated EVLP. Based on the evidence derived from large animal and/or human studies, the following advances have been considered important in achieving this goal: ability to reposition donor lungs during EVLP; perfusate adsorption/filtration modalities; perfusate enrichment with plasma and/or donor whole blood, nutrients, vitamins, and amino acids; low-flow, pulsatile, and subnormothermic perfusion; positive outflow pressure; injury specific personalized ventilation strategies; and negative pressure ventilation. Combination of some of these advances in an automatized EVLP device capable of managing perfusate biochemistry and ventilation would likely speed up the processes of achieving multiday preservation of isolated EVLP.

Ventilation during ex vivo lung perfusion, a review

Evidence suggests that ventilation during ex vivo lung perfusion (EVLP) with a 'one-size-fits-all' strategy has the potential to cause lung injury which may only become clinically relevant in marginal lung allografts. EVLP induced- or accelerated lung injury is a dynamic and cumulative process reflecting the interplay of a number of factors. Stress and strain in lung tissue caused by positive pressure ventilation may be exacerbated by the altered properties of lung tissue in an EVLP setting. Any pre-existing injury may alter the ability of lung allografts to accommodate set ventilation and perfusion techniques on EVLP leading to further injury. This review will examine the effects of ventilation on donor lungs in the setting of EVLP. A framework for developing a protective ventilation technique will be proposed.

Successful lung transplantation after prone positioning in an ineligible donor: a case report

Atelectasis is a reversible factor in hypoxemia among brain-dead donors. In ineligible donors, prone positioning reverses atelectasis and improves oxygenation. We present a successful lung transplantation after salvaging a previously unviable lung. A 37-year-old woman presented with acute pontine hemorrhage that progressed to brain death. The initial partial pressure of oxygen (PaO₂)/fraction of inspired oxygen (FiO₂) ratio of the donor’s lung was 342 mmHg. The PaO₂/FiO₂ ratio dropped to 49 mmHg due to atelectasis. There was no improvement despite recruitment maneuvers, bronchoscopy, and chest percussion. After placing the donor in the prone position for four hours, electrical impedance tomography showed improved atelectasis. The donor did not experience hemodynamic instability. The lung was transplanted into a patient with Kartagener’s syndrome with situs inversus. The surgical procedure was uneventful. He was successfully weaned from the mechanical ventilator on the second-day post-transplantation and was discharged from the hospital after 4 weeks.

Hyperinflation With Pulmonary Dysfunction in Donor Lungs With Smoking History During Lung Perfusion

BACKGROUND

Donor lungs with smoking history are perfused in ex vivo lung perfusion (EVLP) to expand donor lung pool. However, the impact of hyperinflation of perfused lungs in EVLP remains unknown. The aim of this study was to investigate the significance of hyperinflation, using an ex vivo measurement delta V_T, during EVLP in smoker's lungs.

MATERIALS AND METHODS

Seventeen rejected donor lungs with smoking history of median 10 pack-years were perfused for 2 h in cellular EVLP. Hyperinflation was evaluated by measuring delta V_T = inspiratory - expiratory tidal volume (V_T) difference at 1 h. All lungs were divided into two groups; negative delta V_T (n = 11, no air-trapping pattern) and positive delta V_T (n = 6, air-trapping pattern). Transplant suitability was judged at 2 h. By using lung tissue, linear intercept analysis was performed to evaluate the degree of hyperinflation.

RESULTS

The positive delta V_T group had significantly lower transplant suitability than the negative delta V_T group (16 versus 81%, P = 0.035). The positive delta V_T group was significantly associated with lower partial pressure of oxygen/fraction of inspired oxygen ratio ratio (278 versus 356 mm Hg, P = 0.049), higher static compliance (119 versus 98 mL/cm H₂O, P = 0.050), higher lung weight ratio (1.10 versus 0.96, P = 0.014), and higher linear intercept ratio (1.52 versus 0.93, P = 0.005) than the negative delta V_T group.

CONCLUSIONS

Positive delta V_T appears as an ex vivo marker of ventilator-associated lung hyperinflation of smoker's lungs during EVLP.