A donor PaO2/FiO2 < 300 mm Hg does not determine graft function or survival after lung transplantation

https://doi.org/10.1016/j.healun.2019.08.021Get rights and content

BACKGROUND

A donor arterial PO2/FiO2 (P/F ratio) of less than the 300 threshold would frequently result in either exclusion of the donor or placement of the lungs on ex vivo lung perfusion (EVLP). The aim was to investigate the veracity of the P/F ratio threshold of 300 for donor lung acceptability.

METHODS

In 93 brain dead lung donors, arterial blood gases were drawn in the intensive care unit (ICU) just before procurement and each of the 4 donor pulmonary veins in the operating room (OR). No donor lungs were rejected for transplantation based on the last ICU or OR P/F ratio, and EVLP was not used. The recipients were followed up 6 and 12 months following transplantation.

RESULTS

There were 93 recipients of bilateral lung transplantation. An arterial P/F ratio of < 300 was largely driven by a low P/F ratio in the lower lobes. There were no differences between the recipients receiving donor lungs where the ICU P/F ratio was < 300 compared with ≥ 300 in the time to extubation, grade of primary graft dysfunction, pulmonary function at 6 and 12 months, and 12-month survival.

CONCLUSIONS

From this study:(1) If a donor P/F threshold of 300 was adhered to, 36% would have been rejected, and (2) The donor P/F ratio threshold of 300 is excessively conservative and results in the wastage of donor lungs and the application of unnecessary EVLP.

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Methods

This study was a single site, prospective trial designed to investigate the relationship between the donor and recipient P/F ratios at various time points during and following lung transplantation and the effect on long-term outcomes. Donor lungs that were accepted for transplantation between November 17, 2014 and January 28, 2017 were included in the study. The donor assessment was conducted according to standard Australian processes. This study was approved by the Alfred Human Research Ethics

Donor characteristics

There were 93 donors (mean age 41.7 ± 16.6 years, 54.8% male, 53.8% smoking history) and 93 recipients (mean age 55.6 ± 13.2 years, 60.2% male) included in the study. Donor, intraoperative, and recipient clinical characteristics are displayed in Table 1. Median donor ventilation duration was 64 hours (IQR 36-92), and the mean time to procurement from donor death was 23.0 ± 11.3 hours.

Donor P/F ratio

Of the 93 donor lungs, 81 (87.1%) had a P/F ratio of ≥ 300, and 12 (12.9%) had a P/F ratio of < 300 in the ICU

Discussion

The key point of this study is that in carefully selected cases, the donor P/F ratio threshold of 300 for acceptability for transplantation can be transgressed without deleterious impact on survival within the first year after transplantation. In addition, the time to extubation, incidence of PGD, and pulmonary function at 6 and 12 months is not influenced by this single measure. What this study does not reveal is the lowest P/F ratio from the arterial line in the ICU that would be consistent

Disclosure statement

The authors have no conflicts of interest to disclose.

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These authors contributed equally to this work.

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