Continuous Endogenous Exhaled CO Monitoring by Laser Spectrometer in Human EVLP Before Lung Transplantation

Area of Science:

• Pulmonary Medicine
• Transplantation Immunology
• Biomedical Engineering

Background:

• Endogenous carbon monoxide (CO) production is influenced by inflammation and ischemia-reperfusion injury.
• Precise measurement of exhaled endogenous CO (eCO) is achievable using laser spectrometry.
• Lung transplantation outcomes can be improved by better graft assessment.

Purpose of the Study:

• To assess exhaled endogenous CO (eCO) levels in human lung grafts during normothermic ex-vivo lung perfusion (EVLP).
• To compare eCO levels between accepted and rejected lung grafts.
• To correlate eCO values with EVLP parameters and recipient post-operative outcomes.

Main Methods:

• A laser spectrometer (ProCeas®) was connected in bypass to the ventilation circuit of 21 consecutive EVLP lung grafts.
• eCO levels were continuously monitored during EVLP.
• eCO values were compared between transplanted and rejected grafts, and correlated with EVLP parameters (glucose consumption, lactate production, edema, PO2/FiO2 ratio) and post-operative outcomes (Primary Graft Dysfunction score, ICU stay).

Main Results:

• Two out of 21 lung grafts were rejected, showing a tendency for higher eCO levels (0.358 ± 0.52 ppm) compared to transplanted lungs (0.240 ± 0.76 ppm).
• During EVLP, eCO correlated with glucose consumption and lactate production, but not with edema or the PO2/FiO2 ratio.
• Patients receiving grafts with high eCO levels (>0.235 ppm) during EVLP had a Primary Graft Dysfunction score of 3 within 72 hours and tended to have longer ICU stays.

Conclusions:

• Continuous eCO monitoring during EVLP is feasible.
• eCO may serve as an early and additional marker for evaluating lung graft viability.
• eCO levels can provide valuable information for post-operative resuscitation care and predicting graft dysfunction.