Maintaining Lung Recruitment During Apnea Testing for Brain Death Evaluation

1. Maintaining Lung Recruitment During Apnea Testing for Brain Death Evaluation Jennifer Hubbard, MD Assistant Professor of Surgery UCSF Fresno, Fresno, CA

2. Disclosures Travel expenses and conference registration provided by CTDN No vested interest in products presented

3. Background *http://optn.transplant.hrsa.gov/ • Lung retrieval rates are historically low • 2013* • 8,268 deceased donors • 1,896 lung donors (23%) • 7,547 kidney donors (91%)

4. CRMC & CTDN • ACS-verified Level 1 trauma center • 2012 • Only 5 lung transplants from 29 donors (17%)

5. Why the low rates? • Brainstorming between clinicians, CTDN coordinator, RT • Maybe due to low P:F ratios

6. Background 1. Thabut G, Mal H, et al. Influence of donor characteristics on outcome after lung transplantation: a multicenter study. J Heart Lung Transplant. 2005 Sep;24(9):1347-53. 2. Snell GI, Westall GP. Selection and management of the lung donor. Clin Chest Med. 2011 Jun;32(2):223-32. • Low P:F ratios • Ratio of the PaO2 to FiO2 • Significantly associated with organ recipient prognosis1 • Most transplant surgeons require a P:F ratio of >300 on a PEEP of 5 for eligibility2 • Things that may affect P:F ratio • Apnea testing during brain death evaluation

7. American Academy of Neurology Guidelines for the Determination of Brain Death (2010) • Clinical exam • Coma • Absence of brain stem reflexes • Apnea • Absence of a breathing drive is tested with a CO2 challenge • +/- ancillary tests

8. AAN Guidelines for Apnea Testing • Connect a pulse oximeter and disconnect the ventilator • Deliver 100% O2, 6 l/min, into the trachea • Option: place a cannula at the level of the carina • Look closely for respiratory movements • Abdominal or chest excursions that produce adequate tidal volumes • Measure arterial PO2, PCO2, and pH after approximately 8 minutes  reconnect the ventilator

9. Background • Improve P:F ratio by modifying apnea testing protocol • Decrease alveolar collapse • Decrease variability in practice • T-piece • O2 cannula inserted in ETT • CPAP on ventilator • Disconnecting to room air

10. Hypothesis Apnea testing for brain death evaluation on CPAP will improve P:F ratios, decrease alveolar collapse and improve lung retrieval/transplantation rates

11. Initial Method • CPAP on ventilator • Set to CPAP mode • No need to disconnect • Problem • Override

12. Ingenuity: Is there a better way? • CPAP machines from the floor • Poor use of resources • Flow-inflating bag • System routinely used for neonates

15. Flow-inflating Bag • Advantages • Ease of use • Maintains recruitment of alveoli • Inexpensive • Disadvantages • Disconnect from circuit • Very brief • Need for training of RTs and MDs

16. Implementation • Training & Education • RTs • Mandatory monthly education (online didactic and hands-on) • Minimal resistance • MDs • “Mandated” by Chief of Surgery and Director of Medical ICU • Initially not accepted by all • Data shown to MICU director • Uniformly used after about 2 years

17. 2010 - 2014 • Retrospective review of all patients undergoing apnea testing during brain death evaluation • Demographics • Mechanism of brain injury • Direct torso trauma • Smoking • Pneumonia/antibiotics • Deemed exempt by IRB

18. Results

19. Limitations • Small sample size • Other protocol changes • Increased use of Bilevel Mode (APRV) • Possible improved adherence to other OPO protocols

20. Conclusions • CPAP via flow-inflating bag • Improves oxygenation and lung donor rates • Inexpensive • Easy to use • No apparent “down side” • Recommend all apnea testing via CPAP

21. Acknowledgements Wade Veneman, RRT