DIY Isolated Lung Set-up: Construction and Troubleshooting

Ex-vivo lung preparations have the advantage of being able to study the responses of the lung to drugs or other interventions in a controlled environment without any hemodynamic changes or confounding variables such as a humoral or neuronal input. Assessments that can be taken over time include pulmonary artery pressure (PAP), pulmonary vein pressure (PVP) and airway pressure (AWP). Figure shows a schematic of the lung set-up (numbers in brackets refer to parts of the set-up). A heated reservoir [1] contains a balanced salt perfusate solution (NaCl 119 mM, NaHCO3 24 mM, Glucose 5.5 mM, CaCl2 1.6 mM, KCl 4.7 mM, MgSO4 1.17 mM, NaPO4 1.18 mM) with 4% bovine serum albumin. A sufficiently high and stable glucose concentration is important for the viability of the lung. Thus, due to its glucose metabolism, glucose concentrations must be monitored continuously, or at least every hour, and adjusted by glucose infusions. Stable temperature of the perfusate (37.0–37.5°C) is achieved with a heating plate [2], heating coil and heated bubble trap, with the coil and bubble trap heated by a separate circulating water bath [3]. A roller pump [4], with speed set to 40 cc · min−1 · kg−1 body weight and controlled manually or remotely, pumps the perfusate through the heating coil [5] and the heated bubble trap [6] to the inflow cannula placed in the pulmonary artery. The temperature of the heating coil and bubble trap needs to be adjusted according to the pump speed. To keep the lung warm and moist, it is hung above a heated water bath (~ 48°C) [7]. An outflow cannula placed into the left ventricle connects the pulmonary circulation back to the reservoir to recycle the perfusate. The lung is positive pressure ventilated by a rodent ventilator with, e.g. 30% O2, 5% CO2 and 65% N2, and a tidal volume VT = 10 cc · kg−1 body weight. The positive end-expiratory pressure (PEEP) is set to 2–3 mmHg by a water lock. The pressure transducers, placed at the same height as the lung, are attached to the inflow, outflow and the ventilator to continuously record PAP, PVP and AWP, respectively. They are connected to a data acquisition system via bio amplifiers. A framework made from aluminium rods and rod clamps provides three-dimensional stability. Weekly cleaning of the setup with 5% bleach and 5% HCl is advised to avoid contamination. In summary, the described self-made isolated lung set-up provides maximal flexibility for future adjustments, while being an affordable alternative to more expensive premade set-ups. Support or Funding Information This work was supported, in part, by institutional funds, NIH grant (5R01 HL123227), and a Merit Review Award (I01 BX003482) from the U.S. Department of Veterans Affairs Biomedical Laboratory R&D Service. Isolated lung set-up This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.