Hypothermic preservation of isolated rat lungs in modified bicarbonate buffer, EuroCollins solution or St Thomas' Hospital cardioplegic solution.
OBJECTIVE
Inadequate preservation solutions limit lung storage times and, consequently, transplant programs. To address this problem we established an isolated, ventilated and perfused rat lung preparation. Here we report the effects of hypothermic storage in EuroCollins solution, St Thomas' Hospital cardioplegic solution and a modified bicarbonate buffer solution.


METHODS
Lungs from male Wistar rats (230-330 g) were perfused via the pulmonary artery with modified bicarbonate buffer (37 degrees C, 15 ml/min, constant flow) and ventilated by positive pressure (tidal volume:1.6-1.8 ml, 80 breaths/min). Vascular resistance (pulmonary artery pressure:perfusate flow ratio) and airways compliance (tidal volume:tracheal pressure ratio) were measured. After a control perfusion period (20 min), lungs were flushed with, then immersed in, bicarbonate buffer (4 degrees C) for varying periods (0-24 h). After storage, lung function was assessed during 20 min reperfusion. Having established a suitable period for study, storage in EuroCollins, St Thomas' Hospital cardioplegic solution or bicarbonate buffer were compared.


RESULTS
Pulmonary compliance (ml/cmH2O) was significantly (P < 0.05) reduced in lungs stored for 6 h in modified bicarbonate buffer (0.026 +/- 0.008), EuroCollins solution (0.013 +/- 0.002) or St Thomas' Hospital solution (0.025 +/- 0.005) compared to unstored lungs (0.068 +/- 0.007). Vascular resistance, (1.32 +/- 0.13 cmH2O/ml per min) in unstored lungs, was similar in lungs stored in St Thomas' Hospital solution but increased significantly in lungs stored in modified bicarbonate buffer (3.22 +/- 0.78 cmH2O/ml per min) or EuroCollins solution (4.66 +/- 0.57 cmH2O/ml per min).


CONCLUSIONS
Hypothermic storage of rat lungs for 6 h in modified bicarbonate buffer or St Thomas' Hospital solution causes less increase in vascular resistance on reperfusion than EuroCollins solution.
Featherstone
R L
RL
Cardiovascular Research, The Rayne Institute, St Thomas' Hospital, London, UK. rfeather@rayne.umds.ac.uk
Kelly
F J
FJ
Shattock
M J
MJ
Hearse
D J
DJ
Chambers
D J
DJ
D000818:Animals; D001639:Bicarbonates; D002021:Buffers; D002122:Calcium Chloride; D002314:Cardioplegic Solutions; D006982:Hypertonic Solutions; D008168:Lung / Q000503:physiopathology; D016040:Lung Transplantation; D008274:Magnesium; D008297:Male; D009926:Organ Preservation / Q000379:methods*; D019188:Organ Preservation Solutions; D011189:Potassium Chloride; D051381:Rats; D017208:Rats, Wistar; D012965:Sodium Chloride; D013997:Time Factors
D001639:Bicarbonates; D002021:Buffers; D002314:Cardioplegic Solutions; C037096:Euro-Collins' solution; D006982:Hypertonic Solutions; D019188:Organ Preservation Solutions; C041711:St. Thomas' Hospital cardioplegic solution; D012965:Sodium Chloride; D011189:Potassium Chloride; D008274:Magnesium; D002122:Calcium Chloride