To investigate the operation stability and protective effect of portable in situ mechanical perfusion device (IMPD) on donor organs from large animals without heartbeat.

Six healthy and clean Bama miniature pigs got open surgery through a midline incision after anesthesia, and were spiled through the abdominal aorta and inferior vena cave respectively, and connected to self-developed portable IMPD. The heart was suddenly arrested by intravenous injection of potassium chloride, and no relapse was observed in 5 min. The mechanical perfusion of animal organs was performed by starting the device at room temperature (37 ℃). The rotational speed and perfusion flow of the blood pump were adjusted to maintain the venous blood oxygen saturation at 60%-70%. The Bama miniature pigs were got perfusion for 12 h ( every 2 h for the observation point in time), during which the equipment pipeline flow, pump rotation speed and flow rate/speed ratio operation parameters were recorded and the liver and kidney function and arterial blood gas analysis were detected. The common bile duct, liver, kidney and intestine tissues were obtained and observed in HE staining to assess the pathological changes. One-way repeated measures analysis of variance was used to compare the operating parameters at different time points, hepatic and renal function, and internal environment indexes between the 2 groups, and that between groups with Least Significant Difference. P<0.05 was considered statistically significant.

The 12 h perfusion was expected to be completed in all experiments. During the perfusion process, equipment operated stably without failure or shutdown accident. Pipeline flow, blood pump speed and flow/speed ratio were all stable. ALT, total bilirubin (TBIL) and gamma glutamyltransferase (GGT) were stable, and the preoperative physiological values were no significant difference from other time points (beginning to the end of perfusion) (all P>0.05). AST increased slowly after the beginning of perfusion, and AST was (73±21), (90±30) and (114±48) U/L at 8, 10 and 12 h after perfusion, respectively, with statistical significance compared with the preoperative physiological values (all P<0.05). Within 5 min of cardiac arrest, lactic acid reached the peak at the beginning of perfusion, and there was a significant difference between the value of lactic acid and the peak value from 8th hour of perfusion (all P<0.05). There were significant differences in K⁺ concentration levels at each time point from the 2nd hour of perfusion compared with the beginning of perfusion (all P<0.05). ALT, TBIL, GGT, BUN, creatinine, blood gas analysis indexes, concentrations of Na⁺ , Ca²⁺ and Cl^- concentrations were stable, and there was no statistical significance in the values from the beginning to the end of perfusion compared with the preoperative physiological values (all P>0.05). Bile formation and urine production continued from the beginning of perfusion. The liver remained ruddy in appearance, soft in texture and sharp edge during 12 h of donor liver perfusion. After the perfusion, the histological results of the common bile duct, liver, kidney and small intestine showed that the histological structure was intact, without congestion, and no signs of substantial area necrosis.

Portable IMPD can stably perfuse the donor organs of non-heartbeat pigs for 12 h, and can maintain the common bile duct, liver, kidney and small intestine well.