Temporary intravascular shunting improves survival in a hypothermic traumatic shock swine model with superior mesenteric artery injuries

Background

Repairs of superior mesenteric artery (SMA) injuries are difficult and often result in high mortality. Our group has employed temporary intravascular shunts (TIVS) as a damage control procedure in a SMA transection model and hypothesized that TIVS would improve survival when compared with primary vascular anastomosis in the setting of a damage control surgery.

Methods

The SMA was clamped and completely transected while pigs were hemorrhaged to a mean arterial pressure of 40 mmHg and maintained in shock for 30 minutes. Cold lactated Ringer's solution was gradually infused while the abdomen was open to induce hypothermia. Animals were randomized to control (no resuscitation), primary anastomosis (PA), or temporary shunting (TS) of the SMA. Animals were resuscitated for 6 hours with the shed blood and lactated Ringer's solution. Delayed anastomosis was performed in TS animals after resuscitation. Surviving animals were humanely killed 2 days after operation. Systemic hemodynamic parameters were recorded hourly. The ileum was harvested at the end of resuscitation and experiment for pathologic evaluation.

Results

All animals suffered extreme physiologic conditions: hypothermia, severe acidosis, hypotension, and depressed cardiac output and oxygen delivery. Control animals suffered 100% mortality. Compared with the PA group, TS animals required less resuscitation fluid, retained higher SMA flow rates, normalized lactate levels faster, suffered less severe intestine histopathology, and had greater early survival.

Conclusion

Damage control surgery in the setting of SMA transection seems better managed with TS than with PA. Further validation of this model is required before generalization to human applications.