SURGERY AND IMAGING - ADVANCES

N. Hakim, J.S. Crane, R. Canelo, E. Aboutaleb
, West London renal and transplant centre, Hammersmith Hospital, london/UNITED KINGDOM

Body: Introduction After kidney transplantation, surveillance of graft blood supply is critical. A delay in detecting compromised graft perfusion can impact on organ survival. Current practice involves using doppler ultrasound as the main tool to monitor vessel patency and graft perfusion and is performed repeatedly following kidney and pancreas transplantation. The implantable probe allows for easy attachment and safe, continuous monitoring of vascular anastomoses. It has been used in observing microvascular tissue transplants, free flaps and paediatric liver transplants but not yet in kidney transplantation. Methods The Implantable Doppler Cook-Swartz flow probe 20 MHz crystal is attached to a cuff and was placed in 5 live donor related kidney transplant patients. Our post-op monitoring protocol was as follows: Day 1: Monitor continuously, noting any noticeable change in signal. Day 2: Monitor once per hour. Day 3: Monitor every 2 hours. Day 4: Monitor every 3 hours. Day 5: Monitor every 4 hours. Discontinue after day 5. Remove probe on day 5-7. Probe removal requires a gentle traction on the wire; 1/10th lb (50g) pressure disengages the crystal from the cuff, which remains permanently in place around the vessel. There are no documented cases of removal damaging the anastomosis. Results All 5 transplants were followed as per protocol. Only a single Doppler ultrasound was ordered during the entire 5 admissions compared to frequent scans routinely ordered. There were no complications and all probes were straightforwardly removed. Conclusion The probe potentially saves precious organs. It can monitor continuously or periodically as required and can instantly identify flagging or loss of blood flow allowing earliest possible intervention. In a pre-emptive kidney transplant, urine output is misleading thus continuous doppler surveillance can be vital. It also confers other advantages including obviating the need for bulky doppler machines at the bedside, decreasing costly usage of radiological facilities (often out-of-hours) and removing wound infection risk from repeated duplex probe contact over the surgical wound.

Disclosure: All authors have declared no conflicts of interest.