Microdialysis and CO2 sensors detect pancreatic ischemia in a porcine model

Background: Pancreatic transplantation is associated with a high rate of early postoperative graft thrombosis. If a thrombosis is detected in time, a potentially graft-saving intervention can be initiated. Current postoperative monitoring lacks tools for early detection of ischemia. The aim of this study was to investigate if microdialysis and tissue pCO2 sensors detect pancreatic ischemia and whether intraparenchymal and organ surface measurements are comparable. Methods: In 8 anaesthetized pigs, pairs of lactate monitoring microdialysis catheters and tissue pCO2 sensors were simultaneously inserted into the parenchyma and attached to the surface of the pancreas. Ischemia was induced by sequential arterial and venous occlusions of 45-minute duration, with two-hour reperfusion after each occlusion. Microdialysate was analyzed every 15 minutes. Tissue pCO2 was measured continuously. We investigated how surface and parenchymal measurements correlated and the capability of lactate and pCO2 to discriminate ischemic from non-ischemic periods. Results: Ischemia was successfully induced by arterial occlusion in 8 animals and by venous occlusion in 5. During all ischemic episodes, lactate increased with a fold change of 3.2–9.5 (range) in the parenchyma and 1.7–7.6 on the surface. Tissue pCO2 increased with a fold change of 1.6–3.5 in the parenchyma and 1.3–3.0 on the surface. Systemic lactate and pCO2 remained unchanged. The area under curve (AUC) for lactate was 0.97 (95% confidence interval (CI) 0.93–1.00) for parenchymal and 0.90 (0.83–0.97) for surface (p<0.001 for both). For pCO2 the AUC was 0.93 (0.89–0.96) for parenchymal and 0.85 (0.81–0.90) for surface (p<0.001 for both). The median correlation coefficients between parenchyma and surface were 0.90 (interquartile range (IQR) 0.77–0.95) for lactate and 0.93 (0.89–0.97) for pCO2. Conclusions: Local organ monitoring with microdialysis and tissue pCO2 sensors detect pancreatic ischemia with adequate correlation between surface and parenchymal measurements. Both techniques and locations seem feasible for further development of clinical pancreas monitoring.publishedVersio

First Experience With Rectus Sheath Block for Postoperative Analgesia After Pancreas Transplant: A Retrospective Observational Study

Background Standard of care for postoperative analgesia after pancreas transplant has been thoracic epidural analgesia (TEA). A high incidence of venous graft thrombosis necessitated a change to a more aggressive anticoagulation protocol. To minimize the risk of epidural hemorrhages, we changed from TEA to rectus sheath block (RSB) in 2017. Methods From June 2016 to December 2017, a total of 29 consecutive pancreas transplant recipients were included. Sixteen were treated with TEA and 13 were treated with RSB. In the TEA group, the catheter was inserted before induction of general anesthesia, and an epidural infusion was started intraoperatively. An ultrasound-guided RSB was performed bilaterally, and a bolus of local anesthetic was administered before an 18G catheter was inserted. The patients received intermittent local anesthetic boluses every 4 hours in addition to an intravenous patient-controlled analgesia with oxycodone. Both groups received oral acetaminophen and additional rescue opioids. Results The administered amount of intravenous morphine equivalents (MEQ) was not significantly different between the RSB and TEA groups. The median MEQ consumption per day during the stay at the surgical ward was 23 mg MEQ/d (interquartile range [IQR], 14–33 mg MEQ/d) in the TEA group compared with 19 mg MEQ/d (IQR, 14–32 mg MEQ/d) in the RSB group (P = .4). The duration of the pain catheters was significantly longer in the RSB group. We had no complications related to insertion, use, or removal of the RSB or the TEA catheters, and overall patient satisfaction and comfort was good. Conclusion Compared with TEA, RSB was equally effective and safe for postoperative analgesia in heavily anticoagulated pancreas transplant patients.publishedVersio

First Experience With Rectus Sheath Block for Postoperative Analgesia After Pancreas Transplant: A Retrospective Observational Study

Background Standard of care for postoperative analgesia after pancreas transplant has been thoracic epidural analgesia (TEA). A high incidence of venous graft thrombosis necessitated a change to a more aggressive anticoagulation protocol. To minimize the risk of epidural hemorrhages, we changed from TEA to rectus sheath block (RSB) in 2017. Methods From June 2016 to December 2017, a total of 29 consecutive pancreas transplant recipients were included. Sixteen were treated with TEA and 13 were treated with RSB. In the TEA group, the catheter was inserted before induction of general anesthesia, and an epidural infusion was started intraoperatively. An ultrasound-guided RSB was performed bilaterally, and a bolus of local anesthetic was administered before an 18G catheter was inserted. The patients received intermittent local anesthetic boluses every 4 hours in addition to an intravenous patient-controlled analgesia with oxycodone. Both groups received oral acetaminophen and additional rescue opioids. Results The administered amount of intravenous morphine equivalents (MEQ) was not significantly different between the RSB and TEA groups. The median MEQ consumption per day during the stay at the surgical ward was 23 mg MEQ/d (interquartile range [IQR], 14–33 mg MEQ/d) in the TEA group compared with 19 mg MEQ/d (IQR, 14–32 mg MEQ/d) in the RSB group (P = .4). The duration of the pain catheters was significantly longer in the RSB group. We had no complications related to insertion, use, or removal of the RSB or the TEA catheters, and overall patient satisfaction and comfort was good. Conclusion Compared with TEA, RSB was equally effective and safe for postoperative analgesia in heavily anticoagulated pancreas transplant patients

Validating the US pancreas donor risk index in a Norwegian population, a retrospective observational study

OBJECTIVES Despite advances in immunosuppression and surgical technique, pancreas transplantation is still associated with a significant graft loss rate. The Pancreas Donor Risk Index (PDRI) is a pre-transplant scoring tool derived from a US population. We sought to validate the PDRI in a Norwegian population. METHODS We retrospectively retrieved donor data for 344 pancreas transplants undertaken in Norway between 2000 and 2019, utilising the Scandiatransplant database, and matched these to the respective recipients. The PDRI score was calculated for each transplanted pancreas, these were then stratified into quintiles. The association between the PDRI quintiles and 1-year graft survival was calculated, and this was repeated for the different types of pancreas transplantation. The association between PDRI as a continuous variable, and graft survival was determined. Donor and recipient data were compared to the original US population. RESULTS The overall 1-year graft survival was 82.7%. There were no significant differences in survival between the different PDRI quintiles. When viewed as a continuous variable, increased PDRI score was not associated with decreased graft survival. Significant differences between the Norwegian and US populations were found. CONCLUSIONS When applied to a Norwegian population, the PDRI score was unable to predict 1-year graft survival

Early detection of complications in pancreas transplants by microdialysis catheters, an observational feasibility study

Background Despite advances in immunosuppression and surgical technique, pancreas transplantation is encumbered with a high rate of complication and graft losses. Particularly, venous graft thrombi occur relatively frequently and are rarely detected before the transplant is irreversibly damaged. Methods To detect complications early, when the grafts are potentially salvageable, we placed microdialysis catheters anteriorly and posteriorly to the graft in a cohort of 34 consecutive patients. Glucose, lactate, pyruvate, and glycerol were measured at the bedside every 1–2 hours. Results Nine patients with graft venous thrombosis had significant lactate and lactate–to-pyruvate-ratio increases without concomitant rise in blood glucose or clinical symptoms. The median lactate in these patients was significantly higher in both catheters compared to non-events (n = 15). Out of the nine thrombi, four grafts underwent successful angiographic extraction, one did not require intervention and four grafts were irreversibly damaged and explanted. Four patients with enteric anastomosis leakages had significantly higher glycerol measurements compared to non-events. As with the venous thrombi, lactate and lactate-to-pyruvate ratio were also increased in six patients with graft surrounding hematomas. Conclusions Bedside monitoring with microdialysis catheters is a promising surveillance modality of pancreatic grafts, but differentiating between the various pathologies proves challenging