Donor hepatectomy: INR elevation
Advanced, Clinical - Hepatic, Special Problems or Issues in Anesthesiology
The liver is responsible for synthesis of clotting factors and other important proteins involved with regulating the coagulation cascade. Therefore, even in patients with a normal preoperative coagulation profile, alterations in bleeding and thrombosis have been observed following donor hepatectomy. This becomes important when considering perioperative pain management in these patients in regards to epidural analgesia.
Siniscalchi et al. studied 30 patients (all ASA 1 with normal pre-op coagulation profile) underwent pre-op epidural placement for post-op pain management. The epidural catheter was removed when PT was greater than 60%, aPTT was less than 1.24, and platelets were greater than 100000/mm3. Estimated blood loss, amount of IV fluids administered, duration of surgery, and weight of resected portion of liver were all studied. Each patient’s PT, aPTT, platelet count and fibrinogen were measured pre-op, on admission to recovery room and daily until the values returned to normal range.
The changes in PT remained significant in relation to pre-operative values until POD#5 (as demonstrated in the figure below) and peaked on POD#1. Immediately following surgery, estimated blood loss and amount of fluids administered seemed to be related to greatest changes in PT, suggesting dilution and consumption of factors plays a role in the initial postoperative coagulation dysfunction. However, by POD#1 the weight of the resected portion of liver had the strongest correlation with change in post-op PT values, suggesting the imbalance in synthetic function due to a greater amount of liver being resected plays an important role post-operatively. None of the patients in this study developed complications related to the epidural catheter, and all met criteria for epidural catheter removal by POD#4.
Choi et al. evaluated coagulation profiles and epidural catheter use in 360 patients undergoing donor hepatectomy. 242 of the patients underwent epidural analgesia. Platelet count, PT, and aPTT were all shown to be altered by POD#1 but resolved by POD#7. Nine donors (2.5%) had an INR > 2.0 post-operatively. No epidural hematoma was observed.
In summary, all patients will have an increase in the INR after donor hepatectomy in the postoperative period. The INR in the majority of patients will not return to normal for at least seven days . The effects of hepatectomy on post-op coagulation should be considered prior to administration of epidural analgesia.