Unexpected Intraoperative “Oozing”

A 64-yr-old woman (American Society of Anesthesiologists physical status 3) is scheduled for a craniotomy for clipping of a large aneurysm. Her history includes hypertension, obesity (130kg and 5′6″), and insulin-dependent diabetes mellitus. She is alert and orientated and moves all limbs. She claims her exercise tolerance is good, meaning that she can walk half a flight of steps without stopping or getting breathless. The size of the aneurysm worries the surgeon. Therefore, he has requested that a femoral arterial sheath be placed by the neuroradiology team in the femoral artery before the surgical incision. The reason for this is that, should clipping of the aneurysm prove to be impossible or dangerous, coiling of the aneurysm can then be attempted via the femoral artery. You anesthetize her in a routine manner and the anesthetic proceeds according to plan with stable vital signs. The interventional radiologist cannulates the femoral artery. After that, he infuses the femoral sheath with a heparinized solution (500 ml normal saline with 2,000 units of heparin) under pressure via a pressure bag (Infusable Pressure Infusor; Vital Signs,Totowa, NJ).The solution drips very slowly into the femoral artery via a 60 drops/ml Piggyback Microdrip with a Clair clamp controlling the rate (1–2 drops every minute) (LifeShield; Hospira, Inc., Lake Forest, IL). There is no transducer system attached. The patient is turned 180 degrees from the anesthetic machine and the surgery begins. After 90 min, the aneurysm is exposed. The surgeon complains that there is a lot of oozing in the surgical site and that he has difficulty maintaining adequate hemostasis. He asks you if the preoperative coagulation was normal. You answer that it was and tell him that the liver enzymes were also within normal limits. He says, “Please give her some fresh frozen plasma (FFP) and tell me when you have given it.” You are at a loss to understand the cause of the oozing, but order the FFP as soon as possible. You send off new coagulation studies (international normalized ratio, prothrombin time, and partial thromboplastin time) and an arterial blood gas (ABG). You also place 5ml of her blood in a glass tube. The results from the ABG, including electrolytes and blood sugar, come back within normal limits. However, the blood in the glass tube is still liquid, even after 15 min. Five minutes later, the FFP arrives and you infuse it quickly. The surgeon reports no improvement. You tell him that you are still waiting for the coagulation results from the lab. You are at a loss to understand what is going on, and the surgeon is unhappy. What do you think could be the cause of the oozing, and what will you do?