Evaluation and management

The etiologies of postoperative hemorrhage are numerous :

1) Patients that are on antiplatelet agents or anticoagulants such as Coumadin preoperatively tend to have problems with postoperative bleeding.

2) Individuals with known familial clotting defects such as von Willebrand's disease, hemophilia A or B, etc., clearly have problems with postoperative hemorrhage.

3) Individuals who have undergone reoperation, because of the extensive dissection required and the usually longer bypass run, bleed much more in the postoperative state.

4) Patients that have prolonged complicated operations have an increased incidence of postoperative bleeding. This is due to the increased destruction of platelets and clotting factors by the cardiopulmonary pump apparatus.

5) Technical factors, such as a leak in a suture line or poorly tied ligature, can produce brisk postoperative hemorrhage.

6) Individuals who suffer transfusion reactions can spontaneously hemorrhage in the postoperative period.

7) Hypertension is an enemy of the cardiac surgeon. Frequently, patients who are not bleeding develop an episode of significant hypertension and start bleeding via the mediastinal tubes. It is obvious that clots have been forced off injured vessels or hemorrhage has been produced through suture lines due to the increased systolic blood pressure.

The medical therapy to control postoperative hemorrhage should be directed toward the specific problem.

If a coagulopathy is suspected one should obtain a PT and PTT function tests on and to evaluate the clotting cascade of both the intrinsic and extrinsic system. If this is a problem, fresh frozen plasma should be given to correct the clotting defect.

If platelet function is felt to be the problem, one should first obtain a platelet count. If this is low, infusion of 10 units of platelet concentrate should be given. If, however, the platelet count is normal, but one suspects platelet function disorder (e.g. from preop aspirin use), then platelet concentrate should also be given. It is difficult, if not impossible, to obtain platelet function tests on an urgent basis.

Heparin rebound may be the problem. This occurs because of three basic problems:

1) Heparin is bound to fatty tissues which later release it after protamine reversal.

2) The heparin protamine complex is unstable with the half life of protamine being significantly less than heparin, therefore allowing heparin to once again circulate free in the blood stream.

3) Peripheral tissues which have been isolated from the main flow of blood due to vasoconstriction secondary to hypothermia may later become perfused releasing the heparin which is sequestered there.

Irrespective of the cause of hemorrhage, one may evaluate it by performing an activated clotting time (ACT). If the test is positive, heparin rebound situation may be treated with IV boluses of 50 mg of protamine until the ACT is corrected.

Fibrinolysis may be suspected in patients who have had prolonged cardiopulmonary bypass. When one suspects this situation, a serum fibrinogen level may be obtained. In addition, blood drawn from the patient and allowed to clot will show, if followed for a long enough period of time, dissolution of the clot. Under these circumstances, the treatment of primary fibrinolysis is IV administration of Amicar. This drug is given as 5 grams IV push followed by 1 gram per hour until the bleeding stops.

Under circumstances where prolonged episodes of bleeding and clotting have occurred, depletion of the primary source of serum fibrinogen occurs. Under these circumstances, the serum fibrinogen level will be extremely low and the treatment is IV infusion of 10 units of cryoprecipitate. Note: cryoprecipitate is the product of specially prepared serum which is used to treat Hemophilia A. Though the concentrations of Factor VIII are high in this product, the concentration of fibrinogen are also high and approximately 15 times that of fresh frozen plasma.

Disseminated intravascular coagulopathy may occur under various conditions such as sepsis. When this condition is suspected, serum fibrinogen level will be low. The fibrin degradation products will be high, the protamine sulphate test will be positive and the patient's platelet count will be low. The therapy is the IV infusion of heparin to stop the ongoing intravascular coagulation process. However, in the postoperative cardiac patient, this procedure may not be safe.

Indications for Reoperation

The indications for reoperation are dependent upon the mediastinal chest tube drainage. We hold as our criteria three absolute indications:

1) Mediastinal chest tube output of between 300-500 cc per hour for the first hour

2) 200-300 cc per hour for the second hour

3) Greater than 100 cc per hour for 6-8 hours

Though the absolute indications for reoperation are listed above, the treatment each patient must be individualized. Consideration must be given to the operative procedure that the individual patient has undergone. Individuals who have had prolonged complicated operations which may or may not have involved reoperation, where at the end of the case significant effort has been put forth to control bleeding, yet the patient is still bleeding in the postoperative course, should be given a much longer period of time with higher volumes of mediastinal output before returning to the operating room. Frequently, these individuals can be brought under control with intense medical management.

Evaluation of the chest radiograph and hemodynamics play a significant role in determining reoperation. Individuals who may have been bleeding and then suddenly stop, while their chest radiograph shows a widening of the mediastinum with CVP and pulmonary diastolic pressures showing significant equalization and elevation, suggest cardiac tamponade. Under these circumstances, an urgent trip to the operating room for mediastinal evacuation and control of hemorrhage is mandatory.

The absolute trend in bleeding also has a significant part to play. Patients bleeding dramatically who then seem to slow over a period of time may be given more time to see if medical management can effectively control the bleeding.

Preparation for Reoperation

The junior resident should have instructions either from the chief resident or the attending staff to take the patient back to the operating room. The on-call resident should ensure that a slip has been turned in to the operating room so that they know the patient is coming. The patient's family should be informed that the patient is being returned to surgery and an informed consent should be obtained if possible. The house officer should notify all outside attending staff including the patient's private cardiologist that the return is occurring. The resident on call should alert the anesthesia department and again check with the operating room to see that they will be ready. The resident on call should be sure that adequate blood and blood products are available.

Suggested Reading

1. Baumgartner WA, Owens SG, Cameron DE et al eds. The Johns Hopkins Manual of Cardiac Surgical Care. St. Louis: Mosby Year Book, Inc., 1994.

2. Blitt CD. Monitoring in Anesthesia and Critical Care Medicine. New York: Churchill Livingstone, 1985.

3. Kotler MN, Alfieri AD eds. Cardiac and Noncardiac Complications of Open Heart Surgery: Prevention, Diagnosis, and Treatment. Mount Kisco, NY: Futura, 1992.

4. Daily EK, Schroeder JS. Techniques in Bedside Monitoring. St. Louis: Mosby, 1989.

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