July 2010, Vol. 2, Issue 6

A Washed Cell is a Happy Cell

Submitted by: Timothy Hannon, MD, MBA | Founder & President,
Strategic Healthcare Group, LLC

I recall fondly a button that my early blood management mentor, Dr. Paul Potter, used to wear on his lab coat with that particular saying.  Dr. Potter was a staff anesthesiologist at the Naval Medical Center San Diego, and he was an early proponent of all things blood management, especially autotransfusion (commonly referred to as “cell saver” or “cell salvage”).  Dr. Potter was introduced to early versions of autotransfusion machines as a young Navy Corpsman during the Vietnam era.  The Navy- Marine Corps team has always worked in austere environments, and the ability to retransfuse shed blood in a combat setting was a tremendous advance.  Many combat ships and most forward medical aid stations did not have the ability to store blood products, so autotransfusion greatly enhanced the capabilities of the “walking blood bank.”   Dr. Potter taught a generation of Navy anesthesiologists, including myself and Dr. Jonathan Waters, the benefits of autotransfusion as a tool in the blood management tool box.  It is interesting to note that another Naval Medical Center San Diego alumnus, Dr. Carlos Brown from University Medical Center Brackenridge, just published a case series noting the safety and cost effectiveness of autotransfusion in trauma patients.¹

 Although the first generation of autotransfusion machines had a number of safety and quality issues, modern autotransfusion machines operated by trained individuals are a safe, efficient and cost effective way to reduce the need for banked allogeneic blood.  These machines wash out 90- 95% of supernatant contaminants and debris, and return a high percentage of shed blood with good technique.  A distinct advantage of autotransfusion blood is that it is fresh and autologous, a tremendous bonus as we increasingly ponder the risks of allogeneic blood and the “storage lesion.”  The general indications for autotransfusion include an anticipated blood loss of 20% or more of the patient’s estimated blood volume;  when blood would ordinarily be crossmatched;  when more than 10% of patients undergoing the procedure require transfusion;  or when the mean transfusion for the procedure exceeds one unit.   In my experience, autotransfusion is an overlooked and underutilized strategy in most hospitals across the nation.  A prime reason is an underestimation of the relative risks and costs of allogeneic blood products, leading to poor risk-benefit and cost-benefit comparisons between banked blood and autotransfusion.  Other reasons include a lack of availability of the technology in some hospitals, and misperceptions about absolute vs. relative contraindications for autotransfusion.

Autotransfusion has been traditionally used in cardiac, vascular and orthopedic surgery, and its use has been contraindicated in contaminated intra-abdominal surgery, obstetrics and cancer surgery.  Several studies in the last decade have moved these types of surgeries from absolute contraindications to relative contraindications.  Studies such as Dr. Brown’s case series have shown autotransfusion to be safe and potentially lifesaving in trauma patients, and Dr. Waters has spent years proving that autotransfusion can also be safe in obstetric hemorrhage.² Obstetric hemorrhage is the leading cause of maternal death during childbirth, so adding autotransfusion as an option in severe hemorrhage is a recommended component of an OB hemorrhage response team.  Autotransfusion has also been shown to be safe in some cancer surgeries, such as radical retropubic prostatectomy.³ Although autotransfusion machines are ineffective in washing out all cancer cells, it has been noted that these patients already have circulating cancer cells at the time of operation and that returned cells may be incapable of metastasizing.  Further, using the patient’s own blood can potentially avoid the immunosuppressive effects of allogeneic blood.  Not all cancer surgeries are amenable to autotransfusion, and Dr. Waters recommends the use of a leukoreduction filter to further reduce cancer cells from the washed, shed blood.⁴ 

A final point of discussion is that not all autotransfusion is created equal.  Some orthopedic and cardiac surgeons continue to return unwashed wound shed blood to patients postoperatively.  It is my opinion as well as the opinion of other experts that the return of unwashed shed blood is not a sound practice. ⁵ Blood collected from surgical wounds typically has a low hematocrit and is usually of poor quality from surgical debris and harmful inflammatory mediators.  Common complications associated with retransfusion of unwashed shed blood include systemic inflammatory response (SIRS), TRALI, and increased postoperative bleeding as a result of fibrin degradation-induced disseminated intravascular coagulopathy (DIC).  Simple filtration systems are insufficient to remove cytokines and fibrin degeneration products, so I feel there is no “safe” amount of this blood that can be returned.  If shed blood is of sufficient quantity to be retransfused, it should be washed on a certified autotransfusion device that is operated by qualified personnel.  To further complicate the situation, there is concern that the surgical drains themselves may contribute to an increased blood loss in orthopedic surgery.  A review of the use of drains in the Journal of Bone and Joint Surgery concluded that the use of drains in primary hip and knee surgery did not decrease complication rates compared to not using drains, but did result in more blood transfusions.⁶ This probably relates to continued “weeping” from cut bone surfaces that is encouraged by drains, as opposed to tamponade with no drain and a pressure dressing.  Therefore, there seems to be no role for autotransfusion in unilateral primary hip and knee surgery since the use of drains seems obviated.⁷

Selected References:

¹ Brown CVR, Foulkrod KH, Salder HT, et al. Autologous blood transfusion during emergency trauma operations.  Arch Surg 2010;145(7):690-94.

² Water JH, Biscotti C, Potter PS, et al. Amniotic fluid removal during cell salvage in the cesarean section patient.  Anesthesiology 2000; 92:1531–36.

³ Gray CL,  Amling CL, Polston GR, et al. Intraoperative cell salvage in radical retropubic prostatectomy. Urology 2001;58:740-45.

⁴ Waters JH.  Indications and contraindications of cell salvage. Transfusion 2004;44:40S-44S.

⁵ Hansen E, Pawlik M. Reasons against the retransfusion of unwashed wound blood.  Transfusion 2004;44:45S-53S.

⁶ Parker MJ, Roberts CP, Hay D. Closed suction drainage for hip and knee arthroplasty: A meta-analysis. J Bone Joint Surg Am 2004:86-A:1146-52.

⁷ Hannon TJ, Pierson JL. Blood management. In: American Academy of Orthopaedic Surgeons Comprehensive Orthopaedic Review, Lieberman JR, editor. AAOS 2009; Rosemont, IL.