Learn from Harold Wu, M.D., minimally invasive gynecologic surgeon, on the latest advances of cell salvage technology as well as the benefits, risks and contraindications for us of cell salvage in the context of benign gynecologic surgery.
I'm Harold wu one of the middle invasive gynecologic surgeons here at Hopkins and I'd like to take some time with you today to discuss self salvaged technology in benign gynecologic surgery, I have no financial disclosures. So today, as a brief objective or outline, we'll take a look at cell salvage technology and discuss its benefits, risks and contraindications for use and also examine cell saver use in the context of benign gynecologic surgery. To start a definition, cell salvages re infusion of the patient's own blood loss during surgery. Also known as auto transfusion or inter operative autologous transfusion. I think this topic is quite important because cell salvage has notable benefits with high clinical utility in several clinical settings. It's also important to any specialty, including gynecologic surgery that involves high volume blood loss procedures with increased risk for needing blood transfusions. There's also potential for increased utilization across various practice patterns. So how does it work? We'll sell selfish starts with aspiration of blood from the operative field which is then mixed with a hyper analyzed anticoagulants, saline and stored in a filtered reservoir once the surgery is over. Or there's enough blood that's ready for re infusion processing stage begins where the red blood cells are concentrated and separated in a centrifuge bowl through centrifuge ation and then washed with isotonic fluid such as normal ceiling and that removes any free hemoglobin or cellular debris that can be thermal genic. Once the processing stages complete the blood is then transferred to a re infusion bag. And before it actually is re infused into the patient. It's further purified with standard micro aggregate filters or even specialized leukocyte depletion filters that allow ultimate removal of leukocyte bacteria or even cancer cells and amniotic fluid. If the blood isn't used right away, the salvage blood can be stored Um at room temperature up to six hours or up to 24 hours at 1-6°C. The efficiency for self selfish technology is typically around 60% plus or minus 20 of the shed blood recovered and and efficiency can be increased by squeezing out the surgical sponges that are saturated and also salvaging that blood as well. The threshold for blood loss for processing a re infusion is typically about 300-500 ccs depending on the size of the Centrifuge Bowl. And there are several benefits to note for cell saber use. Um One of the main ones is that allows for the avoidance and reduction in allergenic blood transfusions with the reduction of the attendant costs and risks such as transfusion reactions or transmitted infections. The strongest evidence overall in major vascular cardiac and complex orthopedic surgery. So for example there was a large 2010 Cochrane review that had 75 R. C. T. S. Primarily an Ortho cardiac and vascular surgery cases That found about a 40% reduction in proportion of patients exposed to allow genetic transfusions with cell saver use. And that's an average saving of about .7 units packed red blood cells per patient. And then a more recent Cochrane review in 2015, they tried to focus on trauma. So really only one RCT met criteria but nevertheless they found that cell salvage reduced eliminated transfusions by about five units within the 1st 24 hours in these patients. So another major benefit for cell salvage use is that there can be improved of let's sell quality um with decreased storage lesions 23 D. P. G. Is assault that is found in red blood cells that plays a role in offloading oxygen from hemoglobin in the peripheral circulation. And studies have shown that there is pretty much normal levels similar to fresh blood in salvage red cells. However, in bank red cells there's a dose dependent depletion based on how long that those red blood cells are stored. Red cell memory deform ability. It is also pretty much the same in red blood cells that are salvaged. However, there's a dose dependent loss of dependability in bank red blood cells as well. There have been concerns in the past for residual heparin within salvage red blood cell bags. However, studies have shown that the hyper concentration is so minimal as it is to be clinically irrelevant. And then you can also see that the average hematocrit is comparable in salvage red blood cells versus bank red blood cells and of course one of the biggest benefits for self salvage uses that we can optimize care for patients who do not accept Iowa genetic blood transfusions, whether it's for personal reasons or religious beliefs like Jehovah's witnesses And studies have shown that greater than 95% of Jehovah's witness patients will accept salvage blood with appropriate counseling. Some of the possible requests that they might make include that the blood does not leave the operating room or that the cell saver tubing and equipment remain connected to their I. V. Catheters to maintain continuity with their circulation. And all of this can be easily set up with the equipment in the room. There are some potential complications to note um their overall similar to transfusion of allergenic blood itself. For example, Delusional kogelo apathy or transfusion associated circulatory overload infection is still quite rare. Air embolism can occur where active devices pump air into the re infusion bag. But actually this is pretty much preventable because the blood is transferred into a separate bag and disconnected from any cell favored device that can actually pump air before it's re infused into the patient. And then fat micro aggregate embolism is also a theoretical possibility but it's really largely preventable by washing and with use of those filters that we talked about before. In fact, a multi center retrospective review of Cell saver safety in 2016 with over 33,000 patients noted only to adverse events, none of which we're air emboli or deaths from cell salvage use. There are some contraindications to keep in mind. However, one should not use hipAA tonic solutions such as sterile water because that will list all the red blood cells that you worked hard to salvage. Um Any toxic substances with ivy administration like antibiotic irrigation, hydrogen peroxide or iodine should be avoided as well. And then admixture with certain products need to be avoided like topical thrombin or phi brain or bone cement. In fact if topical thrombin and fiber and um substances are accidentally re infused into the patient and actually lead to de. I see. So that's definitely something we want to avoid. And then we'll switch gears a little bit to take a look at cell salvage juice and benign G Y N a million invasive surgery. We'll be focusing primarily on my meta means because that's a procedure that has a high potential for large volume blood loss especially with complex pathologies and complex fibroid burden. Overall there have been few studies there primarily small and observational reporting on the use of cell saver during myomectomy ease and they pretty much commented on its overall safety and increase in hematology parameters such as post dot hemoglobin. There was a large retrospective study in 2014 looking at cell salvage use and open my magazines. They involved about 600 patients And about 70% of those had cell saver equipment set up in the room and about 1/5 of those patients or 85 patients ultimately re infused, sell salvage use was at the discretion of the surgeon in the study. Re infusion was associated with uterine size greater than 15 weeks longer operative time and larger estimated blood loss greater than a leader. About 10% of patients with cell salvage setup required additional allergenic blood transfusions anyway. But they were able to save about 144 units for patients. There's overall lack of data or guidelines regarding cell saver use and middle invasive myomectomy. He's so we decided to take a look at our own institutional experience here at the johns Hopkins Hospital and we did a retrospective study Of cell salvage youse and mes. Myomectomy is over the course of three years and in our cohort we had about 382 patients And about 20% of those patients had cell saver setup and half of those cases or 30 patients ultimately got re infused. And again sell salvage setup was of course at the surgeon's discretion because of the lack of guidelines are strict um rules for use But we were able to save about 9.5 L of blood and salvage 32 units of packed red blood cells. In looking at those patients and the subgroups of our cohorts. The patients who ultimately were re infused had larger fibroid size, bigger uterine size, higher specimen weight and also a greater E. B. L and operative time. Similar to some of the findings from prior studies but there are some important implications or considerations to take into account with increased adoption of miES and multimodal blood management programs, there's actually reduced overall need for allergenic transfusions anyway, so the appropriate selection of cases for cost effective cell salvage uses all the more important so that we don't waste resources setting up equipment that we ultimately don't need And just to give a brief context or background into costs. One unit of allergenic packed red blood cells is about $200. Um And that's the acquisition from the red cross. But if you include all the steps such as blood donation processing and transport, that cost can be fourfold higher up to $800 from prior studies, self selfish device. Once it's been The machine or the equipment has been purchased is about $50 for set up equipment only. And then the additional resources for re infusion goes up to about $120. Of course that's institutionally dependent. So you should check with your own institution about those costs but that's a good rough estimate. So there are no standard guidelines for cell saver use, as I mentioned earlier, a lot of it is up to surgeon preference at the moment and that introduces a lot of selection bias into retrospective study outcomes. Nevertheless, maximum fibroids and uterine size based on pre op exam or imaging could be helpful indicators to optimize care in this setting. So looking to the future. Um I think we really need perspective studies to clarify preoperative predictors for self saver use and that helps us establish guidelines to optimize patient outcomes and cost conscious care. In the meantime, I think one can still consider cell salvage use for procedures with significant or complex pathology with increased risk for high volume blood loss, for example, complex myomectomy or specific patient populations who do not accept allergenic transfusions. These are my references. Thank you so much for your time and attention and please feel free to reach out with any questions or comments or if you'd like to talk further about the subject.