Amniotic Fluid Embolus And Cell Saver

[jetproppilot]

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Gotta call yesterday from one of our OBs who had a lady coming for elective C section who survived an amniotic fluid embolus 1.5 years ago...pt required 54 units of blood and other blood products...

OB MD wants the cell saver "just in case"....has a high risk OB coming to help who "has a cuppla papers" on the save utilization of a cell saver in these scenerios, should the pt have another embolus-induced DIC episode.

Would you use a cell saver for this case??


I'm missing the bigger picture here. I suppose I don't know enough about the cell saver especially in regards to OB cases. Is there a hx of the filter missing amniotic deposits?

 

[UTSouthwestern]

Probably not. If the patient is truly exsanguinating, are you going to wait for the cell saver to wash the blood before reinfusing the blood? Doubtful. As the following paper demonstrates, washing the blood with leukocyte depletion filters is paramount to reducing the contaminants in the aspirated fluid and this can still take several precious minutes. You can have it available for backup and use it if the blood loss is tremendous, but at least in the short term, it will not spare the patient of receiving another transfusion of allogeneic blood products.

Waters JH, Biscotti C, Potter PS, Phillipson E. Amniotic fluid removal during cell salvage in the cesarean section patient.
BACKGROUND: Cell salvage has been used in obstetrics to a limited degree because of a fear of amniotic fluid embolism. In this study, cell salvage was combined with blood filtration using a leukocyte depletion filter. A comparison of this washed, filtered product was then made with maternal central venous blood. METHODS: The squamous cell concentration, lamellar body count, quantitative bacterial colonization, potassium level, and fetal hemoglobin concentration were measured in four sequential blood samples collected from 15 women undergoing elective cesarean section. The blood samples collected included (1) unwashed blood from the surgical field (prewash), (2) washed blood (postwash), (3) washed and filtered blood (postfiltration), and (4) maternal central venous blood drawn from a femoral catheter at the time of placental separation. RESULTS: Significant reductions in the following parameters were seen when the postfiltration samples were compared to the prewash samples (median [25th-75th percentile]): squamous cell concentration (0.0 [0.0-0.1 counts/high-powered field (HPF)] vs. 8.3 counts/HPF [4. 0-10.5 counts/HPF], P < 0.05); bacterial contamination (0.1 [0.0-0. 2] vs. 3.0 [0.6-7.7] colony-forming units (CFU)/ml, P < 0.01); and lamellar body concentration (0.0 [0.0-1.0] vs. 22.0 [18.5-29.5] thousands/microl, P < 0.01). No significant differences existed between the postfiltration and maternal samples for each of these parameters. Fetal hemoglobin was in higher concentrations in the postfiltration sample when compared with maternal blood (1.9 [1.1-2. 5] vs. 0.5% [0.3-0.7] ). Potassium levels were significantly less in the postfiltration sample when compared with maternal (1.4 [1.0-1.5] vs. 3.8 mEq/l [3.7-4.0]). CONCLUSIONS: Leukocyte depletion filtering of cell-salvaged blood obtained from cesarean section significantly reduces particulate contaminants to a concentration equivalent to maternal venous blood.

Another issue to consider:Clearance of Fetal Products and Subsequent Immunoreactivity of Blood Salvaged at Cesarean Delivery.
Fong J, Gurewitsch ED, Kump L, et al (Cornell Univ, New York)
Obstet Gynecol 93:968-972, 1999

The findings were that fetal debris was found in blood salvaged 4 minutes after the placenta was removed. Although humoral material is cleared, fetal blood cells are still present in all postprocess salvaged blood. On cross-matching, the product was compatible with maternal blood. Its supernate did not immunoreact with maternal serum.

Editorial comment : In instances of severe intraoperative hemorrhage during pregnancy, the use of salvaged blood employing a cell saver system is often suggested the risk of embolization from particulate matter in salvaged blood and isosensitization from the infusion of incompatible fetal erythrocytes.

Fetal hemoglobin containing red cells from 0.2% to 1.0% is found in salvaged blood. Where the potential for maternal Rh sensitization exists, the authors recommend that samples of saved cells be submitted for Rhogam dose determination. Salvaged blood cross matched with maternal blood and failed to demonstrate antigen antibody precipitate complexes. This to be also provides a strong basis for informed consent in association with the use of the cell saver when such blood is use for autotransfusion.

 

[Disse]

With the high mortality of AFE does anyone truly know the incidence of repeat AFE (last I read no one was entirely sure what causes AFE)? Does previous AFE predispose someone to repeat AFE?

I would think the question to ask would be "is this patient at a high-risk of severe hemorrhage necessitating transfusion?" and/or "does this patient have another risk factor that may add to her needing bolod (severe anemia preop, blah blah blah). Repeat c-sects do have an increased risk of severe bleeding but we still rarely routinely transfuse them.

So, if it was me, I'd say if the patient was otherwise healthy I'd probably say it was unnecessary.

Interesting case

(oh, forgot to add, is the ob bloodletter or not? that could possibly sway the answer 😛 )

 

[militarymd]

Nothing wrong with having the cell saver available. You can always decide on whether you want to use the blood later or not.

I have never thought of cell saver as a device used in the care of patients with massive hemorrhage/exsanguination....I think of it as a device to limit use of allogeneic blood.

In light of extreme safety of today's banked blood, I find it hard to justify using cell saver blood where risk of amniotic fluid contamination exists.

Anyways, there is inadequate data to adequately compare safety of one approach over another....so do what you're comfortable with is what I say.

 

[jetproppilot]

Probably not. If the patient is truly exsanguinating, are you going to wait for the cell saver to wash the blood before reinfusing the blood? Doubtful. As the following paper demonstrates, washing the blood with leukocyte depletion filters is paramount to reducing the contaminants in the aspirated fluid and this can still take several precious minutes. You can have it available for backup and use it if the blood loss is tremendous, but at least in the short term, it will not spare the patient of receiving another transfusion of allogeneic blood products.

Waters JH, Biscotti C, Potter PS, Phillipson E. Amniotic fluid removal during cell salvage in the cesarean section patient.
BACKGROUND: Cell salvage has been used in obstetrics to a limited degree because of a fear of amniotic fluid embolism. In this study, cell salvage was combined with blood filtration using a leukocyte depletion filter. A comparison of this washed, filtered product was then made with maternal central venous blood. METHODS: The squamous cell concentration, lamellar body count, quantitative bacterial colonization, potassium level, and fetal hemoglobin concentration were measured in four sequential blood samples collected from 15 women undergoing elective cesarean section. The blood samples collected included (1) unwashed blood from the surgical field (prewash), (2) washed blood (postwash), (3) washed and filtered blood (postfiltration), and (4) maternal central venous blood drawn from a femoral catheter at the time of placental separation. RESULTS: Significant reductions in the following parameters were seen when the postfiltration samples were compared to the prewash samples (median [25th-75th percentile]): squamous cell concentration (0.0 [0.0-0.1 counts/high-powered field (HPF)] vs. 8.3 counts/HPF [4. 0-10.5 counts/HPF], P < 0.05); bacterial contamination (0.1 [0.0-0. 2] vs. 3.0 [0.6-7.7] colony-forming units (CFU)/ml, P < 0.01); and lamellar body concentration (0.0 [0.0-1.0] vs. 22.0 [18.5-29.5] thousands/microl, P < 0.01). No significant differences existed between the postfiltration and maternal samples for each of these parameters. Fetal hemoglobin was in higher concentrations in the postfiltration sample when compared with maternal blood (1.9 [1.1-2. 5] vs. 0.5% [0.3-0.7] ). Potassium levels were significantly less in the postfiltration sample when compared with maternal (1.4 [1.0-1.5] vs. 3.8 mEq/l [3.7-4.0]). CONCLUSIONS: Leukocyte depletion filtering of cell-salvaged blood obtained from cesarean section significantly reduces particulate contaminants to a concentration equivalent to maternal venous blood.

Another issue to consider:Clearance of Fetal Products and Subsequent Immunoreactivity of Blood Salvaged at Cesarean Delivery.
Fong J, Gurewitsch ED, Kump L, et al (Cornell Univ, New York)
Obstet Gynecol 93:968-972, 1999

The findings were that fetal debris was found in blood salvaged 4 minutes after the placenta was removed. Although humoral material is cleared, fetal blood cells are still present in all postprocess salvaged blood. On cross-matching, the product was compatible with maternal blood. Its supernate did not immunoreact with maternal serum.

Editorial comment : In instances of severe intraoperative hemorrhage during pregnancy, the use of salvaged blood employing a cell saver system is often suggested the risk of embolization from particulate matter in salvaged blood and isosensitization from the infusion of incompatible fetal erythrocytes.

Fetal hemoglobin containing red cells from 0.2% to 1.0% is found in salvaged blood. Where the potential for maternal Rh sensitization exists, the authors recommend that samples of saved cells be submitted for Rhogam dose determination. Salvaged blood cross matched with maternal blood and failed to demonstrate antigen antibody precipitate complexes. This to be also provides a strong basis for informed consent in association with the use of the cell saver when such blood is use for autotransfusion.

Thanks for the posts, and thanks UT, for putting the papers on here.

Case was done yesterday without incident..the cell saver was in the room but we had no intent of using it even in the event of emergency. I agree that with the relative safety of banked blood products it would be hard to justify using the cell saver and its inherent risks, even in light of a couple of papers testifying to the "safety" of this technique in OB.

Until there is more data (more papers, more widespread use of this technique) I'll choose the conventional approach of using blood bank products rather than risk DIC ignition from intravascular introduction of proinflammatory substances from a cell saver.

Things that appear safe initially sometimes come back to bite you...i.e. cox-2s, rapacuronium, etc

I don't think there is enough data to say one way or the other whether a history of AFE predisposes to another one, since most of them die first time around.