Residual heparin concentrations in salvaged blood from the Sorin Xtra® autotransfusion system during cardiac surgery
| dc.contributor.advisor | Levin, Andre Ian | en_ZA |
| dc.contributor.advisor | Buys, Willem Frederik | en_ZA |
| dc.contributor.author | Buys, Mathilde | en_ZA |
| dc.contributor.other | Stellenbosch University. Faculty of Health Sciences. Dept. of Anaesthesiology and Critical Care. | en_ZA |
| dc.date.accessioned | 2016-12-22T13:30:51Z | |
| dc.date.available | 2016-12-22T13:30:51Z | |
| dc.date.issued | 2016-12 | |
| dc.description | Thesis (MMed)--Stellenbosch University, 2016. | en_ZA |
| dc.description.abstract | Introduction: Cell salvaging is a fundamental component of blood conservation during cardiac surgery. It entails intra-operative scavenging, washing and collection of a patient’s blood for retransfusion at completion of surgery. During surgery vast amounts of heparin is administered to avoid fatal thrombosis in both the bypass and autotransfusion circuits. Adequate heparin removal during the cell salvaging process is thus crucial to avoid retransfusion of heparin to these high risk patients. We wanted to measure heparin levels in the collected reinfusate prior to retransfusion, in order to quantify heparin removal in our current autotransfusion system, the Sorin Xtra®. Method This study was subjected to ethical committee approval prior to initiation (S14/03/050). 31 adult patients undergoing on pump cardiac surgery in Tygerberg Academic Hospital were recruited after taking informed consent. A standard cell salvaging process was used for setup using the Sorin Xtra® autotransfusion system. After completion of the cell salvaging process, a blood sample was aspirated from the collected reinfusate and stored in a standard citrated blood sampling tube. Sample processing and heparin measurement were performed in the haematology laboratory of Tygerberg Hospital. A modified anti-Xa heparin assay was employed to measure reinfusate heparin levels, since the absence of coagulation factors necessitates the addition of a set amount of normal pooled plasma prior to performing the assay. Results The mean heparin levels measured in the Sorin Xtra® reinfusate were 0.52 (IQR 0.16 – 0.74; 95% CI 0.30 – 0.66) IU/ml. The 95% confidence intervals did not encroach on the alternative hypothesis, but did span the value representing the null hypothesis. The data thus failed to reject the null hypothesis, indicating clinically significant reinfusate heparin levels. Sixteen of 31 reinfusates (56%; 95% confidence interval 35 to 68%) exhibited heparin concentrations exceeding 0.5 IU/ml. There was no clinically significant relationship (r2 0.02, p = 0.46) between heparin dosage administered to the patient and the concentration measured in the reinfusate. Conclusion Clinically significant heparin levels in cell saving reinfusate can potentially worsen postoperative bleeding in cardiac surgery. The mean heparin level measured in our study was more than the AABB’s recommended value of 0.5IU/ml, and 16 samples had absolute values more than this. Although the absolute heparin dose retransfused remain debatably low, the possibility of heparin induced coagulopathy should be entertained in cardiac patients that received reinfusate from the Sorin Xtra® ATS with ongoing postoperative bleeding in our institution. A practical suggestion in these cases would be to quantify heparin activity either with a point of care device (TEG/ROTEM) or direct measurement of heparin concentration using an Anti-Xa assay and titrating heparin reversal accordingly. | en_ZA |
| dc.description.abstract | Inleiding: Eritrosiet-suiweringstoestelle speel ‘n belangrike rol in bloed besparing tydens opehart chirurgie. Dit behels die versameling, was en prosessering van ‘n pasïent se eie bloed gedurende chirurgie, met die doel om die geprosesseerde bloed op ‘n latere stadium terug te transfuseer. Tydens opehart chirurgie word heparien gebruik om stolling in die omleiding- en bloedbesparingsisteme te voorkom, aangesien blootstelling aan die negatiewe oppervlakte van díe sisteme wydverspreide bloedstolling aktiveer. Heparien verwydering gedurende bloedsuiwering is dus noodsaaklik om die hertransfusie daarvan te beperk, omdat betekenisvolle heparienvlakke ‘n koagulopatie kan teweegbring in die onmiddelike postoperatiewe periode wanneer stolling van uiterste belang is. Heparien suiwering in die betrokke toestelle wat in ons instansie gebruik word is nog nie voldoende nagevors nie. Met hierdie studie het ons dus gepoog om die heparien vlakke in geprosesseerde bloed van ons huidige selsuiweringstoestel, die Sorin Xtra®, te bepaal. Metode Die studie is uitgevoer in Tygerberg Akademiese Hospitaal na goedkeuring van die etiese komitee(S14/03/050). 31 volwasse pasïente wat opehart chirurgie ondergaan het is gewerf na ingeligte toestemming verkry is. Slegs gevalle wat kardiopulmonale omleiding benodig het en waarvoor die Sorin Xtra® toestel gebruik is, is genader. Die bloedsuiwerings opstelling was gestandardiseer. ‘n Bloedmonster is geneem vanuit die geprosesseerde bloed na voltooiing van die suiweringsproses en in ‘n standard sitraatbuis geplaas. Die monsters is geneem na Tygerberg Hospitaal se hematologie en stollingslaboratorium vir prosessering en meting van heparienvlakke. Om die monsters se heparien vlakke akkuraat te meet is ‘n gemodifiseerde anti-Xa toets gebruik. Die afwesigheid van stolfaktore en ATIII in die geprosesseerde bloedmonsters vereis die toevoeging van normale gepoelde plasma voor die toets uitgevoer kan word. Resultaat Gemiddelde heparien vlakke van 0.52 (IQR 0.16 – 0.74; 95% CI 0.30 – 0.66) IU/ml is gemeet in die geprosesseerde bloed van die Sorin Xtra® toestel. Die 95% sekerheidsinterval het nie die alternatiewe hipotese se waarde ingesluit nie, maar wel die nul hipotese. Die data het nie die nul hipotese verwerp nie, wat aandui dat die gemiddelde heparien vlakke wat gemeet is wel statisties noemenswaardig is. 16 van die 31 monsters (56%; 95% sekerheidsinterval 35 to 68%) het heparien vlakke gehad van meer as 0.5IU/ml. Daar is geen kliniese verwantskap (r2 0.02, p = 0.46) tussen die gemete heparien vlakke en die hoeveelheid heparien wat toegedien is nie. Samevatting Noemenswaardige heparienvlakke in geprosesseerde bloed van selbesparingstoestelle kan post operatiewe bloeding vererger na opehart chirurgie. Die gemiddelde heparien vlak in geprosesseerde bloed van die Sorin Xtra® selbesparingstoestel is meer as die AABB se voorgestelde waarde van 0.5IU/ml. Sestien van die 31 monsters het hoër vlakke gehad as die voorgestelde waarde van 0.5IU/ml. Alhoewel die absolute dosis heparien wat teruggegee word debateerbaar min is, moet heparien geinduseerde koagulopatie steeds uitgeskakel word as ‘n moontlike oorsaak van bloeding in hierdie groep pasïente wat geprosesseerde bloed van die Sorin Xtra® toestel ontvang het. Heparien aktiwiteit kan gekwantifiseer word met behulp van tromboelastografie (TEG/ROTEM) of direkte heparien vlak bepaling deur middel van ‘n anti-Xa toets om sodoende heparien omkering te lei. | af_ZA |
| dc.format.extent | 53 pages | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/10019.1/100241 | |
| dc.language.iso | en_ZA | en_ZA |
| dc.publisher | Stellenbosch : Stellenbosch University | en_ZA |
| dc.rights.holder | Stellenbosch University | en_ZA |
| dc.subject | Autotransfusion system, cardiac surgery, Cell salvaging, blood conservation, Blood transfusion | en_ZA |
| dc.subject | Blood -- Transfusion, Autologous | en_ZA |
| dc.subject | Cardiac surgery | en_ZA |
| dc.subject | Heparin | en_ZA |
| dc.subject | UCTD | en_ZA |
| dc.title | Residual heparin concentrations in salvaged blood from the Sorin Xtra® autotransfusion system during cardiac surgery | en_ZA |
| dc.type | Thesis | en_ZA |