The complexities of transfusion reactions: Coexistence of a delayed haemolytic transfusion reaction and post-transfusion purpura

BACKGROUND AND OBJECTIVES

Immune-mediated acute or delayed transfusion reactions occur when there is immunological incompatibility between transfused blood products and recipient's antibodies. Acute haemolytic transfusion reactions occur within 24 h and are delayed after 24 h up to 10 days following transfusion, whereas post-transfusion purpura (PTP) typically occurs 7-10 days post-transfusion. We present a case of a previously transfused and recently post-partum female who developed both delayed haemolytic transfusion reaction (DHTR) and PTP.

CASE REPORT

A 42-year-old woman, G2P1, with non-alcoholic liver disease, portal hypertension and previous transfusion history with allogeneic anti-E, developed a severe DHTR and PTP following a complicated post-partum course and multiple transfusions. The antenatal and initial post-partum pre-transfusion antibody screens were negative. Subsequently five red cell antibodies, including anti-c, anti-Fya, anti-Jkb and anti-S and the reappearance of anti-E were, however, identified during follow-up investigations along with the anti-platelet antibody HPA-3a and human leukocyte antigen class I antibodies. Anti-E, anti-Jkb and anti-S were eluted from the circulating red blood cells.

CONCLUSION

To our knowledge, there have been only two other case reports of DHTR and PTP occurring in the same patient.

Challenges in antibody titration for ABO-incompatible renal transplantation

BACKGROUND AND OBJECTIVES

Accurate and regular monitoring of anti-A and anti-B titres pre- and post-transplantation plays a crucial role in the clinical management of patients receiving ABO-incompatible renal transplants. There is no standardized protocol or an external quality assurance program (EQA) currently available for this testing in Australia. The aim of this study was to investigate the diversity of techniques, test platforms and reagents that were currently in use in various laboratories with the aim of developing an EQA.

MATERIALS AND METHODS

An online survey was sent to the participants enrolled with the Royal College of Pathologists of Australasia Quality Assurance Program (RCPAQAP) to assess their interest in participation in the pilot study. A total of 24 participants who expressed interest were sent the group O plasma, A₁ , A₂ and B cells to perform ABO titration using their own methods.

RESULTS

Participants reported a wide range of titre results, from 8 to 1024 for the anti-A titre using A₁ cells, from 2 to 128 for anti-A titre using A₂ cells and from neat to 32 for anti-B titre using B cells.

CONCLUSION

There was a wide variation in titre results between and within different technologies. These findings demonstrate the need for an ABO titration EQA. Development of a standard technique and participation in an EQA program should, over time, reduce variation and enable transferrable results across testing centres, which will assist in consistent clinical interpretation and better outcomes for patients.

Anaemia in elderly patients at discharge from intensive care and hospital

BACKGROUND AND OBJECTIVES

Anaemia is common in the elderly and is recognized as a risk factor for several adverse outcomes in older adults, including hospitalization, morbidity and mortality. The study aims were to examine the prevalence of anaemia in elderly patients at discharge from the intensive care unit (ICU) and hospital.

MATERIALS AND METHODS

Patient randomized under the INFORM trial and with an ICU admission were included. Two cohorts, Cohort 1 patients who were alive on discharge from ICU and Cohort 2 patients who were discharged alive from hospital to home. Prevalence of significant anaemia defined as haemoglobin levels, less than 100 g/l was measured at ICU and hospital discharge.

RESULTS

Overall, 76·5% (683/893) of elderly admissions in Cohort 1 had a haemoglobin <100 g/l, and 44·1% (395/893) had a haemoglobin <90 g/l on ICU discharge. Nadir haemoglobin during ICU stay, length of stay in ICU and transfusion during ICU stay was associated with significant anaemia at ICU discharge. At hospital discharge, in Cohort 2, 54·8% (263/480) of elderly ICU admissions had Hb < 100 g/l, and 23·4% (112/480) had Hb < 90 g/l. Male gender, haemoglobin level at ICU discharge, and length of stay and nadir Hb between ICU and hospital discharge were associated with anaemia at hospital discharge.

CONCLUSIONS

Significant anaemia is highly prevalent in elderly patients on discharge from ICU and to a lesser degree at hospital discharge.

Extending the post-thaw viability of cryoprecipitate

BACKGROUND

Cryoprecipitate has a short post-thaw expiry time of 6 h. The aim of this study was to assess the stability and function of cryoprecipitate components (FVIII, fibrinogen, vWF, and FXIII) and cryoprecipitate sterility up to 120 h post-thawing when stored at two temperatures (2-6°C and room temperature [20-24°C]).

METHODS AND MATERIALS

Twenty batches (110 individual units) of time-expired, thawed cryoprecipitate were collected. Units were sampled at the 6-h expiration mark and then stored at 2-6°C or room temperature (RT). They were resampled every 24 h for 120 h. One unit from each batch was sent for sterility testing at 120 h. Samples had FVIII (one stage and chromogenic), fibrinogen, FXIII, vWFag, and vWF:RCo assays performed in batches. Rotational thromboelastometry (ROTEM) was also performed.

RESULTS

FVIII levels declined significantly at 120 h post-thawing at both RT and 2-6°C, but still met international standards for FVIII content. Fibrinogen, vWF antigen, and FXIII levels reduced minimally over 120 h and always met international standard requirements when stored at either temperature. ROTEM analysis demonstrated that fibrinogen function was not compromised at 120 h post-thawing under both storage conditions. vWF:RCo levels declined significantly over 120 h at both storage temperatures. No bacterial contamination was detected in 20 units of cryoprecipitate following storage for 120 h post-thawing.

CONCLUSION

These results demonstrate that extension of the storage time of thawed cryoprecipitate to 120 h, stored at either 2-6°C or RT, is feasible while still maintaining required FVIII, fibrinogen, and vWFag levels. Storage at 2-6°C has the advantage of reduced risk of potential bacterial contamination.

Warming blood prior to transfusion using latent heat

OBJECTIVE

Major trauma is associated with blood loss and hypothermia. It is common to replace lost fluid with red cells stored at 2-6°C, and/or colloid/crystalloid fluid stored at ambient temperature, thus increasing hypothermia risk. At trauma and medical retrieval sites, mains electricity powered fluid warmers cannot be generally used. Latent heat provides an alternate practical method of portable temperature-controlled intravenous fluid warming. This work investigates the safety and efficacy of a fluid warmer powered by latent heat.

METHODS

Twenty-five haematology patients received red cell transfusions, one through a fluid warmer, using latent heat from a super-cooled liquid and one without warming. Temperature of donor red cell units was measured after passing through fluid warmers. Blood samples were collected from red cell units and patients, prior and after each transfusion. These were tested for haemolysis markers (plasma haemoglobin, potassium, lactate dehydrogenase, bilirubin) and for traces of super-cooled liquid. Patient physiological parameters (oxygen saturation, pulse, temperature, blood pressure, respiration) were monitored during each transfusion.

RESULTS

Patient's physiological signs remained stable and no transfusion reactions were observed during warm transfusions. Latent heat fluid warmers increased the temperature of red cell units to approximately 35°C. There were no significant differences in haemolysis markers following warmed and unwarmed transfusions, and no contamination of red cell units by super-cooled liquid was detected.

CONCLUSION

The latent heat fluid warmer was shown to safely warm transfused blood in a controlled clinical setting.

Vox Sanguinis International Forum on the use of prehospital blood products and pharmaceuticals in the treatment of patients with traumatic haemorrhage

While specific practices and transported blood products vary around the world, most of the respondents in this International Forum transported at least one blood product for the transfusion to bleeding patients en route to the hospital. The most commonly carried product was RBCs, while the use of whole blood will likely increase given the recent reports of its successful use in the civilian setting, and because of the change in the AABB's Standards regulating its use. It will be interesting to see if plasma use in the prehospital setting becomes more widely used given today's enhanced appreciated of the coagulopathy of trauma and plasma's beneficial effect in reversing it, and if blood products are transported to the scene of injury by more vehicles, that is, not just predominantly in helicopters. It was not surprising that TXA is being widely administered as close to the time of injury as possible given its potential benefit in these patients. This International Forum highlights the importance of focusing attention on prehospital transfusion management with a need to further high‐quality research in this area to guide optimal resuscitation strategies.

Red blood cell storage and in-hospital mortality: a secondary analysis of the INFORM randomised controlled trial

BACKGROUND

No randomised trials have addressed whether exposure to red blood cells (RBCs) stored longer than 35 days is associated with harm in patients. We aimed to assess the risk of in-hospital mortality associated with transfusing blood stored longer than 35 days.

METHODS

We did a secondary analysis of the INforming Fresh versus Old Red cell Management (INFORM) trial, a pragmatic, multicentre, randomised controlled trial of patients (≥18 years) admitted to one of six hospitals in Australia, Canada, Israel, and the USA and expected to need RBC transfusions. Patients were randomly assigned (2:1) to receive blood in inventory stored for the longest time (standard care) or the shortest time, using a random allocation schedule and stratified by centre and patient ABO blood group. The primary objective of the INFORM trial was to assess all-cause in-hospital mortality in patients with blood group A and O who were transfused. For our exploratory secondary analysis, we classified individuals into one of three mutually exclusive exposure categories on the basis of the maximum storage duration of any blood unit patients had received on each day in hospital: exclusively exposed to RBCs stored no longer than 7 days, exposed to at least one unit of RBCs stored 8-35 days, and exposed to least one unit of RBCs stored longer than 35 days. Our primary objective was to determine the effect on risk of in-hospital death of time-dependent exposure to RBCs stored longer than 35 days compared with exclusive exposure to RBCs stored no longer than 7 days, both in patients of blood groups A and O and all patients. The INFORM trial is registered as an International Standard Randomised Controlled Trial, number ISRCTN08118744.

FINDINGS

Between April 2, 2012, and Oct 21, 2015, 31 497 patients were recruited, and 24 736 patients were eligible for inclusion in this analysis. We excluded nine patients for whom information about the storage duration of transfused blood was missing and one patient whose sex was unknown. 4480 (18%) patients were exposed to RBCs with longest storage, 1392 (6%) patients were exposed exclusively to RBCs with shortest storage, and 18 854 (76%) patients were exposed to RBCs stored 8-35 days. Median follow-up was 11 days (IQR 6-20). Exposure to RBCs stored longer than 35 days was not associated with increased risk of in-hospital death compared with exclusive exposure to the freshest RBC units after adjusting for demographic variables, diagnosis category, and blood product use history (in patients with blood group A or O: hazard ratio 0·94, 95% CI 0·73-1·20, p=0·60; in all patients: 0·91, 0·72-1·14, p=0·40). The risk of in-hospital death also did not differ between patients exposed to blood stored 8-35 days and patients exposed to blood stored 7 days or less (in patients with blood group A or O: 0·92, 0·74-1·15, p=0·48; in all patients: 0·90, 0·73-1·10, p=0·29).

INTERPRETATION

These data provide evidence that transfusion of blood stored for longer than 35 days has no effect on in-hospital mortality, which suggests that current approaches to blood storage and inventory management are reasonable.

FUNDING

Canadian Institutes for Health Research, Canadian Blood Services, and Health Canada.

Any changes in recent massive transfusion practices in a tertiary level institution?

BACKGROUND & OBJECTIVES

A previous review of transfusion practices in our institution between 1998 and 2008 showed a trend of high ratios of red cells (RC) to plasma (FFP) and platelets to RC towards the later years of review period. The aim of the study was to further evaluate transfusion practices in the form of blood product usage and outcomes following massive transfusion (MT) METHODS: All adult patients with critical bleeding who received a MT (defined as ≥10 units of RC in 24h) in 2008 and between January 2010 and December 2014 were identified. Blood and blood products transfused, in-hospital mortality, 24h and 90-day mortality were analysed for the period 2010-2014. Blood and blood product usage, massive transfusion protocol (MTP) activation and use of ROTEM between 2008 and 2014 were compared.

RESULTS

A total of 190 MT including surgical (52.1%), gastro-intestinal bleeding (25.3%), trauma (11.6%) and obstetric haemorrhage (5.8%) episodes were identified between 2010 and 2014. The overall in-hospital mortality was 26.7% with a significant difference in 24h (p=0.04) and 90-day mortality (p=0.02) between diagnostic groups. Comparing 2008 (n=33) and 2014 (n=23), there was no significant difference in median RC, FFP and platelet units, cryoprecipitate doses and RC:FFP ratio; however there was an increase in number of patients who used cryoprecipitate (54.5% vs 87%, p=0.01).

CONCLUSION

Aligned with haemostatic resuscitation, the trend continues in the form of increased use of plasma and higher RC:FFP transfusion ratios including an increase in number of patients receiving cryoprecipitate.

Mortality outcomes in patients transfused with fresher versus older red blood cells: a meta-analysis

BACKGROUND

Among transfused patients, the effect of the duration of red blood cell storage on mortality remains unclear. This study aims to compare the mortality of patients who were transfused with fresher versus older red blood cells.

METHODS

We performed an updated systematic search in the CENTRAL, MEDLINE, EMBASE and CINAHL databases, from January 2015 to October 2016. RCTs of hospitalized patients of any age comparing transfusion of fresher versus older red blood cells were eligible. We used a random-effects model to calculate pooled risk ratios (RRs) with corresponding 95% confidence interval (CI).

RESULTS

We identified 14 randomized trials that enrolled 26 374 participants. All-cause mortality occurred in 1219 of 9531 (12·8%) patients who received a transfusion of fresher red blood cells and 1810 of 16 843 (10·7%) in those who received older red blood cells (RR: 1·04, 95% CI: 0·98-1·12, P = 0·90, I² = 0%, high certainty for ruling out benefit of fresh blood, moderate certainty for ruling out harm of fresh blood). In six studies, in-hospital death occurred in 691 of 7479 (9·2%) patients receiving fresher red cells and 1291 of 14 757 (8·8%) receiving older red cells (RR: 1·06, 95% CI: 0·97-1·15, P = 0·81, I² = 0%, high certainty for ruling out benefit of fresh blood, moderate certainty for ruling out harm of fresh blood).

CONCLUSION

Transfusion of fresher red blood cells does not reduce overall or in-hospital mortality when compared with older red blood cells. Our results support the practice of transfusing patients with the oldest red blood cells available in the blood bank.

Effect of Short-Term vs. Long-Term Blood Storage on Mortality after Transfusion

BACKGROUND

Randomized, controlled trials have suggested that the transfusion of blood after prolonged storage does not increase the risk of adverse outcomes among patients, although most of these trials were restricted to high-risk populations and were not powered to detect small but clinically important differences in mortality. We sought to find out whether the duration of blood storage would have an effect on mortality after transfusion in a general population of hospitalized patients.

METHODS

In this pragmatic, randomized, controlled trial conducted at six hospitals in four countries, we randomly assigned patients who required a red-cell transfusion to receive blood that had been stored for the shortest duration (short-term storage group) or the longest duration (long-term storage group) in a 1:2 ratio. Only patients with type A or O blood were included in the primary analysis, since pilot data suggested that our goal of achieving a difference in the mean duration of blood storage of at least 10 days would not be possible with other blood types. Written informed consent was waived because all the patients received treatment consistent with the current standard of care. The primary outcome was in-hospital mortality, which was estimated by means of a logistic-regression model after adjustment for study center and patient blood type.

RESULTS

From April 2012 through October 2015, a total of 31,497 patients underwent randomization. Of these patients, 6761 who did not meet all the enrollment criteria were excluded after randomization. The primary analysis included 20,858 patients with type A or O blood. Of these patients, 6936 were assigned to the short-term storage group and 13,922 to the long-term storage group. The mean storage duration was 13.0 days in the short-term storage group and 23.6 days in the long-term storage group. There were 634 deaths (9.1%) in the short-term storage group and 1213 (8.7%) in the long-term storage group (odds ratio, 1.05; 95% confidence interval [CI], 0.95 to 1.16; P=0.34). When the analysis was expanded to include the 24,736 patients with any blood type, the results were similar, with rates of death of 9.1% and 8.8%, respectively (odds ratio, 1.04; 95% CI, 0.95 to 1.14; P=0.38). Additional results were consistent in three prespecified high-risk subgroups (patients undergoing cardiovascular surgery, those admitted to intensive care, and those with cancer).

CONCLUSIONS

Among patients in a general hospital population, there was no significant difference in the rate of death among those who underwent transfusion with the freshest available blood and those who underwent transfusion according to the standard practice of transfusing the oldest available blood. (Funded by the Canadian Institutes of Health Research and others; INFORM Current Controlled Trials number, ISRCTN08118744 .).

Discordance between ROTEM® clotting time and conventional tests during unfractionated heparin–based anticoagulation in intensive care patients on extracorporeal membrane oxygenation

We hypothesised that ROTEM® (Basel, Switzerland) INTEM® (ROTEM, Basel, Switzerland) clotting time (CT) would have good agreement with activated partial thromboplastin time (aPTT) in determining whether a dose adjustment should be made to the unfractionated heparin (UFH) infusion in patients on extracorporeal membrane oxygenation. All patients treated with extracorporeal membrane oxygenation over a five-year period were included for data analysis. Retrospective analysis was performed of prospectively collected data points, wherein aPTT, activated CT and ROTEM was performed simultaneously to monitor UFH–based anticoagulation. Two hundred data points were available for analysis. Turnaround time was shortest for activated CT followed by ROTEM and aPTT. Despite achieving therapeutic aPTT targets, the majority (>50%) of INTEM CT results were within normal limits. The aPTT and INTEM CT results correlated weakly (r=0.31, 95% confidence interval [0.17, 0.43]) and there was no agreement between the directional changes of aPTT and INTEM CT results on successive days (χ2 = 2.33, P=0.17). Due to relative insensitivity, INTEM CT–guided UFH titration was estimated to result in a 289% increase in incidence of up-titration, over aPTT–guided titration. The INTEM CT results (r=0.36, 95% confidence interval [0.23, 0.48]) correlated weakly with UFH infusion rates. The UFH infusion rate only explained 13% variability in INTEM CT values. While haemorrhagic complications were frequent, no major clotting complications were encountered. Our results demonstrated that aPTT and INTEM CT do not provide equivalent information to guide UFH infusion rate titration during extracorporeal membrane oxygenation. Our study suggests caution regarding the use of ROTEM for guiding UFH–based anticoagulation as it may lead to excessive UFH exposure.

Rationale and Design of the Informing Fresh versus Old Red Cell Management (INFORM) Trial: An International Pragmatic Randomized Trial

Although red blood cell transfusion is a potentially lifesaving intervention in severely anemic and acutely bleeding patients, some observational studies have suggested that prolonged red cell storage before transfusion is associated with harm. INFORM is a large, pragmatic, randomized controlled trial comparing the effect of the shorter storage with longer storage red blood cell transfusions on inhospital mortality in hospitalized patients who require a blood transfusion. The trial is being conducted in centers in Australia, Canada, Israel, and the United States and is expected to enroll 31497 patients. If the results of INFORM indicate that shorter storage red blood cell transfusion is associated with superior outcomes compared with standard issue red blood cell transfusion, consideration may be given to shortening blood storage times. If, in contrast, the INFORM trial provides no evidence of harm from longer storage red blood cells, clinicians and patients may be reassured that current blood inventory management strategies are appropriate.

Changes in fibrinolysis and severity of organ failure in sepsis: a prospective observational study using point-of-care test--ROTEM

PURPOSE

We hypothesized that the thromboelastometry (ROTEM; Pentapharm GmbH, Munich, Germany) fibrinolysis parameter "maximum lysis" (ML) would have an independent inverse association with the severity of organ failure in sepsis.

METHODS

Selected adult patients with sepsis (n = 77) were recruited within 24 hours of antibiotic commencement. Patients with Sequential Organ Failure Assessment score higher than 1 (n = 57) were followed for 72 hours. Prothrombin fragments 1 + 2, plasminogen activator inhibitor-1 (aPAI-1), ROTEM, and routine coagulation tests were measured daily along with Sequential Organ Failure Assessment scores.

RESULTS

The activity of functional aPAI-1 increased with increasing severity of organ failure (P = .01) and was higher as compared with healthy controls (95% confidence interval, -65.4 to -29.9; P < .001). There was a decreasing trend in ML with increased organ failure (P = .001); however, there was no trend in d-dimer. Among all tests, only the lower ML (ß = -0.38, P < .001) and higher international normalized ratio (INR; ß = 0.32, P = .002) values significantly contributed to greater severity of organ failure (R(2) = 0.35, F2,73 = 19.29, P < .001). Despite an increase in INR, the prothrombin fragment remained unchanged (P = .89). Strong correlations were observed between early (24 hours) increase in fibrinolysis and recovery of organ failures for 48 hours (ML: r = 0.679, P = .001; aPAI-1: r = 0.694, P < .001).

CONCLUSIONS

Lower ML and higher INR values predicted greater severity of organ failure at presentation. Further studies are required, as ROTEM could aid selection of patients and guide interventions aimed at fibrinolysis in severe sepsis.

Frequencies and specificities of red cell alloantibodies in the Southern Thai population

CONTEXT

Detailed reports of red cell alloantibody frequencies and specificities in the Thai population are limited. The aims of this study were to determine the specificity and compare the frequency of alloantibodies detected using column agglutination technology (CAT) and conventional tube techniques in blood donors and previously transfused patients.

SETTINGS AND DESIGN

WE RETROSPECTIVELY REVIEWED ANTIBODY SCREENING AND IDENTIFICATION RECORDS FOR TWO TIME PERIODS: January-December 2006 during which conventional tube techniques were used and January 2008-December 2009 when CAT was used.

RESULTS

The overall prevalence of alloantibodies in both patients and donors when using conventional tube techniques was 0.7%, for patients only was 0.9% and donors 0.6%. The most frequent antibodies detected in both groups were anti-Le(a), anti-Mi(a), anti-Le(b), anti-P1 and anti-E. When using CAT, alloantibodies were found in 0.8% of patients and 0.13% of donors with the five most common alloantibodies found in patients were anti-Mi(a), anti-E, anti-Le(a), anti-c and anti-Le(b) respectively. Similarly the common alloantibody specificities in donors were anti-Le(a), anti-Mi(a), anti-Le(b), anti-M and anti-D.

CONCLUSIONS

One of the most commonly identified alloantibodies in the Thai population studied was anti-Mi(a) suggesting that Mia positive red cells should routinely be included in antibody screening and identification in this population. For antibody screening and identification, CAT method detected immune and warm alloantibody (ies) more frequently than that associated with conventional tube techniques.

Transfusion practices in massive haemorrhage in pre-intensive and intensive care

BACKGROUND AND OBJECTIVES

Primary resuscitation for massive haemorrhage often occurs in emergency departments or operating theatres, with ongoing resuscitation in the intensive care unit (ICU). The aim of the study was to retrospectively review transfusion practice in the pre-ICU phase and ICU for patients with massive haemorrhage.

MATERIALS AND METHODS

From 1998 to 2006, we developed an electronically linked database of blood and blood product usage and laboratory data with clinical outcome. All patients who received 10 or more units of red cells and required ICU admission were included.

RESULTS

Of 238 patients who required massive transfusion, 40 died early (within 24 h of massive transfusion), out of which 16 died in pre-ICU and 24 died in ICU. Comparatively this group of patients presented in the pre-ICU phase and on ICU admission, respectively, with coagulopathy (median international normalized ratio 1.6 and 2.1) and acidosis (median base deficit -11.5 and -14 mmol/l). These patients had median ratios of fresh frozen plasma (FFP) to red blood cells of 1:3.3 and 1:1.3 in the pre-ICU and ICU phases, respectively. Severity of coagulopathy indicated by INR at ICU admission [P = 0.04; area under receiver operator curve (ROC) = 0.69] and RBC transfused (P = 0.01) in 24 h associated with mortality.

CONCLUSIONS

Patients who died early were coagulopathic before and on ICU admission and did not correct their coagulopathy. This study also shows that coagulopathy is associated with an increased risk of mortality. Early and aggressive correction of coagulopathy for patients presenting with coagulopathy may be effective in improving mortality.

A 'dangerous' group O donor: severe hemolysis in all recipients of organs from a donor with multiple red cell alloantibodies

Alloimmune hemolysis is a recognized but infrequent complication of solid organ transplantation, particularly where there is incompatibility within the ABO blood group system. We describe severe hemolysis due to passenger lymphocyte syndrome (PLS) in all three recipients of organs from a single donor with multiple red cell (RC) alloantibodies. The first patient, a liver transplant recipient, required augmentation of immunosuppression to treat immune hemolysis due to anti-B, -D, -C and -Cellano (k). This is the first description of PLS caused by alloantibody to the high incidence RC antigen, k. The two single lung transplant recipients developed hemolysis due to anti-D. Both required escalation of immunosuppression and early transfusion support. Three months posttransplant, all three patients have ongoing evidence of compensated hemolysis. This series highlights the potential for severe non-ABO-mediated immune hemolysis following solid organ transplantation. A positive donor RC antibody screen should prompt careful monitoring of organ recipients for hemolysis.

Can latent heat safely warm blood? - in vitro testing of a portable prototype blood warmer

BACKGROUND

Trauma/retrieval patients are often in shock and hypothermic. Treatment of such patients usually involves restoring their blood volume with transfusion of blood (stored at 2 degrees C - 6 degrees C) and/or crystalloids or colloids (stored at ambient temperature). Rapid infusion of these cold fluids can worsen or even induce hypothermia in these patients. Warming of intravenous fluids at accident sites has traditionally been difficult due to a lack of suitable portable fluid warmers that are not dependent on mains electrical or battery power. If latent heat, the heat released when a liquid solidifies (an inherently temperature limiting process) can warm intravenous fluids, portable devices without a reliance on electrical energy could be used to reduce the incidence of hypothermia in trauma patients.

METHODS

Rapid infusion of red cells into patients was timed to sample typical clinical flow rates. An approved dry heat blood warmer was compared with a prototype blood warmer using a supercooled liquid latent heat storage material, to warm red cells whilst monitoring inlet and outlet temperatures. To determine the effect of warming on red cell integrity compared to the normal storage lesion of blood, extracellular concentrations of potassium, lactate dehydrogenase and haemoglobin were measured in blood which had been warmed after storage at 2 degrees C - 6 degrees C for 1 to 42 days.

RESULTS

A prototype latent heat fluid warmer consistently warmed red cells from approximately 4 degrees C to approximately 35 degrees C at typical clinical flow rates. Warming of stored blood with latent heat did not affect red cell integrity more than the approved dry heat blood warmer.

CONCLUSION

Using latent heat as an energy source can satisfactorily warm cold blood or other intravenous fluids to near body temperature, without any adverse affects.

Bladder mucosal cell abnormalities and symptomatic outcome after transurethral resection of the prostate

OBJECTIVES

To identify predictors of poor symptomatic improvement after transurethral resection of the prostate (TURP), we investigated mucosal cell abnormalities in men about to undergo this procedure, and any association between these abnormalities and pre- and postoperative urinary tract symptoms.

METHODS

Bladder lavages were obtained from patients undergoing TURP for outflow obstruction during 1995 to 1996 at the Repatriation General Hospital. Pressure flow studies were obtained preoperatively, and International Prostate Symptom Scores and flow rates were obtained preoperatively and 3 months and 2 years postoperatively. Cells from bladder washings were examined flow-cytometrically for Tn antigen expression and DNA cell cycle parameters.

RESULTS

Of 192 patients recruited, 145 met the inclusion criteria. The frequency of Tn antigen expression, aneuploidy, and tetraploid aneuploidy in bladder mucosal cell washings in this group was comparable to a previous study. Weak, statistically significant associations were found between S-phase fraction and the initial International Prostate Symptom Score irrespective of whether total S-phase fraction cell numbers or categories were used. The trend of each of these associations was consistent (ie, patients with higher S-phase fraction values had more severe symptoms, poorer quality of life, and lower flow rates). The association was maintained at 3 months postoperatively but not at 2 years. Potential confounding factors did not explain the association.

CONCLUSIONS

Bladder mucosal cell abnormalities can be found in men selected to undergo TURP to relieve obstruction and are associated with poor short-term symptomatic outcome. Further studies are needed to confirm these findings, in particular any association between higher mucosal cell proliferation rates and the presence of lower urinary tract symptoms.

DNA polymorphism analysis in transfusion-associated graft-versus-host disease

During cardiac surgery for transposition of the great arteries at age 7 weeks, a female infant received blood, fresh frozen plasma and platelet transfusions. Eleven days postoperatively, she developed bloody diarrhoea, fever, an erythematous macular rash, hepatomegaly, seizures and pancytopaenia. A clinical diagnosis of transfusion related graft-versus-host disease (GVHD) was supported by skin histopathology. DNA polymorphism studies confirmed that circulating lymphocytes in peripheral blood and infiltrating cells in the skin were foreign in origin and were derived from transfused blood cells. No underlying immunodeficiency was identified. Treatment with steroids cyclosporin and antithymocyte globulin was unsuccessful and death occurred 2 months after surgery. The features of fever, rash, diarrhoea, liver dysfunction and pancytopaenia which characterize GVHD may mimic drug reactions or viral infection. In addition to histological features on skin biopsy. DNA polymorphism studies on skin and blood samples provide a unique and sensitive method to confirm GVHD. Irradiation of blood products should be considered for acutely compromised infants requiring urgent cardiac surgery.

Mutation rates at the glycophorin A and HPRT loci in uranium miners exposed to radon progeny

OBJECTIVES

To find whether a relation exists between estimated levels of exposure to radon and its progeny and mutations in hypoxanthine phosphoribosyl transferase (HPRT) and glycophorin A in a cohort of former uranium miners.

METHODS

A cohort study involving a sample of miners from the Radium Hill uranium mine in South Australia, which operated from 1952 to 1961. Radiation exposures underground at Radium Hill were estimated from historical radon gas measures with a job exposure matrix. Workers from the mine who worked exclusively above ground according to mine records were selected as controls. In 1991-2 miners were interviewed and blood taken for measurement of somatic mutations. Mutation rates for HPRT and glycophorin A were estimated with standard assay techniques.

RESULTS

Homozygous mutations of glycophorin A were increased in underground miners (P = 0.0027) and the mutation rate tended to rise with increasing exposure with the exception of the highest exposure (> 10 working level months). However, there was no association between place of work and either the hemizygous mutations of glycophorin A or the HPRT mutation.

CONCLUSIONS

There may be an association between glycophorin A mutations and previous occupational exposure to ionising radiation. However, not enough is known at present to use these assays as biomarkers for historical exposure in underground mining cohorts.

Effective use of blood in elective surgical procedures

The preoperative requests for crossmatching of blood in elective surgical procedures were studied at the Flinders Medical Centre, South Australia. The study revealed that surgeons order crossmatched blood on the basis of habit. This led to considerable time-expiry of blood, and to unnecessary use of laboratory personnel's time and reagents. The statistical information collected during the study was used to educate the surgeons to change their blood-ordering practice. In procedures where excessive blood loss is unlikely to occur, as a stand-by, a "group-and-screen" procedure was substituted for crossmatching. A firm recommendation for maximum blood order in elective surgical procedures was also made. It is estimated that this approach would save approximately $80,000 per year per 350-bed general hospital in Australia.