Association between routine cell salvage use for lower segment caesarean section and post-operative iron infusion and anemia.

PURPOSE: Intraoperative cell salvage is central to Patient Blood Management including for lower segment caesarean section. Prior to April 2020, we initiated intraoperative cell salvage during caesarean section based on risk assessment for hemorrhage and patient factors. As the pandemic broadened, we mandated intraoperative cell salvage to prevent peri-partum anemia and potentially reduce blood product usage. We examined the association of routine intraoperative cell salvage on maternal outcomes. METHODS: We conducted a single-center non-overlapping before-after study of obstetric patients undergoing lower segment caesarean section in the 2 months prior to a change in practice ('usual care = selective intraoperative cell salvage', n = 203) and the 2 months following ('mandated intraoperative cell salvage', n = 228). Recovered blood was processed when a minimal autologous reinfusion volume of 100 ml was expected. Post-operative iron infusion and length of stay were modelled using logistic or linear regression, using inverse probability weighting to account for confounding. RESULTS: More emergency lower-segment caesarean sections occurred in the Usual Care group. Compared to the Usual Care group, post-operative hemoglobin was higher and anemia cases fewer in the Mandated intraoperative cell salvage group. Rates of post-partum iron infusion were significantly lower in the Mandated intraoperative cell salvage group (OR = 0.31, 95% CI = 0.12 to 0.80, P = 0.016). No difference was found for length of stay. CONCLUSION: Routine cell salvage provision during lower segment caesarean section was associated with a significant reduction in post-partum iron infusions, increased post-operative hemoglobin and reduced anemia prevalence.

A Retrospective Cohort Study of Red Cell Alloimmunisation in Rural, Remote, and Aboriginal and Torres Strait Islander Peoples Admitted to Intensive Care in the Northern Territory, Australia.

Red cell (RC) alloantibodies occur on exposure to non-self RC antigens in transfusion and pregnancy (typically IgG and clinically significant) or in association with non-RC immune environmental factors (typically IgM and not clinically significant). In Australia, the risk of RC alloimmunisation in First Nations peoples is unknown. We assessed the epidemiology, specificity, and antecedents of RC alloimmunisation via a data linkage retrospective cohort study of Northern Territory (NT) intensive care unit (ICU) patients (2015-2019). Of 4183 total patients, 50.9% were First Nations. In First Nations versus non-First Nations patients, the period prevalence of alloimmunisation was 10.9% versus 2.3%, with 390 versus 72 prevalent alloantibodies detected in 232 versus 48 alloimmunised patients, of which 135 (34.6%) versus 52 (72.2%) were clinically significant specificities. Baseline and follow-up alloantibody testing were available for 1367 patients, in whom new incident clinically significant alloantibodies developed in 4.5% First Nations versus 1.1% non-First Nations patients. On Cox proportional hazards modelling, adjusted hazard ratios (HR) showed First Nations status (HR 2.67 (95% CI 1.05-6.80), p = 0.04) and cumulative RC unit transfusion exposure (HR 1.03 (95% CI 1.01-1.05), p = 0.01) were independent predictors of clinically significant alloimmunisation. First Nations Australian patients are at increased risk of alloimmunisation due to RC transfusion, underscoring the importance of very judicious use of RC transfusions and shared decision-making with patients. Further studies are recommended to explore the role of other (non-RC) immune host factors, given the relative high prevalence of non-clinically significant IgM alloantibodies within alloimmunised First Nations patients.

Prolonged Blood Storage and Risk of Posttransfusion Acute Kidney Injury.

BACKGROUND: Erythrocyte transfusions are independently associated with acute kidney injury. Kidney injury may be consequent to the progressive hematologic changes that develop during storage. This study therefore tested the hypothesis that prolonged erythrocyte storage increases posttransfusion acute kidney injury. METHODS: The Informing Fresh versus Old Red Cell Management (INFORM) trial randomized 31,497 patients to receive either the freshest or oldest available matching erythrocyte units and showed comparable mortality with both. This a priori substudy compared the incidence of posttransfusion acute kidney injury in the randomized groups. Acute kidney injury was defined by the creatinine component of the Kidney Disease: Improving Global Outcomes criteria. RESULTS: The 14,461 patients included in this substudy received 40,077 erythrocyte units. For patients who received more than one unit, the mean age of the blood units was used as the exposure. The median of the mean age of blood units transfused per patient was 11 days [interquartile range, 8, 15] in the freshest available blood group and 23 days [interquartile range, 17, 30] in the oldest available blood group. In the primary analysis, posttransfusion acute kidney injury was observed in 688 of 4,777 (14.4%) patients given the freshest available blood and 1,487 of 9,684 (15.4%) patients given the oldest available blood, with an estimated relative risk (95% CI) of 0.94 (0.86 to 1.02; P = 0.132). The secondary analysis treated blood age as a continuous variable (defined as duration of storage in days), with an estimated relative risk (95% CI) of 1.00 (0.96 to 1.04; P = 0.978) for a 10-day increase in the mean age of erythrocyte units. CONCLUSIONS: In a population of patients without severely impaired baseline renal function receiving fewer than 10 erythrocyte units, duration of blood storage had no effect on the incidence of posttransfusion acute kidney injury.

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.

Introduction of point-of-care ROTEM testing in the emergency department of an Australian level 1 trauma centre and its effect on blood product use.

OBJECTIVE: To assess whether the introduction of point-of-care rotational thromboelastometry (ROTEM) analysis influences blood product transfusion and coagulation management in a modern Australian level 1 trauma centre. METHODS: Retrospective blood transfusion data collection from all level 1 trauma patients with an Injury Severity Score (ISS) >12 presenting to the Royal Adelaide Hospital in 2016 and 2018. Evaluation of changes in blood product administration with the addition of point-of-care viscoelastic testing in the ED in 2018. RESULTS: A total of 774 patients were analysed with 380 in 2016 and 394 in 2018. Almost a quarter of all 2018 trauma patients (93/394) had ROTEM performed within 24 h of ED arrival, 42% of these having an ISS >25. There was a significant increase in the number of patients receiving cryoprecipitate following the introduction of ROTEM (P = 0.01). In those receiving cryoprecipitate, there was a significant reduction in subsequent platelet and fresh frozen plasma use (P < 0.001). Overall, there was a reduction in expenditure on red cells, platelets and fresh frozen plasma from 2016 to 2018. CONCLUSION: Point-of-care ROTEM was performed in a small proportion of patients, mainly those with a higher ISS. ROTEM introduction in the ED altered blood product transfusion practices for major trauma patients with an ISS >12, leading to a potentially safer transfusion strategy and cost savings for key blood products.

Maternity iron, anaemia and blood management in South Australia: a practice-based evidence for clinical practice improvement.

BACKGROUND: Anaemia at delivery is a strong modifiable risk factor for transfusion in women with a postpartum haemorrhage (PPH). A Maternity Patient Blood Management (PBM) Practice Based Evidence Clinical Practice Improvement (CPI) was conducted to optimize antenatal haemoglobin and iron stores prior to delivery. METHODS: Australian maternity PBM CPI resources (featuring algorithms on diagnosing iron deficiency with both haemoglobin and ferritin screening, as well as information on oral iron therapy for maternity patients) were introduced at a major tertiary hospital from November 2016 to March 2017. To assess the effectiveness of these resources on haemoglobin and iron stores, an interrupted time series (ITS) analysis was conducted for 11,263 deliveries from January 2016 to June 2018. The evaluation timeframe was divided into baseline (pre-CPI), pilot (during CPI) and post-pilot (post-CPI). RESULTS: In 1550 patients with haemoglobin and ferritin in the first trimester, non-anaemic iron deficiency was detected in 416 women (26·8%) and iron deficiency anaemia (IDA) in 239 women (15·41%) throughout the whole study period. The number of women with IDA increases as pregnancy progresses but applying PBM CPI shows a reduction of IDA rate in all trimesters and reduction in anaemia at delivery in the post-pilot period from baseline. More anaemic episodes were observed in the postpartum period compared to the first trimester. ITS analysis for the whole study period showed a clinically significant increase in the monthly average predelivery haemoglobin of 0·9 g/l (P = 0·16). This corresponded with a reduction in the monthly rate of anaemic patients by 18% (P = 0·12). There was a significant decrease in the rates of anaemia at delivery and decrease in red cell transfusion in anaemic women, even though the number of women with PPH was stable. The factors associated with red cell transfusion are anaemia at delivery (P < 0·001) and the incidence of PPH (P < 0·001). CONCLUSIONS: The maternity PBM CPI resources had a clinically relevant but not statistically significant effect in optimizing antenatal haemoglobin and decreasing the risk of predelivery anaemia. This study demonstrates how a CPI can modify one risk factor for blood loss, which is the anaemia at delivery, and subsequent transfusion in the perinatal period.

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.

Red cell alloimmunization is associated with development of autoantibodies and increased red cell transfusion requirements in myelodysplastic syndrome.

Up to 90% of patients with a myelodysplastic syndrome require red blood cell transfusion; nevertheless, comprehensive data on red cell alloimmunization in such patients are limited. This study evaluates the incidence and clinical impact of red cell alloimmunization in a large cohort of patients with myelodysplastic syndrome registered in the statewide South Australian-MDS registry. The median age of the 817 patients studied was 73 years, and 66% were male. The cumulative incidence of alloimmunization was 11%. Disease-modifying therapy was associated with a lower risk of alloimmunization while alloimmunization was significantly higher in patients with a revised International Prognostic Scoring System classification of Very Low, Low or Intermediate risk compared to those with a High or Very High risk (P=0.03). Alloantibodies were most commonly directed against antigens in the Rh (54%) and Kell (24%) systems. Multiple alloantibodies were present in 49% of alloimmunized patients. Although 73% of alloimmunized patients developed alloantibodies during the period in which they received their first 20 red cell units, the total number of units transfused was significantly higher in alloimmunized patients than in non-alloimmunized patients (90±100 versus 30±52; P<0.0001). In individual patients, red cell transfusion intensity increased significantly following alloimmunization (2.8±1.3 versus 4.1±2.0; P<0.0001). A significantly higher proportion of alloimmunized patients than non-alloimmunized patients had detectable autoantibodies (65% versus 18%; P<0.0001) and the majority of autoantibodies were detected within a short period of alloimmunization. In conclusion, this study characterizes alloimmunization in a large cohort of patients with myelodysplastic syndrome and demonstrates a signficant increase in red cell transfusion requirements following alloimmunization, most probably due to development of additional alloantibodies and autoantibodies, resulting in subclinical/clinical hemolysis. Strategies to mitigate alloimmunization risk are critical for optimizing red cell transfusion support.

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.

Predicting Perioperative Transfusion in Elective Hip and Knee Arthroplasty: A Validated Predictive Model.

BACKGROUND: Preoperative anemia is a significant predictor of perioperative erythrocyte transfusion in elective arthroplasty patients. However, interactions with other patient and procedure characteristics predicting transfusion requirements have not been well studied. METHODS: Patients undergoing elective primary total hip arthroplasty or total knee arthroplasty at a tertiary hospital in Adelaide, South Australia, Australia, from January 2010 to June 2014 were used to identify preoperative predictors of perioperative transfusion. A logistic regression model was developed and externally validated with an independent data set from three other hospitals in Adelaide. RESULTS: Altogether, 737 adult patients in the derivation group and 653 patients in the validation group were included. Binary logistic regression modeling identified preoperative hemoglobin (odds ratio, 0.51; 95% CI, 0.43 to 0.59; P < 0.001 for each 1 g/dl increase), total hip arthroplasty (odds ratio, 3.56; 95% CI, 2.39 to 5.30; P < 0.001), and females 65 yr of age and older (odds ratio, 3.37; 95% CI, 1.88 to 6.04; P = 0.01) as predictors of transfusion in the derivation cohort. CONCLUSIONS: Using a combination of patient-specific preoperative variables, this validated model can predict transfusion in patients undergoing elective hip and knee arthroplasty. The model may also help to identify patients whose need for transfusion may be decreased through preoperative hemoglobin optimization.

Change in transfusion practice in massively bleeding patients.

This retrospective study evaluates changes in transfusion practice and modified blood product utilisation that occurred over the course of eleven years in patients receiving massive transfusion. The mean number of fresh frozen plasma units transfused increased from 9.0 ± 7.9 in 1998 to 11.3 ± 6.7 in 2008 (p=0.03). The mean number of platelet units increased from 1.9 ± 1.3 in 1998 to 2.6 ± 1.7 in 2008 (p=0.02). The proportion of cryoprecipitate increased from 0.03 ± 0.19 in 1998 to 1.3 ± 1.6 in 2008 (p=0.001). Along with these changes was a trend toward decreased mortality (p=0.05).

Red alert - a new perspective on patterns of blood use in the South Australian public sector.

OBJECTIVES: In 2006 South Australia had a red cell issue rate, measured as product issues per 1000 population, 22.4% higher than the national average. A pilot study was undertaken to investigate the disparity in issue rates between SA and the national average with a secondary aim of establishing information on SA red cell use. METHODS: A linked electronic database was developed using clinical, epidemiological and red cell transfusion data within hospitals in the SA public sector. Aggregated red cell use across the SA public health sector was analysed by clinical variables such as Diagnosis Related Group (DRG), including specialty related groups (SRGs) and major diagnostic categories (MDCs). The DRGs that were associated with blood use were identified and applied to national hospital separations data in order to derive comparative blood utilisation rates for SA and Australia. RESULTS: Although blood issue and usage by population measure showed a significant difference of 22.4 and 22.0% respectively between SA and Australia, when measured against weighted separations the differences reduced to 7.4 and 7.1% respectively. CONCLUSION: This study showed the importance of analysing blood issues and utilisation on an activity adjusted basis rather than a raw per capita basis.