A national study of plasma use in critical care: clinical indications, dose and effect on prothrombin time

The historical origins of modern international normalized ratio targets

Prothrombin time (PT) and its derivative international normalized ratio (INR) are frequently ordered to assess the coagulation system. Plasma transfusion to treat incidentally abnormal PT/INR is a common practice with low biological plausibility and without credible evidence, yet INR targets appear in major clinical guidelines and account for the majority of plasma use at many institutions. In this article, we review the historical origins of INR targets. We recount historical milestones in the development of the PT, discovery of vitamin K antagonists (VKAs), motivation for INR standardization, and justification for INR targets in patients receiving VKA therapy. Next, we summarize evidence for INR testing to assess bleeding risk in patients not on VKA therapy and plasma transfusion for treating mildly abnormal INR to prevent bleeding in these patients. We conclude with a discussion of the parallels in misunderstanding of historic PT and present-day INR testing with lessons from the past that might help rationalize plasma transfusion in the future.

Strategies to prevent blood loss and reduce transfusion in emergency general surgery, WSES-AAST consensus paper

Emergency general surgeons often provide care to severely ill patients requiring surgical interventions and intensive support. One of the primary drivers of morbidity and mortality is perioperative bleeding. In general, when addressing life threatening haemorrhage, blood transfusion can become an essential part of overall resuscitation. However, under all circumstances, indications for blood transfusion must be accurately evaluated. When patients decline blood transfusions, regardless of the reason, surgeons should aim to provide optimal care and respect and accommodate each patient's values and target the best outcome possible given the patient's desires and his/her clinical condition. The aim of this position paper was to perform a review of the existing literature and to provide comprehensive recommendations on organizational, surgical, anaesthetic, and haemostatic strategies that can be used to provide optimal peri-operative blood management, reduce, or avoid blood transfusions and ultimately improve patient outcomes.

Plasma Transfusion and Procoagulant Product Administration in Extracorporeal Membrane Oxygenation: A Secondary Analysis of an International Observational Study on Current Practices

OBJECTIVES

To achieve optimal hemostatic balance in patients on extracorporeal membrane oxygenation (ECMO), a liberal transfusion practice is currently applied despite clear evidence. We aimed to give an overview of the current use of plasma, fibrinogen concentrate, tranexamic acid (TXA), and prothrombin complex concentrate (PCC) in patients on ECMO.

DESIGN

A prespecified subanalysis of a multicenter retrospective study. Venovenous (VV)-ECMO and venoarterial (VA)-ECMO are analyzed as separate populations, comparing patients with and without bleeding and with and without thrombotic complications.

SETTING

Sixteen international ICUs.

PATIENTS

Adult patients on VA-ECMO or VV-ECMO.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 420 VA-ECMO patients, 59% (n = 247) received plasma, 20% (n = 82) received fibrinogen concentrate, 17% (n = 70) received TXA, and 7% of patients (n = 28) received PCC. Fifty percent of patients (n = 208) suffered bleeding complications and 27% (n = 112) suffered thrombotic complications. More patients with bleeding complications than patients without bleeding complications received plasma (77% vs. 41%, p < 0.001), fibrinogen concentrate (28% vs 11%, p < 0.001), and TXA (23% vs 10%, p < 0.001). More patients with than without thrombotic complications received TXA (24% vs 14%, p = 0.02, odds ratio 1.75) in VA-ECMO, where no difference was seen in VV-ECMO. Of 205 VV-ECMO patients, 40% (n = 81) received plasma, 6% (n = 12) fibrinogen concentrate, 7% (n = 14) TXA, and 5% (n = 10) PCC. Thirty-nine percent (n = 80) of VV-ECMO patients suffered bleeding complications and 23% (n = 48) of patients suffered thrombotic complications. More patients with than without bleeding complications received plasma (58% vs 28%, p < 0.001), fibrinogen concentrate (13% vs 2%, p < 0.01), and TXA (11% vs 2%, p < 0.01).

CONCLUSIONS

The majority of patients on ECMO receive transfusions of plasma, procoagulant products, or antifibrinolytics. In a significant part of the plasma transfused patients, this was in the absence of bleeding or prolonged international normalized ratio. This poses the question if these plasma transfusions were administered for another indication or could have been avoided.

Plasma transfusion in critically Ill patients with abnormal coagulation tests before invasive procedures: A propensity-adjusted cohort study

OBJECTIVE

To evaluate the association between plasma transfusion and bleeding complications in critically ill patients with an elevated international normalized ratios undergoing invasive procedures.

METHODS

A retrospective study was conducted to evaluate a consecutive sample of critically ill adult patients undergoing invasive procedures (N = 487) with an international normalized ratio ≥ 1.5 between January 1, 2019 and December 31, 2019. Among the followed patients, 125 were excluded due to incomplete case records and 362 were finally included in this investigation. The exposure was whether plasma had been transfused within 24 h before the invasive procedure. The primary outcome was the occurrence of postprocedural bleeding complications. Secondary outcomes included transfusion of red blood cells within 24 h of the invasive procedure, and additional patient-important outcomes such as mortality and length of stay. Tests were performed with univariate and propensity-matched analyses.

RESULTS

Of the 362 study participants, 99 (27.3 %) received a preprocedural plasma transfusion. In the propensity score-matched analysis, the rate of the occurrence of postprocedural bleeding complications between two groups was not statistically different (OR, 0.605[95 % CI, 0.341-1.071]; P = .085). The rate of postoperative red blood cell transfusion in the plasma transfusion group was higher than that in the non-plasma transfusion group (35.5 % vs 21.5 %; P < .05). No statistically significant difference in mortality was observed between the two groups (29.0 % vs 31.6 %; P = .101).

CONCLUSIONS

Prophylactic plasma transfusion failed to reduce postprocedural bleeding complications in ill critically patients with a coagulopathy. Meanwhile, it was associated with increased red blood cell transfusion after invasive procedures. Findings suggest that abnormal preprocedural international normalized ratios should be managed more conservatively.

More complications and higher transfusion rate in patients with rheumatoid arthritis than osteoarthritis undergoing total hip arthroplasty

PURPOSE

Total hip arthroplasty (THA) in patients with rheumatoid arthritis (RA) has been associated with an increased risk of periprosthetic joint infection, periprosthetic fractures, dislocations, and post-operative blood transfusion. However, higher post-operative blood transfusion is unclear whether it reflects peri-operative blood loss or is characteristic of RA. This study aimed to compare the complications, allogenic blood transfusion, albumin use, and peri-operative blood loss between patients who underwent THA because of RA or osteoarthritis (OA).

METHODS

Patients undergoing cementless THA for hip RA (n = 220) or hip OA (n = 261) at our hospital between 2011 and 2021 were retrospectively enrolled. Deep vein thrombosis, pulmonary embolism, myocardial infarction, calf muscular venous thrombosis, wound complications, deep prosthetic infection, hip prosthesis dislocation, periprosthetic fractures, 30-day mortality, 90-day readmission, allogeneic blood transfusion, and albumin infusions were considered as primary outcomes, while secondary outcomes included the number of perioperative anaemia patients as well as total, intra-operative, and hidden blood loss.

RESULTS

Compared to the OA group, patients with hip RA showed significantly higher rates of wound aseptic complications, hip prosthesis dislocation, homologous transfusion, and albumin use. RA patients also showed a significantly higher prevalence of pre-operative anemia. However, no significant differences were observed between the two groups in total, intra-operative, or hidden blood loss.

CONCLUSIONS

Our study suggests that RA patients undergoing THA are at a higher risk of wound aseptic complications and hip prosthesis dislocation than patients with hip OA. Pre-operative anaemia and hypoalbuminaemia in patients with hip RA place them at a significantly higher risk of post-operative blood transfusion and use of albumin.

The Impact of Perioperative Use of Nonbiologic Disease-Modifying Anti-rheumatic Drugs on Perioperative Blood Loss and Complications in Patients Who Have Rheumatoid Arthritis Undergoing Total Knee Arthroplasty

BACKGROUND

The use of disease-modifying antirheumatic drugs (DMARDs) before total knee arthroplasty (TKA) was associated with increased risk of postoperative periprosthetic joint and wound infections as well as worse platelet function in patients who have knee rheumatoid arthritis (RA). This study investigated the effects of DMARDS on perioperative blood loss, complications, and blood transfusion in patients undergoing TKA for knee RA.

METHODS

We retrospectively enrolled patients undergoing TKA for knee RA at our hospital between 2017 and 2021 who received DMARDs (n = 73) or not (n = 84). Every RA patient was matched with patients who had osteoarthritis (OA) in a ratio of 1:1 or 1:2. Primary outcomes were intraoperative and perioperative blood losses, while secondary outcomes were complications and allogeneic transfusions.

RESULTS

The mean total (804 versus 728 mL (mL), P = .114), mean intraoperative (113 versus 101 mL, P = .488), or hidden blood losses (705 versus 640 mL, P = .340) did not differ statistically between RA patients who received DMARDs versus those who did not. RA patients who received DMARDs showed significantly greater mean total (804 versus 654 mL, P = .001), intraoperative (113 versus 75 mL, P = .002), and hidden blood losses (705 versus 560 mL, P = .016) than OA patients. No statistical differences were found in complications or allogeneic transfusions.

CONCLUSION

Although RA patients experienced greater perioperative blood loss than OA patients, there was no statistical difference in perioperative blood loss, complications, or allogeneic transfusions between RA patients who received DMARDs and those who did not.

Blasting the myth of predictive INR changes related to plasma transfusion: an academic institution's experience

INTRODUCTION

Plasma transfusion is a common therapeutic strategy used to lower international normalized ratio (INR) values in the non-emergent setting. However, due to lack of evidence of its efficacy, standardized guidelines for this practice have not been well established.

METHODS

This retrospective observational cohort study analyzed 276 inpatient encounters that involved plasma transfusions focusing on change in INR values from pre- to post-transfusion, with respect to the following predictor variables: vitamin K co-administration, number of plasma units transfused, order indication and body mass index (BMI).

RESULTS

The overall average change in the INR was 1.35. Patients who received vitamin K showed an average change of 2.51, while patients that did not receive vitamin K demonstrated an average change of 0.70. Increased numbers of plasma units transfused showed benefit up to three-unit orders. Greater decreases in the INR were observed for patients requiring plasma for anticoagulation reversal or active bleeding. There was no significant difference in the change in INR based on the BMI. By multivariate and regression analyses, the stepwise addition of each successive predictor variable demonstrated an increase in the shared variance in the outcome of the post-transfusion INR: the pre-transfusion INR and vitamin K co-administration alone was not significant (p = 0.45); the additional number of plasma units transfused was significant (R² = 0.13, p < 0.001), and; the subsequent additional plasma order indications (R² = 0.19, p < 0.001) and BMI (R² = 0.18, p < 0.001) were increasingly significant.

CONCLUSION

Taking into consideration the combination of multiple predictive factors may aid in a more efficient use of plasma products.

Stability of coagulation factors in feline fresh frozen plasma intended for transfusion after 1 year of storage

OBJECTIVES

The most common use of plasma transfusion is for haemostatic purposes, but coagulation factor activities in stored feline plasma are unknown. The concentration and stability of coagulation factors I (fibrinogen), II, V, VII, VIII, IX, X, XI and XII in feline fresh frozen plasma (fFFP) stored for 1 year were studied.

METHODS

Fifty-five units of fFFP were produced from 55 fresh whole-blood donations obtained from indoor healthy blood donor cats. Twenty-one units were stored for <2 weeks (T0) and 34 were stored for 1 year (T1). After the completion of storage, specific coagulation factor activities for factors II, V, VII, VIII, IX, X, XI and XII were tested using modified one-stage activated partial thromboplastin or prothrombin time assays. Fibrinogen was determined using the Clauss method.

RESULTS

Significantly decreased activities were observed for factors II (T0: 101.94% ± 19.06%; T1: 73.23% ± 39.06% [P = 0.001]), VII (T0: 102.78% ± 24.69%; T1: 60.08% ± 38.17% [P <0.001]), VIII (T0: 77.52% ± 30.39%; T1: 50.32% ± 23.8% [P = 0.001]), XI (T0: 88.76% ± 22.73%; T1: 66.28% ± 22.2% [P = 0.001]) and XII (T0: 89.50% ± 21.85%; T1: 55.46% ± 23.18% [P <0.001]) when comparing units at time 0 and after 1 year of storage. No significant difference was observed for factors IX (T0: 84.86% ± 29.35%; T1: 71.37% ± 22.23% [P = 0.064]) and X (T0: 96.24% ± 25.1%; T1: 83.91% ± 49.54% [P = 0.236]). Unexpectedly, a significant increase was observed for factor V (T0: 71.94% ± 24.14%; T1: 97.89% ± 62.33%; P = 0.046). Fibrinogen was 2.76 ± 1.09 g/l at T1. Factors VIII, XII and VII had the lowest mean activities after 1 year.

CONCLUSIONS AND RELEVANCE

Although a decrease in most coagulation factors activities was noted with storage, 1-year-old fFFP was haemostatically active in vitro. The most suitable factors for quality control assessment of fFFP are factors VII and VIII. Approximately 13-20 ml/kg of fFFP is required to administer a minimum of 10 IU/kg coagulation factor activity.

Plasma transfusion practices: A multicentre electronic audit

BACKGROUND AND OBJECTIVES

Plasma is often transfused to patients with bleeding or requiring invasive procedures and with abnormal tests of coagulation. Chart audits find half of plasma transfusions unnecessary, resulting in avoidable complications and costs. This multicentre electronic audit was conducted to determine the proportion of plasma transfused without an indication and/or at a sub-therapeutic dose.

METHODS

Data were extracted on adult inpatients in 2017 at five academic sites from the hospital electronic chart, laboratory information systems and the Canadian Institute for Health Information Discharge Abstract Database. Electronic criteria for plasma transfusion outside recommended indications were: (1) international normalized ratio (INR) < 1.5 with no to moderate bleeding; (2) INR ≥ 1.5, with no to mild bleeding and no planned procedures; and (3) no INR before or after plasma infusion. Sub-therapeutic dose was defined as ≤2 units transfused.

RESULTS

In 1 year, 2590 patients received 6088 plasma transfusions encompassing 11,490 units of plasma occurred at the five sites. 77.7% of events were either outside indications or under-dosed. Of these, 34.8% of plasma orders had no indication identified, and 62% of these occurred in non-bleeding patients and no planned procedure with an isolated elevated INR. 70.7% of transfusions were under-dosed. Most plasma transfusions occurred in the intensive care unit or the operating room. Inter-hospital variability in peri-transfusion testing and dosing was observed.

CONCLUSION

The majority of plasma transfusions are sub-optimal. Local hospital culture may be an important driver. Electronic audits, with definitions employed in this study, may be a practical alternative to costly chart audits.

Patterns and determinants of blood transfusion in intensive care in Sweden between 2010 and 2018: A nationwide, retrospective cohort study

Background

Intensive care unit (ICU) patients are transfused with blood products for a number of reasons, from massive ongoing hemorrhage, to mild anemia following blood sampling, combined with bone marrow depression due to critical illness. There's a paucity of data on transfusions in ICUs and most studies are based on audits or surveys. The aim of this study was to provide a complete picture of ICU‐related transfusions in Sweden.

Methods

We conducted a register based retrospective cohort study with data on all adult patient admissions from 82 of 84 Swedish ICUs between 2010 and 2018, as recorded in the Swedish Intensive Care Register. Transfusions were obtained from the SCANDAT‐3 database. Descriptive statistics were computed, characterizing transfused and nontransfused patients. The distribution of blood use comparing different ICUs was investigated by computing the observed proportion of ICU stays with a transfusion, as well as the expected proportion.

Results

In 330,938 ICU episodes analyzed, at least one transfusion was administered for 106,062 (32%). For both red‐cell units and plasma, the fraction of patients who were transfused decreased during the study period from 31.3% in 2010 to 24.6% in 2018 for red‐cells, and from 16.6% in 2010 to 9.4% in 2018 for plasma. After adjusting for a range of factors, substantial variation in transfusion frequency remained, especially for plasma units.

Conclusion

Despite continuous decreases in utilization, transfusions remain common among Swedish ICU patients. There is considerable unexplained variation in transfusion rates. More research is needed to establish stronger critiera for when to transfuse ICU patients.

Coagulation test understanding and ordering by medical trainees: Novel teaching approach

Background

Coagulation testing provides a prime opportunity to make an impact on the reduction of unnecessary laboratory test ordering, as there are clear indications for testing. Despite the prothrombin time/international normalized ratio and activated partial thromboplastin time being validated for specific clinical indications, they are frequently ordered as screening tests and often ordered together, suggesting a gap in understanding of coagulation.

Methods

Based on a needs assessment, we developed an online educational module on coagulation for trainees, incorporating education on testing cost, specificity, and sensitivity. Fifty participating resident physicians and medical students completed a validated premodule quiz, postmodule quiz after completion of the module, and a latent quiz 3 to 6 months after to assess longer‐term knowledge retention. Trainees provided responses regarding their subjective laboratory test‐ordering practices before and after module completion.

Results

The median premodule quiz score was 67% (n = 50; range, 24%‐86%) with an increase of 24% to a median postmodule quiz score of 91% (n = 50; range, 64%‐100%). There was evidence of sustained knowledge acquisition with a latent quiz median score of 89% (n = 40; range, 67%–100%). Trainees were more likely to consider the sensitivity, specificity, and cost of laboratory investigations before ordering them following completion of the educational module.

Conclusions

Using the expertise of medical educators and incorporating trainee feedback, we employed a novel approach to the teaching of coagulation to maximize its approachability and clinical relevance. We found sustained knowledge retention regarding coagulation and appropriate coagulation test ordering, and a subjective change to trainee ordering habits following participation in our educational intervention.

Single Plasma Unit Transfusions in Adults Are Either Unnecessary or Underdosed

OBJECTIVES

Previous studies of blood product use have shown higher inappropriate use of plasma compared with other products. Given typical weight-based dosing of plasma, we hypothesized that single plasma transfusions in adults would either be a nontherapeutic dose or outside clinical guidelines.

METHODS

A single-center, retrospective review of nonoperative, nonapheresis plasma use was conducted from January 2020 to April 2020. Plasma transfusions were reviewed for compliance with clinical guidelines formulated at our institution as well as national and society guidelines.

RESULTS

During the study period, 313 units of plasma were transfused. Of these, 152 (48.6%) were given against institutional or national guidelines, 126 plasma units (40.3%) were transfused as single units, and 187 (59.7%) were given as part of multiple-unit transfusions. All single-unit plasma transfusions during the study period were either underdosed or outside clinical guidelines. Units transfused with an indication of "Other" were significantly more likely to be outside clinical guidelines.

CONCLUSIONS

Nonoperative, nonapheresis plasma use is often outside clinical guidelines. Single-unit plasma transfusions in adults are a potential target for patient blood management programs seeking to minimize unnecessary plasma use.

Causes of an elevated international normalized ratio in the intensive care unit and the implications for plasma transfusion

BACKGROUND

The presence of an elevated international normalized ratio (INR) is common in patients in the intensive care unit (ICU), but the cause rarely determined. These patients are at risk to receive prophylactic plasma prior to invasive procedures.

STUDY DESIGN AND METHODS

Samples from patients with an INR of 1.5 or greater were frozen and subsequently thawed and assayed for procoagulant and anticoagulant clotting factors and anti-Xa to determine the likely cause of the INR. Samples showing a low FVII, FX, PC, and PS were categorized as a vitamin K deficiency pattern. Samples showing a low FV, low or normal fibrinogen, and high FVIII were categorized as a liver disease pattern. Samples showing an anti-Xa >0.01 IU/ml were assayed for anti-Xa DOACs. Samples which could not be categorized were grouped as equivocal.

RESULTS

A total of 48 samples were obtained over a 6-month period. Nineteen showed a Vitamin K deficiency pattern, 17 a liver disease pattern, 7 showed an anti-Xa DOAC and 5 were equivocal. High FVIII and D-dimers and reduced levels of the anticoagulant proteins were present in the majority of the samples. FVII levels correlated inversely with the INR (r = -0. 81), as did FX (r = -0.67) but not FV (r = -0.04) nor fibrinogen (r = -0.15).

CONCLUSION

Transfusion of plasma to reverse an elevated INR in the ICU should be discouraged since such a practice is either avoidable by the use of vitamin K or inappropriate in the case of liver disease or an anti-Xa DOAC.

Plasma trial: Pilot randomized clinical trial to determine safety and efficacy of plasma transfusions

BACKGROUND

Plasma is frequently administered to patients with prolonged INR prior to invasive procedures. However, there is limited evidence evaluating efficacy and safety.

STUDY DESIGN AND METHODS

We performed a pilot trial in hospitalized patients with INR between 1.5 and 2.5 undergoing procedures conducted outside the operating room. We excluded patients undergoing procedures proximal to the central nervous system, platelet counts <40,000/μl, or congenital or acquired coagulation disorders unresponsive to plasma. We randomly allocated patients stratified by hospital and history of cirrhosis to receive plasma transfusion (10-15 cc/kg) or no transfusion. The primary outcome was change in hemoglobin concentration within 2 days of procedure.

RESULTS

We enrolled 57 patients, mean age 56.0, 34 (59.6%) with cirrhosis, and mean INR 1.92 (SD = 0.27). In the intention to treat analysis, there were 10 of 27 (38.5%) participants in the plasma arm with a post procedure INR <1.5 and one of 30 (3.6%) in the no treatment arm (p < .01). The mean INR after receiving plasma transfusion was -0.24 (SD 0.26) lower than baseline. The change from pre-procedure hemoglobin level to lowest level within 2 days was -0.6 (SD = 1.0) in the plasma transfusion arm and -0.4 (SD = 0.6) in the no transfusion arm (p = .29). Adverse outcomes were uncommon.

DISCUSSION

We found no differences in change in hemoglobin concentration in those treated with plasma compared to no treatment. The change in INR was small and corrected to less than 1.5 in minority of patients. Large trials are required to establish if plasma is safe and efficacious.

Transfusion in Pediatric Patients: Review of Evidence-Based Guidelines

Children require transfusion of blood components for a vast array of medical conditions, including acute hemorrhage, hematologic and nonhematologic malignancies, hemoglobinopathy, and allogeneic and autologous stem cell transplant. Evidence-based literature on pediatric transfusion practices is limited, particularly for non-red blood cell products, and many recommendations are extrapolated from studies in adult populations. Recognition of these knowledge gaps has led to increasing numbers of clinical trials focusing on children and establishment of pediatric transfusion working groups in recent years. This article reviews existing literature on pediatric transfusion therapy within the larger context of analogous data in adult populations.

Transfusion in critical care: Past, present and future

Anaemia and coagulopathy are common in critically ill patients and are associated with poor outcomes, including increased risk of mortality, myocardial infarction, failure to be liberated from mechanical ventilation and poor physical recovery. Transfusion of blood and blood products remains the corner stone of anaemia and coagulopathy treatment in critical care. However, determining when the benefits of transfusion outweigh the risks of anaemia may be challenging in some critically ill patients. Therefore, the European Society of Intensive Care Medicine prioritised the development of a clinical practice guideline to address anaemia and coagulopathy in non-bleeding critically ill patients. The aims of this article are to: (1) review the evolution of transfusion practice in critical care and the direction for future developments in this important area of transfusion medicine and (2) to provide a brief synopsis of the guideline development process and recommendations in a format designed for busy clinicians and blood bank staff. These clinical practice guidelines provide recommendations to clinicians on how best to manage non-bleeding critically ill patients at the bedside. More research is needed on alternative transfusion targets, use of transfusions in special populations (e.g., acute neurological injury, acute coronary syndromes), use of anaemia prevention strategies and point-of-care interventions to guide transfusion strategies.

Retrospective evaluation of the indications, safety and effects of fresh frozen plasma transfusions in 36 cats (2014-2018)

OBJECTIVES

The goals of this study were to classify the indications, risks, effects on coagulation times and outcomes of cats receiving fresh frozen plasma (FFP) transfusions in clinical practice.

METHODS

This was a retrospective study of FFP transfusions administered in two referral hospitals from 2014 to 2018. Transfusion administration forms and medical records were reviewed. Information was collected on indication, underlying condition, coagulation times and signs of transfusion reactions. Seven-day outcomes after FFP administration were also evaluated when available.

RESULTS

Thirty-six cats received 54 FFP transfusions. Ninety-four percent of cats were administered FFP for treatment of a coagulopathy. Twenty cats had paired coagulation testing before and after FFP administration. Eighteen of these cats had improved coagulation times after receiving 1-3 units of FFP. Eight of the 36 cats had probable transfusion reactions (14.8% of 54 FFP transfusions). These reactions included respiratory signs (n = 4), fever (n = 2) and gastrointestinal signs (n = 2). Five of the eight cats with probable reactions had received packed red blood cells contemporaneously. Overall mortality rate during hospitalization was 29.7%, with 52.8% (n = 19/36) of cats confirmed to be alive 7 days after discharge.

CONCLUSIONS AND RELEVANCE

This retrospective study shows that FFP transfusions improve coagulation times in cats. Transfusion reactions are a risk, and risk-benefit ratios must be measured prior to administration and possible reactions monitored. In the study cats, the FFP transfusions appeared to be a tolerable risk given the benefit to prolonged coagulation times.

Comparison of international normalized ratio determined by point-of-care to standard laboratory testing before and after reversal of heparin in cardiac surgery

STUDY OBJECTIVE

To compare point-of-care (POC) of international normalized ratio to laboratory-derived values before and after cardiopulmonary bypass, with the primary aim of evaluating for any change in the relationship between the tests.

METHODS

This is a prospective observational study with 50 patients undergoing cardiac surgery enrolled. The International normalized ratio measured at two time points, precardiopulmonary bypass and after heparin reversal with protamine using both POC i-STAT and standard laboratory analysis for both time points. A difference of 0.2 between tests at either time point was considered clinically significant based on previous literature. A paired t test was used to test for a changing or statistically significant mean difference between tests. At both time points values were categorized into absolute difference of more than 0.2 or less than 0.2, and a Fisher's exact test was used to determine if an association existed between heparin reversal and a difference more than 0.2. Bland-Altman plots were also evaluated for agreement.

RESULTS

A statistically and clinically significant mean difference [0.09 vs. 0.25, difference -0.163 95% confidence interval (-0.25, -0.08), P = 0.003] was seen between the laboratory and POC tests when pre and postheparin reversal samples were compared. A significantly greater number of patients had a clinically relevant difference between the tests post compared with pre (four patients vs. 18 patients, P = 0.001). Linear regression analysis of the difference compared with the means, showed significant correlation suggesting the presence of a proportional bias (pre r = 0.488, P = <0.01, post r = 0.571, P = <0.01).

CONCLUSION

Clinically significant differences exist between POC and laboratory testing of international normalized ratio after heparin reversal during cardiac surgery. ClinicalTrials.gov Identifier NCT03267823.

Current perspective on fibrinogen concentrate in critical bleeding

INTRODUCTION

. Massive hemorrhage continues to be a treatable cause of death. Its management varies from prefixed ratio-driven administration of blood components to goal-directed therapy based on point-of-care testing and administration of coagulation factor concentrates.

AREAS COVERED

. We review the current role of fibrinogen concentrate (FC) for the management of massive hemorrhage, either administered without coagulation testing in life-threatening hemorrhage, or within an algorithm based on viscoelastic hemostatic assays and plasma fibrinogen level. We identified relevant guidelines, meta-analyzes, randomized controlled trials, and observational studies that included indications, dosage, and adverse effects of FC, especially thromboembolic events.

EXPERT OPINION

. Moderate- to high-grade evidence supports the use of FC for the treatment of severe hemorrhage in trauma and cardiac surgery; a lower grade of evidence is available for its use in postpartum hemorrhage and end-stage liver disease. Pre-emptive FC administration in non-bleeding patients is not recommended. FC should be administered early, in a goal-directed manner, guided by early amplitude of clot firmness parameters (A5- or A10-FIBTEM) or hypofibrinogenemia. Further investigation is required into the early use of FC, as well as its potential advantages over cryoprecipitate, and whether or not its administration at high doses leads to a greater risk of adverse events.

Retrospective evaluation of fresh frozen plasma use in 121 cats: 2009-2016

OBJECTIVES

To document indications for fresh frozen plasma (FFP) use in cats, doses administered, and frequency of adverse transfusion reactions (ATR).

DESIGN

Retrospective observational study from January 2009 to November 2016.

SETTING

Large urban referral and emergency facility.

ANIMALS

One hundred twenty-one client-owned cats that received FFP.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Signalment, indication(s), dose, pre- and posttransfusion total plasma protein, prothrombin time, activated partial thromboplastin time, as well as possible ATR, primary disease process, and outcome were recorded. Doppler blood pressure was increased posttransfusion (mean pre 99.5 ± 30.8 mm Hg; post 108.5 ± 32.5 mm Hg, P = .027). Cats were significantly less likely to be coagulopathic posttransfusion (P < 0.001). Most common indications were suspected coagulopathy (n = 105, 83%), hemorrhage (n = 45, 35%), and hypotension (n = 32, 25%). Median dose was 6 mL/kg (interquartile range = 3 mL/kg) and was negatively correlated with body weight (r = -.598, P < 0.001). Possible ATR occurred in 17 of 108 (16%, 95% confidence interval [CI], 10-24%) of transfusions. Increased body temperature was most common in 11 of 108 (10%, 95% CI, 5-18%), followed by tachypnea/dyspnea in 8 of 108 (7%, 95% CI, 3-13%). Common primary disease processes included liver disease (n = 41, 34%), neoplasia (n = 19, 16%), and sepsis (n = 15, 12%). Overall mortality was 54%. Improvement of clotting times was associated with increased odds of survival (odds ratio = 2.4; 95% CI, 1.1-5.3; P = 0.023).

CONCLUSIONS

Clinician justifications for FFP transfusions are comparable to that reported in dogs; however, the mL/kg dose is lower. Coagulopathy and blood pressure significantly improve posttransfusion. Possible ATR were as frequent as that reported with feline packed RBCs transfusions and classified as mild.

Coagulation status of critically ill patients with and without liver disease assessed using a novel thrombin generation analyzer

The liver synthesizes the majority of pro- and anti-coagulant and fibrinolytic proteins, and during liver dysfunction synthesis of these proteins is reduced. The end point of conventional hemostatic tests, such as the prothrombin time (PT), occurs when only 5% of thrombin generation (TG) has taken place and is not sensitive to the effects of natural anti-coagulants. The aim of this study was to determine whether TG in the presence of thrombomodulin (TM) provides more useful information about coagulation potential, in comparison to the PT. Analysis was performed on ST Genesia, a novel TG analyzer from Diagnostica Stago. TG was measured using STG-Thromboscreen, a reagent containing an intermediate concentration of human tissue factor (TF) ± rabbit TM to account for anti-coagulant protein C (PC) activity. Platelet-poor plasma (PPP) samples were from the Intensive Care Study of Coagulopathy-2 (ISOC-2), which recruited patients admitted to critical care with a prolonged PT (3 seconds above the reference range). Despite a prolonged PT, 48.0% and 60.7% of patients in the liver and non-liver groups had TG parameters within the normal range. Addition of TM reduced TG by 34.5% and 41.8% in the liver and non-liver groups, respectively. Interestingly, fresh frozen plasma (FFP) transfusion had no impact on TG. Measurement of TG with addition of TM provides a more informative assessment of coagulation capacity and indicates that hemostasis is balanced in patients with liver disease during critical illness, despite conventional tests suggesting that bleeding risk is increased.

Transfusion strategies in non-bleeding critically ill adults: a clinical practice guideline from the European Society of Intensive Care Medicine

OBJECTIVE

To develop evidence-based clinical practice recommendations regarding transfusion practices in non-bleeding, critically ill adults.

DESIGN

A task force involving 13 international experts and three methodologists used the GRADE approach for guideline development.

METHODS

The task force identified four main topics: red blood cell transfusion thresholds, red blood cell transfusion avoidance strategies, platelet transfusion, and plasma transfusion. The panel developed structured guideline questions using population, intervention, comparison, and outcomes (PICO) format.

RESULTS

The task force generated 16 clinical practice recommendations (3 strong recommendations, 13 conditional recommendations), and identified five PICOs with insufficient evidence to make any recommendation.

CONCLUSIONS

This clinical practice guideline provides evidence-based recommendations and identifies areas where further research is needed regarding transfusion practices and transfusion avoidance in non-bleeding, critically ill adults.

Thromboelastography Predicts Thromboembolism in Critically Ill Coagulopathic Patients

OBJECTIVES

Critically ill patients with deranged conventional coagulation tests are often perceived to have an increased bleeding risk. Whether anticoagulant prophylaxis for these patients should be withheld is contentious. This study assessed the ability of using in vitro clot strength, as measured by thromboelastography, to predict thromboembolism in patients with abnormal coagulation profiles.

DESIGN

Prospective cohort study.

SETTING

A tertiary ICU.

PATIENTS

Two-hundred and fifteen critically ill coagulopathic patients with thrombocytopenia and/or a derangement in at least one conventional coagulation test (international normalized ratio or activated partial thromboplastin time) within 48 hours of ICU admission.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Thromboelastography was performed for all study patients, and plasma thrombotic biomarkers were measured in a nested cohort (n = 40). Of the 215 patients included, 34 patients (16%) developed subsequent thromboembolism-predominantly among those with a normal (maximum amplitude, 54-72 mm) or increased (maximum amplitude, > 72 mm) in vitro clot strength on thromboelastography (91%; area under the receiver-operating characteristic curve, 0.74; 95% CI, 0.64-0.83). The ability of the maximum amplitude to predict thromboembolism was comparable to plasma P-selectin concentrations (thromboembolism, 78.3 ng/mL vs no thromboembolism, 59.5 ng/mL; p = 0.031; area under the receiver-operating characteristic curve, 0.73; 95% CI, 0.52-0.95). In addition, patients with an increased maximum amplitude were also less likely to receive blood product transfusions within 24 hours of testing compared with those with a subnormal maximum amplitude (12.8% vs 69.2%, respectively; area under the receiver-operating characteristic curve, 0.74; 95% CI, 0.67-0.80).

CONCLUSIONS

In patients with abnormal coagulation profiles, an increased in vitro clot strength on thromboelastography was associated with an increased risk of thromboembolism, and a reduced risk of requiring transfusion compared with those with a normal or reduced in vitro clot strength.

Influence of factor XII deficiency on activated partial thromboplastin time (aPTT) in critically ill patients

FXII deficiency results in spontaneous prolongation of activated partial thromboplastin time (aPTT), which is widely used to monitor thromboprophylaxis. Misinterpretation of spontaneously prolonged aPTT may result in omission of thromboembolic treatment or even unnecessary transfusion of blood products. This retrospective analysis was performed to calculate a threshold level of FXII resulting in aPTT prolongation. 79 critically ill patients with spontaneous prolongation of aPTT were included. A correlation analysis and a ROC curve for aPTT prolongation predicted by FXII level were created to find the FXII threshold level. Prolongation of aPTT was associated with disease severity. A significant inverse proportionality between FXII and aPTT was seen. A ROC curve for aPTT prolongation, predicted by FXII level (AUC 0.85; CI 0.76–0.93), revealed a FXII threshold level of 42.5%. Of our patients 50.6% experienced a FXII deficiency, in 80.0% of whom we found aPTT to be prolonged without a significantly higher bleeding rate. The FXII deficiency was more common in patients with higher SAPS3 scores, septic shock, transfusion of red blood cells and platelet concentrates as well as in patients receiving renal replacement therapy. Patients with a FXII deficiency and prolonged aPTT less often received anticoagulatory therapy although they were more severely ill. The rate of thromboembolic events was higher in these patients although the difference was not statistically significant. Of all patients with spontaneous aPTT prolongation 50.6% had a FXII level of 42.5% or less. Those patients received insufficient thromboembolic prophylaxis.

Strategies to minimize intraoperative blood loss during major surgery

Background

Reducing operative blood loss improves patient outcomes and reduces healthcare costs. The aim of this article was to review current surgical, anaesthetic and haemostatic intraoperative blood conservation strategies.

Methods

This narrative review was based on a literature search of relevant databases up to 31 July 2019 for publications relevant to reducing blood loss in the surgical patient.

Results

Interventions can begin early in the preoperative phase through identification of patients at high risk of bleeding. Directly acting anticoagulants can be stopped 48 h before most surgery in the presence of normal renal function. Aspirin can be continued for most procedures. Intraoperative cell salvage is recommended when anticipated blood loss is greater than 500 ml and this can be continued after surgery in certain situations. Tranexamic acid is safe, cheap and effective, and routine administration is recommended when anticipated blood loss is high. However, the optimal dose, timing and route of administration remain unclear. The use of topical agents, tourniquet and drains remains at the discretion of the surgeon. Anaesthetic techniques include correct patient positioning, avoidance of hypothermia and regional anaesthesia. Permissive hypotension may be beneficial in selected patients. Promising haemostatic strategies include use of pharmacological agents such as desmopressin, prothrombin complex concentrate and fibrinogen concentrate, and use of viscoelastic haemostatic assays.

Conclusion

Reducing perioperative blood loss requires a multimodal and multidisciplinary approach. Although high-quality evidence exists in certain areas, the overall evidence base for reducing intraoperative blood loss remains limited.

Prophylactic plasma transfusion for patients without inherited bleeding disorders or anticoagulant use undergoing non-cardiac surgery or invasive procedures

BACKGROUND

In the absence of bleeding, plasma is commonly transfused to people prophylactically to prevent bleeding. In this context, it is transfused before operative or invasive procedures (such as liver biopsy or chest drainage tube insertion) in those considered at increased risk of bleeding, typically defined by abnormalities of laboratory tests of coagulation. As plasma contains procoagulant factors, plasma transfusion may reduce perioperative bleeding risk. This outcome has clinical importance given that perioperative bleeding and blood transfusion have been associated with increased morbidity and mortality. Plasma is expensive, and some countries have experienced issues with blood product shortages, donor pool reliability, and incomplete screening for transmissible infections. Thus, although the benefit of prophylactic plasma transfusion has not been well established, plasma transfusion does carry potentially life-threatening risks.

OBJECTIVES

To determine the clinical effectiveness and safety of prophylactic plasma transfusion for people with coagulation test abnormalities (in the absence of inherited bleeding disorders or use of anticoagulant medication) requiring non-cardiac surgery or invasive procedures.

SEARCH METHODS

We searched for randomised controlled trials (RCTs), without language or publication status restrictions in: Cochrane Central Register of Controlled Trials (CENTRAL; 2017 Issue 7); Ovid MEDLINE (from 1946); Ovid Embase (from 1974); Cumulative Index to Nursing and Allied Health Literature (CINAHL; EBSCOHost) (from 1937); PubMed (e-publications and in-process citations ahead of print only); Transfusion Evidence Library (from 1950); Latin American Caribbean Health Sciences Literature (LILACS) (from 1982); Web of Science: Conference Proceedings Citation Index-Science (CPCI-S) (Thomson Reuters, from 1990); ClinicalTrials.gov; and World Health Organization (WHO) International Clinical Trials Registry Search Platform (ICTRP) to 28 January 2019.

SELECTION CRITERIA

We included RCTs comparing: prophylactic plasma transfusion to placebo, intravenous fluid, or no intervention; prophylactic plasma transfusion to alternative pro-haemostatic agents; or different haemostatic thresholds for prophylactic plasma transfusion. We included participants of any age, and we excluded trials incorporating individuals with previous active bleeding, with inherited bleeding disorders, or taking anticoagulant medication before enrolment.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included five trials in this review, all were conducted in high-income countries. Three additional trials are ongoing. One trial compared fresh frozen plasma (FFP) transfusion with no transfusion given. One trial compared FFP or platelet transfusion or both with neither FFP nor platelet transfusion given. One trial compared FFP transfusion with administration of alternative pro-haemostatic agents (factors II, IX, and X followed by VII). One trial compared the use of different transfusion triggers using the international normalised ratio measurement. One trial compared the use of a thromboelastographic-guided transfusion trigger using standard laboratory measurements of coagulation. Four trials enrolled only adults, whereas the fifth trial did not specify participant age. Four trials included only minor procedures that could be performed by the bedside. Only one trial included some participants undergoing major surgical operations. Two trials included only participants in intensive care. Two trials included only participants with liver disease. Three trials did not recruit sufficient participants to meet their pre-calculated sample size. Overall, the quality of evidence was low to very low across different outcomes according to GRADE methodology, due to risk of bias, indirectness, and imprecision. One trial was stopped after recruiting two participants, therefore this review's findings are based on the remaining four trials (234 participants). When plasma transfusion was compared with no transfusion given, we are very uncertain whether there was a difference in 30-day mortality (1 trial comparing FFP or platelet transfusion or both with neither FFP nor platelet transfusion, 72 participants; risk ratio (RR) 0.38, 95% confidence interval (CI) 0.13 to 1.10; very low-quality evidence). We are very uncertain whether there was a difference in major bleeding within 24 hours (1 trial comparing FFP transfusion vs no transfusion, 76 participants; RR 0.33, 95% CI 0.01 to 7.93; very low-quality evidence; 1 trial comparing FFP or platelet transfusion or both with neither FFP nor platelet transfusion, 72 participants; RR 1.59, 95% CI 0.28 to 8.93; very low-quality evidence). We are very uncertain whether there was a difference in the number of blood product transfusions per person (1 trial, 76 participants; study authors reported no difference; very low-quality evidence) or in the number of people requiring transfusion (1 trial comparing FFP or platelet transfusion or both with neither FFP nor platelet transfusion, 72 participants; study authors reported no blood transfusion given; very low-quality evidence) or in the risk of transfusion-related adverse events (acute lung injury) (1 trial, 76 participants; study authors reported no difference; very low-quality evidence). When plasma transfusion was compared with other pro-haemostatic agents, we are very uncertain whether there was a difference in major bleeding (1 trial; 21 participants; no events; very low-quality evidence) or in transfusion-related adverse events (febrile or allergic reactions) (1 trial, 21 participants; RR 9.82, 95% CI 0.59 to 162.24; very low-quality evidence). When different triggers for FFP transfusion were compared, the number of people requiring transfusion may have been reduced (for overall blood products) when a thromboelastographic-guided transfusion trigger was compared with standard laboratory tests (1 trial, 60 participants; RR 0.18, 95% CI 0.08 to 0.39; low-quality evidence). We are very uncertain whether there was a difference in major bleeding (1 trial, 60 participants; RR 0.33, 95% CI 0.01 to 7.87; very low-quality evidence) or in transfusion-related adverse events (allergic reactions) (1 trial; 60 participants; RR 0.33, 95% CI 0.01 to 7.87; very low-quality evidence). Only one trial reported 30-day mortality. No trials reported procedure-related harmful events (excluding bleeding) or quality of life.

AUTHORS' CONCLUSIONS

Review findings show uncertainty for the utility and safety of prophylactic FFP use. This is due to predominantly very low-quality evidence that is available for its use over a range of clinically important outcomes, together with lack of confidence in the wider applicability of study findings, given the paucity or absence of study data in settings such as major body cavity surgery, extensive soft tissue surgery, orthopaedic surgery, or neurosurgery. Therefore, from the limited RCT evidence, we can neither support nor oppose the use of prophylactic FFP in clinical practice.

Review of current transfusion therapy and blood banking practices

Transfusion Medicine is a dynamically evolving field. Recent high-quality research has reshaped the paradigms guiding blood transfusion. As increasing evidence supports the benefit of limiting transfusion, guidelines have been developed and disseminated into clinical practice governing optimal transfusion of red cells, platelets, plasma and cryoprecipitate. Concepts ranging from transfusion thresholds to prophylactic use to maximal storage time are addressed in guidelines. Patient blood management programs have developed to implement principles of patient safety through limiting transfusion in clinical practice. Data from National Hemovigilance Surveys showing dramatic declines in blood utilization over the past decade demonstrate the practical uptake of current principles guiding patient safety. In parallel with decreasing use of traditional blood products, the development of new technologies for blood transfusion such as freeze drying and cold storage has accelerated. Approaches to policy decision making to augment blood safety have also changed. Drivers of these changes include a deeper understanding of emerging threats and adverse events based on hemovigilance, and an increasing healthcare system expectation to align blood safety decision making with approaches used in other healthcare disciplines.

On-label compared to off-label four-factor prothrombin complex concentrate use: a retrospective, observational study

BACKGROUND

Four-factor prothrombin complex concentrate (4F-PCC) is US Food and Drug Administration approved for the urgent reversal of coagulation factor deficiency induced by a vitamin K antagonist complicated by acute major bleeding or in situations in which invasive procedures are urgently needed. Although recent evidence suggests the superiority of 4F-PCC over plasma for on-label indications, the off-label use of 4F-PCC has not been rigorously studied.

STUDY DESIGN AND METHODS

Eighty-nine patients receiving 4F-PCC at a single institution from July 2016 to December 2017 were retrospectively analyzed. Two cohorts, "On-Label" and "Off-Label" uses of 4F-PCC, were evaluated, comparing patient characteristics, blood utilization, and clinical outcomes including in-hospital mortality.

RESULTS

Patients receiving 4F-PCC for off-label reasons (n = 46) were younger and sicker compared to those receiving 4F-PCC for on-label reasons (n = 43). Notably, the mortality rate for off-label use was approximately twofold greater than the mortality rate for on-label use (26 of 46 [56.5%] vs. 12 of 43 [27.9%]; p = 0.006). Patients receiving 4F-PCC for off-label reasons received more units per patient of each blood component than their on-label counterparts. The average cost estimate per patient for 4F-PCC was similar (approx. $4300) in each cohort.

CONCLUSION

4F-PCC is an effective but expensive treatment option for those requiring urgent reversal of vitamin K antagonist-induced coagulopathy. However, providers should be conscious of the high costs and questionable efficacy when using 4F-PCC off-label.

Prediction of bleeding by thromboelastography in ICU patients with haematological malignancy and severe sepsis

: ICU patients with haematological malignancy have an increased risk of bleeding. Recently, global haemostatic methods such as thromboelastography (TEG) have gained impact in evaluating coagulation. The aim of this study was to observe whether TEG could predict bleeding in haematological ICU patients with severe sepsis. Post-hoc single-centre analysis of patients with haematological malignancy included in the Scandinavian Starch for Severe Sepsis/Septic Shock (6S) trial. Clinical characteristics, TEG measurements and details regarding bleeding complications were retrieved from the 6S database. The association between TEG and bleeding were analysed by Cox regression and receiver operating characteristic curves. A total of 202 patients with severe sepsis were admitted to the ICU of Rigshospitalet, Copenhagen and included in the 6S trial. Forty-one had haematological malignancy and were analysed in the current study. During ICU stay, 20 patients (49%) had bleeding complications and 13 (32%) patients bled within the first 5 ICU days. We observed no associations between TEG and subsequent bleeding in Cox regression models. TEG variables at baseline had low predictive value for bleeding. Baseline TEG variables did not add value in identifying patients with high risk of bleeding in ICU patients with haematological malignancy and severe sepsis.

Is surgical volume still the most accurate indicator of blood usage in the United States?

BACKGROUND

Estimates of blood collection and use in the United States derived from the National Blood Collection and Utilization Survey (NBCUS) call for application of robust statistical methods in the analysis of survey data. Since 1993, annual inpatient surgical volume has been used as the main stratification variable for sampling and estimation. However, recent NBCUS results have shown a decrease in blood use in surgical settings, raising the possibility that inpatient surgical volume may no longer be the optimal stratification variable. The objective of this study is to explore factors affecting hospital blood utilization.

STUDY DESIGN AND METHODS

A multivariate generalized linear regression with a negative binomial distribution was used to determine which hospital characteristics best explained allogeneic red blood cell (RBC) use, using data from the 2015 NBCUS to determine hospital blood use and the 2013 annual American Hospital Association database to identify hospital characteristics.

RESULTS

Annual inpatient surgical volume explained the most variation in allogeneic RBC use among hospitals (pseudo-R² of 70.8%). Additional variables, such as presence of an oncology service, were also statistically significant in the models but explained little additional variability in blood use.

CONCLUSION

These findings suggest that annual inpatient surgical volume is an appropriate indicator for estimating blood utilization in the United States. As trends in blood utilization continue to evolve, ongoing analytic efforts to understand indicators of blood use are necessary.

Thrombin generation in patients with severe thermal injury

BACKGROUND

Severe burns can induce a hypercoagulable state which is not depicted in conventional coagulation assays. The thrombin generation assay allows global assessment of coagulation and can identify hypercoagulability. We report changes in thrombin generation in patients after severe burn injury.

METHODS

We measured TGA, rotational thrombelastometry and conventional assays in 20 consecutive patients with a total body surface area burned of >20% over a 2-week period: the day after burn trauma (A), the morning after surgical excision of burn wounds (B) and on post-admission days 7 (C) and 14 (D).

RESULTS

Thrombin generation assay showed a procoagulatory state: there was an increase in the velocity of thrombin generation (increase in time to peak of +13%, increase in velocity index of +22%), and peak amount of thrombin (+25%) between days A and B. All parameters reached their highest levels on day C and returned towards normal on day D. Rotational thrombelastometry showed a hypercoagulable state with an increase in clot firmness and alpha angle. Conventional coagulation tests remained within reference values.

CONCLUSIONS

In the first two weeks following burn, both the thrombin generation assay and rotational thrombelastometry show a hypercoagulable state, while conventional coagulation tests remain normal.

Common haemostasis issues in major bleeding and critical illness

Haemostatic abnormalities are common in the critically ill or bleeding patient, including haemorrhage-related coagulopathies, disseminated intravascular coagulation and thrombocytopenia, among other pathologies. In this article we aim to outline some of the causes of these clotting abnormalities, highlighting recent advancements in knowledge and new insights into their clinical management, with the aim of optimising diagnostic and therapeutic strategies.

Transfusion of Fresh Frozen Plasma in Critically Ill Patients: Effective or Useless?

BACKGROUND

Fresh frozen plasma (FFP) is widely used in critically ill patients to correct the deficiency of coagulation factors or increased INR.

AIM

In the present study we aimed to evaluate the outcome of the freshly frozen plasma use as prophylaxis in ICU patients before an invasive procedure.

METHODS

The study was conducted at Central Anaesthesiology and Intensive Care Service UHCT "Mother Theresa", Tirana. 136 patients were enrolled with coagulopathy with no bleeding before the invasive procedure, from June 2016 to December 2016. A group of 75 patients underwent a median volume of 12.5 ml/kg FFP given, and 61 had no transfusion. Data were collected on demographics, the severity of illness measured by APACHE III scores, INR, medication use, hemodynamic data.

RESULTS

From 136 patients with coagulopathy with no bleeding who underwent planned invasive interventions, 75 [55%] received FFP, vs 61 [45%] p = 0.04 who did not receive. Overall, the median FFP dose was 12.5 ml kg-1. Median INR level in FFP and non-FFP groups was respectively 3.1 (1.9-4.8) and 3.5 (1.8-5.2). INR was corrected in 24 of 75 (32%) of those who received a transfusion. The frequency of minor bleeding episodes was 9.3% in transfused patients vs 4.9% in the non-transfused group. Patients who developed an onset of acute lung injury were more frequent in the FFP group. No allergic transfusion complications were observed. Also, the median length of hospital stay [LOS] was 3.05 days vs 2.91 days and mortality rate 8.2% vs 6.5% with no significant difference between two groups.

CONCLUSIONS

Freshly frozen plasma transfusions are often unnecessarily administered during an inadequate correction of the deficiencies of coagulation factors. When comparing a liberal FFP transfusion strategy vs restrictive other clinical trials are required to asses which one is the best to adopt in intensive care settings.

Retrospective Study of the Characteristics of Anticoagulant-Type Rodenticide Poisoning in Hong Kong

INTRODUCTION

Warfarin- and superwarfarin-type anticoagulants are commonly used as rodenticides. Exposure to these agents, especially superwarfarins with long-acting anticoagulant effect, can cause life-threatening coagulopathy in humans. Most superwarfarin poisoning cases had an obvious history of exposure, though occult cases without exposure history have also been reported. The current study aims to examine anticoagulant-type rodenticide poisoning in Hong Kong and to identify the similarities and differences between patients with known exposure history and those whose exposure is recognized only through laboratory testing.

METHODS

The present study was conducted in a tertiary referral clinical toxicology laboratory in Hong Kong. This was a retrospective cohort study of all patients with biochemically confirmed anticoagulant-type rodenticide exposure, from 2010 to 2014.

RESULTS

Superwarfarin was the most common group of anticoagulant-type rodenticides identified (87.8%), in which bromadiolone and brodifacoum were the most frequently encountered. Among the 41 cases identified, 31 had an obvious exposure history, and 10 were occult poisoning in which the context of exposure remained unidentified. All occult poisoning patients without exposure history presented with bleeding events. These occult poisoning cases often went unrecognized by frontline clinicians, leading to delayed investigation and initiation of treatment. This group of patients was associated with a longer time to diagnose coagulopathy (p < 0.001) and confirm rodenticide poisoning (p < 0.05), a higher rate of international normalized ratio (INR) rebound after initiation of antidote (p < 0.001), and a longer time needed for normalizing INR (p < 0.05).

CONCLUSION

Occult superwarfarin poisoning is an important yet under-recognized differential cause of unexplained coagulopathy. A high index of clinical suspicion and availability of specialized toxicological test for superwarfarins play a vital role in diagnosis and early initiation of appropriate management. The underlying cause of such poisoning remains obscure and warrants further study.

Clinical bleeding and thrombin generation in admissions to critical care with prolonged prothrombin time: an exploratory study

BACKGROUND

Prolongation of prothrombin time (PT) is often recorded in critical illness, but has limited ability to predict risk of bleeding. This exploratory study was aimed at assessing a role for thrombin generation (TG) to predict bleeding.

STUDY DESIGN AND METHODS

TG was measured by calibrated automated thrombography in admissions to intensive care with prolonged PT. Bleeding events were recorded up to Day 5 after enrollment and correlated with results of PT ratio (PTR) and variables of TG.

RESULTS

A total of 306 patients were recruited. A total of 101 bleeding events developed in 46 patients during the period of observation. Many patients with prolonged PT had endogenous thrombin potential (ETP), which was within the normal range (120/251 patients, 47.8%) or even elevated (8%). Although some patients had a reduction in ETP or peak thrombin, these were present over a wide range of PTR. There was no suggestion by receiver operating characteristic analysis that variables of conventional TG were sensitive at predicting bleeding. No bleeding events were documented in patients defined as ETP high, despite elevated PTR.

CONCLUSION

Future studies need to explore a role for alternatives tests of coagulation in critical illness. Development of TG assays is required to positively identify more patients at increased bleeding risk or to exclude a larger number at low risk and how this relates to subgroups, such as patients with liver disease, and the need for prophylactic plasma transfusion.

Changes in colloid solution sales in Nordic countries

BACKGROUND

Administration of resuscitation fluid is a common intervention in the treatment of critically ill patients, but the right choice of fluid is still a matter of debate. Changes in medical practice are based on new evidence and guidelines as well as traditions and personal preferences. Official warnings against the use of hydroxyl-ethyl-starch (HES) solutions have been issued. Nordic guidelines have issued several strong recommendations favouring crystalloids over colloids in all patient groups. Our objective was to describe the patterns of colloid use in Nordic countries from 2012 to 2016.

METHODS

The data were obtained from companies that provide pharmaceutical statistics in different countries. The data are sales figures from pharmaceutical companies to pharmacies and health institutions.

RESULTS

We found a 56% reduction in the total sales of all colloids in Nordic countries over a 5-year period. These findings were mainly related to a 92% reduction in the sales of HES solutions. A reduction in sales of other synthetic colloids has also occurred. During the same period, we found a 46% increase in albumin sales, but these numbers varied between Nordic countries.

CONCLUSION

The general reduction in colloid sales likely reflects the recommendation that colloids should be used only in special circumstances. The dramatic reduction in the sales of HES solutions was expected given evidence of harm and the official warnings. The steady increase in albumin sales and the notable differences between the five Nordic countries cannot be explained.

Evaluation of the circulating MicroRNA-495 and Stat3 as prognostic and predictive biomarkers for lower extremity deep venous thrombosis

This study aims to elucidate the prognostic and predictive biomarker of miR-495 and Stat3 in peripheral blood in relation to lower extremity deep venous thrombosis (DVT). Patients with lower limb fractures were assigned into case and control groups. Rats were allocated into blank (normal rats), sham (normal rats), DVT, miR-495 mimic, miR-495 inhibitor, over-Stat3, and si-Stat3 groups. ELISA was used to detect levels of prothrombin time (PT), endothelin-1 (ET-1), Human Fibrinogen (FIB), D-Dimer, blood coagulation factors V and VIII, tissue type plasminogen activator (t-PA), platelet activating factor (PAF), protein C and Stat3. qRT-PCR was employed for the evaluation of the expressions of miR-495 and Stat3, while receiver operating characteristic (ROC) curve was constructed to assess the predictive value of miR-495 and Stat3 as well as the treatment outcomes of patients with lower limb fractures. Logistic regression analyses were conducted in order to correlate indexes and lower extremity DVT. miR-495 overexpression, t-PA, PAF, and protein C were confirmed to be protective factors, while Stat3 overexpression, PT, ET-1, FIB, D-Dimer, blood coagulation factor V, and VIII were all ultimately considered to be risk factors of lower extremity DVT. Stat3 was confirmed to be the target gene of miR-495. Compared with the blank group, the length and weight of the thrombus as well as the ratio between length and weight, mRNA and protein expression of Stat3 were reduced in the miR-495 mimic and si-Stat3 groups. Our findings suggest that through the suppression of Stat3 expression, miR-495 prohibits lower extremity DVT in peripheral blood.

Retrospective Review of a Prothrombin Complex Concentrate (Beriplex P/N) for the Management of Perioperative Bleeding Unrelated to Oral Anticoagulation

A multicenter, retrospective, observational study of 4-factor prothrombin complex concentrate (PCC) and/or fresh frozen plasma (FFP) use within routine clinical care unrelated to vitamin K antagonists was conducted. The PCC was administered preprocedure for correction of coagulopathy (prophylactic cohort) and treatment of bleeding postsurgery (treatment cohort). Of the 445 patients included, 40 were in the prophylactic cohort (PCC alone [n = 16], PCC and FFP [n = 5], FFP alone [n = 19]) and 405 were in the treatment cohort (PCC alone [n = 228], PCC and FFP [n = 123], FFP alone [n = 54]). Cardiovascular surgery was the most common setting. PCC doses ranged between 500 and 5000 IU. Effectiveness (assessed retrospectively) was reported as effective in 93.0% in the PCC-only group (95% confidence interval, 89.1% to 95.9%), 78.9% (70.8% to 85.6%) with PCC and FFP, and 86.3% (76.2% to 93.2%) with FFP alone. In the treatment cohort, international normalized ratio was significantly reduced in all 3 groups. In patients who received PCC, the rate of thromboembolic events (1.9%) was below rates in the literature for similar procedures. PCCs offer a potential alternative to FFP in the management of perioperative bleeding unrelated to oral anticoagulant therapy.

Prediction of bleeding and thrombosis by standard biochemical coagulation variables in haematological intensive care patients

PURPOSE

We assessed the value of standard biochemical coagulation parameters in predicting bleeding, thrombosis and mortality in adult Intensive Care Unit (ICU) patients with haematological malignancies.

METHODS

We screened all patients with acute leukaemia and myelodysplastic syndrome admitted to a university hospital ICU during 2008-2012. Data were obtained from the clinical chemistry laboratory database and patient files. We graded bleeding according to the World Health Organisation (WHO)-system within 24-h, within 5-days and during the whole ICU stay. We analysed the predictive values of laboratory parameters using multiple logistic regression and receiver operator characteristics (ROC) curves. As we previously have established that platelet count at admission was associated with bleeding, we focused on International Normalised Ratio (INR), activated pro-thrombin time (APTT), anti-thrombin, D-dimer and fibrinogen, and markers of infection (C-reactive protein, pro-calcitonin), kidney function (creatinine) and tissue damage (lactate dehydrogenase (LDH)).

RESULTS

We included 116 patients; 66 (57%) had at least one bleeding episode and 11 (9%) patients had at least one thrombotic event. The differences in coagulation values when bleeding compared to baseline values were minor. INR was the only variable we found associated with subsequent bleeding within 24 h from admission to ICU (odds ratio 2.91, 95% CI: 1.01-8.43, P = 0.048). ROC analyses did not show predictive value of any of the other variables with regards to bleeding and none of the variables were associated with thrombosis in adjusted analyses. Increased levels of LDH at admission were associated with increased 7-day and 30-day mortality.

CONCLUSIONS

Increased INR at admission was associated with a higher rate of bleeding in ICU patients with haematological malignancies. No other biochemical coagulation or other parameter had any association with bleeding, thrombosis or mortality except increased LDH, which at ICU admission was associated with increased 30-day mortality.

Blood Product Administration in the Critical Care and Perioperative Settings

The critical care and perioperative settings are high consumers of blood products, with multiple units and different products often given to an individual patient. The recommendation of this review is always to consider the risks and benefits for a specific blood product for a specific patient in a specific clinical setting. Optimize patient status by treating anemia and preventing the need for red blood cell transfusion. Consider other options for correction of anemia and coagulation disorders and use an imperative non-overtransfusion policy for all blood products.

Plasma transfusions prior to lumbar punctures and epidural catheters for people with abnormal coagulation

BACKGROUND

The insertion of a lumbar puncture needle or epidural catheter may be associated with peri- and post-procedural bleeding. People who require this procedure may have disorders of coagulation as a result of their underlying illness, co-morbidities or the effects of treatment. Clinical practice in some institutions is to mitigate the risk of bleeding in these patients by prophylactically transfusing plasma in order to correct clotting factor deficiencies prior to the procedure. However, plasma transfusion is not without risk, and it remains unclear whether this intervention is associated with reduced rates of bleeding or other clinically-meaningful outcomes.

OBJECTIVES

To assess the effect of different prophylactic plasma transfusion regimens prior to insertion of a lumbar puncture needle or epidural catheter in people with abnormal coagulation.

SEARCH METHODS

We searched for randomised controlled trials (RCTs), non-randomised controlled trials (non-RCT) and controlled before-after studies (CBAs) in CENTRAL (the Cochrane Library 2016, Issue 11), MEDLINE (from 1946), Embase (from 1974), CINAHL (from 1937), the Transfusion Evidence Library (from 1950), and five other electronic databases as well as ClinicalTrials.gov and World Health Organization International Clinical Trials Registry Platform (ICTRP) for ongoing trials to 9 January 2017.

SELECTION CRITERIA

We planned to include RCTs, non-RCTs, and CBAs involving transfusions of plasma given to prevent bleeding in people of any age with a coagulopathy requiring insertion of a lumbar puncture needle or epidural catheter. If identified, we would have excluded uncontrolled studies, cross-sectional studies and case-control studies. We would only have included cluster-RCTs, non-randomised cluster trials, and CBAs with at least two intervention sites and two control sites. In studies with only one intervention or control site, the intervention (or comparison) is completely confounded by study site making it difficult to attribute any observed differences to the intervention rather than to other site-specific variables.We planned to exclude people with haemophilia as they should be treated with the appropriate factor concentrate. We also planned to exclude people on warfarin as guidelines recommend the use of prothrombin complex concentrate for emergency reversal of warfarin.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We identified no completed or ongoing RCTs, non-RCTs, or CBAs.

AUTHORS' CONCLUSIONS

There is no evidence from RCTs, non-RCTs, and CBAs to determine whether plasma transfusions are required prior to insertion of a lumbar puncture needle or epidural catheter, and, if plasma transfusions are required, what is the degree of coagulopathy at which they should be given. We would need to design a study with at least 47,030 participants to be able to detect an increase in the number of people who had bleeding after lumbar puncture or epidural anaesthetic from 1 in 1000 to 2 in 1000.

Prophylactic plasma transfusion for patients undergoing non-cardiac surgery

This is a protocol for a Cochrane Review (Intervention). The objectives are as follows: To determine the clinical effectiveness and safety of prophylactic plasma transfusion for people with confirmed or presumed coagulopathy requiring non-cardiac surgery.

Real-Time Clinical Decision Support Decreases Inappropriate Plasma Transfusion

OBJECTIVES

To curtail inappropriate plasma transfusions, we instituted clinical decision support as an alert upon order entry if the patient's recent international normalized ratio (INR) was 1.7 or less.

METHODS

The alert was suppressed for massive transfusion and within operative or apheresis settings. The plasma order was automatically removed upon alert acceptance while clinical exception reasons allowed for continued transfusion. Alert impact was studied comparing a 7-month control period with a 4-month intervention period.

RESULTS

Monthly plasma utilization decreased 17.4%, from a mean ± SD of 3.40 ± 0.48 to 2.82 ± 0.6 plasma units per hundred patient days (95% confidence interval [CI] of difference, -0.1 to 1.3). Plasma transfused below an INR of 1.7 or less decreased from 47.6% to 41.6% (P = .0002; odds ratio, 0.78; 95% CI, 0.69-0.89). The alert recommendation was accepted 33% of the time while clinical exceptions were chosen in the remaining cases (active bleeding, 31%; other clinical indication, 33%; and apheresis, 2%). Alert acceptance rate varied significantly among different provider specialties.

CONCLUSIONS

Clinical decision support can help curtail inappropriate plasma use but needs to be part of a comprehensive strategy including audit and feedback for comprehensive, long-term changes.