Patient blood management during the COVID-19 pandemic: a narrative review.

As COVID-19 disease escalates globally, optimising patient outcome during this catastrophic healthcare crisis is the number one priority. The principles of patient blood management are fundamental strategies to improve patient outcomes and should be given high priority in this crisis situation. The aim of this expert review is to provide clinicians and healthcare authorities with information regarding how to apply established principles of patient blood management during the COVID-19 pandemic. In particular, this review considers the impact of the COVID-19 pandemic on blood supply and specifies important aspects of donor management. We discuss how preventative and control measures implemented during the COVID-19 crisis could affect the prevalence of anaemia, and highlight issues regarding the diagnosis and treatment of anaemia in patients requiring elective or emergency surgery. In addition, we review aspects related to patient blood management of critically ill patients with known or suspected COVID-19, and discuss important alterations of the coagulation system in patients hospitalised due to COVID-19. Finally, we address special considerations pertaining to supply-demand and cost-benefit issues of patient blood management during the COVID-19 pandemic.

The association of pre-operative anaemia with survival after orthotopic liver transplantation.

Anaemia is common in patients with end-stage liver disease. Pre-operative anaemia is associated with greater mortality after major surgery. We analysed the association of pre-operative anaemia (World Health Organization classification) with survival and complications after orthotopic liver transplantation using Cox and logistic regression models. We included patients undergoing their first orthotopic liver transplantation between 2004 and 2016. Out of 599 included patients, 455 (76%) were anaemic before transplantation. Pre-operative anaemia was not associated with the survival of 485/599 (81%) patients to 1 year after liver transplantation, OR (95%CI) 1.04 (0.64-1.68), p = 0.88. Pre-operative anaemia was associated with higher rates of intra-operative blood transfusions and acute postoperative kidney injury on multivariable analysis, OR (95%CI) 1.70 (0.82-2.59) and 1.72 (1.11-2.67), respectively, p < 0.001 for both. Postoperative renal replacement therapy was associated with pre-operative anaemia on univariate analysis, OR (95%CI) 1.87 (1.11-3.15), p = 0.018.

Fast- and slow-exploring pigeons differ in how they use previously learned rules.

Several studies report a correlation between exploratory behaviour and performance on tests of cognitive ability. Exploration may influence learning because less exploratory animals are less likely to come in contact with to-be-learned stimuli. Alternatively, the way information available in the environment is processed could influence the rate of exploration. Pigeons are one of the most-studied species used to examine the mechanisms underlying cognitive abilities, but have not been used to examine the relationship between these abilities and animal personality. Here, twelve pigeons were first tested in a novel environment to assess repeatability in exploratory behaviour. Pigeons were then trained to discriminate between two visual stimuli: lines oriented at 90° (vertical, the S+) and 135° (the S-). After training pigeons underwent generalization testing with ten additional visual line orientation stimuli. We found exploratory behaviour was related to generalization performance: fast-explorers had steeper generalization gradients compared to slow-explorers. This effect was only seen in the direction towards the S-. These results suggest that birds with different exploratory styles differ in how they use previously learned information. Further testing is needed to confirm which cue(s) (S+ or S-) control the behaviour of fast-explorers.

Evaluation of clinical practice in perioperative patient blood management.

BACKGROUND: Several guidelines have been published to facilitate implementation of patient blood management (PBM). This study was performed to evaluate clinical practices in PBM. METHODS: An online survey based on the guidelines for the management of severe perioperative bleeding from the European Society of Anaesthesiology (ESA) was conducted among ESA members. We assessed characteristic data of participating physicians, preoperative assessment of bleeding risk and anaemia, intraoperative transfusion practices, specific pharmacologic treatment of significant bleeding, and clinical use of PBM algorithms. Data distributions for five European regions and the workplace and experience of physicians were analysed using a χ2 test. RESULTS: We received 706 fully completed surveys from physicians in 57 countries. Most (99%) respondents were anaesthetists or intensive care physicians, and 68% worked at university or university-affiliated hospitals. A standardised bleeding history before surgery is routinely obtained by 48% of physicians. When bleeding history is negative, 55% of physicians routinely order preoperative coagulation testing. Only 24% of physicians timely assess patients at risk of bleeding during surgery for anaemia before elective surgery. When anaemia is diagnosed, 38% of physicians routinely investigate its cause. The rate of routinely performed targeted haemostatic interventions with fibrinogen, vitamin K or prothrombin complex, and tranexamic acid was 60%, 52%, and 54%, respectively. Algorithms to guide PBM are used by 62% of physicians. Results varied between geographic regions. CONCLUSIONS: Major deficits exist in the use of recommended PBM among anaesthetists, indicating an opportunity to improve clinical standards.

Preoperative anaemia is associated with poor clinical outcome in non-cardiac surgery patients.

BACKGROUND: Retrospective studies suggest that preoperative anaemia is associated with poor outcomes after surgery. The objective of this study was to describe mortality rates and patterns of intensive care resource use for patients with anaemia undergoing non-cardiac and non-neurological in-patient surgery. METHODS: We performed a secondary analysis of a large prospective study describing perioperative care and survival in 28 European nations. Patients at least 16 yr old undergoing in-patient surgery during a 7 day period were included in the study. Data were collected for in-hospital mortality, duration of hospital stay, admission to intensive care, and intensive care resource use. Multivariable logistic regression analysis was performed to understand the effects of preoperative haemoglobin (Hb) levels on in-hospital mortality. RESULTS: We included 39 309 patients in the analysis. Preoperative anaemia had a high prevalence in both men and women (31.1% and 26.5%, respectively). Multivariate analysis showed that patients with severe [odds ratio 2.82 (95% confidence interval 2.06-3.85)] or moderate [1.99 (1.67-2.37)] anaemia had higher in-hospital mortality than those with normal preoperative Hb concentrations. Furthermore, hospital length of stay (P<0.001) and postoperative admission to intensive care (P<0.001) were greater in patients with anaemia than in those with normal Hb concentrations. CONCLUSIONS: Anaemia is common among non-cardiac and non-neurological surgical patients, and is associated with poor clinical outcome and increased healthcare resource use. CLINICAL TRIAL REGISTRATION: NCT01203605 (ClinicalTrials.gov).

Perioperative treatment algorithm for bleeding burn patients reduces allogeneic blood product requirements.

BACKGROUND: Surgical excision of burn wounds is often associated with severe bleeding. Timely and targeted correction of coagulopathy reduces transfusion requirements and improves survival in trauma victims. We hypothesized that rapid correction of coagulopathy after a treatment algorithm based on point-of-care viscoelastic coagulation testing would decrease allogeneic blood product transfusions during surgical excision of burn wounds. METHODS: Thirty consecutive patients undergoing surgical excision of burn wounds were enrolled into this prospective, randomized, controlled, single-centre study. In the control group, coagulation management was performed according to the clinicians' discretion. For the algorithm group, we standardized treatment based on the Austrian recommendation for the management of trauma-induced coagulopathy using point-of-care rotational thromboelastometry (ROTEM(®)). The main outcome parameter was the cumulative number of allogeneic blood units transfused on the day of surgery. RESULTS: The difference between the groups regarding the cumulative use of allogeneic blood products was highly significant with 3.0 (1.3-5.5) blood products in the algorithm group compared with 9.0 (6.0-12.3) in the control group [median (inter-quartile range); P=0.002]. No plasma was administered in the algorithm group compared with 5.0 (1.5-7.5) units overall in the control group (P<0.001). Fibrinogen concentrate administration was not significantly different between the groups (P=0.89). Tranexamic acid was not administered. CONCLUSIONS: The significant reduction in allogeneic blood product requirements during surgical burn wound excision is a prospective proof of concept that a bleeding management algorithm based on thromboelastometry is efficacious. Hypofibrinogenaemia and hyperfibrinolysis are not significant pathomechanisms of bleeding in this setting and ROTEM(®) helps to avoid unnecessary interventions.

Eosinophils are necessary for pulmonary arterial remodeling in a mouse model of eosinophilic inflammation-induced pulmonary hypertension.

There is increasing evidence that inflammation plays a pivotal role in the pathogenesis of some forms of pulmonary hypertension (PH). We recently demonstrated that deficiency of adiponectin (APN) in a mouse model of PH induced by eosinophilic inflammation increases pulmonary arterial remodeling, pulmonary pressures, and the accumulation of eosinophils in the lung. Based on these data, we hypothesized that APN deficiency exacerbates PH indirectly by increasing eosinophil recruitment. Herein, we examined the role of eosinophils in the development of inflammation-induced PH. Elimination of eosinophils in APN-deficient mice by treatment with anti-interleukin-5 antibody attenuated pulmonary arterial muscularization and PH. In addition, we observed that transgenic mice that are devoid of eosinophils also do not develop pulmonary arterial muscularization in eosinophilic inflammation-induced PH. To investigate the mechanism by which APN deficiency increased eosinophil accumulation in response to an allergic inflammatory stimulus, we measured expression levels of the eosinophil-specific chemokines in alveolar macrophages isolated from the lungs of mice with eosinophilic inflammation-induced PH. In these experiments, the levels of CCL11 and CCL24 were higher in macrophages isolated from APN-deficient mice than in macrophages from wild-type mice. Finally, we demonstrate that the extracts of eosinophil granules promoted the proliferation of pulmonary arterial smooth muscle cells in vitro. These data suggest that APN deficiency may exacerbate PH, in part, by increasing eosinophil recruitment into the lung and that eosinophils could play an important role in the pathogenesis of inflammation-induced PH. These results may have implications for the pathogenesis and treatment of PH caused by vascular inflammation.