Current intraoperative storage and handling practices of autologous bypass conduit: A survey of the royal australasian college of surgeons.

During bypass surgery for peripheral arterial occlusive disease and ischaemic heart disease, autologous graft conduit including great saphenous veins and radial arteries are frequently stored in solution. Endothelial damage adversely affects the performance and patency of autologous bypass grafts, and intraoperative graft storage solutions have been shown to influence this process. The distribution of storage solutions currently used amongst Cardiothoracic and Vascular Surgeons from Australia and New Zealand is not well defined in the literature. The aim of this study was to determine current practices regarding autologous graft storage and handling amongst this cohort of surgeons, and discuss their potential relevance in the context of early graft failure. From this survey, the most frequently used storage solutions were heparinized saline for great saphenous veins, and pH-buffered solutions for radial arteries. Duration of storage was 30-45 min for almost half of respondents, although responses to this question were limited. Further research is required to investigate whether ischaemic endothelial injury generates a prothrombotic state, whether different storage media can alter this state, and whether this is directly associated with clinical outcomes of interest such as early graft failure.

Brain stem death induces pro-inflammatory cytokine production and cardiac dysfunction in sheep model.

INTRODUCTION: Organs procured following brain stem death (BSD) are the main source of organ grafts for transplantation. However, BSD is associated with inflammatory responses that may damage the organ and affect both the quantity and quality of organs available for transplant. Therefore, we aimed to investigate plasma and bronchoalveolar lavage (BAL) pro-inflammatory cytokine profiles and cardiovascular physiology in a clinically relevant 6-h ovine model of BSD. METHODS: Twelve healthy female sheep (37-42 Kg) were anaesthetized and mechanically ventilated prior to undergoing BSD induction and then monitored for 6 h. Plasma and BAL endothelin-1 and cytokines (IL-1ß, 6, 8 and tumour necrosis factor alpha (TNF-α)) were assessed by ELISA. Differential white blood cell counts were performed. Cardiac function during BSD was also examined using echocardiography, and cardiac biomarkers (A-type natriuretic peptide and troponin I were measured in plasma. RESULTS: Plasma concentrations big ET-1, IL-6, IL-8, TNF-α and BAL IL-8 were significantly (p < 0.01) increased over baseline at 6 h post-BSD. Increased numbers of neutrophils were observed in the whole blood (3.1 × 109 cells/L [95% confidence interval (CI) 2.06-4.14] vs. 6 × 109 cells/L [95%CI 3.92-7.97]; p < 0.01) and BAL (4.5 × 109 cells/L [95%CI 0.41-9.41] vs. 26 [95%CI 12.29-39.80]; p = 0.03) after 6 h of BSD induction vs baseline. A significant increase in ANP production (20.28 pM [95%CI 16.18-24.37] vs. 78.68 pM [95%CI 53.16-104.21]; p < 0.0001) and cTnI release (0.039 ng/mL vs. 4.26 [95%CI 2.69-5.83] ng/mL; p < 0.0001), associated with a significant reduction in heart contractile function, were observed between baseline and 6 h. CONCLUSIONS: BSD induced systemic pro-inflammatory responses, characterized by increased neutrophil infiltration and cytokine production in the circulation and BAL fluid, and associated with reduced heart contractile function in ovine model of BSD.

Randomised controlled trial of oxygen therapy and high-flow nasal therapy in African children with pneumonia.

PURPOSE: The life-saving role of oxygen therapy in African children with severe pneumonia is not yet established. METHODS: The open-label fractional-factorial COAST trial randomised eligible Ugandan and Kenyan children aged > 28 days with severe pneumonia and severe hypoxaemia stratum (SpO2 < 80%) to high-flow nasal therapy (HFNT) or low-flow oxygen (LFO: standard care) and hypoxaemia stratum (SpO2 80-91%) to HFNT or LFO (liberal strategies) or permissive hypoxaemia (ratio 1:1:2). Children with cyanotic heart disease, chronic lung disease or > 3 h receipt of oxygen were excluded. The primary endpoint was 48 h mortality; secondary endpoints included mortality or neurocognitive sequelae at 28 days. RESULTS: The trial was stopped early after enrolling 1852/4200 children, including 388 in the severe hypoxaemia stratum (median 7 months; median SpO2 75%) randomised to HFNT (n = 194) or LFO (n = 194) and 1454 in the hypoxaemia stratum (median 9 months; median SpO2 88%) randomised to HFNT (n = 363) vs LFO (n = 364) vs permissive hypoxaemia (n = 727). Per-protocol 15% of patients in the permissive hypoxaemia group received oxygen (when SpO2 < 80%). In the severe hypoxaemia stratum, 48-h mortality was 9.3% for HFNT vs. 13.4% for LFO groups. In the hypoxaemia stratum, 48-h mortality was 1.1% for HFNT vs. 2.5% LFO and 1.4% for permissive hypoxaemia. In the hypoxaemia stratum, adjusted odds ratio for 48-h mortality in liberal vs permissive comparison was 1.16 (0.49-2.74; p = 0.73); HFNT vs LFO comparison was 0.60 (0.33-1.06; p = 0.08). Strata-specific 28 day mortality rates were, respectively: 18.6, 23.4 and 3.3, 4.1, 3.9%. Neurocognitive sequelae were rare. CONCLUSIONS: Respiratory support with HFNT showing potential benefit should prompt further trials.

Endothelin receptor antagonist improves donor lung function in an ex vivo perfusion system.

BACKGROUND: A lung transplant is the last resort treatment for many patients with advanced lung disease. The majority of donated lungs come from donors following brain death (BD). The endothelin axis is upregulated in the blood and lung of the donor after BD resulting in systemic inflammation, lung damage and poor lung graft outcomes in the recipient. Tezosentan (endothelin receptor blocker) improves the pulmonary haemodynamic profile; however, it induces adverse effects on other organs at high doses. Application of ex vivo lung perfusion (EVLP) allows the development of organ-specific hormone resuscitation, to maximise and optimise the donor pool. Therefore, we investigate whether the combination of EVLP and tezosentan administration could improve the quality of donor lungs in a clinically relevant 6-h ovine model of brain stem death (BSD). METHODS: After 6 h of BSD, lungs obtained from 12 sheep were divided into two groups, control and tezosentan-treated group, and cannulated for EVLP. The lungs were monitored for 6 h and lung perfusate and tissue samples were processed and analysed. Blood gas variables were measured in perfusate samples as well as total proteins and pro-inflammatory biomarkers, IL-6 and IL-8. Lung tissues were collected at the end of EVLP experiments for histology analysis and wet-dry weight ratio (a measure of oedema). RESULTS: Our results showed a significant improvement in gas exchange [elevated partial pressure of oxygen (P = 0.02) and reduced partial pressure of carbon dioxide (P = 0.03)] in tezosentan-treated lungs compared to controls. However, the lungs hematoxylin-eosin staining histology results showed minimum lung injuries and there was no difference between both control and tezosentan-treated lungs. Similarly, IL-6 and IL-8 levels in lung perfusate showed no difference between control and tezosentan-treated lungs throughout the EVLP. Histological and tissue analysis showed a non-significant reduction in wet/dry weight ratio in tezosentan-treated lung tissues (P = 0.09) when compared to control. CONCLUSIONS: These data indicate that administration of tezosentan could improve pulmonary gas exchange during EVLP.

Considerations for Antiplatelet Management of Carotid Stenting in the Setting of Mechanical Thrombectomy: A Delphi Consensus Statement.

BACKGROUND AND PURPOSE: There are only few data and lack of consensus regarding antiplatelet management for carotid stent placement in the setting of endovascular stroke treatment. We aimed to develop a consensus-based algorithm for antiplatelet management in acute ischemic stroke patients undergoing endovascular treatment and simultaneous emergent carotid stent placement. MATERIALS AND METHODS: We performed a literature search and a modified Delphi approach used Web-based questionnaires that were sent in several iterations to an international multidisciplinary panel of 19 neurointerventionalists from 7 countries. The first round included open-ended questions and formed the basis for subsequent rounds, in which closed-ended questions were used. Participants continuously received feedback on the results from previous rounds. Consensus was defined as agreement of ≥70% for binary questions and agreement of ≥50% for questions with >2 answer options. The results of the Delphi process were then summarized in a draft manuscript that was circulated among the panel members for feedback. RESULTS: A total of 5 Delphi rounds were performed. Panel members preferred a single intravenous aspirin bolus or, in jurisdictions in which intravenous aspirin is not available, a glycoprotein IIb/IIIa receptor inhibitor as intraprocedural antiplatelet regimen and a combination therapy of oral aspirin and a P2Y12 inhibitor in the postprocedural period. There was no consensus on the role of platelet function testing in the postprocedural period. CONCLUSIONS: More and better data on antiplatelet management for carotid stent placement in the setting of endovascular treatment are urgently needed. Panel members preferred intravenous aspirin or, alternatively, a glycoprotein IIb/IIIa receptor inhibitor as an intraprocedural antiplatelet agent, followed by a dual oral regimen of aspirin and a P2Y12 inhibitor in the postprocedural period.

Antiplatelet Management for Stent-Assisted Coiling and Flow Diversion of Ruptured Intracranial Aneurysms: A DELPHI Consensus Statement.

BACKGROUND AND PURPOSE: There is a paucity of data regarding antiplatelet management strategies in the setting of stent-assisted coiling/flow diversion for ruptured intracranial aneurysms. This study aimed to identify current challenges in antiplatelet management during stent-assisted coiling/flow diversion for ruptured intracranial aneurysms and to outline possible antiplatelet management strategies. MATERIALS AND METHODS: The modified DELPHI approach with an on-line questionnaire was sent in several iterations to an international, multidisciplinary panel of 15 neurointerventionalists. The first round consisted of open-ended questions, followed by closed-ended questions in the subsequent rounds. Responses were analyzed in an anonymous fashion and summarized in the final manuscript draft. The statement received endorsement from the World Federation of Interventional and Therapeutic Neuroradiology, the Japanese Society for Neuroendovascular Therapy, and the Chinese Neurosurgical Society. RESULTS: Data were collected from December 9, 2019, to March 13, 2020. Panel members achieved consensus that platelet function testing may not be necessary and that antiplatelet management for stent-assisted coiling and flow diversion of ruptured intracranial aneurysms can follow the same principles. Preprocedural placement of a ventricular drain was thought to be beneficial in cases with a high risk of hydrocephalus. A periprocedural dual, intravenous, antiplatelet regimen with aspirin and a glycoprotein IIb/IIIa inhibitor was preferred as a standard approach. The panel agreed that intravenous medication can be converted to oral aspirin and an oral P2Y12 inhibitor within 24 hours after the procedure. CONCLUSIONS: More and better data on antiplatelet management of patients with ruptured intracranial aneurysms undergoing stent-assisted coiling or flow diversion are urgently needed. Panel members in this DELPHI consensus study preferred a periprocedural dual-antiplatelet regimen with aspirin and a glycoprotein IIb/IIIa inhibitor.

Acquired von Willebrand syndrome in respiratory extracorporeal life support: a systematic review of the literature.

BACKGROUND AND OBJECTIVE: Venovenous extracorporeal membrane oxygenation (VV ECMO) and extracorporeal CO2 removal (ECCO2R) are increasingly used in the management of severe respiratory failure. With bleeding complications being one of the major risks of these techniques, our aim in this systematic review was to assess the available literature on acquired von Willebrand syndrome (AvWS) and extracorporeal support. AvWS has previously been associated with bleeding and shear stress. DESIGN AND DATA SOURCES: A systematic review, using Medline via PubMed, was performed to identify eligible studies up to January 2017. RESULTS AND CONCLUSION: The prevalence of AvWF among patients on VV ECMO or ECCO2R is high, but only a limited number of studies are reported in the literature. AvWS testing should be performed, including vWF multimer analysis, vWF activity and vWF antigen concentration. The extent to which vWF contributes to bleeding during ECMO, or how much changes in ECMO management can influence high molecular weight vWF multimer levels, cannot be answered from the currently available evidence and there remains a need for future studies.

Neural network imaging to characterize brain injury in cardiac procedures: the emerging utility of connectomics.

Cognitive dysfunction is a poorly understood but potentially devastating complication of cardiac surgery. Clinically meaningful assessment of cognitive changes after surgery is problematic because of the absence of a means to obtain reproducible, objective, and quantitative measures of the neural disturbances that cause altered brain function. By using both structural and functional connectivity magnetic resonance imaging data to construct a map of the inter-regional connections within the brain, connectomics has the potential to increase the specificity and sensitivity of perioperative neurological assessment, permitting rational individualized assessment and improvement of surgical techniques.

Global tidal variations, regional distribution of ventilation, and the regional onset of filling determined by electrical impedance tomography: reproducibility.

The reproducibility of the regional distribution of ventilation and the timing of onset of regional filling as measured by electrical impedance tomography lacks evidence. This study investigated whether electrical impedance tomography measurements in healthy males were reproducible when electrodes were replaced between measurements. Part 1: Recordings of five volunteers lying supine were made using electrical impedance tomography and a pneumotachometer. Measurements were repeated at least three hours later. Skin marking ensured accurate replacement of electrodes. No stabilisation period was allowed. Part 2: Electrical impedance tomography recordings of ten volunteers; a 15 minute stabilisation period, extra skin markings, and time-averaging were incorporated to improve the reproducibility. Reproducibility was determined using the Bland-Altman method. To judge the transferability of the limits of agreement, a Pearson correlation was used for electrical impedance tomography tidal variation and tidal volume. Tidal variation was judged to be reproducible due to the significant correlation between tidal variation and tidal volume (r2 = 0.93). The ventilation distribution was not reproducible. A stabilisation period, extra skin markings and time-averaging did not improve the outcome. The timing of regional onset of filling was reproducible and could prove clinically valuable. The reproducibility of the tidal variation indicates that non-reproducibility of the ventilation distribution was probably a biological difference and not measurement error. Other causes of variability such as electrode placement variability or lack of stabilisation when accounted for did not improve the reproducibility of the ventilation distribution.

A 4-arm randomized controlled pilot trial of innovative solutions for jugular central venous access device securement in 221 cardiac surgical patients.

PURPOSE: To improve jugular central venous access device (CVAD) securement, prevent CVAD failure (composite: dislodgement, occlusion, breakage, local or bloodstream infection), and assess subsequent trial feasibility. MATERIALS AND METHODS: Study design was a 4-arm, parallel, randomized, controlled, nonblinded, pilot trial. Patients received CVAD securement with (i) suture+bordered polyurethane (suture + BPU; control), (ii) suture+absorbent dressing (suture + AD), (iii) sutureless securement device+simple polyurethane (SSD+SPU), or (iv) tissue adhesive+simple polyurethane (TA+SPU). Midtrial, due to safety, the TA+SPU intervention was replaced with a suture + TA+SPU group. RESULTS: A total of 221 patients were randomized with 2 postrandomization exclusions. Central venous access device failure was as follows: suture + BPU controls, 2 (4%) of 55 (0.52/1000 hours); suture + AD, 1 (2%) of 56 (0.26/1000 hours, P=.560); SSD+SPU, 4 (7%) of 55 (1.04/1000 hours, P=.417); TA+SPU, 4 (17%) of 23 (2.53/1000 hours, P=.049); and suture + TA+SPU, 0 (0%) of 30 (P=.263; intention-to-treat, log-rank tests). Central venous access device failure was predicted (P<.05) by baseline poor/fair skin integrity (hazard ratio, 9.8; 95% confidence interval, 1.2-79.9) or impaired mental state at CVAD removal (hazard ratio, 14.2; 95% confidence interval, 3.0-68.4). CONCLUSIONS: Jugular CVAD securement is challenging in postcardiac surgical patients who are coagulopathic and mobilized early. TA+SPU was ineffective for CVAD securement and is not recommended. Suture + TA+SPU appeared promising, with zero CVAD failure observed. Future trials should resolve uncertainty about the comparative effect of suture + TA+SPU, suture + AD, and SSD+SPU vs suture + BPU.

Nursing team leader handover in the intensive care unit contains diverse and inconsistent content: An observational study.

BACKGROUND: Despite a proliferation of evidence and the development of standardised tools to improve communication at handover, evidence to guide the handover of critical patient information between nursing team leaders in the intensive care unit is limited. OBJECTIVE: The study aim was to determine the content of information handed over during intensive care nursing team leader shift-to-shift handover. DESIGN: A prospective observational study. SETTING: A 21-bed medical/surgical adult intensive care unit specialising in cardiothoracic surgery at a tertiary referral hospital in Queensland, Australia. PARTICIPANTS: Senior nurses (Grade 5 and 6 Registered nurses) working in team leader roles, employed in the intensive care unit were sampled. METHOD: After obtaining consent from nursing staff, team leader handovers were audiotaped over 20 days. Audio recordings were transcribed and analysed using deductive and inductive content analysis. The frequency of content discussed at handover that fell within the a priori categories of the ISBAR schema (Identify-Situation-Background-Assessment-Recommendation) was calculated. RESULTS: Forty nursing team leader handovers were recorded resulting in 277 patient handovers and a median of 7 (IQR 2) patients discussed at each handover. The majority of nurses discussed the Identity (99%), Situation (96%) and Background (88%) of the patient, however Assessment (69%) content was varied and patient Recommendations (60%) were discussed less frequently. A diverse range of additional information was discussed that did not fit into the ISBAR schema. CONCLUSIONS: Despite universal acknowledgement of the importance of nursing team leader handover, there are no previous studies assessing its content. Study findings indicate that nursing team leader handovers contain diverse and inconsistent content, which could lead to inadequate handovers that compromise patient safety. Further work is required to develop structured handover processes for nursing team leader handovers.

Hydrodynamic evaluation of aortic cardiopulmonary bypass cannulae using particle image velocimetry.

The high velocity jet from aortic arterial cannulae used during cardiopulmonary bypass potentially causes a "sandblasting" injury to the aorta, increasing the possibility of embolisation of atheromatous plaque. We investigated a range of commonly available dispersion and non-dispersion cannulae, using particle image velocimetry. The maximum velocity of the exit jet was assessed 20 and 40 mm from the cannula tip at flow rates of 3 and 5 L/min. The dispersion cannulae had lower maximum velocities compared to the non-dispersion cannulae. Dispersion cannulae had fan-shaped exit profiles and maximum velocities ranged from 0.63 to 1.52 m/s when measured at 20 mm and 5 L/min. Non-dispersion cannulae had maximum velocities ranging from 1.52 to 3.06 m/s at 20 mm and 5 L/min, with corresponding narrow velocity profiles. This study highlights the importance of understanding the hydrodynamic performance of these cannulae as it may help in selecting the most appropriate cannula to minimize the risk of thromboembolic events or aortic injury.

Protocol guided bleeding management improves cardiac surgery patient outcomes.

BACKGROUND AND OBJECTIVES: Excessive bleeding is a risk associated with cardiac surgery. Treatment invariably requires transfusion of blood products; however, the transfusion itself may contribute to postoperative sequelae. Our objective was to analyse a quality initiative designed to provide an evidenced-based approach to bleeding management. MATERIALS AND METHODS: A retrospective analysis compared blood product transfusion and patient outcomes 15 months before and after implementation of a bleeding management protocol. The protocol incorporated point-of-care coagulation testing (POCCT) with ROTEM and Multiplate to diagnose the cause of bleeding and monitor treatment. RESULTS: Use of the protocol led to decreases in the incidence of transfusion of PRBCs (47·3% vs. 32·4%; P < 0·0001), FFP (26·9% vs. 7·3%; P < 0·0001) and platelets (36·1% vs. 13·5%; P < 0·0001). During the intra-operative period, the percentage of patients receiving cryoprecipitate increased (2·7% vs. 5·1%; P = 0·002), as did the number of units transfused (248 vs. 692; P < 0·0001). The proportion of patients who received tranexamic acid increased (13·7% to 68·2%; P < 0·0001). There were reductions in re-exploration for bleeding (5·6% vs. 3·4; P = 0·01), superficial chest wound (3·3% vs. 1·4%; P = 0·002), leg wound infection (4·6% vs. 2·0%; P < 0·0001) and a 12% reduction in mean length of stay from operation to discharge (95%: 9-16%, P < 0·0001). Acquisition cost of blood products decreased by $1 029 118 in the 15-month period with the protocol. CONCLUSIONS: The implementation of a bleeding management protocol supported by POCCT in a cardiac surgery programme was associated with significant reductions in the transfusion of allogeneic blood products, improved outcomes and reduced cost.

The time taken for the regional distribution of ventilation to stabilise: an investigation using electrical impedance tomography.

Electrical impedance tomography is a novel technology capable of quantifying ventilation distribution in the lung in real time during various therapeutic manoeuvres. The technique requires changes to the patient's position to place the electrical impedance tomography electrodes circumferentially around the thorax. The impact of these position changes on the time taken to stabilise the regional distribution of ventilation determined by electrical impedance tomography is unknown. This study aimed to determine the time taken for the regional distribution of ventilation determined by electrical impedance tomography to stabilise after changing position. Eight healthy, male volunteers were connected to electrical impedance tomography and a pneumotachometer. After 30 minutes stabilisation supine, participants were moved into 60 degrees Fowler's position and then returned to supine. Thirty minutes was spent in each position. Concurrent readings of ventilation distribution and tidal volumes were taken every five minutes. A mixed regression model with a random intercept was used to compare the positions and changes over time. The anterior-posterior distribution stabilised after ten minutes in Fowler's position and ten minutes after returning to supine. Left-right stabilisation was achieved after 15 minutes in Fowler's position and supine. A minimum of 15 minutes of stabilisation should be allowed for spontaneously breathing individuals when assessing ventilation distribution. This time allows stabilisation to occur in the anterior-posterior direction as well as the left-right direction.

Transfusion of packed red blood cells reduces selenium levels and increases lipid peroxidation in an in vivo ovine model.

BACKGROUND: Oxidative stress from surgery or critically illness has been shown to adversely contribute to morbidity and mortality. Recent studies record that oxidative stress is heightened following packed red blood cell (PRBC) transfusions and that products of oxidative stress accumulate as the PRBC ages. However, there are no studies that investigate if transfusion of aged PRBC actually increases the recipient's oxidative stress profile more than fresh PRBC. OBJECTIVE: To compare the effect of fresh vs aged PRBC transfusions on the recipient's oxidative stress using an ovine model. MATERIALS AND METHODS: Male sheep were transfused with either fresh (n = 6) or aged (n = 6) ovine PRBC, and serial blood samples taken. Plasma samples were analysed for lipid peroxidation using the thiobarbituric acid reactive substances (TBARS) assay. This served as an indicator of oxidative injury. Antioxidant function and trace element levels were also measured. RESULTS: Like human PRBC, the ovine PRBC had negligible selenium levels. Irrespective of age, PRBC transfusion was associated with reduced selenium levels and antioxidant function, which correlated with increased markers of lipid peroxidation. CONCLUSION: Transfusion of selenium poor PRBC can dilute selenium levels and compromise glutathione peroxidase antioxidant activity and thereby allow lipid peroxidation. As there was no evidence that aged PRBC induced more severe oxidative injury this suggests that selenium dilution is a key underlying mechanism. Further studies are needed to assess the impact of transfusion-related oxidative stress in massive transfusions.

Cardiac surgery in indigenous Australians: early onset cardiac disease with follow-up challenges.

OBJECTIVE: To review the risk factors, complications and follow-up of Indigenous patients post cardiac surgery. METHODS: This was a retrospective study of Indigenous patients who underwent cardiac surgery at an Australian tertiary hospital between 2002 and 2009. Patients' medical notes were reviewed and data collected and analysed. RESULTS: There were 220 Indigenous patients who had cardiac surgery. Non-elective surgery was performed in 45.0% (99/220). A history of smoking was reported by 76.8% (169/220). The most common operation was coronary artery bypass grafting with a mean age of 55 years. Of the 71 valve operations, 31.0% had rheumatic heart disease. Mechanical valves were given to 56.3% (40/71) of patients with a mean age of 45 years. The rate of peri-operative bleeding requiring blood transfusion or reoperation was 8.6% (19/220) and 28-day mortality was 0.45% (1/220). Of the patients with mechanical valves, 10.0% (4/40) did not present for outpatient review. Late anticoagulation related complications were haemorrhagic stroke 7.5% (3/40) and ischaemic bowel 2.5% (1/40). Late mortality was 9.5% (21/220). Late anticoagulation related deaths were in 1.8% (4/220), of whom 0.9% (2/220) had mechanical valves. CONCLUSIONS: The mean age of 52 years at which Indigenous patients have cardiac surgery is significantly low compared to non-Indigenous patients. Indigenous patients have multiple risk factors for cardiac disease and with a large number requiring emergency surgery. Although surgical outcome in the short term is favourable, a large number of patients are lost to follow-up. The use of mechanical valve and warfarin should be individualised. Strategic post-operative follow-up mechanisms are needed to address these issues.

Efficacy and safety of fibrinogen concentrate in trauma patients--a systematic review.

PURPOSE: Uncontrolled bleeding is the main preventable cause of death in severe trauma patients. Fibrinogen is the first coagulation factor to decrease during trauma-induced coagulopathy, suggesting that pharmacological replacement might assist early hemorrhage control. Several sources of fibrinogen are available; however, fibrinogen concentrate (FC) is not routinely used in trauma settings in most countries. The aim of this review is to summarize the available literature evaluating the use of FC in the management of severe trauma. METHODS: Studies reporting the administration of FC in trauma patients published between January 2000 and April 2013 were identified from MEDLINE and from the Cochrane Library. RESULTS: The systematic review identified 12 articles reporting FC usage in trauma patients: 4 case reports, 7 retrospective studies, and 1 prospective observational study. Three of these were not restricted to trauma patients. CONCLUSIONS: Despite methodological flaws, some of the available studies suggested that FC administration may be associated with a reduced blood product requirement. Randomized trials are warranted to determine whether FC improves outcomes in prehospital management of trauma patients or whether FC is superior to another source of fibrinogen in early hospital management of trauma patients.

A comprehensive ovine model of blood transfusion.

BACKGROUND: The growing awareness of transfusion-associated morbidity and mortality necessitates investigations into the underlying mechanisms. Small animals have been the dominant transfusion model but have associated limitations. This study aimed to develop a comprehensive large animal (ovine) model of transfusion encompassing: blood collection, processing and storage, compatibility testing right through to post-transfusion outcomes. MATERIALS AND METHODS: Two units of blood were collected from each of 12 adult male Merino sheep and processed into 24 ovine-packed red blood cell (PRBC) units. Baseline haematological parameters of ovine blood and PRBC cells were analysed. Biochemical changes in ovine PRBCs were characterized during the 42-day storage period. Immunological compatibility of the blood was confirmed with sera from potential recipient sheep, using a saline and albumin agglutination cross-match. Following confirmation of compatibility, each recipient sheep (n = 12) was transfused with two units of ovine PRBC. RESULTS: Procedures for collecting, processing, cross-matching and transfusing ovine blood were established. Although ovine red blood cells are smaller and higher in number, their mean cell haemoglobin concentration is similar to human red blood cells. Ovine PRBC showed improved storage properties in saline-adenine-glucose-mannitol (SAG-M) compared with previous human PRBC studies. Seventy-six compatibility tests were performed and 17·1% were incompatible. Only cross-match compatible ovine PRBC were transfused and no adverse reactions were observed. CONCLUSION: These findings demonstrate the utility of the ovine model for future blood transfusion studies and highlight the importance of compatibility testing in animal models involving homologous transfusions.

Stored blood transfusion induces transient pulmonary arterial hypertension without impairing coagulation in an ovine model of nontraumatic haemorrhage.

BACKGROUND AND OBJECTIVES: Transfusion of blood products in particular older products is associated with patient morbidity. Previously, we demonstrated a higher incidence of acute lung injury in lipopolysaccharide-treated sheep transfused with stored blood products. As transfusion following haemorrhage is more common, we aimed to determine whether a 'first hit' of isolated haemorrhage would precipitate similar detrimental effects following transfusion and also disrupt haemostasis. MATERIALS AND METHODS: Anaesthetized sheep had 33% of their total blood volume collected into Leukotrap bags (Pall Medical), which were processed into packed red blood cells and cross-matched for transfusion into other sheep. After 30 mins, the sheep were resuscitated with either: fresh (<5 days old) or stored (35-42 days old) ovine blood followed by 4% albumin to replacement volume, albumin alone or normal saline alone and monitored for 4 h. RESULTS: The first hit of haemorrhage precipitated substantial decreases in mean arterial pressure however haemostasis was preserved. Transfusion of stored ovine blood induced (1) transient pulmonary arterial hypertension but no oedema and (2) reduced fibrinogen levels more than fresh blood, but neither induced coagulopathy. Thus, transfusion of stored blood affected pulmonary function even in the absence of overt organ injury. CONCLUSION: The fact that stored blood transfusions: (1) did not induce acute lung injury in contrast to previous lipopolysaccharide-primed animal models identifies the 'first hit' as an important determinant of the severity of transfusion-mediated injury; (2) impaired pulmonary dynamics verifies the sensitivity and vulnerability of the pulmonary system to injury.