神经外科老年手术患者围手术期凝血功能变化

背景 手术、老年及神经组织影响老年神经外科手术患者的凝血与纤溶的平衡.血栓弹力图全面监测围手术期凝血与纤溶的变化,有助于维持正常的凝血功能. 目的 就手术、老年及神经组织对凝血与纤溶的影响和止血机制新观念及凝血与纤溶检测新技术(血栓弹力图)进行综述. 内容 老年神经外科手术患者凝血功能紊乱,导致围手术期高凝状态,倾向于血栓栓塞.以细胞为基础的止血机制新观念更加准确地阐述了体内止血过程分子机制,同时也促进了临床应用血栓弹力图分析血小板、凝血因子、纤溶功能. 趋向 这项新技术的使用将能够有效地防止围手术期血栓的形成或出血的发生.     

Evaluation of the efficacy of a new generation of hemostatic collagen compresses. Results of a multicenter prospective study in visceral surgery and neurosurgery

The hemostatic potential, tolerance and handiness of a new generation of hemostatic sheets (Hemostagene) were compared with those of reference collagen sheets in a randomized parallel-group multicenter study. Both types of hemostatic sheets, issued from calf derm, have been evaluated in digestive and neurosurgical pathologies. The comparability of both groups (52 patients in the Hemostagene group A, 54 in the reference group B) has been verified on morphological data, coagulation records and hemostasis conditions. The time required to achieve hemostasis was slightly, yet not significantly, shorter in group A (3 min 27 sec) than with the reference sheet (4 min 10 sec). This new sheet was judged significantly handier than the reference sheet. Adherence to the gloves and instruments was very significantly (p less than 0.0001) more frequent in the reference group B than in the group A. Both collagen sheets have quite similar clinical, biological and immunological tolerances which confirms the literature data. So, this new sheet, together with an hemostasis at least as good as the one obtained with the reference sheet, brings a highly improved handiness.     

Efficacy of Endoscopic Pure Ethanol Injection Method for Gastrointestinal Ulcer Bleeding

We reviewed endoscopic hemostatic effects of the pure ethanol injection (PEI) method for reducting emergency operations and deaths due to gastroduodenal ulcer bleeding. During 17 years beginning in June 1979 in Tohoku University Hospital, 331 patients underwent endoscopic hemostasis by the PEI method. Initial hemostasis was successfully obtained in all cases. Rebleeding occurred in about 4% of the patients, and rehemostasis was obtained successfully in all of them. Complete hemostasis was obtained in 330 of 331 patients (99.7%) using the PEI method; there were no deaths. Only one patient required emergency operation after hemostasis because of repeated neogenetic bleeding complicated with a perforation and another because of an unidentifiable neogenetic ulcer bleeding located just above the Vater papilla. None required other endoscopic hemostasis or interventional radiology. Moreover, after introduction of “second-look” endoscopy, the rebleeding rate decreased to about 1% with PEI hemostasis. Based on these excellent hemostatic effects of the PEI method, we believe that a comparative study with other hemostatic methods is not needed.     

Hemostatic Step-by-Step Procedure to Control Presacral Bleeding During Laparoscopic Total Mesorectal Excision

Background  A new procedure of hemostasis during laparoscopic total mesorectal excision is described. Methods  In our surgical department, from January 2004 to December 2007, 128 patients underwent laparoscopic total mesorectal excision. Among them, 47 patients underwent laparoscopic anterior resection after preoperative radiotherapy, 68 patients underwent laparoscopic anterior resection without preoperative radiotherapy, and 13 patients underwent laparoscopic abdominal perineal amputation. Results  In seven laparoscopic rectal surgery cases, we encountered unstoppable presacral bleeding, not amenable by conventional hemostatic solutions. In these cases we applied a simple staging hemostatic procedure. We first performed local compression: tamponing with a small gauze or absorbable fabric hemostat. If bleeding did not stop, we localized an epiploic or omental scrap and excised it by using bipolar forceps and use it as a plug on the tip of a grasping forceps. This plug is then put on the bleeding source and monopolar coagulation is applied by electrified dissecting forceps through the interposed grasping forceps. If bleeding did not stop, we used a little scrap of bovine pericardium graft and tacked it to the bleeding site using endoscopic helicoidal protack. Conclusions  Our experience suggests that this hemostatic step-by-step procedure is a valid option to control persistent presacral hemorrhages.     

Use of thromboelastography in children on extracorporeal membrane oxygenation

IntroductionExtracorporeal membrane oxygenation (ECMO) profoundly impacts inflammatory and coagulation pathways, and strict monitoring is essential to guide therapeutic anticoagulation. Thromboelastography (TEG) offers a global evaluation of whole blood hemostatic system components and may be a valuable measurement of hemostatic function in these patients. There is a paucity of data correlating TEG parameters with standard measures of coagulation in heparinized pediatric patients.MethodsChildren on ECMO during a 10-year period were retrospectively reviewed. Standard measures of coagulation were matched to TEGs drawn within 30 min of each other.ResultsOut of 296 unique patients with 331 ECMO runs, 74.3% (n = 246) had at least one set of matched laboratory samples for a total of 2502 matched samples. The aPTT correlated with R-time (p<0.001). Platelets and fibrinogen correlated with α-angle (p<0.001). Fibrinogen (p<0.001) and platelets (p<0.001) were each associated with maximum amplitude (MA). 158 (47.7%) patients had at least one bleeding complication, and 100 (30.2%) had at least one thrombotic complication. Interestingly, a decreasing MA was associated with increased thrombotic complications (p<0.001).DiscussionTEG correlated well with traditional measures of hemostasis in pediatric ECMO patients. However, there was not a clear benefit of the TEG over these other measuresLevel of evidenceIII.     

Peripherally inserted central catheter placement in patients with coagulation disorders: A retrospective analysis

ObjectiveTo assess the safety of peripherally inserted central venous catheter (PICC) placement in patients with altered and uncorrected coagulation parameters or receiving antiplatelet therapy.Materials and methodsMedical charts of all patients with major primary and secondary hemostasis disorders, combined hemostasis disorders or on antiplatelet therapy and who had undergone non-tunneled PICC placement from December 2009 to December 2013, were retrospectively reviewed. A hemostatic disorder was defined as a platelet count (PC) ≤ 50 × 10⁹/L, an international normalized ratio (INR) ≥ 2, or an activated partial thromboplastin time (aPTT) ≥ 66 s, alone or in combination. Underlying hemostasis disorders were not corrected and antiplatelet therapy was not interrupted before PICC placement in any patient. 4, and 5-Fr single and dual lumen PICCs were used.ResultsA total of 378 PICCs were placed in 271 patients (180 men and 91 women; mean age = 62 ± 13.4 years; range, 18 – 93 years)) with coagulation disorders. Eighty-nine (23%) PICCs were placed in patients who were receiving antiplatelet therapy (aspirin, clopidogrel, rivaroxaban). Thrombocytopenia was noted in 269 PICC placements (71%). Among these patients, 23 had disseminated intravascular coagulation. Prolonged INR and aPTT were observed in 42 procedures (11.1%). PICC placement was achieved in all patients, with a mean number of 1.14 attempts. Peripheral venous access was obtained through the basilic and the brachial vein respectively in 295 (79.1%) and 83 (20.9%) of patients. The placements were performed by residents and fellows in 108 (28.5%) and 270 (71.5%) procedures, respectively. No early or late complications were reported after any procedure. No accidental puncture of the brachial artery occurred.ConclusionIn patients with severe primary and secondary hemostasis disorders, combined hemostasis disorders or on antiplatelet therapy, PICC placement is a feasible and safe procedure and does not require correction of coagulation parameters or discontinuation of antiplatelet therapy.     

Recombinant Factor VIIa for Life-Threatening Hemorrhage in Trauma Patients: Review of the Literature

Abstract The control of hemorrhage and coagulopathy is a vital component of trauma care, and failure to achieve hemostasis can contribute to mortality. Recombinant factor VIIa (rFVIIa) is a well-established therapy for bleeding episodes and surgical prophylaxis in hemophilia patients with inhibitors. However, there has been increasing utilization of rFVIIa in the treatment of trauma-related blood loss in patients without pre-existing coagulopathy. This paper reviews published experience in this area. Database searches identified 126 rFVIIa-treated trauma patients reported in 15 publications between November 1999 and November 2004. Ages ranged from 20 months to 88 years, and the majority of patients (68.7%) had suffered blunt injury. In most cases, rFVIIa was used as a salvage therapy when bleeding continued despite the appropriate application of available conventional hemostatic methods. Doses of rFVIIa varied widely (36–178 μg/kg), with patients receiving a single dose or multiple doses separated by an interval of 2–12 h. Efficacy of treatment (reduction in blood loss, transfusion requirements and mortality) was reported for 79.4% of subjects. Most publications also described shortening or normalization of coagulation parameters following rFVIIa administration. No non-thrombotic adverse events were noted in any patient, but five cases (4.0%) of thromboembolic events were recorded. Recently reported clinical trial data offer support to these anecdotal observations. In conclusion, data appear to support the utility of rFVIIa as an adjunctive therapy for the reduction of hemorrhage and transfusion requirements in trauma patients. However, further information relating to the use of rFVIIa in the trauma setting is required.     

Use of hemostatic forceps as a preoperative rescue therapy for bleeding peptic ulcers

Standard endoscopic management of bleeding peptic ulcers includes injection, thermal coagulation, or mechanical clipping. The use of hemostatic forceps has increased with the widespread use of endoscopic submucosal dissection to control bleeding. However, there are few reports on the use of hemostatic forceps to control bleeding peptic ulcers. From January to October 2010, four hundred twenty-seven patients received endoscopic therapy at our institution for bleeding peptic ulcers. In 5 patients hemostasis was achieved with hemostatic forceps as a rescue therapy after standard endoscopic therapy had failed. In 4 patients successful hemostasis was achieved, whereas 1 patient had to undergo emergency surgery. We found that hemostatic forceps are a useful alternative for the control of bleeding peptic ulcers after standard endoscopic treatment has failed. This treatment may help in avoiding the necessity of surgery. Further large-scale studies are required to confirm our observations.     

可吸收止血流体明胶在颈前路椎体次全切除减压融合术中的应用

目的:探究可吸收止血流体明胶在单节段颈前路椎体次全切除减压融合术(anterior discectomy fusion,ACCF)中的止血效果。方法:自2014年8月至2018年2月选取行单节段颈前路椎体次全切除减压融合术患者44例,分为两组:试验组22例,男10例,女12例,年龄(55.6±9.7)岁,术中用可吸收止血流体明胶止血;对照组22例,男11例,女11例,年龄(54.4±11.1)岁,术中采用传统止血方法止血。比较两组手术时间、椎管减压所需时间、术中出血量、术后负压引流量、术后神经功能改善率、术后骨融合时间、术后钛网沉降率、术后血肿发生以及其他术后不良事件并发症。结果:试验组手术时间(83.1±19.2)min,明显少于对照组的(89.5±17.0)min(P<0.05);两组椎管减压时间分别为(52.4±13.7)、(56.1±14.6)min,差异有统计学意义(P=0.001);两组术中出血量分别为(49.9±12.4)、(90.6±36.7)ml,差异有统计学意义(P<0.05);两组术后负压引流球内引流总量分别为(42.5±18.3)、(60.0±22.8)ml,差异有统计学意义(P<0.05);两组术后1周神经功能改善率差异无统计学意义,术后3、6个月试验组比对照组有更好神经功能改善率。两组术后6个月均获得骨性融合,术后3个月均未发现明显钛网沉降,均无出现急性血肿、脑脊液漏及其他术后并发症。结论:可吸收止血流体明胶在ACCF手术中止血效果显著,可保持良好的手术术野,可减少椎管减压时间,减少术中出血量术后引流量,是一种较传统止血方法更有效且安全的止血材料。     

血液凝固:止血与凝血酶调节

围手术期出血是一个棘手的问题,尤其是伴随着强效抗凝药物临床应用的日趋增多,这一问题变得更具挑战性.理解和掌握当今的凝血概念对于手术前确定患者围手术期的出血风险并在围手术期给予有效的止血治疗十分重要.具有丝氨酸蛋白酶活性的凝血酶在激活其他丝氨酸蛋白酶原(无活性的酶前体)、辅助因子和细胞表面受体的过程中发挥着关键的作用.机...     

Activation of the hemostatic system during cardiopulmonary bypass

Cardiopulmonary bypass (CPB) is a unique clinical scenario that results in widespread activation of the hemostatic system. However, surgery also results in normal increases in coagulation activation, platelet activation, and fibrinolysis that are associated with normal wound hemostasis. Conventional CPB interferes with normal hemostasis by diluting hemostatic cells and proteins, through reinfusion of shed blood, and through activation on the bypass circuit surface of multiple systems including platelets, the kallikrein-kinin system, and fibrinolysis. CPB activation of the kallikrein-kinin system increases activated factor XIIa, kallikrein, bradykinin, and tissue plasminogen activator levels, but has little effect on thrombin generation. Increased tissue plasminogen activator and circulating fibrin result in increased plasmin generation, which removes hemostatic fibrin. The nonendothelial surface of the bypass circuit, along with circulating thrombin and plasmin, lead to platelet activation, platelet receptor loss, and reduced platelet response to wounds. In this review, we highlight the major mechanisms responsible for CPB-induced activation of the hemostatic system and examine some of the markers described in the literature. Additionally, strategies used to reduce this activation are discussed, including limiting cardiotomy suction, increasing circuit biocompatibility, antithrombin supplementation, and antifibrinolytic use. Determining which patients will most benefit from specific therapies will ultimately require investigation into genetic phenotypes of coagulation protein expression. Until that time, however, a combination of approaches to reduce the hemostatic activation from CPB seems warranted.     

Comparison of Ligasure Hemorrhoidectomy with Conventional Ferguson’s Hemorrhoidectomy

Conventional hemorrhoidectomy for grade III and IV hemorrhoids is a tedious procedure associated with significant morbidity and a prolonged convalescence. We compared Ligasure™ hemorrhoidectomy with conventional ‘closed’ Ferguson’s hemorrhoidectomy for the treatment of grade III and IV hemorrhoids. Forty-eight consecutive patients of grade III and IV hemorrhoids were randomized to either the Ligasure™ hemorrhoidectomy (28 patients) or Ferguson’s hemorrhoidectomy (20 patients). The hemorrhoidal predicle was coagulated with Ligasure™ in the Ligasure™ group and transfied with 2/0 chromic catgut in Ferguson’s method. In comparison with Ferguson’s method, Ligasure™ hemorrhoidectomy had a shorter operating time (29 vs 12.5 min), less blood loss (22 vs 11.5 ml), less post operative pain as measured on VAS scale and less postoperative complications including hemorrhage (10% vs 3.5%), urinary retention (10% vs 3.5%) and wound breakdown (20% vs 14%). The submucosal dissection technique with Ligasure™ coagulation of the hemorrhoidal pedicle is safe and effective. The blood vessels and tissue are reduced to a wafer thin seal with good hemostasis. Suturing is not required as the mucosal tissue over the pedicle is sealed off with the current. There is minimal lateral spread of either thermal or electrical energy. The external components of the hemorrhoids can also be treated at the same time. Because of its ease of use and less postoperative pain and complication Ligasure™ hemorrhoidectomy can be preformed as a day-care procedure.     

Monopolar electrocautery, an alternative novel method of hemostasis during radical cystectomy: Preliminary report

Objective  During radical cystectomy, local hemostasis is a critical factor for surgical success. It can be accomplished with a variety of techniques including mechanical compression, ligatures, cauterization and laser. The aim of this work was to evaluate monopolar electrocautery alone for achieving hemostasis during radical cystectomy. Patients and Methods  In this prospective study 30 patients were scheduled for radical cystectomy over a period of 2 years at Al-Azhar University Hospitals using monopolar electrocautery as the only hemostatie tool. The parameters studied were: operative time, estimated blood loss and incidence of complications. The data were analyzed clinically and statistically. Results  Monopolar electrocautery as the only hemostatic tool during radical cystectomy resulted in a short operative time (35±5 minutes). The mean estimated blood loss was 150±50 ml. Intraoperative bleeding was encountered in 2 patients only and they received blood transfusion. The overall post-operative early (within the first month) complication rate was low (13.3%) and all complications were managed conservatively. Conclusion  Monopolar electrocauterization is a safe method for achieving hemostasis during radical cystectomy, with a significantly short operative time, low cost, low blood loss, a low cystectomy-related complication rate and a short hospital stay.     

Lessons from the aprotinin saga: current perspective on antifibrinolytic therapy in cardiac surgery

Antifibrinolytic agents have been prophylactically administered to patients undergoing cardiopulmonary bypass (CPB) to reduce postoperative bleeding due to plasmin-mediated coagulation disturbances. After the recent market withdrawal of aprotinin, a potent bovine-derived plasmin inhibitor, two lysine analogs, ε-aminocaproic acid and tranexamic acid are currently available for clinical use. Although the use of aprotinin recently raised major concerns about postoperative thrombosis and organ dysfunctions, there is a paucity of information on the potential complications related to lysine analogs. Using the available preclinical and clinical data, we present current perspectives on the hemostatic mechanism and potential harms of antifbirnolytic therapy related to cardiac surgery. Fibrin formation is the critical step for hemostasis at the site of vascular injury, and localized fibrinolytic activity counterbalances excess fibrin formation which might result in vascular occlusion. Inhibition of the endogenous fibrinolytic system may be associated with thrombotic complications in susceptible organs. It is thus important to understand CPB-related changes in endogenous fibrinolytic proteins (e.g., tissue plasminogen activator (tPA), plasminogen) and antifibrinolytic proteins (e.g., α₂-antiplasmin).     

Invitro efficacy of RiaSTAP after rapid reconstitution

Background

Fibrinogen is the first coagulation factor to reach critical levels during hemorrhage. Consequently, reestablishing normal fibrinogen levels is necessary to achieve adequate hemostasis. Fibrinogen is supplemented through administration of fresh frozen plasma, cryoprecipitate, or human fibrinogen concentrate, RiaSTAP. RiaSTAP is potentially the most advantageous fibrinogen replacement product because it offers the highest fibrinogen concentration, lowest volume, and most consistent dose. Unfortunately, RiaSTAP is limited by a protocol reconstitution time of 15 min. Conversely, physicians in emergency settings frequently resort to a forceful and rapid reconstitution, which causes foaming and possible protein loss and/or damage. This study aims to address the in vitro effectiveness of protocol-reconstituted RiaSTAP versus rapidly reconstituted RiaSTAP versus cryoprecipitate.

Methods

Three fibrinogen treatments were prepared: protocol-reconstituted RiaSTAP, rapidly reconstituted RiaSTAP, and thawed cryoprecipitate. Each treatment was added in theoretical doses of 0–600 mg/dL to fibrinogen-depleted plasma (normal fibrinogen level is 150–450 mg/dL). Samples were generated in triplicate, and each sample was subjected to rapid thrombelastography and Clauss assays. The rapid thrombelastography assay measures the hemostatic potential of a blood and/or plasma sample. The maximum amplitude (MA) parameter indicates overall clot strength and is a reflection of fibrinogen efficacy. The Clauss assay measures the time to clot formation in response to a known concentration of thrombin, and the amount of functional fibrinogen is then determined from a standard curve.

Results

For all fibrinogen treatments, increasing fibrinogen dose resulted in an increase in MA. There was no significant difference in MA between both RiaSTAP reconstitutions (slope of RiaSTAP [protocol], 10.85 mm/[100 mg/dL] and slope of RiaSTAP [rapid], 10.54 mm/[100 mg/dL]). However, both protocol-reconstituted RiaSTAP and rapidly reconstituted RiaSTAP have higher MA values than cryoprecipitate in doses of ≥100 mg/dL. Moreover, each replicate of cryoprecipitate showed a higher variance in fibrinogen efficacy (coefficient of variance [CV] = 44.7%) at a fibrinogen dose of 300 mg/dL. RiaSTAP, however, showed a lower variance in fibrinogen efficacy for both reconstitutions (RiaSTAP [protocol], CV = 3.3% and RiaSTAP [rapid], CV = 2.7%), indicating a consistent fibrinogen dose.

Conclusions

RiaSTAP (either reconstitution method) has greater hemostatic potential and less variability in fibrinogen concentration compared with cryoprecipitate. Rapidly reconstituted RiaSTAP does not compromise hemostatic potential and can be used to potentially facilitate hemostasis in rapidly bleeding patients.     

Determination of efficacy of a novel alginate dressing in a lethal arterial injury model in swine

IntroductionAlginate is a biocompatible polysaccharide that is commonly used in the pharmaceutical, biomedical, cosmetic, and food industries. Though solid dressings composed of alginate can absorb water and promote wound healing, they are not effective hemostatic materials, particularly against massive hemorrhage. The purpose of this study is to attempt to increase the hemostatic capabilities of alginate by means of hydrophobic modification. Previous studies have illustrated that modifying a different polysaccharide, chitosan, in this way enhances its hemostatic efficacy as well as its adhesion to tissue. Here, it was hypothesized that modifying alginate with hydrophobic groups would demonstrate analogous effects.MethodsFifteen Yorkshire swine were randomized to receive hydrophobically-modified (hm) alginate lyophilized sponges (n = 5), unmodified alginate lyophilized sponges (n = 5), or standard Kerlix™ gauze dressing (n = 5) for hemostatic control. Following a splenectomy, arterial puncture (6 mm punch) of the femoral artery was made. Wounds were allowed to freely bleed for 30 s, at which time dressings were applied and compressed for 3 min in a randomized fashion. Fluid resuscitation was given to preserve the baseline mean arterial pressure. Wounds were monitored for 180 min after arterial puncture, and surviving animals were euthanized.ResultsBlood loss for the hm-alginate group was significantly less than the two control groups of (1) alginate and (2) Kerlix™ gauze (p = < 0.0001). Furthermore, 80% of hm-alginate sponges were able to sustain hemostasis for the full 180 min, whereas 0% of dressings from the control groups were able to achieve initial hemostasis.ConclusionsHm-alginate demonstrates a greatly superior efficacy, relative to unmodified alginate and Kerlix™ gauze dressings, in achieving hemostasis from a lethal femoral artery puncture in swine. This is a similar result as has been previously described when performing hydrophobic modification to chitosan. The current study further suggests that hydrophobic modification of a hydrophilic biopolymer backbone can significantly increase the hemostatic capabilities relative to the native biopolymer.     

Hematologic causes of intracerebral hemorrhage and their treatment.

Spontaneous ICH is an unusual and potentially disastrous event that may complicate primary and secondary hemostatic abnormalities. Among the primary abnormalities, deficiencies of coagulation factors I, VII, VIII, IX and XIII as well as von Willebrand factor have been clearly associated with ICH. Specific factor replacement or supportive management to normalize the hemostatic defect is indicated in each case. Among secondary alterations in hemostasis, thrombocytopenia, platelet function abnormalities, or factor consumption contribute to the risk of ICH in patients with ITP, TTP, disseminated intravascular coagulation, myeloproliferative or myelodysplastic disorders, and exposure to certain medications. The precise incidence of spontaneous hemorrhage among these disorders is unknown but low. Platelet transfusion and fibrinogen replacement are appropriate in specific cases; however, treatment of the underlying cause is usually required. The association of hemorrhage with antithrombotic agents in several settings is better defined. Cessation of the medication is required in each instance. Fibrinogen replacement may be required after the use of fibrinolytic agents. In all cases, an assessment of the precise hemostatic defect is recommended.     

The influence of induced hypothermia for hemostatic function on temperature-adjusted measurements in rabbits

In hypothermic patients, a tendency to bleed may be observed even when hemostatic tests seem to be normal. Coagulation and platelet function tests are usually performed at 37 degrees C. We investigated the influence of induced hypothermia on temperature-adjusted hemostasis function testing using Sonoclot Analyzer (Sonoclot) and Thromboelastography (TEG). Anesthesia was induced and maintained with IV ketamine and fentanyl on 15 male New-Zealand White rabbits. A water blanket was used to induce hypothermia to 30 degrees C and to rewarm to 37 degrees C. Blood samples were obtained at four points: before hypothermia, at 34 degrees C, at 30 degrees C, and after rewarming. Standard coagulation tests were performed at 37 degrees C (C method), and simultaneously, real temperature hemostasis function tests (R method) were run. In Sonoclot(R), activated clotting time and time to peak increased and clot rate decreased significantly at 30 degrees C in the R method compared with those in the C method. In TEG(R), reaction time and clot formation time were prolonged and clot formation rate was diminished at 30 degrees C in the R method compared with those in the C method. Induced hypothermia delayed the coagulation cascade and reduced platelet function. During hypothermia, hemostatic measurements should be performed at real temperature to avoid overestimating patient hemostatic function based on results measured at the standard 37 degrees C. IMPLICATIONS: We investigated the influence of induced hypothermia on temperature-adjusted hemostasis function tests in rabbits using Sonoclot Analyzer and Thromboelastography. Induced hypothermia delayed the coagulation cascade and reduced platelet function. The conventional coagulation tests performed at 37 degrees C failed to detect these hypothermia-induced degradations in hemostasis performance.     

On-site coagulation monitoring does not affect hemostatic outcome after cardiac surgery

BACKGROUND: Rapid coagulation tests are now available for monitoring of bleeding patients after cardiac surgery. As inappropriate blood use in these patients may be due to lack of timely coagulation data, we studied the effect of an algorithm with on-line coagulation monitoring on transfusions in these patients. METHODS: Prospectively, patients bleeding (>1.5 ml kg(-1) 15 min(-1)) after cardiac surgery were randomly assigned to two groups: in group A (n=28), hemostatic treatment during the immediate recovery period (1 h after surgery) was based on an algorithm with on-site hemostasis monitoring, whereas during the same period group B patients (n=30) were managed solely according to the clinician's judgement; laboratory tests other than activated clotting time after heparin neutralization were prohibited. RESULTS: Cumulative chest tube drainage up to 16 h and total transfusion requirements did not differ between the groups. Using a platelet transfusion trigger of 100x10(9)/l, significantly more patients received platelets during the immediate recovery period in the algorithm group than in the control group (14 vs. 3 patients, P=0.001). Desmopressin acetate was administered more often in group A than in group B (8 vs. 2 patients, P=0.04). CONCLUSIONS: Algorithm-based therapy increased utilization of hemostatic interventions during the immediate recovery period without any obvious benefit to the hemostatic outcome. Re-evaluation of the platelet transfusion trigger seems warranted.     

Massive transfusion and coagulopathy: pathophysiology and implications for clinical management

PURPOSE: To review the pathophysiology of coagulopathy in massively transfused, adult and previously hemostatically competent patients in both elective surgical and trauma settings, and to recommend the most appropriate treatment strategies. METHODS: Medline was searched for articles on "massive transfusion," "transfusion," "trauma," "surgery," "coagulopathy" and "hemostatic defects." A group of experts reviewed the findings. Principal findings: Coagulopathy will result from hemodilution, hypothermia, the use of fractionated blood products and disseminated intravascular coagulation. The clinical significance of the effects of hydroxyethyl starch solutions on hemostasis remains unclear. Maintaining a normal body temperature is a first-line, effective strategy to improve hemostasis during massive transfusion. Red cells play an important role in coagulation and hematocrits higher than 30% may be required to sustain hemostasis. In elective surgery patients, a decrease in fibrinogen concentration is observed initially while thrombocytopenia is a late occurrence. In trauma patients, tissue trauma, shock, tissue anoxia and hypothermia contribute to the development of disseminated intravascular coagulation and microvascular bleeding. The use of platelets and/or fresh frozen plasma should depend on clinical judgment as well as the results of coagulation testing and should be used mainly to treat a clinical coagulopathy. CONCLUSIONS: Coagulopathy associated with massive transfusion remains an important clinical problem. It is an intricate, multifactorial and multicellular event. Treatment strategies include the maintenance of adequate tissue perfusion, the correction of hypothermia and anemia, and the use of hemostatic blood products to correct microvascular bleeding.