Thromboelastographic Changes Research Articles

In vitro effects of lactated Ringer's solution, hypertonic saline, hydroxyethyl starch, hypertonic saline/hydroxyethyl starch, and mannitol on thromboelastographic variables of canine whole blood.

To assess the in vitro effects of crystalloid and colloid IV fluids on the thromboelastographic (TEG) variables of canine whole blood. In vitro experimental study. Veterinary teaching hospital. Twenty-two healthy dogs. Citrated whole blood samples collected from healthy dogs were diluted with 3.4% hypertonic saline (HTS 3.4), 7% hypertonic saline (HTS 7), and 20% mannitol at 8% and 16% dilutions; hydroxyethyl starch 130/0.4 (HES 130/0.4) at 16% dilution; lactated Ringer's solution (LRS) at 16%, 33%, and 66% dilutions; and HTS 7-HES 130/0.4 at 25% and 50% dilutions. Kaolin-activated TEG analysis was concurrently performed on diluted and control (undiluted) samples. Dilution of canine whole blood with LRS compared to control reduced α angle and MA at both 33% (P = 0.009 and P = 0.011, respectively) and 66% dilution (P<0.001 and P<0.001, respectively), and prolonged K time at 66% dilution (P = 0.003). At 16% dilution, HTS 3.4, prolonged R time (P = 0.007), while mannitol, a fluid iso osmolar to HTS 3.4, prolonged K time (P = 0.006), reduced α angle (P<0.001), MA (P = 0.046), and LY60 (P = 0.015). At 8% dilution, HTS 7, a fluid of high osmolarity and tonicity, prolonged R time (P = 0.009) and reduced MA (P = 0.015), while all measured TEG variables were altered at the 16% dilution (P<0.01 for all variables). HES 130/0.4 reduced α angle (P = 0.031) and MA (P = 0.001) and increased LY60 (P<0.001) at 16% dilution. Comparing different fluid types, HES 130/0.4 and HTS 3.4 had no to minor, mannitol intermediate, and HTS 7 profound effects on TEG variables (P<0.05) when compared to LRS at the same dilution. In vitro dilution of canine whole blood with commonly used IV fluids leads to thromboelastographic changes consistent with hypocoagulability in a dose dependent manner for all fluid types tested. Viscoelastic changes are also influenced by fluid characteristics, specifically tonicity and osmolarity.

Thromboelastographic changes during laparoscopic fundoplication.

IntroductionThromboelastography (TEG) is a technique that measures coagulation processes and surveys the properties of a viscoelastic blood clot, from its formation to lysis.AimTo determine the possible hypercoagulability state and the effect of antithrombotic prophylaxis on thromboelastogram results and development of venous thrombosis during laparoscopic fundoplication.Material and methodsThe study was performed on 106 patients who were randomized into two groups. The first group received low-molecular-weight heparin (LMWH) 12 h before the operation, and 6 and 30 h after it. The second group received LMWH only 1 h before the laparoscopic fundoplication. The TEG profile was collected before LMWH injection, 1 h after the introduction of the laparoscope and 15 min after the surgery was completed.ResultsThere was no significant difference in thromboelastography R-time between the groups before low-molecular-weight heparin injection. In group I preoperative R-values significantly decreased 1 h after the introduction of the laparoscope, after the end of surgery and on the third postoperative day. K-time values decreased significantly on the third postoperative day compared with the results before low-molecular-weight heparin injection, and after the operation. In group II, preoperative R-values significantly decreased 1 h after the introduction of the laparoscope, and after surgery. K-time values did not change significantly during or after the laparoscopic operation.ConclusionsOur study results demonstrated that the hypercoagulation state (according to the TEG results) was observed during and after laparoscopic fundoplication in patients when LMWH was administered 12 h before the operation together with intraoperative intermittent pneumatic compression. The optimal anticoagulation was obtained when LMWH was administered 1 h before fundoplication.

Thromboelastography in healthy dairy cows

Thromboelastography is a whole blood-based coagulation assay that can be used to investigate hypocoagulability and hypercoagulability, as seen with thromboembolic diseases and disseminated intravascular coagulation. Numerous coagulopathies due to different causes are reported in cows. The objective was to establish reference intervals for thromboelastography using the TEG 5000 (Haemonetics GmbH, Munich, Germany) with citrated whole blood samples and kaolin activation in dairy cows and to investigate possible thromboelastographic changes between cows in different lactation periods. An additional objective was to test the stability of samples for up to 100h. Sixty blood samples from healthy Holstein-Friesian cows were examined. The samples were allocated to 3 different lactation groups (≤30 d postcalving, 31–99 d postcalving, ≥100 d postcalving). Thromboelastography was performed by using the TEG 5000 analyzer with citrated whole blood samples with kaolin activation. The calculated reference intervals were as follows: reaction time=2.2 to 6.2min, coagulation time=0.8 to 2.0min, angle α=58.2 to 81.8°, maximum amplitude=64.3 to 89.2mm, and clot rigidity=9.2 to 41.2 dyn/cm2. The 3 different lactation groups showed no significant differences in TEG parameters. No significant difference was seen in samples stored for up to 48h at room temperature, which indicates that delays in processing samples, such as those arising during transit, are not an issue.

Thromboelastographic Changes in Patients Experiencing an Acute Ischemic Stroke and Receiving Alteplase

Thromboelastography is a method of measuring whole-blood coagulation changes and has been used to guide therapy and monitor changes in a variety of disease states. However, few studies have investigated the thromboelastographic changes experienced in a patient who has received alteplase for an acute ischemic stroke. This pilot study sought to describe the effect of alteplase on the thromboelastogram tracings of patients experiencing an acute ischemic stroke. This was an institutional review board-approved prospective cohort study. Patients who presented to the emergency department with symptoms of acute ischemic stroke and received intravenous alteplase were evaluated for inclusion. Blood samples were obtained before alteplase administration and at 30, 60, 90, 120, and 150minutes after alteplase administration. In addition, baseline variables collected included patient age, sex, prothrombin time, partial thromboplastin time, and the use of pretreatment anticoagulants or antiplatelet agents. Patients were also followed throughout their hospital stay for development of intracranial hemorrhage. A total of 7 patients were included in the analysis. At baseline, thromboelastogram parameters of all patients were within the normal range. The maximum inhibition of fibrin buildup was seen at 30minutes after the start of alteplase infusion, and the lowest clot strength was observed at 60minutes after initiation of alteplase. Most patients return to near baseline parameters within 150minutes of alteplase initiation; however, 2 patients did not return to their baseline values within the 150-minute time frame. Our study suggests that thromboelastogram (TEG) is a useful tool for determining changes in the coagulation system of patients whom have received recombinant tissue plasminogen activator (rt-PA). Further study is needed to determine if TEG can be used to predict those patients who may be at higher risk of adverse events because of rt-PA.

Thromboelastographic changes after gonadectomy in retired racing greyhounds

Twenty-one healthy greyhounds with no history or clinical signs of bleeding disorders, and no abnormalities on physical examination, complete blood count, serum biochemistry profiles (in dogs more than five years...

Thromboelastographic changes in liver and pancreatic cancer surgery: hypercoagulability, hypocoagulability or normocoagulability?

Despite clinical and laboratory evidence of perioperative hypercoagulability, alterations in haemostasis after potentially haemorrhagic oncologic surgery are difficult to predict. This study aims to evaluate the entity, the extent and the duration of perioperative coagulative alterations following pancreas and liver oncologic surgery, by the use of both routine tests and thromboelastogram (TEG). Fifty-six patients undergoing liver (n = 38) and pancreatic (n = 18) surgery were studied. The coagulation profile was evaluated by platelet count, prothrombin time-international normalized ratio, activated partial thromboplastin time, antithrombin III and TEG at the beginning, at the end of the operation and on postoperative days 1, 3, 5 and 10. All preoperative coagulative screening and TEG traces were normal before incision. In the postoperative period of the liver and pancreas groups, despite an increase in prothrombin time-international normalized ratio, a reduction in antithrombin III and platelet count and normal activated partial thromboplastin time and fibrinogen, TEG evidenced a normocoagulability in the liver group, with a major tendency towards hypocoagulability in the pancreas group, as evidenced by a transient increase in R-time and K-time between postoperative days 1 and 3. During the study period, four cases of pulmonary embolism, resolved with heparin infusion, were recorded, in the absence of laboratory and thromboelastographic evidence of hypercoagulability. Despite laboratory tests evidencing hypocoagulability in both groups, TEG traces showed a normocoagulability in liver resections, whereas a transient thromboelastographic hypocoagulability was evident in patients undergoing pancreas surgery. The discrepancy between laboratory values and thromboelastographic variables was even more evident in patients undergoing major liver resections compared with minor ones. Our study supports the role of thromboelastography, despite its limitations, as a valuable tool for the evaluation of the perioperative whole coagulation process and hypercoagulability changes and to increase patient safety through better management of antithrombotic therapy.

Thromboelastographic Changes Following Nonionic Contrast Medium Injection During Transfemoral Angiography in Patients with Peripheral Arterial Occlusive Disease

Patients with peripheral arterial occlusive disease (PAOD) are known to be systemically hypercoagulable and there is concern that exposing them to contrast media during angiography may exacerbate that thrombotic tendency. Many in vitro studies in which blood is exposed to contrast media suggest that nonionic contrast medium (NICM) has a weaker anticoagulant effect than ionic contrast medium (ICM) and some studies suggest that NICM can lead to activation of coagulation thus increasing the risk of thrombotic events where it is employed. We have looked at the changes in coagulation adjacent to the site of contrast injection/potential angioplasty to determine the magnitude of change locally. We measured changes in the coagulability of aortic blood samples immediately before and within 2 min after injection of the last bolus of iohexol (NICM) prior to any intervention procedure in 30 patients with PAOD. Samples were analyzed using thromboelastography (TEG) to identify changes in the coagulability of the aortic blood samples. TEG tracings of samples taken from the aorta after injection of NICM showed a significant increase in R time (time to fibrin formation) (p = 0.036) and in k time (dynamics of clot formation) (p = 0.028) and a reduction in Angle (decreased acceleration of fibrin build-up) (p = 0.013), Maximal amplitude (MA) (reduced ultimate clot strength) (p = 0.018) and Coagulation Index (CI) (p = 0.032). These changes in TEG parameters show that the local effect of NICM is a reduction in coagulation activity rather than the activation suggested by some previous studies.

Room H, 10/17/2000 9: 00 AM - 11: 00 AM (PS) Thromboelastographic Changes after Modified Ultrafiltration in Pediatric Cardiac Surgical Patients

<b>Room H, 10/17/2000 9: 00 AM - 11: 00 AM (PS) Thromboelastographic Changes after Modified Ultrafiltration in Pediatric Cardiac Surgical Patients</b>

A136 Thromboelastographic Changes Following 6% Hetastarch Administration for the Treatment of Perioperative Hypovolemia

A136 Thromboelastographic Changes Following 6% Hetastarch Administration for the Treatment of Perioperative Hypovolemia

Thromboelastographic Changes in Healthy Parturients and Postpartum Women

Thromboelastographic Changes in Healthy Parturients and Postpartum Women

Thromboelastographic changes in healthy parturients and postpartum women.

Thromboelastography (TEG) using disposable plastic cups and pins was performed with native whole blood (native group) in 17 nonpregnant volunteers, 134 healthy term pregnant women (>36 wk gestation), and 69 postpartum women. Thromboelastography was also performed with celite-activated whole blood (celite group) in 15 nonpregnant female volunteers, 38 healthy term pregnant women, and 34 postpartum women. The thromboelastographic parameters r and K were significantly decreased in pregnant and postpartum women compared with nonpregnant women in both groups (P < 0.05). The maximum amplitude MA, elastic shear modulus, and alpha angles were significantly increased in pregnant and postpartum women compared with nonpregnant women in both groups (P < 0.05). The TEG coagulation index was significantly greater in pregnant and postpartum women compared with nonpregnant women in both groups. In this study, TEG showed that pregnancy is a hypercoagulable state and that postpartum women remain hypercoagulable through the first 24 h postdelivery. The use of celite in TEG accelerated the speed of TEG analysis.

Ketorolac and Platelet Function

To the Editor: In an interesting study, Thwaites et al. [1] conclude that intravenous ketorolac given during general anesthesia and surgery does not alter platelet function and show that platelet function is insignificantly accelerated during knee arthroscopy. Although the surgical sympathetic response may predispose to platelet activation and hypercoagulability [2], it is intuitively related to the degree of surgical stress, with previous thromboelastographic changes found only during major abdominal and orthopedic surgery [3]. Two questions are raised. 1) Does sampling up to 45 min postadministration adequately reflect ketorolac's effect on platelets? As the mechanism of ketorolac's action is inhibition of phospholipase, surely the effect on existing platelets would not be apparent 45 min after administration? Would later measurements (considering the drug's half-life of 5 h) [4] not be more representative of platelet effects? 2) Is the stimulus of knee arthroscopy an adequate model to draw conclusions about platelet function during general anesthesia and surgery? In the absence of documentation of the dose or time of administration of anesthetic agents or the measurement of catecholamine levels, is this model adequately representative of the surgical stress response? It is quite possible that large doses of fentanyl or isoflurane might attenuate this minimal stimulus. Evan G. Pivalizza, MBChB, FFA David C. Abramson, MBChB, FFA Department of Anesthesiology University of Texas Medical School Houston, TX 77030

The Hemostatic Defect of Liver Disease

Excessive hemorrhage is not uncommon in liver disease and laboratory tests of hemostasis are frequently abnormal. Significant hypofibrinogenemia is rare. Hyperfibrinogenemia may occur in hepatocellular disease and is usual in tumors involving the liver and in obstructive jaundice. In hepatocellular disease, levels of factors II, V, VII, IX, X, XI, and XIII are frequently subnormal while factor VIII activity remains unchanged. Factors II, VII, and X may also be diminished in tumors of the liver and obstructive jaundice whereas factors V and VIII tend to be increased. Factor XIII activity may also be subnormal in tumors of the liver but is usually normal in obstructive jaundice. Excessive fibrinolysis has frequently been observed in cirrhosis of the liver. Quantitative and qualitative platelet defects also occur, as does consumption coagulopathy due to intravascular coagulation. Circulating anticoagulants have occasionally been described and increased capillary fragility has been demonstrated. Thromboelastographic changes are common in diseases of the liver and biliary system, reflecting changes in levels of coagulation factors and probably platelet function. Excessive hemorrhage in liver disease is probably due to a combination of the above factors rather than to a single abnormality. The clinical implications are discussed.