Over the years, our hospital has been using Amicar… until there was a drug shortage. With that drug shortage came a different drug called tranexamic acid. We’ve been using it for awhile and I can’t seem to tell a difference in coagulation between the two drugs. Let’s break down each one and also discuss cost-effectiveness.
Tranexamic acid acts by reversibly blocking the lysine binding sites of plasminogen, thus preventing plasmin activation and, as a result, the lysis of polymerised fibrin.12 Tranexamic acid is frequently utilised to enhance haemostasis, particularly when fibrinolysis contributes to bleeding. In clinical practice, tranexamic acid has been used to treat menorrhagia, trauma-associated bleeding and to prevent perioperative bleeding associated with orthopaedic and cardiac surgery.13–16 Importantly, the use of tranexamic acid is not without adverse effects. Tranexamic acid has been associated with seizures,17 18 as well as concerns of possible increased thromboembolic events, including stroke which to date have not been demonstrated in randomised controlled trials.
Fibrinolysis is the mechanism of clot breakdown and involves a cascade of interactions between zymogens and enzymes that act in concert with clot formation to maintain blood flow.25 During extracorporeal circulation, such as cardiopulmonary bypass used in cardiac surgery, multiplex changes in haemostasis arise that include accelerated thrombin generation, platelet dysfunction and enhanced fibrinolysis.26 Tranexamic acid inhibits fibrinolysis, a putative mechanism of bleeding after cardiopulmonary bypass, by forming a reversible complex with plasminogen.
In summary, we found no evidence that tranexamic acid increases the risk of death and thrombotic complications after coronary-artery surgery. Tranexamic acid was associated with a lower risk of bleeding complications than placebo but also with a higher risk of postoperative seizures.
The study used a high-dose regimen, in which either 50 mg/kg or 100 mg/kg of TXA was delivered for each patient. There is a possibility that lower dose of TXA can be equally effective while causing less adverse effects. In fact, TXA plasma concentrations required to suppress fibrinolysis and plasmin-induced platelet activation are merely 10 and 16 μg/ml, respectively [7, 8]. This relatively low plasma concentration can be reached in cardiac surgery when 10 mg/kg of TXA is administered as a bolus then followed by continuous infusion of 1 mg kg/h and 1 mg/kg in CPB [9]. But another potential mechanism of TXA action might be the increase in thrombin formation, which requires concentrations more than 126 μg/ml to be effective [10, 11]. 30 mg/kg of TXA administered as a bolus followed by 16 mg/kg/h and 2 mg/kg in CPB prime solution was able to maintain the plasma concentration above 114 μg/ml [9].
Using their model-based meta-analysis, the authors conclude that low-dose tranexamic acid (total dose of 20 mg/kg of actual body weight) provides the best balance between reduction in postoperative blood loss and red blood cell transfusion and the risk of clinical seizure. The use of higher doses would only marginally improve the clinical effect at the cost of an increased risk of seizure.
Low-risk group received a single 50 mg/kg TXA bolus after induction of anesthesia. The high-risk group received Blood Conservation Using Anti-fibrinolytics Trial (BART) TXA regimen, consisting of 30 mg/kg bolus infused over 15 minutes after induction, followed by 16 mg/kg/h infusion until chest closure with a 2 mg/kg load within the pump prime.
Risk of seizure is dose-dependent, with the greatest risk at higher doses of tranexamic acid. We conclude that, in general, patients with a high risk of bleeding should receive high-dose tranexamic acid, while those at low risk of bleeding should receive low-dose tranexamic acid with consideration given to potential dose-related seizure risk. We recommend the regimens of high-dose (30 mg kg−1 bolus + 16 mg kg−1 h−1 + 2 mg kg−1 priming) and low-dose (10 mg kg−1 bolus + 1 mg kg−1 h−1 + 1 mg kg−1 priming) tranexamic acid, as these are well established in terms of safety profile and have the strongest evidence for efficacy.
The exposure value with the low-dose tranexamic acid regimen proposed by Horrow et al. (10 mg/kg followed by 1 mg/kg/h over 12 h) was close to the 80% effective concentration for postoperative blood loss and above the 80% effective concentration for erythrocyte transfusion. Compared to this regimen, a fivefold increase in total dose (100 mg/kg) achieved only a 58 ml (95% credible interval,54 to 65 ml) increment in the reduction of postoperative blood loss, up to 48 h postsurgery, with a decrease in erythrocyte transfusion rate from 46% to 44%.
Concentrations close to 80% effective concentration can be achieved at the end of surgery with a low-dose regimen administered either as a preoperative bolus plus infusion (10mg/kg followed by 1mg/kg/h) or as a single preoperative loading dose of 20mg/kg (fig. 6). Postoperative administration of tranexamic acid appears unnecessary because tranexamic acid concentrations will decrease but nevertheless remain sufficient (greater than or equal to EC50) up to the end of the drug’s contribution to blood loss reduction (8 h after the start of surgery).
The type of surgery and the duration of CPB both affected the risk of seizure. Open-chamber surgery resulted in a 5.5-fold increase in the risk of seizure compared to closed-chamber procedures (95% credible interval, 3.2 to 10). Each additional hour of CPB doubled the risk of seizure (2.0;95% credible interval, 1.2 to 3.2).
Ortho/Spine
OB
Trauma
Currently at our hospital (June 2022):
TXA DOSING AND ADMINISTRATION OVERVIEW
How supplied from Pharmacy
TXA 1000mg/10mL vials Will not provide premade bags like with Amicar; Amicar is a more complex mixture than TXA Will take feedback on this after go-live and reassess
There are a number of dosing strategies in the literature. What I recommend for maximal safety and efficacy is taken from Zuffery, et al. Anesthesiology 2021 meta-analysis and is practiced at Scripps Mercy.
~ 20 mg/kg total dose recommended in this meta-analysis.
Two dosing strategies they report that were as effective as high-dose but with lower seizure risk than high dose:
I found myself on the wrong side of the ether screen earlier this year, having surgery on my left hand to release Dupuytren’s contracture, a genetic gift from my father and (maybe) generations of our Viking forebears. Wondering how long it will take to heal – and when I’ll get some (any?) grip strength back […]
20-something year old primip came today with preeclampsia and was deemed a c/s candidate for her 26 week baby. She was 5’8″, 165lb and had no prior issue with previous surgeries. She was started on magnesium preop. The mag was held intraoperatively and would resume postoperatively. Pt was in sitting position for her spinal, which was placed at L4-5. Good clear CSF return. 0.75% bupi dosed at 13.5 mg with intrathecal fentanyl 15mcg and intrathecal morphine 0.2mg. BP decreased from 150s to 130s, which was appropriate. Patient stated she had increased tingling and decreased mobility in her legs. All symptoms and signs appropriate with her spinal. Patient passed the Allis clamp test prior to incision. She was quite anxious: propofol was given IV for anxiolysis. Patient was adamant about breastfeeding/pumping for her baby. No complications with delivery. Uterus was externalized and patient was sensitive to pressure and tugging/manipulation. IV fenatnyl and IV morphine were given along with IV propofol. When uterus was internalized, patient felt more pressure that seemed unbearable. More IV pain meds were given. Suggestion was made for intraperitoneal chloroprocaine. Patient able to tolerate fascial closure as well as staple skin closure.
Everyone has a role within their expertise. We can all work together as a team.
“Doctor” should be reserved for physicians who have earned that title and clinically trained as one.
Health care providers have a duty to honestly represent their roles to patients. Because “doctor” unambiguously means “physician” to patients, only physicians should introduce themselves to patients as “doctor.” Because “anesthesiologist” implies “physician,” only residency-trained physicians should adopt the term “anesthesiologist.”
With an opioid crisis at its peak, physicians need to be more cognizant of the various pain modalities available to patients. Gabapentinoids are one of the many non-opioid options to help with acute and chronic pain.
Myxoma is the most common primary benign cardiac tumor, which could lead to some fatal complications because of its strategic position. Although any age can be affected, it predominates in the age group of 30-60 years of age with more than 75% of the affected being women. The occurrence of myxomas in left and right atrium are 75% and 20% respectively.The majority of myxomas present with systemic emboli, fever and/or weight loss, or intracardiac obstruction to blood flow.1 A ‘tumor plop’ is a sound that typically occurs during early diastole and is believed to be caused by motion of the tumor striking the wall of the endocardium. The treatment is surgical excision and key aims of anesthesia care include constant monitoring of systemic blood pressure, adequate IV fluids, and judicious use of vasoactive medications to prevent a fall in systemic vascular resistance.3
Preop
A-line/CVP
Assess patient symptomatology: SOB, chest pain, changes in pulse pressure/CVP with positioning, heart sounds
Adequate PIV access
Vasopressors to help with SVR and heart rate control – mass can act as stenotic valve
Intraop
Induction: maintain SVR and consider slowing heart rate if mass blocking valves
Postop
2D TEE: X-plane
2D TEE: color flow through mitral valve
2D TEE: LA myxoma
2D TEE: LA myxoma w color
3D TEE: LA myxoma
From OpenAnaesthesia2D TEE: measurement of stalkResected myxoma
Sleepy Time 