2021 Traumatic ICU Deep Vein Thrombosis Prevention Strategy

2021 Traumatic ICU Deep Vein Thrombosis Prevention Strategy: Expert Consensus of the American Academy of Trauma Critical Care.

Does the severity of craniocerebral injury affect the timing and dosage of anticoagulants?

1. The timing of anticoagulation of VTE drugs to prevent traumatic brain injury

Recommendation: The initial prevention recommendation is 24-72 hours after admission, unless the patient’s intracranial hemorrhage has not stabilized or has indications for craniotomy.

Discussion: In the TBI population, about 54% of patients will have VTE without any form of prevention of VTE, and 20-30% of patients with mechanical prevention will have VTE. In a 2016 study of patients with craniocerebral trauma, the duration of anticoagulation was less than 72 hours than that of 72 hours. The incidence of PE and VTE in early anticoagulation was significantly less than that of patients with advanced anticoagulation, and there was no increase in the risk of cerebral hemorrhage. In another recent clinical study, patients with craniocerebral trauma were divided into four groups according to the anticoagulation strategy: <24 hours, 24–48 hours, >48 hours and no anticoagulation therapy. The study suggests that early anticoagulation does not increase cerebral hemorrhage Probability, the progression rate of cerebral hemorrhage in patients undergoing preventive anticoagulation was 14.1%. Another guideline pointed out that the best anticoagulation time for such patients is 24-72 hours, which does not increase the risk of intracranial hemorrhage.

2. Does the severity of craniocerebral injury affect the timing and dosage of anticoagulants?

Recommendation: The timing of anticoagulation should be individualized and affected by various factors, including the degree of traumatic brain injury.

Discussion: The Berne-Norwood standard indicates that in the absence of multiple brain contusions, patients with isolated subarachnoid/intraventricular hemorrhage and subdural/external hematoma ≤8mm, patients with stable head CT scan review 24 hours after injury can consider drugs Anticoagulant. Patients with medium-to-high risk VTE with a delay of more than 72 hours may need to consider preventive inferior vena cava filter placement. The most commonly used doses of unfractionated heparin (UFH) and low molecular weight heparin (LMWH) enoxaparin are 5000 units of Q8H and 30 mg of Q12H. Monitoring anti-Xa factors can be used to monitor bleeding risk and adjust dosage.

3. the choice of anticoagulant drugs for traumatic brain injury

Recommendation: Both unfractionated heparin and low molecular weight heparin can be used, and low molecular weight heparin is more recommended.

Discussion: The timing and type of anticoagulant used in patients with craniocerebral trauma are very important. Byrne et al. in the trauma database study found that compared with unfractionated heparin, low-molecular-weight heparin is more effective in preventing PE in severe trauma patients (1.4% vs 2.4%), and low-molecular-weight heparin does not increase unplanned brain injury in patients The incidence of surgery; although unfractionated heparin is currently less and less used in traumatic brain injury, heparin is selected for use in certain specific cases due to its short half-life. Low molecular weight heparin is convenient to use and more suitable for patients. Some new anticoagulants or aspirin have not been confirmed by relevant clinical studies to be suitable for use in patients with craniocerebral trauma, and they are indeed effective.

4. VTE anticoagulation strategy for substantial organ injury

Recommendation: In trauma patients with substantial organ injury, if there is no active bleeding or absolute anticoagulation contraindications, it is recommended to use low molecular weight heparin for anticoagulation within 48 hours after injury.

Discussion: Substantial organ damage includes liver, kidney, and spleen damage. In the process of implementing conservative treatment, determining the safe timing of anticoagulation is a clinical problem. We recommend that anticoagulation measures should be implemented as soon as possible after definitive hemostasis measures are implemented in trauma patients. However, in trauma patients undergoing conservative treatment, the trade-off between anticoagulation and bleeding requires constant attention. Therefore, in patients with substantial organ injury who confirm that there is no active bleeding, anticoagulation within 48 hours may be safe, and it will not increase the chance of bleeding and the need for emergency surgery. However, in patients with grade IV–V injury to the parenchymal organs, due to the high possibility of surgical intervention, anticoagulation needs to be more cautious. Low molecular weight heparin is more recommended than heparin for anticoagulation therapy in such patients.

5. Patients with epidural analgesia

Recommendation: In trauma patients, after placing an epidural catheter, enoxaparin should be continued for anticoagulation treatment 12 hours later. Avoid delaying the use of anticoagulant drugs for more than 24 hours.

6. VTE imaging monitoring strategy for trauma patients

Recommendation: Most trauma patients do not recommend daily VTE imaging screening. It is recommended to perform weekly imaging screening in high-risk VTE trauma patients who cannot be used for anticoagulation.

Discussion: Most trauma patients do not recommend daily VTE imaging screening, which does not reduce the incidence of VTE and fatal PE. And some false-positive imaging results have led to unnecessary therapeutic anticoagulation regimens. Some trauma centers routinely perform imaging evaluations in low-risk VTE trauma patients to identify acute or chronic DVT, which may be used to identify, treat, and prevent patients with venous insufficiency, venous stasis, ulcers, or walking pain. What needs to be vigilant is that increasing the frequency of imaging evaluation can increase the incidence of VTE in patients (increased false positives), but it is not conducive to determining which is a typical clinical VTE or chronic VTE (past medical history, concealed VTE). At present, it is recommended that in high-risk trauma patients who cannot be anticoagulated with drugs, VTE imaging evaluation of both lower limbs can be performed daily, which can reduce the occurrence of PE.

7. VTE anticoagulation strategies for patients with VV-ECMO

Recommendation: Although VV-ECMO uses systemic anticoagulation, evaluation and intervention are still needed for patients with high-risk VTE. We need to use CT to evaluate the veins of the lower extremities and IVC.

Discussion: In VV-ECMO patients, thrombotic events often occur in the pipeline and the patient’s blood vessel. We use system anti-coagulation and anti-coagulation-coated tubing to reduce the risk of embolism. Studies have reported that the incidence of VTE in VV-ECMO patients may be as high as 18%. Intra-cervical dual-line catheterization has a higher risk of VTE than intra-cervical-femoral venous catheterization. Thrombosis often occurs in the internal jugular vein and the inferior vena cava. After ECMO weaning, the incidence of DVT is as high as 60%. Due to the low efficiency of ultrasound examination of the iliac vein and vena cava, CT venography is recommended for this type of patients. Imaging screening of the lower limbs and puncture site is recommended. Studies have reported that the rate of thrombosis at the puncture site (71%) is higher than that of independent vena cava thrombosis (47%), and the diagnostic accuracy of ultrasound will decrease. Among patients with DVT, 16% of patients have PE, and it is recommended that adequate preventive anticoagulation is required after ECMO weaning.

8. Timing of preventive inferior vena cava filter implantation

Recommendation: At present, it is controversial to implant the preventive inferior vena cava filter (IVCF) for trauma patients, but for trauma patients with high risk of VTE, and because of bleeding and other conditions, the inferior vena cava filter can be considered.

Discussion: IVCF is indicated for patients with a clear proximal (popliteal fossa, femur or iliac) DVT or PE, and absolute contraindications for therapeutic anticoagulation; VTE recurrence with anticoagulation complications or adequate anticoagulation . Although early studies have confirmed that the incidence of PE in trauma patients is lower after IVCF, recent studies have confirmed that IVCF does not reduce the mortality rate of patients, and will increase the incidence of DVT. We only recommend the placement of an inferior vena cava filter for trauma patients with high risk of VTE, and if anticoagulation is not possible due to active bleeding and other conditions. High risks include: severe head injury combined with long bone fractures, head injury combined with spinal trauma, multiple long bone fractures, and severe pelvic fracture combined with long bone fractures.

9. the placement time of the inferior vena cava filter

Recommendation: The filter should be removed as soon as possible after the patient’s condition is stable and drug anticoagulation can be performed; if the patient’s filter is placed for a long time, it can also be considered that the filter is placed and the drug is anticoagulated.

Discussion: Prolonged IVCF placement time is related to DVT, chronic pain, inferior vena cava thrombosis, inferior vena cava perforation, filter displacement, etc. As the storage time increases, the difficulty of taking it out also increases. After the PE risk is lifted, the IVCF should be removed 1-2 months after placement. The American Thoracic Association recommends that IVCF be removed six months after the occurrence of PE regardless of whether the patient can be anticoagulated. The US FDA recommends that the filter be removed as soon as possible after the patient can be anticoagulated with the drug. It is recommended to make an individual plan for the removal of the patient after the filter is inserted to avoid related complications.

10. Anti-Xa factor monitoring and anticoagulant dose adjustment

Recommendation: The use of low molecular weight heparin for anticoagulation requires the use of anti-Xa factor monitoring, and timely adjustment of the anticoagulant dose to reduce the incidence of bleeding.

Discussion: Anti-Xa factor is a test to evaluate the degree of inhibition of heparin or low molecular weight heparin on factor Xa. It is recommended to perform an anti-Xa test 4 hours after the third enoxaparin. The factor Xa level of preventive anticoagulation therapy is maintained at 0.2-0.4 IU/mL, and the therapeutic anticoagulation is >0.5 IU/mL. If the level of anticoagulant factor Xa is too low, the anti-Xa test should be performed again 4 hours after increasing the dose of enoxaparin 10mg. It is recommended that the dose of enoxaparin is not greater than 60 mg bid; if the level of anticoagulation factor Xa is still too low after increasing the dose of low molecular weight heparin, heparin resistance or antithrombin-III deficiency needs to be considered; occult venous thromboembolism with hypercoagulability Block load or other possible factors should be further evaluated. A study confirmed that VTE anticoagulant therapy under anti-Xa factor monitoring can reduce the incidence of VTE, and 50% of patients did not achieve the expected anticoagulant effect. Drug anticoagulation under monitoring can also reduce the risk of bleeding; in addition, since low molecular weight heparin is metabolized by the kidney, we should also pay attention to renal function (creatinine clearance).

11. Anticoagulant dose adjustment under TEG monitoring

Recommendation: There is currently no evidence to recommend the use of TEG to monitor the adjustment of preventive anticoagulant doses in trauma patients.

Discussion: Many trauma patients show hypercoagulable state under TEG monitoring, and there is a high-risk state of VTE. At present, the adjustment of anticoagulant dose in trauma patients is still based on anti-Xa factor monitoring, but TEG can more comprehensively reflect the patient’s coagulation function. In a study of 61 patients after trauma and surgery, patients had a 31% incidence of DVT. TEG has clinical significance in judging whether there is DVT, but there is no statistical significance in anti-Xa factor monitoring. The R time for TEG measurement in patients with DVT is shorter. 87 patients were divided into TEG monitoring group (R adjusted to 1-2min) and conventional anticoagulation group. There was no significant difference in R value between the two groups. The anti-Xa factor did not increase significantly in the TEG monitoring group.

TEG monitoring cannot predict the level of anti-Xa factor. At present, no clinical studies have confirmed that TEG monitoring has a guiding role in the dose adjustment strategy of drug anticoagulation in trauma patients.

12. The plan for adjusting the anticoagulant dose of obese patients according to body weight

Recommendation: For patients whose BMI exceeds 30 kg/m2, the anticoagulant dosage regimen can be adjusted accordingly: according to the level of anti-Xa factor and the incidence of VTE in ICU trauma patients.

Discussion: Obese trauma patients (BMI greater than 30 kg/m2) are considered to be more likely to have a hypercoagulable state and develop VTE. Weight-adjusted enoxaparin initial prevention program (0.5 mg/kg, 0.6 mg/kg or 30 mg for 50-60 kg patients, 40 mg for 61-99 kg patients, and 50 mg for >100 kg) combined with anti-Xa factor Monitor to maintain the level at 0.2-0.4 IU/mL. In a study on anticoagulation therapy for obese and non-obese trauma patients, the weight-based anticoagulant dose adjustment and the simultaneous detection of anti-Xa factor levels did not increase the incidence of bleeding complications in patients. In another large-scale study, the use of high-dose anticoagulants in patients with overweight (BMI>40 kg/m2) did not increase the risk of bleeding. For trauma patients with a high risk of bleeding, the anticoagulant dose should be adjusted more carefully according to body weight.

13. Other high-risk situations and the timing of suspension of preventive drugs for anticoagulation

Recommendation: In patients with active bleeding or coagulopathy, preventive anticoagulation should be suspended or delayed, and mechanical prevention should be performed.

Discussion: Traumatic coagulopathy caused by early severe trauma will quickly change to a hypercoagulable state after correction, and we should evaluate to start preventive anticoagulation therapy as soon as possible. In patients with traumatic coagulopathy, it is recommended to start low-molecular heparin anticoagulation after initial resuscitation and correction of coagulation dysfunction, although the coagulation function has not fully recovered. Suspending or delaying preventive anticoagulation will undoubtedly increase the incidence of VTE, so anticoagulation should be done as soon as possible after the bleeding is controlled. In patients with medium to high risk of VTE and contraindications to drug anticoagulation, mechanical prophylaxis is required.

14. Does the anticoagulant dose of pregnant trauma patients need to be adjusted?

Recommendation: The dose of preventive anticoagulation for pregnant trauma patients needs to be adjusted.

Discussion: Adjust the dose according to the patient’s weight and creatinine clearance. The initial dose is enoxaparin 30 mg, bid; weight>90 kg is adjusted to 40 mg, bid; adjusted according to the level of anti-Xa factor: the target is 0.2–0.4 IU/mL .

15. When to suspend or terminate preventive drug anticoagulation

Recommendation: Only in the event of fatal active bleeding or heparin resistance, it is necessary to suspend or terminate preventive anticoagulation.

Discussion:

Once patients start preventive drug anticoagulation, do not easily pause. Stopping anticoagulation for more than 24 hours or interrupting anticoagulation will cause the incidence of VTE to increase significantly. However, clinical interruption of anticoagulation is still very common. It is reported that 40% of trauma patients have anticoagulation interruption due to various reasons.

There is still controversy as to which invasive procedures should be suspended after anticoagulation. Absolute anticoagulation contraindications include active bleeding, craniotomy and spinal surgery in the near future. Whether these patients restart anticoagulation after surgery or 24-72 hours after bleeding has stopped is still controversial.

For trauma patients with very high-risk VTE, the anticoagulation time still needs repeated evaluation and dynamic observation. Once the drug anticoagulation is suspended, physical prevention should be taken immediately.

(source:internet, reference only)

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