POTD: Sterility of US Guided PIVs

How sterile does an ultrasound guided peripheral IV need to be?

Are there guidelines?

• The European Society of Radiology Ultrasound Working Group recommends probe covers for all procedures including US guided PIVs.

• ACEP and AIUM policy statements recommend single use gel packetwith probe cover to match level of procedural sterility, so US guided PIVs can be done with a non sterile probe cover.

  • Why sterile gel? Most infections in US guided PIVs stemmed from contaminated gel.

• In reality, practices vary widely among institutions and practitioners within those institutions.

What are the infection concerns?

• Contamination with blood. So we worry about spreading infection to the next patient. Otherwise, the procedure itself does not need full sterile technique.

• Hep C is ~30nm. Hep B is ~50nm. HIV is ~110nm.

• So, our probe cover should have a pore size of < 30nm to prevent spread of infection onto probe and then the next patient.

• If the probe is contaminated with blood, current guidelines say we can use "low level disinfection," which is soap and water or ammonia wipes.

The probe cover options:

• Tegaderm: It's cheap, easy. the 3M Tegaderm claims to have a pore size of 27nm. BUT, the manufacturers recommend against the tegaderm because of concern for damaging the probe lens and it may affect the warrantee. Anecdotally, people have been doing this for a decade+ without any lens damage. Some people suggest adding a thin layer of gel between the transducer lens and tegaderm to prevent damage.

  • It should be noted that some IV dressings are designed to be breathable and have a much larger pore size.

• Condoms: Also cheap, easy. Pore size 110nm, so it'll block HIV but not HCV.

• Sterile gloves: Can stick the probe into the prefolded cuff. Varies in pore size but should hinder viral transmission.

• Sterile probe cover: Should hinder viral transmission, but not necessary for US guided PIV.

The bottom line

• Wear non sterile gloves during the procedure.

• Use a single use gel packet.

• Use some kind of probe cover. Tegaderm or a sterile glove seem to be a good options.

• Wipe down the probe after use.
  

References

• EM:RAP LIN sessions, Jan 2019

• ALIEM: https://www.aliem.com/2018/09/ultrasound-guided-periphal-iv-time-to-clean-up-our-act/

POTD: COAGs and NOACs

What is the role of testing the COAGs of a patient on NOACs?

Review: the coagulation cascade and PT/PTT

*Thrombin converts fibrinogen to fibrin and the time it takes is the TT (normal is < 20 seconds).

NOAC = Novel oral anticoagulants

• Thrombin inhibitor 

  • Dabigatran (Pradaxa)

•  Factor Xa inhibitors

  • Rivaroxaban (Xarelto)

  • Apixaban (Eliquis)

  • Edoxaban (Savaysa)

*Warfarin is a vitamin K antagonist affecting factors II (prothrombin), VII, IX, X and proteins C, S, and Z

Where NOACs affect the coagulation cascade

https://doi.org/10.2215/CJN.02170218

Coags and NOACs

The takeaway…

• NOAC levels are difficult to monitor.

• With dabigatran, a normal PTT can reassure you the patient is not supratherapeutic.

• With rivaroxaban, a normal PT/INR can reassure you the patient is not supratherapeutic.

• Otherwise coags may be elevated, but the values will not be of clinical utility.

Sources

• Blann AD, Lip GYH. Laboratory Monitoring of the Non–Vitamin K Oral Anticoagulants. J Am Coll Cardiol. 2014;64(11):1140–1142. https://doi.org/10.1016/j.jacc.2014.07.010

• Cuker A, Siegal DM, Crowther MA, Garcia DA. Laboratory measurement of the anticoagulant activity of the non-vitamin K oral anticoagulants. J Am Coll Cardiol. 2014;64(11):1128–1139. https://doi.org/10.1016/j.jacc.2014.05.065

• Noll, Andrew. Coagulation Assays and the New Oral Anticoagulants. American College of Cardiology June 22, 2015: https://www.acc.org/latest-in-cardiology/articles/2015/06/22/12/06/coagulation-assays-and-the-new-oral-anticoagulants

• Thrombosis Canada. Use And Interpretation Of Laboratory Coagulation Tests In Patients Who Are Receiving A New Oral Anticoagulant (Dabigatran, Rivaroxaban, Apixaban). 2013: http://thrombosiscanada.ca/guides/pdfs/NOAC_Monitoring.pd

POTD: Lyme Carditis

Lyme Carditis 

Lyme disease is caused by the spirochete Borrelia burgdorferi, transmitted by the Ixodes tick. Mostly in 2 regions:

1. Northeast (Mid-Atlantic and New England states), and

2. North Central (Wisconsin and Minnesota)
   
   

This pearl will focus specifically on lyme carditis and not other clinical manifestations of lyme. 

3 phases of the disease:

1) early localized 

2) early disseminated

3) late 

Lyme carditis occurs in 1% of patients with lyme and during the early disseminated phase. This is typically 1-2 months after infection. 

Symptoms

• lightheadedness

• syncope

• shortness of breath

• palpitations

• chest pain

What's going on?

• Causes AV conduction abnormalities that can vary rapidly; so a person can go from a first degree block to complete AV nodal block within minutes! They can also revert back within minutes.

• Highest risk for progression to complete block is PR > 300

• Can cause a myopericarditis that is self-limited

• Sudden cardiac death has been reported

Diagnosis

• Need positive lyme serologies -- ELISA and confirmatory Western blot

• These tests can test for IgM, but this gives higher false positives. Since lyme carditis occurs during the early disseminated phase, it is better to screen for lyme IgG

Management

• Patients with PR > 300 should be hospitalized, given IV antibiotics and monitored with tele

• Ceftriaxone 2g/day IV in adults (50-75mg/kg/day IV in children)

• When PR becomes < 300, can switch to oral antibiotics (doxycycline 100mg BID, amoxicillin 500mg TID, or cerfuroxime 500mg BID)

• Need a total of 21-28 days of antibiotic therapy

*It should be noted that chronic lyme disease has come to refer to an entirely different entity: https://www.nybooks.com/daily/2018/07/25/the-challenge-of-chronic-lyme/ 

Happy hiking!