Catheter-related upper extremity DVT

26 Mar

QUICK PEARLS:

The majority (70-80%) of thrombotic events in the upper extremity deep veins (subclavian, axillary, brachial) occur in the presence of IV catheters.

 

Any catheter has the potential to cause thrombosis. Think about PIV, PICC, tunneled and non-tunneled central catheters, ports and pacemakers.

 

In addition to the classic risk factors that you commonly consider for DVT (prior surgery, malignancy, h/o DVT, etc.), specifically catheter-associated thrombosis is more likely with:

-large-diameter catheters (more likely to have stagnate blood v. free flowing)

-PICC as compared to centrally placed catheters

-catheter malposition (In one study, DVT developed in 46% of patients whose catheter tip was in the innominate vein or junction of the immoninate vein with the SVC, compared with 6% of patients with a properly positioned catheter)

-chemical irritation (potassium chloride, antibiotics such as vancomycin, diazepam, hypotonic and hypertonic electrolyte solutions)

 

Clinical presentation: inability to withdraw blood, phlebitis, extremity edema

 

Diagnosis is made with Doppler ultrasound.

 

Treatment involves observation, anticoagulation to prevent embolization, and removal of the catheter. Prophylactic systemic anticoagulation is not routinely recommended in this population.

 

Submitted by K Estes.

 

References:  Luciani, et. Al. Catheter-related upper extremity deep venous thrombosis in cancer patients: a prospective study based on Doppler US. Radiology. 2001;220(3):655. PMID 11526263

Uptodate.com; picture

Penetrating Neck Injuries (PNI) – a few important reminders

23 Mar

REMEMBER THIS:NeckInjuryZones1

 

  • Penetrating neck injuries (PNI) are defined by injuries that violate the platysma
  • Zones of injury (see picture) have been defined to help the clinician describe the injury and attempt to predict degree of morbidity
  • PEARL: If clinical signs of vascular or aerodigestive injury or if hemodynamically unstable, then the treatment is operating room exploration
  • Otherwise, obtain CT angiogram and the following management depending on the corresponding zone:
    • Zone 1 -> esophageal imaging, bronchoscopy, angiography
    • Zone 2 -> angiography, esophageal imaging, bronchoscopy, operating room for mandatory exploration
    • Zone 3 -> angiography
  • PEARL: there are conflicting studies, but it is usually safe to clear the cervical spine in a patient with PNI and no focal neurologic deficits

 

  • Pitfalls:
    • Never remove objects impaled in the neck
    • Avoid probing neck wounds and clamping vessels in the neck
    • Never discharge a patient with PNI and no injuries identified on CTA; always admit these patients for observation
    • To avoid morbidity (mediastinitis, abscess, empyema), never delay esophageal imaging in patients with potential esophageal injury

 

 

Submitted by K Estes

 

References: Critical decisions in emergency medicine. October 2011, vol 26, number 2.

Propofol Infusion Syndrome

19 Mar

A rare complication of propofol infusion (estimated <1%) with high mortality (upwards of 33%)

 

Risk factors include

  • High doses (>4 mg/kg/hr or >67 mcg/kg/min)
  • Prolonged use (>48 hours)
  • Young age
  • High fat and low carbohydrate intake
  • Inborn errors of mitochondrial fatty acid oxidation
  • Concomitant catecholamine infusion

 

Presentation

  • Bradycardia
  • Severe metabolic acidosis
  • Cardiovascular collapse (EKG appears “brugada-like” with convex-curved ST elevation in V1-V3, also RBBB, arrhythmia, heart block)
  • Rhabdomyolysis
  • Hyperlipidemia
  • Renal failure
  • Hepatomegaly
  • Lipaemic serum (say what??? -> milky white serum due to high fat content- see picture)

lipaemic serum

Treatment

  • Discontinuation of propofol
  • Consider pacing
  • Carnitine supplementation (theoretical benefit)
  • Hemodialysis and ECMO (benefit in a few case reports)
  • Good ol’ fashioned supportive care

 

Submitted by K Estes

 

References:  uptodate.com; lifeinthefastlane.com

do the clothes make the doctor?

17 Mar

DO PATIENTS CARE HOW YOU’RE DRESSED?

Interesting brief article about a study from the BMJ

 

QUICK HIGHLIGHTS:

Physician attire was defined as:

  • personal or hospital-issued clothing (e.g. scrubs), +/- white coat
  • formal attire = collared shirt, tie and slacks for male physicians and blouse (with or without a blazer), skirt or suit pants for female physicians.
  • casual attire: e.g. polo shirts and blue jeans; or not the formal attire listed above

 

70% of studies analyzed found that patients prefer professional attire with or without white coats

4/7 studies focusing on surgeons, gynecologists, and emergency medicine, found that their attire was less important than that of a family or general physician.

only 4 of the 10 US-based studies reported that attire influenced patient perceptions regarding their physician   (other countries seemed to care more, from UK/Europe, Asia, Austrailia, etc).

acute care settings (e.g. the ED) : attire seemed to matter less.

 

Interesting, though as EM docs, we seem to get a pass.

 

References: article; BMJ article; picture

Kanavel signs for flexor tenosynovitis

12 Mar

(some via an old post, but came up recently, and was the most basic evidence found on a pubmed biopsy.  if anyone knows of any larger data/studies, please share in the comments section)

CLASSIC TEACHING:
Kanavel signs for flexor tenosynovitis

  • pain on passive extension (early finding)
  • finger held in flexion
  • uniform swelling of finger
  • tenderness to percussion along flexor tendon sheath (late finding)



HOW GOOD IS OUR H&P?
incidence of H&P findings in 75 patients with flexor tenosynovitis

  • fusiform swelling (97%)
  • pain on passive extension (72%)
  • semiflexed posture (69%)
  • subcutaneous purulence (68%)
  • tenderness along flexor sheath (64%)
  • elevated WBC (59%)
  • diabetes mellitus (35%)
  • skin necrosis (23%)
  • fever (17%)

 

overall, the 4 signs aren’t perfect, but are there individually in at least 2/3rds of patients

one study of 41 patients with flexor tenosynovitis:

  • all patients had tenderness along the flexor tendon sheath and pain with passive extension.
  • only 22/41 patients (54%) had all four Kanavel signs

TREATMENT TOOLBOX:

IV antibiotics: staph and strep coverage, think pasturella for bite-associated infections

–surgery: consult your hand surgeon ASAP

Kanavel signs for flexor tenosynovitis (REVISITED)

  • pain on passive extension (early finding)
  • finger held in flexion
  • uniform swelling of finger
  • tenderness to percussion along flexor tendon sheath (late finding)
 

Reference(s): uptodate.com: infectious tenosynovitis; study; picture.; article

outpatient treatment failture in cellulitis

10 Mar

via an old NEJM Journal Watch recap:

QUICK HITS:

2 Canadian EDs

102/499 patients (21%) failed outpatient antibiotic therapy (needed different abx or admission)

predictors of treatment failure:

  • temp > 38°C at triage (OR = 4.3, 95% CI = 1.6 to 11.7)
  • chronic leg ulcers (OR = 2.5, 95% CI = 1.1 to 5.2)
  • chronic edema or lymphedema (OR = 2.5, 95% CI = 1.5 to 4.2)
  • prior cellulitis in the same area (OR = 2.1, 95% CI = 1.3 to 3.5)
  • cellulitis at a wound site (OR = 1.9, 95% CI = 1.2 to 3.0)

 

Makes sense.  Worth considering.  Good follow-up is key, also.

 

References: journal watch, original article; picture

visual aid: dense MCA sign

6 Mar

was reminded of the useful dense MCA sign by this article in December’s JEM (good pictures, though the article was written by radiologists with variably subtle CT findings):

denseMCA

QUICK HITS:

increased attenuation of [a segment of] the middle cerebral artery 

can give an MCA dot sign when the vessel is seen end-on.

usually seen in 90 min of the event

for more visual aids, check out radiopaedia.org, which has a video link + several cases you can scroll through like a real CT scan.

quick imaging overview with pictures over here as well.

 

References: JEM article; radiopaedia.org + picture; radiology assistant + picture

 

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