IC92

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IC91 | IC93 | MCQ-Intensive Care & resuscitation | Finals Black Bank

Question

[Apr08]

When considering the problem of cardiac tamponade due to CVC insertion all are true EXCEPT?
A. positioning the CVC just above the junction of the right atrium and SVC will avoid  the problem 
B. visceral chest pain with drug infusion is an early sign
C. symptoms develop within 1 week
D. L sided CVL positioned at midpoint of brachiocephalic vein will not cause tamponade
E. more common in catheters with more lumens

ANZCA Version [Apr08]

Each of the following statements regarding cardiac tamponade as a complication of central venous
lines is true, EXCEPT:
A. catheters with multiple lumens carry greater risk
B. for a left sided catheter, placement of the tip at the mid-point of the brachiocephalic vein is
safe
C. it usually occurs within the first week following insertion
D. placement of the catheter tip above the junction of the right atrium and superior vena cava
will avoid this complication
E. visceral chest pain with drug infusion is an early symptom

Comments

ANZCA Version

Some of the options for this question seem to come straight out of the BJA Editorial referenced below, and my worked answer below is based on that article alone.--Getafix 02:05, 18 Mar 2011 (EDT)

A: TRUE..."Stiffer catheters are more likely to perforate. Stiffness is a function of the composition of the catheter (Silastic probably being safest) and the number of the lumen (a function of the greater diameter and presence of ‘septa’ within the catheter)."

B: TRUE..."Zone C (mid‐point, left innominate vein). This is a suitable site for the tip when the catheter is introduced from the left internal jugular or subclavian vein, and reduces the risk of SVC perforation." (In reference to a diagram of the heart and great vessels showing various "zones" for the CVC tip)

C: TRUE..."Most cases occur in the first week after insertion"

D: FALSE (and answer to choose)..."the pericardium may ascend alongside the medial wall of the SVC by up to 5 cm (mean 3 cm). Thus, placement just proximal to the atrium does not obviate the risk of tamponade".

E: TRUE..."This results in two warning signs: visceral‐type chest pain on infusion of drugs or parenteral nutrition solutions and a curved appearance of the distal catheter seen on chest x‐ray"



Black Bank Version

A - TRUE

  • Recommended position for appropriate for all access points

B - TRUE

  • Dyspnoea, chest pain, tachycardia, hypotension and, specifically, pulsus paradoxus. However, their non-specific nature makes the diagnosis difficult and accounts for the high mortality associated with the condition.

C - TRUE

  • Symptoms can develop over a few minutes to a few days.

D - TRUE

  • Acceptable position for left-sided catheters

E - FALSE

  • Catheter material (polyurethane more than silastic)
  • The risk of infection may also be increased by increasing the number of lumens

Further comments

My answer is E.

Risk factors for causing this complication are: tip position (just above the atrial/SVC junction is recommended location), catheter material (polyurethane more than silastic), hyperosmolar fluids (increased risk of erosion). Other possible factors - high pressure/infusion volumes, tips with excessive movement (PICCs > CVCs).

A - TRUE - recommended position for appropriate for all access points
B - TRUE - chest pain is one of the symptoms
C - TRUE - symptoms can develop over a few minutes to a few days. I suppose it depends on type and volume of stuff you would put down the catheter.
D - TRUE - acceptable position for left-sided catheters
E - FALSE - not a recognised risk factor. If it was, we would all be prob only using single lumen catheters!

Try looking at these 2 references:

  • BJA 2000, 85(2): 188 - An editorial that is more than 8 years old now, but still made interesting reading
  • BJA 2007, 99(3): Pg 384 - A case report of Cardiac tamponade from PICC line, but discusses central lines in general. Probably the article that our dear examiners read and thought was a good idea to include on the exam!

Adrenaline - 15/2/2009

Or is it? Back to the old examiner word games - if the actual answer was "WILL PREVENT" then it has to be incorrect, as the old adage in medicine says never say never and never say always. As for evidence that increasing lumens increases complications, I give you this... "It seems likely that the risk of perforation with a CVC increases with its diameter and stiffness (and other factors being equal, increasing the number of lumens in a CVC does increase its diameter and stiffness)19. The risk of infection may also be increased by increasing the number of lumens, although this finding seems less secure32,33. Unquestionably, however, increasing the number of lumens in a CVC increases its cost (Table 2)." [A prospective clinical audit of central venous catheter use and complications in 1000 consecutive patients http://www.aaic.net.au/default.asp?D=2002250]. Therefore, if you had catheters indentical in stiffness and diameter, and the only difference was in the number of lumens then perhaps it wouldn't be a problem. But given that more lumens generally means a larger and stiffer catheter A might well be the "incorrect" answer (thus the answer for this MCQ). --Dr_Al 22:57, 26 Dec 2009 (EST)

References

  • BJA 2007, 99(3): Pg 384 - A case report of Cardiac tamponade from PICC line, but discusses central lines in general. Probably the article that our dear examiners read and thought was a good idea to include on the exam. - minkel777
  • BJA 2000, 85(2): 188 - An editorial that is more than 8 years old now, but still made interesting reading - - minkel777 (options seem to come word for word from this editorial)
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