Neonatal MCQ Board Review

[drnono]

Many thanks Dr. Rehman and of course Dr Manzar.. it is really a great TRAINING sourcs as Dr Stefan said..

 I have  understood from the PALS  algorithm  that they start with Adenosine in wide complex regular tachycardia only to differentiate between SVT and VT ( SOMETIMES DIFFICULT ). "Adenosine also has a differential diagnostic ability with both narrow- and wide-complex regular tachycardia because of the absence of adverse hemodynamic effects. Adenosine  transiently blocks the AV conduction and sinus node pacemaking activity . It terminates SVT but is not effective for nonreciprocating atrial tachycardia, atrial flutter or fibrillation, and ventricular tachycardia. OF COURSE it is not recommended in irregular (polymorphic) tachycardia" (PARK CARDIOLOGY 5ed ).  

As mentioned in neonatal cardiology 2nd ed :A wide QRS tachycardia should always be treated as ventricular tachycardia until a definite diagnosis is made.The authers prefer to start with Amiodarone which is efficacious for both SVT and ventricular tachycardia making it a reasonable choice if the diagnosis is uncertain. Lidocaine blocks fast sodium channels thereby shortening action potential duration and the refractory period primarily in Purkinje fibers and in ventricular myocytes. Giving the clearence of the strip as wide regular (monomorphic) tachycardia, the 1st possible diagnosis still ventriculat tachycardia so I beleive that LIDOCAINE is still the best choice for Q2..

 

 

[rehman_naveed]

29 minutes ago, drnono said:

Many thanks Dr. Rehman and of course Dr Manzar.. it is really a great TRAINING sourcs as Dr Stefan said..

 I have  understood from the PALS  algorithm  that they start with Adenosine in wide complex regular tachycardia only to differentiate between SVT and VT ( SOMETIMES DIFFICULT ). "Adenosine also has a differential diagnostic ability with both narrow- and wide-complex regular tachycardia because of the absence of adverse hemodynamic effects. Adenosine  transiently blocks the AV conduction and sinus node pacemaking activity . It terminates SVT but is not effective for nonreciprocating atrial tachycardia, atrial flutter or fibrillation, and ventricular tachycardia. OF COURSE it is not recommended in irregular (polymorphic) tachycardia" (PARK CARDIOLOGY 5ed ).  

As mentioned in neonatal cardiology 2nd ed :A wide QRS tachycardia should always be treated as ventricular tachycardia until a definite diagnosis is made.The authers prefer to start with Amiodarone which is efficacious for both SVT and ventricular tachycardia making it a reasonable choice if the diagnosis is uncertain. Lidocaine blocks fast sodium channels thereby shortening action potential duration and the refractory period primarily in Purkinje fibers and in ventricular myocytes. Giving the clearence of the strip as wide regular (monomorphic) tachycardia, the 1st possible diagnosis still ventriculat tachycardia so I beleive that LIDOCAINE is still the best choice for Q2..

 

 

Thanks @drnono for such a nice detailed answer, if u see the ECG in the question it is wide complex tachycardia, HR around 175, so not at all SVT by any means or even by definition. We can debate about lidocaine vs adenosine but I think from exam perspective I still stand that lidocaine is the answer and correct in book but @tarekhas a point and reference we can't ignore especially when there is VT and SVT aberency.

 Thanks for your comments. Don't know is there any pediatric cardiologist in this group who can comment to guide all folks.

[Dr Vira]

Dear Naveed

I thoroughly enjoyed solving the MCQs. I am yet to finish it though. I have a query. Q31 . It is mentioned the right answer is increasing the frequency. But as a rule , in HFOV frequency is disease specific & not altered. In the book Goldsmith, it is written that for severe hypocarbia, amp should by decreased by 5-10 & in not so severe hypocarbia by 2-5 cm . So  the most apt answer to this question might be decreasing the amp by 6? 

Regards

Viraraghavan V Ramaswamy

MD, DM (Neonatology), DNB (Neonatology), Intern Neonatology (OUH, Oslo)

[rehman_naveed]

Hi Dr. Vira

Thanks for the comments and I am glad that you like our book useful. The Frequency is not appropriate for this 630gm baby, change in frequency affect your tidal volume and hence CO2. Hz of 10 is too low for this baby and hence the first thing to change since PCo2 is too low, we need to act aggressively on it since the change in frequency affect PCO2 more than amplitude. Also as mentioned in the text, amplitude should never be changed by this number i.e by 6 but slowly in increments of 2.

Regards

Naveed

[Dr Vira]

Thanks for your reply Dr Naveed. Just one thing. In HFOV, CO2 elimination is directly proportional to Vt square X hz. So change in amplitude (vt) will affect the CO2 more than the change in frequency ( Ref - Goldsmith). Also, if we strictly go by books which I do, for RDS, the usual frequency suggested is 8-10 Hz and for obstructive physiology like BPD & MAS, it is 6-8 ( Ref - Goldsmith). I did hear one speaker in a recent forum like you, suggesting that this frequency is too low. Thanks again for the wonderful book.

Regards

[yangw126]

Thanks！It is  a great training book ！