5/28/2012

Pacemaker - Non-capture

Attempt to detect the underlying rhythm. (Postop. patient)
Click on the image to enlarge.

Differential Cyanosis (& Clubbing)

21 yr old man with Unrepaired PDA and Severe Pulmonary hypertension.
Cyanosis and Clubbing are present in the feet.
No cyanosis or clubbing in the hands.
(Both feet were affected by post-polio paralysis as a young child and now, wheel chair bound)

5/23/2012

Retroaortic Innominate Vein

Panel A: (6th week of gestation). 1 & 2 - Right and Left anterior cardinal veins, 3 - Primitive aorta, 4 & 5 - Superior and Inferior transverse venous plexus, 6 - Right & Left common cardinal veins, 7 & 8 - Right and left posterior cardinal veins, 9 - Sinus venosus, 10 - Vitelline vein, 11 - Umbilical vein, 12 - Developing IVC

Konstantinov I. E. et al.; Ann Thorac Surg 2003;75:1014-1016

5/19/2012

Pulsus Paradoxus

How to meaure it?
(Click on image to enlarge)
You need a manual sphygmomanometer.
We are looking for decrease in systolic BP between inspiration and expiration.
First, determine the BP of the patient. Then, raise the pressure in the cuff above the measured systolic pressure and bring it down slowly (2-5 mmHg steps) - holding the cuff pressure at each level for at least 2 breaths. When Koratkow sounds are first heard (take this as expiratory systolic BP), these will be intermittent because these sounds are heard only in expiration and not heard during inspiration. Thus, in the initial part of the descent, you only hear Koratkow sounds intermittently. (First arrow in the figure above)

Continue to decrease the cuff BP (slowly) - holding at each step for at least 2 breaths. There will be point when Koratkow sounds are heard continuously. In other words, you would suddenly hear more Koratkow sounds than before. This is the inspiratory - systolic BP (Second, lower arrow in the figure above).

Difference between expiratory systolic BP and inspiratory systolic BP should be < 10 mmHg. If higher (20 or above), pulsus paradoxus is supposed to be present. Pulsus paradoxus is the exaggeration of a normal phenomenon.

Pulse ox trace and Arterial line trace - if available, are also useful to recognize pulsus paradoxus.

Other signs of pericardial tamponade (or restriction) is Kussmaul sign. This is inspiratory increase in JVP.  This is what is opposite of normal. Apparently, some how, the term paradoxus has transferred to pulsus paradoxus?!
(Figure from Cardiovascular Dynamics by Robert F. Rushmer, 3rd ed. 1970 W.B.Saunders Company, Philadelphia.)

5/13/2012

ICU: Fenaldopam

DA1 receptor agonist.
Not approved for children.

Pediatr Crit Care Med 2008;9:403-6.
n=13, in PCICU
Dose for renal effect: 0.01 - 0.2 mcg/kg/min was used
Mean infusion rate of 0.07 +/- 0.08 mcg/kg/min
Urine output increased in the first 24 hrs. (1.8 to 2.7 ml/kg/hr)
Mean BUN increased from 41 to 47.
No change in creatinine.

BMC Anesthesiology 2008
Pharmacokinetics in Children was studied.
n=77, in operating room,
To produce controlled hypotension (as a strategy to control surgical bleeding).
In the blinded stage of the study, 4 doses were given 0.05, 0.2, 0.8 & 3.2 mcg/kg/min. 0.8 & 3.2 mcg/kg/min produced hypotension.
In the open label, titration part of the study, dose range of 1.0 - 1.2 mcg/kg/min produced continued blood pressure reduction.
Doses above 1.2 mcg/kg/min did not produce additional reduction in BP, but increased HR.

Statistics - Normal Distribution Curve

(Corresponding centiles were added. Of course, there won't be any decimal points to any centile. Example: Centiles will be 84th or 85th, not 84.1. 84.1 will belong to 85th centile.) Click on the image to enlarge.

5/11/2012

DC Cardioversion: Apparent VT. But,...

Click on the image to enlarge
Apparent wide-complex tachycardia. Generally, it is safe (and recommended) to provide treatment as "wide-complex tachycardia". However, in this patient, his baseline EKG was well known and has wide-complex QRS from acute myocarditis. And, based on 12-lead EKG it was decided that this is SVT with wide-complex QRS. Therefore, synchronized cardioversion was attempted and delivered (1 J/kg dose was used for this patient).


Probably due to wide QRS complexes, the defibrillator had hard time to "sync" the shock and automatically, switched off the sync and delivered the shock. Note: the QRS complexes after the DC cardioversion are paced beats (Epicardial, temporary pacing wire at VVI 100 bpm).

5/01/2012

Newborn with Congenital Heart Disease - Clinical Approach

Algorithm for diagnosis of congenital heart disease in newborn
Click on the image to enlarge
Sorry, can't remember the source of this flow chart.