ICU: Venous Blood Gas (What is it good for?)

VBG compared to ABG

pH .03 lower

PvCO2 5.8 higher

PvCO2 less than 45 on room air rules out hypercarbia (Journal of Emergency Medicine
Volume 28, Issue 4 , May 2005, Pages 377-379)

Venous is as good as arterial blood gases in DKA (Emerg Med Austr 2006;18:64)

pH was almost identical, bicarb was close enough

Central (SVC) pH, bicarb, BE, and lactate agrees with arterial (Emerg Med J 2006;23:622)

New method can calculate an ABG from a VBG (Emerg Med J 2009;26:268)

VBG is just fine for COPDers for pH, HCO3 and CO2 (Eur J Emerg Med 2010 Oct;7(5):246-8)

Source: http://text.emcrit.org/1-resus/abgs.htm

History: Werner Forssmann

The Miscellaneous Blog: History: Werner Forssmann


EKG: Pacing, Interpret this.

What type of pacing is used here?
What do you think is the underlying rhythm?


Cath Lab: Radiation Protection in Cath Lab - from Medscape


Heart Transplant: Single Lung Physiology

Lamour, JM, et al. (from Columbia, NY)
J Heart Lung Transplant 2004;23:948-53

11 patients with single lung physiology from congenital heart disease.
TOF with absent LPA - 4,
Single Ventricle s/p Classic Glenn - 7 (Absent LPA 1, Severe LPA hypertension 6)

Cause of LPA hypertension in the 6 pts:
Pulmonary vein stenosis 3, Waterston shunt 1 and AP collateral 2.

Preop. mean RPA pressure:
TOF patients - 29 ± 10 mmHg
Classic Glenn patients - 15 ± 4 mmHg

PA angiograms showed normal branch pattern of RPA.
Lung perfusion scan showed 80% flow to right lung in patients with LPA hypertension.

Age range at Heart Transplant: 9 - 43 yrs.

Early postop death 2 (Aortic rupture 1, Bleeding 1) - 82% operative survival.
Late death 1 (Rejection at 3 yrs)
8/11 are alive at 4 yrs.
LPA continuity was established in 6 pts: Post-op lung perfusion scan did not show increase in flow to LPA.


EKG: P wave

What is the typical morphology of P wave in V1?
What is the typical morphology of P wave in II?
Why are II & V1 the best leads to look for P wave?
Why is amplitude the criterion for RA enlargement, while duration is the criterion for LA enlargement?
What is MCL1 lead?

Echo: Descending aorta Doppler Pattern, s/p Repair of Coarctation

What wrong with the descending aortic flow pattern in the top panel?
Bottom 3 panels are other views from the same patient. Use all of them, before concluding on this case. 3 yr old s/p repair of coarctation at 1 month of age.


EKG: Narrow Complex Tachycardia in a neonate

Newborn transferred from another facility.
Intractable tachycardia, now on Amiodarone, Procainamide and Digoxin.
Plan is to change Digoxin to Beta-blocker.
Panel 1 (below) - Telemetry print-out of tachycardia breaking to WPW pattern (*)
Panel 2 (above): WPW pattern changing to Normal AV conduction (*)

Panel 3 (above): 12-lead EKG during tachycardia

Echo: What is shown by black arrow?

Clue: This is a 3 month old baby who has had Right modified BT shunt for DORV, d-TGA, Pulmonary atresia. Aortic arch is shown from suprasternal notch view.


Medications: IV Propranolol dose, a word of caution!

Propranolol - Oral dose is 2-6 mg/kg/day
But, the IV dose is 0.01 - 0.1 mg/kg/dose - slow IV over 10 minutes. Max. 1 mg (infants) & 3 mg (children), 5 mg (adults - to be given as 1 mg alliquots slow IV x repeat every 5 min)

IV dose is much lower than oral dose because of the extensive first-pass metabolism in the liver. Therefore, bioavailability of orally-administered Propranolol is much lower (30-40% of administered dose, higher in Down's syndrome).

Beware, IV Propranolol is a frequently over-dosed medication by doctors! (Mostly due to ignorance). This occurs mostly when a patient is receiving oral Propranolol and is NPO for some reason. Someone (a physician) writes the same oral dose to be given IV. Generally, overdosed approx. 10-fold!


Interpret this: EKG - Rhythm strip

12 yr old, athletic girl.
Irregular heart beat was noted during routine examination by PCP.
Rhythm strip above & 12-lead below


Cath Lab: Pressure Trace, Giant a wave in RA

From a patient with PA-IVS: (? Moss & Adams.)

Above image of "Cannon a wave" is from Proctor Harvey collection available online from here.

And, a video by Paul Wood (Univ. of London, 1958)