ICU: Postoperative AV block - Recovery

Study period: 1991-4. Boston Children's Hospital. n=2698 surgeries (73% on bypass).

Overall incidence of AV block was 3% (n=54).

Common diagnoses associated with development of AV block were VSD, Tetralogy, LVOTO repair, L-TGA and others. 

32 recovered conduction in 30 days after surgery (Graph below shows the postop. day at which conduction recovered in these 32 patients). 

9 did not recover conduction in 30 days after surgery. 

Weindling SN., et al. Duration of complete atrioventricular block after congenital heart surgery. Am J Cardiol 1998;82:525-527.

ICU: Arterial Line Artifact - "Standing Wave"

Pardon the poor quality images.

Newborn, s/p Norwood procedure.

Upper panel shows arterial pressure traces from 2 different lines - Right radial arterial (Red) and Umbilical arterial lines (White). There is a "standing wave" or "fling" in the red trace. This is secondary to being a small/distal vessel, smaller catheter, and state of peripheral vascular tone (vasoconstricted state).

Lower panel shows the same patient, approx. 30 min after the loading dose of Milrinone. Presumably, there is adequate vasodilation of the peripheral artery that the "standing wave" or "fling" is no longer evident or not as prominent as before!

(Click on the images to enlarge)

ICU - Antibiotics

ICU Monitor: Freeze Frame Function to analyze traces

(Click on the image to enlarge)

When you want to analyze a trace i.e. identify the waves in a CVP trace, you can use the "Freeze" function. The "frozen" traces have a vertical, dotted line at every second. These lines coincide between traces, enabling you compare the EKG trace, Arterial trace and CVP trace. These can be used to identify the waves in CVP trace.

In this example, CVP trace has taller v wave compared to a wave. v wave corresponds to the peak of arterial trace - i.e. ventricular systole. Note: Arterial ejection peak is somewhat delayed from the electrical systole (QRS complex) due to the delay between electrical systole and mechanical systole and a slight delay in arrival of the peak of arterial trace to the femoral artery and right radial artery. (In this panel, trace labelled ABP is right radial artery line and the trace labelled ART is left femoral line).

Quiz: EKG, Postop. Repair of AVSD

5 mo old, Postop. day 3 after AVSD repair.
(Click on the image to enlarge)

1) What is different between first half and second half of the EKG trace?

2) What type of pacing is being done?

3) What is the pacing rate?

4) What is the atrial rate?

5) What is the native ventricular rate?

6) What is the diagnosis for the underlying rhythm?

Cardiopulmonary interactions

From Cardiac ICU book by Anthony Chang.

Pleural effusion after Fontan Operation

Am J Cardiol 2005;96:130-3
Millwaukee. 2000-2005, n=25 (on protocol) vs. Historic controls from 1997-2000 (n=33). Median duration of pleural effusion decreased (6 days vs. 15 days).

Protocol:
80% maintenance fluids
Lasix 1 mg/kg/dose Q8 hrs, changed to Diuril + Spironolactone Q12 hrs when PO intake starts
Captopril when PO intake starts
Nasal cannula oxygen, at least 0.5 LPM
Low fat diet (30% calories from fat)

(Nitric oxide/Sildenfil)

Other papers:
Curr Opin Pulm Med 2010;16:392-6 (by E. Austin III) - summarizes several recent studies. No signficant conclusions. Highlights the uncertainty of etiology and aproach.

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.

ICU: DDD pacemaker

This is 2 year old postop. patient with DDD pacemaker. What a sinking feeling one gets upon seeing this! (Absolutely no capture of either the atrium or the ventricle).
Click on the image for a larger image.

EKG: Sinus bradycardia with Junctional Escape

4 yr old boy, s/p Ebstein's repair with bioprosthetic valve in tricuspid valve position. Pierre Robin syndrome. Intermittent stridor. Possible vocal paralysis. (Click on the image to enlarge)

Narrow complex tachycardia - Re-entry type

2 yr old, 10 kg. Unbalanced AV septal defect. s/p Takedown of Glenn Operation. Postop. day 5.
Sequence of events during management of tachyarrhythmia:

On Epinephrine, Dobutamine and Milrinone infusions, Digoxin maintenance dose.
Abrupt increase in heart rate from 111/min to 165/min.
Initial diagnosis of SVT. Adenosine (1 mg) administration reveals multipe P waves.
Atrial Flutter is treated with synchronized DC cardioversion (5 Joules).

(Click on the image to enlarge)

Quiz: Temporary Pacemaker

2 year old, s/p heart surgery for complex congenital heart disease - having a difficult postoperative course. Upper panel shows a problem with pacemaker. This h been corrected in the lower panel.
1) What is the pacemaker problem in the upper panel? Can you guess the pacemaker mode in the upper panel?
2) What adjustments in the pacemaker will rectify the problem?
3) Lower panel (recorded 2 hrs later): How is the pacemaker functioning now? What are the current settings in the pacemaker i.e. Mode, Rate & AV interval setting?

(Click on the image to see a larger image)

Systolic timings - EKG, Pressure Traces...

(Image and information from Principles of Clinical Electrocardiography by Mervin Goldman 11th ed. 1982. p.39)

Relationship of electrical to mechanical events.
1 - Electromechanical systole
2 - LV Ejection time (LVET)
3 - Pre-ejection period (PEP)
Note: Dicrotic notch in aortic pressure wave corresponds to aortic valve closure. Portion of arterial waveform after dicrotic notch represents peripheral vascular recoil and reflection wave.

ICU: Pacemaker Settings Record Sheet

For bedside use Click here for a copy

ICU: Permanent Pacemaker

3 yr old, Heterotaxy, s/p Fontan procedure. s/p Permanent pacemaker for sick sinus syndrome. Develops sepsis, returns from percutaneous drainage of pyonephrosis. Dexmedetomidine and ketamine were used for this short interventional radiology procedure. After return to ICU, the child has the following trace on the monitor. Interpret.

1) What is the underlying rhythm?
2) What is the pacemaker set at? Guess the mode and rate.
3) Is there native AV conduction? If yes, what is the native AV interval?
4) What is the AV interval for paced beats?
5) What is the pacemaker doing? What is the final assessment of this patient?
6) Why do the pacing spikes appear irregular?
7) How would you manage this patient? (Further studies tests and evaluations are necessary to make an assessment and management).

(Click on the image to enlarge)

CVP trace: Junctional rhythm vs. Sinus Rhythm

6 week old, s/p Repair of TAPVR.
Upper panel - A-paced at 130 bpm.
Lower panel - No pacing.
Diagnosis is clear from EKG trace itself.
Notice the difference in waveform in CVP trace between the two panels. Name the waves in CVP trace. Which is the prominent wave in CVP in the lower panel (in junctional rhythm).
Also, notice the change in BP between the two panels. (Time display at the right lower corner indicates that the two panels were recorded 1 minute apart from each other). Explain the 2 reasons for the lower BP while in junctional rhythm.

ICU: Postop Fontan

3 yr old, s/p Fontan procedure, Postop. 12 hrs.
Comment on the hemodynamic status of this patient based on the monitor display.

CVP trace: PA-IVS

3-month old, PA-IVS, s/p BT shunt only as newborn.

Now, admitted for treatment of pneumonia.
1) Name the prominent wave in CVP trace: Is it "tall" 'a' wave or "tall" 'v' wave?
2) What does it signify if the "tall" wave is 'a' wave?
3) What does it signify if the "tall" wave is 'v' wave? (If it is tall 'v' wave, an echo finding will confirm it. What echo finding is it?)







This is an EKG from the same patient. Pardon the artifacts.

ICU: Where is the tip of this PA line?

ICU: What's wrong with this picture...

6-mo old. s/p Complete AVSD repair. Immediate postop. Just arrived from operating room.

Hint: The anomaly is the relationship between LA pressure and PA pressure.
Panel 1 - Has a problem/mistake. (Pardon the shaken image)
Panel 2 - The problem/mistake has been rectified.