Myocardial Protection for correction of AV Canal Defect

Ron Angona, MS, CCP

University of Rochester Medical CenterRochester, NY

• None

Disclosures

• 2 y.o. w/ AV canal defect, Trisomy 21– Admitted from home

• Balanced canal, moderate atrial component with small ventricular component completely occluded by tricuspid valve

• Mild MR, cleft MV, nl LV fxn

– 85cm, 10 kg BSA 0.49 m2

– Bicaval cannulation– antegrade cardioplegia

Background

• Initial dose typically 40-60 mL/kg• 4:1 Blood:Crystalloid

– Crystalloid solution is Plasmalyte-A w/ 52.8 meq K+ added– Made in house by pharmacy– No additives– Single dose in 95% of cases

• Essentially all but ASO

– Up to 100 minute x-clamp times

• Arrest typically occurs at 5mL/kg

Myocardial Protection

• Cardioplegia initiated• Delayed arrest (mostly) occurred around 10 mL/kg

• Rapid investigation– Is the crystalloid bag opened?– Is the plegia cold?– Good root pressure– Ratio set correctly at 4:1– Correct tubing sizes

– Potassium?

Continued…

• Sample of crystalloid cardioplegia solution taken, run on ABG analyzer

• Concurrently, (at about ~20 mL/kg) surgeon asks:

“Did you put potassium in the cardioplegia?”

Run a Sample

• K+ in plegia bag should be out of range– Actual value of sample was 4.6 mmol/L

• Call another perfusionist– Double check observations

• Plegia dose finishes at 55 mL/kg– Surgeon icing heart, concerned

• Sample off plegia heat exchanger (post-mix), completed after dose finished, showed HCT 14%, K+ 3.8.– Pt. K+ at this time was 3.8, K+ in Normosol is 4.6…

Results

• Sample run from another bag of plegia showed a k+ of 15, as would be expected

• Stuck needle in line when we took back the plegia, K+ again was 3.8– We questioned the composition of the blood of the top of

the heat exchanger– Early Resumption of Activity

• Pharmacist called• Plegia bag sequestered, samples sent to pharmacy

More Samples…

• Pharmacy verified the mistake that evening– Several bags effected no others had been used

• Pump time 1:36, x-clamp 1 hour (55 min ischemic time)

• Normal resumption of activity• Pt. weaned from CPB on expected regiment of Epi

(0.03), Dopa (3), Milrinone (0.5)• To PICU intubated

Findings, Results

• Extubated following morning 9am to NC 2L– Lactate nl, Epi + Dopa off by that point– Peak troponin 0.36, lactate 1.8,

• POD 2 – milrinone off, ambulates, PO diet– CK Peak 2090, CKMB 44.9

• Sedated ECHO POD 9 – nothing significant• Delayed discharge (POD 10) d/t continued drainage

from MT tube– Uneventful otherwise

• 1 month f/u – no limitations, no cardiac meds

Post Op

• Could have added more K+– Time constraint

• Second dose of cardioplegia• Plegia now made in OR by perfusion

– Mix is tested prior to clamping, administration • Temporary?• Liability?

Process Improvement / Fall out

• Sentinel events can make you question even your most basic assumptions

• Very fortunate patient was unharmed

• How important is cardioplegia composition in PEDIATRIC cardiac surgery?

– Cardioplegia in Pediatric Cardiac Surgery: Do We Believe in Magic? Doenst T

Ann Thorac Surg 2003;75:1668-77

Conclusion