Blood cardioplegia provides superior protection in infant cardiac surgery.
BACKGROUND
We hypothesized that blood cardioplegia preserves myocardial metabolism and function more effectively than St Thomas' crystalloid cardioplegia in infant cardiac surgery.


METHODS
Thirty infants with atrioventricular septal defects were randomly allocated to either blood or crystalloid intermittent cold (4 degrees C) cardioplegia. Arterial and coronary sinus blood was analyzed for lactate and oxygen. Cardiac output (thermodilution) and left ventricular function (echocardiography) were evaluated.


RESULTS
The lactate concentration in coronary sinus blood early after bypass was significantly higher after crystalloid cardioplegia than after blood cardioplegia (2.1 +/- 0.3 vs 1.3 +/- 0.1 mmol/L, p = 0.006), with a significant myocardial release of lactate after crystalloid but not after blood cardioplegia. Oxygen extraction (arterial-coronary sinus O2 content) was higher early after crystalloid cardioplegia (3.02 +/- 0.13 vs 2.35 +/- 0.22 mmol/L, p = 0.01), possibly reflecting a difference in oxygen debt. The cardiac index was higher after blood cardioplegia (4.9 +/- 0.3 vs 4.0 +/- 0.3 L/min(-1)/m(-2), p = 0.04) and echocardiographic grading of left ventricular function was better (4.1 +/- 0.17 vs 3.5 +/- 0.22 arbitrary units, p = 0.046).


CONCLUSIONS
This study indicates that blood cardioplegia preserves myocardial metabolism and function more effectively than crystalloid cardioplegia in infant cardiac surgery. The clinical significance of this finding is uncertain, but the more than 20% increase in cardiac index in the critical phase during weaning from bypass may be advantageous.
Amark
Kerstin
K
Department of Pediatric Cardiology and Pediatric Anesthesia and Intensive Care, The Queen Silvia Children's Hospital, Göteborg, Sweden. kerstin.amark@vgregion.se
Berggren
Håkan
H
Björk
Kerstin
K
Ekroth
Annica
A
Ekroth
Rolf
R
Nilsson
Krister
K
Sunnegårdh
Jan
J
D015415:Biomarkers / Q000097:blood; D001769:Blood; D002302:Cardiac Output; D006348:Cardiac Surgical Procedures / Q000379:methods; D002314:Cardioplegic Solutions / Q000627:therapeutic use*; D004452:Echocardiography; D005260:Female; D006324:Heart Arrest, Induced / Q000295:instrumentation* / Q000379:methods*; D006343:Heart Septal Defects / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D007223:Infant; D019344:Lactic Acid / Q000097:blood; D008297:Male; D009206:Myocardium / Q000378:metabolism; D017680:Potassium Compounds / Q000627:therapeutic use; D016896:Treatment Outcome; D016277:Ventricular Function, Left
D015415:Biomarkers; D002314:Cardioplegic Solutions; D017680:Potassium Compounds; C018369:potassium cardioplegic solution; D019344:Lactic Acid