title: The "tube-in-tube" circuit: a new method for delivering cold blood cardioplegia in neonates and small infants.
abstract: OBJECTIVE
  To conceive a method to deliver cold blood cardioplegia in neonates and young infants.
  
  
  METHODS
  The "tube-in-tube" circuit consists of a 3-mm line (bloodline) which is inserted inside a 1/2 -in tube where cold water flows continuously (waterline). This circuit includes a filling volume of 18 mL of static prime and 15 mL for the collecting line (pump raceway). Several temperature samples were taken at different blood flows from 20 to 100 mL/min.
  
  
  RESULTS
  Temperatures (in °C) at the needle tip were significantly lower when using the tube-in-tube cooling circuit if compared to standard cardioplegia circuit at flows up to 60 mL/min.
  
  
  CONCLUSIONS
  The tube-in-tube circuit proved to be an effective strategy for low-flow cardioplegia delivery (<60 ml/min), which is particularly useful in neonates and young infants; the lower is the flow, the better is the cooling effect on the cardioplegia.
authors.affiliation: Department of Cardiac, Thoracic and Vascular Sciences, Cardiovascular Perfusion Unit, University of Padua, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Zanella
authors.forename: Vladimiro L
authors.initials: VL
authors.lastname: Vida
authors.forename: Massimo A
authors.initials: MA
authors.lastname: Padalino
authors.forename: Giovanni
authors.initials: G
authors.lastname: Stellin
mesh_terms: D002314:Cardioplegic Solutions / Q000008:administration & dosage*; D003080:Cold Temperature; D004867:Equipment Design; D006324:Heart Arrest, Induced / Q000295:instrumentation / Q000379:methods*; D006330:Heart Defects, Congenital / Q000601:surgery; D006801:Humans; D007223:Infant; D007231:Infant, Newborn
chemical_list: D002314:Cardioplegic Solutions
keywords: cardiopulmonary bypass (components; configuration); congenital heart surgery; myocardial protection; neonate