title: Pulmonary sequestration of cardioplegia administered via the aortic root during aortocoronary bypass surgery.
abstract: A semi-quantitative method was devised of tracing blood flow through the heart and lungs at the time of cardioplegia delivery and circulatory arrest of the heart during coronary artery bypass graft surgery (CABG). There were no previous studies confirming or disputing an accepted 'observation' by cardiac surgeons that cardioplegia solution does enter the lung parenchyma during cardiopulmonary bypass (CPB). This study was conducted as part of a larger (n = 142) double-blind, randomised, controlled, clinical research study.
  
  
  OBJECTIVE
  The objective was initially to establish the efficacy of measures to prevent cardioplegia entering the lungs and, subsequently, to determine whether cardioplegia indeed circulates through the lung parenchyma or merely accumulates and 'pools'.
  
  
  METHODS
  A prospective study on 20 consecutive patients (5 per group) admitted for CABG was made. Technetium (Tc-99m), a radioactive isotope, was added to the cold blood cardioplegia solution prior to cardioplegia delivery in order to track flow of cardioplegia solution. An independent nuclear medicine radiographer measured the samples with the use of a 'Curimentor' dose calibrator for presence and quantity of radiation in the samples. Decay was factored into the results. The Tc-99m tracer samples were also analysed using Gamma Acquisition and Analysis on the Genie 2000vdm Well Counter to confirm the presence and quantity of Tc-99m.
  
  
  RESULTS
  In the four groups, it was confirmed that the pulmonary artery (PA) vent is 90-100% effective in retrieving any cardioplegia solution not drained by the atriocaval cannulae.
  
  
  CONCLUSIONS
  The PA vent is effective in preventing cold blood cardioplegia solution from entering the lungs. Any cardioplegia that does enter the lung parenchyma during CPB circulates through the lungs and can be retrieved by a vent in the left atrium. This method may be useful in other studies that require investigation.
authors: Department of Surgery, Nelson Mandela School of Medicine, University of Kwa-Zulu Natal, South Africa. tamra@dbn.stormnet.co.za
authors: Tamra
authors: T
authors: McFarlane
authors: Robert
authors: R
authors: Kleinloog
authors: Margot
authors: M
authors: Bennett
mesh_terms: D000368:Aged; D001011:Aorta / Q000000981:diagnostic imaging; D002314:Cardioplegic Solutions / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics*; D003080:Cold Temperature; D001026:Coronary Artery Bypass; D005260:Female; D006324:Heart Arrest, Induced / Q000009:adverse effects*; D006325:Heart Atria; D006349:Heart Valve Diseases / Q000601:surgery; D006801:Humans; D008168:Lung / Q000098:blood supply / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011651:Pulmonary Artery / Q000000981:diagnostic imaging; D011652:Pulmonary Circulation; D011877:Radionuclide Imaging; D013667:Technetium
chemical_list: D002314:Cardioplegic Solutions; D013667:Technetium