title: Platelet Functions in Cardiopulmonary Bypass Surgery.
abstract: BACKGROUND
  Haemorrhage after Cardio Pulmonary Bypass (CPB) Surgery is a well recognised complication that leads to significant morbidity and mortality. The incidence varies between 5-25% depending upon the clinical situation. Several factors are implicated as causative but none have been precisely proved.
  
  
  METHODS
  Our study was an attempt to evaluate the haemostatic defect with particular reference to platelet function abnormalities during cardio pulmonary bypass surgery, in order to reduce the morbidity and mortality associated with post CPB haemorrhage. Flow cytometric evaluation of different platelet glycoproteins like GPIb/IX, GPIIb/IIIa and GMP-140 was done.
  
  
  RESULTS
  The marker expression showed deregulation during surgery which returned to base after bypass was terminated. In contrast, the cases with bleeding showed significant variation. P-Selectin (GMP 140) expression decreased progressively till 3(rd) post-operative day showing lack of activation of platelets in cases of severe bleeding.
  
  
  CONCLUSIONS
  Longer duration of CPB initiates plasmin generation through heparin, which raises the PAI-1-tPA complex and thereby down regulating the functions of platelets. This suggests a link between duration of CPB, bleeding, platelet dysfunction and fibrinolysis. Hence serial estimations of the levels of GMP-140 and tPA can predict severe bleeding.
authors.affiliation: Ex-Associate Professor, Department of Pathology, Armed Forces Medical College, Pune.
authors.forename: S J
authors.initials: SJ
authors.lastname: Varghese
authors.affiliation: Senior Advisor(CT Surgery), Military Hospital (Cardio Thoracic Centre) Pune.
authors.forename: M K
authors.initials: MK
authors.lastname: Unni
authors.affiliation: Ex-Classified Specialist (Anaesthesiology) Military Hospital (Cardio Thoracic Centre) Pune.
authors.forename: N
authors.initials: N
authors.lastname: Mukundan
authors.affiliation: Director General Medical Services(Army), Army Headquarters, New Delhi.
authors.forename: Ramji
authors.initials: R
authors.lastname: Rai
keywords: CardioPulmonary Bypass; Platelet dysfunction; flowcytometry; haemorrhage; platelet glycoproteins