Intensive Care Medicine

, Volume 34, Issue 7, pp 1216–1223

Elevated pulmonary dead space and coagulation abnormalities suggest lung microvascular thrombosis in patients undergoing cardiac surgery

  • Barry Dixon
  • Duncan J. Campbell
  • John D. Santamaria

DOI: 10.1007/s00134-008-1042-7

Cite this article as:
Dixon, B., Campbell, D.J. & Santamaria, J.D. Intensive Care Med (2008) 34: 1216. doi:10.1007/s00134-008-1042-7



Inflammation has been shown to trigger microvascular thrombosis. Patients undergoing cardiac surgery sustain significant inflammatory insults to the lungs and in addition are routinely given anti-fibrinolytic agents to promote thrombosis. In view of these risk factors we investigated if evidence of pulmonary microvascular thrombosis occurs following cardiac surgery and, if so, whether a pre-operative heparin infusion may limit this.


Double-blind randomised controlled trial.


Tertiary university affiliated hospital.


Twenty patients undergoing elective cardiac surgery.


Patients were randomised to receive a pre-operative heparin infusion or placebo. All patients were administered aprotinin.

Measurements and results

Pulmonary microvascular obstruction was estimated by measuring the alveolar dead-space fraction. Pulmonary coagulation activation was estimated by measuring the ratio of prothrombin fragment levels in radial and pulmonary arterial blood. Systemic tissue plasminogen activator (t-PA) levels were also assessed. In the placebo group cardiac surgery triggered increased alveolar dead-space fraction levels and the onset of prothrombin fragment production in the pulmonary circulation. Administration of pre-operative heparin was associated with a lower alveolar dead-space fraction (p < 0.05) and reduced prothrombin fragment production in the pulmonary circulation (p < 0.05). Pre-operative heparin also increased baseline t-PA levels (p < 0.05).


The changes in the alveolar dead-space fraction and pulmonary coagulation activation suggest that pulmonary microvascular thrombosis develops during cardiac surgery and this may be limited by a pre-operative heparin infusion.


Cardiopulmonary bypassCoagulationFibrinolysisInflammationThrombosis

Supplementary material

134_2008_1042_MOESM1_ESM.doc (46 kb)
Electronic Supplementary Material (DOC 46K)

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • Barry Dixon
    • 1
  • Duncan J. Campbell
    • 2
  • John D. Santamaria
    • 1
  1. 1.Intensive Care UnitSt. Vincent’s HospitalMelbourneAustralia
  2. 2.St. Vincent’s Institute of Medical ResearchMelbourneAustralia