title: A trial of nebulised heparin to limit lung injury following cardiac surgery.
abstract: Cardiac surgery with cardiopulmonary bypass triggers an acute inflammatory response in the lungs. This response gives rise to fibrin deposition in the microvasculature and alveoli of the lungs. Fibrin deposition in the microvasculature increases alveolar dead space, while fibrin deposition in alveoli causes shunting. We investigated whether prophylactic nebulised heparin could limit this form of lung injury. We undertook a single-centre double-blind randomised trial. Forty patients undergoing elective cardiac surgery with cardiopulmonary bypass were randomised to prophylactic nebulised heparin (50,000 U) or placebo. The primary endpoint was the change in arterial oxygen levels over the operative period. Secondary endpoints included end-tidal CO₂, the alveolar dead space fraction and bleeding complications. We found nebulised heparin did not improve arterial oxygen levels. Nebulised heparin was, however, associated with a lower alveolar dead space fraction (P <0.05) and lower tidal volumes at the end of surgery (P <0.01). Nebulised heparin was not associated with bleeding complications. In conclusion, prophylactic nebulised heparin did not improve oxygenation, but was associated with evidence of better alveolar perfusion and CO₂elimination at the end of surgery.
authors.affiliation: Department of Critical Care, St.Vincent's Hospital, Melbourne, Victoria.
authors.forename: B
authors.initials: B
authors.lastname: Dixon
authors.affiliation: Department of Critical Care, St.Vincent's Hospital, Melbourne, Victoria.
authors.forename: R
authors.initials: R
authors.lastname: Smith
authors.affiliation: Department of Critical Care, St.Vincent's Hospital, Melbourne, Victoria.
authors.forename: J D
authors.initials: JD
authors.lastname: Santamaria
authors.affiliation: Department of Critical Care, Barwon Health University Hospital, Geelong, Victoria.
authors.forename: N R
authors.initials: NR
authors.lastname: Orford
authors.affiliation: Department of Critical Care, Barwon Health University Hospital, Geelong, Victoria.
authors.forename: B J
authors.initials: BJ
authors.lastname: Wakefield
authors.affiliation: Department of Critical Care, Barwon Health University Hospital, Geelong, Victoria.
authors.forename: K
authors.initials: K
authors.lastname: Ives
authors.affiliation: Department of Critical Care, Barwon Health University Hospital, Geelong, Victoria.
authors.forename: R
authors.initials: R
authors.lastname: McKenzie
authors.affiliation: Department of Cardiothoracic Surgery, Barwon Health University Hospital, Geelong, Victoria.
authors.forename: B
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Department of Epidemiology and Preventive Medicine, Monash University and School of Medicine, Deakin University, Melbourne, Victoria.
authors.forename: C H
authors.initials: CH
authors.lastname: Yap
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage*; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D004311:Double-Blind Method; D005260:Female; D006493:Heparin / Q000008:administration & dosage*; D006801:Humans; D055370:Lung Injury / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D009330:Nebulizers and Vaporizers
chemical_list: D000925:Anticoagulants; D006493:Heparin
keywords: acute lung injury; cardiac surgery; fibrin; heparin; microvascular thrombosis