title: Pulmonary 99mTc-human serum albumin clearance and effects of surfactant replacement after lung lavage in rabbits.
abstract: OBJECTIVE
  Pulmonary clearance of technetium-labeled human serum albumin was measured in order to investigate whether the surfactant layer is a rate-limiting factor for the permeability of the alveolar-capillary membrane for 99mTc-labeled albumin.
  
  
  METHODS
  Prospective, randomized, controlled trial.
  
  
  METHODS
  Research laboratory.
  
  
  METHODS
  Nineteen white New Zealand adult rabbits.
  
  
  METHODS
  Three groups of rabbits were studied: group 1 animals received natural surfactant after lung lavage; group 2 animals underwent lung lavage only; and group 3 animals were not lavaged and served as an untreated, healthy control group. All animals were ventilated with high pressures.
  
  
  RESULTS
  99mTc-labeled albumin was nebulized into the inspiratory line of the breathing circuit with an air jet nebulizer. The clearance measurements were then immediately started. Gamma camera images were obtained in 1-min frames for 120 mins and stored in a 64 x 64 image matrix in a computer. In group 1 animals, surfactant restored blood gases to near normal, and all animals except one had bi-exponential clearance curves. The half-life of the fast compartment was 35.9 +/- 6.4 mins, and the half-life of the slow compartment was 847.5 +/- 143.5 mins. All group 2 animals also had bi-exponential clearance curves of the tracer (the half-lives of the fast and slow compartments were 14.6 +/- 6.7 and 459.8 +/- 167 mins, respectively). The half-lives of both the fast (p < .01) and slow (p < .01) components were significantly different between groups 1 and 2. Group 3 had a mono-exponential half-life of 580 +/- 225 mins.
  
  
  CONCLUSIONS
  The use of 99mTc-human serum albumin as a tracer molecule is possible and feasible. The clearance of this tracer is, in part, determined by the integrity of the pulmonary surfactant system, as it is with 99mTc-diethylenetriamine pentaacetate.
authors.affiliation: Department of Anesthesiology, Erasmus University Rotterdam, The Netherlands.
authors.forename: S J
authors.initials: SJ
authors.lastname: Verbrugge
authors.forename: D
authors.initials: D
authors.lastname: Gommers
authors.forename: J A
authors.initials: JA
authors.lastname: Bos
authors.forename: C
authors.initials: C
authors.lastname: Hansson
authors.forename: P
authors.initials: P
authors.lastname: Wollmer
authors.forename: W H
authors.initials: WH
authors.lastname: Bakker
authors.forename: B
authors.initials: B
authors.lastname: Lachmann
mesh_terms: D000818:Animals; D015824:Blood-Air Barrier / Q000187:drug effects / Q000502:physiology*; D006207:Half-Life; D006801:Humans; D008657:Metabolic Clearance Rate / Q000187:drug effects; D011446:Prospective Studies; D011663:Pulmonary Surfactants / Q000494:pharmacology*; D011817:Rabbits; D012121:Respiration, Artificial; D013668:Technetium Tc 99m Aggregated Albumin / Q000493:pharmacokinetics*; D007507:Therapeutic Irrigation
chemical_list: D011663:Pulmonary Surfactants; D013668:Technetium Tc 99m Aggregated Albumin