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A C T A M E D I C A M A R T I N I A N A 2 0 0 5 5/2 3
ASSESSMENT OF THE MECONIUM REMOVAL IN SURFACTANT VS.
SALINE-LAVAGED RABBITS WITH MECONIUM ASPIRATION
DANIELA MOKRÁ 1 , ANNA DRGOVÁ 2 , ANDREA CALKOVSKÁ 1
Department of Physiology 1 and Department of Medical Biochemistry 2 , Comenius University,
Jessenius Faculty of Medicine, Martin, Slovakia
A b s t r a c t
Background and aim: Objective quantification of the amount of removed meconium is an important indicator of efficacy
of approaches potentially improving meconium clearance from the lungs. The goal of this study was to assess the
amount of removed meconium by surfactant vs. saline lavage in rabbits with meconium aspiration by spectrophotometry
and meconium-crit methods.
Methods: Adult rabbits were anesthetized, tracheotomized, paralyzed and conventionally ventilated. Human meconium
(25 mg/ml, 4 ml/kg b.w.) was instilled proportionally into the right and left lungs. When respiratory failure developed,
surfactant (Surf, n=7) or saline (Sal, n=7) lavage at a dose of 10 ml/kg b.w. in 3 portions was performed. Lavage
fluid was suctioned 1 and 5 min after the administration and meconium content in the lavage fluid was evaluated by
spectrophotometry and meconium-crit methods.
Results: Animals of both groups were given comparable amount of meconium. Surfactant lung lavage removed significantly
more meconium when evaluated by meconium-crit method (P0.05).
Conclusions: The discrepancy between the results estimated by spectrophotometry and meconium-crit methods
resulted from the different qualities evaluated by these two methods. Moreover, since water-soluble parts of meconium
were effectively removed by both saline and surfactant lavage, surfactant improved the clearance of cholesterol-soluble
fraction of meconium, too.
K e y w o r d s : meconium, lung lavage, rabbit
INTRODUCTION
Despite combined therapy, meconium aspiration syndrome (MAS) is one of the most severe
diseases in the term newborns. Aspiration of meconium causes obstruction of the airways, inactivation
of pulmonary surfactant, inflammation and pulmonary vasoconstriction, that often leads
to the respiratory failure.
Chemically, meconium can be extracted to the water-soluble (gastrointestinal enzymes, bile
acids, bilirubin etc.) and chloroform-soluble (free fatty acids, cholesterol, neutral lipids etc.) fractions
(1). Due to the high concentration of mucopolysaccharides, meconium is extremely adhesive
to the airway walls, and clearing procedures such as airway suctioning and physiotherapy
may be ineffective.
Lung lavage with diluted exogenous surfactant increased the meconium clearance from the
lungs in several experimental studies (2-6). Improvement in oxygenation and survival after the
surfactant lavage was found also in the newborns with MAS (7-9).
Although standardization of the lavage procedure in the terms of the number of lavages, volume
of the administered fluid, and concentration and type of surfactant until now have not
inferred to the final conclusion, amount of the removed meconium became an important indicator
of efficacy of approaches potentially improving meconium clearance from the lungs.
Whereas the previous use of the methods objectively quantifying the meconium content in the
recovered lavage fluid led to the controversial results, the goal of this study was to assess the
amount of removed meconium by surfactant vs. saline lavage in rabbits with meconium aspiration
by spectrophotometry and meconium-crit methods.
Address for correspondence:
Daniela Mokrá, MD, PhD, Department of Physiology, Comenius University, Jessenius Faculty of Medicine,
Malá Hora 4, 037 54 Martin, Slovakia
tel: +421-43-4131426, fax: +421-43-4222260, e-mail: sevecova@jfmed.uniba.sk