Introduction Meconium aspiration occurs in predominantly term or post- term babies who have suffered from intra-uterine asphyxia. The lung disease that follows the aspiration of meconium could have many causes including mechanical obstruction of the airways, chemical pneumonitis [18], surfactant in- hibition [15] and asphyxial damage. That surfactant dys- function is of some importance has been suggested by an- imal studies showing improved lung function after surfac- tant treatment [16, 17]. Two recent clinical reports suggest that bovine surfactant has beneficial effects in babies with meconium aspiration syndrome [1, 7]. We report the results of a retrospective case series of 54 infants with severe meconium aspiration syndrome treated with a porcine surfactant, Curosurf between April 1988 and June 1995. Methods Questionnaires were sent out to paediatricians at hospitals known to be using Curosurf to obtain information on the treatment of in- fants with meconium aspiration syndrome. Meconium aspiration syndrome was defined using the following criteria: (1) thick meco- nium-stained amniotic fluid or meconium visualised below the cords and (2) a chest radiograph consistent with meconium aspira- tion syndrome reported by a radiologist [7]. Fifty-one replies were Abstract This study is based on clinical data from a retrospective se- ries of 54 infants with meconium as- piration syndrome treated with porcine surfactant at a median age of 14 h (range 1–176 h). Median arterial/ alveolar oxygen tension ratio (a/A PO 2 ratio) before treatment was 0.08 (range 0.02–0.23) and oxygenation index 25 (range 6–110). After treat- ment with surfactant at an initial dose of 50–200 mg/kg there was a modest but statistically significant increase in a/APO 2 ratio associated with a re- duction of oxygenation index. Ten (18%) babies showed a 3–4 fold in- crease in a/APO 2 ratio within 1–2 h of treatment. Twenty-four (44%) ba- bies showed little or no response by 1–2 h with the remaining infants showing modest improvement in oxygenation. One third of babies re- quired repeated doses of surfactant. Twenty-eight day survival was 81%, with two babies requiring extracor- poreal membrane oxygenation. Key words Newborn · Meconium aspiration syndrome · Surfactant Abbreviations a/APO 2 arterial/ alveolar oxygen tension ratio · ECMO extracorporeal membrane oxygenation · FiO 2 fractional inspired oxygen · MAP mean airway pressure · OI oxygenation index · PIP peak inspiratory pressure Conclusion Natural surfactant treatment of severe meconium aspi- ration may prove to be a useful in- tervention and randomised con- trolled clinical trials should be un- dertaken. NEONATOLOGY Eur J Pediatr (1996) 155 : 1047–1051 © Springer-Verlag 1996 Henry L. Halliday Christian P. Speer Bengt Robertson on behalf of the Collaborative Surfactant Study Group Treatment of severe meconium aspiration syndrome with porcine surfactant Received: 2 November 1995 Accepted: 8 February 1996 H. L. Halliday Royal Maternity Hospital, Grosvenor Road Belfast BT12 6BB, Northern Ireland Tel.: 01232 894687 Fax: 01232 236203 H. L. Halliday Department of Child Health, The Queen’s University of Belfast, Northern Ireland C. P. Speer Department of Neonatology, University Children’s Hospital, Tubingen, Germany B. Robertson Division of Experimental Perinatal Pathology, Department of Women and Child Health, Karolinska Institute, Stockholm, Sweden