Three-dimensional ultrasound fetal lung volumes and infant respiratory outcome: a prospective observational study M Prendergast, a GF Rafferty, a M Davenport, b N Persico, c J Jani, d K Nicolaides, c A Greenough a a Division of Asthma, Allergy and Lung Biology, MRC and Asthma UK Centre in Allergic Mechanisms of Asthma, King’s College London, London, UK b Department of Paediatric Surgery and c Harris Birthright Fetal Assessment Unit, King’s College Hospital, London, UK d Department of Obstetrics and Gynaecology, University Hospital Brugmann, Brussels, Belgium Correspondence: Prof A Greenough, 4th Floor Golden Jubilee Wing, King’s College Hospital, Denmark Hill, London SE5 9RS, UK. Email anne.greenough@kcl.ac.uk Accepted 23 November 2010. Published Online 4 February 2011. Objective To determine if fetal lung volumes (FLVs), determined by three-dimensional rotational ultrasound and virtual organ computer-aided analysis software (vocal), correlated with neonatal respiratory outcomes in surviving infants who had a high risk [fetuses with congenital diaphragmatic hernia (CDH)], lower risk [fetuses with anterior wall defects (AWDs)] and no risk (controls) of abnormal antenatal lung growth. Design Prospective observational study. Setting Tertiary fetal medicine and neonatal intensive care units. Population Sixty fetuses (25 with CDH, 25 with AWDs and ten controls). Methods FLVs were measured and expressed as the percentage of the observed compared with the expected for gestational age. Main outcome measures Neonatal respiratory outcome was determined by the duration of supplemental oxygen, mechanical ventilation and dependencies, and assessment of lung volume using a gas dilution technique to measure functional residual capacity (FRC). Results The infants with CDH had lower FLV results than both the infants with AWDs (P = 0.05) and the controls (P < 0.05). The infants with CDH had longer durations of mechanical ventilation (P < 0.001) and supplementary oxygen (P < 0.001) dependence, compared with infants with AWDs. The infants with CDH had a lower median FRC than both the infants with AWDs (P < 0.001) and the controls (P < 0.001). FLV results correlated significantly with the durations of dependency on ventilation (r = )0.744, P < 0.01) and oxygen (r = )0.788, P < 0.001), and with FRC results (r = 0.429, P = 0.001). Conclusions These results suggest that FLVs obtained using three-dimensional rotational ultrasound might be useful in predicting neonatal respiratory outcome in surviving infants who had varying risks of abnormal lung growth. Larger and more comprehensive studies are needed to clarify the role that lung volume measurements have in assessing lung function and growth. Keywords Anterior wall defect, congenital diaphragmatic hernia, fetal lung volume, three-dimensional ultrasound. Please cite this paper as: Prendergast M, Rafferty G, Davenport M, Persico N, Jani J, Nicolaides K, Greenough A. Three-dimensional ultrasound fetal lung volumes and infant respiratory outcome: a prospective observational study. BJOG 2011;118:608–614. Introduction Pulmonary hypoplasia, the result of abnormal antenatal lung growth, can occur as a primary anomaly, but more usually is the consequence of disorders that result in a reduction in fetal breathing movements, intrathoracic space or amniotic fluid volume. In the most severely affected there is a high mortality rate, but in survivors there is a spectrum of neonatal respiratory outcomes, from tachyp- noea in infancy to chronic oxygen dependency and lung function abnormalities, with exercise intolerance even in adolescence. 1,2 Postnatal therapy of pulmonary hypoplasia is only supportive, but antenatal interventions aimed at improving lung growth are becoming available. 3 It is, therefore, important that the magnitude of any abnormal antenatal lung growth is accurately diagnosed so that par- ents can be fully counselled and antenatal interventions appropriately used. A variety of methods have been used to assess whether there is abnormal antenatal lung growth. Reference ranges 608 ª 2011 The Authors BJOG An International Journal of Obstetrics and Gynaecology ª 2011 RCOG DOI: 10.1111/j.1471-0528.2010.02841.x www.bjog.org Fetal medicine