title: Using Measurements of Shunt and Ventilation-to-Perfusion Ratio to Quantify the Severity of Bronchopulmonary Dysplasia.
abstract: BACKGROUND
  Classifying the severity of bronchopulmonary dysplasia (BPD) by continuous numerical variables would facilitate follow-up of disease progression and quantified analysis of disease determinants.
  
  
  OBJECTIVE
  To non-invasively measure oxygenation impairment in BPD by the degree of right-to-left shunt, right shift of the oxyhaemoglobin dissociation curve and ventilation/perfusion (VA/Q) inequality and to explore their relation with clinical parameters.
  
  
  METHODS
  Prospective cohort study of 24 infants with a median (interquartile range, IQR) gestation of 25 weeks (24-27) and a birth weight of 0.70 kg (0.63-0.93), studied at 36 days (30-66), at a postmenstrual age (PMA) of 33 weeks (29-36). Inspired oxygen (FIO2) was varied to obtain three to five transcutaneous oxygen saturation (SpO2) values between 85 and 96%. Values of shunt, shift and VA/Q were obtained by plotting the paired data of SpO2 against FIO2 for each infant using a unique program. Right-to-left shunt, right shift of the oxyhaemoglobin dissociation curve and VA/Q were measured in infants born <32 weeks PMA receiving oxygen at 28 days.
  
  
  RESULTS
  The median (IQR) shunt was 8% (0.3-16.5), shift 14.5 kPa (10.9-19.4) and VA/Q 0.40 (0.30-0.48). Shunt, shift and VA/Q were significantly related to gestational age (GA) at birth, PMA at study, weight at study and weight gain per week.
  
  
  CONCLUSIONS
  Severity of pulmonary oxygenation impairment in BPD can be quantified at the cot-side by non-invasive measurement of shunt, shift and VA/Q. Low GA at birth, low weight at birth and at the time of study and impaired weight gain are significantly associated with the severity of oxygen-exchange impairment in infants with BPD.
authors.affiliation: Department of Obstetrics and Gynaecology, University of Cambridge, Cambridge, UK.
authors.forename: Theodore
authors.initials: T
authors.lastname: Dassios
authors.forename: Anna
authors.initials: A
authors.lastname: Curley
authors.forename: Colin
authors.initials: C
authors.lastname: Morley
authors.forename: Robert
authors.initials: R
authors.lastname: Ross-Russell
mesh_terms: D001724:Birth Weight; D001997:Bronchopulmonary Dysplasia / Q000175:diagnosis*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007223:Infant; D052577:Infant, Extremely Low Birth Weight; D062071:Infant, Extremely Premature; D007231:Infant, Newborn; D008297:Male; D010100:Oxygen / Q000097:blood; D011446:Prospective Studies; D012121:Respiration, Artificial; D012720:Severity of Illness Index
chemical_list: D010100:Oxygen