Ines de Mir

New reference ranges for interpreting forced expiratory manoeuvres in infants and implications for clinical interpretation: a multicentre collaboration

The raised volume rapid thoracoabdominal compression (RVRTC) technique is commonly used to obtain full forced expiratory manoeuvres from infants, but reference equations derived from ‘in-house’ equipment have been shown to be inappropriate for current commercially available devices. Aim To explore the impact of equipment differences on RVRTC outcomes, derive robust equipment-specific RVRTC reference ranges and investigate their potential clinical impact on data interpretation. Method RVRTC data from healthy subjects using Jaeger BabyBody or the ‘Respiratory Analysis Software Program, RASP’ systems were collated from four centres internationally. Data were excluded if gestational age <37 weeks or birth weight <2.5 kg. Reference equations for RVRTC outcomes were constructed using the LMS (lambda–mu–sigma) method, and compared with published equations using data from newborn screened infants with cystic fibrosis (CF). Results RVRTC data from 429 healthy infants (50.3% boys; 88% white infants) on 639 occasions aged 4–118 weeks were available. When plotted against length, flows were significantly higher with RASP than Jaeger, requiring construction of separate equipment-specific regression equations. When comparing results derived from the new equations with those from widely used published equations based on different equipments, discrepancies in forced expiratory volumes and flows of up to 2.5 z-scores were observed, the magnitude of which increased with age. According to published equations, 25% of infants with CF fell below the 95% limits of normal for FEV0.5, compared with only 10% when using the new equations. Conclusions Use of equipment-specific prediction equations for RVRTC outcomes will enhance interpretation of infant lung function results; particularly during longitudinal follow-up.

Whole-lung lavage in a toddler. Technical challenges and solutions

Introduction: Pulmonary alveolar proteinosis is a rare respiratory disease whose main treatment is the whole-lung lavage. This could be a challenging procedure in small children. Objective: The aim of this report is to show our experience coping with a 21-month-old girl with pulmonary alveolar proteinosis, who needed a whole-lung lavage due to persistent hypoxemia. Case report: Our patient was a healthy girl until she was 7 months, when she was diagnosed with myeloblastic leukemia. At the age of 13 months, a hematopoietic stem cell transplant was undergone after no response to chemotherapy. After a sepsis when she was 20 months, she had respiratory distress and hypoxemia that persisted for more than 2 weeks, so a chest CT was ordered; it showed bilateral ground-glass opacities. A bronchoalveolar lavage plus a pulmonary biopsy were undergone, confirming the diagnosis of pulmonary alveolar proteinosis. A whole-lung lavage was done, using simultaneously 2 endotracheal cuffed tubes: one (3.5 mm diameter) placed in the trachea to ventilate one lung and another of 3 mm (modified to make it longer) to instill heated saline into the bronchus to perform the lavage. This procedure was done in 2 different days: firstly on the right lung and secondly on the left one, with a total of 2.5 L saline in every lung. The procedure was well tolerated with a good clinical response, and the girl was discharged 2 weeks later. Conclusions: We found a solution to a challenging situation which is to perform a whole-lung lavage in a toddler by placing concurrently 2 tubes into the airway. We believe it is possible to perform a whole-lung lavage in small children despite not having specific double-lumen tubes for children aged below 8 years.