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Advances in infant and preschool lung function testing
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Oral Presentations / Paediatric Respiratory Reviews 13S1 (2012) S1–S50
PRL-11 Advances in infant and preschool lung function testing S. Ranganathan. Melbourne, Australia Background: Infant lung function tests are currently performed in more than 100 centres worldwide. Increasingly, centres in the AsiaPacific region are purchasing expensive and specialized equipment for this purpose. Equipment for testing preschool equipment is generally less expensive than equipment required for testing infants but assessing preschool children is tricky and requires investment in both time and human resources to get the right people for the job of working with such single-minded individuals. Pulmonary function testing in research: Infant and preschool lung function testing is being used in several research contexts. Recent studies that have used these tests have helped advance our knowledge on the early pathophysiology of diverse respiratory conditions such as cystic fibrosis, infant and preschool wheezing, childhood asthma, broncho-pulmonary dysplasia, as well as providing insights into aspects of lung growth and development. Pulmonary function testing in clinical practice: Infant and preschool lung function tests are also widely used (rightly or wrongly) for clinical evaluation. To be of benefit in clinical practice pulmonary function testing needs to be able to identify diminished lung function that may require a clinical response (this depends on good healthy control or reference data), to monitor disease status over time (depends on data on repeatability in both health and disease) and the response to therapeutic interventions (data on short-term repeatability required). Interpretation is currently limited in all these areas but general consensus is that the tests are on the cusp of being used routinely in clinical practice. Tests used in infants: The most popular tests in infants are those assessing forced expiratory flows and volumes (such as the raised volume and tidal rapid thoraco-abdominal compression techniques), plethysmography to measure functional residual capacity, and tests of ventilation inhomogeneity (such as the multiple breath inert gas washout). Limitations include the need for sedation, labour costs, lack of reference data and lack of longer-term repeatability data. Commercial equipment for each of these tests is, however, available. Tests used in preschool children: Popular tests in preschool children include those performed during tidal breathing such as the forced oscillation technique, resistance interrupter technique and multiple breath washout. Forced expiration using spirometry, with or without incentive, is also possible and widely used in preschool children. The technique of measuring the specific airways resistance is widely used in Europe and is in the process of undergoing standardization. Intervention studies and clinical trial networks: One outcome of lung function testing in infants and preschool children over the past few decades has been the insight gained into this crucial period of lung development where early insults to the developing lung architecture may have life-long effects in both chronic respiratory disorders and health. In the future, it is crucial that interventions are targeted early in life in order to prevent, rather than limit or reverse, the development of lung disease or maldevelopment of the lung. Infant and preschool lung function tests have been proposed as potential outcomes of such early intervention studies and have been used recently in this context. Multi-centre clinical trial networks are being developed for such studies that necessitate ongoing efforts to standardise the tests, develop quality assurance programs and facilitate better interchange of data between centres. Summary: Disappointingly, some of the limitations that have hindered interpretation of the results of infant (in particular), but also preschool, lung function tests over the past three decades are still to be overcome. However, advances in knowledge through research studies that have incorporated these tests, the commercial availability of several tests, the increasing number of centres gaining experience in their use and the recognition of the crucial role of
early lung development in life-long lung health have served to highlight the importance of overcoming the limitations so that infant and preschool lung function tests can be used routinely in clinical practice. New and hot topics in respiratory care PRL-13 Aerosol therapy: new drugs and new devices S. Devadason. School of Paediatrics and Child Health, University of Western Australia, Perth, Australia Currently, treatment for the majority of children affected by asthma in most countries may be primarily, or even solely, delivered using inhalation therapy. Efficacy of treatment can vary greatly, depending on the choice of inhaler device. Major advances have been made in the development of new inhalers over the last decade, and the potential efficiency of aerosol therapy for both adults and children has improved greatly. Inhaler devices are currently available which would maximise the amount of drug delivered to the lungs, while decreasing both oropharyngeal deposition and the amount of residual drug remaining within the device itself. Traditional inhaler devices currently used for asthma therapy are a. pressurised metered dose inhalers (pMDIs), used with or without holding chambers, b. dry powder inhalers (DPIs) and c. nebulisers, both jet nebulisers with compressors and the more compact vibrating mesh nebulisers Even when these devices are used optimally, only 10–50% of the drug dose will deposit in an adult patient’s lungs. For infants and young children, the amount of drug reaching the lungs is generally well under 10% [1,2], and can be less than 2% [3]. Devices with the potential for more efficient drug delivery, such as the vibrating mesh nebulisers (e.g. eFlow Rapid; Aeroneb Go), may need to be ‘dumbed down’ so that their drug output matches the devices currently on the market, for current asthma medications. However with the development of newer, and potentially much more costly, therapeutic options in the future, highly efficient aerosol delivery systems will be required to deliver strictly quantified doses to targeted lung regions. The increased cost of these newer devices may be offset by reduced wastage of expensive medications and improved therapeutic indices. Combining the improved efficiency of devices such as vibrating mesh nebulisers with drug delivery only during the optimal part of the inspiratory phase during tidal breathing, further reduces drug wastage and improves drug deposition in the lungs. Two examples of these are a. the adaptive aerosol delivery (AAD) technology used in the i-Neb, which adapts to the patient’s breathing and ensures accurate drug delivery [4] and b. the controlled breathing system used by the Akita2, which improves airway targeting [5] While costly, these devices can also be used to monitor patient adherence and inhalation technique, and to determine whether the complete drug dose has been delivered. References [1] Schuepp KG, Devadson S, Roller C, and Wildhaber JH. 2004. A complementary combination of delivery device and drug formulation for inhalation therapy in preschool children. Swiss Med Wkly. 134: 198– 200. [2] Everard ML. 1996. Aerosol delivery in infants and young children. J Aerosol Med. 9: 71–77. [3] Tal A, Golan H, Grauer N, Aviram M, Albin D, Quastel MR. 1996. Deposition pattern of radiolabeled salbutamol inhaled from a metereddose inhaler by means of a spacer with mask in young children with airway obstruction. J Pediatr. 128(4):479–84. [4] Geller DE and Kesser KC. 2010. The I-neb Adaptive Aerosol Delivery System enhances delivery of alpha1-antitrypsin with controlled inhalation. J Aerosol Med Pulm Drug Deliv. 23 Suppl 1: S55–59.
Oral Presentations / Paediatric Respiratory Reviews 13S1 (2012) S1–S50
PRL-11 Advances in infant and preschool lung function testing S. Ranganathan. Melbourne, Australia Background: Infant lung function tests are currently performed in more than 100 centres worldwide. Increasingly, centres in the AsiaPacific region are purchasing expensive and specialized equipment for this purpose. Equipment for testing preschool equipment is generally less expensive than equipment required for testing infants but assessing preschool children is tricky and requires investment in both time and human resources to get the right people for the job of working with such single-minded individuals. Pulmonary function testing in research: Infant and preschool lung function testing is being used in several research contexts. Recent studies that have used these tests have helped advance our knowledge on the early pathophysiology of diverse respiratory conditions such as cystic fibrosis, infant and preschool wheezing, childhood asthma, broncho-pulmonary dysplasia, as well as providing insights into aspects of lung growth and development. Pulmonary function testing in clinical practice: Infant and preschool lung function tests are also widely used (rightly or wrongly) for clinical evaluation. To be of benefit in clinical practice pulmonary function testing needs to be able to identify diminished lung function that may require a clinical response (this depends on good healthy control or reference data), to monitor disease status over time (depends on data on repeatability in both health and disease) and the response to therapeutic interventions (data on short-term repeatability required). Interpretation is currently limited in all these areas but general consensus is that the tests are on the cusp of being used routinely in clinical practice. Tests used in infants: The most popular tests in infants are those assessing forced expiratory flows and volumes (such as the raised volume and tidal rapid thoraco-abdominal compression techniques), plethysmography to measure functional residual capacity, and tests of ventilation inhomogeneity (such as the multiple breath inert gas washout). Limitations include the need for sedation, labour costs, lack of reference data and lack of longer-term repeatability data. Commercial equipment for each of these tests is, however, available. Tests used in preschool children: Popular tests in preschool children include those performed during tidal breathing such as the forced oscillation technique, resistance interrupter technique and multiple breath washout. Forced expiration using spirometry, with or without incentive, is also possible and widely used in preschool children. The technique of measuring the specific airways resistance is widely used in Europe and is in the process of undergoing standardization. Intervention studies and clinical trial networks: One outcome of lung function testing in infants and preschool children over the past few decades has been the insight gained into this crucial period of lung development where early insults to the developing lung architecture may have life-long effects in both chronic respiratory disorders and health. In the future, it is crucial that interventions are targeted early in life in order to prevent, rather than limit or reverse, the development of lung disease or maldevelopment of the lung. Infant and preschool lung function tests have been proposed as potential outcomes of such early intervention studies and have been used recently in this context. Multi-centre clinical trial networks are being developed for such studies that necessitate ongoing efforts to standardise the tests, develop quality assurance programs and facilitate better interchange of data between centres. Summary: Disappointingly, some of the limitations that have hindered interpretation of the results of infant (in particular), but also preschool, lung function tests over the past three decades are still to be overcome. However, advances in knowledge through research studies that have incorporated these tests, the commercial availability of several tests, the increasing number of centres gaining experience in their use and the recognition of the crucial role of
early lung development in life-long lung health have served to highlight the importance of overcoming the limitations so that infant and preschool lung function tests can be used routinely in clinical practice. New and hot topics in respiratory care PRL-13 Aerosol therapy: new drugs and new devices S. Devadason. School of Paediatrics and Child Health, University of Western Australia, Perth, Australia Currently, treatment for the majority of children affected by asthma in most countries may be primarily, or even solely, delivered using inhalation therapy. Efficacy of treatment can vary greatly, depending on the choice of inhaler device. Major advances have been made in the development of new inhalers over the last decade, and the potential efficiency of aerosol therapy for both adults and children has improved greatly. Inhaler devices are currently available which would maximise the amount of drug delivered to the lungs, while decreasing both oropharyngeal deposition and the amount of residual drug remaining within the device itself. Traditional inhaler devices currently used for asthma therapy are a. pressurised metered dose inhalers (pMDIs), used with or without holding chambers, b. dry powder inhalers (DPIs) and c. nebulisers, both jet nebulisers with compressors and the more compact vibrating mesh nebulisers Even when these devices are used optimally, only 10–50% of the drug dose will deposit in an adult patient’s lungs. For infants and young children, the amount of drug reaching the lungs is generally well under 10% [1,2], and can be less than 2% [3]. Devices with the potential for more efficient drug delivery, such as the vibrating mesh nebulisers (e.g. eFlow Rapid; Aeroneb Go), may need to be ‘dumbed down’ so that their drug output matches the devices currently on the market, for current asthma medications. However with the development of newer, and potentially much more costly, therapeutic options in the future, highly efficient aerosol delivery systems will be required to deliver strictly quantified doses to targeted lung regions. The increased cost of these newer devices may be offset by reduced wastage of expensive medications and improved therapeutic indices. Combining the improved efficiency of devices such as vibrating mesh nebulisers with drug delivery only during the optimal part of the inspiratory phase during tidal breathing, further reduces drug wastage and improves drug deposition in the lungs. Two examples of these are a. the adaptive aerosol delivery (AAD) technology used in the i-Neb, which adapts to the patient’s breathing and ensures accurate drug delivery [4] and b. the controlled breathing system used by the Akita2, which improves airway targeting [5] While costly, these devices can also be used to monitor patient adherence and inhalation technique, and to determine whether the complete drug dose has been delivered. References [1] Schuepp KG, Devadson S, Roller C, and Wildhaber JH. 2004. A complementary combination of delivery device and drug formulation for inhalation therapy in preschool children. Swiss Med Wkly. 134: 198– 200. [2] Everard ML. 1996. Aerosol delivery in infants and young children. J Aerosol Med. 9: 71–77. [3] Tal A, Golan H, Grauer N, Aviram M, Albin D, Quastel MR. 1996. Deposition pattern of radiolabeled salbutamol inhaled from a metereddose inhaler by means of a spacer with mask in young children with airway obstruction. J Pediatr. 128(4):479–84. [4] Geller DE and Kesser KC. 2010. The I-neb Adaptive Aerosol Delivery System enhances delivery of alpha1-antitrypsin with controlled inhalation. J Aerosol Med Pulm Drug Deliv. 23 Suppl 1: S55–59.