Determinants Of Circulating Surfactant Protein Levels In Health And Disease
Funder
National Health and Medical Research Council
Funding Amount
$276,221.00
Summary
The lung allows the oxygenation of blood and clearance of carbon dioxide. To achieve this a large surface area (50-100 m2) interfaces with a complex microcirculation across a 0.1-0.2 ?m barrier - the alveolocapillary membrane. The alveolocapillary membrane is damaged under a variety of circumstances, of varying severity. Whereas severe impairment results in respiratory failure, often there is no clear delineation between OacceptableO and OpathologicalO changes. Therefore, we have coined the term ....The lung allows the oxygenation of blood and clearance of carbon dioxide. To achieve this a large surface area (50-100 m2) interfaces with a complex microcirculation across a 0.1-0.2 ?m barrier - the alveolocapillary membrane. The alveolocapillary membrane is damaged under a variety of circumstances, of varying severity. Whereas severe impairment results in respiratory failure, often there is no clear delineation between OacceptableO and OpathologicalO changes. Therefore, we have coined the term Olung healthO to encompass the broad spectrum. Generally speaking, lung health can be compromised by lifestyle or disease. Whereas lifestyle changes are typically progressive and chronic, those associated with disease tend to be severe and acute. Monitoring lung health clearly has important implications in terms of occupational health and lifestyle issues, including smoking. The need for a marker of lung permeability is also regarded as the Oholy grailO in the intensive care setting. Currently, there is no way of doing so. The alveolus is lined with a liquid layer into which is secreted a complex mixture of lipids and specific proteins known as alveolar surfactant. Surfactant reduces the work of breathing. Recently, we fortuitously discovered that surfactant proteins leak into the circulation and that changes in their levels are a sensitive and early generic index of the lung?s integrity. We discovered that lung damage from conditions as diverse as smoking to the acute respiratory distress syndrome elevate circulating surfactant proteins levels. To refine our discovery we aim to: Improve the techniques used to measure the proteins Study the rate at which they enter and clear the circulation Study the influence of storage, gender, age, circadian rhythm, and smoking on the levels Study the levels in acute lung injury and in radiotherapy and cytotoxic drug treatment where the ability to monitor lung damage has immediate benefit for the patients.Read moreRead less
Randomised Controlled Trial Of Therapeutic Pulmonary Lavage In Meconium Aspiration Syndrome
Funder
National Health and Medical Research Council
Funding Amount
$182,550.00
Summary
Meconium aspiration syndrome (MAS) is a serious respiratory disease of full term infants, which can lead to very severe respiratory failure. It is caused by the inhalation of meconium, the secretion of the fetal intestine, into the lung at or prior to delivery. As a result, the airways and air sacs within the lung are damaged, leading to difficulty with breathing and poor oxygen levels. About one-third of all infants with MAS require mechanical ventilation in the first days of life, and are ofte ....Meconium aspiration syndrome (MAS) is a serious respiratory disease of full term infants, which can lead to very severe respiratory failure. It is caused by the inhalation of meconium, the secretion of the fetal intestine, into the lung at or prior to delivery. As a result, the airways and air sacs within the lung are damaged, leading to difficulty with breathing and poor oxygen levels. About one-third of all infants with MAS require mechanical ventilation in the first days of life, and are often extremely difficult to manage. At present, the main treatments given to a ventilated infant with severe MAS are supportive, rather than curative. Lung cleansing procedures are not part of routine care in this condition, even though removal of meconium from the lung may reduce the amount of damage that occurs. This project is a randomised controlled trial of a lung cleansing procedure called lung lavage in ventilated infants with severe MAS. During the lung lavage, a quantity of cleansing fluid containing a natural substance called surfactant is introduced into the lung, and then removed by suctioning. This procedure cleanses the lung of some of the meconium, and in preliminary testing, appears to be safe and well-tolerated even in the sickest infants. In the proposed trial, we will randomly allocate ventilated infants with severe MAS to receive either a lung lavage procedure, or routine care. This will take place within 24 hours of birth. We are looking to see whether the lavage procedure shortens the duration of ventilation, oxygen therapy or hospitalisation. Because there are only a small number of ventilated infants with MAS at any one centre per year, we will involve as many Australian neonatal intensive care units as we can in the study. We aim to enrol 66 infants in the trial, of whom half will receive lavage therapy.Read moreRead less