Device to measure lung function in children and adults

Patients suffering from lung diseases require lung function tests to assess the severity of their disease and to monitor the benefit of any therapy. These tests are commonly performed in specialised hospital laboratories, and require the co-operation of the patient and a rapport between the clinician and patient.

Adults and babies in Intensive Care Units (ICUs) are dependent on continuous life support, and so cannot be moved to these specialised laboratories. Unfortunately therefore, those patients who would benefit most from heart-lung function tests, are the most difficult to be assessed by conventional means. This is also true for anaesthetised patients in the operating theatre, since the unconscious patient is unable to participate in volitional respiratory manoeuvres.

Severely premature babies have immature lungs and mostly require ventilation. At present, there is no clear way to determine how much inflating pressure to apply to the lungs. Too little pressure results in under-aeration, and too much causes lung trauma. There is a need to continually monitor the degree of lung inflation. A great need therefore exists for a new system to measure lung functions non-invasively.

The purpose of our research is to develop such a new medical device, made possible by recent advancements in gas sensors and flow control technologies. By using small perturbations in oxygen and nitrous oxide in the inhaled breath, and measuring the responses in real time, we can measure heart-lung function indirectly. An online computer model of the lung is used to convert sensor data to robust estimations of lung volume, ventilation, lung blood flow, and especially lung inhomogeneity. This approach eliminates the need for patients' cooperation, and also does not interfere with his/her breathing pattern.

As no similar technology currently exists, our proposed technique and device will have a large impact on UK and global health care, especially in outpatient clinics, the ICU environment, and in the operating theatre.

This new technique could significantly aid the clinicians in selecting the ventilator settings, and adjusting other therapeutic measures, to (a) "titrate" the therapy to "best effect" in any individual patient; and (b) help avoid the ever present problem of ventilator-induced lung injury worldwide. This is especially true in the early management of preterm infants who have fragile and rapidly changing lung and are at greater risk from over distension and subsequent injury.

IMPROVING HEATH AND WELL-BEING OF INTENSIVE CARE UNIT PATIENTS
The commonest reason for admission to ICUs is the need of mechanical ventilatory support, due either to primary ventilatory failure, or acute lung injury in parallel with other organ failures. Moreover, mechanical ventilation itself can further injure the already sick lung, leading to ventilator-induced lung injury (VILI).

Existing techniques for monitoring the degree of lung dysfunction require patients' cooperation. Unlike ambulatory patients, ICU patients cannot cooperate with conventional lung function tests. It is therefore, unfortunate that those patients who would benefit most from lung function tests, are the most difficult to be assessed.

Our research aims to develop a new device to measure lung and cardiopulmonary function noninvasively, without the need for patients' cooperation, and without interfering with the patients' ventilation setup.

This new technique could significantly aid the clinician in optimizing the ventilator settings, and adjusting other therapeutic measures such as PEEP, to titrate the therapy to best effect in any individual patient, and minimize the incidence of VILI worldwide.

IMPROVING HEATH AND WELL-BEING OF PEDIATRIC AND NEONATAL PATIENTS
All the above problems are greatly magnified in the preterm infants and the small children. Despite technological advancements, the rates of chronic lung disease remain largely unchanged in extreme preterm infants who have fragile lungs which are vulnerable to VILI.

Our new device, providing noninvasive, continuous measurements by the bedside, could be exploited to optimise ventilatory manipulations. This is especially true in the early management of preterm infants who have rapidly changing lung compliance and are at risk from over distension and subsequent injury.

Likewise, the direct knowledge of blood flow and volume in the lungs of infants, who become critically unwell due to overwhelming infection or pulmonary hypertension, could be used dynamically to adjust ventilatory parameters and inform drug choices for manipulation of pulmonary blood flow.

ENHANCING THE EFFECTIVENESS OF THE MEDICAL COMMUNITY, TO DIAGNOSE AND TREAT LUNG DISEASES
Chronic Obstructive Pulmonary Disease (COPD) currently affects 210 million people globally and causes 3 million deaths per year. This is the tip of the iceberg, since COPD still only represents 25% of the global burden caused by chronic respiratory disease . For children, Chronic respiratory disease is less common, but Cystic Fibrosis (CF) comprises a significant caseload in the 24 UK specialist CF centres. Lung diseases are often diagnosed late and treated suboptimally by which time irreversible structural changes within the airways and parenchyma have occurred.

Current lung function testing technologies are relatively insensitive in detecting early changes, and dependent on patient cooperation and effort. They also require to be undertaken by trained staff to ensure adequate patient effort and high quality information. A shortfall of appropriately trained staff is one of the factors impairing the delivery of the current UK National Strategy to improve care in COPD.

Our new device would be easier to administer and yields automatic outputs, substantially simplifying test interpretation. This is likely to be a very cost-effective way of coping with the current difficulties with diagnosis and assessment, while minimizing the need for a large expansion of expensive trained staff.

ECONOMIC BENEFIT
No competing technology currently exists to measure simultaneously, noninvasively and online lung function and pulmonary blood flow without the patient's cooperation. Our new technology will therefore meet a worldwide unmet healthcare need, and should be attractive to UK healthcare companies.

If successfully make to the market, the technology will contribute to UK's status as one of the leaders in healthcare industry.