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Computer aided rehabilitation of respiratory disabilities

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Helium and oxygen mix for easy breathing

Chronic airflow limitation can cause a serious loss of quality of life for sufferers. Therapeutic exercise regimes involving the manipulation of inhaled gas ratios have been devised by research scientists as part of the drive to alleviate this situation.


Chronic obstructive pulmonary disease (COPD) is a major public health concern in both Europe and the United States. At the time of this research, the World Health Organisation estimated it to be the sixth most common cause of death worldwide. From the point of view of quality of life, it has a devastating effect on employment prospects for the patient. This is mainly due to the inability to exercise. To address this problem, CARED project partners at the University Hospital in Aintree, Liverpool aimed to evaluate how management of the gas ratios in inspired air may improve the ability to exercise. The rationale behind the trials involving 82 patients with stable COPD was that increasing oxygen (O2) levels can reduce breathlessness. Furthermore, replacing nitrogen (N2) with helium (He) was known to reduce expiratory flow resistance and therefore may improve lung emptying. In a randomised crossover trial, patients were given different gas mixtures of He, O2 and N2 using a face mask. Medical air with the usual ratio of 79% N2 and 21% O2 was applied as a control. Performance was measured by endurance shuttle walking distance and difficulty of breathing at the end of exercise (dyspnoea). The team found that Heliox28 (with 72% He and 28% O2) gave the best results. Walking distance was at an optimum and dyspnoea reduced as compared with medical air. Overall, the use of a much reduced density helium gas as compared with nitrogen improved exercise as much as increasing the O2 levels. These independent effects can be realised with the use of Heliox28 for maximised benefits in patients with severe airflow obstruction. Specially designed exercise regimes could mean return to employment for those previously disabled by COPD. The implementation of optimised exercise means economic treatment with better outcomes, shorter intensive care stay periods and a much improved quality of life for the patient.

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