In eight conscious spontaneously breathing adults we studied the decay of pressure developed by the inspiratory muscles during expiration (PmusI). PmusI was obtained according to the following equation: PmusI(t) = Ers X V(t) - Rrs X V(t), where V is volume and V is flow at any instant t during spontaneous expiration, and Ers and Rrs are, respectively, the passive elastance and resistance of the total respiratory system. Ers was determined with the relaxation method, and resistance with the interrupter method. All subjects showed marked braking of expiratory flow by PmusI. The mean time for PmusI to reduce to 50 and 0% amounted, respectively, to 23 and 79% of expiratory time. During expiration, 24-55% of the elastic energy stored during inspiration was used as resistive work and the remainder (45-76%) as negative work.

Non-invasive ventilation (NIV) is increasingly being used in hospitals to treat respiratory failure. The use of NIV with palliative intent in a district general hospital is described and ten illustrative cases where NIV was used in an attempt to palliate symptoms or to 'buy time' are presented. The role of NIV in relieving symptoms in various conditions is reviewed and ethical aspects are considered. It is suggested that hospital palliative care teams will increasingly see patients treated by this technique as it becomes more widely used for exacerbations of chronic obstructive airways disease, for relief of breathlessness in the terminally ill and for buying time in patient management. Domiciliary teams will see increasing numbers of people with motor neurone disease and other conditions treated with NIV.

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A 3-year study assessed the diagnostic accuracy of touch imprint smears in the diagnosis of lung cancer. Touch imprint smears were prepared from 90 computerized tomographic-guided core needle lung biopsies. Cytological diagnosis of touch imprint smears were correlated with the histological diagnosis of the corresponding core needle biopsy specimen, which was taken as the gold standard. The sensitivity, specificity, positive predictive value and negative predictive value of imprint smear results were 89%, 100%, 100% and 68%, respectively. There were no false positives, and all patients with small cell lung cancer were correctly diagnosed with this technique. Imprint cytology can be used to provide a rapid, preliminary diagnosis of lung cancer.

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