Brendan Cooper

Improved Criterion for Assessing Lung Function Reversibility

BACKGROUNDnConsensus on how best to express bronchodilator reversibility (BDR) is lacking. We tested different BDR criteria against the null hypotheses that BDR should show no sex or size bias. To determine the best criterion for defining BDR, we hypothesized that clinically important BDR should be associated with better survival in respiratory patients compared with that of patients without BDR.nnnMETHODSnWe used the first BDR test of 4,231 patients who had known subsequent survival status (50.8% male sex; mean age, 60.9 years; mean survival, 5.2 years [range, 0.1-16.5 years]). BDR for FEV1 was expressed as absolute change, % baseline change, and change as % predicted FEV1.nnnRESULTSnHaving BDR defined from absolute change was biased toward men (male to female ratio, 2.70) and toward those with larger baseline FEV1. BDR defined by % change from baseline was biased toward those with lower baseline values. BDR defined by % predicted had no sex or size bias. Multivariate Cox regression found those with FEV1 BDR > 8% predicted (33% of the subjects) had an optimal survival advantage (hazard ratio, 0.56; 95% CI, 0.45-0.69) compared with those with FEV1 BDR ≤ 8% predicted. The survival of those with FEV1 BDR > 8% predicted was not significantly different from that of those with FEV1 BDR > 14% predicted but was significantly better than that of those with FEV1 BDR < 0.nnnCONCLUSIONSnWe have shown that expressing FEV1 BDR as % predicted avoids sex and size bias. FEV1 BDR > 8% predicted showed optimal survival advantage and may be the most appropriate criterion to define clinically important reversibility.

Home oxygen and domestic fires

Educational aims To highlight the risk of domestic fires in the home use of oxygen To recommend measures to reduce the risk

Applied Lung Physiology

This chapter has been written by two clinicians with immense experience in the measurement and interpretation of lung function testing; one a physician and one a physiologist, but both extremely passionate about educating others in understanding lung function. As an introduction to lung function testing for the trainee respiratory physician, this chapter covers some of the essential questions including “Why test lung function?”, “What’s normal and abnormal lung function?”, and “What are the basic principles of the main lung function tests?”

Determining the optimal approach to identifying individuals with chronic obstructive pulmonary disease: The DOC study

RATIONALE, AIMS, AND OBJECTIVESnEarly identification of chronic obstructive pulmonary disease (COPD) results in patients receiving appropriate management for their condition at an earlier stage in their disease. The determining the optimal approach to identifying individuals with chronic obstructive pulmonary disease (DOC) study was a case-finding study to enhance early identification of COPD in primary care, which evaluated the diagnostic accuracy of a series of simple lung function tests and symptom-based case-finding questionnaires.nnnMETHODSnCurrent smokers aged 35 or more were invited to undertake a series of case-finding tools, which comprised lung function tests (specifically, spirometry, microspirometry, peak flow meter, and WheezoMeter) and several case-finding questionnaires. The effectiveness of these tests, individually or in combination, to identify small airways obstruction was evaluated against the gold standard of spirometry, with the quality of spirometry tests assessed by independent overreaders. The study was conducted with general practices in the Yorkshire and Humberside area, in the UK.nnnRESULTSnSix hundred eighty-one individuals met the inclusion criteria, with 444 participants completing their study appointments. A total of 216 (49%) with good-quality spirometry readings were included in the analysis. The most effective case-finding tools were found to be the peak flow meter alone, the peak flow meter plus WheezoMeter, and microspirometry alone. In addition to the main analysis, where the severity of airflow obstruction was based on fixed ratios and percent of predicted values, sensitivity analyses were conducted by using lower limit of normal values.nnnCONCLUSIONSnThis research informs the choice of test for COPD identification; case-finding by use of the peak flow meter or microspirometer could be used routinely in primary care for suspected COPD patients. Only those testing positive to these tests would move on to full spirometry, thereby reducing unnecessary spirometric testing.

P37 Preliminary normal values for structured light plethysmography tidal breathing parameters and age and gender differences

Introduction This is the first report from an ongoing study to define normal values for Structured Light Plethysmography (SLP) tidal breathing parameters in adults. Structured Light Plethysmography (SLP) is a non-contact, non-invasive respiratory measurement technology that utilises the movement of thoraco-abdominal (TA) wall to measure a range of tidal breathing parameters. Various studies have been using SLP but lack of normative values can make any clinical judgement difficult. Methods :As a part of an on-going collaboration between PneumaCare Ltd. and Queen Elizabeth (QE) Hospital (Birmingham, UK), 107 healthy adult subjects between ages of 18 to 69 were measured with SLP during 4 to 5 minutes of seated tidal breathing. Parameter means and standard deviations for males and females aged 18–39 and 40–69 were calculated and gender and age related comparisons were made (t-test). Results Tables 1 summarises the normative values for males and females older and younger than 40 years. Three parameters showed age related differences and one parameter showed a gender related difference. Conclusion Preliminary normal values for SLP derived tidal breathing parameters are reported. Some gender and age related differences are apparent. It is interesting that tPTEF/tE was significantly lower in the older participants, possibly a sign of natural airway obstruction associated with age. Abstract P37 Table 1 SLP Tidal Breathing Parameters for adult male and female normals aged 18–69 years Parameter Males 18–39 yrs (n = 32) Mean±SD Males 40–69 yrs (n = 25) Mean ± SD Young vs older males, t (p) Females 18–39 (n = 21) Mean ± SD Females 40–69 yrs (n = 29) Mean ± SD Young vs older Females, t (p) Males vs. Females (all ages), t (p) TAA 5.7 ± 23.3 4.75 ± 2.69 1.18 (0.24) 4.85 ± 2.45 4.8 ± 1.83 0.08 (0.94) 0.92 (0.36) LRHTA 2.24 ± 2.13 2.39 ± 1.64 −0.298 (0.77) 1.58 ± 0.69 2.04 ± 1.43 −1.36 (0.18) 1.47 (0.14) %RC 45.87 ± 13.07 56.29 ± 11.03 −3.2(<0.01) 60.23 ± 8.55 61.31 ± 10.33 −0.39 (0.70) −4.62(<0.001) IE50 1.34 ± 0.27 1.25 ± 0.18 1.48 (0.14) 1.37 ± 0.2 1.42 ± 0.29 −0.64 (0.52) −1.94 (0.06) tPTEF/tE 0.34 ± 0.09 0.26 ± 0.07 3.67(<0.001) 0.32 ± 0.09 0.26 ± 0.06 2.62(<0.05) 0.91 (0.36) tPTIF/tI 0.49 ± 0.09 0.55 ± 0.09 −2.69(<0.01) 0.5 ± 0.08 0.52 ± 0.07 0.88 (0.38) −1.13 (0.26) TAA: Thoraco-abdominal asynchrony (TAA), LRHTA:left vs Right Hemi-thoracic asynchrony, IE50:Inspiratory to expiratory flow at 50% of tidal volume calculated from thoraco-abdominal wall displacement, tPTEF/tE: normalised time to reach peak tidal expiratory flow, tPTIF/tI: normalised time to reach peak tidal inspiratory flow