Dipansu Ghosh

Validation of the English Severe Respiratory Insufficiency Questionnaire

Assessment of health-related quality of life in patients with respiratory failure on home ventilation requires appropriate and highly specific measurement tools. We attempt to validate the English version of the Severe Respiratory Insufficiency Questionnaire (SRI). Psychometric properties of the SRI in 152 patients established on home ventilation were assessed. Cronbach’s alpha ranged between 0.77 and 0.89 for the seven subscales and and was 0.93 for the summary scale. Principal components analysis revealed a one-factor solution for four and two factors for three subscales. Confirmatory factor analysis revealed a two-factor solution for six subscales, but these factors were dependent on each other. One factor was extracted out of the subscales confirming one summary scale accounting for 70% of the total variance. Correlation analysis between scales of the SRI and the Medical Outcome Study 36-item short-form health survey demonstrated highest correlations between comparable subscales. Chronic obstructive pulmonary disease patients had lower summary scale scores than patients with restrictive chest wall diseases, neuromuscular disorders and obesity hypoventilation syndrome. The English SRI has high internal consistency reliability, clearly established construct and concurrent validity, and is capable of differentiating between different diseases. It is now validated for use in research involving patients receiving home ventilation.

Continuous measures of driving performance on an advanced office-based driving simulator can be used to predict simulator task failure in patients with obstructive sleep apnoea syndrome

Introduction Some patients with obstructive sleep apnoea syndrome are at higher risk of being involved in road traffic accidents. It has not been possible to identify this group from clinical and polysomnographic information or using simple simulators. We explore the possibility of identifying this group from variables generated in an advanced PC-based driving simulator. Methods All patients performed a 90 km motorway driving simulation. Two events were programmed to trigger evasive actions, one subtle and an alert driver should not crash, while for the other, even a fully alert driver might crash. Simulator parameters including standard deviation of lane position (SDLP) and reaction times at the veer event (VeerRT) were recorded. There were three possible outcomes: ‘fail’, ‘indeterminate’ and ‘pass’. An exploratory study identified the simulator parameters predicting a ‘fail’ by regression analysis and this was then validated prospectively. Results 72 patients were included in the exploratory phase and 133 patients in the validation phase. 65 (32%) patients completed the run without any incidents, 45 (22%) failed, 95 (46%) were indeterminate. Prediction models using SDLP and VeerRT could predict ‘fails’ with a sensitivity of 82% and specificity of 96%. The models were subsequently confirmed in the validation phase. Conclusions Using continuously measured variables it has been possible to identify, with a high degree of accuracy, a subset of patients with obstructive sleep apnoea syndrome who fail a simulated driving test. This has the potential to identify at-risk drivers and improve the reliability of a clinicians decision-making.

Variability in clinicians' opinions regarding fitness to drive in patients with obstructive sleep apnoea syndrome (OSAS).

We evaluated clinicians’ current practice for giving advice to patients with obstructive sleep apnoea syndrome. Clinicians were invited to complete a web-based survey and indicate the advice they would give to patients in a number of scenarios about driving; they were also asked what they considered to be residual drowsiness and adequate compliance following CPAP treatment. In the least contentious scenario, 94% of clinicians would allow driving; in the most contentious a patient had a 50% chance of being allowed to drive. Following treatment with CPAP, clinicians’ interpretation of what constituted residual drowsiness was inconsistent. In each vignette the same clinician was more likely to say ‘yes’ to ‘excessive’ than to ‘irresistible’ (71%±12% vs 42%±10%, p=0.0045). There was also a lack of consensus regarding ‘adequate CPAP compliance’; ‘yes’ responses ranged from 13% to 64%. There is a need for clearer guidance; a recent update to the Driver and Vehicle Licensing Agency guidance, and a statement from the British Thoracic Society, making it clear that sleepiness while driving is the key issue, may help.

Factors that affect simulated driving in patients with obstructive sleep apnoea

Patients with obstructive sleep apnoea syndrome (OSAS) are at increased risk of involvement in road traffic accidents (RTAs) [1]. Clinicians diagnosing OSAS need to advise patients about driving but there are no validated tools and no robust objective data about which factors are important [2]. There are position statements, based solely on expert opinion, from various professional bodies [3–6]. In general, they conclude that a patient with significant daytime sleepiness and a recent RTA or near miss attributable to sleepiness, fatigue or inattention, should be considered a high-risk driver [3–6]. In a recent survey using clinical vignettes, we have shown that there is considerable variability in the advice that patients are likely to receive [7]. This indicates that clinicians require more robust guidance. Objective data for advising sleep apnoea sufferers whether they are at increased risk of an accident when driving http://ow.ly/TWPgm

Respiratory Failure and Non-invasive Ventilation

Respiratory failure results from a failure of pulmonary gas exchange caused by many processes that affect the delivery of oxygen to alveoli and pulmonary circulation, and in some cases, the clearance of carbon dioxide. The spectrum of pathophysiological mechanisms is described in this chapter. The use of non-invasive ventilation (NIV) in acute exacerbations of chronic obstructive pulmonary disease (COPD) is now established practice, but its use in type 1 respiratory failure caused by pneumonia, accute respiratory distress syndrome (ARDS), pulmonary fibrosis, and cardiogenic pulmonary oedema is less well defined. Domiciliary NIV is effective in patients with obesity, chest wall deformity, and slowly progressive neuromuscular disease, and use has recently been extended to more rapidly progressive neurological disease such as Duchenne muscular dystrophy and motor neurone disease. Potentially the largest group with type 2 respiratory failure is severe COPD, but until recently the benefits of home mechanical ventilation have been unproven. Recent work suggests more aggressive ventilatory strategies in carefully selected subgroups may impact on readmission and mortality.

The impact of three discharge coding methods on the accuracy of diagnostic coding and hospital reimbursement for inpatient medical care

BACKGROUND Coding of diagnoses is important for patient care, hospital management and research. However coding accuracy is often poor and may reflect methods of coding. This study investigates the impact of three alternative coding methods on the inaccuracy of diagnosis codes and hospital reimbursement. METHODS Comparisons of coding inaccuracy were made between a list of coded diagnoses obtained by a coder using (i)the discharge summary alone, (ii)case notes and discharge summary, and (iii)discharge summary with the addition of medical input. For each method, inaccuracy was determined for the primary, secondary diagnoses, Healthcare Resource Group (HRG) and estimated hospital reimbursement. These data were then compared with a gold standard derived by a consultant and coder. RESULTS 107 consecutive patient discharges were analysed. Inaccuracy of diagnosis codes was highest when a coder used the discharge summary alone, and decreased significantly when the coder used the case notes (70% vs 58% respectively, p < 0.0001) or coded from the discharge summary with medical support (70% vs 60% respectively, p < 0.0001). When compared with the gold standard, the percentage of incorrect HRGs was 42% for discharge summary alone, 31% for coding with case notes, and 35% for coding with medical support. The three coding methods resulted in an annual estimated loss of hospital remuneration of between £1.8 M and £16.5 M. CONCLUSION The accuracy of diagnosis codes and percentage of correct HRGs improved when coders used either case notes or medical support in addition to the discharge summary. Further emphasis needs to be placed on improving the standard of information recorded in discharge summaries.

Looking under the bonnet of patient–ventilator asynchrony during noninvasive ventilation: does it add value?

Noninvasive ventilation (NIV) has significant advantages over invasive ventilation in certain situations, such as hypercapnic respiratory failure due to an acute exacerbation of chronic obstructive pulmonary disease (COPD), acute cardiogenic pulmonary oedema, respiratory failure in immunocompromised patients and weaning from invasive ventilation in patients with COPD, in terms of reducing mortality, duration of hospital stay, the need for intubation and infectious complications [1–5]. During noninvasive ventilation it is reasonable to try to abolish clinically apparent patient-ventilator asynchronies but the use of more invasive tests to detect subtle asynchronies cannot be justified http://ow.ly/rXoA30gCm8O

P65 OSAS and driving – BTS return survey to assess consistency of advice given to patients at diagnosis and after treatment– a repeat of the 2013 survey to evaluate the impact of a BTS statement and new DVLA regulations

Introduction In 2013 a BTS survey showed substantial variability in the advice that patients with obstructive sleep apnoea syndrome (OSAS) would be likely to receive from clinicians with regard to whether they were fit to drive or not. Since then the BTS has issued guidance and the DVLA changed its emphasis to sleepiness “likely to impair safe driving”, rather than sleepiness in general. The survey was divided into two parts, the first focusing on patients at presentation and the second after treatment, with the wording of the questions reflecting that used in the DVLA forms. We repeated this study in 2016 to assess whether these changes had resulted in greater consistency. Additional questions about BTS and DVLA guidance were included. Methods Web based survey of members of BTS, BSS and ARTP. Results 304 respondents. The vignettes at diagnosis are directly comparable between the surveys and the results are very similar (p = NS). In the most contentious case there remains an approximately 50:50 chance of a patient receiving opposing advice. Significant variation in the assessments of control of patient’s condition, improvement in sleepiness and compliance after treatment remains (Figure 1). 2 36% were not aware that the BTS have issued a statement 63% felt the change in emphasis from excessive sleepiness to sleepiness likely to impair safe driving helpful. 64% of respondents were not aware that DVLA had changed its guidance in January 2016. 18% of respondents advise patients to inform the DVLA when diagnosis felt to be likely based on symptoms. 57% when diagnosis confirmed following investigation, 13% when CPAP first trialled and 12% when CPAP issued to the patient. Conclusions The results of the 2016 survey confirm the results of the 2013 survey. Disappointingly the guidance from the BTS appears to have had little impact. The change in emphasis from excessively sleepy to sleepiness likely to impair safe driving was felt to be helpful by a small majority. There is a clear need for tools which are felt to be robust by clinicians and patients to help make decisions about fitness to drive and for these to be disseminated to clinicians. Abstract P65 Figure 1

Noninvasive ventilation in hypoxemic respiratory failure

Noninvasive ventilation (NIV) refers to positive pressure ventilation delivered through a noninvasive interface (nasal mask, facemask, or nasal plugs) etc. Over the past decade its use has become more common as its benefits are increasingly recognized. This review will focus on the evidence supporting the use of NIV in various conditions resulting in acute hypoxemic respiratory failure (AHRF), that is, non-hypercapnic patients having acute respiratory failure in the absence of a cardiac origin or underlying chronic pulmonary disease. Outcomes depend on the patients diagnosis and clinical characteristics. Patients should be monitored closely for signs of noninvasive ventilation failure and promptly intubated before a crisis develops. The application of noninvasive ventilation by a trained and experienced team, with careful patient selection, should optimize patient outcomes.

European Union directive 2014/85/EU on driver licensing in obstructive sleep apnoea: early experiences with its application in the UK

Obstructive sleep apnoea (OSA) is a prevalent condition, affecting up to 20% of the population in first world countries [1]. The obstructive sleep apnoea hypopnea syndrome (OSAHS) is diagnosed when symptoms of excessive daytime somnolence or cognitive impairment are present in the context of an elevated apnoea-hypopnoea index (AHI) per hour of sleep. The definitions vary according to the lower cut-off for the AHI, which can range from >5 to >15 events per hour [2]. However, as with any sleep disorder, it is important to establish whether the sleep disordered breathing (SDB) per se is the true cause of symptoms of daytime somnolence. As is apparent to everyone who practises in the area, a large number of other factors can intervene, such as shift work, sleep insufficiency, psychiatric disorders, metabolic disorders and nutritional deficiencies, which may be the true cause of the somnolence rather than the AHI as measured on polysomnography. Additionally, a true AHI cannot be reported on the basis of any respiratory measurements conducted during sleep, if no electroencephalogram is simultaneously recorded [2]. OSA patients’ risk of RTA should be assessed using detailed driving history with specific focus on “red flags” http://ow.ly/mxPi305isni