Background -Inspiratory muscle strength is often better reflected by oesophageal pressure during a maximal sniff (sniff POES) than by maximal inspiratory pressure (PImax). Sniff POES can be estimated non-invasively by measuring the sniff nasal inspiratory pressure (SNIP). The aim was to establish maximal normal values for the SNIP and to compare them with PImax.Methods -One hundred and sixty healthy subjects (80 men) aged 20-80 years were recruited. All subjects had a forced vital capacity (FVC) of >80%, a forced expiratory volume in one second (FEV1)IFVC of >85% predicted value, and a body mass index of 18-31 kg/m2. Because Pimax is known to be reduced in the supine posture, the SNIP was measured in both the sitting and the supine positions. Pimax sustained over one second was measured from functional residual capacity (FRC) in the sitting position with a standard flanged mouthpiece during four manoeuvres. SNIP was measured from FRC in the sitting and supine positions using a catheter through a plug occluding one nostril during 10 maximal sniffs through the contralateral nostril. For each test the largest pressure measured in cm H2O was taken into account. Results -For both men and women maximal SNIP was negatively correlated with age, and was similar in the sitting and the supine positions. In the sitting position maximal SNIP was greater or equal to PImax in 107 of 160 subjects. The mean (SD) ratio SNIP/Pimax was 1l08 (0.22) in men and 1-17 (0.29) in women.Conclusions -Normal values of maximal SNIP can be predicted from age and sex. Maximal SNIP is similar in the sitting and the supine position and is significantly higher than Pimax in healthy subjects. The low level of agreement between maximal SNIP and Pimax indicates that the two manoeuvres are not interchangeable but complementary.

BACKGROUND: Noninvasive ventilation (NIV) is standard of care for chronic hypercapnic respiratory failure, but indications, devices, and ventilatory modes are in constant evolution.RESEARCH QUESTION: To describe changes in prevalence and indications for NIV over a 15-year period; to provide a comprehensive report of characteristics of the population treated (age, comorbidities, and anthropometric data), mode of implementation and follow-up, devices, modes and settings used, physiological data, compliance, and data from ventilator software. STUDY DESIGN AND METHODS:Cross-sectional observational study designed to include all subjects under NIV followed by all structures involved in NIV in the Cantons of Geneva and Vaud (1,288,378 inhabitants).RESULTS: A total of 489 patients under NIV were included. Prevalence increased 2.5-fold since 2000 reaching 38 per 100,000 inhabitants. Median age was 71 years, with 31% being > 75 years of age. Patients had been under NIV for a median of 39 months and had an average of 3 AE 1.8 comorbidities; 55% were obese. COPD (including overlap syndrome) was the most important patient group, followed by obesity hypoventilation syndrome (OHS) (26%). Daytime PaCO 2 was most often normalized. Adherence to treatment was satisfactory, with 8% only using their device < 3.5 h/d. Bilevel positive pressure ventilators in spontaneous/timed mode was the default mode (86%), with a low use of autotitrating modes. NIV was initiated electively in 50% of the population, in a hospital setting in 82%, and as outpatients in 15%.INTERPRETATION: Use of NIV is increasing rapidly in this area, and the population treated is aging, comorbid, and frequently obese. COPD is presently the leading indication followed by OHS.

Differences in PO 2 and PCO 2 between arterial and arterialized earlobe samples. A. Sauty, C. Uldry, L-F. Debétaz, P. Leuenberger, J-W. Fitting. ©ERS Journals Ltd 1996. ABSTRACT: Arterialized ear lobe blood samples have been described as adequate to gauge gas exchange in acute and chronically ill patients. It is a safe procedure, usually performed by medical technicians. We have conducted a prospective study to verify the validity of this method.One hundred and fifteen consecutive adult patients were studied. Blood samples were drawn simultaneously from arterialized earlobe and radial artery. Values of partial pressure of oxygen (PO 2 ) and of carbon dioxide (PCO 2 ) were measured by means of blood gas electrodes.The correlation coefficients between the two samples were 0.928 for PO 2 and 0.957 for PCO 2 values. In spite of a highly significant correlation, the limits of agreement between the two methods were wide for PO 2 . Earlobe values of PO 2 were usually lower than arterial values, with larger differences in the range of normal arterial PO 2 . On the other hand, the error and the limits of agreement were smaller for PCO 2 .We conclude that, in adult patients, arterialized earlobe blood PO 2 is not a reliable mirror of arterial PO 2 . Eur Respir J., 1996, 9: 186-189 Blood gas values can be measured using arterialized earlobe blood samples, instead of arterial samples, in order to gauge pulmonary gas exchange in acute or chronically ill patients. This method, described many years ago [1], is a simple and safe procedure which can be performed by medical technicians. Comparing values for partial pressure of oxygen (PO 2 ) and of carbon dioxide (PCO 2 ) from arterialized earlobe blood samples with arterial blood samples, several authors have concluded that the earlobe site was suitable for routine clinical purposes [1][2][3][4][5][6][7][8][9]. This idea was again advocated by two recent studies. PITKIN et al. [10] compared PO 2 , PCO 2 , and pH values from 40 blood samples simultaneously drawn from the radial artery and hyperaemic earlobe. Using the method of BLAND and ALTMAN [11] for the assessment of agreement, these authors also concluded that arterialized earlobe blood gas values were accurate enough to be used in clinical application. Finally, DAR et al. [12] reported that earlobe sampling was significantly less painful than arterial sampling in 55 patients, whereas blood gas values were not different with the two techniques.For several years, the arterialized earlobe technique has been the standard practice for measuring arterial blood gases in our pulmonary function laboratory. However, in some instances, we have noticed a marked discrepancy between arterial and relatively lower arterialized earlobe values of PO 2 . We, therefore, conducted a prospective study to compare arterial and arterialized earlobe blood samples in 115 consecutive adult patients. Material and methodsOur study group included 115 consecutive adult patients investigated in our pulmonary function laboratory for various conditions. No...

In subjects with normal lung mechanics, inspiratory muscle strength can be reliably and easily assessed by the sniff nasal inspiratory pressure (SNIP), which is the pressure measured in an occluded nostril during a maximal sniff performed through the contralateral nostril. The aim of this study was to assess the validity of the SNIP in patients with chronic obstructive pulmonary disease (COPD), where pressure transmission from alveoli to upper airways is likely to be dampened.Twenty eight patients with COPD were studied (mean forced expiratory volume in one second (FEV1) = 36% of predicted). The SNIP and the sniff oesophageal pressure (sniff Poes) were measured simultaneously during maximal sniffs, and were compared to the maximal inspiratory pressure obtained against an occlusion (MIP). All measurements were performed from functional residual capacity in the sitting position.The ratio SNIP/sniff Poes was 0.80, and did not correlate with the degree of airflow limitation. The ratio MIP/sniff Poes was 0.87, and the ratio SNIP/MIP was 0.97. Inspiratory muscle weakness, as defined by a low sniff Poes, was present in 17 of the 28 patients. A false diagnosis of weakness was made in eight patients when MIP was considered alone, in four when SNIP was considered alone, and in only three patients when MIP and SNIP were combined.We conclude that both the sniff nasal inspiratory pressure and the maximal inspiratory pressure moderately underestimate sniff oesophageal pressure in chronic obstructive pulmonary disease. Although suboptimal in this condition, the sniff nasal inspiratory pressure appears useful to complement the maximal inspiratory pressure for assessing inspiratory muscle strength in patients with chronic obstructive pulmonary disease.

Background-Education programmes for adults with asthma vary widely. Such variability suggests a lack of consensus on what works and what does not. The objectives of this paper are to describe asthma education programmes and assess their variability. Methods-A systematic review of reports published between 1979 and 1998 was conducted. Medline, the CINAHL database, the PsycINFO database, the Cochrane collaboration database, the Dissertation Index database, and cross referencing were used to identify educational interventions; 77 projects including 94 interventions that involved 7953 patients were analysed. A standard form was used to record characteristics of studies (design, setting, size, year, and country of publication), projects (theoretical framework, objectives), and education (methods, duration, intensity, educator, and content). Results-Most reports did not specify the general (56%) and educational objectives (60%) of the intervention. Important training characteristics were often not available: duration of education (45%) and number of sessions (22%), who delivered education (15%), whether training was conducted in groups or was individualised (28%). When this information was available there were wide variations in training methods and content: training duration ranged from 0 (self-education) to 58 hours and the number of sessions from 0 to 36; training tools such as peak flow meters, diary cards or books were used in various proportions of interventions (19%, 27%, and 23%, respectively). The content of education also diVered widely between programmes. Conclusions-InsuYcient documentation of asthma education programmes for adults precludes their replication. This, together with excessive variability, reduces the possibility of identifying their most eVective components. A more systematic description of asthma training programmes should be promoted. (Thorax 1999;54:681-687) Keywords: asthma; patient education; self-management Education programmes for people with asthma have existed for a long time but what exactly "patient education" stands for remains elusive. Even a cursory overview of education programmes for asthma patients reveals that programmes vary widely in objectives, educational methods, intensity and duration, educator, and content. Such variability suggests a lack of consensus on what works and what does not in patient education.1 It precludes a meaningful evaluation of the overall eVectiveness of educating asthma patients such as could be achieved by a meta-analysis. Intervention variability has been a minor concern of previously published reviews.2 3 We therefore conducted a systematic review of published educational interventions for adults with asthma with the objective of describing asthma education programmes and assessing their variability. Methods IDENTIFICATION AND SELECTION OF STUDIESTo identify relevant studies we applied the algorithm "asthma and (education or training or self management)" to the Medline database , the Dissertation Index database , the Nursing and Allie...