Comparison of a new desktop spirometer (Diagnosa) with a laboratory spirometer.

BACKGROUND: The Diagnosa is a fully integrated system, able to determine spirometry, ECG, blood pressure and body composition. Real time data can be transferred via Internet to a remote receiving center. OBJECTIVES: The aim of this study was to perform biological testing of the spirometry component in subjects with normal and pathological pulmonary function. METHODS: A group of 45 patients (mean age 43.3 years, 30 males) was tested on both the Diagnosa and the standard Jaeger Masterlab spirometer according to the guidelines of the American Thoracic Society. Three subgroups of 15 subjects each (normal spirometry, obstructive and restrictive airflow limitation) were selected. RESULTS: All measurements performed with the Diagnosa (FVC, FIVC, FEV(1), PEF, FEF(25), FEF(50), FEF(75)) correlated closely (r = 0.92-0.99) with those performed with the Jaeger spirometer and showed good limits of agreement (the largest difference between the two devices being 0.2 liter for FEV(1)). Analysis of the 3 subgroups showed no difference for any parameters compared to the overall group. Electronic transfer of all data was successful. CONCLUSIONS: The Diagnosa spirometer is comparable to a standard laboratory spirometer and can be used reliably for telemedicine purposes.     

Clinical comparison of two electronic spirometers with a water-sealed spirometer.

Two electronic spirometers which use a hot-wire anemometer to measure air flow were clinically compared with a water-sealed spirometer. The forced vital capacity (FVC), the forced expiratory volume in one second (FEV1), the FEV1/FVC%, the mean forced expiratory flow between 200 and 1,200 ml of the FVC, the mean forced expiratory flow during the middle half of the FVC, the mean forced expiratory flow between 75 and 85 percent of the FVC, and the maximum voluntary ventilation were determined for a group of 67 subjects. Techniques are described for connecting the spirometers in series to permit evaluation by human subjects or by syringe injection. High correlation coefficients generally were obtained when comparing the electronic spirometers with the water-sealed spirometer, but the actual range of percent difference was greater than 11 percent in all spirometric tests. The results indicate the need for systematic evaluation of electronic spirometers to characterize their deviation from accented standards. Frequent calibration is necessary to maintain consistent performance.     

Relevance of a portable spirometer for detection of small airways obstruction

While portable spirometers are increasingly used, little attention has been paid to test their validity for measurement of flows in small airways. The aim of this study was to compare the Spirotel portable spirometer to a laboratory spirometer (Jeager PFT), with regard to accuracy in measuring forced expiratory flows, and more specifically those influenced by small airways (FEF(25-75)). Fifty-nine children (mean age, 12 years; range, 7-17), were studied at baseline and after a bronchodilator inhalation. Spirometers were tested separately in a randomly designed order. A total of 117 sessions of flow-volume curves was performed with each spirometer. We obtained at least two acceptable and reproducible curves in 88% and 76% of the sessions, with the laboratory and the portable spirometers, respectively. Unacceptable curves were easily detected by visual inspection of flow-time and flow-volume waveforms. Agreement was excellent between spirometers for the measurement of all expiratory flows, both at baseline and postbronchodilator. More specifically, agreement between spirometers was as high for measurements of FEF(25-75) (intraclass correlation coefficients 0.97) as for proximal flows. High correlations were found between baseline expiratory flows measured by each spirometer (and expressed as percent of predicted values), both in large and small airways (P < 0.001). The portable spirometer was highly sensitive for detecting small airways obstruction, as compared to the laboratory spirometer. Finally, the magnitudes of bronchodilator-related flow changes were also highly correlated, both in large and small airways (P < 0.001 and P = 0.004, respectively). We conclude that the Spirotel portable spirometer is reliable for measurement of forced expiratory flows, in large and small airways, provided that all curve waveforms can be stored and available for visual inspection.     

Evaluating the use of a portable spirometer in a study of pediatric asthma

STUDY OBJECTIVES: Laboratory-based spirometry is the "gold standard" for the assessment of lung function, both in clinical and research protocols. These spirometers, however, are neither practical nor affordable for home-based monitoring or studies that collect data in multiple locations. Traditionally, peak flowmeters have been used, but they have important limitations. DESIGN: Based on data from a cohort of 92 children with asthma, we evaluated the agreement between a portable spirometer and a office-based spirometer, using an in-line technique to evaluate measures from the same effort. We compared a range of pulmonary function parameters collected during office-based tests, and also evaluated whether adequate adherence and data quality could be achieved in a home-based study of children with asthma. RESULTS: The agreement between the devices for the actual values of peak expiratory flow, FEV(1), and forced expiratory flow at 25% of FVC was excellent. The portable device was programmed with customized software to grade each curve using revised American Thoracic Society acceptability and reproducibility criteria. For 74% of the curves, quality grade agreed with a grade assigned by physician review of the curve from the office-based spirometer. During 2 weeks of twice-daily monitoring at home, children completed an average of 23 of 28 possible sessions (83%). Of these, 84% had at least two acceptable and two reproducible curves. Although children >or= 8 years old were not more adherent, they were significantly more likely to achieve acceptable and reproducible curves. CONCLUSIONS: Portable spirometers can provide measurements that are highly comparable to those obtained from "gold standard" laboratory spirometers, and high-quality tracings can be achieved both at home and in the office setting. Visual inspection of the curves by experienced reviewers identified unacceptable curves that were not rejected by the quality control software. Portable spirometers are an important contribution to epidemiologic and clinical studies that require frequent measures of a more broad range of pulmonary function parameters than can be provided by peak flowmeters.     

Automated interpretation of the pulmonary function test by a portable spirometer in Chinese adults

IntroductionA portable spirometer is a promising alternative to a traditional pulmonary function test (PFT) spirometer for respiratory function evaluation.ObjectivesThis study aimed to investigate the accuracy of automated interpretation of the PFT measured by a portable Yue Cloud spirometer in Chinese adults.MethodsThe PFT was performed to evaluate subjects prospectively enrolled at Ruijin Hospital (n = 220). A Yue Cloud spirometer and a conventional Jaeger MasterScreen device were applied to each patient with a 20‐min quiescent period between each measurement. Pulmonary function parameters, including forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), peak expiratory flow (PEF), maximal expiratory flow at 25%, 50%, and 75% of the FVC (MEF25, MEF50, and MEF75, respectively), and maximal mid‐expiratory flow (MMEF), were compared by correlation analyses and Bland–Altman methods. The Yue Cloud spirometer automatically interpreted the PFT results, and a conventional strategy was performed to interpret the PFT results obtained by the Jaeger machine. Concordance of the categorization of pulmonary dysfunction, small airway dysfunction, and severity was analyzed by the kappa (κ) statistic.ResultsSignificantly similar correlations of all variables measured with the two spirometers were observed (all p < 0.001). No significant bias was observed in any of the measured spirometer variables. A satisfactory concordance of pulmonary function and severity classification was observed between the automated interpretation results obtained with the Yue Cloud spirometer vs. a conventional spirometer interpretation strategy (all κ > 0.80).ConclusionThe portable Yue Cloud spirometer not only yields reliable measurements of pulmonary function but also can automatically interpret the PFT results.     

Flow-volume measurements with a spirometer

All information in the flow-volume curve should be present in the forced expired volume curve recorded with a high fidelity spirometer. This hypothesis was tested by comparing \(\mathop V\limits^ \bullet \) max25 (the flow at RV + 25% VC) measured from flow-volume curves obtained with a pneumotachograph system and an X-Y-oscilloscope with \(\mathop V\limits^ \bullet \) max 25 measured from a forced expirogram recorded with a high fidelity spirometer. The flow at RV + 25% VC was derived by a line drawn through two points on the spirogram at ±0.1 sec. from this volume. Measurements were made on repeated identical FEV blows with different flow rates from an FEV simulator and on exhalations with various flows from two healthy volunteers. The reproducibility was equally good with both methods but a constant error was present in the pneumotachograph measurements (calibration error). In 50 healthy children \(\mathop V\limits^ \bullet \) max 25/TLC obtained with a spirometer had the same magnitude and variability as found by previous authors using conventional flow volume records from a pneumotachograph system.     

Assessment of accuracy and applicability of a portable electronic diary card spirometer for asthma treatment

A pocked-sized turbine flowmeter and spirometer device, integrated with an electronic diary card (EDC-spirometer, Micro Medical, U.K.), was tested with a mechanical calibrator, in an outpatient clinic and in the home situation. A screen pneumotachometer was used as flow and volume reference.Ten devices were tested; interdevice variability was small with a mean variation coefficient of 1·1% for both forced expiratory volume in 1 s (FEV₁) and peak expiratory flow (PEF) ( 0·5 and 0·4, respectively) for eight settings of the calibrator. Mean difference from reference was −0·131 ( 0·04) for FEV₁ (range 0·38–3·16) and 0·091 s⁻¹ ( 0·09) for PEF (range 4·2–11·7). No significant deviation from linearity was present.Results obtained in the outpatient clinic confirmed the accuracy of FEV₁ and PEF data obtained with the calibrator. However, linear regression analysis showed a mean underestimation of 0·451 ( of estimate 0·29) for forced vital capacity over the whole measurement range, probably due to a restricted integration time.In 10 optimally-treated chronic obstructive pulmonary disease patients in a family practice, PEF measurements were done in the home situation, both with the EDC spirometer and a mini-Wright peak flow meter. No significant differences in the diurnal variation of PEF were found. The PEF data from the mini-Wright meter were corrected for earlier reported flow-dependent systematic deviations. In the home situation, patients preferred the EDC spirometer. It is concluded that this device is applicable in the follow-up and treatment of asthma at home.     

Arrhythmia surveillance by transtelephonic monitoring: comparison with Holter monitoring in symptomatic ambulatory patients.

We have evaluated a patient-actuated transtelephonic monitoring system (TTM) in order to determine its ability to document the cardiac rhythm at the time of symptoms; results have been compared to a simultaneously recorded 24-hour Holter Monitor (HM).Forty patients submitted an average of 15.6 TTM recordings/patient over a 7-day recording period. Twenty-six patients reported significant symptoms during the period of study: 11 had demonstrated arrhythmias, and these were documented by HM alone in one, by TTM alone in four, and by both HM and TTM in six.In 15 patients, no arrhythmia was seen during symptoms. HM alone was useful in excluding arrhythmia as a cause for the symptoms in two patients, TTM alone in six patients, and both in the remaining seven patients. Cumulative diagnostic usefulness in evaluating the significance of symptoms potentially attributable to arrhythmia is summarized: HM alone useful in three patients, TTM alone useful in 10 patients, and both HM and TTM useful in 13; TTM was significantly more useful than HM (χ² = 3.69; P < 0.05).Of note is that six patients had significant arrhythmias during asymptomatic periods, including VPC's (four), severe sinus bradycardia (one), and rapid atrial fibrillation (one). In these few patients, both techniques appeared equally able to document asymptomatic arrhythmias.These observations demonstrate that TTM carried out over a 7-day period is superior to a 24-hour Holter monitor recording in its ability to establish the significance of symptoms potentially attributable to arrhythmia, and appeared equally sensitive to HM in demonstrating periods of asymptomatic arrhythmia.TTM can therefore be considered a simple, accurate, and useful technique for arrhythmia surveillance in the symptomatic patient.     

Lung function measurement in general practice: a comparison of the Escort spirometer with the Micromed turbine spirometer and the mini-Wright peak flow meter

It is important that new types of spirometer for widespread clinical use are pragmatically evaluated in primary care. This study compared measurements taken by a new portable Fleisch pneumotachograph spirometer (known as the Escort) with those of the commonly used mini-Wright peak flow meter and the Micromed Pocket turbine spirometer. A pragmatic study was conducted in two phases during routine surgeries at Aldermoor Health Centre, Southampton. Phase 1 compared the new spirometer with the mini-Wright peak flow meter and Phase 2 compared the new spirometer and the turbine spirometer. One hundred patients aged 5–88 years (56 patients with a history of chronic respiratory complaints and 44 patients without) entered Phase 1, and 100 patients aged 6–82 years (62 patients with a history of chronic respiratory complaints and 38 patients without) entered Phase 2. Each patient contributed only once to each phase, but some entered both phases on separate occasions. Ninety-five percent limits of agreement (mean ± 2 ) were wide for all comparisons. Graphical plots revealed trends towards higher Escort values as mean values rose compared with both mini-Wright and turbine readings for peak expiratory flow rate and forced expiratory volume in one second. Possible over-reading of peak expiratory flow rate with the mini-Wright meter at low mean values was also seen. Readings taken with these different types of meter cannot be interchanged with confidence in clinical practice. The clinical significance of the theoretically more accurate measures of lung function produced with the new meter, and indeed of spirometry itself, needs further investigation.     

A new sensitive portable plethysmograph

A new portable plethysmograph is described which is all metal and, therefore, sturdy and free from the difficulties of deterioration—an important problem when rubber membranes are employed. A device for standardization is incorporated which makes it possible to correct for finger and toe size, thereby resulting in a completed plethysmogram which can be read directly from subject to subject and from time to time in the same subject. This eliminates calculations usually required to convert volume changes to standard units. The plethysmograph also contains a master elapse time recorder which makes it possible to record time even when the camera is off. By means of a baseline adjuster and recorder, gross or large and slow variations in volume of the part can be recorded.The completed plethysmogram is discussed and five types of spontaneous deflections in volume are considered. The plethysmogram shows the volume changes at slow and fast speeds. The former makes it possible to study all five types of spontaneous deflections in volume, while the latter makes it possible to study the configurations of the pulse wave in detail.A discussion of the methods of recording the plethysmogram, precautions and possible errors in recording, and its interpretation are given. The use of plethysmography in the study of peripheral vascular disease, psychogenic states, and states of relaxation and tension are briefly indicated. Detailed applications of the plethysmogram to normal and abnormal clinical states will be presented in the near future.This plethysmograph is a new instrument which is objective, precise, simple, and practical. It has great promise in the study of many problems in health and disease which manifest themselves by disturbances in the blood vessels, lymphatics, and intercellular and intracellular and fluid volumes of the tips of the fingers and toes. By far the greatest number of experimental and clinical applications remain unknown. As with the introduction of any new instrument which has applications in the biologic fields generally and broad use in these fields, the science is in its infancy. It is only with the patient efforts of many investigators, both in the laboratory and the clinic, that the plethysmograph and plethysmogram will develop and reach a state of adequate evaluation and proper usage.     

A multicentre trial of the diagnostic value and cost of electrocardiography in symptoms suggesting arrhythmia with a new event recorder with transtelephonic transmission

Events recorders are used for electrocardiographic documentation of symptoms of arrhythmia too sporadic and short lasting to be recorded by 24 hour Holter monitoring. However, there are no French studies comparing the value and cost of event recorders with conventional diagnostic methods. Recently, a new telediagnostic device has become available in France leading to an assessment of the technique. The aim of this study was to determine the value of this event recorder and the cost of diagnostic ECG in the assessment of presumed arrhythmic symptoms such as palpitations or rare tachycardia (<3 episodes per week) of short duration, compared with conventional techniques. Fifty-eight patients with these criteria were randomised, 30 to Survcard (Group I) and 28 to conventional diagnostic methods (Group II). The patients were comparable with respect to age, sex distribution, type of symptoms and associated cardiac disease. The ECG diagnosis of the symptoms was established in 20 cases (66.6%) of patients in Group I in 17 +/- 16 days, and in 14 cases (50.0%) of Group II in 23 +/- 28 days. The difference between the two groups was not statistically significant. The cost of a positive diagnosis for Group I (Survcard) varied from 0 to 228.47 Euro with an average of 71.22 +/- 117.02 Euro. The cost of positive diagnosis in Group II varied from 76.80 to 2340.41 Euro with an average of 480.39 +/- 797.41 Euro. In conclusion, this study showed that the percentage of patients with a positive diagnosis was comparable in the two groups but that the cost was 6 times higher in the group investigated by conventional methods than in the Survcard group because of more costly medical intervention.     

Use of transtelephonic electrocardiographic monitoring in children with suspected arrhythmias.

Arrhythmias in children can produce various symptoms and their assessment often is difficult with usual methods. Transtelephonic electrocardiographic monitoring was used in 136 symptomatic patients (palpitations [112], syncope [six], chest pain [18]) for a mean duration of 86 +/- 65 days; mean age was 11.1 +/- 4.8 years and 62% were female. Of 398 recordings sent (mean 2.9 per patient) 32 revealed significant arrhythmias (8%). Of the 67 patients reporting symptoms during the recording period, only 24 had documented arrhythmias - 23 supraventricular tachycardia and one junctional tachycardia. The negative predictive value is 100%, compared with a low positive predictive value of 36%; sensitivity and specificity are, respectively, 100 and 62%. Of the 24 patients with documented arrhythmias, 54% were treated versus 13% of those with normal recordings (P < 0.01). At the end of the follow-up (mean duration 1.6 +/- 1.2 years), 63% of the patients with negative recordings had not complained of further symptoms versus 22% of those with documented arrhythmias (P = 0.001). Transtelephonic electrocardiographic monitoring is an important tool for documenting infrequent arrhythmias in children and even more for reassuring the patient and his or her family in the absence of significant arrhythmias.     

A comparison of spirometry in general practice and a pulmonary function laboratory.

AIMS:: To compare the results of spirometry testing in primary care with those obtained at a pulmonary function laboratory and to explore whether differences were due to technique or equipment. METHODS:: Patients on the waiting list for spirometry in six participating practices had the test performed in their own practice and at the pulmonary function laboratory (PFL). RESULTS:: A total of 45 patients had spirometry performed at both locations. Practice nurses underestimated FEV(1) and FVC. The mean difference in FEV(1) was 0.109litres (6.69%, 95% CI 2.88, 9.51) compared with a bellows spirometer, and 0.07litres (6.2% 95% CI 0.89, 8.25) when the same type of spirometer was used. The mean difference in FVC was 0.413litres (15.0% 95% CI 9.3, 20.6) when compared with bellows, and 0.267litres (10.2% 95% CI 4.1, 16.2) when the same type of spirometer was used. All differences were statistically significant (p<0.05, paired t test). Agreement on categorization of COPD was moderate (Kappa 0.46) with practice nurses overestimating severity. Compared to PFL categorisation for the presence or absence of COPD using bellows spirometers, the sensitivity of practice nurse spirometry was 0.93 (95% CI: 0.76, 0.99) and specificity 0.65 (95% CI: 0.38, 0.86). CONCLUSION:: Spirometry results obtained by practice nurses were lower than those obtained in a PFL, leading to over-diagnosis of COPD severity.     

Feasibility and reliability of a transtelephonic 12 leads ECG

Feasibility and reliability of a 12 lead electrocardiogram (ECG), recorded by the patient himself and transmitted via telephone are mandatory for prehospital diagnosis of myocardial ischemia in patients with coronary heart disease. In this study, a 12-lead ECG recorded by patients and transmitted to the cardiology call center via telephone (Tele-ECG; model CG-7100; Card Guard) was compared with the conventional 12-lead ECG from the same patient recorded at the same time in 128 cases. The Tele-ECGs received by the call center were compared with conventional ECG by two cardiologists and one internist independently and blindly. In relation to the conventional ECG, reproducibility of PQ, QRS and QT-durations [ms] as measured in the Tele-ECG was 85%. Concordance between Tele-ECG and conventional ECG in the detection of negative T-waves was very high (Kappa value (kappa) 0.94, 0.96 and 0.97), respectively, depending on the physician. ST-segment changes were diagnosed correctly in most of the cases in Tele-ECG (kappa=0.98-0.99), as compared with the conventional ECG by all physicians. Concordance between Tele- and conventional ECG concerning the pattern of old myocardial infarction was very high (kappa=0.99) for all infarct localization. The limitations of Tele-ECG were of technical nature. In 14 cases, the peripheral electrodes were displaced; in 12 cases, there were baseline artifacts. These technical errors could be corrected in 126/128 patients (98.4%) by transtelephonic verbal communication. In conclusion, the reliability and feasibility of the 12-lead Tele-ECG-recorder used in this pilot study could be demonstrated. In an ongoing randomized controlled multicenter study, it is being investigated whether the strategy of prehospital diagnosis of acute coronary syndromes by Tele-ECG in combination with verbal communication is able to reduce pre- and in-hospital time delay, to avoid unnecessary hospital admissions and to reduce the economic burden of coronary heart disease.     

Evaluation of outpatient arrhythmias utilizing transtelephonic monitoring.

This study demonstrates the inaccuracy of the presumptive clinical diagnosis of cardiac arrhythmia. Not only are physicians often wrong in establishing diagnosis on clinical grounds, in addition, a significant number of patients have symptoms which have been attributed to a cardiac basis when in fact, no rhythm abnormality exists. For this reason, electrocardiographic documentation is essential. This study defines the usefulness of transtelephonic monitoring in evaluating cardiac rhythm during a symptomatic episode suggestive of arrhythmia. It also defines the limitations of transtelephonic monitoring in patients whose symptoms are too brief or who would find the system awkward to use.     

A comparison between capillary and venous blood international normalized ratio determinations in a portable prothrombin time device.

The CoaguChek PT system is a portable point-of-care device for prothrombin time testing that can be used with capillary and venous whole blood. This system had been calibrated by the manufacturer in terms of the international normalized ratio (INR) for monitoring oral anticoagulant therapy. The purpose of the present study was to compare capillary blood with venous blood INRs from healthy volunteers and patients treated with oral anticoagulants using the same CoaguChek PT system. Two different CoaguChek PT strip formulations [international sensitivity index (ISI), 1.5 and 1.1] were used in separate test series. The differences between capillary and venous blood INRs were statistically significant (P < 0.001) but the magnitude of the differences was small. The mean relative deviations of the INR were 5.8 and 2.8% for the strips with ISI 1.5 and 1.1, respectively. These deviations are clinically acceptable. It is concluded that capillary blood can be replaced by venous blood for the calibration of the CoaguChek PT system.