Design and analysis of health products and services: An example at a specialized COPD unit

Effectiveness of unattended ambulatory sleep studies for the diagnosis and treatment of OSAS

BACKGROUND

Unattended home sleep studies have been implemented to minimize the cost and delay in establishing obstructive sleep apnoea syndrome (OSAS) diagnosis and therapy. However, their accuracy and validity remain disputed. The purpose of our study is to assess their effectiveness (i.e. their technical reliability in real life conditions).

SETTING

Private sleep unit attending to private and social security patients.

POPULATION

Consecutively admitted patients, aged over 18 years, referred to our clinic for confirmation or treatment of OSAS without co-morbidities.

METHODS

A clinical history was obtained for each patient with special attention to sleep, smoking habit, educational level and type of insurance. Chest X-ray and forced spirometry were performed. For the portable respiratory recording device an eight-channel polygraph was used and for continuous positive airway pressure (CPAP) titration an automatic positive airway pressure device was applied; both instruments were previously validated. Patients were instructed how to use the devices at the clinic and then applied them at home by themselves.

RESULTS

For diagnostic sleep studies, 145 out of 150 (96.7%: CI: 92.4-98.9) and for CPAP titration 42 out of the 61 patients (69%: CI: 56.4-81.3) performed the sleep study correctly according to the pre-established criteria. No statistically significant differences were found between correct performance and educational level, sex, smoking habit or type of health insurance.

CONCLUSIONS

(1) Unattended home sleep studies appear as effective as in-hospital studies for diagnosis of OSAS without co-morbidities; (2) for CPAP titration, the effectiveness was slightly lower; and (3) factors such as patients' educational level or type of health insurance do not appear to influence outcome.

State-of-the-art sensor technology in Spain: invasive and non-invasive techniques for monitoring respiratory variables

The interest in measuring physiological parameters (especially arterial blood gases) has grown progressively in parallel to the development of new technologies. Physiological parameters were first measured invasively and at discrete time points; however, it was clearly desirable to measure them continuously and non-invasively. The development of intensive care units promoted the use of ventilators via oral intubation ventilators via oral intubation and mechanical respiratory variables were progressively studied. Later, the knowledge gained in the hospital was applied to out-of-hospital management. In the present paper we review the invasive and non-invasive techniques for monitoring respiratory variables.

Optimal clinical time for reliable measurement of transcutaneous CO2 with ear probes: counterbalancing overshoot and the vasodilatation effect

OBJECTIVES:

To determine the optimal clinical reading time for the transcutaneous measurement of oxygen saturation (SpO₂) and transcutaneous CO₂ (TcPCO₂) in awake spontaneously breathing individuals, considering the overshoot phenomenon (transient overestimation of arterial PaCO₂).

EXPERIMENTAL SECTION:

Observational study of 91 (75 men) individuals undergoing forced spirometry, measurement of SpO₂ and TcPCO₂ with the SenTec monitor every two minutes until minute 20 and arterial blood gas (ABG) analysis. Overshoot severity: (a) mild (0.1–1.9 mm Hg); (b) moderate (2–4.9 mm Hg); (c) severe: (>5 mm Hg). The mean difference was calculated for SpO₂ and TcPCO₂ and arterial values of PaCO₂ and SpO₂. The intraclass correlation coefficient (ICC) between monitor readings and blood values was calculated as a measure of agreement.

RESULTS:

The mean age was 63.1 ± 11.8 years. Spirometric values: FVC: 75.4 ± 6.2%; FEV₁: 72.9 ± 23.9%; FEV₁/FVC: 70 ± 15.5%. ABG: PaO₂: 82.6 ± 13.2; PaCO₂: 39.9.1 ± 4.8 mmHg; SaO₂: 95.3 ± 4.4%. Overshoot analysis: overshoot was mild in 33 (36.3%) patients, moderate in 20 (22%) and severe in nine (10%); no overshoot was observed in 29 (31%) patients. The lowest mean differences between arterial blood gas and TcPCO₂ was −0.57 mmHg at minute 10, although the highest ICC was obtained at minutes 12 and 14 (>0.8). The overshoot lost its influence after minute 12. For SpO₂, measurements were reliable at minute 2.

CONCLUSIONS:

The optimal clinical reading measurement recommended for the ear lobe TcPCO₂ measurement ranges between minute 12 and 14. The SpO₂ measurement can be performed at minute 2.

Intravenous cyclophosphamide pulse therapy in the treatment of systemic sclerosis-related interstitial lung disease: a long term study

OBJECTIVE

Interstitial lung disease (ILD) frequently complicates systemic sclerosis (SSc). Cyclophosphamide (CYC) is a promising immunosuppressive therapy for SSc-related ILD. Our objective was to investigate the effectiveness of an intravenous CYC (iv CYC) pulse regime in SSc-related ILD during treatment and thereafter.

METHODS

In a prospective observational study ten consecutive patients with SSc-related ILD were treated with iv CYC in a pulse regime lasting from 6 to 24 months. Clinical status, pulmonary functional testing (PFT) and high resolution computed tomography (HRCT) of the chest were evaluated at enrolment and 6, 12 and 24 months thereafter. After treatment withdrawal, patients were followed up every 6 months with PFT and chest HRCT to monitor lung disease.

RESULTS

Clinical improvement was apparent in 8 out of 10 patients. The median values of forced vital capacity (FVC), forced expiratory volume in the first second (FEV1) and diffusion lung capacity for carbon monoxide (DLCO) as well as ground-glass pattern on HRCT did not change significantly after 6, 12 and 24 months of therapy. The follow-up continued in 8 out of 10 patients after treatment withdrawal for a median of 26.5 months (range: 12-48 months). The final median FVC was 54.5% of predicted value (interquartile range, IQR= 31.6%-94%). Only one patient suffered a FVC deterioration greater than 10%, even though less than 160 ml. The final median DLCO was 68% of predicted value (IQR=38.3-83.6%). Only 2 patients who developed pulmonary arterial hypertension deteriorated their DLCO values of more than 15%.

CONCLUSIONS

An iv CYC pulse regimen over 24 months may stabilize pulmonary activity in patients with SSc-related ILD during the course of treatment and for a median of 26.5 months thereafter.