The use of portable monitoring for sleep apnea diagnosis in adults

Low-Cost Photoelectric Flow Rate Sensors Based on a Flexible Planar Curved Beam Structure for Clinical Treatments

In clinical treatments, reliable flow rate measurements ensure accurate drug delivery during infusions, precise gas delivery during artificial ventilations, etc., thereby reducing patient morbidity and mortality. However, precise flow rate sensors are costly, so medical devices with limited budgets choose cheaper but unsatisfactory flow rate measurement approaches, leading to increased medical risks. Here, a photoelectric flow rate sensor based on a flexible planar curved beam structure (FPCBS) is proposed. The FPCBS ensures low out-of-plane stiffness of the sensitive sheet and allows large deformation in the elastic range, enabling the flow rate sensor to measure the flow rate with high sensitivity over a wide range. Meanwhile, the flow rate sensor can be mass-produced using mature materials and manufacturing technology at less than $5 each. The flow rate sensors are integrated into a commercial infusion pump to measure drug infusion and a home ventilator to monitor respiration. The results are comparable to those measured by a commercial flow rate sensor, demonstrating the applicability of the sensor. Considering its proven outstanding performance at low cost, the flow rate sensor shows great potential in clinical treatment, medical diagnosis, and other medical fields.

Diagnostic accuracy of nasal cannula versus microphone for detection of snoring

OBJECTIVE

Snoring is a common reason for referral to a sleep unit. Although there are several instruments to measure snoring, there is no gold standard for this purpose. In this study, we determine the diagnostic accuracy of the cannula as compared with the microphone, which are the two most commonly used tools.

STUDY DESIGN

We performed a cross-sectional study of 75 patients who underwent baseline home sleep apnea testing for any reason.

METHODS

Snore intensity and percentage were assessed during Home sleep-apnea testing via nasal cannula and microphone in all patients. We performed a complete diagnostic accuracy analysis, assuming the microphone to be the reference instrument use in order to compare it with the cannula.

RESULTS

The intra-class correlation coefficient between the cannula and microphone for the percentage of snoring was 0.25. The Bland Bland-Altman analysis to determine the agreement regarding the percentage of snoring showed a lower limit of -57.73 and an upper limit of 20.30. A linear regression analysis of the differences produced a negative slope of -0.86. The receiver operating characteristic curve for severe snoring using the cannula produced an area under the curve of 0.67 (P = 0.019). The cannula showed a sensitivity of 57.89 and a specificity of 73.21.

CONCLUSION

The nasal cannula showed poor reliability and accuracy for measuring snoring.

LEVEL OF EVIDENCE

2b. Laryngoscope, 127:2886-2890, 2017.

Diagnostic accuracy of home-based monitoring system in morbidly obese patients with high risk for sleep apnea

BACKGROUND

No previous studies have validated the use of portable monitoring (PM) for the diagnosis of obstructive sleep apnea (OSA) in morbidly obese individuals. Our aim was to investigate the accuracy of PM for detecting respiratory events in morbidly obese patients that will be undergoing bariatric surgery.

METHODS

This was a prospective study involving patients with body mass index (BMI) ≥35 kg/m(2) who were recruited from the Sleep Clinic of Universidade Federal de São Paulo. Sleep-disordered breathing (SDB) was evaluated during full-night polysomnography (PSG). PM use was randomized and used on two consecutive nights: (1) at home (STDHome) and (2) at the sleep laboratory with PSG (PSG_STDLab).

RESULTS

Although 58 participants initially underwent the recordings, 26 (45%) were excluded because of technical problems. The patients' mean age was 42.9 ± 10.9 (SD) years, and 56% were female. The mean BMI was 40.8 ± 5.2 kg/m(2). All patients had high risk for OSA, as defined by the Stop-Bang questionnaire, and the mean apnea-hypopnea index (AHI) was 46.9 ± 30.4/h. The intraclass coefficient of the correlation between AHI_PSG and AHI_STDLab was r = 0.92 (p = 0.0001); the intraclass coefficient for AHI_PSG and AHI_STDHome was r = 0.84 (p = 0.0001). The Kappa index was 0.87 (p > 0.0001) for severe cases. The sensitivity and the positive predictive value increased with the disease severity. A Bland-Altman analysis showed good agreement between the investigated methods.

CONCLUSIONS

PM is an efficacious method for diagnosing OSA in obese patients who have a high clinical probability of the disease. The method displays good sensitivity and specificity in severe cases; nevertheless, the high rate of data loss must be taken into account.

Update on the use of portable monitoring system for the diagnosis of sleep apnea in specific population

The prevalence and severity of obstructive sleep apnea (OSA) is higher in specific population: children, elderly, obese and patients with pulmonary and cardiovascular diseases, compared to the general population. OSA is associated with greater morbidity and mortality in these patients. Although full-night polysomnography is still the gold standard diagnostic sleep study for OSA, it is a time consuming, expensive and technically demanding exam. Over the last few years, there is growing evidence on the use of portable monitors (PM) as an alternative for the diagnosis of OSA. These devices were developed specially for sleep evaluation at home, at a familiar environment, with easy self-application of monitoring, unattended. The use of PM is stablished for populations with high pre-test probability of OSA. However, there is a lack of studies on the use of PM in age extremes and patients with comorbidities. The purpose of this review is to present the studies that evaluated the use of PM in specific population, as well as to describe the advantages, limitations and applications of these devices in this particular group of patients. Although the total loss rate of recordings is variable in different studies, the agreement with full-night polysomnography justifies the use of PM in this population.