Monitoring of breathing phases using a bioacoustic method in healthy awake subjects.

OBJECTIVE: To test the ability of a microphone recording system, located distal to the respiratory outflow tract, to track the timing of the inspiratory and expiratory phases of breathing in awake healthy subjects. METHODS: Fifteen subjects participated. Breath sounds were recorded using a microphone embedded in a face frame in a fixed location in relation to the nostrils and mouth, while simultaneously recording respiratory movements by respiratory inductance plethysmography (RIP). Subjects were studied while supine and were instructed to breathe normally for 2 min: through their noses only (nasal breathing), during the first min, and through their mouths only (oral breathing) during the second min. Five subjects (test group) were chosen randomly to extract features from their acoustic data. Ten breaths (5 nasal and 5 oral breaths) from each subject were studied. Inspiratory and expiratory segments of breath sounds were determined and extracted from the acoustic data by comparing it to the RIP trace. Subsequently, the frequency spectrum of each phase was then determined. Spectral variables derived from the 5 test subjects were applied prospectively to detect breathing phases in the remaining 10 subjects (validation group). RESULTS: Test group data showed that the mean of all inspiratory spectra peaked between 30 and 270 Hz, flattened between 300 and 1,100 Hz, and peaked again with a center frequency of 1,400 Hz. The expiratory spectra peaked between 30 and 180 Hz and its power dropped off exponentially after that. Accordingly, the bands ratio (BR) of frequency magnitudes between 500 and 2500 Hz to frequency magnitudes between 0 and 500 Hz was chosen as a feature to distinguish between breathing phases. BR for the mean inspiratory spectrum was 2.27 and for the mean expiratory spectrum was 0.15. The route of breathing did not affect the BR ratio within the same phase. When this BR was applied to 436 breathing phases in the validation group, 424 (97%) were correctly identified (Kappa = 0.96, P < 0.001) indicating strong agreement between the acoustic method and the RIP. CONCLUSION: Frequency spectra of breathing sounds recorded from a face-frame, reliably identified the inspiratory and expiratory phases of breathing. This technique may have various applications for respiratory monitoring and analysis.

The feasibility of an automated monitoring system to improve nurses' hand hygiene.

BACKGROUND: Inadequate hand hygiene (HH) by healthcare staff results in increased rates of hospital acquired infections in healthcare institutions, considerable waste of resources, and negative economic impact for the healthcare system. Toronto Rehabilitation Institute has developed an automated HH monitoring system that detects HH opportunities, generates HH reminding signals when it is necessary and enables hospital management to monitor individual and aggregated HH performance on ongoing basis. OBJECTIVE: To demonstrate that HH improvement is feasible with the proposed technical solution and that technology is acceptable by potential users. METHODS: The technology was installed in four rooms on a nursing unit of a larger complex continuous care hospital. The rooms were selected to make it possible to automatically follow the same nurses for the duration of their entire shift. Eleven nurses were provided with the wearable electronic HH monitors as well as with the instrumented personal wearable alcohol gel dispensers. Stationary gel dispensers installed in the unit were also instrumented with technology. RESULTS: Over 145 h of testing the system automatically recorded a total of 1438 events of entering and leaving monitored rooms and indicated an average of 6.42 HH actions per hour. The baseline observational study indicated 4.2 HH actions per hour. Approximately half of the HH actions recorded by the system were performed using personal wearable alcohol gel dispensers. CONCLUSION: The results obtained when testing the embedded HH monitoring system demonstrated the feasibility of HH improvement and proved that proposed solution merits a larger and longer clinical trial to measure the degree of improvement and the sustainability of that improvement.

Comparison of cumulative low back loads of caregivers when transferring patients using overhead and floor mechanical lifting devices.

BACKGROUND: Mechanical lifting devices are recommended as an important intervention for reducing lifting injuries among nursing personnel; previous research suggests that spinal loads are not minimized for all device types. The purpose of this study was to describe the spinal loading pattern while performing a bed to chair transfer comparing Overhead and Floor powered lifting devices. METHODS: A Latin Square design was employed to evaluate five lifting devices while performing a heavy patient transfer. The primary outcomes were spinal compression, and anterior shear (across median and cumulative loading conditions), and ratings of perceived exertion. An inverse dynamic approach was used to calculate the net joint forces and moments about the L5/S1 spinal level. The transfer was partitioned into seven distinct phases for biomechanical analysis. FINDINGS: The proportion of time spent and the mean loads sustained in each phase of the transfer were described. Significant differences in loads were observed between the differing lifting devices, particularly during the transport phases for the Overhead devices. Nurse subjects consistently ranked Overhead lifting devices as most preferred. INTERPRETATION: A large proportion of the time to complete the transfer and cumulative loads occurred during phases that involved only the sling and not the mechanical component of the device. Overhead lifting devices were shown to have lower spinal loads during the transport phases. The results of this study have implications for the use and selection of mechanical lifting devices as part of a strategy to reduce back injuries.