Search Results (11)

This study investigates the impact of different types of personal protective equipment (PPE), specifically Powered Air-Purifying Respirators (PAPRs) and traditional N95 masks with face shields, on the physiological stress responses of healthcare workers (HWs) during the COVID-19 pandemic. Utilizing an interventional randomized crossover trial design, the research encompasses a simulation phase with ten participants followed by field testing involving thirty frontline healthcare professionals in a tertiary-care hospital setting. Heart rate (HR) and movement data were collected through smartwatches, while trained observers recorded the duration and nature of various activities undertaken during simulations. Data analysis employed statistical techniques, including Principal Component Analysis (PCA) and t-Distributed Stochastic Neighbor Embedding (t-SNE), to explore potential correlations between PPE type, HR, and movement. Clustering validation measures such as the Calinski–Harabasz, Davies–Bouldin, and Silhouette scores were applied to evaluate the difference between each type of PPE. The results indicated no significant differentiation in HR responses between the two PPE types. However, because HR may lack the sensitivity to fully capture variations in cognitive load or stress, these findings should be interpreted as an exploratory baseline. Additionally, no clear distinctions were observed regarding individual user responses or the activities performed, even when considering movement data. Although the findings imply non-inferiority of the examined PPE, future research including heart rate variability as a more comprehensive indicator of stress would be informative. This research contributes valuable insights into PPE selection and its implications for healthcare worker performance and well-being in high-stress environments, ultimately aiming to inform guidelines and training programs to enhance healthcare delivery during infectious disease outbreaks. Full article

In this study, a prototype system was developed as a potential alternative to lockdown measures against the spread of airborne infectious diseases such as COVID-19. The system integrates real-time estimation functions for respiratory flow and mask leakage into a low-cost powered air-purifying respirator (PAPR) designed for the general public. Using only a single differential-pressure sensor (SDP810) and a controller (Arduino UNO R4 WiFi), the respiratory flow (Q_3e) is estimated from the differential pressure (ΔP) and battery voltage (V_b), and both the wearing status and leak status are transmitted to and displayed on a smartphone application. For evaluation, a testbench called the Respiratory Airflow Testbench was constructed by connecting a cylinder–piston drive to a mannequin head to simulate realistic wearing conditions. The estimated respiratory flow Q_3e, calculated solely from ΔP and V_b, showed high agreement with the measured flow Q_3m obtained from a reference flow sensor, confirming the effectiveness of the estimation algorithm. Furthermore, an automatic leak detection method based on the time-integrated value of Q_3e was implemented, enabling the detection of improper wearing. This system thus achieves respiratory flow estimation and leakage detection based only on ΔP and V_b. In the future, it is expected to be extended to applications such as pressure control synchronized with breathing activity and health monitoring based on respiratory and coughing analysis. This platform also has the potential to serve as the foundation of a PAPR Wearing Status Network Management System, which will contribute to societal-level infection control through the networked sharing of wearing status information. Full article

The aim of this study was to analyse the Western Australian (WA) Safety Regulatory System (SRS) database to assess compliance of the WA mining sector regarding workers exposure to welding fumes and to identify trends over time. De-identified data analysed to assess the impact of reducing workplace exposure standards (WES) for general welding fumes on industry compliance. Historical trend analysis shows a shift from 100% compliance to 100% non-compliance, based on mean values and 95% confidence intervals, with exposure levels remaining consistent over time. These findings highlight the need for current, innovative engineering solutions, and raise questions about the validity of current sampling methods. Powered air-purifying respirators (PAPRs) integrated with welding helmets can reduce exposures by up to 99.96%, making their adoption as industry best practice critical, yet current sampling methodologies measure welding fume levels outside PAPRs, thus potentially misclassifying workers who are adequately protected as non-compliant. The sampling method is also influenced by other particulate matter present in the workplace that may be due to grinding or other dust generating activities in the vicinity of the welder. Lower WES values necessitate a review of exposure assessment and reporting methods to accurately reflect worker exposures. Full article

Fluid dynamics modeling was conducted for the supply unit of a Powered Air-Purifying Respirator (PAPR) consisting of a nonwoven fabric filter and a pump, as well as for the exhaust filter (nonwoven fabric). The supply flow rate Q₁ was modeled as a function of the differential pressure ΔP and the duty value d of the PWM control under a constant pump voltage of V = 12.0 [V]. In contrast, the exhaust flow rate Q₂ was modeled solely as a function of ΔP. To simulate the pressurized hood compartment of the PAPR, a pressure buffer and a connected “respiratory airflow simulator” (a piston–cylinder mechanism) were developed. The supply unit and exhaust filter were connected to this pressure buffer, and simulated respiratory flow was introduced as an external disturbance flow. Under these conditions, it was demonstrated that the respiratory state—i.e., the expiratory state (flow from the simulator to the pressure buffer) and the inspiratory state (flow from the pressure buffer to the simulator)—can be estimated from the differential pressure ΔP, the pump voltage V, and the PWM duty value d, with respect to the disturbance flow generated by the respiratory airflow simulator. It was also confirmed that such respiratory state estimation remains valid even when the duty value d of the pump is being actively modulated to control the internal pressure of the PAPR hood. Furthermore, based on the estimated respiratory states, a theoretical investigation was conducted on constant pressure control inside the PAPR and on the inverse pressure control aimed at supporting respiratory activity—namely, pressure control that assists breathing by depressurizing when expiratory motion is detected and pressurizing when inspiratory motion is detected. This study was conducted as part of a research and development project on public-oriented PAPR systems, which are being explored as alternatives to lockdown measures in response to airborne infectious diseases such as COVID-19. The present work specifically focused on improving the wearing comfort of the PAPR. Full article

As the core power element of a centrifugal fan, the impeller’s structural parameters are important factors affecting the aerodynamic performance of the fan. Therefore, to improve the aerodynamic performance of centrifugal fans, in this study, we take the Powered Air-Purifying Respirator (PAPR) power system as the object of research and use a combination of computational fluid dynamics (CFD) and experimental validation to investigate the effects of the number of blades, blade inlet angle, blade outlet angle, blade height, and blade thickness on the aerodynamic performance of the fan. A five-factor, four-level orthogonal test table L₁₆ (4⁵) was selected to obtain the optimal combination of structural parameters for the impeller. In addition, in order to identify and visualize the features of the vortex, Q Criterion Normalized is applied to the simulation on the basis that the minimum pressure appears in the vortex core. In this study, Q Criterion Normalized is used to compare the internal vorticity of the prototype with that of the optimized prototype. The results show that (i) the order of influence of each parameter on the aerodynamic performance of the centrifugal fan is blade height > blade outlet angle > blade inlet angle > number of blades > blade thickness; (ii) the optimal combination of the structural parameters is number of blades 48, blade inlet angle 80°, blade outlet angle 120°, blade thickness 0.6 mm, and blade height 23 mm; the optimized prototype has an increase in air pressure of about 10%, an increase in air volume of about 31%, and an increase in efficiency from 49.61% to 53.57%; (iii) the intensity of internal vortices in the optimized prototype is weakened, the size of vortices and the number of vortices are reduced, and the homogeneity of the flow field is also improved. Full article

This study aimed to compare the accuracy of real-time trans-tracheal ultrasound (TTUS) with capnography to confirm intubation in cardiopulmonary resuscitation (CPR) while wearing a powered air-purifying respirator (PAPR). This setting reflects increased caution due to contagious diseases. This single-center, prospective, comparative study enrolled patients requiring CPR while wearing a PAPR who visited the emergency department of a tertiary medical center from December 2020 to August 2022. A physician performed the TTUS in real time and recorded the tube placement assessment. Another healthcare provider attached waveform capnography to the tube and recorded end-tidal carbon dioxide (EtCO₂) after five ventilations. The accuracy and agreement of both methods compared with direct laryngoscopic visualization of tube placement, and the time taken by both methods was evaluated. Thirty-three patients with cardiac arrest were analyzed. TTUS confirmed tube placement with 100% accuracy, sensitivity, and specificity, whereas capnography demonstrated 97% accuracy, 96.8% sensitivity, and 100% specificity. The Kappa values for TTUS and capnography compared to direct visualization were 1.0 and 0.7843, respectively. EtCO₂ was measured in 45 (37–59) seconds (median (interquartile range)), whereas TTUS required only 12 (8–23) seconds, indicating that TTUS was significantly faster (p < 0.001). No significant correlation was found between the physician’s TTUS proficiency and image acquisition time. This study demonstrated that TTUS is more accurate and faster than EtCO₂ measurement for confirming endotracheal tube placement during CPR, particularly in the context of PAPR usage in pandemic conditions. Full article

Welding fume is generated during welding activities and is a known cancer-causing hazard for those working in the welding industry. Worker exposure has been shown to regularly exceed the applicable workplace exposure standard, and control measures are required to reduce worker exposure. The aim of this study is to compare the effectiveness of control measures to prevent welding fume exposure to workers. To achieve this aim, three common welding fume control measures (local exhaust ventilation (LEV), powered air purifying respirators (PAPRs) and on-gun extraction) were used during four different welding tasks. Compared to using no controls, LEV hood capture is likely to reduce welding fume concentrations in the breathing zone of a welder by up to a factor of 9. The use of on-gun LEV is likely to reduce welding fume concentrations in the breathing zone of a welder by up to a factor of 12. The 5th percentile effective protection factors of the PAPR for all sampled welding activities were considerably greater than the required minimum protection factor of 50 specified in AS/NZS 1715:2009 for powered air purifying respirators (PAPRs) with class PAPR-P3 particulate filters with any head covering. Full article

(1) Background: The perception of others’ emotions based on non-verbal cues, such as facial expressions, is fundamental for interpersonal communication and mutual support. Using personal protection equipment (PPE) in a work environment during the SAR-CoV-2 pandemic challenged health professionals’ ability to recognise emotions and expressions while wearing PPE. The working hypothesis of this study was that the increased limitation of facial visibility, due to the use of a personal protective device, would interfere with the perception of basic emotions in the participants. (2) Methods: Through a cross-sectional descriptive study, the present research aimed to analyse the identification of four basic emotions (happiness; sadness; fear/surprise; and disgust/anger) through three types of PPE (FFP2 respirator, protective overall and powered air-purifying respirator (PAPR)), by using 32 photographs. The study was conducted using volunteer participants who met the inclusion criteria (individuals older than 13 without cognitive limitations). Participants had to recognise the emotions of actors in photographs that were randomly displayed in an online form. (3) Results: In general, the 690 participants better recognised happiness and fear, independently of the PPE utilised. Women could better identify different emotions, along with university graduates and young and middle-aged adults. Emotional identification was at its worst when the participants wore protective overalls (5.42 ± 1.22), followed by the PAPR (5.83 ± 1.38); the best scores were obtained using the FFP2 masks (6.57 ± 1.20). Sadness was the least recognised emotion, regardless of age. (4) Conclusions: The personal protective devices interfere in the recognition of emotions, with the protective overalls having the greatest impact, and the FFP2 mask the least. The emotions that were best recognised were happiness and fear/surprise, while the least recognised emotion was sadness. Women were better at identifying emotions, as well as participants with higher education, and young and middle-aged adults. Full article

Background and Objectives: This retrospective study evaluated the clinical impact of enhanced personal protective equipment (PPE) on the clinical outcomes in patients with out-of-hospital cardiac arrest. Moreover, by focusing on the use of a powered air-purifying respirator (PAPR), we investigated the medical personnel’s perceptions of wearing PAPR during cardiopulmonary resuscitation. Materials and Methods: According to the arrival time at the emergency department, the patients were categorized into a conventional PPE group (1 August 2019 to 20 January 2020) and an enhanced PPE group (21 January 2020, to 31 August 2020). The primary outcomes of this analysis were the return of spontaneous circulation (ROSC) rate. Additionally, subjective perception of the medical staff regarding the effect of wearing enhanced PPE during cardiopulmonary resuscitation (CPR) was evaluated by conducting a survey. Results: This study included 130 out-of-hospital cardiac arrest (OHCA) patients, with 73 and 57 patients in the conventional and enhanced PPE groups, respectively. The median time intervals to first intubation and to report the first arterial blood gas analysis results were longer in the enhanced PPE group than in the conventional PPE group (3 min vs. 2 min; p = 0.020 and 8 min vs. 3 min; p < 0.001, respectively). However, there were no significant differences in the ROSC rate (odds ratio (OR) = 0.79, 95% confidence interval (CI): 0.38–1.67; p = 0.542) and 1 month survival (OR 0.38, 95% CI: 0.07–2.10; p = 0.266) between the two groups. In total, 67 emergent department (ED) professionals responded to the questionnaire. Although a significant number of respondents experienced inconveniences with PAPR use, they agreed that PAPR was necessary during the CPR procedure for protection and reduction of infection transmission. Conclusion: The use of enhanced PPE, including PAPR, affected the performance of CPR to some extent but did not alter patient outcomes. PAPR use during the resuscitation of OHCA patients might positively impact the psychological stability of the medical staff. Full article

Since the beginning of the COVID-19 emergency, the referral Intensive Care Unit for the Extracorporeal Membrane Oxygenation (ECMO) support of Piedmont Region (Italy), in cooperation with infectious disease specialists, perfusionists and cardiac surgeons, developed a protocol to guarantee operator safety during invasive procedures, among which the ECMO positioning or inter-hospital transport. The use of powered air-purifying respirators, filtering facepiece particles (FFP) 2–3 masks, protective suits, disposable sterile surgical gowns, and two pairs of sterile gloves as a part of a protocol seemed effective and feasible for trained healthcare workers and allow all the complex activities connected with the positioning of the ECMO support to be completed effectively. The simulation training on donning and doffing procedures and the presence of a dedicated team member to verify the compliance with the safety procedure effectively reassured operators and likely reduced the risk of self-contamination. From 1 March to 31 December 2020, we used the procedure in 35 severe acute respiratory distress syndrome (ARDS) patients and one acute respiratory failure caused by neoplastic total tracheal obstruction, all positive to COVID-19, to be connected to veno-venous ECMO in peripheral hospitals and centralized for ECMO management. This preliminary experience seems to confirm that the use of ECMO during COVID-19 outbreaks is feasible and the risks associated with its positioning and management are sustainable for the health-care workers and safe for patients. Full article

Various types and levels of personal protective equipment (PPE) are currently available to protect health-care workers against infectious diseases. However, wearing cumbersome PPE may negatively affect their performance in life-saving procedures. This study aimed to evaluate the impact of wearing extensive PPE, including a powered air-purifying respirator with a loose-fitting hood or an N95 filtering facepiece respirator, on the first-pass success (FPS) rate of endotracheal intubation (ETI) in the emergency department (ED). This study was a single-center, observational before-and-after study of 934 adult (≥18 years old) patients who underwent ETI in the academic ED. The study period was divided into a control period (from 20 January 2019, to 30 September 2019, and from 20 January 2018, to 30 September 2018) and an intervention period (from 20 January 2020, to 30 September 2020). Extensive PPE was not donned during the control period (control group, n = 687) but was donned during the intervention period (PPE group, n = 247). The primary outcome was the FPS rate. We used propensity score matching between the PPE and control groups to reduce potential confounding. Propensity score matching identified 247 cases in the PPE group and 492 cases in the control group. In the matched cohort, no significant difference was found in the FPS rate between the PPE and control groups (83.8% (n = 207) vs. 81.9% (n = 403); p = 0.522). In multivariable analysis, wearing PPE was not associated with the FPS rate (adjusted odds ratio, 0.90; 95% confidence interval, 0.57–1.40; p = 0.629) after adjusting for the level of the intubator (junior resident, senior resident, or emergency medicine (EM) specialist). In conclusion, the FPS rate is not significantly affected by wearing extensive PPE in the ED. Full article