The usability of ventilator maintenance user interface: A comparative evaluation of user task performance, workload, and user experience

Poor usability designed of ventilator user interface can easily lead to human error. In this study, we evaluated the usability design of ventilator maintenance user interface and identified problems related to the usability of user interface that could easily cause human error. Sixteen respiratory therapists participated in this usability study. The usability of the ventilator maintenance user interface was evaluated by participants' task performance (task completion time, task error rate), physiological workload (eye-fixation duration) and perceived workload (NASA-TLX), and user experience (questionnaire). For task performance, task completion time and task error rate showed significant differences. For task completion time, significant difference was found when conducting ventilator self-test (p < 0.001), replace the breathing circuit (p = 0.047), and check battery status (p = 0.005). For task error rate, the three ventilators showed significant difference (p = 0.012), and the Serov I showed a significantly higher task error rate than the Boaray 5000D (p = 0.031). For workload, the Serov I was associated with higher physiological and perceived workloads than other ventilators (p < 0.05). For user experience, the Boaray 5000D received better scores among the ventilators in terms of ease to maintain, friendly to maintain, and willingness to use (p < 0.05, respectively). Our study adds available literature for usability evaluation of ventilator maintenance user interface. The results indicate that the maintenance user interface of the Boaray 5000D performed better than the other two tested ventilators. Moreover, the study results also proved that eye-fixation duration can be a reliable tool for evaluating the usability of ventilator user interface.

Patient-maintained propofol sedation for adult patients undergoing surgical or medical procedures: a scoping review of current evidence and technology

Patient-maintained propofol sedation (PMPS) is the delivery of procedural propofol sedation by target-controlled infusion with the patient exerting an element of control over their target-site propofol concentration. This scoping review aims to establish the extent and nature of current knowledge regarding PMPS from both a clinical and technological perspective, thereby identifying knowledge gaps to guide future research. We searched MEDLINE, EMBASE, and OpenGrey databases, identifying 17 clinical studies for analysis. PMPS is described in the context of healthy volunteers and in orthopaedic, general surgical, dental, and endoscopic clinical settings. All studies used modifications to existing commercially-available infusion devices to achieve prototype systems capable of PMPS. The current literature precludes rigorous generalisable conclusions regarding the safety or comparative clinical effectiveness of PMPS, however cautious acknowledgement of efficacy in specific clinical settings is appropriate. Based on the existing literature, together with new standardised outcome reporting recommendations for sedation research and frameworks designed to assess novel health technologies research, we have made recommendations for future pharmacological, clinical, behavioural, and health economic research on PMPS. We conclude that high-quality experimental clinical trials with relevant comparator groups assessing the impact of PMPS on standardised patient-orientated outcome measures are urgently required.

Breast and torso characteristics of female contact football players: implications for the design of sports bras and breast protection

This study aimed to provide normative data characterising the breast size, breast position and torso size of female contact football players. 117 AFL, Rugby League, Rugby Union and Rugby 7s players attended a single testing session where a three-dimensional scan was taken of their naked breasts and torso. Dimensions relevant to the design of sports bras and breast protective equipment were then calculated from the scans. Several breast and torso characteristics of female contact football athletes differed to measurements reported for females in the general population and amongst the contact football codes. Designers and manufacturers of sports bras or breast protective equipment should consider the specific breast and torso dimensions of female contact football players to maximise the fit, comfort and efficacy of these garments. Practitioner summary: Using three-dimensional scanning, this study characterised the breast and torso size and shape of 117 female contact football players. These normative data should be used to improve the fit and comfort of sports bras and breast protective equipment for female contact football players.

Robotic-Assisted Percutaneous Coronary Intervention Through Transradial Approach: Experience in 4 Patients with Complex Lesions

Robotic-assisted percutaneous coronary intervention can reduce the exposure of interventional cardiologists to radiation and minimize the risk of occupational orthopedic injuries from wearing heavy protective aprons. The PRECISE (Percutaneous Robotically-Enhanced Coronary Intervention) study showed the efficacy and safety of robotic-assisted procedures for relatively low-risk lesions in single coronary arteries. Several reports have described robotic-assisted treatment of complex high-risk lesions, mostly through the transfemoral approach. We report 4 cases of patients in whom we used the transradial approach to treat complex lesions in the left anterior descending coronary artery with bifurcation balloon angioplasty reconstruction (2 cases), in the ostium of the first diagonal branch, and in the right coronary artery.

Orbital Atherectomy and Heavily Calcified Saphenous Vein Graft Intervention

Percutaneous coronary intervention in the diseased saphenous vein graft differs significantly from that in the diseased native coronary artery. After being exposed to arterial pressures over time, vein grafts have substantially different plaque characteristics, with more inflammatory cells, more diffuse disease, and less calcification. Severe calcification of saphenous vein grafts, although uncommon, poses a high risk of stent underexpansion. Orbital atherectomy for treatment of de novo calcified coronary lesions has been associated with better outcomes at 5-year follow-up. However, there are no published data on the use of orbital atherectomy to treat severely calcified saphenous vein graft lesions. We present the case of a 77-year-old woman with non-ST-segment-elevation myocardial infarction who underwent successful orbital atherectomy to prepare a severely calcified saphenous vein graft lesion for stent implantation.

Oropharyngeal Oxygen Concentration Is Dependent on the Oxygen Mask System and Sampling Location

BACKGROUND

Numerous oxygen delivery systems are used to treat hypoxemia. It is unknown if F_IO2 at the lips predicts oropharyngeal F_IO2 for various oxygen mask systems. We tested whether F_IO2 measurements differed between the lips and oropharynx, and whether this difference depends on the mask system.

METHODS

Ten healthy volunteers had one sampling catheter positioned at the lips and another catheter in the oropharynx. F_IO2 was sampled at each location while the subjects breathed normal tidal volumes with oxygen at 15 L/min via 4 delivery devices: a simple mask, a non-rebreather mask, a face mask with a diffuser that concentrates and directs O₂ toward the mouth and nose (mask with diffuser), and a closed mask with a Jackson-Rees circuit. Data were analyzed by using a linear mixed model to account for subject crossover in the repeated measures design.

RESULTS

F_IO2 levels differed significantly for the 4 delivery mask systems (P < .001) and by sampling catheter location (P < .001). Differences in mean F_IO2 between the lips and the oropharynx were observed for the mask with diffuser (difference 0.30, 95% CI 0.25-0.36; P < .001), and non-rebreather mask (difference 0.09, 95% CI 0.04-0.15; P = .001). The mean F_IO2 at the oropharynx was highest for the closed mask (0.97, 95% CI 0.92-1.00), followed by the non-rebreather mask (0.76, 95% CI 0.72-0.81), simple mask (0.62, 95% CI 0.58-0.67), and the mask with diffuser (0.51, 95% CI 0.46-0.56). At the lips, the mean F_IO2 was highest for the closed mask (0.97, 95% CI 0.92-1.00), followed by the non-rebreather mask (0.86, 95% CI 0.81- 0.90), OxyMask (0.81, 95% CI 0.76-0.86), and simple mask (0.67, 95% CI 0.62-0.71).

CONCLUSIONS

With high oxygen flows and normal tidal volume breathing, F_IO2 measurements obtained at the oropharynx or at the lips depended on the device used, with the mask with diffuser showing the most significant discrepancies. F_IO2 measures at the oropharynx and the lips were only consistent for the closed mask system. (ClinicalTrials.gov registration NCT02523586.).

Development of Treatments for Localized Prostate Cancer in Patients Eligible for Active Surveillance: U.S. Food and Drug Administration Oncology Center of Excellence Public Workshop

PURPOSE

The following is a summary of discussion at a United States FDA (Food and Drug Administration) public workshop reviewing potential trial designs and end points to develop therapies to treat localized prostate cancer.

MATERIALS AND METHODS

The workshop focused on the challenge that drug and device development to treat localized prostate cancer has been limited by the large trial sizes and lengthy timelines required to demonstrate an improvement in overall or metastasis-free survival and by the lack of agreed on alternative end points. Additionally, evolving treatment paradigms in the management of localized prostate cancer include the widespread use of active surveillance of patients with low and some intermediate risk prostate cancer, and the availability of advances in imaging and genomics.

RESULTS

The workshop addressed issues related to trial design in this setting. Attendees discussed several potential novel end points such as a delay of morbidity due to radiation or prostatectomy and pathological end points such as Gleason Grade Group upgrade.

CONCLUSIONS

The workshop provided an open forum for multiple stakeholder engagement to advance the development of effective treatment options for men with localized prostate cancer.

Minimally Invasive Endovascular Repair of Ascending Thoracic Aortic Aneurysm with Use of Local Anesthesia and Conscious Sedation

Ascending thoracic aortic aneurysm (ATAA) is typically treated surgically. No commercially available device has been specifically designed for endovascular ATAA repair, and currently, multiple anatomic and technical challenges affect its feasibility. Previously, such repairs have been performed with the patients under general anesthesia. We describe a novel, minimally invasive approach to endovascular repair of ATAA, involving local anesthesia, conscious sedation, and 24-hour hospitalization. Two consecutive male patients (ages, 79 and 54 yr) who had comorbidities underwent percutaneous transfemoral endovascular ATAA repair with use of commercially available endografts. Patient 1 had a saccular aneurysm, and Patient 2 had a pseudoaneurysm consequent to recent surgical ATAA repair. The patients were discharged from the hospital 24 hours after technically successful, uncomplicated procedures. At 2 months, computed tomograms showed no endoleak or stent-graft migration. Our experience shows that minimally invasive endovascular ATAA repair is feasible for selected high-risk patients. We describe the procedure, access and closure devices, and challenges associated with this approach.

Effect of Percutaneous Suction Thromboembolectomy on Improved Right Ventricular Function

Venous thromboembolism is a leading cause of cardiovascular death. Historically, surgical intervention has been associated with high morbidity rates. Pharmacologic therapy alone can be inadequate for patients with substantial hemodynamic compromise, so minimally invasive procedures are being developed to reduce clot burden. We describe our initial experience with using the AngioVac system to remove thromboemboli percutaneously. We reviewed all suction thromboembolectomy procedures performed at our institution from March 2013 through August 2015. The main indications for the procedure were failed catheter-directed therapy, contraindication to thrombolysis, bleeding-related complications, and clot-in-transit phenomena. We collected details on patient characteristics, procedural indications, thrombus location, hemodynamic values, cardiac function, pharmacologic support, and survival to discharge from the hospital. The Wilcoxon signed-rank test was used for statistical analysis. Thirteen patients (mean age, 56 ± 15 yr; 10 men) underwent suction thromboembolectomy; 10 (77%) survived to hospital discharge. The median follow-up time was 74 days (interquartile range [IQR], 23-221 d). Preprocedurally, 8 patients (62%) had severe right ventricular dysfunction; afterwards, 11 (85%) had normal function or mild-to-moderate dysfunction, and only 2 (17%) had severe dysfunction (P=0.031). Percutaneous suction thromboembolectomy, a promising therapeutic option for patients, appears to be safe, and we found it to be associated with improved right ventricular function.

Methodology and feasibility of a 3D printed assistive technology intervention

Three-dimensional (3D) printing now allows rehabilitation professionals to design and manufacture assistive technologies in a few hours. However, there is limited guidance for researchers and clinicians for implementing 3D printing assistive technology interventions and measuring their outcomes. The goal of this study was to develop a standardized 3D printing assistive technology intervention and a research methodology, using pillboxes as an example. Fourteen pillbox users engaged in a study comparing their use of an off-the-shelf pillbox to a customized 3D printed pillbox. Study outcomes were evaluated on feasibility (recruitment capability, study procedures and outcome measures, acceptability of the study procedures, the research team's ability to manage and implement the study, and the participant's preliminary response to intervention). Participant outcomes were measured on satisfaction with the device and medication adherence. Fourteen participants completed the study and received customized 3D printed pillboxes. The study design performed well on all aspects of feasibility except the research team's ability to manage and implement the study, as they experienced several technical issues. Notably, the participants reported improved device satisfaction and medication adherence with the 3D printed device with large effect sizes. The 3D printed assistive technology intervention is a replicable process that supports professionals in printing their own assistive technologies. Recommendations are made to further enhance feasibility of 3D printing assistive technology studies. Future research is warranted.IMPLICATIONS FOR REHABILITATION3D printing is an increasingly feasible approach allowing for the design and manufacture of customized assistive technologyEvaluation for assistive technology that will be 3D printed should include information about the person's activities, routines, skills, abilities, and preferences. Evaluation of outcomes should include satisfaction with the device and a functional measure.3D printed assistive technology interventions should include the collaboration between the assistive technology professional and client. It should also include device training.Future 3D printing research studies should report pragmatic data including printing device, time to print, and number of errors.

A Usability Study of 3 Radiotherapy Systems: A Comparative Evaluation Based on Expert Evaluation and User Experience

BACKGROUND The complex user interface design of radiotherapy treatment delivery systems can lead to use error and patient harm. In this study, we present the results of a comparison of 3 radiotherapy treatment delivery systems now used in China. MATERIAL AND METHODS We conducted a comprehensive usability study of 3 radiotherapy treatment delivery systems. Expert evaluation was performed through heuristic evaluation with 3 human-factors experts and 1 experienced radiation therapist for each system. User experience was assessed through perceived system usability and workload, using the National Aeronautics and Space Administration Task Load Index and the Post-Study System Usability Questionnaire. RESULTS For the expert evaluation, 47 usability problems were identified for Varian Trilogy, 75 for Elekta Precise, and 37 for Shinva XHA600E. Most problems were classified as major and minor usability problems, and were found in the process of patient setup and setup verification. For the user experience, radiation therapists presented a lower workload for Varian Trilogy compared to Elekta Precise (P<0.01) and Shinva XHA600E (P<0.01), and a lower workload for Elekta Precise compared to Shinva XHA600E (P=0.020). Radiation therapists perceived a higher system usability for Varian Trilogy compared to Shinva XHA600E (P<0.01), and a higher system usability for Elekta Precise compared to Shinva XHA600E (P<0.01). CONCLUSIONS This research provides valuable data on how 3 radiotherapy treatment delivery systems compare. The results of this study may be useful for hospital equipment procurement decisions, and designing next-generation products to improve patient safety.

A Tablet-Based Interactive Movement Tool for Pediatric Rehabilitation: Development and Preliminary Usability Evaluation

BACKGROUND

Motivating interactive tools may increase adherence to repetitive practice for children with disabilities, but many virtual reality and active video gaming systems are too challenging for children with significant needs.

OBJECTIVE

The objective of this study was to develop and conduct a usability evaluation of the Fun, Interactive Therapy Board (FITBoard), a movement toy bridging digital and physical interactions for children with disabilities.

METHODS

The FITBoard is a tablet app involving games controlled by hand, head, or foot touch of configurable, wired surfaces. Usability evaluation involved a cognitive walkthrough and think-aloud processes. Participants verbalized aloud while completing a series of 26 task actions involved in selecting a game and configuring the FITBoard to achieve the therapeutic goal. Therapists then responded to questions about usability perceptions. Unsuccessful actions were categorized as goal or action failures. Qualitative content analysis supported understanding of usability problems.

RESULTS

Participants included 5 pediatric physical therapists and 2 occupational therapists from 2 clinical sites. Goal failure was experienced by all participants in 2 tasks, and action failure was experienced by all participants in 2 tasks. For 14 additional tasks, 1 or more patients experienced goal or action failure, with an overall failure rate of 69% (18 of 26 tasks). Content analysis revealed 4 main categories: hardware usability, software usability, facilitators of therapy goals, and improvement suggestions.

CONCLUSIONS

FITBoard hardware and software changes are needed to address goal and action failures to rectify identified usability issues. Results highlight potential FITBoard applications to address therapeutic goals and outline important practical considerations for product use by therapists. Subsequent research will evaluate therapist, parent, and child perspectives on FITBoard clinical utility when integrated within regular therapy interventions.

An Experience of Improvised Laryngoscopy

Airway management in the wilderness runs the gamut from basic airway support to endotracheal intubation. Fortunately, direct laryngoscopy is a seldom called upon skill in expedition medicine. However, the medical skills required during a mission or expedition are never truly known in advance. Improvisation during evolving medical events is a mainstay of expedition medicine education and practice. It is unlikely, given constraints of weight and size of expedition medical kits, that a conventional laryngoscope would find its way into a standard "go bag." Faced with the real but rare event of needing to intubate a patient in an austere environment, how can improvisation be used? Multiple ideas for improvised laryngoscopes can be found in the wilderness medicine literature, but which, if any, of these devices have true clinical utility? To this end, participants of a recent Wilderness Medical Society preconference in medical elements of light search and rescue were given the opportunity to devise and construct their own improvised laryngoscopes and attempt intubation of a training mannequin. Participants with varying degrees of intubating experience improvised effective laryngoscopes from provided materials and successfully intubated an airway mannequin.

Impella RP Support and Catheter-Directed Thrombolysis to Treat Right Ventricular Failure Caused by Pulmonary Embolism in 2 Patients

Right ventricular failure secondary to pulmonary embolism is associated with morbidity and death. The Impella RP System has often been used for percutaneous mechanical circulatory support in patients with right ventricular failure from other causes, including myocardial infarction, cardiac surgery, and left ventricular assist device implantation. We report 2 cases of massive pulmonary embolism in which combined Impella RP use and ultrasound-assisted catheter-directed thrombolysis effectively treated shock caused by right ventricular failure and contributed to successful outcomes. To our knowledge, only one other patient with this indication had been treated with the Impella RP device.

Long-Term Continuous-Flow Biventricular Support in a 63-Year-Old Woman

We describe the successful use of long-term biventricular continuous-flow mechanical circulatory support as a bridge to transplantation in a small-framed 63-year-old woman with long-standing nonischemic cardiomyopathy. After placement of a left-sided HeartWare HVAD, persistent right-sided heart failure necessitated implantation of a second HeartWare device for long-term right ventricular support. After 262 days, the patient underwent successful orthotopic heart transplantation and was discharged from the hospital. This report indicates the feasibility of biventricular device support in older patients of relatively small stature, and our results may encourage others to consider this therapy in similar patient populations.

New Pulmonary Valvuloplasty Technique by Use of an Hourglass-Shaped Balloon in 3 Adults with Severe Pulmonary Valve Stenosis

Percutaneous balloon pulmonary valvuloplasty is the preferred therapy for pulmonary valve stenosis. However, the designs of the cylindrical balloons historically used for valvuloplasty have limitations, especially in patients who have large pulmonary annular diameters. The hourglass-shaped V8 Aortic Valvuloplasty Balloon may prove to be an effective alternative. The balloon has 2 large bulbous segments that are separated by a narrowed waist. The geometric shape is maintained throughout inflation, improving fixation and enabling broader leaflet opening. We present our first experience with the V8 balloon in 3 adults who had severe, symptomatic pulmonary valve stenosis. In addition to describing their cases, we detail our sizing technique for pulmonary valvuloplasty with the V8 balloon. Our successful results suggest that the V8 balloon is efficient and safe for balloon pulmonary valvuloplasty in adults with severe pulmonary valve stenosis.

Distances from vocal cords to mid-trachea for optimizing endotracheal tubes depth markers according to gestational age

BACKGROUND

Adequate endotracheal tube positioning in preterm infants is complicated by the short length of the airway. Distal markers were designed to help with the insertion of endotracheal tubes at an appropriate depth below the vocal cords. However, those markers are not standardized between manufacturers, each tube size displays only one (sometimes 2) markers to provide information for infants of various gestational ages, and indicated distances are often too long for extremely preterm infants.

AIMS

The study aims to describe vocal cords to mid-tracheal distance for different gestational ages and determine if depth markers should be adjusted accordingly.

METHODS

Half the tracheal length added to the height of the posterior lamina of the cricoids approximates the distance between vocal cords and mid-trachea. Those dimensions were retrospectively retrieved from a database of laryngo-tracheal measurements obtained during autopsies of fetuses and newborn infants free of upper airway malformations. The equation of correlation between gestational age and distance from vocal cords to mid-trachea was used to calculate those distances for different gestational ages.

RESULTS

Data were derived from 114 patients. Vocal cords to mid-trachea distance is linearly correlated with gestational age (r = .90; distance = 2.831 + 0.6208 × gestational age). We suggest depth markers at 17.7, 19.0, 20.8, 22.7, 24.6, and 26.4 mm for gestational ages of 24, 26, 29, 32, 35, and 38 weeks, respectively, indicated by contrasting colors.

CONCLUSION

The linear relationship between laryngo-tracheal size and gestational age offers the opportunity to revise endotracheal tube depth markers for the smallest patients. Trials comparing those suggested markers with those currently in use are needed before implementation.

Adapting the Wii Fit Balance Board to Enable Active Video Game Play by Wheelchair Users: User-Centered Design and Usability Evaluation

Background

Active video game (AVG) playing, also known as “exergaming,” is increasingly employed to promote physical activity across all age groups. The Wii Fit Balance Board is a popular gaming controller for AVGs and is used in a variety of settings. However, the commercial off-the-shelf (OTS) design poses several limitations. It is inaccessible to wheelchair users, does not support the use of stabilization assistive devices, and requires the ability to shift the center of balance (COB) in all directions to fully engage in game play.

Objective

The aim of this study was to design an adapted version of the Wii Fit Balance Board to overcome the identified limitations and to evaluate the usability of the newly designed adapted Wii Fit Balance Board in persons with mobility impairments.

Methods

In a previous study, 16 participants tried the OTS version of the Wii Fit Balance Board. On the basis of observed limitations, a team of engineers developed and adapted the design of the Wii Fit Balance Board, which was then subjected to multiple iterations of user feedback and design tweaks. On design completion, we recruited a new pool of participants with mobility impairments for a larger study. During their first visit, we assessed lower-extremity function using selected mobility tasks from the International Classification of Functioning, Disability and Health. During a subsequent session, participants played 2 sets of games on both the OTS and adapted versions of the Wii Fit Balance Board. Order of controller version played first was randomized. After participants played each version, we administered the System Usability Scale (SUS) to examine the participants’ perceived usability.

Results

The adapted version of the Wii Fit Balance Board resulting from the user-centered design approach met the needs of a variety of users. The adapted controller (1) allowed manual wheelchair users to engage in game play, which was previously not possible; (2) included Americans with Disabilities Act-compliant handrails as part of the controller, enabling stable and safe game play; and (3) included a sensitivity control feature, allowing users to fine-tune the controller to match the users’ range of COB motion. More than half the sample could not use the OTS version of the Wii Fit Balance Board, while all participants were able to use the adapted version. All participants rated the adapted Wii Fit Balance Board at a minimum as “good,” while those who could not use the OTS Wii Fit Balance Board rated the adapted Wii Fit Balance Board as “excellent.” We found a significant negative correlation between lower-extremity function and differences between OTS and adapted SUS scores, indicating that as lower-extremity function decreased, participants perceived the adapted Wii Fit Balance Board as more usable.

Conclusions

This study demonstrated a successful adaptation of a widely used AVG controller. The adapted controller’s potential to increase physical activity levels among people with mobility impairments will be evaluated in a subsequent trial.

Trial Registration

ClinicalTrials.gov NCT02994199; https://clinicaltrials.gov/ct2/show/NCT02994199 (Archived by WebCite at http://www.webcitation.org/6xWTyiJWf)

Loss of Surfacten® during bolus administration with a feeding catheter

BACKGROUND

Surfactant replacement therapy is widely used for treating neonatal respiratory distress syndrome, but insufficient evidence is available on the use of Surfacten® (S-TA). This study investigated the inadvertent loss of S-TA during instillation via feeding catheters with different bore sizes.

METHODS

In this bench-based study, we measured the weight of syringes and tubes before and after surfactant treatment using a high-accuracy balance, and determined the amount of S-TA lost in tubes. We injected 120 mg of S-TA suspended in 4 or 3 mL into tubes followed with or without air boluses. Experiments were performed in triplicate. Percent weight loss of S-TA in each tube was calculated with or without air boluses.

RESULTS

Percent weight loss of S-TA was significantly higher in larger-bore tubes (P < 0.01, overall ANOVA), and was significantly lower after air bolus flushing in 3 Fr, 4 Fr, and 5 Fr tubes (P < 0.005, respectively). The 3 mL S-TA suspensions had a significantly higher percent loss than the 4 mL S-TA suspensions when using 4 Fr and 5 Fr tubes, and the 5 Fr closed system (P < 0.05, respectively).

CONCLUSIONS

Routine air bolus flushing effectively reduces S-TA loss in tubes. The 3 mL S-TA suspensions appear to be more susceptible to inadvertent S-TA loss during instillation. Therefore, caution is warranted for this procedure.

Performance of the New Turbine Mid-Level Critical Care Ventilators

BACKGROUND

During recent years, ventilators using turbines as flow-generating systems have become increasingly more relevant. This bench study was designed to compare triggering and pressurization of 7 turbine mid-level ICU ventilators.

METHODS

We used a dual-chamber lung model to test 7 mid-level ICU ventilators in pressure support mode with levels of 10, 15, and 20 cm H₂O with 2 PEEP levels of 5 cm H₂O and the minimum level allowed by the ventilator. A ventilator was connected to the master chamber to simulate 2 different effort levels. Pressure drop, trigger delay time, time to minimum pressure, and pressure time products (PTP) during trigger and the first 300 and 500 ms were analyzed.

RESULTS

In the trigger evaluation, the Savina had the highest delay time, whereas the C2, the V60, and the Trilogy had the lowest pressure drops and PTP values in both effort levels. In pressurization capacity assessment using ideal PTP300 and PTP500 percentages, the C2 and the V680 had the best results, and the Carina and the Savina had lower values, with no differences between both effort levels. Differences between PEEP levels did not seem to be relevant.

CONCLUSIONS

Pressure support mode for tested ventilators worked properly, but pressurization capacity and trigger function performance were clearly superior in the newest machines. The use of PEEP did not modify the results.

Full-shift and task-specific upper extremity muscle activity among US large-herd dairy parlour workers

US large-herd dairy parlour workers experience a high prevalence of musculoskeletal symptoms in the upper extremity. The purpose of this study was to estimate and compare full-shift and task-specific muscle activity of the upper extremity among parlour workers. Surface electromyography data were recorded continuously throughout a full work shift for each participant (n = 60). For a subset of participants (n = 33), muscular effort was estimated for milking task cycles. Lower muscle activity levels and higher per cent muscular rest was observed among rotary parlour participants as compared to herringbone and parallel parlour participants for anterior deltoid, forearm flexor and forearm extensor muscles. These findings suggest rotary parlours may offer workstation designs or work organisational dynamics which may be more beneficial to the health and performance of the worker, as compared to parallel or herringbone parlours. Practitioner Summary: Study findings suggest milking parlour configurations present different biomechanical demands on workers which may influence worker health and performance. Our findings will enable more informed decisions regarding both engineering (e.g. parlour configuration or milking equipment) and administrative (e.g. work organisation) control strategies for large-herd milking parlours.

A Prospective Case-Control Study Comparing LithoVue, a Single-Use, Flexible Disposable Ureteroscope, with Flexible, Reusable Fiber-Optic Ureteroscopes

OBJECTIVE

LithoVue™ is a novel, single-use, digital flexible ureteroscope that was released to the US market in January 2016. There are scant data regarding its performance in humans. Procedural outcomes comparing LithoVue with reusable ureteroscopes are presented in patients undergoing ureteroscopy for upper urinary tract pathology.

PATIENTS AND METHODS

Clinical outcomes between two groups of patients undergoing flexible ureteroscopy for upper urinary tract pathology were analyzed. The first group underwent surgery utilizing LithoVue, and the second group used reusable fiber-optic flexible ureteroscopes. Differences in procedural outcomes, operative times, and time spent in hospital were analyzed using two-tailed t-tests and chi-squared and Fisher's exact tests.

RESULTS

One hundred fifteen cases utilizing LithoVue and 65 cases utilizing reusable ureteroscopes were included in this study. Demographics, surgical indications, stone size, location, total stone burden, composition, procedural outcomes, and complications were comparable between groups. For all cases, LithoVue procedures lasted 54.1 ± 25.7 minutes compared with 64.5 ± 37.0 minutes for reusable scope procedures (p < 0.05) and for stone removal cases, 57.3 ± 25.1 vs 70.3 ± 36.9 minutes, respectively (p < 0.05). Scope failure occurred in 4.4% of LithoVue cases and 7.7% of reusable cases (p = 0.27).

CONCLUSIONS

LithoVue represents a feasible alternative to reusable ureteroscopes with a low rate of scope failure comparable with reusable ureteroscopes. Its use shortens procedure duration, a finding that warrants further investigation.

Titanium Plug Closure after HeartWare Ventricular Assist Device Explantation in a 15-Year-Old Girl: First U.S. Experience

We describe the case of a teenage girl with anthracycline-induced cardiomyopathy who received a HeartWare ventricular assist device and underwent successful device explantation after cardiac recovery. During device support, the patient's cardiac function returned to normal. Twelve months after implantation, we explanted the device via repeat median sternotomy. To close the hole in the left ventricular apex and preserve the sewing ring in case future device support is needed, we used a German-manufactured titanium plug, developed specifically for this purpose. To our knowledge, this is the first use of this plug in the United States. The patient recovered uneventfully and was discharged from the hospital on postoperative day 11. Left ventricular biopsy specimens at explantation revealed the resolution of previous degenerative sarcomeric changes. Our patient did well clinically; however, recurrent late anthracycline cardiotoxicity might subsequently cause her cardiac function to deteriorate. In this event, our use of the titanium plug to preserve the left ventricular sewing ring would enable easier device replacement than would other explantation options.

Drop-off detection with the long cane: effect of cane shaft weight and rigidity on performance

Most travellers who are blind rely on a long cane to detect drop-offs on their walking paths. We examined how different cane shaft materials affect drop-off detection performance through providing different vibrotactile and proprioceptive feedbacks to the cane user. Results of the study showed a significant interaction between cane shaft weight and how the cane is used. A heavier cane was advantageous for detecting drop-offs when the individual used the 'constant contact technique' - cane tip stays in contact with the walking surface at all times - but not when he used the 'two-point touch technique' - cane tip is rhythmically tapped on the surface. In addition, a more flexible cane was advantageous for detecting drop-offs when the two-point touch technique was used but not when the constant contact technique was used. It is recommended that, when blind individuals select a cane shaft material, they consider which long cane technique they use more often. Practitioner Summary: Long cane shaft material affects how well a blind individual can detect drop-offs. A heavier shaft was advantageous when using the constant contact technique (cane tip stays in continuous contact with the surface), while a more flexible shaft was better when using the two-point touch technique (cane tip rhythmically taps the surface).

Development and Application of a Clinical Microsystem Simulation Methodology for Human Factors-Based Research of Alarm Fatigue

OBJECTIVES

(1) To develop a clinical microsystem simulation methodology for alarm fatigue research with a human factors engineering (HFE) assessment framework and (2) to explore its application to the comparative examination of different approaches to patient monitoring and provider notification.

BACKGROUND

Problems with the design, implementation, and real-world use of patient monitoring systems result in alarm fatigue. A multidisciplinary team is developing an open-source tool kit to promote bedside informatics research and mitigate alarm fatigue.

METHOD

Simulation, HFE, and computer science experts created a novel simulation methodology to study alarm fatigue. Featuring multiple interconnected simulated patient scenarios with scripted timeline, "distractor" patient care tasks, and triggered true and false alarms, the methodology incorporated objective metrics to assess provider and system performance. Developed materials were implemented during institutional review board-approved study sessions that assessed and compared an experimental multiparametric alerting system with a standard monitor telemetry system for subject response, use characteristics, and end-user feedback.

RESULTS

A four-patient simulation setup featuring objective metrics for participant task-related performance and response to alarms was developed along with accompanying structured HFE assessment (questionnaire and interview) for monitor systems use testing. Two pilot and four study sessions with individual nurse subjects elicited true alarm and false alarm responses (including diversion from assigned tasks) as well as nonresponses to true alarms. In-simulation observation and subject questionnaires were used to test the experimental system's approach to suppressing false alarms and alerting providers.

CONCLUSIONS

A novel investigative methodology applied simulation and HFE techniques to replicate and study alarm fatigue in controlled settings for systems assessment and experimental research purposes.