Syringe Driver Research Articles

Role of Coriolis flow measurement technology in validation of model of syringe driver performance

The development of a flow/pressure measurement system in association with Bronkhorst High-Tech B.V. incorporating a Coriolis flow transducer, provided an opportunity to observe the flow/pressure dynamics of syringe drivers. A model of flow/pressure performance of syringe drivers was established where key variable factors included the compliance of the connected system and the associated line resistance. It was identified that the flow/pressure dynamics observed with the flow measurement system incorporating the Coriolis transducer matched that of the model. In this consideration the dominant compliance contribution related to that of the syringe. The model operates by considering the notional volume change in the residual fluid volume in the syringe with inflow from stepper motor action and outflow in the interval between sequential pulses. While many of the observations in the literature of syringe driver function are qualitative, the model allows a more precise prediction of associated device performance.

Toward Onboard Proportional Control of Multi-Chamber Soft Pneumatic Robots: A Magnetorheological Elastomer Valve Array.

Soft pneumatic actuators (SPAs) are commonly used in various applications because of their structural compliance, low cost, ease of manufacture, high adaptability, and safe human-robot interaction. The traditional approach for achieving proportional control of soft pneumatic robots requires the use of industrial proportional valves or syringe drivers, which are not only rigid and bulky but also hard to be integrated into the body of soft robots. In our previous research, we developed a Magnetorheological elastomer (MRE)-based soft valve that showed advantages for controlling SPAs due to its compliance, compactness, robustness, and compatibility for continuous pressure modulation. Modern soft robots with multiple chambers require more MRE valves onboard for their control. However, merely packing more MRE valves for soft robots can cause problems like magnetic interference, flow rate deviation, and overheating. Therefore, in this study, we proposed a two-dimensional MRE valve array design to solve issues of magnetic interference and overheating when expanding from a single MRE proportional valve into an integrated array. The magnetic interference and the overheating problem were investigated through multiphysics simulation, bringing the optimal choice of valve spacing (1.2 times the single valve diameter), magnetic coil pole arrangement (same pole), and the cooling system design (internal cooling chamber with flowing water). Physical experiments showed that our MRE valve array maintained its original flowrate performance with low magnetic interference (0.89 mT) and low coil temperature (under 73.9°C for 5 min).

The Investigation of Bio-impedance Analysis at a Wrist Phantom with Two Pulsatile Arteries.

Bio-impedance analysis (BIA) has been widely investigated for hemodynamic monitoring. However, previous works rarely modelled two synchronously pulsatile arteries (representing the radial and ulnar arteries) in the wrist/forearm model. This work aims to clarify and quantify the influences of two pulsatile arteries on BIA. First, two blood-filled arteries were structured in a 3D wrist segment using the finite element method (FEM). Afterwards, an easy-to-produce two-arteries artificial wrist was fabricated with two components: gelatine-based surrounding tissue phantom and saline blood phantom. A syringe driver was utilised to constrict the arteries, and the impedance signals were measured using a Multi-frequency Impedance Analyser (MFIA). Both simulation and experimental results demonstrated the non-negligible influences of the ulnar artery on the overall BIA, inducing unwanted resistance changes to the acquired signals from the radial artery. The phantom experiments revealed the summation of the individual resistance changes caused by a single pulsatile artery was approximately equal to the measured resistance change caused by two synchronously pulsatile arteries, confirming the measured impedance signal at the wrist contains the pulsatile information from both arteries. This work is the first simulation and phantom investigation into two synchronously pulsatile arteries under BIA in the distal forearm, providing a better insight and understanding in the morphology of measured impedance signals. Future research can accordingly select either a small spacing 4-spot electrode configuration for a single artery sensing or a band electrode configuration for overall pulsatile arteries sensing. A more accurate estimation of blood volume change and pulse wave analysis (PWA) could help to develop cuffless blood pressure measurement (BPM).

A Reliable Production System of Large Quantities of [13N]Ammonia for Multiple Human Injections.

[13N]Ammonia is one of the most commonly used Positron Emission Tomography (PET) radiotracers in humans to assess myocardial perfusion and measure myocardial blood flow. Here, we report a reliable semi-automated process to manufacture large quantities of [13N]ammonia in high purity by proton-irradiation of a 10 mM aqueous ethanol solution using an in-target process under aseptic conditions. Our simplified production system is based on two syringe driver units and an in-line anion-exchange purification for up to three consecutive productions of ~30 GBq (~800 mCi) (radiochemical yield = 69 ± 3% n.d.c) per day. The total manufacturing time, including purification, sterile filtration, reformulation, and quality control (QC) analyses performed before batch release, is approximately 11 min from the End of Bombardment (EOB). The drug product complies with FDA/USP specifications and is supplied in a multidose vial allowing for two doses per patient, two patients per batch (4 doses/batch) on two separate PET scanners simultaneously. After four years of use, this production system has proved to be easy to operate and maintain at low costs. Over the last four years, more than 1000 patients have been imaged using this simplified procedure, demonstrating its reliability for the routine production of large quantities of current Good Manufacturing Practices (cGMP)-compliant [13N]ammonia for human use.

10 clinical tips for advancing patient safety when using syringe pump systems for microinfusion intravenous drug therapy.

10 clinical tips for advancing patient safety when using syringe pump systems for microinfusion intravenous drug therapy.

Molecular Epidemiological Investigation and Management of Outbreak Caused by Carbapenem-Resistant Acinetobacter baumannii in a Neonatal Intensive Care Unit.

The present study describes an epidemiological investigation into a carbapenem-resistant Acinetobacter baumannii (CRAB) outbreak, which had occurred in a neonatal intensive care unit (NICU), and the subsequent strengthening of infection control interventions. Upon the onset of the outbreak, existing infection control interventions were reviewed, and a set of containment measures were instituted. All CRAB isolates were characterized in terms of antimicrobial susceptibility testing and their genetic relatedness. The investigation process identified gaps within the NICU's existing infection control measures, which had likely resulted in the outbreak. CRAB was isolated from nine preterm infants: five colonized and four infected. All five colonized patients were discharged well. However, three out of four of the infected infants died. Outbreak investigation and genomic subtyping of environmental swabs revealed that mini syringe drivers shared between patients and a sink in the milk preparation room had served as CRAB reservoirs with possible transmission via the hands of healthcare workers. Implementation of immediate actions such as reinforcement of hand hygiene practices, intensified environmental cleaning, geographical cohorting, reviewing of milk handling practices and sink management protocol had resulted in no further CRAB isolation. The CRAB outbreak in the NICU underlines the importance of consistent compliance with infection-control interventions. Integration of epidemiological and microbiological data, together with comprehensive preventive measures, successfully brought the outbreak to a halt.

The effect of body condition on alfaxalone induction dosage requirement in dogs.

Alfaxalone is commonly used in veterinary anesthesia for the induction of general anesthesia (GA) in dogs. However, it has been associated with dose-dependent cardiovascular depression. Therefore, the administration of liposoluble, intravenous (IV)-administered injectable induction agents, such as alfaxalone, is recommended to be based on the dog's lean body mass (LBM). To determine the influence of body condition score (BCS) on IV alfaxalone dose requirements to achieve endotracheal intubation in dogs. Prospective clinical study. A group of 34 dogs undergoing GA for diagnostic and/or surgical procedures, body weight (BW) > 4 kg, BCS > 2, age 1-14 years, American Society of Anesthesiologists (ASAs) classification I-III. Dogs were allocated to two different groups according to their BCS: non-overweight group (NOW) BCS: 3-5 and over-weight group (OW) BCS: 6-9. All dogs were premedicated IV with methadone 0.2 mg kg-1, and anesthesia was induced by a slow IV infusion of alfaxalone at 1 mg kg-1 minute-1, delivered with a syringe driver, until loss of jaw tone and no/minimal gagging reflex sufficient to allow endotracheal intubation was achieved. The total dose of alfaxalone and the occurrence of post-induction apnoea were recorded.The Shapiro-Wilk test was performed to test for normality. A Chi-square test was performed to compare the incidence of post-induction apnoea between groups, and the Mann-Whitney U test was performed to compare the induction dose of alfaxalone between groups. A p-value < 0.05 was considered statistically significant. The mean dose ± standard deviation of alfaxalone in NOW was 2.18 ± 0.59 mg kg-1, and in OW, it was 1.63 ± 0.26 mg kg-1 (p = 0.002). The sedation score did not differ between groups. Postinduction apnoea (PIA) occurred in 6 of 17 animals in NOW and 15 of 17 in OW (p = 0.002). The dose of IV alfaxalone per kg of total body mass required to achieve endotracheal intubation was lower in overweight dogs, suggesting that LBM should be considered when calculating IV anesthetic doses. The incidence of post-induction apnoea was higher in overweight/obese dogs with alfaxalone administered at a rate of 1 mg kg-1 minute-1.

PP344 [Resuscitation, Stabilisation &amp; Transport » Critical care response teams (rapid response teams)]: THE EFFECT OF SYRINGE DRIVER ORIENTATION AND DISPLACEMENT ON DELIVERY VARIABILITY UNDER G-FORCE STRESS

1University of Nottingham School of Medicine, Nottingham, UK 2Paediatric Critical Care Unit, Nottingham Children’s Hospital, Nottingham UK 3Pharmacy Department, Nottingham Children’s Hospital, Nottingham UK

Hospital Specialist Palliative Care Team Influence on End-of-Life Care in Coronavirus Disease 2019? A Retrospective Observational Cohort Study.

The coronavirus 19 disease (COVID-19) pandemic has led to a renewed focus on end-of-life care. The majority of COVID-19 deaths occur in hospital, with patients cared for by generalists and hospital specialist palliative care teams (HSPCTs). This project aims at exploring the potential influences of HSPCTs on end-of-life care in COVID-19. A retrospective observational study was carried out by exploring four end-of-life care themes in a Scottish hospital population who died from COVID-19. Comparison was made between cohorts seen by HSPCTs versus generalist clinicians. Analysis of 119 patients across NHS Greater Glasgow and Clyde (NHSGGC) health board demonstrated that COVID-19 patients seen by HSPCTs were more likely to be younger (median 77 vs. 81 years; p = 0.02), have a cancer diagnosis (21.7% vs. 5.4%; p = 0.01), die sooner after admission (median four vs. six days; p < 0.01), and be commenced on a syringe driver (89.1% vs. 42.5%; p < 0.01). Differences detected across four end-of-life care themes comparing HSPCTs with generalist teams were minimal with documentation and prescribing in keeping with available guidance. Consistencies in end-of-life care observed across NHSGGC cohorts draw attention to the potential wider impact of HSPCT roles, including education, guideline development, and mentoring. Understanding such diverse effects is important to support funding and development of HSPCTs. Further research is required to better quantify the impact and heterogenous influences of HSPCTs in general.

Management of end stage sCJD from a palliative care perspective

Sporadic Creutzfeldt-Jakob Disease (sCJD) is a rare, rapidly progressive neurological disorder, that is ultimately fatal. We have written a case report on a patient recently admitted to the hospice having been diagnosed 2 days earlier with sCJD. Unfortunately, she had an aggressive form and deteriorated very rapidly 10 days post admission. Our focus was on symptom control and supportive care, for both patient and family, with psychological and spiritual support a vital component of this. Of her multitude of symptoms, the most challenging were the fluctuating episodes of severe emotional distress, agitation and restlessness. Non-pharmacological approaches proved extremely helpful, but as the disease progressed, we found that in addition to this, a combination of midazolam, levomepromazine and morphine proved the most effective in her syringe driver. All of this care took place within the context of a holistic, multi-disciplinary team, vital for managing the rapidly changing symptoms of this complex disease and its effect on both patient and family. Given its rare nature, there is only limited research on the palliative care aspects of managing terminal sCJD. We therefore hope that by sharing our experience, this case report may prove helpful.

Multichannel pulse high-current driver of magnetic actuator

Magnetic linear actuators have a wide range of applications. Their main advantage is the ease with which they can be controlled by regulating the current. However, high electrical power is required for obtaining a large continuous force, acceleration, and stroke from a device with small dimensions. In this study, we developed a comprehensive open-source system consisting of simple movable iron magnetic actuators, a four-channel controller, and dedicated software. The graphical user interface facilitates the designing of the sequence of piston strokes, including the start time, duration of movement, and force for each stroke separately. The controller generates a high current of pulses, which allows achieving a high force, acceleration, and stroke from small-sized coils while maintaining a relatively safe voltage. The system was originally designed as a reagent syringe driver to control the rapid mixing process used for studying the kinetics of enzymatic reactions. However, this driver may also be applied in various other scientific as well as nonscientific applications.

Coil spring-powered pump with inertial microfluidic chip for size-based isolation and enrichment of biological cells.

Microfluidic chips have been widely used for in vitro diagnostics using pretreatment of biological samples; however, biologists and clinical researchers have difficulties using them in resource-limited settings. Sample injection systems for microfluidic chips are bulky, expensive, electricity-powered, and complex. A coiled spring-powered device, which can be used to isolate variously sized cells with high efficiency continuously and passively, was developed for portable, low-cost, electricity-free, and simple sample injection. The flow driving power was provided by releasing the compression spring in the mechanical syringe driver with a one-click action. In general, a syringe pump generates a stable passive flow rate. However, the syringe pumps are large in size and expensive because they have many functions such as infusion/withdrawal flow injection and the use of syringes of various sizes, allowing them to be applied in a variety of applications performed in the laboratory. In addition, it is not suitable for portable devices because of the considerable amount of electric power required. To overcome these drawbacks, we developed a device prototype that sorts different-sized particles and separates rare tumor cells or blood cells from blood with high efficiency. The performance of the coiled spring-powered device was evaluated and found to be comparable with that of syringe pump-powered devices. In situations where trained personnel cannot handle microfluidic chips for isolating circulating biomarkers (CTCs, WBCs, or plasma) from blood samples, the coiled spring-powered device can provide diagnostic tools, especially in resource-limited countries.

Cross-sectional survey of Australian and New Zealand clinical staff to explore attitudes regarding medication prescription and administration during neonatal emergencies.

To survey Australasian neonatal medical and nursing staff to determine confidence regarding medication use, prior experience with medication errors and common resources utilised in neonatal emergencies. Data were collected through a cross-sectional online survey distributed to clinical staff affiliated with the Australian and New Zealand Neonatal Network. Information collected included: demographics, confidence in medication use, medication errors and resources used to assist with medication administration. Outcomes were compared between medical staff and nursing staff, and between clinical staff with differing levels of clinical experience (<5 years, 5-10 years and >10 years). Respondents (n= 133) were most confident in calculating medication doses (89%, n= 119), but least confident in prescribing medication (50%, n= 67). Nurses were more likely to be confident than doctors with respect to appropriately diluting and drawing up medication (88% nurses vs. 28% doctors, P< 0.0001), and administering intravenous medications to critically ill neonates (97% nurses vs. 82% doctors, P< 0.01). Over half of respondents reported being personally involved in a medication error in the last 12 months: 33% had been involved in an error related to delayed administration, 18% related to incorrect documentation and 17% related to an incorrect dose. Free-text responses highlighted issues relating to adrenaline (epinephrine) administration and difficulties with equipment (syringe drivers and/or infusion pumps). Medication errors in neonatal emergencies are common. Strategies to reduce such errors should be implemented in settings where neonates may require emergency care or resuscitation.

"Palliative Syringe Driver"? A Mixed-Methods Study in Different Hospital Departments on Continuous Infusions of Sedatives and/or Opioids in End-of-Life Care.

ObjectivesContinuous infusions of sedatives and/or opioids (continuous infusions) are frequently used in end-of-life care. Available data indicate challenges in nonspecialist palliative care settings. We aimed to assess the use of continuous infusions during the last week of life in different hospital departments.MethodsIn a sequential mixed-methods design, a retrospective cohort study was followed by consecutive qualitative interviews in 5 German hospital departments. Medical records of 517 patients who died from January 2015 to December 2017 were used, and 25 interviews with physicians and nurses were conducted. Recorded sedatives were those recommended in guidelines for “palliative sedation”: benzodiazepines, levomepromazine, haloperidol (≥5 mg/d), and propofol. Exploratory statistical analysis (R 3.6.1.) and framework analysis of interviews (MAXQDA 2018.2) were performed.ResultsDuring the last week of life, 359 of 517 deceased patients (69%) received continuous infusions. Some interviewees reported that continuous infusions are a kind of standard procedure for “palliative” patients. According to our interviewees’ views, equating palliative care with continuous infusion therapy, insufficient experience regarding symptom control, and fewer care needs may contribute to this approach. In addition, interviewees reported that continuous infusions may be seen as an “overall-concept” for multiple symptoms. Medical record review demonstrated lack of a documented indication for 80 of 359 patients (22%). Some nurses experienced concerns or hesitations among physicians regarding the prescription of continuous infusions.ConclusionsContinuous infusions seem to be common practice. Lack of documented indications and concerns regarding the handling and perception of a “standard procedure” in these highly individual care situations emphasize the need for further exploration and support to ensure high quality of care.

Electricity-free hand-held inertial microfluidic sorter for size-based cell sorting

Conventional batch-top cell sorters are often bulky and expensive, and miniaturized microfluidic sorters available mostly require field generators and electricity-powered pumping systems. Therefore, the development of a low-cost, portable cell sorter that can be used in low resource settings is essential. In this study, we propose such an electricity-free hand-held inertial microfluidic sorter that can be used for the high-efficiency sorting of differently sized cells in a continuous and passive manner. The proposed hand-held sorter is composed of a wheel-shaped all-in-one syringe inertial microfluidic sorter (i-sorter) with flow stabilizer units and two spring-driven mechanical syringe drivers. The release of the compression spring in the mechanical syringe driver through a one-click operation provides the flow driving force. Passive flow stabilizer units in the i-sorter enable flow-rate-sensitive inertial cell separation for the unstable driving flow rate generated by the low-cost mechanical syringe driver. We successfully achieved sorting of differently sized particles and high-efficiency separation of rare tumor cells from the blood using the fabricated prototype. Our hand-held inertial microfluidic cell sorter has many advantages, including low device cost, simple electricity-free operation, compactness, and portability; additionally, samples do not need to be pre-labelled. Therefore, it has potential for use in low-resource settings.

High Precision 3D Printed Syringe Pump for Contact Angle Goniometer

Contact angle goniometer is a tool used to measure the contact angle of a surface which is usually coated with nanomaterial. Contact angle goniometer has an important part, that is syringe pump as a tool for dripping a number of liquids with high precision and accurate flowrate. The function of the syringe pump is to control amount and feedrate of liquid on a milliliter to microliter scale per minute using a simple microcontroller. In this study, this syringe pump used an arduino as a controller and a stepper motor as a syringe driver. Casing and the syringe pump mechanism were designed with AutoCAD Fusion360 software and printed using a 3D printer. This syringe pump has an accuracy value of 99.5%, a precision value of 99.7% and a deviation value 0.4 µL which is based on the solution measured using Mettler Toledo 204 analytical balance. From the result, it is obtained that the syringe pump has been used for the contact angle goniometer with an experiment of water being dripped onto the ABS plastic surface with flowrate 100 µL/minute and the surface contact angle was analyzed using imageJ software and the result of the contact angle was 179°. Therefore, based on the result of this study, it can be concluded that the syringe pump can be used as a contact angle goniometer

Subcutaneous vitamin B12 administration using a portable infusion pump in cobalamin-related remethylation disorders: a gentle and easy to use alternative to intramuscular injections

BackgroundCobalamin (cbl)-related remethylation disorders are a heterogeneous group of inherited disorders comprising the remethylation of homocysteine to methionine and affecting multiple organ systems, most prominently the nervous system and the bone marrow. To date, the parenteral, generally intramuscular, lifelong administration of hydroxycobalamin (OHCbl) is the mainstay of therapy in these disorders. The dosage and frequency of OHCbl is titrated in each patient to the minimum effective dose in order to account for the painful injections. This may result in undertreatment, a possible risk factor for disease progression and disease-related complications.ResultsWe describe parenteral administration of OHCbl using a subcutaneous catheter together with a portable infusion pump in a home therapy setting in four pediatric patients with remethylation disorders, two patients with cblC, one patient with cblG, and one patient with cblE deficiency, in whom intramuscular injections were not or no longer feasible. The placement of the subcutaneous catheters and handling of the infusion pump were readily accomplished and well accepted by the patients and their families. No adverse events occurred. The use of a small, portable syringe driver pump allowed for a most flexible administration of OHCbl in everyday life. The concentrations of total homocysteine levels were determined at regular patient visits and remained within the therapeutic target range. This approach allowed for the continuation of OHCbl therapy or the adjustment of therapy required to improve metabolic control in our patients.ConclusionsSubcutaneous infusion using a subcutaneous catheter system and a portable pump for OHCbl administration in combined and isolated remethylation disorders is safe, acceptable, and effective. It decreases disease burden in preventing frequent single injections and providing patient independence. Thus, it may promote long-term adherence to therapy in patients and parents.

Effect of microaggregate filter passage on feline whole blood stored for 35 days.

The aim of this study was to compare the characteristics of fresh and stored feline red blood cells (RBCs) after passage through an 18 μm microaggregate filter. Nine cats were recruited for a single blood donation using an open collection system. A simulated transfusion using a syringe driver and microaggregate filter was performed over 2 h with half the blood on the day of donation and the other half after 35 days of storage. Differences in haematological parameters, haemolysis percentage and osmotic fragility (OF) were compared on the day of donation pre-filter passage (D0-) vs day of donation post-filter (D0+) or day 35 storage pre-filter (D35-) and post-filter (D35+). Blood was cultured at D0+ and D35+. There were no statistically significant differences in the D0- vs D0+ comparisons. There were statistically significant (P <0.05) increases in haemolysis percentage, red cell distribution width (RDW) percentage and mean OF, and decreases in packed cell volume (PCV), RBC count, haemoglobin and haematocrit for D0- vs D35-. The same was found for D0- vs D35+ with the addition of a significant increase in mean cell haemoglobin (MCH). For D35- vs D35+ only MCH significantly increased. At day 35, 6/9 units had haemolysis percentages that exceeded 1%. This increased to 8/9 of stored units post-filter passage. All blood units cultured negative. Fresh RBCs exhibited no in vitro evidence of injury following passage through an 18 μm microaggregate filter. Increased MCH was observed in the stored blood and may represent haemolysis induced by the filter. All other changes can be explained by storage lesion rather than filter passage. The findings highlight the importance of blood banking quality controls and the need for further research to assess the effects of transfusion technique, specifically filter passage, on storage lesion-affected feline blood.

Multicenter Evaluation of 434 Hospital Deaths From COVID-19: How Can We Improve End-of-Life Care During a Pandemic?

ContextThe pandemic has substantially increased the workload of hospital palliative care providers, requiring them to be responsive and innovative despite limited information on the specific end of life care needs of patients with COVID-19. Multi-site data detailing clinical characteristics of patient deaths from large populations, managed by specialist and generalist palliative care providers are lacking. ObjectivesTo conduct a large multicenter study examining characteristics of COVID-19 hospital deaths and implications for care. MethodsA multi-center retrospective evaluation examined 434 COVID-19 deaths in 5 hospital trusts over the period March 23, 2020 to May 10, 2020. ResultsEighty three percent of patients were over 70.32% were admitted from care homes. Diagnostic timing indicated over 90% of those who died contracted the virus in the community. Dying was recognized in over 90% of patients, with the possibility of dying being identified less than 48 hours from admission for a third. In over a quarter, death occurred less than 24 hours later. Patients who were recognized to be dying more than 72 hours prior to death were most likely to have access to medication for symptom control. ConclusionThis large multicenter study comprehensively describes COVID-19 deaths throughout the hospital setting. Clinicians are alert to and diagnose dying appropriately in most patients. Outcomes could be improved by advance care planning to establish preferences, including whether hospital admission is desirable, and alongside this, support the prompt use of anticipatory subcutaneous medications and syringe drivers if needed. Finally, rapid discharges and direct hospice admissions could better utilize hospice beds and improve care.

Using Task Models to Understand the Intersection of Numeracy Skills and Technical Competence With Medical Device Design

AbstractTask models are used in many different ways throughout the design and development of interactive systems. When the interactive systems are safety critical, task models can play an important role in ensuring system behaviours are consistent with user requirements, which may help to prevent errors. While task models can be used to describe a user’s goals and the steps required to achieve that goal, to understand where user errors may occur we also need to consider the users’ understanding of how to perform a task and how this relates to the system they are using. Our focus is on the use of medical devices such as syringe drivers and infusion pumps for intravenous medication, which forms a major part of hospital inpatient care throughout the world. While we might rely on software engineering and human factors techniques to ensure correctness of such devices, their use by medical personnel in practice includes other factors that are equally important. These include training medical personnel in the use of medical devices. Also numeracy education for medical staff to ensure that they are able to set up and perform the necessary calculations to convert prescribed medication into the appropriate values and measures for their delivery mechanisms. We have developed an approach that aims to bring together concepts of technology design (both functional correctness and usability concerns), numeracy and medication delivery competency. In order to do so we use task models as a common language that enables us to consider these different domains in a single way. We find that the ability to describe the two domains within a single process allows us to compare models of knowledge, tasks and use of devices, which can elicit potential mismatches and problems.