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BACKGROUND AND OBJECTIVES: Patient and Family Centered I-PASS (PFC I-PASS) emphasizes family and nurse engagement, health literacy, and structured communication on family-centered rounds organized around the I-PASS framework (Illness severity-Patient summary-Action items-Situational awareness-Synthesis by receiver). We assessed adherence, safety, and experience after implementing PFC I-PASS using a novel "Mentor-Trio" implementation approach with multidisciplinary parent-nurse-physician teams coaching sites. METHODS: Hybrid Type II effectiveness-implementation study from 2/29/19-3/13/22 with ≥3 months of baseline and 12 months of postimplementation data collection/site across 21 US community and tertiary pediatric teaching hospitals. We conducted rounds observations and surveyed nurses, physicians, and Arabic/Chinese/English/Spanish-speaking patients/parents. RESULTS: We conducted 4557 rounds observations and received 2285 patient/family, 1240 resident, 819 nurse, and 378 attending surveys. Adherence to all I-PASS components, bedside rounding, written rounds summaries, family and nurse engagement, and plain language improved post-implementation (13.0%-60.8% absolute increase by item), all P < .05. Except for written summary, improvements sustained 12 months post-implementation. Resident-reported harms/1000-resident-days were unchanged overall but decreased in larger hospitals (116.9 to 86.3 to 72.3 pre versus early- versus late-implementation, P = .006), hospitals with greater nurse engagement on rounds (110.6 to 73.3 to 65.3, P < .001), and greater adherence to I-PASS structure (95.3 to 73.6 to 72.3, P < .05). Twelve of 12 measures of staff safety climate improved (eg, "excellent"/"very good" safety grade improved from 80.4% to 86.3% to 88.0%), all P < .05. Patient/family experience and teaching were unchanged. CONCLUSIONS: Hospitals successfully used Mentor-Trios to implement PFC I-PASS. Family/nurse engagement, safety climate, and harms improved in larger hospitals and hospitals with better nurse engagement and intervention adherence. Patient/family experience and teaching were not affected.
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Mentors , Teaching Rounds , Humans , Child , Parents , Hospitals, Teaching , Communication , LanguageABSTRACT
OBJECTIVE: To determine the association between inpatient team continuity, defined as the maximum number of days the same student, resident, and attending worked together on the inpatient wards, and the academic performance of students in a pediatric block clerkship. METHODS: We retrospectively identified students who rotated in the pediatric clerkship at a single institution from 2020 to 2022. We used multiple linear regression models to adjust for multiple confounders and used a one-way analysis of variance to compare adjusted outcomes across quartiles of inpatient team continuity. RESULTS: A total of 227 students were included in the analysis. Students' preceptor ratings increased by 0.04 on a scale of 0-4 (95% confidence interval [CI] 0.01-0.06; p = .001), and their final pediatric grade increased by 0.02 on a scale of 0-4 (95% CI 0.01-0.02; p < .001) with each 1-day increase in inpatient team continuity. There was no statistically significant association between team continuity and shelf exam scores or observed structured clinical examination scores. Preceptor ratings and final clerkship grades increased across quartiles of team continuity, with the greatest increase being between the second, 6-7 days of continuity, and third, 8-10 days of continuity, quartiles. CONCLUSIONS: Increased inpatient team continuity is associated with students receiving higher preceptor ratings and achieving a higher final pediatric clerkship grade. While the mechanisms driving these associations remain unknown, the results add to the literature base supporting the importance of preceptor continuity in undergraduate medical education.
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Academic Performance , Clinical Clerkship , Pediatrics , Students, Medical , Humans , Retrospective Studies , Pediatrics/education , Academic Performance/statistics & numerical data , Female , Patient Care Team , Male , Inpatients , Preceptorship , Clinical Competence , Educational MeasurementABSTRACT
OBJECTIVE: To determine if the academic performance of students who worked on a longitudinal inpatient team in the pediatric clerkship differed from students on traditional teams. We hypothesized that working on the longitudinal team would be associated with improved performance. METHODS: We retrospectively identified students who rotated in the pediatric clerkship at a single institution from 2017 through 2021. We used multiple linear and multiple ordered logistic regression to examine whether working on a longitudinal inpatient team in which the majority of students work with the same senior resident and attending for the entire inpatient block and function without interns was associated with improved academic performance. RESULTS: We included data from 463 students, 316 in the longitudinal team group and 147 in the traditional team group. Working on the longitudinal team was associated with a higher inpatient preceptor rating (adjusted mean rating 3, 95% confidence interval [CI] 2.97 to 3.03 vs 2.85, 95% CI 2.81 to 2.90; P = .02; on a scale of 0 to 4) and an increased probability of achieving a higher final grade in the pediatric clerkship (adjusted probability of achieving honors 22%, 95% CI 17% to 28% vs 11%, 95% CI 6% to 16%; P = .003). These differences did not persist in the clerkship immediately after pediatrics. CONCLUSIONS: Compared with a traditional inpatient team, working on a longitudinal team was associated with achieving a higher preceptor rating and final pediatric clerkship grade. Implementing similar models within clinical clerkships may help foster optimal student performance.
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Academic Performance , Clinical Clerkship , Students, Medical , Humans , Child , Retrospective Studies , InpatientsABSTRACT
Introduction: Patient and family-centered rounds (PFCRs) are an important element of family-centered care often used in the inpatient pediatric setting. However, techniques and best practices vary, and faculty, trainees, nurses, and advanced care providers may not receive formal education in strategies that specifically enhance communication on PFCRs. Methods: Harnessing the use of structured communication, we developed the Patient and Family-Centered I-PASS Safer Communication on Rounds Every Time (SCORE) Program. The program uses a standardized framework for rounds communication via the I-PASS mnemonic, principles of health literacy, and techniques for patient/family engagement and bidirectional communication. The resident and advanced care provider training materials, a component of the larger SCORE Program, incorporate a flipped classroom approach as well as interactive exercises, simulations, and virtual learning options to optimize learning and retention via a 90-minute workshop. Results: Two hundred forty-six residents completed the training and were evaluated on their knowledge and confidence regarding key elements of the curriculum. Eighty-eight percent of residents agreed/strongly agreed that after training they could activate and engage families and all members of the interprofessional team to create a shared mental model; 90% agreed/strongly agreed that they could discuss the roles/responsibilities of various team members during PFCRs. Discussion: The Patient and Family-Centered I-PASS SCORE Program provides a structured framework for teaching advanced communication techniques that can improve provider knowledge of and confidence with engaging and communicating with patients/families and other members of the interprofessional team during PFCRs.
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Communication , Teaching Rounds , Child , Curriculum , Humans , Inpatients , Teaching Rounds/methodsABSTRACT
INTRODUCTION: Diagnostic error is a prevalent type of medical error that is associated with considerable patient harm and increased medical costs. The majority of literature guiding the current understanding of diagnostic error in the hospital setting is from adult studies. However, there is research to suggest this type of error is also prevalent in the pediatric specialty. OBJECTIVES: The primary objective of this study was to define the current understanding of diagnostic error in the pediatric hospital through a structured literature review. METHODS: We searched PubMed and identified studies focusing on three aspects of diagnostic error in pediatric hospitals: the incidence or prevalence, contributing factors, and related interventions. We used a tiered review, and a standardized electronic form to extract data from included articles. RESULTS: Fifty-nine abstracts were screened and 23 full-text studies were included in the final review. Seventeen of the 23 studies focused on the incidence or prevalence, with only 3 studies investigating the utility of interventions. Most studies took place in an intensive care unit or emergency department with very few studies including only patients on the general wards. Overall, the prevalence of diagnostic error in pediatric hospitals varied greatly and depended on the measurement technique and specific hospital setting. Both healthcare system factors and individual cognitive factors were found to contribute to diagnostic error, with there being limited evidence to guide how best to mitigate the influence of these factors on the diagnostic process. CONCLUSION: The general knowledge of diagnostic error in pediatric hospital settings is limited. Future work should incorporate structured frameworks to measure diagnostic errors and examine clinicians' diagnostic processes in real-time to help guide effective hospital-wide interventions.
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Emergency Service, Hospital , Hospitals, Pediatric , Adult , Child , Diagnostic Errors , Humans , Incidence , PrevalenceSubject(s)
Bullying/prevention & control , Schools, Medical/organization & administration , Students, Medical , Systems Analysis , Adult , Curriculum , Female , Humans , Male , Root Cause Analysis , UtahABSTRACT
INTRODUCTION: National trends toward empowering and enabling patients and families to take a bigger role in their own medical care and enhanced collaboration between rounding stakeholders have effectuated a new rounding model in the pediatric inpatient setting known as 'Patient- and Family-Centered Rounds/I-PASS,' which has shown to decrease safety events and to improve stakeholders' experience with rounding. Other enhancements to the new model, such as the use of whiteboards, rounding checklists, and facecards, have all been applied to the new model to good effect. Another major enhancement to rounding of late has been the application of a schedule to rounds, which has increased the presence of the nurse and the family during rounds and has improved rounding efficiency without a negative effect on teaching. OBJECTIVE: We provide a review of the literature regarding this new rounding model and its effects in the pediatric inpatient setting, as well as a review of the enhancements that have been applied to the new model, the recognized barriers to the implementation of these rounding alterations and the ways in which those barriers have been overcome. CONCLUSIONS: In the pediatric inpatient setting, the 'Patient and Family-Centered Rounds/IPASS' rounding model, as well as enhancements to this new model such as rounding schedules, whiteboards, checklists and facecards, have had a positive effect on stakeholders' experience with rounding, increased patient safety and improved rounding efficiency. Given these positive effects, these alterations to rounding should be promoted and sustained. PLAIN LANGUAGE SUMMARY: Rounding is when a medical care provider, or a team of providers, visits patients in the hospital in order to determine a plan of care and discuss that care with the patient and the patient's family. In teaching hospitals, this involves staff physicians, medical trainees and advanced practice providers. Rounding has changed in the recent past as evolving pressures have increasingly led these teams of providers to talk and make decisions about patients outside the patient's room, which lessens the patient's ability to contribute to decision-making. This also lessens the ability of the patient's nurse to contribute. The recognition of this problem has led to big changes in rounding in children's teaching hospitals, the biggest of which is called 'family-centered rounding.' This involves performing the entirety of rounds in the patients' rooms, directing the discussion toward them in language that they understand, with the active participation of everyone present, including the patient's nurse. Other changes in rounding, designed to improve patients' experiences and decrease medical errors, have made this new rounding model even better. Structured communication during rounds, communication aids such as whiteboards and checklists, and planned times for rounding on each patient ('scheduled rounding') have all successfully been used to improve patients' care and experience in the hospital. This article aims to inform the reader about family-centered rounds and other recent rounding transformations that have proven to increase patient safety and improve their experience while in the hospital, also noting barriers to these changes and how they have been overcome.
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Teaching Rounds , Child , Communication , Hospitals, Pediatric , Hospitals, Teaching , Humans , Patient Care , Patient Care Team , United StatesABSTRACT
There are no program evaluation approaches designed for a crisis, such as the COVID-19 pandemic. It is critical to evaluate the educational impact of COVID-19 to keep administrators informed and guide decision-making. The authors used systems thinking to design an evaluation model. The evaluation results suggest complex interactions between individuals and course level changes due to COVID-19. Specifically, year 1-2 students found more education metrics lacking relative to year 3-4 students, faculty, and course directors. There was no consensus for the value of similar instructional/assessment adaptations. The evaluation model can be adapted by other medical schools to fit systems-based needs.
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Introduction: Planning for and responding to happenstance is an important but rarely discussed part of the professional development of medical students. We noted this gap while conducting a study of career inflection points of 24 physicians who frequently mentioned how luck had shaped their unfolding careers. A review of the career counseling literature led us to a body of work known as Planned Happenstance Learning Theory (PHLT). PHLT focuses on the attitudes and skills to make happenstance a positive force in one's life. We found no reference to this work in the medical education literature and resolved to address this gap. Methods: We created resources for an interactive, 90-minute faculty development workshop. In the workshop, the facilitator used a PowerPoint presentation, vignettes of happenstance, a student testimonial, and a reflection worksheet. We presented and formally evaluated the workshop at three national meetings for health science educators. Results: Workshop participants, mostly faculty (N = 45), consistently expressed positive regard for the workshop content, organization, and instructional methods, especially the opportunity for guided reflection. A retrospective pre/postevaluation revealed a meaningful increase in knowledge about PHLT attitudes and skills, as well as a commitment to use these skills in promoting professional development. Discussion: The skills and attitudes of PHLT are relevant to students' career development. A workshop designed to introduce PHLT skills and attitudes to faculty advisors and mentors can help prepare faculty to promote students' awareness and use of these attitudes and skills.
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Education, Medical , Students, Medical , Faculty , Humans , Mentors , Retrospective StudiesABSTRACT
Bedside rounds have evolved concurrently with hospitalist medicine and patient-centered care. Family-centered rounds are the foundation of effective communication in the in-patient pediatric setting. Participant perspectives (family members, patients, nurses, faculty, and trainees) on family-centered rounds differ and goals may not always align. Further, the practical components of how rounds are conducted varies and have continued opportunities for improvement. This article summarizes the most recent experience with rounds in an attempt to identify unified and effective strategies moving forward.
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Child, Hospitalized , Hospital Medicine , Patient-Centered Care , Professional-Family Relations , Teaching Rounds , Child , Forecasting , HumansABSTRACT
OBJECTIVE: To determine whether medical errors, family experience, and communication processes improved after implementation of an intervention to standardize the structure of healthcare provider-family communication on family centered rounds. DESIGN: Prospective, multicenter before and after intervention study. SETTING: Pediatric inpatient units in seven North American hospitals, 17 December 2014 to 3 January 2017. PARTICIPANTS: All patients admitted to study units (3106 admissions, 13171 patient days); 2148 parents or caregivers, 435 nurses, 203 medical students, and 586 residents. INTERVENTION: Families, nurses, and physicians coproduced an intervention to standardize healthcare provider-family communication on ward rounds ("family centered rounds"), which included structured, high reliability communication on bedside rounds emphasizing health literacy, family engagement, and bidirectional communication; structured, written real-time summaries of rounds; a formal training programme for healthcare providers; and strategies to support teamwork, implementation, and process improvement. MAIN OUTCOME MEASURES: Medical errors (primary outcome), including harmful errors (preventable adverse events) and non-harmful errors, modeled using Poisson regression and generalized estimating equations clustered by site; family experience; and communication processes (eg, family engagement on rounds). Errors were measured via an established systematic surveillance methodology including family safety reporting. RESULTS: The overall rate of medical errors (per 1000 patient days) was unchanged (41.2 (95% confidence interval 31.2 to 54.5) pre-intervention v 35.8 (26.9 to 47.7) post-intervention, P=0.21), but harmful errors (preventable adverse events) decreased by 37.9% (20.7 (15.3 to 28.1) v 12.9 (8.9 to 18.6), P=0.01) post-intervention. Non-preventable adverse events also decreased (12.6 (8.9 to 17.9) v 5.2 (3.1 to 8.8), P=0.003). Top box (eg, "excellent") ratings for six of 25 components of family reported experience improved; none worsened. Family centered rounds occurred more frequently (72.2% (53.5% to 85.4%) v 82.8% (64.9% to 92.6%), P=0.02). Family engagement 55.6% (32.9% to 76.2%) v 66.7% (43.0% to 84.1%), P=0.04) and nurse engagement (20.4% (7.0% to 46.6%) v 35.5% (17.0% to 59.6%), P=0.03) on rounds improved. Families expressing concerns at the start of rounds (18.2% (5.6% to 45.3%) v 37.7% (17.6% to 63.3%), P=0.03) and reading back plans (4.7% (0.7% to 25.2%) v 26.5% (12.7% to 7.3%), P=0.02) increased. Trainee teaching and the duration of rounds did not change significantly. CONCLUSIONS: Although overall errors were unchanged, harmful medical errors decreased and family experience and communication processes improved after implementation of a structured communication intervention for family centered rounds coproduced by families, nurses, and physicians. Family centered care processes may improve safety and quality of care without negatively impacting teaching or duration of rounds. TRIAL REGISTRATION: ClinicalTrials.gov NCT02320175.
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Medical Errors/statistics & numerical data , Patient Safety/statistics & numerical data , Patient-Centered Care/methods , Professional-Family Relations , Adult , Child , Child, Preschool , Communication , Family , Female , Humans , Inpatients , Male , North America , Patient Care Team/statistics & numerical data , Patient Participation , Program Evaluation/methods , Prospective StudiesABSTRACT
Importance: Medical errors and adverse events (AEs) are common among hospitalized children. While clinician reports are the foundation of operational hospital safety surveillance and a key component of multifaceted research surveillance, patient and family reports are not routinely gathered. We hypothesized that a novel family-reporting mechanism would improve incident detection. Objective: To compare error and AE rates (1) gathered systematically with vs without family reporting, (2) reported by families vs clinicians, and (3) reported by families vs hospital incident reports. Design, Setting, and Participants: We conducted a prospective cohort study including the parents/caregivers of 989 hospitalized patients 17 years and younger (total 3902 patient-days) and their clinicians from December 2014 to July 2015 in 4 US pediatric centers. Clinician abstractors identified potential errors and AEs by reviewing medical records, hospital incident reports, and clinician reports as well as weekly and discharge Family Safety Interviews (FSIs). Two physicians reviewed and independently categorized all incidents, rating severity and preventability (agreement, 68%-90%; κ, 0.50-0.68). Discordant categorizations were reconciled. Rates were generated using Poisson regression estimated via generalized estimating equations to account for repeated measures on the same patient. Main Outcomes and Measures: Error and AE rates. Results: Overall, 746 parents/caregivers consented for the study. Of these, 717 completed FSIs. Their median (interquartile range) age was 32.5 (26-40) years; 380 (53.0%) were nonwhite, 566 (78.9%) were female, 603 (84.1%) were English speaking, and 380 (53.0%) had attended college. Of 717 parents/caregivers completing FSIs, 185 (25.8%) reported a total of 255 incidents, which were classified as 132 safety concerns (51.8%), 102 nonsafety-related quality concerns (40.0%), and 21 other concerns (8.2%). These included 22 preventable AEs (8.6%), 17 nonharmful medical errors (6.7%), and 11 nonpreventable AEs (4.3%) on the study unit. In total, 179 errors and 113 AEs were identified from all sources. Family reports included 8 otherwise unidentified AEs, including 7 preventable AEs. Error rates with family reporting (45.9 per 1000 patient-days) were 1.2-fold (95% CI, 1.1-1.2) higher than rates without family reporting (39.7 per 1000 patient-days). Adverse event rates with family reporting (28.7 per 1000 patient-days) were 1.1-fold (95% CI, 1.0-1.2; P = .006) higher than rates without (26.1 per 1000 patient-days). Families and clinicians reported similar rates of errors (10.0 vs 12.8 per 1000 patient-days; relative rate, 0.8; 95% CI, .5-1.2) and AEs (8.5 vs 6.2 per 1000 patient-days; relative rate, 1.4; 95% CI, 0.8-2.2). Family-reported error rates were 5.0-fold (95% CI, 1.9-13.0) higher and AE rates 2.9-fold (95% CI, 1.2-6.7) higher than hospital incident report rates. Conclusions and Relevance: Families provide unique information about hospital safety and should be included in hospital safety surveillance in order to facilitate better design and assessment of interventions to improve safety.
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Child, Hospitalized/statistics & numerical data , Hospitals, Pediatric/statistics & numerical data , Medical Errors/statistics & numerical data , Adult , Child , Cohort Studies , Family , Female , Humans , Male , Prospective Studies , United StatesABSTRACT
The availability of mortality data for any society plays an essential role in health monitoring and evaluation, as well as in the design of health interventions. However, most resource-poor countries such as Ghana have no reliable vital registration system. In these instances, verbal autopsy (VA) may be used as an alternative method to gather mortality data. In rural Ghana, the research team utilized a VA questionnaire to interview caretakers who were present with a child under the age of five prior to death. The data was given to two physicians who independently assigned the most probable cause of death for the child. A third, blinded physician analyzed the data in the cases where the first two physicians disagreed. When there was agreement between physicians, this was assigned as the cause of death for the individual child. During the study period, we recorded 118 deaths from 92 households. Twenty-nine (24.6%) were neonatal deaths with the leading causes of death being neonatal sepsis, birth asphyxia and pneumonia. The remaining 89 (75.4%) were post-neonatal deaths with the most common causes of death being pneumonia, malaria and malnutrition. While 63/118 (53.4%) deaths occurred in the home, there is no statistically significant relationship between the location of the home and the time of travel to the nearest health facility (P=0.132). VA is an important epidemiological tool for obtaining mortality data in communities that lack reliable vital registration systems. Improvement in health care is necessary to address the large number of deaths occurring in the home.
ABSTRACT
The availability of mortality data for any society plays an essential role in health monitoring and evaluation; as well as in the design of health interventions. However; most resource-poor countries such as Ghana have no reliable vital registration system. In these instances; verbal autopsy (VA) may be used as an alternative method to gather mortality data. In rural Ghana; the research team utilized a VA questionnaire to interview caretakers who were present with a child under the age of five prior to death. The data was given to two physicians who independently assigned the most probable cause of death for the child. A third; blinded physician analyzed the data in the cases where the first two physicians disagreed. When there was agreement between physicians; this was assigned as the cause of death for the individual child. During the study period; we recorded 118 deaths from 92 households. Twenty-nine (24.6) were neonatal deaths with the leading causes of death being neonatal sepsis; birth asphyxia and pneumonia. The remaining 89 (75.4) were post-neonatal deaths with the most common causes of death being pneumonia; malaria and malnutrition. While 63/118 (53.4) deaths occurred in the home; there is no statistically significant relationship between the location of the home and the time of travel to the nearest health facility (P=0.132). VA is an important epidemiological tool for obtaining mortality data in communities that lack reliable vital registration systems. Improvement in health care is necessary to address the large number of deaths occurring in the home
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Autopsy , Cause of Death , Infant , Infant, Newborn , Signs and SymptomsABSTRACT
An on-chip micropump for portable microfluidic applications was investigated using mathematical modeling and experimental testing. This micropump is activated by the addition of water, via a dropper, to ionic polymer particles that swell due to osmotic effects when wetted. The resulting particle volume increase deflects a membrane, forcing a separate fluid from an adjacent reservoir. The micropump components, along with the microfluidic components, are fabricated using the contact liquid photolithographic polymerization (CLiPP) method. The maximum flow rate achieved with this pump is 17 microL per minute per mg of dry polymer particles of 355-425 microm in diameter. The pump flow rate may be controlled by adjusting the particle size and amount, the membrane properties, and the channel dimensions. The experimental results demonstrate good agreement with an analytical model describing the particle swelling and its coupling with resistive forces from the bending membrane, viscous flow in the microchannel, and interfacial effects. Key features of this micropump are that it can be placed directly on a microdevice, and that it requires only a small amount of water and no external power supply to function. Therefore, this pumping system is useful for applications in which a highly portable device is required.
Subject(s)
Microfluidic Analytical Techniques/methods , Nanotechnology , Polymers/chemistry , Water/chemistry , Microfluidic Analytical Techniques/instrumentation , Models, Theoretical , Osmosis , Particle Size , Surface Properties , Time FactorsABSTRACT
A water-activated, effervescent reaction was used to transport fluid in a controllable manner on a portable microfluidic device. The reaction between sodium bicarbonate and an organic acid, tartaric acid and/or benzoic acid, was modeled to analyze methods of controlling the generation of carbon-dioxide gas for the purposes of pumping fluids. Integration and testing of the effervescent reaction pump in a microfluidic device was made possible by using elastomeric polymers as both photopolymerizable septa and removable lids. These materials combined to enable facile access to otherwise gas-tight devices. Based on theoretical predictions for 0.33 mg of sodium bicarbonate and a stoichiometric amount of organic acid, the pumping flow rate could be varied from 0.01 microL s(-1) to 70 microL s(-1). The flow rate is controlled by adjusting any or all of the particle size of the least soluble reactant, the amount of reactants used, and the type of organic acid selected. The tartaric acid systems rapidly produce carbon dioxide; however, the gas generation rates dramatically decrease over the course of the reaction. In contrast, carbon dioxide production rate in the benzoic acid systems is lower and nearly constant for several minutes. Water activation and direct placement on a microfluidic device are key features of this micropump, which is therefore useful for portable microfluidic applications.
Subject(s)
Microfluidics/instrumentation , Microfluidics/methodsABSTRACT
Novel fabrication techniques and polymer systems are being explored to enable mass production of low cost microfluidic devices. In this contribution we discuss a new fabrication scheme for making microfluidic devices containing porous polymer components in situ. Contact lithography, a living radical photopolymer (LRPP) system and salt leaching were used to fabricate multilayer microfluidic devices rapidly with various channel geometries and covalently attached porous polymer plugs made of various photopolymerizable substrates. LRPP systems offer the advantages of covalent attachment of microfluidic device layers and facile surface modification via grafting. Several applications of the porous plugs are also explored, including a static mixer, a high surface area-to-volume reactor and a rapidly responding hydrogel valve. Quantitative and qualitative data show an increase in mixing of a fluorescein and a water stream for channels containing porous plugs relative to channels with no porous plugs. Confocal laser scanning microscopy images demonstrate the ability to graft a functional material onto porous plug surfaces. A reaction was carried out on the grafted pore surfaces, which resulted in fluorescent labelling of the grafted material throughout the pores of the plug. Homogenous fluorescence throughout the depth of the porous plug and along pore surfaces indicated that the porous plugs were surface modified by grafting and that reactions can be carried out on the pore surfaces. Finally, porous hydrogel valves were fabricated which swelled in response to contact with various pH solutions. Results indicate that a porous hydrogel valve will swell and close more rapidly than other valve geometries made with the same polymer formulation. The LRPP-salt leaching method provides a means for rapidly incorporating porous polymer components into microfluidic devices, which can be utilized for a variety of pertinent applications upon appropriate selection of porous plug materials and surface treatments.
ABSTRACT
Microfluidic devices are commonly fabricated in silicon or glass using micromachining technology or elastomers using soft lithography methods; however, invariable bulk material properties, limited surface modification methods and difficulty in fabricating high aspect ratio devices prevent these materials from being utilized in numerous applications and/or lead to high fabrication costs. Contact Liquid Photolithographic Polymerization (CLiPP) was developed as an alternative microfabrication approach that uniquely exploits living radical photopolymerization chemistry to facilitate surface modification of device components, fabrication of high aspect ratio structures from many different materials with numerous covalently-adhered layers and facile construction of three-dimensional devices. This contribution describes CLiPP and demonstrates unique advantages of this new technology for microfabrication of polymeric microdevices. Specifically, the procedure for fabricating devices with CLiPP is presented, the living radical photopolymerization chemistry which enables this technology is described, and examples of devices made using CLiPP are shown.