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1.
J Asthma ; 59(2): 315-324, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33198536

RESUMO

INTRODUCTION: The Hospital Asthma Severity Score (HASS) was developed to communicate inpatient asthma severity between providers. The purpose of this prospective study was to validate the HASS against the Pediatric Respiratory Assessment Measure (PRAM) and spirometry for assessment of inpatient asthma exacerbation severity in patients 2-18 years old, at a single point-in-time. METHODS: This study was registered with clinicaltrials.gov (NCT02782065). Children admitted to a tertiary care, free-standing children's hospital were assessed for asthma severity using the HASS, PRAM, and pulmonary function by spirometry. Inter-rater agreement of HASS and PRAM scores was assessed between two blinded clinician raters. Spirometry results were obtained by a certified pulmonary laboratory technician and correlated with HASS and PRAM scores. RESULTS: The sample included 58 subjects. Allowing for a one-point difference in continuous HASS and PRAM scores, inter-rater agreement was 79% for the HASS and 60% for the PRAM. When the scores were categorized as mild, moderate, and severe, inter-rater agreement was 62% for the HASS and 93% for the PRAM (p < .0001). Additionally, intra-rater agreement between HASS and PRAM severity categories was 71% for Rater 1 and 64% for Rater 2. A weak correlation was noted between both the HASS and FEV1 (r = -0.31; p = 0.11), and PRAM and FEV1 (r = -0.30; p = 0.11) for the 29 subjects with acceptable spirometry results. CONCLUSIONS: The HASS and PRAM have acceptable inter-rater and intra-rater agreement. These results support validation of the HASS for managing hospitalized patients during asthma exacerbations.


Assuntos
Asma , Adolescente , Asma/diagnóstico , Criança , Pré-Escolar , Hospitais , Humanos , Estudos Prospectivos , Índice de Gravidade de Doença , Espirometria/métodos
2.
J Pediatr Nurs ; 34: 10-16, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28342694

RESUMO

PURPOSE: Hospital discharge for children with medical complexity (CMC) can be challenging for families. Home visits could potentially benefit CMC and their families after leaving the hospital. We assessed the utility of post-discharge home visits to identify and address health problems for recently hospitalized CMC. DESIGN AND METHODS: A prospective study of 36 CMC admitted to a children's hospital from 4/15/2015 to 4/14/2016 identified with a possible high risk of hospital readmission and offered a post-discharge home visit within 72h of discharge. The visit was staffed by a hospital nurse familiar with the child's admission. The home visit goals were to reinforce education of the discharge plan, assess the child's home environment, and identify and address any problems or issues that emerged post-discharge. RESULTS: The children's median age was 6years [interquartile range (IQR) 2-18]. The median distance from hospital to their home was 38miles (IQR 8-78). All (n=36) children had multiple chronic conditions; 89% (n=32) were assisted with medical technology. The nurse identified and helped with a post-discharge problem during every (n=36) visit. Of the 147 problems identified, 26.5% (n=39) pertained to social/family issues (e.g., financial instability), 23.8% (n=35) medications (e.g., wrong dose), 20.4% (n=30) durable medical equipment (e.g., insufficient supply or faulty function), 20.4% (n=30) child's home environment (e.g., unsafe sleeping arrangement), and 8.8% (n=13) child's health (e.g., unresolved health problem). CONCLUSIONS: Home visits helped identify and address post-discharge issues that occurred for discharged CMC. PRACTICAL IMPLICATIONS: Hospitals should consider home visits when optimizing discharge care for CMC.


Assuntos
Serviços de Assistência Domiciliar/organização & administração , Visita Domiciliar/estatística & dados numéricos , Alta do Paciente , Transferência de Pacientes/métodos , Criança , Pré-Escolar , Estudos de Coortes , Crianças com Deficiência , Hospitais Pediátricos , Humanos , Masculino , Multimorbidade , Projetos Piloto , Estudos Prospectivos , Qualidade de Vida , Resultado do Tratamento , Estados Unidos
3.
Acad Pediatr ; 24(3): 503-505, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37652160

RESUMO

OBJECTIVE: Pediatric researchers use Agency for Healthcare Research and Quality (AHRQ) Kids' Inpatient Database (KID) and National Inpatient Sample (NIS) to analyze the national resource use and outcomes of hospitalized children. Inherent KID-NIS sampling design differences may yield disparate findings. We compared discharge counts and length of stay (LOS) between KID and NIS for common and rare reasons for hospitalization. METHODS: Retrospective analysis of differences in discharges counts and geometric mean LOS for children ages 0-20 years from KID and NIS in 2019, measured for normal newborns and 331 additional reasons for admission, distinguished by All-Payer Refined Diagnosis Related Groups (APR-DRG) and categorized in deciles by annual discharge volume. We followed AHRQ instructions for data clustering, stratification, and weighting to accommodate the KID and NIS designs, including random samples of 80% and 20% of pediatric discharges, respectively, per hospital. RESULTS: KID-NIS differences in national estimates for total annual discharge counts differed by only 0.5% for normal newborns and 3.7% for all other admission reasons in children. KID-NIS differences remained small aside from reasons for admission in the two lowest volume deciles: 9.5% (SD 7.9%) for admission volumes 200-520; 41.1% (SD 64.2%) for volumes <200. KID-NIS LOS differences for these two-lowest volume deciles were 7.9% (SD 7.1%) and 26.0% (SD 29.3%), respectively. CONCLUSIONS: Although KID-NIS differences in discharge counts and LOS were small for high-volume admissions, the differences increased with reasons for admission that had annual discharge volumes approximately 500 or less. For study populations with discharge counts <500, KID may be preferred, given its higher sampling of discharges per hospital.


Assuntos
Hospitalização , Pacientes Internados , Criança , Humanos , Recém-Nascido , Estados Unidos , Estudos Retrospectivos , Tempo de Internação , Alta do Paciente , Bases de Dados Factuais
4.
J Clin Monit Comput ; 26(3): 197-205, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22526738

RESUMO

OBJECTIVES: The primary aim of the study was to determine the changes, if any, in cardiac output (CO) and stroke volume (SV) in normal infants with RSV bronchiolitis. The secondary aim was to determine whether changes in CO (ΔCO) and SV (ΔSV) are associated with changes in respiratory rate (ΔRR). METHODS: Non-invasive CO recordings were obtained within 24 h of admission and discharge. Changes in CO, SV, and HR measurements were compared using paired t-tests. The effect of fluid boluses during the first 24 h (<60 or ≥60 cc/kg) on CO was assessed by 2 way ANOVA with time and group as main effect. The relationship between ΔRR and ΔCO or ΔSV was assessed by linear regression. Data is presented as Mean ± SEM and mean differences with 95 % confidence interval (p < 0.05 considered significant). RESULTS: 15 infants with RSV bronchiolitis were studied. CO (1.31 ± 0.13 to 1.11 ± 0.11 l/min (0.21 [0.04-0.37]) and SV (9.42 ± 1.10 to 7.75 ± 0.83 ml/beat (1.67 [0.21-3.12]) decreased significantly while HR (142.1 ± 4.0 to 145.2 ± 3.1 beats/min 3.0 [-5.3 to 11.3]) was unchanged. SV (p = 0.02) and CO (p = 0.04) significantly decreased only in the 7 infants that received ≥60 cc/kg. ΔRR correlated significantly with ΔCO (r (2) = 0.28, p = 0.04); but not with ΔSV (r (2) = 0.20, p = 0.09). CONCLUSIONS: ∆CO was related to ΔSV and not Δ HR. The ∆CO and ΔSV were affected by fluid boluses. ΔRR correlated with ΔCO. Non-invasive CO monitoring can trend CO and SV in infants with bronchiolitis during hospitalization.


Assuntos
Bronquiolite/fisiopatologia , Débito Cardíaco , Monitorização Fisiológica/métodos , Infecções por Vírus Respiratório Sincicial/fisiopatologia , Vírus Sincicial Respiratório Humano , Volume Sistólico , Bronquiolite/complicações , Feminino , Frequência Cardíaca , Humanos , Lactente , Recém-Nascido , Masculino , Monitorização Fisiológica/estatística & dados numéricos , Miocardite/diagnóstico , Miocardite/etiologia , Miocardite/fisiopatologia , Estudos Prospectivos , Taxa Respiratória , Infecções por Vírus Respiratório Sincicial/complicações
5.
Pediatr Pulmonol ; 57(5): 1223-1228, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35182050

RESUMO

BACKGROUND: Asthma is a leading cause of pediatric hospitalization in the United States. Children hospitalized with asthma are often managed in different care settings during hospitalization, posing challenges to accurate communication among care providers about illness severity. Our objective was to study the feasibility, reliability, and safety of a new pediatric hospital-wide asthma severity score (HASS) across different care units within a single tertiary-care pediatric center. METHODS: 150 patients between the ages of 2 and 18 years hospitalized with a principal diagnosis of status asthmaticus were included in this study. Study patients were followed from the time of initial triage in the emergency department until the time of medical readiness for discharge. Rates of medical errors, early transfers to a higher level of care and medically indicated hospital length of stay (LOS) were compared between 75 patients before and 75 patients after widespread implementation of the HASS using retrospective chart review and anonymous staff reporting. Interrater reliability was determined by collecting independent HASS scores from blinded staff members after tandem or simultaneous patient assessment. RESULTS: Interrater reliability among untrained staff members using the HASS was high. Hospital LOS, rates of adverse events, medical errors, and early transfer to a higher level of care were not significantly different before and after widespread HASS implementation. CONCLUSION: The HASS is a reliable asthma severity tool that can be used throughout hospitalization and among multiple clinical providers to trend clinical progress and optimize communication, particularly during times of care handoffs.


Assuntos
Asma , Hospitais Pediátricos , Adolescente , Asma/diagnóstico , Criança , Pré-Escolar , Serviço Hospitalar de Emergência , Hospitalização , Humanos , Tempo de Internação , Reprodutibilidade dos Testes , Estudos Retrospectivos , Índice de Gravidade de Doença , Triagem , Estados Unidos
6.
J Patient Saf ; 18(1): e156-e162, 2022 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-32398538

RESUMO

OBJECTIVES: We sought to characterize the nature and prevalence of medication order errors (MOEs) occurring at hospital admission for children with medical complexity (CMC), as well as identify the demographic and clinical risk factors for CMC experiencing MOEs. METHODS: Prospective cohort study of 1233 hospitalizations for CMC from November 1, 2015, to October 31, 2016, at 2 children's hospitals. Medication order errors at admission were identified prospectively by nurse practitioners and a pharmacist through direct patient care. The primary outcome was presence of at least one MOE at hospital admission. Statistical methods used included χ2 test, Fisher exact tests, and generalized linear mixed models. RESULTS: Overall, 6.1% (n = 75) of hospitalizations had ≥1 MOE occurring at admission, representing 112 total identified MOEs. The most common MOEs were incorrect dose (41.1%) and omitted medication (34.8%). Baclofen and clobazam were the medications most commonly associated with MOEs. In bivariable analyses, MOEs at admission varied significantly by age, assistance with medical technology, and numbers of complex chronic conditions and medications (P < 0.05). In multivariable analysis, patients receiving baclofen had the highest adjusted odds of MOEs at admission (odds ratio, 2.2 [95% confidence interval, 1.2-3.8]). CONCLUSIONS: Results from this study suggest that MOEs are common for CMC at hospital admission. Children receiving baclofen are at significant risk of experiencing MOEs, even when orders for baclofen are correct. Several limitations of this study suggest possible undercounting of MOEs during the study period. Further investigation of medication reconciliation processes for CMC receiving multiple chronic, home medications is needed to develop effective strategies for reducing MOEs in this vulnerable population.


Assuntos
Erros de Medicação , Reconciliação de Medicamentos , Criança , Hospitalização , Hospitais Pediátricos , Humanos , Admissão do Paciente , Estudos Prospectivos
7.
Int J Biochem Cell Biol ; 40(12): 2720-38, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18620888

RESUMO

Mesenchymal cells are natural tissue builders. They exhibit an extraordinary capacity to metamorphize into differentiated cells, using extrinsic spatial and temporal inputs and intrinsic algorithms, as well as to build and adapt their own habitat. In addition to providing a habitat for osteoprogenitor cells, tissues of the skeletal system provide mechanical support and protection for the multiple organs of vertebrate organisms. This review examines the role of mechanics on determination of cell fate during pre-, peri- and postnatal development of the skeleton as well as during tissue genesis and repair in postnatal life. The role of cell mechanics is examined and brought into context of intrinsic cues during mesenchymal condensation. Remarkable new insights regarding structure function relationships in mesenchymal stem cells, and their influence on determination of cell fate are integrated in the context of de novo tissue generation and postnatal repair. Key differences in the formation of osteogenic and chondrogenic condensations are discussed in relation to direct intramembranous and indirect endochondral ossification. New approaches are discussed to elucidate and exploit extrinsic cues to generate tissues in the laboratory and in the clinic.


Assuntos
Fenômenos Fisiológicos Celulares , Mecanotransdução Celular/fisiologia , Células-Tronco Mesenquimais/citologia , Osteogênese/fisiologia , Diferenciação Celular , Linhagem da Célula , Previsões , Modelos Biológicos , Osteoblastos/citologia , Osteócitos/citologia , Osteogênese/genética , Engenharia Tecidual
8.
J Healthc Qual ; 40(2): 79-88, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29329135

RESUMO

BACKGROUND: Discharging hospitalized children involves several different components, but their relative value is unknown. We assessed which discharge components are perceived as most and least important by clinicians. METHODS: March and June of 2014, we conducted an online discrete choice experiment (DCE) among national societies representing 704 nursing, physician, case management, and social work professionals from 46 states. The DCE consisted of 14 discharge care components randomly presented two at a time for a total of 28 choice tasks. Best-worst scaling of participants' choices generated mean relative importance (RI) scores for each component, which allowed for ranking from least to most important. RESULTS: Participants, regardless of field or practice setting, perceived "Discharge Education/Teach-Back" (RI 11.1 [95% confidence interval, CI: 11.0-11.3]) and "Involve the Child's Care Team" (RI 10.6 [95% CI: 10.4-10.8]) as the most important discharge components, and "Information Reconciliation" (RI 4.1 [95% CI: 3.9-4.4]) and "Assigning Roles/Responsibilities of Discharge Care" (RI 2.8 [95% CI: 2.6-3.0]) as least important. CONCLUSIONS: A diverse group of pediatric clinicians value certain components of the pediatric discharge care process much more than others. Efforts to optimize the quality of hospital discharge for children should consider these findings.


Assuntos
Atitude do Pessoal de Saúde , Pessoal de Saúde/psicologia , Hospitais Pediátricos/estatística & dados numéricos , Hospitais Pediátricos/normas , Alta do Paciente/estatística & dados numéricos , Alta do Paciente/normas , Guias de Prática Clínica como Assunto , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Estados Unidos
9.
Hosp Pediatr ; 8(5): 280-287, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29626010

RESUMO

OBJECTIVES: Broad-spectrum antibiotics are commonly used for the empiric treatment of acute hematogenous osteomyelitis and often target methicillin-resistant Staphylococcus aureus (MRSA) with medication-associated risk and unknown treatment benefit. We aimed to compare clinical outcomes among patients with osteomyelitis who did and did not receive initial antibiotics used to target MRSA. METHODS: A retrospective cohort study of 974 hospitalized children 2 to 18 years old using the Pediatric Health Information System database, augmented with clinical data. Rates of hospital readmission, repeat MRI and 72-hour improvement in inflammatory markers were compared between treatment groups. RESULTS: Repeat MRI within 7 and 180 days was more frequent among patients who received initial MRSA coverage versus methicillin-sensitive S aureus (MSSA)-only coverage (8.6% vs 4.1% within 7 days [P = .02] and 12% vs 5.8% within 180 days [P < .01], respectively). Ninety- and 180-day hospital readmission rates were similar between coverage groups (9.0% vs 8.7% [P = .87] and 10.9% vs 11.2% [P = .92], respectively). Patients with MRSA- and MSSA-only coverage had similar rates of 72-hour improvement in C-reactive protein values, but patients with MRSA coverage had a lower rate of 72-hour white blood cell count normalization compared with patients with MSSA-only coverage (4.2% vs 16.4%; P = .02). CONCLUSIONS: In this study of children hospitalized with acute hematogenous osteomyelitis, early antibiotic treatment used to target MRSA was associated with a higher rate of repeat MRI compared with early antibiotic treatment used to target MSSA but not MRSA. Hospital readmission rates were similar for both treatment groups.


Assuntos
Antibacterianos/uso terapêutico , Imageamento por Ressonância Magnética , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Osteomielite/tratamento farmacológico , Infecções Estafilocócicas/tratamento farmacológico , Doença Aguda , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Osteomielite/diagnóstico , Osteomielite/microbiologia , Guias de Prática Clínica como Assunto , Estudos Retrospectivos , Infecções Estafilocócicas/diagnóstico , Infecções Estafilocócicas/microbiologia
10.
J Hosp Med ; 13(4): 236-242, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29394301

RESUMO

BACKGROUND: Many hospitals are considering contacting hospitalized patients soon after discharge to help with issues that arise. OBJECTIVE: To (1) describe the prevalence of contactidentified postdischarge issues (PDI) and (2) assess characteristics of children with the highest likelihood of having a PDI. DESIGN, SETTING, PATIENTS: A retrospective analysis of hospital-initiated follow-up contact for 12,986 children discharged from January 2012 to July 2015 from 4 US children's hospitals. Contact was made within 14 days of discharge by hospital staff via telephone call, text message, or e-mail. Standardized questions were asked about issues with medications, appointments, and other PDIs. For each hospital, patient characteristics were compared with the likelihood of PDI by using logistic regression. RESULTS: Median (interquartile range) age of children at admission was 4.0 years (0-11); 59.9% were nonHispanic white, and 51.0% used Medicaid. The most common reasons for admission were bronchiolitis (6.3%), pneumonia (6.2%), asthma (5.1%), and seizure (4.9%). Twenty-five percent of hospitalized children (n=3263) reported a PDI at contact (hospital range: 16.0%-62.8%). Most (76.3%) PDIs were related to follow-up appointments (eg, difficulty getting one); 20.8% of PDIs were related to medications (eg, problems filling a prescription). Patient characteristics associated with the likelihood of PDI varied across hospitals. Older age (age 10-18 years vs <1 year) was significantly (P<.001) associated with an increased likelihood of PDI in 3 of 4 hospitals. CONCLUSIONS: PDIs were identified often through hospital-initiated follow-up contact. Most PDIs were related to appointments. Hospitals caring for children may find this information useful as they strive to optimize their processes for follow-up contact after discharge.


Assuntos
Assistência ao Convalescente/métodos , Hospitalização , Hospitais Pediátricos , Alta do Paciente , Bronquiolite/diagnóstico , Bronquiolite/tratamento farmacológico , Pré-Escolar , Feminino , Humanos , Masculino , Pneumonia/diagnóstico , Pneumonia/tratamento farmacológico , Estudos Retrospectivos , Estados Unidos
11.
JAMA Pediatr ; 168(10): 955-62; quiz 965-6, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25155156

RESUMO

To our knowledge, no widely used pediatric standards for hospital discharge care exist, despite nearly 10 000 pediatric discharges per day in the United States. This lack of standards undermines the quality of pediatric hospital discharge, hinders quality-improvement efforts, and adversely affects the health and well-being of children and their families after they leave the hospital. In this article, we first review guidance regarding the discharge process for adult patients, including federal law within the Social Security Act that outlines standards for hospital discharge; a variety of toolkits that aim to improve discharge care; and the research evidence that supports the discharge process. We then outline a framework within which to organize the diverse activities that constitute discharge care to be executed throughout the hospitalization of a child from admission to the actual discharge. In the framework, we describe processes to (1) initiate pediatric discharge care, (2) develop discharge care plans, (3) monitor discharge progress, and (4) finalize discharge. We contextualize these processes with a clinical case of a child undergoing hospital discharge. Use of this narrative review will help pediatric health care professionals (eg, nurses, social workers, and physicians) move forward to better understand what works and what does not during hospital discharge for children, while steadily improving their quality of care and health outcomes.


Assuntos
Cuidado da Criança/normas , Hospitais Pediátricos/normas , Alta do Paciente/normas , Assistência ao Convalescente/métodos , Criança , Cuidado da Criança/legislação & jurisprudência , Atenção à Saúde/normas , Objetivos , Educação em Saúde , Hospitais Pediátricos/legislação & jurisprudência , Humanos , Prontuários Médicos , Avaliação das Necessidades , Planejamento de Assistência ao Paciente/legislação & jurisprudência , Planejamento de Assistência ao Paciente/organização & administração , Equipe de Assistência ao Paciente/organização & administração , Alta do Paciente/legislação & jurisprudência
12.
PLoS One ; 9(5): e96862, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24837969

RESUMO

The importance of bone morphogenetic protein 2 (BMP2) in the skeleton is well known. BMP2 is expressed in a variety of tissues during development, growth and healing. In this study we sought to better identify the role of tissue-specific BMP2 during post-natal growth and to determine if BMP2 knockout affects the ability of terminally differentiated cells to create high quality bone material. We targeted BMP2 knockout to two differentiated cell types known to express BMP2 during growth and healing, early-stage osteoblasts and their progeny (osterix promoted Cre) and vascular endothelial cells (vascular-endothelial-cadherin promoted Cre). Our objectives were to assess post-natal bone growth, structure and strength. We hypothesized that removal of BMP2 from osteogenic and vascular cells (separately) would result in smaller skeletons with inferior bone material properties. At 12 and 24 weeks of age the osteoblast knockout of BMP2 reduced body weight by 20%, but the vascular knockout had no effect. Analysis of bone in the tibia revealed reductions in cortical and cancellous bone size and volume in the osteoblast knockout, but not in the vascular endothelial knockout. Furthermore, forelimb strength testing revealed a 30% reduction in ultimate force at both 12 and 24 weeks in the osteoblast knockout of BMP2, but no change in the vascular endothelial knockout. Moreover, mechanical strength testing of femurs from osteoblast knockout mice demonstrated an increased Young's modulus (greater than 35%) but decreased post-yield displacement (greater than 50%) at both 12 and 24 weeks of age. In summary, the osteoblast knockout of BMP2 reduced bone size and altered mechanical properties at the whole-bone and material levels. Osteoblast-derived BMP2 has an important role in post-natal skeletal growth, structure and strength, while vascular endothelial-derived BMP2 does not.


Assuntos
Desenvolvimento Ósseo/fisiologia , Proteína Morfogenética Óssea 2/metabolismo , Osso e Ossos/anatomia & histologia , Osteoblastos/metabolismo , Osteócitos/metabolismo , Fatores Etários , Análise de Variância , Animais , Fenômenos Biomecânicos , Desenvolvimento Ósseo/genética , Proteína Morfogenética Óssea 2/genética , Osso e Ossos/metabolismo , Células Endoteliais/metabolismo , Camundongos , Camundongos Knockout , Análise Espectral Raman , Microtomografia por Raio-X
13.
Bonekey Osteovision ; 12012 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-23505338

RESUMO

Bone responds to supraphysiological mechanical loads by increasing bone formation. Depending on the applied strain magnitude (and other loading parameters) the response can be either adaptive (mostly lamellar bone) or injury (mostly woven bone). Seminal studies of Hert, Lanyon, and Rubin originally established the basic "rules" of bone mechanosensitivity. These were reinforced by subsequent studies using non-invasive rodent loading models, most notably by Turner et al. More recent work with these models have been able to explore the structural, transcriptional, and molecular mechanisms which distinguish the two responses (lamellar vs. woven). Wnt/Lrp signaling has emerged as a key mechanoresponsive pathway for lamellar bone. However, there is still much to study with regard to effects of ageing, osteocytes, other signaling pathways, and the molecular regulation that modulates lamellar vs. woven bone formation. This review summarizes not only the historical findings but also the current data for these topics.

14.
J Biomech ; 44(10): 1954-9, 2011 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-21632057

RESUMO

The mechanical properties of periosteum are not well characterized. An understanding of these properties is critical to predict the environment of pluripotent and osteochondroprogenitor cells that reside within the periosteum and that have been shown recently to exhibit a remarkably rapid capacity to generate bone de novo. Furthermore, the effects of cryopreservation on periosteal mechanical properties are currently unknown. We hypothesized that the periosteum is pre-stressed in situ and that the periosteum exhibits anisotropic material properties, e.g. the elastic modulus of the periosteum depends significantly on the direction of loading. We measured the change in area, axial length, and circumferential length of anterior, posterior, medial, and lateral fresh periosteal samples removed from underlying bone (t=0-16 h) as well as the average strain in axially and circumferentially oriented anterior periosteal samples subjected to tensile strain (0.004 mm/s) until failure. The elastic modulus was calculated from the resulting stress-strain curves. Tensile testing was repeated with axially aligned samples that had been slowly cryopreserved for comparison to fresh samples. Periosteal samples from all aspects shrank 44-54%, 33-47%, and 9-19% in area, axial length, and circumferential length, respectively. At any given time, the periosteum shrank significantly more in the axial direction than the circumferential direction. Tensile testing showed that the periosteum is highly anisotropic. When loaded axially, a compliant toe region of the stress-strain curve (1.93±0.14 MPa) is followed by a stiffer region until failure (25.67±6.87 MPa). When loaded circumferentially, no toe region is observable and the periosteum remained compliant until failure (4.41±1.21 MPa). Cryopreservation had no significant effect on the elastic modulus of the periosteum. As the periosteum serves as the bounding envelope of the femur, anisotropy in periosteal properties may play a key role in modulating bone growth, healing and adaptation, in health, disease, and trauma.


Assuntos
Criopreservação/métodos , Fêmur/fisiologia , Periósteo/fisiologia , Animais , Anisotropia , Fenômenos Biomecânicos , Osso e Ossos , Elasticidade , Modelos Animais , Modelos Estatísticos , Ovinos , Estresse Mecânico , Resistência à Tração
15.
Ann Biomed Eng ; 39(5): 1570-81, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21271290

RESUMO

In an ovine femur model, proliferative woven bone fills critically sized defects enveloped by periosteum within 2 weeks of treatment with the one-stage bone-transport surgery. We hypothesize that mechanical loading modulates this process. Using high-definition optical strain measurements we determined prevailing periosteal strains for normal and surgically treated ovine femora subjected ex vivo to compressive loads simulating in vivo stance shifting (n = 3 per group, normal vs. treated). We determined spatial distribution of calcein green, a label for bone apposition in first the 2 weeks after surgery, in 15°, 30°, and 45° sectors of histological cross sections through the middle of the defect zone (n = 6 bones, three to four sections per bone). Finally, we correlated early bone formation to either the maximal periosteal strain or the net change in maximal periosteal strain. We found that treatment with the one-stage bone-transport surgery profoundly changes the mechanical environment of cells within the periosteum during stance shift loading. The pattern of early bone formation is repeatable within and between animals and relates significantly to the actual strain magnitude prevailing in the periosteum during stance shift loading. Interestingly, early bone apposition after the surgery correlates well to the maximal net change in strain (above circa 2000-3000 µÎµ, in tension or compression) rather than strain magnitude per se, providing further evidence that changes in cell shape may drive mechanoadaptation by progenitor cells. These important insights regarding mechanobiological factors that enhance rapid bone generation in critically sized defects can be translated to the tissue and organ scale, providing a basis for the development of best practices for clinical implementation and the definition of movement protocols to enhance the regenerative effect.


Assuntos
Regeneração Óssea , Fêmur/lesões , Fêmur/metabolismo , Fêmur/fisiopatologia , Periósteo/metabolismo , Periósteo/fisiopatologia , Animais , Fêmur/patologia , Fêmur/cirurgia , Osteogênese , Periósteo/patologia , Periósteo/cirurgia , Ovinos , Suporte de Carga
16.
J Biomech ; 44(6): 1205-8, 2011 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-21353676

RESUMO

Recent studies show that minor and major centroidal axes (CA) of long bone cross sections provide valuable predictions of prevailing loading patterns in age and treatment matched cohorts of animals. Furthermore, using CA, we recently showed that the degree of mineralization and area of woven bone laid down in the first two weeks after creation of a critical sized bone defect relate inversely and correlate significantly to loading patterns. Here, we aim to determine how closely independent measures of the spatial distribution of bone apposition determined using the major and minor CA as reference points correlate to those using anatomically defined axes as reference points. In histological sections from the previous study, we found no statistically significant difference between the anatomical and centroidal axes with respect to the centroid location or axis rotation, but there is a significant albeit small difference in the average distance between centroids. Outcome measures calculated in areas of bone defined by 15°, 30°, 45°, 60°, or 90° sectors when using the CA differ less than 5% from those calculated using anatomical axes as reference points. Hence, the major and minor CA provide objective reference points for comparison of mechanobiological outcome measures between animals in matched cohorts. Calculation of major and minor CA is automated, which reduces the potential for observer bias. A major advantage of using the major and minor CA as reference points is that it allows for direct relation of outcome measures to loading patterns in age and treatment matched cohorts, ultimately providing a tool to test mechanobiological hypotheses on histological cross sections of bone.


Assuntos
Regeneração Óssea , Fêmur/lesões , Fêmur/patologia , Fêmur/fisiopatologia , Modelos Biológicos , Animais , Histocitoquímica , Humanos , Ovinos
17.
J Mech Behav Biomed Mater ; 4(6): 829-40, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21616464

RESUMO

The link between mechanics and biology in the generation and the adaptation of bone has been studied for more than a century in the context of skeletal development and fracture healing. However, the interplay between mechanics and biology in de novo generation of bone in postnatal defects as well as healing of morcellized bone graft or massive cortical bone autografts is less well understood. To address this, here we integrate insights from our previously published studies describing the mechanobiology on both de novo bone generation and graft healing in a common ovine femoral defect model. Studying these effects in a common experimental model provides a unique opportunity to elucidate factors conducive to harnessing the regenerative power of the periosteum, and ultimately, to provide mechanistic insights into the multiscale mechanobiology of bone generation, remodeling and adaptation. Taken together, the studies indicate that, as long as adequate, directional transport of cells and molecules can be insured (e.g. with periosteum in situ or a delivery device), biological factors intrinsic to the periosteum suffice to bridge critical sized bone defects, even in the absence of a patent blood supply. Furthermore, mechanical stimuli are crucial for the success of periosteal bone generation and bone graft healing. Interestingly, areas of highest periosteal strain around defects correlate with greatest amounts albeit not greatest mineralization of newly generated bone. This may indicate a role for convection enhanced transport of cells and molecules in modulation of tissue generation by pluripotent cells that ingress into the defect center, away from the periosteum and toward the surface of the intramedullary nail that fills the medullary cavity. These insights bring us much closer to understanding the mechanobiological environment and stimuli that stimulate the proliferation and differentiation of periosteum-derived progenitor cells and ultimately drive the generation of new bone tissue. Furthermore, these insights provide a foundation to create virtual predictive computational models of bone mechanophysiology, to develop cell seeding protocols for scale up and manufacture of engineered tissues, to optimize surgical procedures, and to develop post-surgical therapies with the ultimate goal of achieving the best possible healing outcomes for treatment and/or reconstruction of postnatal bone defects.


Assuntos
Adaptação Fisiológica , Biologia/métodos , Remodelação Óssea , Engenharia/métodos , Fêmur/fisiologia , Fêmur/transplante , Osteogênese , Animais , Fêmur/citologia , Humanos , Modelos Animais , Ovinos , Transplante Autólogo
18.
J Hosp Med ; 3(3): 263-70, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18570324

RESUMO

Pneumonia with associated complex pleural disease is a cause of significant morbidity among hospitalized children. The management of this patient population continues to be a challenge and varies even among single institutions. The article presented here reviews the management goals for pediatric patients hospitalized with complex parapneumonic effusions and provides updated summaries of both medical and surgical therapies.


Assuntos
Derrame Pleural/diagnóstico , Derrame Pleural/terapia , Pneumonia Bacteriana/complicações , Antibacterianos/uso terapêutico , Criança , Drenagem , Humanos , Derrame Pleural/etiologia
19.
Pediatrics ; 116(3): 603-8, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16140699

RESUMO

OBJECTIVE: To determine the incidence of preventable adverse events (AEs) and near misses (NMs) among infants hospitalized for bronchiolitis at a pediatric tertiary care hospital and the impact of these errors on hospital length of stay (LOS). METHODS: We studied 143 infants with bronchiolitis, ages 0 to 12 months, admitted from December 2002 to April 2003. Using prospective chart review and staff reports, we captured medical errors and AEs. Each event was classified as a (1) preventable AE, (2) nonpreventable AE, (3) intercepted NM, (4) nonintercepted NM, or (5) error with little or no potential for harm. RESULTS: Of 143 patients, 15 (10%) suffered an AE or NM. The incidence of preventable AEs was 10 per 100 admissions. We found a higher incidence of preventable AEs and NMs among critically ill patients (CIPs) compared with non-CIPs (68 vs 5 per 100 admissions, respectively), making the absolute risk of an AE or NM 14 times more likely in CIPs. Mean LOS was significantly longer for CIPs with at least 1 AE (9.1 +/- 8.8 days) than for CIPs without AEs (2.9 +/- 1.5 days). Mean LOS was not significantly different between non-CIPs who did (3.8 +/- 2.6 days) and did not (4.2 +/- 5.0 days) experience an AE. CONCLUSIONS: Preventable AEs occur frequently among patients admitted for bronchiolitis, especially those who are critically ill. CIPs who suffer AEs during their hospitalization have longer hospital LOSs. Future studies should investigate error-prevention strategies with a focus on those patients with severe disease.


Assuntos
Bronquiolite/terapia , Hospitalização , Doença Iatrogênica/epidemiologia , Erros Médicos/estatística & dados numéricos , Bronquiolite/complicações , Estado Terminal , Hospitais Pediátricos , Humanos , Doença Iatrogênica/prevenção & controle , Lactente , Tempo de Internação , Erros Médicos/prevenção & controle
20.
Curr Opin Pediatr ; 15(6): 641-9, 2003 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-14631213

RESUMO

Four areas of pediatric office practice are again reviewed: office laboratory procedures, office economics, parenting and parent education, and urinary tract infection. Screening for celiac disease and the use of rapid antigen testing for extrapharyngeal group A Streptococcus infections are included in office laboratory procedures. Utilization of health care among patients with public insurance, electronic medical records, billing among pediatric residents, and satisfaction surveys are reviewed in office economics. Challenges related to breastfeeding, obesity management and timely immunizations are covered within parenting and parent education. Finally, the use of an augmented urinalysis and a discussion of imaging for first febrile urinary tract infections are included in the area of urinary tract infection.


Assuntos
Atenção à Saúde/economia , Poder Familiar , Pais/educação , Infecções Urinárias/diagnóstico , Aleitamento Materno , Doença Celíaca/diagnóstico , Técnicas de Laboratório Clínico , Humanos , Imunização , Obesidade/terapia , Pediatria/métodos , Infecções Estreptocócicas/diagnóstico , Streptococcus pyogenes
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