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1.
Sensors (Basel) ; 20(2)2020 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-31947518

RESUMO

In this special issue of Sensors, seven peer-reviewed manuscripts appear on the topic of ultrasonic transducer design and operation in harsh environments: elevated temperature, high gamma and neutron fields, or the presence of chemically aggressive species. Motivations for these research and development projects are strongly focused on nuclear power plant inspections (particularly liquid-sodium cooled reactors), and nondestructive testing of high-temperature piping installations. It is anticipated that we may eventually see extensive use of permanently mounted robust transducers for in-service monitoring of petrochemical plants and power generations stations; quality control in manufacturing plants; and primary and secondary process monitoring in the fabrication of engineering materials.

2.
Elife ; 62017 12 11.
Artigo em Inglês | MEDLINE | ID: mdl-29227246

RESUMO

Object manufacture in insects is typically inherited, and believed to be highly stereotyped. Optimization, the ability to select the functionally best material and modify it appropriately for a specific function, implies flexibility and is usually thought to be incompatible with inherited behaviour. Here, we show that tree-crickets optimize acoustic baffles, objects that are used to increase the effective loudness of mate-attraction calls. We quantified the acoustic efficiency of all baffles within the naturally feasible design space using finite-element modelling and found that design affects efficiency significantly. We tested the baffle-making behaviour of tree crickets in a series of experimental contexts. We found that given the opportunity, tree crickets optimised baffle acoustics; they selected the best sized object and modified it appropriately to make a near optimal baffle. Surprisingly, optimization could be achieved in a single attempt, and is likely to be achieved through an inherited yet highly accurate behavioural heuristic.


Assuntos
Acústica , Gryllidae/fisiologia , Comportamento Sexual Animal , Animais , Árvores/parasitologia
4.
Pediatr Infect Dis J ; 35(9): 987-91, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27195602

RESUMO

BACKGROUND: In developing countries, antiretroviral therapy provides life-saving treatment to HIV-positive women and their children before, during and after birth. However, supply chain challenges such as long distances, medication shortages and nonfacility deliveries often compromise consistent access to prophylactic treatment for at-risk infants. A proposed intervention to address these challenges, often referred to as the "Pratt Pouch," allows for liquid-formulation medications, such as nevirapine (NVP), to be repackaged into single-dose pouches. These pouches are distributed antenatally. METHODS: HIV-positive women at Kilimanjaro Christian Medical Centre in Moshi, Tanzania received 14 pouches each containing a single dose of NVP for prevention of mother-to-child transmission. Women were trained on how to open the pouch and dispense the medication to their infants after delivery. All participating women were asked to return to Kilimanjaro Christian Medical Centre 7-14 days after delivery, where infant blood spots were collected to assess NVP levels. RESULTS: All enrolled women (21/21) administered NVP to their infants within 24 hours of birth. All enrolled infants (22/22) had NVP blood concentrations over 100 ng/mL and exhibited no health concerns attributable to over or under dosing. CONCLUSIONS: The Pratt Pouch intervention provides a clinically appropriate solution for addressing liquid-formulation antiretroviral access challenges in developing countries.


Assuntos
Fármacos Anti-HIV/uso terapêutico , Infecções por HIV/tratamento farmacológico , Infecções por HIV/prevenção & controle , Doenças do Recém-Nascido/tratamento farmacológico , Doenças do Recém-Nascido/prevenção & controle , Transmissão Vertical de Doença Infecciosa/prevenção & controle , Fármacos Anti-HIV/administração & dosagem , Fármacos Anti-HIV/efeitos adversos , Antibioticoprofilaxia , Teste em Amostras de Sangue Seco , Sistemas de Liberação de Medicamentos , Feminino , Infecções por HIV/diagnóstico , Infecções por HIV/transmissão , Humanos , Recém-Nascido , Doenças do Recém-Nascido/diagnóstico , Masculino , Nevirapina/administração & dosagem , Nevirapina/efeitos adversos , Nevirapina/uso terapêutico , Gravidez , Complicações Infecciosas na Gravidez , Kit de Reagentes para Diagnóstico , Tanzânia
5.
Open Biomed Eng J ; 10: 12-8, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27073584

RESUMO

INTRODUCTION: Modern day antiretroviral therapy allows HIV+ pregnant women to lower the likelihood of viral transmission to their infants before, during, and after birth from 20-45% to less than 5%. In developing countries, where non-facility births may outnumber facility births, infant access to safe antiretroviral medication during the critical first three days after birth is often limited. A single-dose, polyethylene pouch ("Pratt Pouch") addresses this challenge by allowing the medication to be distributed to mothers during antenatal care. METHODS: The Pratt Pouch was introduced as part of a one year clinical feasibility study in two districts in Southern Province, Zambia. Participating nurses, community health workers, and pharmacists were trained before implementation. Success in achieving improved antiretroviral medication access was assessed via pre intervention and post intervention survey responses by HIV+ mothers. RESULTS: Access to medication for HIV-exposed infants born outside of a health facility increased from 35% (17/51) before the introduction of the pouch to 94% (15/16) after (p<0.05). A non-significant increase in homebirth rates from 33% (pre intervention cohort) to 50% (post intervention cohort) was observed (p>0.05). Results remained below the national average homebirth rate of 52%. Users reported minimal spillage and a high level of satisfaction with the Pratt Pouch. CONCLUSION: The Pratt Pouch enhances access to infant antiretroviral medication in a rural, non-facility birth setting. Wide scale implementation could have a substantial global impact on HIV transmission rates from mother to child.

6.
Medicine (Baltimore) ; 94(25): e1030, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26107673

RESUMO

Mother-to-child HIV transmission rates remain elevated in countries with high home birth rates. This risk can be dramatically reduced if infants receive antiretroviral (ARV) medication within 24 hours after birth. However, many barriers prevent access to these medications immediately after delivery, for example, there is currently no suitable mechanism to preserve predosed ARVs in the home during the months before birth. In response to this, students of the Duke University developed the Pratt pouch, a foilized polyethylene packet designed to preserve predosed ARVs.This cross-sectional study presents the data from the first clinical trials of the Pratt pouch in Guayaquil, Ecuador.Fourteen HIV-positive mothers and nurses were observed using the pouch to deliver a dose of ARVs to an infant. Weight measurements, time, and notes on spillage were taken at each observation period. Successful usage was quantitatively assessed through the calculation of dosing accuracy based on the volume of liquid medication emptied from the pouch. Additionally, mothers were surveyed after a month of using the device at home to assess their perception of the accuracy, acceptability, and ease of use of the pouch. Used pouches were collected for physical analysis of tearing.Observed users delivered accurate doses (M = 101.1%, standard deviation = 8.2%) in an average time of 2.6 minutes. A total of 2869 used pouches were recovered. No seal failures or failed attempts at opening/delivering the pouches were observed or detected. Forty-three mothers were surveyed. All mothers (100%) reported that they were able to follow their physician's treatment plan, all pouches were received in good condition and the pictorial sheets provided clear instructions.We conclude that the Pratt pouch is a highly accurate and easy-to-use device for delivering liquid oral ARVs to infants and is appropriate for prepackaging ARVs for home use.


Assuntos
Antirretrovirais/administração & dosagem , Formas de Dosagem , Infecções por HIV/prevenção & controle , Transmissão Vertical de Doença Infecciosa/prevenção & controle , Administração Oral , Estudos Transversais , Feminino , Assistência Domiciliar , Humanos , Recém-Nascido , Polietileno , Gravidez
7.
Opt Express ; 22(24): 30346-56, 2014 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-25606963

RESUMO

This study introduces optical feedback interferometry as a simple and effective technique for the two-dimensional visualisation of acoustic fields. We present imaging results for several pressure distributions including those for progressive waves, standing waves, as well as the diffraction and interference patterns of the acoustic waves. The proposed solution has the distinct advantage of extreme optical simplicity and robustness thus opening the way to a low cost acoustic field imaging system based on mass produced laser diodes.


Assuntos
Acústica , Retroalimentação , Imageamento Tridimensional , Interferometria , Fenômenos Ópticos , Processamento de Sinais Assistido por Computador , Ultrassom
8.
J R Soc Interface ; 11(90): 20130857, 2014 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-24196693

RESUMO

Animal ears are exquisitely adapted to capture sound energy and perform signal analysis. Studying the ear of the locust, we show how frequency signal analysis can be performed solely by using the structural features of the tympanum. Incident sound waves generate mechanical vibrational waves that travel across the tympanum. These waves shoal in a tsunami-like fashion, resulting in energy localization that focuses vibrations onto the mechanosensory neurons in a frequency-dependent manner. Using finite element analysis, we demonstrate that two mechanical properties of the locust tympanum, distributed thickness and tension, are necessary and sufficient to generate frequency-dependent energy localization.


Assuntos
Gafanhotos/fisiologia , Som , Estimulação Acústica , Acústica , Animais , Orelha Média/fisiologia , Orelha Média/ultraestrutura , Feminino , Análise de Elementos Finitos , Gafanhotos/ultraestrutura , Audição/fisiologia , Masculino , Propriedades de Superfície , Vibração
9.
Ann Biomed Eng ; 41(9): 1841-50, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23377566

RESUMO

A new product has completed clinical trials in a distant, resource poor hospital using a few dozen prototypes. The data looks great. The novel medical device solves a widely felt problem. The next goal is to integrate the device into the country's healthcare system and spread the device to other countries. But how? In order to be widely used, the device must be manufactured and distributed. One option is to license the intellectual property (IP) to an interested third party, if one can be found. However, it is possible to manage the manufacturing and distribution without licensing. There are at least two common means for manufacturing a novel medical device targeted to resource poor settings: (a) formal (contract) manufacturing and (b) informal (local) manufacturing. There are three primary routes to diffusion of novel medical devices in the developing world: (1) local distributors (2) direct international sales and (3) international donations. Perhaps surprisingly, the least effective mechanism is direct importation through donation. The most successful mechanism, the method used by nearly all working medical devices in resource-poor settings, is the use of contract manufacturing and a local distributor. This article is written for the biomedical innovator and entrepreneur who wishes to make a novel healthcare technology or product available and accessible to healthcare providers and patients in the developing world. There are very few documented cases and little formal research in this area. To this end, this article describes and explores the manufacturing and distribution options in order to provide insights into when and how each can be applied to scale up a novel technology to make a difference in a resource poor setting.


Assuntos
Tecnologia Biomédica , Assistência à Saúde , Custos de Cuidados de Saúde/tendências , Transferência de Tecnologia , Tecnologia Biomédica/economia , Tecnologia Biomédica/legislação & jurisprudência , Tecnologia Biomédica/normas , Tecnologia Biomédica/tendências , Assistência à Saúde/economia , Assistência à Saúde/normas , Assistência à Saúde/tendências , Humanos
10.
Open Biomed Eng J ; 6: 92-7, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23028405

RESUMO

Many children become HIV+ due to mother-to-child transmission, a risk that can be largely eliminated if infants ingest antiretroviral (ARV) medications immediately after birth. As most mothers in Africa deliver at home, the ARV must be provided at their last antenatal visit, sometimes months before birth. No current drug delivery system allows the mother to store the medication at home long enough to be effective. We propose a preserving, foilized, polyethylene pouch to be pre-dosed and sealed by a pharmacist for later delivery to the newborn.Pouches were filled with 0.6 ml of Nevirapine (NVP). Thirty-three pouches were immediately studied to measure the impact of medication handling (oxygen, light, filling and sealing the pouches). The remaining samples were stored for up to one year at three storage conditions (25°C/60%RH, 30°C/65%RH, and 40°C/75%RH). Every two months, moisture loss, preservative concentration, impurity concentrations and NVP concentration were measured. Flora and fauna challenges were conducted.THE POUCH NEARLY ELIMINATED MOISTURE LOSS: pouches lost less than 0.7% of their weight over twelve months. As expected, exposing the medication to light, oxygen, and handling significantly affected the sacrificial preservative concentrations (Propyl paraben dropped 38%, Methyl paraben dropped 12% at time point zero). However, after the initial time point, preservative levels were stable in the package over twelve months under all storage conditions (4.1% average concentration drop), leaving sufficient preservatives to protect the medication. The concentration of NVP changed an average of only 1.3% over all storage conditions and times points (maximum 1.4%).We conclude that the foilized polyethylene pouch can preserve NVP, and perhaps other ARV's, for up to one year.

11.
Lancet ; 380(9840): 507-35, 2012 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-22857974

Assuntos
Anti-Infecciosos/provisão & distribução , Países Desenvolvidos , Países em Desenvolvimento , Saúde Global , Pobreza , Tecnologia , Acidentes de Trânsito/prevenção & controle , Comitês Consultivos , Ambulâncias , Anemia Falciforme/diagnóstico , Fármacos Anti-HIV/economia , Fármacos Anti-HIV/provisão & distribução , Contagem de Linfócito CD4/normas , Contagem de Linfócito CD4/tendências , Doenças Cardiovasculares/prevenção & controle , Mortalidade da Criança/tendências , Pré-Escolar , Características Culturais , Testes Diagnósticos de Rotina , , Saúde Global/normas , Saúde Global/tendências , Infecções por HIV/diagnóstico , Infecções por HIV/imunologia , Infecções por HIV/prevenção & controle , Acesso aos Serviços de Saúde/normas , Acesso aos Serviços de Saúde/tendências , Humanos , Fome , Incubadoras para Lactentes/provisão & distribução , Lactente , Mortalidade Infantil/tendências , Mosquiteiros Tratados com Inseticida , Cobertura do Seguro , Malária/prevenção & controle , Vacinação em Massa/normas , Vacinação em Massa/tendências , Mortalidade Materna/tendências , Saúde Mental/normas , Saúde Mental/tendências , Organizações/normas , Organizações/tendências , Prevenção Primária/normas , Prevenção Primária/tendências , Próteses e Implantes , Parcerias Público-Privadas/tendências , Saúde da População Rural , Segurança , Saneamento/normas , Saneamento/tendências , Tecnologia/normas , Tecnologia/tendências , Medicina Tropical/normas , Medicina Tropical/tendências , Tuberculose/prevenção & controle , Vacinas Virais/economia
12.
Open Biomed Eng J ; 6: 1-4, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22371814

RESUMO

Biphasic defibrillation waveforms are now accepted as being more effective at terminating ventricular fibrillation (VF) than monophasic waveforms. If two phases are better than one, this naturally leads to the hypothesis that additional phases improve efficacy. This study tests the hypothesis by adding one additional phase. We examined the efficacy of 18 different triphasic waveforms simultaneously.We tested the rate of recovery, i.e., successful defibrillation, of 21 guinea pigs (820-1,050 g) using triphasic, monophasic and biphasic defibrillation waveforms. The biphasic and monophasic were control waveforms. VF was electrically induced twenty times per animal and a single defibrillation attempt was made using a test waveform VF episode. Every waveform was adjusted to the energy required to defibrillate that animal 50% of the time, using a biphasic waveform as a control. The success rate of each triphasic waveform was pair-wise compared to the biphasic and monophasic control using the adjusted McNemar statistical test.Of the 18 triphasic waveforms tested, two were significantly poorer than the monophasic control (p<0.05). One was superior to the biphasic waveform (p<0.1), but not statistically so. We concluded that, while adding a phase to a monophasic waveform does improve efficacy, adding an additional phase to a biphasic waveform does not necessarily improve efficacy.

13.
Pacing Clin Electrophysiol ; 34(11): 1582-1583, 2011 11.
Artigo em Inglês | MEDLINE | ID: mdl-21883305
14.
Med Biol Eng Comput ; 49(7): 719-22, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21597999

RESUMO

It is often said that most of the medical equipment in the developing world is broken with estimates ranging up to 96% out of service. But there is little documented evidence to support these statements. We wanted to quantify the amount of medical equipment that was out of service in resource poor health settings and identify possible causes. Inventory reports were analyzed from 1986 to 2010, from hospitals in sixteen countries across four continents. The UN Human Development Index was used to determine which countries should be considered developing nations. Non-medical hospital equipment was excluded. This study examined 112,040 pieces of equipment. An average of 38.3% (42,925, range across countries: 0.83-47%) in developing countries was out of service. The three main causes were lack of training, health technology management, and infrastructure. We hope that the findings will help biomedical engineers with their efforts toward effective designs for the developing world and NGO's with efforts to design effective healthcare interventions.


Assuntos
Países em Desenvolvimento , Falha de Equipamento/estatística & dados numéricos , Equipamentos e Provisões Hospitalares/normas , Cooperação Internacional , Tecnologia Biomédica , Equipamentos e Provisões Hospitalares/estatística & dados numéricos , Humanos , Área Carente de Assistência Médica
15.
Pacing Clin Electrophysiol ; 34(5): 577-83, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21208244

RESUMO

BACKGROUND: A percutaneously placed, totally intravascular defibrillator has been developed that shocks via a right ventricular (RV) single-coil and titanium electrodes in the superior vena cava (SVC) and the inferior vena cava (IVC). This study evaluated the defibrillation threshold (DFT) with this electrode configuration to determine the effect of different biphasic waveform tilts and second-phase durations as well as the contribution of the IVC electrode. METHODS: Eight Bluetick hounds (wt = 30-40 kg) were anesthetized and the RV coil (first-phase anode) was placed in the RV apex. The intravascular defibrillator (PICD®, Model no. IIDM-G, InnerPulse Inc., Research Triangle Park, NC, USA) was positioned such that the titanium electrodes were in the SVC and IVC . Ventricular fibrillation was electrically induced and a Bayesian up-down technique was employed to determine DFT with two configurations: RV to SVC + IVC and RV to SVC. Three waveform tilts (65%, 50%, and 42%) and two second-phase durations (equal to the first phase [balanced] and truncated at 3 ms [unbalanced]) were randomly tested. The source capacitance of the defibrillator was 120 µF for all waveforms. RESULTS: DFT with the IVC electrode was significantly lower than without the IVC electrode for all waveforms tested (527 ± 9.3 V [standard error], 14.5 J vs 591 ± 7.4 V, 18.5 J, P < 0.001). Neither waveform tilt nor second-phase duration significantly changed the DFT. CONCLUSION: In canines, a totally intravascular implantable defibrillator with electrodes in the RV apex, SVC, and IVC had a DFT similar to that of standard nonthoracotomy lead systems. No significant effect was noted with changes in tilt or with balanced or unbalanced waveforms.


Assuntos
Desfibriladores Implantáveis , Cardioversão Elétrica/instrumentação , Veia Cava Inferior , Animais , Teorema de Bayes , Cães , Eletrocardiografia , Eletrodos , Desenho de Equipamento , Processamento de Sinais Assistido por Computador , Titânio
16.
Heart Rhythm ; 8(2): 288-92, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21034853

RESUMO

BACKGROUND: An intravascular, percutaneously placed implantable defibrillator (InnerPulse percutaneous intravascular cardioverter-defibrillator [PICD]) with a right ventricular (RV) single-coil lead and titanium electrodes in the superior vena cava (SVC) and the inferior vena cava (IVC) has been developed. OBJECTIVE: The purpose of this study was to compare defibrillation thresholds (DFTs) of the PICD to those of a conventional implantable cardioverter-defibrillator (ICD) in canines. METHODS: Eight Bluetick hounds were randomized to initial placement of either a PICD or a conventional ICD. For PICD DFTs, a single-coil RV defibrillator lead was placed in the RV apex, and the device was positioned in the venous vasculature with electrodes in the SVC and IVC. With the conventional ICD, an RV lead was placed in the RV apex and an SVC coil was appropriately positioned. The ICD active can (AC) was implanted in a subcutaneous pocket formed in the left anterior chest wall and connected to the lead system. DFT was determined by a three-reversal, step up-down method to estimate the 80% success level. Two configurations were tested for the conventional ICD (#1: RV to SVC+AC; #2: RV to AC). A single configuration (RV to SVC+IVC) was evaluated for the PICD. RESULTS: Mean PICD DFT was 14.8 ± 1.53 (SE) J. Conventional #1 configuration demonstrated mean DFT of 20.2 ± 2.45 J and #2 of 27.5 ± 1.95 J. The PICD had a significantly lower DFT than the better conventional ICD configuration (#1; mean difference 5.4 ± 2.1 J, P <.05, paired t-test, N = 8). CONCLUSION: The new intravascular defibrillator had a significantly lower DFT than the conventional ICD in this canine model.


Assuntos
Desfibriladores Implantáveis , Veia Cava Inferior , Veia Cava Superior , Fibrilação Ventricular/terapia , Animais , Modelos Animais de Doenças , Cães , Eletrocardiografia , Desenho de Equipamento , Segurança de Equipamentos , Distribuição Aleatória , Sensibilidade e Especificidade , Fibrilação Ventricular/diagnóstico
17.
IEEE Eng Med Biol Mag ; 29(2): 37-43, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20659839

RESUMO

Phototherapy is the standard treatment for severe cases of hyperbilirubinemia in newborns. Phototherapy exposes the infants to light in the range of 400-500 nm to isomerize unconjugated bilirubin in the skin. Any light source that produces this wavelength can be used, including the sun (though there is a risk of sunburn), fluorescent or halogen lamps, or, more recently, light-emitting diodes. Despite the well-established efficacy of phototherapy devices and their relative simplicity-being not much more than a floor lamp-phototherapy devices are too expensive for developing world hospitals to purchase, with typical hospital models ranging from US$3,000 to US$5,000. In addition, the resource-poor setting presents a more challenging engineering problem than most. Phototherapy devices are frequently donated to developing world hospitals. However, donated phototherapy devices typically run for no more than a few months once donated and, even then, offer little value to some hospitals. Given this background, we set out to design a phototherapy device specifically for use in the developing world. As a minimum, we knew that it had to have a light source with an extraordinarily long life span and have battery backup so that it could run during frequent power outages. Our design uses LEDs and is powered by a car or motorcycle battery. In this article, we present the full engineering design cycle, staring with needs identification and continuing through several cycles of engineering field trials and results with comments on the differences between the engineering design cycle executed in, and for, the developing world.


Assuntos
Hiperbilirrubinemia Neonatal/terapia , Fototerapia/instrumentação , Fototerapia/métodos , Países em Desenvolvimento , Desenho de Equipamento , Análise de Falha de Equipamento , Humanos , Recém-Nascido
18.
Med Biol Eng Comput ; 48(7): 721-6, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20490939

RESUMO

Much of the laboratory and medical equipment in resource-poor settings is out-of-service. The most commonly cited reasons are (1) a lack of spare parts and (2) a lack of highly trained technicians. However, there is little data to support these hypotheses, or to generate evidence-based solutions to the problem. We studied 2,849 equipment-repair requests (of which 2,529 were out-of-service medical equipment) from 60 resource-poor hospitals located in 11 nations in Africa, Europe, Asia, and Central America. Each piece of equipment was analyzed by an engineer or an engineering student and a repair was attempted using only locally available materials. If the piece was placed back into service, we assumed that the engineer's problem analysis was correct. A total of 1,821 pieces of medical equipment were placed back into service, or 72%, without requiring the use of imported spare parts. Of those pieces repaired, 1,704 were sufficiently documented to determine what knowledge was required to place the equipment back into service. We found that six domains of knowledge were required to accomplish 99% of the repairs: electrical (18%), mechanical (18%), power supply (14%), plumbing (19%), motors (5%), and installation or user training (25%). A further analysis of the domains shows that 66% of the out-of-service equipment was placed back into service using only 107 skills covering basic knowledge in each domain; far less knowledge than that required of a biomedical engineer or biomedical engineering technician. We conclude that a great majority of laboratory and medical equipment can be put back into service without importing spare parts and using only basic knowledge. Capacity building in resource-poor settings should first focus on a limited set of knowledge; a body of knowledge that we call the biomedical technician's assistant (BTA). This data set suggests that a supported BTA could place 66% of the out-of-service laboratory and medical equipment in their hospital back into service.


Assuntos
Técnicas de Laboratório Clínico/instrumentação , Equipamentos e Provisões Hospitalares/normas , Serviço Hospitalar de Engenharia e Manutenção/normas , Área Carente de Assistência Médica , Fortalecimento Institucional , Países em Desenvolvimento , Falha de Equipamento , Reutilização de Equipamento , Equipamentos e Provisões Hospitalares/provisão & distribução , Medicina Baseada em Evidências/métodos , Humanos
19.
Cases J ; 2: 8878, 2009 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-19918350

RESUMO

INTRODUCTION: This is a report of a 56-year-old man who became hypoxic due to an acute right to left shunt after sustaining a myocardial infarction involving the right ventricle. This case provides the opportunity to review several key pathophysiologic concepts in the setting of acute right ventricular infarction. Although the development of an acute right to left shunt is a rare complication of myocardial infarction, it is important to recognize the diagnosis early in order to prevent life threatening or debilitating clinical sequelae that may result from tissue hypoxia and embolic events. Transesophageal echocardiography is the noninvasive study of choice to confirm the diagnosis. Treatment involves optimization of right ventricular function to minimize shunting. However, medical therapy may provide only temporary relief, and closure of the atrial septal defect should be considered if a clinically significant shunt persists. CASE PRESENTATION: A 56-year-old Caucasian man with severe aortic insufficiency presented to the emergency department for evaluation of substernal chest pain. An inferior myocardial infarction was diagnosed by the electrocardiogram and serologic markers. Cardiac catheterization revealed complete occlusion of the right coronary artery as well as a 50-75% stenosis of the left anterior descending artery. Angioplasty of the right coronary artery was performed, but immediate re-occlusion occurred. Subsequently, hypotension and severe hypoxemia developed and persisted despite intubation and mechanical ventilation with 100% oxygen. A significant right-to-left shunt through a patent foramen ovale was diagnosed by contrast transesophageal echocardiogram. Surgical intervention was required and included coronary artery bypass grafting, aortic valve replacement as well as closure of his atrial septal defect. CONCLUSION: A right to left atrial shunt is a rare complication of inferior myocardial infarction with right ventricular infarction. The diagnosis should be considered in the presence of inferior myocardial infarction when hypoxemia persists despite administration of 100% oxygen. Early diagnosis and treatment are critical in order to reduce the risk of embolization and to prevent end-organ damage due to hypoxemia.

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