RESUMEN
Acute respiratory distress syndrome (ARDS) was first described about 30 years ago. Modern definitions and statements have recently been proposed to describe ARDS accurately, but none is perfect. Diffuse alveolar damage is the basic pathological pattern most commonly observed in ARDS, and the term includes permeability edema. The alveolar epithelium of the alveolar-capillary barrier is clearly a key component requiring repair, given its multipotent functional activity. Lung inflammation and neutrophil accumulation are essential markers of disease in ARDS, and a wide variety of pro- and anti-inflammatory cytokines have been described in the alveolar fluid and blood of patients. These molecules still have to prove their value as diagnostic or prognostic biomarkers of ARDS. Supportive therapy in ARDS improved in the past decade; mechanical ventilation with lung protective strategies and patient positioning are gaining interest, but the indications for corticosteroids for ARDS are still debated. Nitric oxide may have a place in the treatment of one-third of patients. Novel approaches, such as surfactant replacement and liquid ventilation, may further improve supportive therapy. Innovative interventions may be on the horizon in treatments that help to resolve or modulate common pathways of ARDS, such as inflammation (eg, granulocyte-colony stimulating factor) or epithelial repair (eg, keratinocyte growth factor).
Asunto(s)
Factores de Crecimiento de Fibroblastos , Síndrome de Dificultad Respiratoria , Corticoesteroides/uso terapéutico , Biomarcadores/análisis , Barrera Alveolocapilar/fisiología , Broncodilatadores/uso terapéutico , Citocinas/análisis , Citocinas/fisiología , Epitelio/patología , Factor 10 de Crecimiento de Fibroblastos , Factor 7 de Crecimiento de Fibroblastos , Factor Estimulante de Colonias de Granulocitos/uso terapéutico , Sustancias de Crecimiento/uso terapéutico , Humanos , Queratinocitos , Neutrófilos/patología , Óxido Nítrico/uso terapéutico , Permeabilidad , Neumonía/patología , Alveolos Pulmonares/patología , Edema Pulmonar/patología , Surfactantes Pulmonares/uso terapéutico , Respiración Artificial , Síndrome de Dificultad Respiratoria/patología , Síndrome de Dificultad Respiratoria/fisiopatología , Síndrome de Dificultad Respiratoria/terapiaRESUMEN
The Autocontrol Project is concerned with the accessing, processing and communication of high quality information so that a clinical team can make and implement decisions for practice change, and then evaluate if improvement has been achieved. High quality information is used as evidence for change. In this study, we have evaluated how evidence is used by a clinical team to explain an identified problem of inappropriate use of blood gas tests. In an experimental study of the Surgical Intensive Care Unit, video recordings of team meetings of nurses and doctors were undertaken, structured according to a problem-based format. Evidence of current practice patterns derived from the hospital information system, as well as the results of a questionnaire to the unit's staff about knowledge and use of blood gas measurements, were supplied to the participants beforehand. At the second meeting, the output of the first meetings and a summarised analysis of pertinent literature were made available. This second meeting was required to finalise the list of causes of inappropriate blood gas use and propose pragmatic strategies for practice change. The video data of the meetings were coded to analyse the use of evidence, the categories of causes, issues and solutions proposed, and the quality of team interaction. The results indicate that in order to achieve consensus, the team used different types of evidence, including objective evidence of practice patterns, personal experience about direct and indirect organisational influences, and literature-based research evidence of best practice. Furthermore, group dynamics were favoured by the problem-based meeting structure, and a high level of cognitive critiquing between team members was observed. This research suggests that a combination of approaches involving identification of both operational factors (e.g. appropriate access to different types of evidence and meeting structure) and cognitive and behavioural approaches (e.g. ensuring expression of different viewpoints) is needed to support strategic decision-making for practice change in a clinical unit. This combined approach should favourably influence the provision of an effective and efficient evidence support environment for the clinical team.
Asunto(s)
Sistemas de Apoyo a Decisiones Clínicas , Medicina Basada en la Evidencia , Grupo de Atención al Paciente , Análisis de los Gases de la Sangre , Humanos , Pautas de la Práctica en Medicina , Encuestas y Cuestionarios , Grabación de Cinta de VideoRESUMEN
The Autocontrol methodology has been developed in order to support the optimisation of decision-making and the use of resources in the context of a clinical unit. The theoretical basis relates to quality assurance and information systems and is influenced by management and cognitive research in the health domain. The methodology uses population rather than individual decision making and because of its dynamic feedback design promises to have rapid and profound effect on practice. Most importantly the health care professional is the principle user of the Autocontrol system. In this methodology we distinguish three types of evidence necessary for practice change: practice based or internal evidence, best evidence derived from the literature or external evidence concerning the practice in question, and process based evidence on how to optimise the process of practice change. The software used by the system is of the executive decision support type which facilitates interrogation of large databases. The Autocontrol system is designed to interrogate the data of the patient medical record however the latter often lacks data on concomitant resource use and this must be supplemented. This paper reviews the Autocontrol methodology and gives examples from current studies.
Asunto(s)
Toma de Decisiones Asistida por Computador , Sistemas de Registros Médicos Computarizados , Análisis de los Gases de la Sangre/estadística & datos numéricos , Recolección de Datos/métodos , Sistemas de Apoyo a Decisiones Clínicas , Sistemas de Información en Hospital , Humanos , Calidad de la Atención de Salud , Interfaz Usuario-ComputadorAsunto(s)
Infección Hospitalaria , Legionelosis , Enfermedad de los Legionarios , Adulto , Anciano , Anciano de 80 o más Años , Infección Hospitalaria/diagnóstico , Infección Hospitalaria/epidemiología , Diagnóstico Diferencial , Femenino , Humanos , Legionelosis/diagnóstico , Legionelosis/epidemiología , Enfermedad de los Legionarios/diagnóstico , Enfermedad de los Legionarios/epidemiología , Masculino , Persona de Mediana Edad , Quebec/epidemiología , Estudios Retrospectivos , Factores de RiesgoRESUMEN
We report a case of adenine phosphoribosyltransferase deficiency in which the initial presentation was chronic renal failure. Diagnosis was made after infrared microscopy analysis of microcrystalline deposits on a kidney allograft biopsy specimen. This type of presentation is rarely seen, the most frequent manifestation of this disease being urolithiasis. This is the first report of recurrence of the microcrystalline nephritis in a kidney transplant with subsequent loss of allograft function.
Asunto(s)
Adenina Fosforribosiltransferasa/deficiencia , Adenina/análogos & derivados , Fallo Renal Crónico/enzimología , Trasplante de Riñón , Adenina/fisiología , Adulto , Humanos , Fallo Renal Crónico/cirugía , Masculino , RecurrenciaAsunto(s)
Algoritmos , Hemoglobinas/metabolismo , Modelos Químicos , Oxígeno/metabolismo , Oxihemoglobinas/metabolismo , Cálculos , Carboxihemoglobina/metabolismo , Hemoglobinas/química , Humanos , Concentración de Iones de Hidrógeno , Cinética , Ligandos , Oxihemoglobinas/química , Unión Proteica , TermodinámicaAsunto(s)
Lesiones Cardíacas/complicaciones , Pericarditis Constrictiva/etiología , Heridas por Arma de Fuego/complicaciones , Anciano , Ecocardiografía , Lesiones Cardíacas/diagnóstico , Lesiones Cardíacas/diagnóstico por imagen , Humanos , Masculino , Factores de Tiempo , Tomografía Computarizada por Rayos X , Guerra , Heridas por Arma de Fuego/diagnóstico , Heridas por Arma de Fuego/diagnóstico por imagenRESUMEN
A personal computer-based arrhythmia generator has been developed based upon mathematical models of modulated parasystole and the related equations. A system of nonlinear difference equations is used to generate the time series of RR intervals of ECG that contain normal as well as ectopic QRS waves. The ECG waveform is synthesized according to the computed RR interval and the type of QRS wave and output via DA converter in a real-time base. Various types of ECGs with ventricular ectopic beats and those with very long periods were generated by selecting values for a small number of model parameters. This method requires neither large RAM nor external memory for storing a library of arrhythmic ECGs. The theory, hardware design, software implementation on a personal computer, and experimental reconstruction of clinical ECGs based on the model are discussed.
Asunto(s)
Arritmias Cardíacas , Electrocardiografía , Microcomputadores , Modelos Cardiovasculares , Modelos Teóricos , Procesamiento de Señales Asistido por Computador , HumanosRESUMEN
Repeated blood sampling (0.2 ml) in the conscious rat during the course of 10 cardiac index measurements using the Fick procedure did not alter the cardiac index as measured initially (285 ml x min-1 x kg-1). However, oxygen consumption and hematocrit were reduced 7-19% and 4-14%, respectively. Replacement of blood removed during sampling with donor blood prevented these responses, but also led to reduced cardiac index and arterial oxygen content, 22-28% and 10-21%, respectively. In additional studies in anesthetized rats, hemorrhage (25 ml/kg) increased plasma K+ by 29% and reduced plasma Na+ by 3%, suggesting that compensatory fluid replacement originated in cells as well as interstitium. This fluid replacement after blood loss helps sustain normal systemic hemodynamics, but blood loss can produce metabolic alterations that should be taken into account in any biochemical study. Although metabolic alterations can be prevented by replacing lost blood with donor blood, cardiopulmonary function may be adversely affected.
Asunto(s)
Volumen Sanguíneo , Hemodinámica , Oxígeno/sangre , Animales , Presión Sanguínea , Transfusión Sanguínea , Electrólitos/sangre , Femenino , Hemorragia/fisiopatología , Concentración de Iones de Hidrógeno , RatasRESUMEN
Postischemic myocardial edema depresses left ventricular function and coronary perfusion. Pharmacologic cardioplegia is being used increasingly to enhance myocardial protection during cardiac operations. In the present study we varied the colloid osmotic and osmotic pressures and the infusion pressures of four cardioplegic solutions to determine their respective roles in producing or preventing myocardial edema in a nonischemic setting. We found that myocardial edema during potassium cardioplegia (1) is independent of infusion pressures, (2) is caused by isosmotic crystalloid solutions, (3) is worsened by hyposmolar crystalloid solutions, (4) is avoided by the addition of colloid, and (5) is avoided if the solution is made hyperosmotic with the addition of mannitol.
Asunto(s)
Edema Cardíaco/inducido químicamente , Paro Cardíaco Inducido , Insuficiencia Cardíaca/inducido químicamente , Potasio/toxicidad , Animales , Agua Corporal/metabolismo , Perros , Edema Cardíaco/fisiopatología , Enfermedad Iatrogénica , Contracción Miocárdica , Miocardio/metabolismo , Presión Osmótica , Potasio/administración & dosificación , SolucionesRESUMEN
In 14 dogs the determinants of myocardial blood supply and metabolic demands were assessed during cardiopulmonary resuscitation (CPR) and under steady-state conditions in fibrillating hearts on cardiopulmonary bypass. During open chest cardiac massage (nine dogs), coronary diastolic blood pressure and blood flow were low. Vasopressor infusion (methoxamine or epinephrine) raised diastolic pressure from 33 +/- 3 to 55 +/- 3 mm. Hg and increased coronary blood flow (CBF) 124 percent (from 38 +/- 3 to 85 +/- 11 c.c. per 100 Gm. per minute. Comparison of these drugs in fibrillating hearts on cardiopulmonary bypass showed that epinephrine increased the "vigor of fibrillation" (intraventricular balloon pressure rose 24 percent and oxygen uptake increased 42%) but impeded subendocardial flow 53% (endocardial/epicardial flow ratio fell from 0.79 to 0.48). In contrast, methoxamine did not significantly change intraventricular balloon pressure, oxygen uptake, coronary flow, or its distribution. We conclude that augmentation of diastolic pressure with alpha adrenergic drugs during CPR improves coronary perfusion and that inotropic drugs may worsen myocardial ischemia during CPR by raising oxygen demands while simultaneously impeding subendocardial blood supply.
Asunto(s)
Presión Sanguínea/efectos de los fármacos , Circulación Coronaria/efectos de los fármacos , Epinefrina/farmacología , Metoxamina/farmacología , Resucitación , Animales , Perros , Contracción Miocárdica/efectos de los fármacos , Estimulación Química , Resistencia Vascular/efectos de los fármacosRESUMEN
We analyzed the performance of two cohorts of surgical residents: one from "pass/fail" and the other from "graded" medical schools. A performance index indicates that the group from graded schools performed significantly better (P less than 0.001). No resident from a pass/fail institution ranked above the 87th percentile, and this group accounted for 82 per cent of those ranking below the 15th percentile. A residency training program that seeks excellence among its trainees would do well to select preferentially students who apply from medical schools providing a specific class standing as part of the total evaluation of the student. It is suggested that the pass/fail controversy is symbolic of the erosion of standards that inevitably occurs when the university becomes involved in transient sociopolitical turmoil.
Asunto(s)
Educación de Postgrado en Medicina , Evaluación Educacional , Cirugía General/educación , Educación de Postgrado en Medicina/normas , Educación de Pregrado en Medicina/normas , Internado y Residencia , Estados UnidosRESUMEN
A method previously established in the experimental animal for predicting the acute response to either metabolic stress (bicarbonate administration) or respiratory stress(manipulation of oxygenator gas during cardiopulmonary bypass) has been extended to man. The method is based on a single nomogram. The accuracy of the nomogram is demonstrated using data from 13 patients on cardiopulmonary bypass. Similar agreement obtains between the nomogram and data reported by others. The nomogram can be used to estimate the therapeutically required dose of bicarbonate.
Asunto(s)
Desequilibrio Ácido-Base/tratamiento farmacológico , Bicarbonatos/uso terapéutico , Desequilibrio Ácido-Base/fisiopatología , Animales , Dióxido de Carbono/sangre , Puente Cardiopulmonar , Modelos Animales de Enfermedad , Perros , Humanos , Concentración de Iones de Hidrógeno , Modelos Biológicos , RespiraciónAsunto(s)
Anemia/etiología , Edema Cardíaco/etiología , Insuficiencia Cardíaca/etiología , Ventrículos Cardíacos/fisiopatología , Hemodilución/efectos adversos , Manitol/uso terapéutico , Anemia/complicaciones , Animales , Puente Cardiopulmonar , Adaptabilidad , Perros , Edema Cardíaco/complicaciones , Edema Cardíaco/tratamiento farmacológico , Enfermedad Iatrogénica , Concentración Osmolar , PerfusiónRESUMEN
Twenty dogs underwent 1 hour of topical hypothermic arrest; five were untreated, five received methyl prednisolone (30 mg/kg), five received 0.2% procaine, and five received both drugs. Arrest was almost immediate (less than 2 min) with procaine, but was delayed 14 +/- 3 minutes in the other groups. Steroid-treated dogs had the highest post-ischemic left ventricular (LV) blood flows (110 +/- 22 cc/100 g/min) (P less than 0.05). Membrane-stabilizing drugs did not prevent myocardial edema; LV water rose 2% (P less than 0.01) in all groups. Post-ischemic LV compliance was depressed most (55%) in the untreated group, and less after procaine (30%) (P less than 0.05). Postischemic LV performance was depressed 44% (P less than 0.01) in the untreated dogs, and returned to near normal levels with steroid (89% recovery), procaine (97% recovery), and both drugs (95% recovery). We conclude that steroids and/or procaine protect against postischemic myocardial depression but do not prevent myocardial edema. Combining steroids and procaine provide no apparent added benefit, but procaine has the technical advantage of almost immediate cardioplegia.