RESUMEN
INTRODUCTION: Impedance cardiography (IC) derived from morphological analysis of the thoracic impedance signal is now commonly used for noninvasive assessment of cardiac output (CO) at rest and during exercise. However, in Chronic Obstructive Pulmonary Disease (COPD), conflicting findings put its accuracy into question. OBJECTIVES: We therefore compared concurrent CO measurements captured by IC (PhysioFlow: COIC ) and by the indocyanine green dye dilution method (CODD ) in patients with COPD. METHODS: Fifty paired CO measurements were concurrently obtained using the two methods from 10 patients (FEV1 : 50.5 ± 17.5% predicted) at rest and during cycling at 25%, 50%, 75% and 100% peak work rate. RESULTS: From rest to peak exercise COIC and CODD were strongly correlated (r = 0.986, P < 0.001). The mean absolute and percentage differences between COIC and CODD were 1.08 L/min (limits of agreement (LoA): 0.05-2.11 L/min) and 18 ± 2%, respectively, with IC yielding systematically higher values. Bland-Altman analysis indicated that during exercise only 7 of the 50 paired measurements differed by more than 20%. When data were expressed as changes from rest, correlations and agreement between the two methods remained strong over the entire exercise range (r = 0.974, P < 0.001, with no significant difference: 0.19 L/min; LoA: -0.76 to 1.15 L/min). Oxygen uptake (VO2 ) and CODD were linearly related: r = 0.893 (P < 0.001), CODD = 5.94 × VO2 + 2.27 L/min. Similar results were obtained for VO2 and COIC (r = 0.885, P < 0.001, COIC = 6.00 × VO2 + 3.30 L/min). CONCLUSIONS: These findings suggest that IC provides an acceptable CO measurement from rest to peak cycling exercise in patients with COPD.
Asunto(s)
Gasto Cardíaco/fisiología , Cardiografía de Impedancia/métodos , Prueba de Esfuerzo/métodos , Enfermedad Pulmonar Obstructiva Crónica/fisiopatología , Anciano , Técnica de Dilución de Colorante/instrumentación , Femenino , Humanos , Masculino , Persona de Mediana Edad , Consumo de Oxígeno/fisiologíaRESUMEN
Quantitative evaluation of minimal polynucleotide concentrations has become a critical analysis among a myriad of applications found in molecular diagnostic technology. Development of high-throughput, nonenzymatic assays that are sensitive, quantitative and yet feasible for point-of-care testing are thus beneficial for routine implementation. Here, we develop a nonenzymatic method for quantifying surface concentrations of labeled DNA targets by coupling regulated amounts of polymer growth to complementary biomolecular binding on array-based biochips. Polymer film thickness measurements in the 20-220 nm range vary logarithmically with labeled DNA surface concentrations over two orders of magnitude with a lower limit of quantitation at 60 molecules/microm(2) (approximately 10(6) target molecules). In an effort to develop this amplification method towards compatibility with fluorescence-based methods of characterization, incorporation of fluorescent nanoparticles into the polymer films is also evaluated. The resulting gains in fluorescent signal enable quantification using detection instrumentation amenable to point-of-care settings.
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ADN/análisis , Eosina Amarillenta-(YS)/análogos & derivados , Análisis de Secuencia por Matrices de Oligonucleótidos/métodos , Oligonucleótidos/análisis , Estreptavidina/química , Unión Competitiva , Biotina/química , ADN/química , Técnica de Dilución de Colorante/instrumentación , Eosina Amarillenta-(YS)/química , Colorantes Fluorescentes/química , Cinética , Microscopía Fluorescente , Nanopartículas/química , Oligonucleótidos/química , Propiedades de SuperficieRESUMEN
BACKGROUND AND OBJECTIVE: The transcerebral double-indicator dilution technique is a recently developed method to measure global cerebral blood flow at bedside. It is based on bolus injection of ice-cold indocyanine green dye and simultaneous recording of resulting thermo- and dye-dilution curves in the aorta and the jugular bulb. However, with this method 40 mL of ice-cold solution is administered as a bolus. Therefore, this prospective clinical study was performed to elucidate the effects of repeated administration of indicator on absolute blood temperature and on cerebral blood flow and metabolism. METHODS: The investigation was performed in nine male patients scheduled for elective coronary artery bypass grafting. Absolute blood temperature was measured in the jugular bulb and in the aorta before and after repeated measurements using the transcerebral double-indicator dilution technique. RESULTS: During the investigated time course, the blood temperature in the jugular bulb, compared to the aorta, was significantly higher with a mean difference of 0.21 degrees C. The administration of an ice-cold bolus reduced the mean blood temperature by 0.06 degrees C in the jugular bulb as well as in the aorta. After the transcerebral double-indicator dilution measurements a temperature recovery to baseline conditions was not observed during the investigated time period. Cerebral blood flow and cerebral metabolism did not change during the investigated time period. CONCLUSIONS: Repeated measurements with the transcerebral double-indicator dilution technique do not affect absolute jugular bulb blood temperatures negatively. Global cerebral blood flow and metabolism measurements remain unaltered. However, accuracy and resolution of this technique is not high enough to detect the effect of minor changes of physiological variables.
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Fenómenos Fisiológicos Sanguíneos , Temperatura Corporal/fisiología , Circulación Cerebrovascular/fisiología , Técnicas de Dilución del Indicador , Anciano , Análisis de Varianza , Aorta , Encéfalo/metabolismo , Cateterismo Venoso Central , Cateterismo Periférico , Colorantes , Puente de Arteria Coronaria , Técnica de Dilución de Colorante/instrumentación , Humanos , Verde de Indocianina , Venas Yugulares , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Termodilución/instrumentaciónRESUMEN
We report the development of a new subdural probe for combined intracranial pressure (ICP) and cerebral blood flow (CBF) monitoring with near infrared spectroscopy (NIRS) and indocyanine green (ICG) dye dilution. For NIRS a conventional subdural ICP monitoring probe was supplied with two fiber bundles and 90-degree prisms. Injections of 25 mg ICG were performed. Regional values for the mean transit time of ICG (rmtt(ICG)), cerebral blood flow (rCBF) and cerebral blood volume (rCBV) were calculated. With prototypes of the probe in two patients with intracerebral haemorrhage 18 comparative measurements obtained simultaneously with conventional NIRS (optodes placed on the skin) and the subdural NIRS probe were performed. The new subdural NIRS probe allows combined monitoring of ICP and cerebral hemodynamics in the brain directly, without the influence of extracerebral tissue.
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Velocidad del Flujo Sanguíneo/fisiología , Encéfalo/irrigación sanguínea , Técnica de Dilución de Colorante/instrumentación , Electrodos Implantados , Urgencias Médicas , Verde de Indocianina , Hemorragias Intracraneales/cirugía , Presión Intracraneal/fisiología , Microcirugia , Monitoreo Intraoperatorio/instrumentación , Espectroscopía Infrarroja Corta/instrumentación , Presión Sanguínea/fisiología , Cuidados Críticos , Diseño de Equipo , Hematoma Subdural/cirugía , Humanos , Flujo Sanguíneo Regional/fisiología , Espacio Subdural , Evaluación de la Tecnología Biomédica , TrepanaciónRESUMEN
OBJECTIVE: To compare the results of cardiac output measurements obtained by lithium dilution and transpulmonary thermodilution in paediatric patients. DESIGN: A prospective study. SETTING: Paediatric intensive care unit in a university teaching hospital. PATIENTS: Twenty patients (age 5 days-9 years; weight 2.6-28.2 kg) were studied. INTERVENTIONS: Between two and four comparisons of lithium dilution cardiac output (LiDCO) and transpulmonary thermodilution (TPCO) were made in each patient. MEASUREMENTS AND RESULTS: Results from three patients were excluded: in one patient there was an unsuspected right-to-left shunt, in two patients there was a problem with blood sampling through the lithium sensor. There were 48 comparisons of LiDCO and TPCO in the remaining 17 patients over a range of 0.4-6 l/min. The mean of the differences (LiDCO-TPCO) was -0.1 +/- 0.3 (SD) l/min. Linear regression analysis gave LiDCO = 0.11 + 0.90 x TPCO l/min (r2 = 0.96). There were no adverse effects in any patient. CONCLUSIONS: These results suggest that the LiDCO method can be used to provide safe and accurate measurement of cardiac output in paediatric patients. The method is simple and quick to perform, requiring only arterial and venous catheters, which will already have been inserted for other reasons in these patients.
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Gasto Cardíaco , Técnica de Dilución de Colorante , Arteria Femoral , Arteria Ilíaca , Cloruro de Litio , Termodilución/métodos , Factores de Edad , Peso Corporal , Cateterismo Venoso Central/instrumentación , Cateterismo Venoso Central/métodos , Técnica de Dilución de Colorante/instrumentación , Estudios de Factibilidad , Humanos , Recién Nacido , Unidades de Cuidado Intensivo Pediátrico , Cuidado Intensivo Neonatal/métodos , Modelos Lineales , Cloruro de Litio/sangre , Cloruro de Litio/farmacocinética , Estudios Prospectivos , Arteria Pulmonar , Termodilución/instrumentación , Factores de TiempoRESUMEN
OBJECTIVES: We studied the correlation between invasive (aortic fiberoptic) and noninvasive (transcutaneous sensor) measurements of indocyanine green (ICG) plasma disappearance rate (PDR) in critically ill patients. DESIGN AND SETTING: Prospective clinical study in a surgical intensive care unit of a university hospital. PATIENTS: 16 critically ill patients with adult respiratory distress syndrome (n = 8), sepsis/septic shock (n = 6), subarachnoid hemorrhage (n = 1), or severe head injury (n = 1). MEASUREMENTS AND RESULTS: We analyzed 16 pairs of simultaneous ICG PDR measurements. All patients were deeply sedated and mechanically ventilated. Each patient received a 4-F aortic catheter with an integrated fiberoptic and thermistor connected to a computer system for automatic calculation of invasive ICG PDR (PDRINV). An ICG sensor was also attached to the nose wing and connected to a DDG2001 analyzer for noninvasive measurement (PDRNINV). Linear regression analysis revealed PDRNINV = 0.98 PDRINV +0.11%/min (r = 0.94, p < 0.0001) with a mean bias of 0.2 +/- 2.0%/min. CONCLUSION: Noninvasive measurements of ICG PDR are very highly correlated with values derived from an invasive fiberoptic-based reference technique.
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Monitoreo de Gas Sanguíneo Transcutáneo/métodos , Colorantes/farmacocinética , Traumatismos Craneocerebrales/metabolismo , Técnica de Dilución de Colorante , Hemodinámica , Verde de Indocianina/farmacocinética , Monitoreo Fisiológico/métodos , Respiración Artificial/efectos adversos , Síndrome de Dificultad Respiratoria/metabolismo , Sepsis/metabolismo , Hemorragia Subaracnoidea/metabolismo , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Sesgo , Monitoreo de Gas Sanguíneo Transcutáneo/instrumentación , Traumatismos Craneocerebrales/fisiopatología , Traumatismos Craneocerebrales/terapia , Enfermedad Crítica , Técnica de Dilución de Colorante/instrumentación , Femenino , Humanos , Modelos Lineales , Pruebas de Función Hepática , Masculino , Tasa de Depuración Metabólica , Persona de Mediana Edad , Monitoreo Fisiológico/instrumentación , Estudios Prospectivos , Síndrome de Dificultad Respiratoria/fisiopatología , Síndrome de Dificultad Respiratoria/terapia , Sepsis/fisiopatología , Sepsis/terapia , Hemorragia Subaracnoidea/fisiopatología , Hemorragia Subaracnoidea/terapiaRESUMEN
OBJECTIVES: To evaluate the effect of the stable prostacyclin analogue iloprost on the plasma disappearance rate of indocyanine green (PDR) in patients with septic shock. DESIGN AND SETTING: A prospective clinical study in a university hospital intensive care unit. PATIENTS AND INTERVENTIONS: 20 patients in septic shock. Patients received iloprost infusion (1 ng/kg per minute) for 24 h. MEASUREMENTS AND RESULTS: PDR was determined by a femoral arterial fiberoptic catheter before, 1, 6, and 24 h after start and 1 h after end of iloprost infusion. PDR increased significantly 24 h after start of iloprost infusion (baseline: 13.9 +/- 1.7% vs. 18.6 +/- 2.2%/min) and decreased 1 h after end of infusion (13.7 +/- 1.7%/min; p < 0.002). There was no change in pHi, cardiac index, mean arterial pressure, heart rate, central venous pressure, or intrathoracic blood volume index. CONCLUSION: Administration of the stable prostacyclin analogue iloprost significantly increases PDR, indicating improvement in liver function.
Asunto(s)
Colorantes/farmacocinética , Epoprostenol/análogos & derivados , Iloprost/uso terapéutico , Verde de Indocianina/farmacocinética , Choque Séptico/tratamiento farmacológico , Choque Séptico/metabolismo , Vasodilatadores/uso terapéutico , Adulto , Anciano , Monitoreo de Drogas/instrumentación , Monitoreo de Drogas/métodos , Técnica de Dilución de Colorante/instrumentación , Femenino , Hemodinámica , Humanos , Iloprost/farmacología , Infusiones Intravenosas , Hígado/metabolismo , Hígado/fisiopatología , Pruebas de Función Hepática , Masculino , Tasa de Depuración Metabólica/efectos de los fármacos , Persona de Mediana Edad , Estudios Prospectivos , Choque Séptico/fisiopatología , Vasodilatadores/farmacologíaRESUMEN
OBJECTIVE: To test the practicability of a new double indicator dilution method for bedside monitoring of cerebral blood flow (CBF) and to assess the clinical value of CBF monitoring as a prognostic tool for outcome and in therapy of elevated intracranial pressure (ICP) in patients with acute hemispheric stroke. DESIGN: Prospective study. Clinical evaluation of a new method. SETTING: Neurological intensive care unit of a university hospital. PATIENTS: Ten patients with acute complete middle cerebral artery territory- or hemispheric infarctions. INTERVENTIONS: Two combined fiberoptic thermistor catheters were placed in the right jugular bulb and in the thoracic aorta. Central venous injections of ice-cold indocyanine green dye were performed. CBF was estimated by calculating the mean transit times of the cold bolus and dye. MEASUREMENTS AND MAIN RESULTS: A total of 104 reproducible CBF measurements were obtained. No complications associated with the method were observed. Twelve pairs of measurements were performed within 30 mins with unchanged clinical conditions. The standard deviation of repeated measurements was 2.7 mL/100 g/min; the interrater reliability was between 0.95 and 0.99. The median CBF in patients who died (n = 4) was lower (27 mL/100g/min) than in those who survived (n = 6) (45 mL/100g/ min). Patients who died more frequently had low CBF values of <30 mL/100g/min (22 of 38; 58%) than patients who survived (10 of 54; 19%). A total of 37 CBF measurements were done during ICP elevation of >20 mm Hg. In patients who survived, ICP elevations were only associated with low CBF values in 5 of 26 events; whereas in patients who died, ICP elevations were associated with low CBF values in 8 of 11 events. CONCLUSIONS: The new double indicator dilution technique may be suitable for serial bedside CBF measurement. It is easy to perform and can be rapidly repeated in the ICU environment. Validation of the method by comparison with standard methods is needed. The preliminary data indicate that bedside monitoring of CBF may give prognostic information for outcome and may guide therapy of elevated ICP in patients with malignant hemispheric infarction.
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Circulación Cerebrovascular , Técnica de Dilución de Colorante , Monitoreo Fisiológico/métodos , Sistemas de Atención de Punto , Accidente Cerebrovascular/diagnóstico , Accidente Cerebrovascular/fisiopatología , Termodilución/métodos , Enfermedad Aguda , Adulto , Anciano , Velocidad del Flujo Sanguíneo , Colorantes , Cuidados Críticos , Técnica de Dilución de Colorante/instrumentación , Femenino , Humanos , Verde de Indocianina , Hipertensión Intracraneal/etiología , Hipertensión Intracraneal/terapia , Masculino , Persona de Mediana Edad , Monitoreo Fisiológico/instrumentación , Pronóstico , Estudios Prospectivos , Reproducibilidad de los Resultados , Accidente Cerebrovascular/complicaciones , Accidente Cerebrovascular/mortalidad , Análisis de Supervivencia , Termodilución/instrumentación , Resultado del TratamientoRESUMEN
The routine application of an arterial thermal-dye-dilution technique (so called COLD-Monitoring) offers new perspectives in the hemodynamic management of critically ill patients using a small invasive technique. COLD-Monitoring employs a computerized analysis of a double-indicator (temperature and dye) dilution technique which requires only a central venous catheter and a special fibre optic catheter with a temperature probe applied to the femoral artery. Especially in critically ill patients with septic course or multiple organ failure (MOF) COLD-monitoring serves to exactly measure volume and therefore distribution, to objectify capillary leakage by extravascular lung water index, to check the excretoric liver-function by plasma-deviation-rate of ICG and to perform a well controlled epinephrine therapy by measuring cardiac function index and systemic vascular resistance index.
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Cateterismo Cardíaco/instrumentación , Cuidados Críticos , Técnica de Dilución de Colorante/instrumentación , Monitoreo Fisiológico/instrumentación , Insuficiencia Multiorgánica/terapia , Complicaciones Posoperatorias/terapia , Procesamiento de Señales Asistido por Computador/instrumentación , Síndrome de Respuesta Inflamatoria Sistémica/terapia , Hemodinámica/fisiología , Humanos , Pruebas de Función Hepática/instrumentación , Insuficiencia Multiorgánica/fisiopatología , Complicaciones Posoperatorias/fisiopatología , Sensibilidad y Especificidad , Síndrome de Respuesta Inflamatoria Sistémica/fisiopatologíaAsunto(s)
Técnica de Dilución de Colorante/estadística & datos numéricos , Defectos de los Tabiques Cardíacos/diagnóstico , Verde de Indocianina , Esterilización/métodos , Adulto , Cateterismo Cardíaco/economía , Cateterismo Cardíaco/instrumentación , Técnica de Dilución de Colorante/economía , Técnica de Dilución de Colorante/instrumentación , HumanosRESUMEN
Continuous measurement of arterial blood density after bolus injection of fluids of different density into the right atrium has been used to measure cardiac output and mean transit time through the central circulation. The transit time distribution for density, however, differs from that for plasma-phase tracers such as indocyanine green. This difference may yield important information about red cell transit times through the microcirculation. We analyzed the potential of the density technique to resolve small changes in transit time distributions. Rayleigh's Method was used to calculate the relationship between density distribution within the U-tube and frequency of oscillation. Fourier integral transformation of a functional representation of indocyanine green dye curves provided an estimate of amplitude versus frequency for likely input density signals. We found that the ability of the densitometer to accurately follow blood density changes depends upon physiologic parameters associated with the experimental animal and upon the physical characteristics of the densitometer itself. Even for small animals, such as a rabbit, the densitometer theoretically has the ability to accurately follow rapid density changes over time.
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Tiempo de Circulación Sanguínea , Fenómenos Fisiológicos Sanguíneos , Gasto Cardíaco , Densitometría/métodos , Animales , Densitometría/instrumentación , Perros , Técnica de Dilución de Colorante/instrumentación , Eritrocitos/fisiología , Estudios de Evaluación como Asunto , Atrios Cardíacos , Verde de Indocianina/administración & dosificación , Inyecciones , Microcirculación , Monitoreo Fisiológico/instrumentación , Monitoreo Fisiológico/métodos , Oscilometría , Plasma , Conejos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Cloruro de Sodio/administración & dosificación , Factores de TiempoRESUMEN
A method is described for the measurement of cardiac output and oxygen saturation in closed-chest rats using a small (2.4 F) commercially available fiberoptic catheter and a reflection-spectral-photometer. Positioned in the aortic arch, the catheter functions as an oxymeter for oxygen saturation and as a densitometer for measurement of indocyanine green, obviating the need for blood removal and passage through a densitometer. The sensitivity and reproducibility of this method were characterized in 90 rats by thermodilution, radiolabeled microspheres, and electromagnetic flow methods as standard references. Basal cardiac output as well as changes in cardiac output during isoproterenol infusion and blood removal and replacement were measured. In addition, multiple measurements of cardiac output over 1 min were used to document the method's suitability in constructing a ventricular function curve. With the fiberoptic catheter, cardiac output varied predictably with anesthesia, with rats on dial-urethane (n = 23) having values of 150 +/- 39 (SD) ml/min/kg and 2 and 1% enflurane (18-35 rats per group) yielding cardiac outputs of 190 +/- 60 and 236 +/- 77 ml/min/kg, respectively. Pentobarbital produced the least cardiovascular depression (n = 15) with an average cardiac output of 322 +/- 22 ml/min/kg. The average cardiac output with this method in 90 rats (regardless of anesthesia) was 214 +/- 91 (SD). This value was comparable to cardiac output values determined in paired experiments from radiolabeled microspheres (9 rats) 220 +/- 43, electromagnetic flow (11 rats) 177 +/- 33, and a subset of rats with thermodilution (231 +/- 45 ml/min/kg). The within measurement (repeat measurements) variability with the fiberoptic method was consistently less than the rat-to-rat variability when compared to the thermal and radiolabeled microsphere methods, but it was comparable to electromagnetic flow. The method can be used when rapid measurements (4 measurements within 60 s) of cardiac output are required, as in constructing a ventricular function curve, and can readily detect small changes in cardiac output during controlled hemorrhage and isoproterenol infusion. In summary, this method gives measurement of oxygen saturation and cardiac output by dye dilution without blood removal. There is less surgical preparation than required for electromagnetic cardiac output, and it is an alternative to the thermodilution method.
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Cateterismo Cardíaco/instrumentación , Gasto Cardíaco , Técnica de Dilución de Colorante/instrumentación , Animales , Tecnología de Fibra Óptica , Masculino , Microesferas , Consumo de Oxígeno , Ratas , Ratas EndogámicasRESUMEN
An Automatic Dye Dilution Processor (ADP) based on a microprocessor is applied to a hydraulic model to process on-line dilution curves, using saline or thermodilution methods. A low cost, F8 microcomputer with minimum parts configuration was used in an Automatic Dilution Processor (ADP) system. Software allows an operator to select methods, amount of indicator to be injected, cell calibration constant, and temperature step. Care has been taken in the curve data processing, to avoid errors when recirculation occurs. The system is used, together with an open hydraulic model, for flow measurement demonstration, and the estimation of cell calibration constant.
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Computadores , Técnica de Dilución de Colorante/instrumentación , Microcomputadores , Modelos Estructurales , Calibración , Diseño de Equipo , Matemática , Termodilución/instrumentaciónRESUMEN
Pulmonary extravascular water volume was obtained as the lung thermal volume (LTV) in mongrel dogs (n = 31) by double indicator dilution method, using negative heat and indocyanine green. We used a technic of one injection site (right atrium) and two sampling sites, i.e., pulmonary artery trunk and aortic root. In 13 dogs, cardiac outputs determined simultaneously from thermodilution curves in pulmonary artery trunk, aortic root and from dye dilution curve in aortic root, were in a good agreement with a coefficient of variation of +/- 12%. Lung thermal volume measured twice within a period of 5 minutes in 17 dogs, gave closely similar values with a coefficient of variation of +/- 9%. Lung thermal volume was 5.7 +/- 1.1 ml/kg (mean +/- SD) and corresponding "weighed lung water" (WLW), which was measured by destructive, direct method, was 5.0 +/- 1.0 ml/kg, the ratio of LTV to WLW (LTV/WLW) being 1.2 +/- 0.2 in control state. LTV/WLW ratio was 1.2 +/- 0.2 in 11 dogs loaded with dextran, and 1.1 +/- 0.1 in 6 dogs loaded with alloxan. Thus the lung thermal volume slightly exceeded WLW. In order to evaluate the extent to which the thermal diffusion into the left ventricular wall would cause LTV to slightly overestimate the pulmonary extravascular water volume, dye dilution curves and thermodilution curves were recorded simultaneously in the left atrium (LA) and aortic root (Ao) in a total of 25 runs in 5 dogs. The ratio of LTV obtained in LA to that in Ao was 0.9 +/- 0.1 (mean +/- SD). It was concluded that the pulmonary extravascular water volume was overestimated, by about 10% due to the thermal diffusion into the left ventricular wall.
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Agua Corporal/análisis , Técnica de Dilución de Colorante , Técnicas de Dilución del Indicador , Pulmón/análisis , Termodilución/métodos , Aloxano , Animales , Aorta/fisiología , Gasto Cardíaco , Dextranos , Perros , Técnica de Dilución de Colorante/instrumentación , Mediciones del Volumen Pulmonar , Arteria Pulmonar/fisiología , Termodilución/instrumentación , Función VentricularRESUMEN
In vitro and in vivo indicator-dilution measurements are made with a fluorescent indicator and a novel detection system using a catheter containing a single optical fiber that carries both the exciting and returning fluorescent light. These fluorescent-dilution measurements are compared with simultaneous green dye-dilution measurements. The double-indicator-dilution measurement of extravascular lung water using heat and fluorescence is compared with gravimetric measurements. Also investigated is the sensitivity of the fluorescent measurement to changes in O2 saturation and hematocrit of the blood. An example of the measurement of a right-to-left heart shunt with this new indicator is given.
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Técnica de Dilución de Colorante/instrumentación , Colorantes Fluorescentes , Animales , Perros , Espacio Extracelular/análisis , Femenino , Hematócrito , Pulmón/análisis , Masculino , Métodos , Oxígeno/sangre , PorcinosRESUMEN
The video dilution technique for measuring blood flow consists of electronically and mathematically processing video-taped selective arteriograms to measure the flow in selectively catheterized arteries and to express this flow as a fraction of the flow in any reference artery. Flows were measured by video dilution and an electromagnetic flowmeter in ten dogs; the correlations were excellent. Video dilution flows were also measured in 105 patients. The technique is accurate, simple, and adds no risk to routine selective arteriography.
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Angiografía , Técnicas de Dilución del Indicador/instrumentación , Enfermedades Vasculares/diagnóstico , Grabación de Cinta de Video , Adolescente , Adulto , Anciano , Animales , Arteriopatías Oclusivas/diagnóstico , Arteriosclerosis/diagnóstico , Fístula Arteriovenosa/diagnóstico , Cateterismo , Perros , Técnica de Dilución de Colorante/instrumentación , Femenino , Displasia Fibromuscular/diagnóstico , Humanos , Masculino , Matemática , Enfermedades Vasculares/diagnóstico por imagenRESUMEN
The dilution technique for determining cardiac output using indocyanine green dye is limited in patients weighing less than 20 kg because of the obligatory volume loss. Reproducible achieved using the green dye dilution method by the establishment of a low flow peripheral arteriovenous shunt. The shunt materials were treated with thromboresistant agents--TDMAC (7%) and albumin (1 g/dl)--to facilitate the use of this technique without heparin. For A-V shunt flow rates of 8-30 cc/min reproducible values of cardiac output were obtained for up to 38 hours which were in good agreement with determinations made using the conventional technique of dye dilution.
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Derivación Arteriovenosa Quirúrgica/instrumentación , Gasto Cardíaco , Técnica de Dilución de Colorante/instrumentación , Animales , Niño , Perros , Humanos , Polietilenos , Politetrafluoroetileno , Elastómeros de Silicona , Trombosis/prevención & controlRESUMEN
This study assesses a precalibrated dichromatic earpiece densitometer and microprocessor for the measurement of cardiac output by indocyanine green dye dilution. The measured cardiac output is compared with values of cardiac output simultaneously determined using a cuvette densitometer. The microprocessor computation of cardiac output agreed very closely with the cardiac output determined by manual calculation from the same dye dilution curves (standard deviation +/- 1.47%). The reproducibility of the earpiece densitometer (standard deviation +/- 5.2%) was virtually identical to that of the cuvette densitometer (+/- 5.3%). In a comparison of earpiece and cuvette densitometers for 60 measurements of cardiac output following pulmonary arterial injection of dye and for 50 measurements following femoral venous injection of dye, correlation coefficients were 0.83 and 0.78 and the standard deviations of the differences of simultaneous measurements were 7.2% and 8.3% respectively. The instrument offers an accurate reproducible and relatively noninvasive technique for measuring cardiac output.