Effect of Feeding and Suction on Gastric Impedance Spectroscopy Measurements.

A specific device and system has been developed and tested for clinical monitoring of gastric mucosal reactance in the critically ill as an early warning of splanchnic hypoperfusion associated with shock and sepsis. This device has been proven effective in clinical trials and is expected to become commercially available next year. The system uses a combination nasogastric tube and impedance spectroscopy probe as a single catheter. Because this device has a double function, the question is: Does enteral feeding or suction affect the gastric reactance measurements? This study was designed to evaluate the effect of feeding and suction on the measurement of gastric impedance spectroscopy in healthy volunteers. Impedance spectra were obtained from the gastric wall epithelia of 18 subjects. The spectra were measured for each of the following conditions: postinsertion of gastric probe, during active suction, postactive suction, and during enteral feeding (236 ml of nutritional supplement). Impedance spectra were reproducible in all volunteers under all conditions tested. There was a slight increase in impedance parameters after suction, and a decrease in impedance after feeding; however, these observed differences were insignificant compared to patient-to-patient variability, and truly negligible compared with previously observed changes associated with splanchnic ischemia in critically ill patients. Our results demonstrate that suction or feeding when using the impedance spectro-metry probe/nasogastric tube does not significantly interfere with gastric impedance spectrometer measurements.

Clinical practice guidelines for diagnostic and treatment of the chronic heart failure.

Chronic heart failure continues to be one of the main causes of impairment in the functioning and quality of life of people who suffer from it, as well as one of the main causes of mortality in our country and around the world. Mexico has a high prevalence of risk factors for developing heart failure, such as high blood pressure, diabetes, and obesity, which makes it essential to have an evidence-based document that provides recommendations to health professionals involved in the diagnosis and treatment of these patients. This document establishes the clinical practice guide (CPG) prepared at the initiative of the Mexican Society of Cardiology (SMC) in collaboration with the Iberic American Agency for the Development and Evaluation of Health Technologies, with the purpose of establishing recommendations based on the best available evidence and agreed upon by an interdisciplinary group of experts. This document complies with international quality standards, such as those described by the US Institute of Medicine (IOM), the National Institute of Clinical Excellence (NICE), the Intercollegiate Network for Scottish Guideline Development (SIGN) and the Guidelines International Network (G-I-N). The Guideline Development Group was integrated in a multi-collaborative and interdisciplinary manner with the support of methodologists with experience in systematic literature reviews and the development of CPG. A modified Delphi panel methodology was developed and conducted to achieve an adequate level of consensus in each of the recommendations contained in this CPG. We hope that this document contributes to better clinical decision making and becomes a reference point for clinicians who manage patients with chronic heart failure in all their clinical stages and in this way, we improve the quality of clinical care, improve their quality of life and reducing its complications.

La insuficiencia cardiaca crónica sigue siendo unas de las principales causas de afectación en el funcionamiento y en la calidad de vida de las personas que la presentan, así como una de las primeras causas de mortalidad en nuestro país y en todo el mundo. México tiene una alta prevalencia de factores de riesgo para desarrollar insuficiencia cardiaca, tales como hipertensión arterial, diabetes y obesidad, lo que hace imprescindible contar con un documento basado en la evidencia que brinde recomendaciones a los profesionales de la salud involucrados en el diagnóstico y el tratamiento de estos pacientes. Este documento establece la guía de práctica clínica (GPC) elaborada por iniciativa de la Sociedad Mexicana de Cardiología (SMC) en colaboración con la Agencia Iberoamericana de Desarrollo y Evaluación de Tecnologías en Salud, con la finalidad de establecer recomendaciones basadas en la mejor evidencia disponible y consensuadas por un grupo interdisciplinario y multicolaborativo de expertos. Cumple con estándares internacionales de calidad, como los descritos por el Institute of Medicine de los Estados Unidos de América (IOM), el National Institute of Clinical Excellence (NICE) del Reino Unido, la Intercollegiate Network for Scottish Guideline Development (SIGN) de Escocia y la Guidelines International Network (G-I-N). El grupo de desarrollo de la guía se integró de manera interdisciplinaria con el apoyo de metodólogos con experiencia en revisiones sistemáticas de la literatura y en el desarrollo de GPC. Se llevó a cabo y se condujo metodología de panel Delphi modificado para lograr un nivel de consenso adecuado en cada una de las recomendaciones contenidas en esta GPC. Esperamos que este documento contribuya para la mejor toma de decisiones clínicas y se convierta en un punto de referencia para los clínicos que manejan pacientes con insuficiencia cardiaca crónica en todas sus etapas clínicas, y de esta manera logremos mejorar la calidad en la atención clínica, aumentar la calidad de vida de los pacientes y disminuir las complicaciones de la enfermedad.

Incidence of gastric mucosal injury as measured by reactance in critically ill patients.

Gastric reactance has been proposed as a measure of mucosal ischemic injury in the critically ill. The purpose of this study was to evaluate the incidence of gastric mucosal injury as measured by gastric reactance in different subgroups of critical patients. We studied 100 adult patients admitted to 7 different hospital intensive care units, requiring a nasogastric tube. Gastric impedance measurements were continuously obtained from each patient for 24 hours. Patients were managed based on conventional protocols by hospital staff, blinded to the changes in gastric impedance parameters. The low-frequency central reactance (X L) reflects tissue edema caused by prolonged ischemia. The previously reported threshold of X L ≥ 13 - jΩ was used to classify injured mucosa; 80% of all patients had mean X L above this threshold. No significant differences were found in the incidence of mucosal ischemia between medical versus surgical, hemodynamic versus respiratory or neurological patients. Significant lower urine output was found in patients with X L above threshold (P < .01); also, there was a significant effect of fluid balance in those patients (P < .05). More complicated patients had higher average reactance. This study shows that gastric ischemia as estimated by gastric reactance has a very high incidence in the critically ill, independently of the reason for admission. High reactance is related with higher morbidity in agreement with other reports using different methods of assessing splanchnic hypoperfusion in this patient population.

Mechanical factors of cardiovascular risk in systemic arterial hypertension. A new sign of arterial rigidity.

UNLABELLED: ANTECEDENT: By means of sphygmokinetocardiography (SKCG) we developed and arterial rigidity index (ARI) which measure the pulse wave aortic carotid reflexion time over the left ventricular ejection time (LVET). This index, together with the pulse wave velocity (PWV) and the pulse pressure (PP) are indicators of arterial stiffness. In this paper we measured these index in 27 systemic artery hypertension. Cases (group A, GA), with and without left ventricular hypertrophy (subgroups: A1 SGA1, n = 13, and A2, SGA2, n = 14), respectively, and 28 normotensive cases (group B, GB). PROTOCOL: In two occasions: after 3 minutes of sitting position (SP) and after 3 minute of logging in an upright position (UP), blood pressure, ARI, PP, PWV (aortic-hand finger distance/aorto-hand finger pulse time) and R-IV interval (electrocardiographic R wave-left early ventricular kinetocardiography deflexion) were measured. RESULTS: Demography was similar in GA and GB. Systolic, diastolic and pulse pressure were significantly higher in GA vs GB. LVET (ms) was lower in GA vs GB in SP (268 +/- 42 vs 274 +/- 40, p < 0.001, respectively) and higher postexercise UP (280 +/- 42 vs 244 +/- 46, p < 0.001). PWV m/s were higher in SP in GA vs GB (9.8 +/- 2.8 vs 7.4 +/- 1.2, p < 0.001, respectively) and in UP (10.1 +/- 1.9 vs 7.9 +/- 9, p < 0.001, respectively). ARI was lower in UP in GA vs GB (0.48 +/- 0.3 vs 0.80 +/- 0.3, p < 0.003). Correlation index of PP vs SBP, vs DBP and vs PWV were significant in SP and in UP. Height had a significant correlation vs ARI in SP and UP (r = 0.60, p < 0.01, and r = 0.42, p < 0.05, respectively). CONCLUSION: PWV is increased in GA vs GB patients. The ARI index is lower in GA vs GB cases in post exercise. PWV and PP showed a statistical significant correlation; height vs ARI had also a significant correlation: SKCG is a new method, that uses a not commercially instrument, which should have clinical application.

Mechanical factors of cardiovascular risk in systemic arterial hypertension: A new sign of arterial rigidity / Factores mecánicos de riesgo cardiovascular en la hipertensión arterial sistémica: Un nuevo signo de rigidez arterial

Antecedent: By means of sphygmokinetocardiography (SKCG) we developed and arterial rigidity index (ARI) which measure the pulse wave aortic carotid reflexion time over the left ventricular ejection time (LVET). This index, together with the pulse wave velocity (PWV) and the pulse pressure (PP) are indicators of arterial stiffness. In this paper we measured these index in 27 systemic artery hypertension. Cases (group A, GA), with and without left ventricular hypertrophy (subgroups: A1 SGA1, n = 13, and A2, SGA2, n = 14), respectively, and 28 normotensive cases (group B, GB). Protocol: In two occasions: after 3 minutes of sitting position (SP) and after 3 minute of jogging in an upright position (UP), blood pressure, ARI, PP, PWV (aortic-hand finger distance/aorto-hand finger pulse time) and R-IV interval (electrocardiographic R wave-left early ventricular kinetocardiography deflexion) were measured. Results: Demography was similar in GA and GB. Systolic, diastolic and pulse pressure were significantly higher in GA vs GB. LVET (ms) was lower in GA vs GB in SP (268 ± 42 vs 274 ± 40, p < 0.001, respectively) and higher postexercise UP (280 ± 42 vs 244 ± 46, p < 0.001). PWV m/s were higher in SP in GA vs GB (9.8 ± 2.8 vs 7.4 ± 1.2, p < 0.001, respectively) and in UP (10.1 ± 1.9 vs 7.9 ± 9, p < 0.001, respectively). ARI was lower in UP in GA vs GB (0.48 ± 0.3 vs 0.80 ± 0.3, p < 0.003). Correlation index of PP vs SBP, vs DBP and vs PWV were significant in SP and in UP. Height had a significant correlation vs ARI in SP and UP (r = 0.60, p < 0.01, and r = 0.42, p < 0.05, respectively). Conclusion: PWV is increased in GA vs GB patients. The ARI index is lower in GA vs GB cases in post exercise. PWV and PP showed a statistical significant correlation; height vs ARI had also a significant correlation: SKCG is a new method, that uses a not commercially instrument, which should have clinical application.

Antecedentes: Mediante esfigmoquinetocardiografía (EQCG) se desarrolló un índice de rigidez arterial (IRA) que mide el tiempo aorto-onda de reflexión arterial sobre el período expulsivo. Este índice junto con la velocidad de la onda del pulso (VOP) y la presión del pulso (PP) son signos de rigidez arterial. Aquí medimos estos indicadores en 27 casos con hipertensión arterial (grupo A, GA) con y sin hipertrofia del ventrículo izquierdo: subgrupo A1, SGA1 de 13 casos y 14 individuos (subgrupo A2, SGA2) respectivamente y 28 casos normotensos (grupo B, GB). Protocolo: En 2 ocasiones: después de 3 minutos de posición sedente (PS) y después de 3 minutos de trote en posición ortostática (PO), se midió: la presión arterial (PA), el IRA, la VOP (distancia aorta-dedo-mano/tiempo de la onda del pulso aorta-dedo-mano) la PP y el intervalo R-IV (onda R del electrocardiograma -final de la deflexión ventricular temprana en el EQCG. Resultados: La demografía fue similar en ambos grupos. La PP, las presiones sistólica y diastólica fueron más altas en el GA vs el GB. El PE (ms) fue menor en el GA vs el GB en PS (268 ± 42 vs 274 ± 40, p < 0.001, respect.) y más alto en PO (280 ± 42 vs 244 ± 46, p < 0.001) en el GA vs GB. La VOP m/s, fue más alta en PS en GA vs GB (9.8 ± 2.8 vs 7.4 ± 1.2, p < 0.001, respect.) y en PO (10.1 ± 1.9 vs 7.9 ± 9, p < 0.001, respect.). El IRA fue menor en PO en el GA vs GB (0.48 ± 0.3 vs 0.8 ± 0.3, p < 0.003). El índice de correlación de la PP vs PAS, PA y VOP tuvo significancia estadística en PS y en PO. La talla correlacionó con el IRA (r = 0.6, p < 0.01 en PS y r = 0.42, p < 0.05 en PO). Conclusiones: La VOP está aumentada y el IRA más bajo en el GA vs GB en PO (lo que indica mayor rigidez arterial). La VOP y la PP tuvieron correlación significativa con la talla al igual que esta última con el IRA. La EQCG es un método con aplicación clínica. (Arch Cardiol Mex 2003; 73:261-270).

Uso del levosimendan previo a la cirugía cardíaca, en pacientes con mala función ventricular / Usefulness of levosimendan in patients with ventricular dysfunction before surgery

El propósito de este trabajo fue observar los resultados hemodinámicos inmediatos (primeras 24 hs) en pacientes con mala función ventricular (< 40%), considerados de alto riesgo quirúrgico, en los cuales 24 a 48 hs antes de la cirugía recibían una infusión por 24 hs con levosimendan. Se incluyeron 4 pacientes de sexo masculino con edad promedio de 55.50 (+ 7.93 años) con una fracción de eyección del ventrículo izquierdo de 31 (+ 5.47%), 2 de ellos sometidos a cambio valvular, otro a revascularización miocárdica y el cuarto se sometió a procedimiento combinado (revascularización + cambio valvular). El comportamiento de los parámetros hemodinámicos estuvo estable, sin necesidad de altas dosis de los inotrópicos y vasopresores clásicos en el postoperatorio. Conclusión: El levosimendan podría ser un inotrópico de gran aplicación en este grupo de pacientes debido a su novedoso mecanismo de acción y a sus sostenidos efectos hemodinámicos luego de terminada su infusión.

The purpose of this work was to observe the hemodynamic stability on the first 24 hours in 4 patients with ventricular dysfunction (Ejected Fraction < 40 %), considered of high surgical risk, in which 24 at 48 hr before the surgery received an infusion of Levosimendan for 24 hours. This 4 patients was male, with age 55.5 ± 7.9 years old, a left ventricle ejection of fraction (LVEF) of 31 ± 5.47%; Two of them was underwent to valve replacement, another one to coronary artery bypass graft and the last one patient underwent combined procedure (coronary artery bypass graft surgery and valve replacement). The behavior of the hemodynamic parameters was stable, without necessity of uses high dose of the inotropics and classic vasopresores in the postoperative. Conclusion: the Levosimendan could be an inotropic of great application in this group of patient due to its novel action mechanism and to its sustained hemodynamic effects after having finished its infusion.

Provocación y medición de la velocidad de la onda pulsátil retrograda en sujetos normales e hipertensos sistémicos / Velocity of reflexive arterial pulse wave in normal vs hypertensive subjects

No existen métodos incruentos de provocación de las ondas retrógradas (OsRs). Aquí se describe que durante la esfigmomanometría compresiva del antebrazo se provoca OsRs que se registran en el brazo con un equipo original que mide la velocidad de la onda anterógrada (VOA) en el segmento braquio-antebraquial y la velocidad de la onda retrógrada (VOR), provocada por la maniobra, en el territorio antebraquio-braquial. El procedimiento: 1) detecta y digitaliza señales de ECG y de oscilopulsos del brazo y del antebrazo y 2) mide la VOA y la VOR (tiempo de conducción/distancia entre detectores brazo-antebrazo y antebrazo-brazo respectivamante). Se estudiaron 30 sujetos normales y 37 con hipertensión arterial (16 con y 21 sin hipertrofia del ventrículo izquierdo), cuyas cifras de presión arterial fueron 121 ñ 11 vs 159 ñ 90 mm Hg, Grupos A y B, respectivamante. Resultados. En todos los casos, menores uno, se provocaron OsRs. La VOA (en metros/segundos) fue de 6.0 ñ 0.9 para el GA vs 7.5 ñ 1.3, p < 0.001 para el GB; la VOR 1.8 ñ 0.3 vs 2.5 ñ 0.7, p< 0.001. Los sujetos del GB con hipertrofia ventricular vs los que no la tuvieron presentaron una mayor VOR (m/s), 2.7 ñ 0.6 vs 2.3 ñ 0.6, p= 0.07. La velocidad aumentada de las OsRs que manifiestan los sujetos con hipertensión arterial vs los normales se debe probablemente al exceso de rigidez arterial que los primeros manifiestan. El metodo aquí propuesto provoca rebotes en forma sencilla, eficaz y reproducible

Sistema para la medición no invasiva de la velocidad del pulso arterial en diferentes territorios vasculares / A system for non-invasive measurement of arterial pulse velocity different vascular territories

La velocidad de la onda del pulso arterial (VOP) se ha utilizado como índice de rigidez arterial para valorar algunas patologías cardiovasculares. Aquí se describe el diseño y desarrollo de un sistema para determinar la VOP en las regiones aórto-braqui-húmero-radial (A - m), aórto-ileo-fémoro-pedial (A - p) y aórto-carotidea (A - L), el cual se ensayó en 36 sujetos normotensos (NT) y 34 hipertrofia ventricular izquierda (SHVI). El equipo consta de una computadora a la que se le añadió, bajo diseño específico, un convertidor de analógico, bajo diseño específico, un convertidor de analógico a digital y la electrónica y programación para tomar simultáneamante el electrocardiograma (ECG), dos pulsos fotopletismográficos, una lectura de presión y un pulso oscilométrico. Con estos datos se determinó el intervalo Q-pP (tiempo entre la onda Q de ECG y el pie del pulso periférico) lo que, tomando la distancia entre los sitios de registro y luego de calcular el periodo pre-expulsivo cardiaco, permite determinar la VOP (en metros/segundo) desde la raíz de la aorta al punto distal. Al comparar la VOP en HT vs NT (A - m: 9.3 ñ 2.6 vs. 7.2 ñ 0.8, A - L: 9.5 ñ 2.8 vs. 6.0 ñ 0.9 y A - p: 9.5 ñ 1.8 vs. 7.2 ñ 0.9), la diferencia resultó significativa (p < 0.001) en cada uno de los territorios explorados; lo mismo ocurrió al comparar los casos CHVI contra los SHVI (A - m: 10.5 ñ 1.6 vs. 8.0 ñ 1.9, A - L: 10.2 ñ 1.9 vs 8.0 ñ 1.9 y A - p: 10.5 ñ 2.0 vs. 8.6 ñ 1.2) (p < 0.025). Esto es consistente con la conocida relación mayor presión - mayor rigidez y con lo reportado en otros trabajos que utilizan métodos diferentes para precisar la VOP. El método puede tener aplicación en la clínica