RESUMO
Hemodynamic care during postoperative management of myocardial revascularization should include vasorelaxing drugs to insure adequate graft and coronary flow, and stimulation of stroke volume to maintain vascular perfusion pressure. We tested the cardiac (inotropic and lusitropic) and vascular (relaxant) effects of diltiazem (0.1 nM to 0.1 mM), dobutamine (10 microM to 10 mM) and amrinone (10 microM to 1 mM) on isolated rat atria and thoracic aorta, and also on isolated human saphenous vein (HSV) and human mammary artery (HMA). Dobutamine produced a maximal positive inotropic effect (+dF/dt max = 29 +/- 7%) at its ED50 for aortic relaxation (88 +/- 7 microM). Conversely, at their ED50 for aortic relaxation diltiazem depressed myocardial contractility and amrinone did not exhibit myocardial effects. In HSV and HMA contracted with 80 mM potassium, diltiazem and dobutamine (but not amrinone) had a vasorelaxant activity similar to that in rat aorta. Norepinephrine-contracted human vessels were significantly more sensitive than potassium-contracted vessels to the relaxant effect of amrinone (ED50 HMA = 15 +/- 5 microM, ED50 HSV = 72 +/- 31 microM, P < 0.05). We conclude that at concentrations still devoid of myocardial effects dobutamine and amrinone are effective dilators in graft segment vessels and rat aorta contracted by membrane depolarization. If the difference between aortic and myocardial tissue still holds in human tissues, at the appropriate concentrations these drugs should be expected to improve cardiac performance while still contributing to the maintenance of graft patency.
Assuntos
Amrinona/farmacologia , Cardiotônicos/farmacologia , Diltiazem/farmacologia , Dobutamina/farmacologia , Revascularização Miocárdica , Vasodilatadores/farmacologia , Animais , Aorta/efeitos dos fármacos , Aorta/fisiologia , Feminino , Átrios do Coração/efeitos dos fármacos , Humanos , Masculino , Artéria Torácica Interna/efeitos dos fármacos , Artéria Torácica Interna/fisiologia , Ratos , Ratos Sprague-Dawley , Veia Safena/efeitos dos fármacos , Veia Safena/fisiologiaRESUMO
BACKGROUND: Vasoactive drugs used in the reanimation of septic patients, can modify splanchnic perfusion. AIM: To compare the effects of dobutamine and amrinone on gastric intramucosal pH (pHi), lactate levels and hemodynamics in surgical patients with compensated septic shock. PATIENTS AND METHODS: Fourteen postoperative patients with abdominal sepsis and compensated septic shock (pHi < 7.32 or lactate > 2.5 mmol/l) were studied in a prospective, randomized, unblinded study. Patients were randomized to receive (Group 1, n = 7) dobutamine at 5 micrograms/Kg/min or (Group 2, n = 7) amrinone at 5 micrograms/Kg/min. Hemodynamic data, arterial lactate and pHi were measured before and 30, 60 and 120 minutes after starting drug infusion. RESULTS: Both drugs were associated with a decrease in lactate levels. Dobutamine infusion, but not amrinone, increased gastric pHi, as well as cardiac index and oxygen delivery. CONCLUSIONS: An improvement in gastric pHi associated with an increase in oxygen delivery, was observed with dobutamine. Amrinone showed no effect at the fixed, low dose used in the study.
Assuntos
Amrinona/farmacologia , Cardiotônicos/farmacologia , Dobutamina/farmacologia , Hemodinâmica/efeitos dos fármacos , Choque Séptico/tratamento farmacológico , Circulação Esplâncnica/efeitos dos fármacos , Vasodilatadores/farmacologia , Acidose Láctica/sangue , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos ProspectivosRESUMO
Background: Vasoactive drugs used in the reanimation of septic patients, can modify splanchnic perfusion. Aim: To compare the effects of dobutamine and amrinone on gastric intramucosal pH (pHi), lactate levels and hemodynamics in surgical patients with compensated septic shock. Patients and methods: Fourteen postoperative patients with abdominal sepsis and compensated septic shock (pHi <7.32 or lactate >2.5 mmol/l) were studied in a prospective, randomized, unblinded study. Patients were randomized to receive (Group 1, n=7) dobutamine at 5 µg/Kg/min or (Group 2, n=7) amrinone at 5 µg/Kg/min. Hemodynamic data, arterial lactate and pHi were measured before and 30, 60 and 120 minutes after starting drug infusion. Results: Both drugs were associated with a decrease in lactate levels. Dobutamine infusion, but not amrinone, increased gastric pHi, as well as cardiac index and oxygen delivery. Conclusions: An improvement in gastric pHi associated with an increase in oxygen delivery, was observed with dobutamine. Amrinone showed no effect at the fixed, low dose used in the study
Assuntos
Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Amrinona/farmacologia , Dobutamina/farmacologia , Choque Séptico/tratamento farmacológico , Complicações Pós-Operatórias/tratamento farmacológico , Abdome Agudo/cirurgia , Lactatos/metabolismo , Lactatos/sangue , Circulação Esplâncnica , Concentração de Íons de Hidrogênio , Choque Séptico/etiologiaRESUMO
La amrinona y milrinona forman parte de un grupo de drogas que poseen propiedades inótropas y vasodilatadoras. Su mecanismo de acción es diferente a la dopamina. El resultado de su acción es un aumento de la contractilidad miocárdica asociado a una disminución de la resistencia vascular periférica. El objetivo de este trabajo es entregar una revisión de la literatura reciente en cuanto al uso de estos agentes en pediatría
Assuntos
Humanos , Amrinona/farmacologia , Cardiotônicos/farmacologia , Amrinona , Amrinona , Contração Miocárdica , Dobutamina/farmacologia , Quimioterapia Combinada , Resistência Vascular/efeitos dos fármacosRESUMO
OBJECTIVES: This study sought to determine whether the response to amrinone in patients with severe baseline left ventricular dysfunction can predict improvement in left ventricular ejection fraction after coronary artery bypass graft surgery. BACKGROUND: Previous studies have suggested that the inotropic response to dobutamine can identify viable myocardium in the setting of chronic coronary disease and left ventricular dysfunction. However, increased oxygen demand stimulated by dobutamine can lead to superimposition of ischemia on the hibernating state, potentially confounding interpretation of results. Amrinone is an inotropic agent that does not critically augment myocardial oxygen demand and may be useful for identification of hibernating myocardium in the chronically ischemic state. METHODS: Forty-four consecutive patients with coronary artery disease and left ventricular ejection fraction < 40% referred for coronary artery bypass graft surgery underwent amrinone stimulation (1 mg/kg body weight). Left ventricular ejection fraction was determined before amrinone stimulation, 20 min after infusion and 21 days after bypass surgery. RESULTS: Baseline ejection fraction was 28 +/- 7% (mean +/- SD). Ejection fraction increased to 35 +/- 5% after amrinone stimulation (p < 0.0001) and to 33 +/- 6% after bypass surgery (p < 0.0001). Postbypass ejection fraction was significantly correlated with postamrinone ejection fraction (r = 0.65, p < 0.0001). Furthermore, the change in ejection fraction from baseline to after bypass surgery was highly correlated with the change in ejection fraction after amrinone stimulation (r = 0.75, p < 0.0001). Of 13 patients with an increase in ejection fraction > or = 10% after amrinone, all 13 had an increase of at least 8% and 11 (85%) of 13 had an increase > or = 10% after bypass surgery. In contrast, of 31 patients with an increase in ejection fraction < 10% after amrinone, only 2 (6%) had an increase > or = 10% (p < 0.0001) and 28 (90%) of 31 had an increase < 5% after bypass surgery. CONCLUSIONS: Augmentation of myocardial contraction by amrinone in patients with chronic coronary artery disease and severe baseline left ventricular dysfunction predicts improvement in left ventricular ejection fraction after coronary artery bypass graft surgery.
Assuntos
Amrinona , Cardiotônicos , Ponte de Artéria Coronária , Doença das Coronárias/fisiopatologia , Doença das Coronárias/cirurgia , Volume Sistólico , Idoso , Idoso de 80 Anos ou mais , Amrinona/farmacologia , Cardiotônicos/farmacologia , Feminino , Hemodinâmica/efeitos dos fármacos , Humanos , Masculino , Pessoa de Meia-IdadeAssuntos
Humanos , Masculino , Pessoa de Meia-Idade , Perfusão , Doença das Coronárias , Contração Miocárdica , Função Ventricular Esquerda , Revascularização Miocárdica/métodos , Amrinona/farmacologia , Tomografia Computadorizada de Emissão de Fóton Único , Dipiridamol/farmacologia , Estimulação Química , RadioisótoposRESUMO
En el presente estudio hemos comparado los efectos de Milrinona (M), un nuevo fármaco inótropo, positivo con un inhibidor de enzima convertidora, Captopril (C), en la condición clínica y respuesta adrenérgica al esfuerzo físico leve en pacientes con insuficiencia cardíaca congestiva (ICC) en CF III. El estudio randomizado, cruzado y doble ciego evaluó los efectos de M, 10 mg c/6 hr. o C 50 mg c/8 hr. durante 9 semanas, comparados con placebo, en 16 pacientes con ICC (6 de causa isquéemica, 10 por miocardiopatíia dilatada), que recibían digital y diuréticos. Se determinó un score clínico (SC), que incluía síntomas, examen físico y Rx. tórax, (rango 0-14), la fracción de eyección radio isotópica (FE) y la actividad de renina plasmática (ARP). La noradrenalina plasmática (NAD) se midió en reposo (r) y a iguales niveles de esfuerzo físico leve (e) (6 min. Naughton, VO2 8-9 ml/kg/min.). El score clínico mejoró en forma significativa y similar por efectos de ambas drogas (5.2+-0.4 a 4.4+-0.5, 4.1+-0.4 respectivamente, p<0.01). Lo mismo ocurrió con la fracción de eyección de VI que aumentó de 23.6+-2.6% por efecto de milrinona y a 28.6+-3.2% por efecto de captopril, (p<0.01). La respuesta neurohumoral fue diferente ya que no hubo modificaciones de la ARP o NAD en reposo y esfuerzo por efecto de Milrinona. La ARP aumentó (1.6+-0.5 a 5.3+-1.5 ng/ml/hr y la NAD en esfuerzo disminuyó (1228+-158 a 820+-100 pg/ml) por efecto de Captopril (p<0.01). La elevación de ARP y la menor respuesta adrenégica al esfuerzo físico observada con C confirma un diferente efecto humoral con respecto de M e indican que favorece una mejor adaptación al esfuerzo físico en pts. con ICC