Adilson O. Fraga

Evidence For Myocardial Defects Under Extreme Acute Normovolemic Hemodilution With Hydroxyethyl Starch And Lactated Ringer's Solution

Acute normovolemic hemodilution (ANH) has been proposed to avoid the risks of allogenic transfusion. In reference to its cellular effects, ANH reports in the literature are scarce. Using electron microscopy (EM), we evaluated the effects of ANH on cardiac function and myocardial structure. Twenty-five dogs were prospectively randomized to a control group (n = 5) or to undergo ANH with 6% hydroxyethyl starch (HES; n = 10) or lactated Ringers solution (LR; n = 10) administered, respectively, at a ratio of 1:1 or 1:3 to the volume of blood removed. Animals were gradually hemodiluted to a hematocrit of 10%, which was accomplished in 80 min. Pulmonary artery catheter and echocardiography were used to evaluate cardiac function. Myocardial samples were taken after the last time point for electron microscopy analysis. Data were obtained during five different stages of ANH, with a mean 20-min interval between each time point. Cardiac index increased significantly in both groups during ANH. A significant decrease in oxygen delivery and oxygen consumption, as well as an increase in oxygen extraction was verified in the LR group. Echocardiography demonstrated a decline in systolic function in the LR group at the end of the experiment. Electron microscopy analysis of the myocardium revealed slight lesions in cardiac cells in the HES group, and moderate-to-significant lesions in the LR group. In this animal species, ANH with HES resulted in better preservation of cardiac function, which was demonstrated by maintenance of systolic function and oxygenation parameters. Minor loss of cellular integrity with HES, in the presence of very low levels of hemoglobin, reinforces these findings.

Anesthetic induction after treated hemorrhagic shock: experimental study comparing ketamine and etomidate

JUSTIFICATIVA Y OBJETIVOS: El sangramiento que conlleva al choque hemorragico generalmente necesita un tratamiento quirurgico bajo anestesia general. A su vez, los anestesicos pueden comprometer mas las condiciones hemodinamicas. El objetivo de este estudio fue el de comparar los efectos hemodinamicos de la cetamina y del etomidato durante la induccion anestesica en perros sometidos a un modelo experimental de choque hemorragico y reanimacion. METODO: Treinta y dos perros mestizos fueron sometidos al choque hemorragico presion-controlada, reanimacion e induccion anestesica. Despues de alcanzar la presion objeto de 40 mmHg ellos fueron divididos aleatoriamente en dos grupos de acuerdo con el liquido usado en la resucitacion: NaCl a 0.9% (32 mL.kg-1) y NaCl a 7,5% (4 mL.kg-1). Despues de la infusion de volumen, esos grupos fueron divididos nuevamente de acuerdo con el anestesico utilizado: GI) NaCl a 0.9% y cetamina; GII) NaCl a 7.5% y cetamina; GIII) NaCl a 0.9% y etomidato; y GIV) NaCl a 7.5% y etomidato. Mediciones hemodinamicas fueron obtenidas en cinco momentos: (M0) inicial; (M1) despues del desarrollo del choque hemorragico; (M2) despues de la administracion de soluciones; (M3) 5 minutos despues de la induccion anestesica; (M4) 15 minutos despues de la induccion anestesica. Se hizo el analisis estadistico usando el Student t test y two-way ANOVA. Fueron considerados significativos valores de p menores que 0,05. RESULTADOS: Despues de la instalacion del choque, los dos sueros reestablecieron los estandares hemodinamicos a los valores iniciales. Independiente del anestesico o del solucion utilizada, despues de la induccion anestesica la presion arterial media permanecio inalterada en todos los grupos. La presion venosa central, frecuencia cardiaca, presion capilar pulmonar y el indice de resistencia pulmonar vascular aumentaron significativamente despues de la administracion de cetamina. El indice cardiaco, el indice de resistencia vascular sistemica y el transporte de oxigeno permanecieron estables en todos los grupos. CONCLUSIONES: El etomidato o la cetamina fueron capaces de mantener la estabilidad hemodinamica en los perros que sufrieron choque hemorragico severo y que fueron tratados con NaCl a 0,9% o NaCl a 7,5%.BACKGROUND AND OBJECTIVES Bleeding causing hemorrhagic shock usually requires surgical treatment under general anesthesia. Anesthetic drugs may further compromise hemodynamics. The objective was to compare the hemodynamic effects of ketamine and etomidate during anesthetic induction in dogs submitted to an experimental model of hemorrhagic shock and resuscitation. METHODS Thirty-two mongrel dogs were submitted to a pressure-controlled hemorrhagic shock, resuscitation and anesthetic induction model. After achieving the target pressure of 40 mmHg, they were randomly assigned in two groups according to the resuscitation fluid to be used: NaCl 0.9% (32 mL.kg-1) and NaCl 7.5% (4 mL.kg-1). After volume infusion, these groups were reassigned according to anesthetic drug used: GI) NaCl 0.9% and ketamine; GII) NaCl 7.5% and ketamine; GIII) NaCl 0.9% and etomidate; and GIV) NaCl 7.5% and etomidate. Hemodynamic measurements were obtained at five moments: (M0) baseline; (M1) after bleeding to shock; (M2) after volume expansion; (M3) 5 minutes after anesthetic induction; (M4) 15 minutes after anesthetic induction. Statistical analysis was performed using Student t test and two way ANOVA. Value of p lower than 0.05, was considered significant. RESULTS After shock, both solutions restored hemodynamics to baseline values. Independently of anesthetic agent or expansion solution used, mean arterial pressure remained unaltered for all groups after induction. Central venous pressure, heart rate, pulmonary capillary wedge pressure and pulmonary vascular resistance index increased significantly after ketamine infusion. Cardiac index, systemic vascular resistance index and oxygen transport variables remained stable in all groups. CONCLUSIONS Etomidate or ketamine were able to maintain hemodynamic stability in dogs undergoing severe hemorrhagic shock treated with NaCl 0.9% or NaCl 7.5%.

Indução anestésica após o tratamento do choque hemorrágico: estudo experimental comparando a cetamina e o etomidato

JUSTIFICATIVA Y OBJETIVOS: El sangramiento que conlleva al choque hemorragico generalmente necesita un tratamiento quirurgico bajo anestesia general. A su vez, los anestesicos pueden comprometer mas las condiciones hemodinamicas. El objetivo de este estudio fue el de comparar los efectos hemodinamicos de la cetamina y del etomidato durante la induccion anestesica en perros sometidos a un modelo experimental de choque hemorragico y reanimacion. METODO: Treinta y dos perros mestizos fueron sometidos al choque hemorragico presion-controlada, reanimacion e induccion anestesica. Despues de alcanzar la presion objeto de 40 mmHg ellos fueron divididos aleatoriamente en dos grupos de acuerdo con el liquido usado en la resucitacion: NaCl a 0.9% (32 mL.kg-1) y NaCl a 7,5% (4 mL.kg-1). Despues de la infusion de volumen, esos grupos fueron divididos nuevamente de acuerdo con el anestesico utilizado: GI) NaCl a 0.9% y cetamina; GII) NaCl a 7.5% y cetamina; GIII) NaCl a 0.9% y etomidato; y GIV) NaCl a 7.5% y etomidato. Mediciones hemodinamicas fueron obtenidas en cinco momentos: (M0) inicial; (M1) despues del desarrollo del choque hemorragico; (M2) despues de la administracion de soluciones; (M3) 5 minutos despues de la induccion anestesica; (M4) 15 minutos despues de la induccion anestesica. Se hizo el analisis estadistico usando el Student t test y two-way ANOVA. Fueron considerados significativos valores de p menores que 0,05. RESULTADOS: Despues de la instalacion del choque, los dos sueros reestablecieron los estandares hemodinamicos a los valores iniciales. Independiente del anestesico o del solucion utilizada, despues de la induccion anestesica la presion arterial media permanecio inalterada en todos los grupos. La presion venosa central, frecuencia cardiaca, presion capilar pulmonar y el indice de resistencia pulmonar vascular aumentaron significativamente despues de la administracion de cetamina. El indice cardiaco, el indice de resistencia vascular sistemica y el transporte de oxigeno permanecieron estables en todos los grupos. CONCLUSIONES: El etomidato o la cetamina fueron capaces de mantener la estabilidad hemodinamica en los perros que sufrieron choque hemorragico severo y que fueron tratados con NaCl a 0,9% o NaCl a 7,5%.BACKGROUND AND OBJECTIVES Bleeding causing hemorrhagic shock usually requires surgical treatment under general anesthesia. Anesthetic drugs may further compromise hemodynamics. The objective was to compare the hemodynamic effects of ketamine and etomidate during anesthetic induction in dogs submitted to an experimental model of hemorrhagic shock and resuscitation. METHODS Thirty-two mongrel dogs were submitted to a pressure-controlled hemorrhagic shock, resuscitation and anesthetic induction model. After achieving the target pressure of 40 mmHg, they were randomly assigned in two groups according to the resuscitation fluid to be used: NaCl 0.9% (32 mL.kg-1) and NaCl 7.5% (4 mL.kg-1). After volume infusion, these groups were reassigned according to anesthetic drug used: GI) NaCl 0.9% and ketamine; GII) NaCl 7.5% and ketamine; GIII) NaCl 0.9% and etomidate; and GIV) NaCl 7.5% and etomidate. Hemodynamic measurements were obtained at five moments: (M0) baseline; (M1) after bleeding to shock; (M2) after volume expansion; (M3) 5 minutes after anesthetic induction; (M4) 15 minutes after anesthetic induction. Statistical analysis was performed using Student t test and two way ANOVA. Value of p lower than 0.05, was considered significant. RESULTS After shock, both solutions restored hemodynamics to baseline values. Independently of anesthetic agent or expansion solution used, mean arterial pressure remained unaltered for all groups after induction. Central venous pressure, heart rate, pulmonary capillary wedge pressure and pulmonary vascular resistance index increased significantly after ketamine infusion. Cardiac index, systemic vascular resistance index and oxygen transport variables remained stable in all groups. CONCLUSIONS Etomidate or ketamine were able to maintain hemodynamic stability in dogs undergoing severe hemorrhagic shock treated with NaCl 0.9% or NaCl 7.5%.

Inducción anestésica después del tratamiento del choque hemorrágico: estudio experimental eomparando la cetamina y el etomidato

JUSTIFICATIVA Y OBJETIVOS: El sangramiento que conlleva al choque hemorragico generalmente necesita un tratamiento quirurgico bajo anestesia general. A su vez, los anestesicos pueden comprometer mas las condiciones hemodinamicas. El objetivo de este estudio fue el de comparar los efectos hemodinamicos de la cetamina y del etomidato durante la induccion anestesica en perros sometidos a un modelo experimental de choque hemorragico y reanimacion. METODO: Treinta y dos perros mestizos fueron sometidos al choque hemorragico presion-controlada, reanimacion e induccion anestesica. Despues de alcanzar la presion objeto de 40 mmHg ellos fueron divididos aleatoriamente en dos grupos de acuerdo con el liquido usado en la resucitacion: NaCl a 0.9% (32 mL.kg-1) y NaCl a 7,5% (4 mL.kg-1). Despues de la infusion de volumen, esos grupos fueron divididos nuevamente de acuerdo con el anestesico utilizado: GI) NaCl a 0.9% y cetamina; GII) NaCl a 7.5% y cetamina; GIII) NaCl a 0.9% y etomidato; y GIV) NaCl a 7.5% y etomidato. Mediciones hemodinamicas fueron obtenidas en cinco momentos: (M0) inicial; (M1) despues del desarrollo del choque hemorragico; (M2) despues de la administracion de soluciones; (M3) 5 minutos despues de la induccion anestesica; (M4) 15 minutos despues de la induccion anestesica. Se hizo el analisis estadistico usando el Student t test y two-way ANOVA. Fueron considerados significativos valores de p menores que 0,05. RESULTADOS: Despues de la instalacion del choque, los dos sueros reestablecieron los estandares hemodinamicos a los valores iniciales. Independiente del anestesico o del solucion utilizada, despues de la induccion anestesica la presion arterial media permanecio inalterada en todos los grupos. La presion venosa central, frecuencia cardiaca, presion capilar pulmonar y el indice de resistencia pulmonar vascular aumentaron significativamente despues de la administracion de cetamina. El indice cardiaco, el indice de resistencia vascular sistemica y el transporte de oxigeno permanecieron estables en todos los grupos. CONCLUSIONES: El etomidato o la cetamina fueron capaces de mantener la estabilidad hemodinamica en los perros que sufrieron choque hemorragico severo y que fueron tratados con NaCl a 0,9% o NaCl a 7,5%.BACKGROUND AND OBJECTIVES Bleeding causing hemorrhagic shock usually requires surgical treatment under general anesthesia. Anesthetic drugs may further compromise hemodynamics. The objective was to compare the hemodynamic effects of ketamine and etomidate during anesthetic induction in dogs submitted to an experimental model of hemorrhagic shock and resuscitation. METHODS Thirty-two mongrel dogs were submitted to a pressure-controlled hemorrhagic shock, resuscitation and anesthetic induction model. After achieving the target pressure of 40 mmHg, they were randomly assigned in two groups according to the resuscitation fluid to be used: NaCl 0.9% (32 mL.kg-1) and NaCl 7.5% (4 mL.kg-1). After volume infusion, these groups were reassigned according to anesthetic drug used: GI) NaCl 0.9% and ketamine; GII) NaCl 7.5% and ketamine; GIII) NaCl 0.9% and etomidate; and GIV) NaCl 7.5% and etomidate. Hemodynamic measurements were obtained at five moments: (M0) baseline; (M1) after bleeding to shock; (M2) after volume expansion; (M3) 5 minutes after anesthetic induction; (M4) 15 minutes after anesthetic induction. Statistical analysis was performed using Student t test and two way ANOVA. Value of p lower than 0.05, was considered significant. RESULTS After shock, both solutions restored hemodynamics to baseline values. Independently of anesthetic agent or expansion solution used, mean arterial pressure remained unaltered for all groups after induction. Central venous pressure, heart rate, pulmonary capillary wedge pressure and pulmonary vascular resistance index increased significantly after ketamine infusion. Cardiac index, systemic vascular resistance index and oxygen transport variables remained stable in all groups. CONCLUSIONS Etomidate or ketamine were able to maintain hemodynamic stability in dogs undergoing severe hemorrhagic shock treated with NaCl 0.9% or NaCl 7.5%.