RESUMEN
The relationship between cardiac output and anesthetic drugs is important to anesthesiologists, since cardiac output determines the speed with which a drug infused into the bloodstream reaches its target and the intensity of the drug's effect. But rather than focus on how anesthetic drugs affect cardiac output, this narrative review focuses on how changes in cardiac output affect the pharmacokinetics and pharmacodynamics of general anesthetics during the three phases of anesthesia. At induction, an increase in cardiac output shortens both the onset time of propofol for hypnosis and the neuromuscular blocking effect of rapid-acting neuromuscular blockers, favoring the conditions for rapid sequence intubation. During maintenance, changes in cardiac output are followed by opposite changes in the drug plasma concentration of anesthetic drugs. Thus, an increase in cardiac output followed by a decrease in the plasma concentration of the anesthetic could expose the patient to a real risk of intraoperative awakening, which can be avoided by increasing the dose of hypnotic drugs. At emergence, an increase in cardiac output secondary to an increase in pC02 allows for a more rapid recovery from anesthesia. The pC02 can be increased by adding CO2 to the respiratory circuit, lowering the ventilatory rate, or placing the patient on partial rebreathing. Finally, the reversal action of sugammadex for rocuronium-induced neuromuscular block can be shortened by increasing the cardiac output.
La relación entre el gasto cardíaco y los fármacos anestésicos es importante para los anestesiólogos puesto que el gasto cardíaco determina la velocidad con la cual un medicamento que se infunde al torrente sanguíneo llega a su diana y la intensidad del efecto del agente. Pero en lugar de concentrarnos en cómo los fármacos anestésicos afectan el gasto cardíaco, esta revisión narrativa se enfoca en cómo los cambios en el gasto cardíaco afectan la farmacocinética y la farmacodinámica de los agentes anestésicos generales durante las tres fases de la anestesia. En el momento de la inducción, un incremento en el gasto cardíaco acorta tanto el tiempo de inicio del efecto del propofol para la hipnosis como el efecto del bloqueo neuromuscular causado por los bloqueadores neuromusculares de acción rápida, favoreciendo las condiciones para la intubación de secuencia rápida. Durante la fase de mantenimiento, los cambios en el gasto cardíaco vienen seguidos de cambios opuestos en la concentración plasmática del medicamento de los agentes anestésicos. Por lo tanto, un aumento del gasto cardíaco, seguido de una reducción en la concentración plasmática del anestésico, podría exponer al paciente a un riesgo real de despertar intraoperatorio, lo cual puede evitarse aumentando la dosis de los fármacos hipnóticos. En la educción, un aumento en el gasto cardíaco secundario al incremento en el pCO2 permite una recuperación más rápida de la anestesia. El pCO2 puede aumentar agregando CO2 al circuito de la respiración, reduciendo la tasa ventilatoria, o colocando al paciente en re-inhalación parcial. Finalmente, la acción de reversión de sugammadex en caso de bloqueo neuromuscular inducido por rocuronio, puede acortarse aumentando el gasto cardíaco.
RESUMEN
Ultrasound evaluation of diaphragm function allows the detection of diaphragm dysfunction and the adaptation of ventilatory support in patients admitted to intensive care units. The studied patient had a C3 spinal cord injury. Ultrasound evaluation of diaphragm mobility showed that the patient suffered diaphragm dysfunction. A tracheotomy was indicated, and early ventilatory support was initiated. Ultrasound evaluation of diaphragm function in patients with cervical spinal cord injury is a useful and simple technique. It provides fast and reliable data for the diagnosis of respiratory insufficiency of neuromuscular origin.
RESUMEN
Oliguria in the setting of critically ill patients is usually treated by admini-stering fluids and furosemide [1]. Invasive therapies, namely renal replacement therapies (RRT), are reserved for patients in whom less invasive measures have failed [2], especially if acute pulmonary oedema complicates the clinical picture [1]. Intravascular volume depletion elicits a kidney response consisting of augmented sodium retention at Henle's loop and water at the collecting tubules. In such conditions, loop diuretics such as furosemide would be less effective to improve diuresis and water loss than osmotic diuretics such as mannitol [3, 4]. This case report aims to highlight the utility of the assessment of the glomerular and tubular functions to identify an ineffective diuretic strategy and to select a successful one, which prevented the use of invasive RRT. A 33-year-old female patient suffering from preeclampsia (gestational age was 35 + 6 weeks) was admitted to our Post-surgical Intensive Care Unit (PICU) after an urgent caesarean section performed under spinal anaesthesia, without further incidents.
Asunto(s)
Oliguria , Preeclampsia , Adulto , Cesárea , Femenino , Furosemida , Humanos , Lactante , Oliguria/terapia , Preeclampsia/terapia , Embarazo , Inhibidores del Simportador de Cloruro Sódico y Cloruro PotásicoRESUMEN
Resumen: La miastenia gravis es una enfermedad autoinmune que puede alterar las capacidades físicas de los pacientes. La timectomía es una de las opciones terapéuticas. Su postoperatorio puede ser complicado por la propia enfermedad o por lesiones intraoperatorias de estructuras nerviosas. Presentamos a una mujer de 66 años intervenida de timectomía por timoma que causa miastenia gravis. Durante la intervención se reseca el nervio frénico izquierdo. En el postoperatorio inmediato presenta insuficiencia respiratoria aguda, por lo que se realiza ecografía pulmonar anodina y ecografía diafragmática que muestra fracción de acortamiento de 10% en el lado derecho y ausencia de contractilidad en el lado izquierdo. La paciente precisó ventilación mecánica no invasiva durante seis días y traqueotomía para avanzar en el destete respiratorio, siendo dada de alta a planta finalmente en respiración espontánea con cánula fenestrada por traqueotomía. La ecografía diafragmática supone una técnica diagnóstica disponible a la cabecera del paciente, útil en situaciones urgentes gracias a su rápida realización y a que complementa la valoración clínica en el diagnóstico de la insuficiencia respiratoria aguda postquirúrgica.
Abstract: Myasthenia gravis is an autoimmune disease that can alter the physical abilities of patients. Thymectomy is one of the therapeutic options. The postoperatory may be complicated by the disease itself or by intraoperative lesions of nerve structures. Case of 66-year-old woman with myasthenia gravis undergoing thymectomy. The left phrenic nerve was resected. In the immediate postoperative period, the patient presented acute respiratory failure. A lung ultrasound is performed, being anodyne. The diaphragmatic ultrasound proved a 10% of thickening fraction on the right side and absence of contractility on the left side. The patient required non-invasive mechanical ventilation for six days, tracheotomy was performed to succeed the respiratory weaning. The patient was transferred to ward in spontaneous ventilation. The diaphragmatic ultrasound is a useful and portable diagnostic technique, mainly in urgent situations due to the rapidity of its implementation. It complements the clinical assessment in the diagnosis of acute postoperative respiratory failure.
Resumo: A miastenia gravis é uma doença auto-imune que pode alterar as capacidades físicas dos pacientes. A timectomia é uma das opções de tratamento. O pós-operatório pode ser complicado pela própria doença ou por lesões intra-operatória de estruturas nervosas. Apresentamos uma mulher de 66 anos submetida a timectomia por timoma que causa miastenia gravis. Durante a cirurgia, o nervo frênico esquerdo é ressecado. No pós-operatório imediato, a paciente apresentou insuficiência respiratória aguda, de modo que foram realizadas uma ultrassonografia pulmonar anódino e ecografia diafragmática, mostrando uma fração de encurtamento de 10% no lado direito e ausência de contratilidade no lado esquerdo. A paciente requeriu de ventilação mecânica não invasiva por 6 dias e a realização de uma traqueotomia para avançar no desmame respiratório, sendo dada de alta da UTI respirando espontâneamente com uma cânula de traqueostomia fenestrada. O ultrassom diafragmático é uma técnica de diagnóstico disponível à beira do leito, útil em situações urgentes devido à rapidez do seu desempenho e que complementa a avaliação clínica no diagnóstico de insuficiência respiratória aguda pós-operatória.
