الملخص
Muchos factores influyen en la decisión de un plan anestésico para los niños que son portadores de una ECC y van a ser intervenidos con una cirugía no cardíaca, incluyendo: - Hipoxemia y cianosis. - Insuficiencia cardíaca. - Trastornos pulmonares. - Disrritmias cardíacas. - Malformaciones genéticas asociadas. - Coagulopatías. - Cirugías paliativas previas. - Magnitud del procedimiento quirúrgico no cardíaco. - Alteraciones del SNC y periférico. Los niños programados para una cirugía no cardíaca pueden no estar con insuficiencia cardíaca o descompensados en el momento del acto quirúrgico. En estos casos, la atención debe estar dirigida hacia la evaluación de la reserva cardíaca y el estado hemodinámico, porque los gradientes de presión y las resistencias vasculares sistémicas y/o pulmonares pueden afectarse por el acto anestésico-quirúrgico, el cual altera la cantidad y dirección del cortocircuito o la capacidad del corazón para vencer una obstrucción. De esta manera: -Los niveles superficiales de anestesia o la administración de a agonistas aumentan la resistencia vascular sistémica (RVS) y promueven el shunteo en los pulmones. -La administración de vasodilatadores o la anestesia profunda con halogenados ocasionan un shunteo de sangre fuera de los pulmones. -La hipoxia, hipercarbia, acidosis, incremento de la presión media en la vía aérea, estimulación simpática, hipotermia e hipervolemia provocan un shunteo de sangre fuera de los pulmones. -La hiperventilación, al disminuir la RVPulmonar, puede ocasionar un shunteo pulmonar. En cualquiera de los defectos cardíacos, lo más importante es mantener la oxigenación de los tejidos, entendiendo que hay dos tipos de hipoxemia de origen cardíaco: -FSP y cortocircuito derecha-izquierda (Tetralogía de Fallot) -Sin compromiso del FSP pero con una importante mezcla de sangre venosa pulmonar y venosa sistémica (transposición de los grandes vasos). La estrategia general para evitar la hipoxemia durante la inducción o el mantenimiento de la anestesia en los pacientes con FSP es: -Asegurar una hidratación adecuada. -Mantener la presión arterial sistémica. -Minimizar la resistencia vascular pulmonar (RVPulmonar). -Evitar los incrementos bruscos de las demandas de oxígeno, como ocurre con el llanto y los niveles superficiales de anestesia. Y en aquellos pacientes en los que no hay una alteración del FSP pero existe una mezcla importante de la sangre venosa pulmonar con la venosa sistémica...
الموضوعات
Humans , Male , Female , Child, Preschool , Anesthetics, General/pharmacokinetics , Anesthetics, General/therapeutic use , Anesthesia , Heart Defects, Congenital/surgery , Heart Defects, Congenital/classification , Heart Defects, Congenital/complications , Heart Defects, Congenital/diagnosis , Heart Defects, Congenital/etiology , Heart Defects, Congenital/physiopathology , Heart Defects, Congenital/therapy , Hemodynamics , Monitoring, Intraoperative , Arrhythmias, Cardiac , Ebstein Anomaly , Hypoxia , Oxygenation , Postoperative Period , Preoperative Careالملخص
La posibilidad de que un paciente despierte durante el transcurso de una anestesia general es causa de desasosiego para los pacientes y motivo de honda preocupación para el anestesiólogo. Su prevalencia es de 0,2 por ciento a 0,4 por ciento sobre el total de anestesias, siendo mayor en trauma, obstetricia y cirugía cardíaca. El concepto de plano anestésico ha ido cambiando a medida que se conoce la fisiología del SNC y su relación con los anestésicos. Desde la CAM de Eger hasta los actuales conocimientos que permiten discernir diferentes CAM según el estímulo, también se ha avanzado en el rol de los opioides como coadyuvantes de los agentes inhalatorios o intravenosos. De esta manera, en el estado de anestesia se suman dos componentes, siendo uno, la pérdida de conciencia y recuerdo, y el otro, la anulación de la respuesta al estímulo nocivo. Así es que resulta difícil definir anestesia, ya que el espectro de efectos que constituyen ese estado no es la suma de varios componentes, sino la suma de acciones farmacológicas distintas. La medición del efecto hipnótico de las drogas se hace con distintos métodos: Técnica del brazo aislado - Frecuencia de contracciones del tercio inferior del esófago - Variabilidad de la frecuencia cardíaca - Electromiograma espontáneo de superficie - Electroencefalograma - Análisis biespectral - Registro de potenciales evocados - Microtemblor ocular. Las medidas para evitar la ocurrencia del estado de inconciencia parcial se basan en el conocimiento de los efectos farmacológicos de las drogas utilizadas y un cuidadoso criterio clínico que incluye la revisión detallada del circuito anestésico y uso de monitores adecuados.
الموضوعات
Humans , Anesthesia Recovery Period , Anesthesia, General , Consciousness , Mental Recall , Monitoring, Intraoperative , Anesthetics, General/pharmacokinetics , Stress Disorders, Post-Traumatic , Evoked Potentials , Eye Movementsالموضوعات
Humans , Anesthetics, Combined/adverse effects , Anesthetics, Combined/pharmacokinetics , Anesthetics, General/administration & dosage , Anesthetics, General/adverse effects , Anesthetics, General/pharmacokinetics , Anesthesia, General , Drug Interactions , Muscle Relaxants, Central/pharmacokinetics , Anesthesia Recovery Period , Cost-Benefit Analysis , Evaluation Studyالملخص
General anesthesia is defined by reversible unconsciousness, lack of response to noxious stimuli, and amnesia, induced by chemical agents. Mechanisms underlying the anesthetic effect are not known. The most prevalent belief was that anesthetic drugs acted on the lipid cell membranes, based on the correlation between oil solubility and anesthetic potency. Later, it has been proposed that anesthetic agents act on specific proteins of the cellular membrane of neurons. Voltage-gated ionic channels are inhibited by anesthetic agents, being some subtypes more sensitive. Clinical concentration of anesthetic agents inhibit or stimulate excitatory or inhibitory neurotransmitter receptors, respectively. Specific receptor agonists and antagonists modify this effect. Intercellular channels (gap junctions) are also affected by anesthetic agents through direct interaction with some of their protein subunits. Thus, anesthesia would result from combined effects on specific proteins acting on neural cell excitability as well as transmission and propagation of nerve impulses
الموضوعات
Humans , Anesthetics, General/pharmacokinetics , Ion Channels , Neural Conductionالموضوعات
Humans , Anesthetics, General/pharmacokinetics , Ion Channels , Membranes/drug effects , Calcium Channels/drug effects , gamma-Aminobutyric Acid/drug effects , Potassium Channels/drug effects , Receptors, Nicotinic , Receptors, Glutamate/drug effects , Receptors, Glycine/drug effects , Sodium Channels/drug effectsالملخص
The frequency of adverse drug interactions increases disproportionately with the increase in the number of drugs given to patients. It was shown that 40% of patients given 16 drugs experienced an adverse drug interaction, compared with 5% of patients given fewer than 6 drugs. The magnitude of the drug interaction problem increases substantially in anesthetised patients because of: [i] the increased use of multiple drugs in the preoperative and intraoperative periods; and [ii] the growing population of geriatric patients who, in addition to having diminished drug metabolising capacity, are often prescribed multiple medications for concomitant medical illness. Drug interactions with volatile and intravenous anesthetics can be divided into those that are pharmacokinetic and pharmacodynamic in nature. Pharmacokinetic interactions occur when the absorption, distribution, metabolism or excretion of a drug is altered by the coadministration of a second drug. Pharmacodynamic interactions involve a change in the pharmacological effect of a drug as a result of the action of second drug at receptor sites. An interaction between drugs, if not recognised and corrected, can result in decreased drug efficacy or serious toxicity. It is essential that careful scrutiny of the patient's drug history is an integral part of the preoperative assessment. The importance of drug interactions in anesthesia has become increasingly evident for several reasons, including the increased use of multiple drugs in clinical practice and the current medicolegal climate. Anesthetised patients represent a population with a relatively high risk of drug interactions. Patients who are not receiving any drug therapy before admission are likely to receive not less than 6 to 8 drugs during anesthesia for a simple surgical procedure like laparoscopic cholecystectomy. Nevertheless, patients who present for anesthesia frequently receive a surprising number of different drugs. May et al found in the 1970s that patients received an average of 7.9 drugs during their stay in a general hospital, and Cluff et al found that patients given an antibiotic received on average 13 additional drugs. The number of drugs received by comparable patients today is unlikely to be less. Such multiple drug-taking is not confined to hospital patients. Several surveys have shown that, at any one time, 20% of elderly people in the community are taking 3 or more prescribed drugs, and this proportion rises to over 50% for patients referred to a geriatric service. In a review of adverse drug reactions on a medical ward, 22% were found to be the result of drug-drug interactions. The Boston Collaborative Surveillance Drug Program reported that 6.5% [234 of 3600] of adverse reactions were attributable of drug- durg interactions. This survey, which involved 9900 patients and 83200 drug exposures, only monitored patients on medical wards. The potential drug interactions in surgical patients have also been identified. A total of 1825 surgical patients were reviewed and at least 1 drug interaction was found in 17% of patients. The frequency of adverse drug interactions increases disproportionately with the increase in the number of drugs given to patients. It was shown that 40% of patients given 16 drugs experienced an adverse drug interaction, compared with only 5% of patients given fewer than 6 drugs. The incidence of significant drug interactions with general anesthetics is still largely unknown but is probably clinically significant. A complete drug history and clear, accurate and comprehensive drug prescribing and recording documents are essential if such interactions are to be avoided during and after anesthesia. The purpose of this review is to focus on the potentially important interactions with volatile and intravenous anesthetics. Other interactions that might occur between drugs given during anesthesia [e.g. antibiotics and neuromuscular blocking drugs] were considered outside the scope of this review
الموضوعات
Humans , Anesthetics, General/pharmacokinetics , Anesthetics, Inhalation/pharmacokinetics , Sympathomimetics/pharmacokinetics , Hypoglycemic Agents , Bronchodilator Agents , Psychotropic Drugs , Hypnotics and Sedatives , Narcotics , Neuromuscular Blocking Agents , Antineoplastic Agents , Substance-Related Disorders , Contrast Media , Anesthetics, Intravenous/pharmacokinetics , Barbiturates , Benzodiazepines , Propofol , Ketamine , Etomidateالملخص
La realización de la anestesia en obstetricia se diferencia de otras, fundamentalmente porque son dos los seres humanos que están a nuestro cuidado, unidos a través de la placenta. La adecuada elección de las drogas debe basarse en la fisiología de la embarazada, de la placenta y del feto. La presente revisión considera estos tópicos conjuntamente con los factores fisiopatológicos que alteran la farmacocinética de los fármacos utilizados en este período. Combinando ambos conceptos, la fisiología y la farmacocinética alteradas, nos permite inferir el uso racional de medicamentos en el binomio madre-feto, ya sea durante el trabajo de parto, el parto en sí, y en las intervenciones no obstétricas y obstétricas. Los grupos de drogas consideradas son dos : drogas anestésicas y perianestésicas. En el primer grupo se menciona los agentes inductores, ansiolíticos, neurolépticos, morfinosímiles, relajantes musculares periféricos, agentes inhalatorios y anestésicos locales. En el segundo grupo se ha tratado bloqueantes H2, bloqueantes colinérgicos, hipertensores, ocitócicos y depresores del miometrio.