Duración del ayuno preoperatorio en pacientes con cirugía programada / Duration of preoperative fasting in patients with scheduled surgery

Antecedentes y objetivo: el ayuno preoperatorio disminuye el riesgo de aspiración del contenido gástrico y sus complicaciones. Sin embargo, si es excesivo, favorece la regurgitación y el riesgo de broncoaspiración tras la inducción anestésica, así como alteraciones metabólicas e hidroelectrolíticas. Analizamos su duración, en pacientes con cirugías programadas en un hospital público de agudos. Material y métodos: se encuestó a todos los pacientes mayores de 18 años con cirugías programadas. Se recolectaron datos sobre la prescripción médica de ayuno, la hora de inducción anestésica y personales. El ayuno prescripto se comparó con las recomendaciones de las guías de la AAARBA (Asociación de Anestesia, Analgesia y Reanimación de Buenos Aires). Resultados: se reclutaron 139 pacientes, con una mediana de edad de 48 años (30; 64), 53% femeninos. La mediana del ayuno prescripto fue de 12,5 horas tanto para sólidos como para líquidos. El ayuno para sólidos que realizaron los pacientes tuvo una mediana de 14 horas, la cual resultó significativamente mayor que la prescripción (p < 0,001). En cambio, el ayuno para líquidos tuvo una mediana de 12 horas, no hallándose una diferencia significativa (p = 0,452) con lo prescripto. En comparación con la guía de la AAARBA, el ayuno prescripto excedió la recomendación para sólidos (4,5 h) y para líquidos (10,5 h). El ayuno realizado por el paciente excedió lo prescripto para sólidos (1,5 h), mientras que para líquidos fue inferior (0,5 h). Conclusión: el ayuno preoperatorio prescripto no se adecuó a las recomendaciones actuales. Las horas de ayuno realizadas por el paciente resultaron excesivas. (AU)

Background and objective: preoperative fasting reduces the risk of aspiration of gastric contents and its complications. However, if fasting is excessive, it favours regurgitation and the risk of pulmonary aspiration in patients undergoing general anaesthetic, such as metabolic and electrolyte disorders. We analysed its duration in patients with elective surgeries in public acute care hospital. Material and methodologies: patients over 18 years old with elective surgeries were surveyed. Data about medical fasting indication, time of induction of anaesthesia and personal information was collected. The prescribed fast was compared with the recommendations of the AAARBA (Association of Anaesthesia, Analgesia and Reanimation of Buenos Aires) guidelines. Results: 139 patients were gathered with a median of 48 years old (30; 64), 53% of them were female. Fasting indication median was of 12.5 h for solids and liquids. The fasting made by the patient for solids had a median of 14 h which resulted to be significantly higher to the indication (p < 0.001). By contrast, the fasting for liquids had a median of 12 h which it did not show a significant difference (p = 0.452) with the indication. In comparison with the AAARBA guideline, the fasting indication exceeded the recommendation for solids (4.5 h) and for liquids (10.5 h). The fasting made by the patient exceeded to what was indicated for solids (1.5 h) while for liquids, it was inferior (0.5 h). Conclusion: the indicated preoperative fasting was not adequate to the current recommendations. The hours of fasting made by patient were excessive. (AU)

Fatal pulmonary aspiration during balanced sedation with dexmedetomidine and midazolam: A case report

Recently, balanced sedation has commonly been used during procedural sedation. Dexmedetomidine is known for its relative safety to cause “conscious sedation” with little respiratory depression but has some limitations such as frequent awakening and hemodynamic instability during surgery. To facilitate sedation, a small dose of midazolam can be co-administered rather than escalating the dose of dexmedetomidine, especially in elderly patient. Despite the respiratory safety profile of dexmedetomidine, the overall safety of co-administration has not been clarified. We describe the first case of fatal pulmonary aspiration that developed in an elderly patient during balanced sedation with spinal anesthesia for elective femur fracture surgery.

¿El reflujo gastroesofágico y la aspiración de contenido gástrico están implicados en la etiopatogenia y la progresión de la fibrosis pulmonar idiopática? / Does gastroesophageal reflux and gastric content aspiration have some role in the pathogenesis and progression of Idiopathic Pulmonary Fibrosis?

Resumen El reflujo gastroesofágico (RGE) y la aspiración oculta de contenido digestivo están probablemente implicados en la etiopatogenia y progresión de la fibrosis pulmonar idiopática (FPI). Los mecanismos patogénicos involucrados son la disminución de la distensibilidad pulmonar y el consiguiente aumento de la presión negativa intratorácica durante la inspiración, así como la disminución de los mecanismos de control de la motilidad esofágica o del tono del esfínter esofágico inferior. La prevalencia de RGE y anomalías de la motilidad esofágica están aumentadas en los pacientes con FPI comparado con la población general. Entre los pacientes con FPI, el 67-76% demostraron exposición anormal al contenido ácido en el esófago. Sin embargo, no hubo relación entre la gravedad del RGE y la gravedad de la FPI. Los estudios que han examinado el tratamiento antirreflujo en esta población han sido escasos. Incluso, algunos datos sugieren que el tratamiento antiácido puede ser perjudicial en algunos pacientes con esta condición. Después de analizar toda la evidencia relevante encontrada hasta la fecha, concluimos que no se puede establecer una relación causal entre el RGE, la aspiración del contenido gástrico y la patogénesis de la FPI. Además, existe escasa evidencia clínica que haya examinado el tratamiento antirreflujo en pacientes con fibrosis pulmonar idiopática.

ABSTRACT Gastroesophageal reflux (GERD) and hidden aspiration of gastric contents are probably involved in the pathogenesis and progression of idiopathic pulmonary fibrosis (IPF). The pathological mechanisms involved are decreased pulmonary distensibility and consequent increase of intrathoracic negative pressure during inspiration, as well as decreased control mechanisms of esophageal motility or lower esophageal sphincter. The prevalence of GERD and oesophageal dysmotility was higher in patients with IPF as compared with general population. Among patients with IPF, 67-76% demonstrated abnormal oesophageal acid exposure. However, no relationship was demonstrated between severity of GERD and severity of IPF. Data are scant on outcomes of antireflux treatment in patients with IPF. Actually, some data suggests that antacid treatment may be deleterious in some IPF patients. After analyzing all the relevant evidence found to date, a causal relationship between GERD, gastric content aspiration and IPF pathogenesis cannot be established. There is scant evidence examining antireflux treatment in idiopathic pulmonary fibrosis patients.

Effectiveness of the endotracheal tube cuff on the trachea: physical and mechanical aspects / Eficácia do balonete do tubo endotraqueal sobre a traqueia: aspectos físicos e mecânicos

Introduction: The inflation pressure of the endotracheal tube cuff can cause ischemia of the tracheal mucosa at high pressures; thus, it can cause important tracheal morbidity and tracheal microaspiration of the oropharyngeal secretion, or it can even cause pneumonia associated with mechanical ventilation if the pressure of the cuff is insufficient. Objective: In order to investigate the effectiveness of the RUSCH® 7.5 mm endotracheal tube cuff, this study was designed to investigate the physical and mechanical aspects of the cuff in contact with the trachea. Methods: For this end, we developed an in vitro experimental model to assess the flow of dye (methylene blue) by the inflated cuff on the wall of the artificial material. We also designed an in vivo study with 12 Large White pigs under endotracheal intubation. We instilled the same dye in the oral cavity of the animals, and we analyzed the presence or not of leakage in the trachea after the region of the cuff after their deaths (animal sacrifice). All cuffs were inflated at the pressure of 30 cmH2O. Results: We observed the passage of fluids through the cuff in all in vitro and in vivo experimental models. Conclusion: We conclude that, as well as several other cuff models in the literature, the RUSCH® 7.5 mm tube cuffs are also not able to completely seal the trachea and thus prevent aspiration of oropharyngeal secretions. Other prevention measures should be taken. .

Introdução: A pressão de insuflação do balonete (cuff) do tubo endotraqueal tanto pode causar isquemia de mucosa traqueal em pressões elevadas, e assim ocasionar morbidade traqueal importante, quanto pode causar microaspiração traqueal de secreção de orofaringe ou, ainda, ocasionar pneumonia associada à ventilação mecânica, caso a pressão do balonete seja insuficiente. Objetivo: A fim de investigar a eficácia do balonete do tubo endotraqueal RUSCH® 7,5mm, este estudo foi desenhado para investigar aspectos físicos e mecânicos do balonete em contato com a traqueia. Métodos: Para isto, foi desenvolvido modelo experimental in vitro para avaliar o escoamento de corante (azul de metileno) pelo balonete insuflado na parede de material artificial. Também foi desenhado estudo in vivo com 12 porcos da raça Large-White sob intubação endotraqueal. Foi instilado o mesmo corante na cavidade oral do animal e após óbito (sacrifício do animal) foi analisada a presença ou não de vazamento deste na traqueia pós-região do balonete. Todos os balonetes foram insuflados na pressão de 30 cmH2O. Resultados: Houve passagem de fluidos pelo balonete em todos os modelos experimentais in vitro e in vivo. Conclusão: Podemos concluir que, assim como diversos outros modelos de balonetes na literatura, balonetes do tubo RUSCH® 7,5mm também não são capazes de vedar completamente a traqueia e com isso prevenir aspiração de secreções orofaríngeas. Outras medidas para a prevenção devem ser tomadas. .

Modelo de instilación intra-traqueal de jugo gástrico en la rata: curso temporal de las alteraciones histológicas / Intra-tracheal instillation of gastric juice in the rat: time course of histological changes

Introduction: Aspiration of gastric content is associated with a wide range of clinical conditions (acute lung injury, severe interstitial pneumonia or bronchiolitis obliterans following lung transplantation). Objective: To study the course of histological alterations in a model of intra-tracheal instillation of gastric juice in rats. Methods: Anesthetized rats were euthanized at different times: 4, 12 and 24 hours and 4 and 7 days after intratacheal (IT) instillation of gastric juice. Animals that were not intervened served as controls. The right inferior lobe was studied (H-E) and a histological injury score was given according to a recently published score system. Results: Between 4-24 h an inflammatory-hemorragic pattern with bronchiol-centric distribution was characterized by a large proportion of neutrophils in both alveoli and interstitium, alveolarfluid accumulation, proteinaceous material andfew hyaline membranes. Between 4 and 7 days, mononuclear cells were more prevalent, the hemorrhagic component disappeared, the percentage of abnormal bronchioles was significantly reduced and there was organization of the alveolar infiltrate, with Masson bodies, granulomas and giant cells associated with gastric juice particles. Conclusions: In rats, IT instillation of gastric juice induces diffuse alveolar damage that evolves towards an early granulomatous interstitial pneumonia along with lax fibrous tissue. Knowledge of the temporary course of the pulmonary responses helps to the understanding of the consequences of the several clinical conditions that favor gastric content aspiration.

Introducción: La aspiración de contenido gástrico se asocia con diversas condiciones clínicas (daño pulmonar agudo, neumonía intersticial severa o bronquiolitis obliterante post-trasplante). Objetivo: Estudiar el curso de las alteraciones histológicas en un modelo de instilación intra-traqueal (IT)de jugo gástrico en ratas. Métodos: Ratas anestesiadas recibieron vía ITjugo gástrico de un pool obtenido previamente. Los animales fueron sacrificados a las: 4, 12 y 24 h y 4 y 7 días post-instilación. Animales sin intervención sirvieron como controles. El lóbulo inferior derecho fue estudiado (H-E) para la asignación de un puntaje de daño histológico de acuerdo a un sistema de puntuación recientemente publicado. Resultados: Entre 4-24 h se observó un patrón inflamatorio-hemorrágico de distribución bronquíolo-céntrica, con predominio de neutrófilos intersticiales y alveolares, edema, material proteináceo alveolar y escasas membranas hialinas. Entre los 4 y 7 días, se observó predominio mononuclear y desaparición del componente hemorrágico, se redujo significativamente el porcentaje de bronquíolos afectados y se observó organización del infiltrado inflamatorio, con cuerpos de Masson, granulomas y células gigantes asociadas a partículas del jugo gástrico. Conclusiones: En ratas, la instilación IT de jugo gástrico induce daño alveolar difuso que progresa hacia una neumonía intersticial granulo-matosa temprana con tejido fibroso laxo. El conocimiento del curso de la respuesta pulmonar en este modelo, contribuye a comprender las posibles consecuencias de las condiciones clínicas que favorecen la aspiración de contenido gástrico.

Usefulness of the Simplified Cough Test in Evaluating Cough Reflex Sensitivity as a Screening Test for Silent Aspiration

OBJECTIVE: To assess cough reflex sensitivity using the simplified cough test (SCT) and to evaluate the usefulness of SCT to screen for silent aspiration. METHODS: The healthy control group was divided into two subgroups: the young (n=29, 33.44+/-9.99 years) and the elderly (n=30, 63.66+/-4.37 years). The dysphagic elderly group (n=101, 72.95+/-9.19 years) consisted of patients with dysphagia, who suffered from a disease involving central nervous system (ischemic stroke 47, intracerebral hemorrhage 27, traumatic brain injury 11, encephalitis 5, hypoxic brain damage 3, and Parkinson disease 8). The SCT was performed using the mist of a 1% citric acid from a portable nebulizer. The time from the start of the inhalation to the first cough was measured as the cough latency. All the dysphagic patients underwent the videofluoroscopic swallowing study. RESULTS: The cough latency was more significantly prolonged in the healthy elderly group than in the healthy young group (p<0.001), and in the dysphagic elderly group than in the healthy elderly group (p<0.001). The sensitivity and specificity of SCT were 73.8% and 72.5% for detecting aspiration in the dysphagic patients, and 87.1% and 66.7% for detecting silent aspiration in the aspirated patients. CONCLUSION: Cough latency measured with the SCT reflects the impairment of cough reflex in healthy elderly and dysphasic subjects. The results of this study show that the SCT test can be a valuable method of screening aspiration with or without cough in dysphasic patients.

Effectiveness of milrinone for cardiogenic shock due to massive pulmonary aspiration: a case report / 대한마취과학회지

Pulmonary aspiration of gastric contents is one of the most frightening complications during anesthesia. Although pulmonary aspiration of gastric contents in general surgical patients is not common and resulting long-term morbidity and mortality are rare, severe hypoxemia and other sequelae of pulmonary aspiration continue to be reported. We report a case of massive aspiration of gastric contents during induction of general anesthesia, resulting in cardiac arrest due to severe pulmonary hypertension and myocardial infarction. Sustained cardiac arrest and shock that did not respond the conventional resuscitation was successfully treated using milrinone. The patient was discharged without complications in 20 days.

Gastric contents in respiratory tract a diagnostic dilemma at autopsy.

Gastric contents in the respiratory tract are commonly found at postmortem in acute alcoholism, occasionally during a fit of epilepsy and in dead bodies that have started decomposing. Quite infrequently it may be found in fresh bodies that have undergone sudden unexpected and unattended death leading to a dilemma as to the real cause of death with dearth of any other substantial evidence. Dead body of a 36-year-old lady was brought for post-mortem examination with history of unattended and unexpected death while taking bath after her afternoon meal. On gross and histopathological examination, there was no significant finding in the cardiovascular system but respiratory tract contained gastric contents with histopathology confirming vegetable matter in the terminal bronchioles. The conflicting literature on the difference between antemortem aspiration and postmortem spill of gastric contents into the respiratory tract led to a dilemma as to the real cause of death in present case. Dilemmas of the case with difficulties in diagnosis are being presented herewith.