[High frequency jet ventilator - a new approach in the management of anesthesia for pediatric cardiac Magnetic Resonance Imaging: case series]. / Ventilação a jato de alta frequência ­ uma nova abordagem no manejo da anestesia para ressonância magnética em cardiologia pediátrica: série de casos.

BACKGROUND AND OBJECTIVES: Cardiac Magnetic Resonance Imaging (MRI) is a technique used for evaluation of children with congenital heart diseases. General anesthesia ensures immobility, particularly in uncooperative patients. However, chest wall movements can limit good quality scans. Prolonged apnea may be necessary to decrease respiratory motion artefacts, potentially leading to hypoxemia and other adverse events. The use of a high frequency jet ventilator may be a solution avoiding chest wall movements. CASE REPORT: We report four cases of pediatric patients, ASA II, aged between 4 and 15 years-old, scheduled for cardiac MRI. General anesthesia was proposed and parental informed consent was obtained. After general anesthesia was induced, an uncuffed endotracheal tube was inserted. Then, a 7Fr×40 cm catheter was placed through the endotracheal tube. The proximal outlet of the catheter was attached through a connecting tube to a high frequency jet ventilator (Monsoon III®, Acutronic Medical Systems). Good quality MRI images were obtained. At the end of the procedures, we observed increased salivation and increased end-tidal CO2 (60-70 mmHg), in all patients. The patients were extubated after normocapnia was achieved and neuromuscular blockade reversed. Following appropriate recovery time, the four children were discharged home the same day. CONCLUSIONS: This case series demonstrates that the use of a high frequency jet ventilator for cardiac MRI was feasible, safe, providing good quality cardiac imaging and avoiding anesthesia personnel to be inside the hazardous environment of MRI room. Future studies are needed to confirm its safety and efficiency in pediatric patients.

High frequency jet ventilator ‒ a new approach in the management of anesthesia for pediatric cardiac Magnetic Resonance Imaging: case series / Ventilação a jato de alta frequência - uma nova abordagem no manejo da anestesia para ressonância magnética em cardiologia pediátrica: série de casos

Abstract Background and objectives: Cardiac Magnetic Resonance Imaging (MRI) is a technique used for evaluation of children with congenital heart diseases. General anesthesia ensures immobility, particularly in uncooperative patients. However, chest wall movements can limit good quality scans. Prolonged apnea may be necessary to decrease respiratory motion artefacts, potentially leading to hypoxemia and other adverse events. The use of a high frequency jet ventilator may be a solution avoiding chest wall movements. Case report: We report four cases of pediatric patients, ASA II, aged between 4 and 15 years-old, scheduled for cardiac MRI. General anesthesia was proposed and parental informed consent was obtained. After general anesthesia was induced, an uncuffed endotracheal tube was inserted. Then, a 7Fr × 40 cm catheter was placed through the endotracheal tube. The proximal outlet of the catheter was attached through a connecting tube to a high frequency jet ventilator (Monsoon III®, Acutronic Medical Systems). Good quality MRI images were obtained. At the end of the procedures, we observed increased salivation and increased end-tidal CO2 (60-70 mmHg), in all patients. The patients were extubated after normocapnia was achieved and neuromuscular blockade reversed. Following appropriate recovery time, the four children were discharged home the same day. Conclusions: This case series demonstrates that the use of a high frequency jet ventilator for cardiac MRI was feasible, safe, providing good quality cardiac imaging and avoiding anesthesia personnel to be inside the hazardous environment of MRI room. Future studies are needed to confirm its safety and efficiency in pediatric patients.

Resumo Justificativa e objetivos: A ressonância magnética (RM) cardíaca é uma técnica usada na avaliação de crianças com cardiopatias congênitas. A anestesia geral garante imobilidade, especialmente em pacientes não cooperadores, porém os movimentos da parede torácica podem limitar a boa qualidade dos exames. A apneia prolongada pode ser necessária para diminuir os artefatos do movimento respiratório, potencialmente levando à hipoxemia e outros eventos adversos. O uso de ventilação a jato de alta frequência pode ser uma solução para evitar os movimentos da parede torácica. Relato de caso: Relatamos quatro casos de pacientes pediátricos, ASA II, entre 4-15 anos, programados para ressonância magnética cardíaca. Uma anestesia geral foi proposta e assinaturas em termo de consentimento livre e esclarecido foram obtidas dos pais. Após a indução da anestesia geral, um tubo endotraqueal sem balonete foi inserido. Em seguida, um cateter de 7Fr × 40 cm foi inserido através do tubo endotraqueal. A saída proximal do cateter foi conectada, mediante um tubo conector, a um sistema de ventilação a jato de alta frequência (Monsoon III®, Acutronic Medical Systems). Imagens de ressonância magnética de boa qualidade foram obtidas. No fim dos procedimentos, observamos aumento tanto de salivação quanto de CO2 expirado (60-70 mmHg) em todos os pacientes. Os pacientes foram extubados após a obtenção de normocapnia e reversão do bloqueio neuromuscular. Após o tempo de recuperação apropriado, as quatro crianças receberam alta no mesmo dia. Conclusões: Esta série de casos demonstra que o uso de um sistema de ventilação a jato de alta frequência para ressonância magnética cardíaca é viável e seguro, além de fornecer imagens cardíacas de boa qualidade e evitar a presença da equipe de anestesia dentro do ambiente de risco da sala de ressonância magnética. Estudos futuros são necessários para confirmar sua segurança e eficiência em pacientes pediátricos.

Ventilación jet durante microcirugía de múltiples mixomas laríngeos en paciente con vía respiratoria anatómicamente difícil / Jet ventilation during microsurgery of multiple laryngeal myxomas in a patient with anatomically difficult respiratory airway

Introducción: La microcirugía de laringe incluye el dilema de un campo quirúrgico que coincide espacialmente con el del acceso a la vía respiratoria del paciente. Los mixomas, sobre todo numerosos y supra-infraglóticos, representan un reto terapéutico. Si aunado a este hecho, el paciente presenta una vía respiratoria anatómicamente difícil, la fórmula de la catástrofe sólo precisa mezclarlos con un plan de ventilación convencional. En este caso, la ventilación jet puede ser la alternativa para evitar una situación de desastre. Objetivo: Describir la secuencia de hechos y los resultados al aplicar por primera vez en el país la ventilación jet vía transcricotiroidea. Caso clínico: Ante el fracaso previo de una intervención mediante un método tradicional de ventilación, en una segunda intención para exéresis de múltiples mixomas laríngeos en una paciente con vía respiratoria anatómicamente difícil, después de obtener su consentimiento informado, se procedió a anestesiar y obtener un acceso transcricotiroideo a la vía respiratoria, para ventilar con flujos jet a través de un trocar 16G. La intervención, pensada para 15 min, se extendió durante 90 sin complicaciones ventilatorias o de oxigenación. La paciente fue dada de alta sin secuelas. Conclusiones: Aplicar ventilación jet vía transcricotiroidea fue oportuno, seguro y efectivo. Las complicaciones cardiovasculares menores fueron fácilmente controlables. Se usó por primera vez la ventilación jet transcricotiroidea en el país. Este resultado estimula la asimilación de las tecnologías de ventilación jet en contextos electivos o emergentes, como el desafío de una vía respiratoria anatómicamente difícil(AU)

Introduction: The larynx microsurgery involves the dilemma of a surgical field that coincides spatially with that of access to the patient's airway. Myxomas, especially numerous and supra/subglottic, represent a therapeutic challenge. If together with this fact, the patient presents an anatomically difficult airway, the formula for the catastrophe just needs to mix both with a conventional ventilation plan. In this case, jet ventilation can be the choice to avoid a disaster situation. Objective: To describe the sequence of events and the outcomes when transcricotyroid jet ventilation was applied for the first time in the country. Clinical case: In the face of previous failure of an intervention using a traditional method of ventilation, in a second intention for exeresis of multiple laryngeal myxomas in a patient with anatomically difficult airway, after obtaining her informed consent, we proceeded to anesthetize to obtain a transcricothyroid access to the respiratory tract, to ventilate with jet flows through a 16G trocar. The intervention, planned for 15 min, was extended for 90 minutes without ventilatory or oxygenation complications. The patient was discharged without sequelae. Conclusions: Transcricotyroid jet ventilation was timely, safe and effective. Minor cardiovascular complications were easily controllable. Transcricotyroid jet ventilation was used for the first time in the country. This outcome stimulates the assimilation of jet ventilation technologies in elective or emerging contexts, such as the challenge of an anatomically difficult airway(AU)

Seguridad y efectividad de la ventilación a chorro con frecuencias ventilatorias convencionales para microcirugía laríngea electiva / Safety and effectiveness of jet ventilation with conventional ventilatory frequencies for elective microlaryngeal surgery

Introducción: La ventilación al paciente durante la microcirugía laríngea confronta varios problemas. La ventilación a chorro tipo jet con frecuencias ventilatorias convencionales permite usar catéteres endotraqueales de pequeño diámetro para aportar volúmenes adecuados de oxígeno y proporciona mejores condiciones operatorias que el método tradicional. Objetivo: Evaluar la seguridad y efectividad de la ventilación jet con frecuencias ventilatorias convencionales para microcirugía laríngea electiva en comparación con la ventilación convencional. Métodos: Se realizó un estudio comparativo, a simple ciego, aleatorizado y paralelo. Se trabajó con un prototipo de dispositivo de ventilación jet con permiso de uso excepcional en seres humanos (autorización excepcional No: 004/17 para realización de estudio piloto, con fecha 2 de agosto de 2017, conferido por el CECMED). Se utilizó un grupo estudio de 45 pacientes (grupo E) y se comparó con un grupo control (grupo C) de 15 pacientes ventilados mediante el método tradicional. Resultados: La oxigenación resultó superior dentro del grupo E. El grupo C requirió eventualmente de extubación, apnea transitoria y reintubación, lo que repercutió en contra de la integridad anatomofisiológica de los pacientes, del campo operatorio y la docencia. Fue evidente una mayor estabilidad hemodinámica entre los sujetos del grupo E. Las presiones intrapulmonares producidas por la ventilación jet no provocaron lesiones ni repercusión clínica evidentes. Conclusiones: Aplicar la ventilación a chorro con frecuencias ventilatorias convencionales fue seguro y efectivo. Por primera vez se obtienen experiencias de utilización de un método de ventilación jet en el país. El grupo en el que se aplicó la ventilación convencional sufrió complicaciones más frecuentes y peligrosas. Es necesario asimilar las tecnologías de ventilación jet para elevar la calidad de la atención médica en tiempos de paz, de guerra o desastres, en contextos electivos, o emergentes como el desafío de una vía respiratoria difícil(AU)

Introduction: Ventilation to the patient during microlaryngeal surgery confronts several problems. Jet ventilation with conventional ventilatory frequencies allows the use of small diameter endotracheal catheters to provide adequate oxygen volumes and provide better operating conditions than the traditional method. Objective: To evaluate the safety and effectiveness of jet ventilation with conventional ventilatory frequencies for elective microlaryngeal surgery in comparison to conventional ventilation. Methods: A comparative, single-blind, randomized and parallel study was performed. It was used a prototype of jet ventilation device with an exceptional use permit in humans (exceptional authorization No: 004/17 for conducting a pilot study, dated August 2, 2017, conferred by the CECMED). A study group of 45 patients (group E) was used and compared with a control group (group C) of 15 patients using the traditional ventilation method. Results: Oxygenation was higher in group E. Group C eventually required extubation, transitory apnea and reintubation, which impacted against the anatomophysiological integrity of patients, the operative field and teaching. A greater hemodynamic stability was evident among the subjects of group E. The intrapulmonary pressures produced by jet ventilation did not cause obvious injuries or clinical repercussions. Conclusions: Applying jet ventilation with conventional ventilatory frequencies was safe and effective. For the first time, experiences of using a jet ventilation method in the country were obtained. The group in which conventional ventilation was applied suffered more frequent and dangerous complications. It is necessary to assimilate jet ventilation´s technologies to raise the quality of medical attention in times of peace, war or disasters, in elective or emerging contexts as the challenge of a difficult airway(AU)

Rescue high-frequency jet ventilation versus conventional ventilation for severe pulmonary dysfunction in preterm infants.

BACKGROUND: Chronic lung disease (CLD) is a major cause of mortality and morbidity in very low birth weight infants despite increased use of antenatal steroids and surfactant therapy. Ventilator injury and oxygen toxicity are thought to be important factors in the pathogenesis of chronic pulmonary disease. Evidence from animal studies and from adult human studies indicates that high-frequency jet ventilation may reduce the severity of lung injury associated with mechanical ventilation. OBJECTIVES: To compare use of high-frequency jet ventilation (HFJV) versus conventional ventilation (CV) in preterm infants with severe pulmonary dysfunction.Subgroup analyses include the following.• Trials with and without surfactant replacement therapy.• Trials with and without strategies to maintain lung volume.• Trials with infants of different gestational ages and birth weights (specific subgroups to include < 28 weeks' gestation and < 1000 grams).• Trials with and without adequate humidification of inspired gases. SEARCH METHODS: The original search included MEDLINE (1966 to August 2005), the Cochrane Central Register of Controlled Trials (CENTRAL; 2005, Issue 3) and EMBASE (1988 to August 2005). We also obtained information from experts in the field and checked cross-references. We updated the electronic search in June 2013 and again in June 2015. SELECTION CRITERIA: We included in this systematic review randomised and quasi-randomised controlled trials of rescue high-frequency jet ventilation versus conventional ventilation in preterm infants born at less than 35 weeks' gestation or with birth weight less than 2000 grams in respiratory distress. DATA COLLECTION AND ANALYSIS: We used standard methods of the Cochrane Neonatal Review Group, including independent trial assessment and data extraction. We analysed data using risk ratios (RRs) and risk differences (RDs). MAIN RESULTS: We included only one trial in the review. Keszler 1991 randomly assigned 166 preterm infants; reported data on 144 infants; and permitted cross-over to the alternate treatment if initial treatment failed. Investigators found no statistically significant differences in overall mortality (including survival after cross-over) between the two groups (RR 1.07, 95% confidence interval (CI) 0.67 to 1.72). In a secondary analysis of infants up to the time of cross-over, rescue treatment with HFJV was associated with lower mortality (RR 0.66, 95% CI 0.45 to 0.97). Researchers reported no significant differences in the incidence of CLD among survivors at 28 days of age, nor in the incidence of intraventricular haemorrhage, new air leaks, airway obstruction and necrotising tracheobronchitis. AUTHORS' CONCLUSIONS: Study authors reported no significant differences in overall mortality between rescue high-frequency jet ventilation and conventional ventilation and presented highly imprecise results for important adverse effects such as intraventricular haemorrhage, new air leaks, airway obstruction and necrotising tracheobronchitis.The overall quality of evidence is affected by limitations in trial design and by imprecision due to the small number of infants in the included study. Existing evidence does not support the use of high-frequency jet ventilation as rescue therapy in preterm infants.Studies that target populations at greatest risk and that have sufficient power to assess important outcomes are needed. These trials should incorporate long-term pulmonary and neurodevelopmental outcomes.

The influence of hemorrhagic shock on ventilation through needle cricothyroidotomy in pigs.

BACKGROUND: The aim of this study was to examine the effects of controlled hemorrhage and shock on oxygenation and ventilation using needle cricothyroidotomy and jet ventilation in an animal model. METHODS: Twenty-four male pigs were randomly allocated into 4 groups: SHOCK (animals in hemorrhagic shock only), CRICH (animals that underwent needle cricothyroidotomy only), SHOCK+CRICH (animals in hemorrhagic shock + needle cricothyroidotomy), and SHAM (anesthetized animals submitted to surgical preparation only). All animals were surgically prepared and were observed for a period of 40 minutes (T0 - T40). Hemodynamic and blood gas variables were compared using analysis of variance and Bonferroni post hoc testing at a level of significance of 95%. RESULTS: CRICH and SHOCK+CRICH developed respiratory acidosis, with a progressive decrease of arterial pH after T20, and they presented a significant increase of PaCO(2) levels after T10, when compared with SHAM and SHOCK (P < .001). When SHOCK+CRICH was compared with CRICH, it presented a larger increase of PaCO(2) after T10 (P = .036) and an even more significant increase after T20 (P = .009). CONCLUSION: Hemorrhagic shock anticipated and intensified the retention of carbon dioxide and respiratory acidosis during manual jet ventilation through needle cricothyroidotomy in comparison with animals with jet ventilation but without shock. The results found in this work should be considered in future protocols for the assistance of victims of trauma in prehospital settings.

Ventilación mecánica: [revisión] / Mechanical ventilation: [review]

La ventilación mecánica (VM) es un recurso terapéutico de soporte vital, que ha contribuido decisivamente en mejorar la sobrevida de los pacientes en estado crítico, sobre todo aquellos que sufren insuficiencia respiratoria aguda (IRA). La mejor comprensión de los procesos fisiopatológicos y los recientes avances informáticos que han mejorado los ventiladores mecánicos, facilitan el tratamiento de estos pacientes. Este artículo tiene como objetivo la descripción en forma práctica de la VM, involucrando una explicación del mismo ventilador, sus componentes, sus funciones, así como los efectos fisiológicos que se producen al someter a un paciente a la VM. También se reseñan las indicaciones, cómo y por qué programar los diferentes parámetros del soporte, incluyendo una explicación grafica de los modos ventilatorios más frecuentemente usados y la monitorización multimodal que nos permite optimizar el manejo en forma individual para cada situación; además se detallan las complicaciones más frecuentes y en forma sucinta se describe el desteteo descontinuación de la VM. Por último, se revisan los pormenores del transporte de los pacientes con soporte ventilatorio y se repasan los medicamentos más usados en la sedación y analgesia.

Mechanical ventilation (MV) is a therapeutic resource of life support, which has been instrumental in improving survival in critically ill patients, especially those suffering acute respiratory failure. A better understanding of pathophysiological phenomena and recent advances in technology had facilitated therapy for such patients. The aim of this paper is to describe MV using a practical approach, explaining how a mechanical ventilator works, together with its components and its functioning mechanisms, also considering the physiological effects that occur when we put a patient in MV.

Ventilación mecánica / Mechanical Ventilation

La ventilación mecánica (VM) es un recurso terapéutico de soporte vital, que ha contribuido decisivamente en mejorar la sobrevida de los pacientes en estado crítico, sobre todo aquellos que sufren insuficiencia respiratoria aguda (IRA). La mejor comprensión de los procesos fisiopatológicos y los recientes avances informáticos que han mejorado los ventiladores mecánicos, facilitan el tratamiento de estos pacientes. Este artículo tiene como objetivo la descripción en forma práctica de la VM, involucrando una explicación del mismo ventilador, sus componentes, sus funciones, así como los efectos fisiológicos que se producen al someter a un paciente a la VM. También se reseñan las indicaciones, cómo y por qué programar los diferentes parámetros del soporte, incluyendo una explicación grafica de los modos ventilatorios más frecuentemente usados y la monitorización multimodal que nos permite optimizar el manejo en forma individual para cada situación; además se detallan las complicaciones más frecuentes y en forma sucinta se describe el desteteo descontinuación de la VM. Por último, se revisan los pormenores del transporte de los pacientes con soporte ventilatorio y se repasan los medicamentos más usados en la sedación y analgesia.

Mechanical ventilation (MV) is a therapeutic resource of life support, which has been instrumental in improving survival in critically ill patients, especially those suffering acute respiratory failure. A better understanding of pathophysiological phenomena and recent advances in technology had facilitated therapy for such patients. The aim of this paper is to describe MV using a practical approach, explaining how a mechanical ventilator works, together with its components and its functioning mechanisms, also considering the physiological effects that occur when we put a patient in MV.

Manejo de la vía aérea en trasplante de tráquea / Managing of the airway in transplant of trachea

A pesar de los grandes avances en cirugía de resección traqueal y en dispositivos como las endoprótesis, existen pacientes en quienes dichas técnicas no son viables debido al compromiso tan extenso de su estenosis; por lo tanto, su problema no se ha podido resolver alterando la calidad de vida y muchas veces poniendo en riesgo la vida de los pacientes, secundario a una obstrucción de la vía aérea. A continuación, se describe la experiencia del grupo de la Universidad de Antioquia y el Hospital Universitario San Vicente de Paúl, en el manejo de la vía aérea durante el transplante de tráquea realizado a 5 pacientes en la institución, ya que dicho procedimiento se convierte en un reto para el anestesiólogo por compartir el campo quirúrgico con el cirujano. Gracias al entrenamiento previo en cadáveres y en modelos experimentales animales y al trabajo multidisciplinario llevado a cabo, es que se llega a mostrar buenos resultados.

[The impact of mechanical ventilation strategies that minimize atelectrauma in an experimental model of acute lung injury]. / O impacto de estratégias de ventilação mecânica que minimizam o atelectrauma em um modelo experimental de lesão pulmonar aguda.

OBJECTIVE: To evaluate whether ventilation strategies that target alveolar stabilization and prevention of atelectrauma would be associated with more favorable physiologic outcomes in a combined model of acute lung injury. METHODS: Thirty-nine rabbits were instrumented and ventilated with FiO(2) of 1.0. Combined lung injury was induced by an infusion of lipopolysaccharide and tracheal saline lavage. Animals were randomized to receive conventional ventilation with tidal volume of 10 ml/kg, PEEP of 4 cm H(2)O; conventional ventilation with surfactant (Infasurf, 3 mg/kg IT); partial liquid ventilation (18 ml/kg of perflubron IT); or high-frequency oscillatory ventilation with mean airway pressure of 14 cm H(2)O and frequency of 4 Hz. Uninjured ventilated animals served as controls. Conventional ventilation with surfactant, partial liquid ventilation and control groups were ventilated with settings identical to the conventional ventilation group. Animals were studied for 4 hours, during which serial blood gas measurements were obtained. After sacrifice, lungs were harvested for injury grading by a microscopic lung injury score and measurement of 4-hydroxy-nonenal, a marker of lipid peroxidation. RESULTS: Conventional ventilation resulted in hypoxia and greater evidence of lung injury. Animals treated with partial liquid ventilation, high-frequency oscillatory ventilation or conventional ventilation with surfactant had adequate oxygenation, but conventional ventilation with surfactant resulted in higher lung injury scores and increased pulmonary oxidative damage. CONCLUSION: Strategies that minimize atelectrauma (partial liquid ventilation and high-frequency oscillatory ventilation) are associated with adequate oxygenation and attenuated lung injury. Surfactant improves oxygenation in comparison to conventional ventilation alone but resulted in increased injury, presumably because the inadequately low PEEP was insufficient to stabilize the alveoli during expiration.

O impacto de estratégias de ventilação mecânica que minimizam o atelectrauma em um modelo experimental de lesão pulmonar aguda / The impact of mechanical ventilation strategies that minimize atelectrauma in an experimental model of acute lung injury

OBJETIVO: Avaliar se estratégias ventilatórias que buscam a estabilização alveolar e a prevenção do atelectrauma estão associadas a desfechos fisiológicos mais favoráveis em um modelo experimental de lesão pulmonar aguda combinada. MÉTODOS: Trinta e nove coelhos foram instrumentados e ventilados com uma fração inspirada de oxigênio (FiO2) de 1,0. A lesão pulmonar foi induzida pela infusão venosa de lipopolissacarídeo de E. coli e por repetidas lavagens traqueais com solução salina. Os animais foram randomizados a receber ventilação mecânica convencional com volume corrente de 10 ml/kg, pressão expiratória final (PEEP) de 4 cm H2O; ventilação mecânica convencional com surfactante (Infasurf, 3 mg/kg, ET); ventilação líquida parcial (18 ml/kg de perflubron, ET); ou ventilação oscilatória de alta freqüência, com pressão média de via aérea de 14 cm H2O e freqüência de 10 Hz. Animais sadios submetidos a instrumentação e ventilação convencional serviram como controles. Os grupos ventilação mecânica convencional com surfactante, ventilação líquida parcial e controle foram ventilados com parâmetros idênticos ao grupo ventilação mecânica convencional. Os animais foram estudados por 4 horas, durante as quais gasometrias arteriais foram obtidas a cada 30 minutos. Após o sacrifício, os pulmões foram retirados para graduação de lesão através de um escore de dano histológico e dosagem de 4-hidroxi-nonenal, um marcador de peroxidação lipídica. RESULTADOS: A ventilação mecânica convencional resultou em hipoxemia e lesão pulmonar significativa. Animais tratados com ventilação líquida parcial, ventilação oscilatória de alta freqüência ou ventilação mecânica convencional com surfactante apresentaram oxigenação adequada, mas a ventilação mecânica convencional com surfactante resultou em escores de lesão pulmonar mais elevados e maior dano oxidativo. CONCLUSÕES: Estratégias que minimizam o atelectrauma (ventilação mecânica convencional e ventilação oscilatória de alta freqüência) estão associadas a oxigenação adequada e atenuação da lesão pulmonar. A reposição de surfactante melhora a oxigenação em comparação com a ventilação mecânica convencional, mas resulta em lesão pulmonar aumentada, presumivelmente porque o PEEP inadequadamente baixo foi insuficiente para estabilizar os alvéolos durante a expiração.

[A case of "ventilation difficulty-intubation difficulty" solved with transtracheal jet ventilation]. / Un caso de "dificultad de ventilación-dificultad de intubación" resuelto con ventilación jet transtraqueal.

A 56-year-old man recovering from a glossectomy and radical neck dissection presented severe oral bleeding, tracheal deviation with an asphyxiating hematoma and cyanosis. When 2 attempts at orotracheal intubation with the patient awake failed, transtracheal jet ventilation was used temporarily until a definitive airway could be established. Transtracheal jet ventilation is highly useful for managing an airway and maintaining gas exchange in life-threatening situations in which intubation and ventilation has become impossible, yet it is rarely used for that purpose. An easy, fast procedure that has not been widely used in Spain, this technique provides effective ventilation and oxygen while a definitive resolution of the emergency is sought.

Diagnóstico y orientación terapéutica de la vía aérea difícil / Diagnosis and therapeutic approach to a difficult respiratory tract

El control de la respiración del paciente quirúrgico es una tarea de rutina del médico anestesiólogo e implica el uso de distintas técnicas de mantenimiento de la ventilación en forma espontánea, asistida o controlada. Cualquiera sea el tipo de ventilación elegida, siempre debe realizarse una cuidadosa evaluación de la vía aérea para decidir la terapéutica a seguir. Existen distintos métodos para determinar el grado de dificultad en el manejo de la vía aérea del paciente quirúrgico. Aún así, se presentan casos en que no se puede detectar el problema con antelación, según el método empleado a tal efecto. Esta es una de las causas por las que la mayor parte de las complicaciones fatales en anestesia se deban a un inadecuado manejo de la vía aérea. El propósito de este artículo es repasar los elementos diagnósticos, a fin de reconocer una vía aérea dificultosa, y orientar la toma de decisiones de las técnicas a elegir para asegurar su manejo en pacientes con probabilidades de presentar dificultades.

Diagnóstico y orientación terapéutica de la vía aérea difícil / Diagnosis and therapeutic approach to a difficult respiratory tract

El control de la respiración del paciente quirúrgico es una tarea de rutina del médico anestesiólogo e implica el uso de distintas técnicas de mantenimiento de la ventilación en forma espontánea, asistida o controlada. Cualquiera sea el tipo de ventilación elegida, siempre debe realizarse una cuidadosa evaluación de la vía aérea para decidir la terapéutica a seguir. Existen distintos métodos para determinar el grado de dificultad en el manejo de la vía aérea del paciente quirúrgico. Aún así, se presentan casos en que no se puede detectar el problema con antelación, según el método empleado a tal efecto. Esta es una de las causas por las que la mayor parte de las complicaciones fatales en anestesia se deban a un inadecuado manejo de la vía aérea. El propósito de este artículo es repasar los elementos diagnósticos, a fin de reconocer una vía aérea dificultosa, y orientar la toma de decisiones de las técnicas a elegir para asegurar su manejo en pacientes con probabilidades de presentar dificultades. (AU)

Ventilación jet trans traqueal percutanea: experiencia en 21 casos / Per cutaneous trans tracheal jet ventilation: experience in 21 cases

Material y Métodos: Se estudiaron 21 casos durante un período de 2 años, todos los pacientes fueron sometidos a ventilación jet trans traqueal percutánea. En 14 pacientes el procedimiento se realizó para microcirugía laríngea, en 5 casos se utilizó para valorar la vía aérea en pacientes con quemadura por inhalación, en un caso se utilizó por trauma laríngeo y en un caso como medida de urgencia para restablecer la vía aérea en un paciente con fracturas faciales de alto impacto, epistaxis masiva y complicaciones diversas. Resultados: En ningún caso se encontraron complicaciones inherentes al procedimiento. Conclusión: La ventilación jet trans traqueal percutánea es un procedimiento útil y usualmente sin complicaciones

Fisiología aplicaciones y complicaciones de la ventilación jet transtraqueal / Complications applications and physiology of the transtracheal jet ventilation

La Ventilación Jet Transtraqueal (VJTT) sistema de alto flujo de oxígeno, administrado a través de un catéter de grueso calibre, insertado en la membrana cricotiroidea. El objetivo principal es demostrar su utilidad en procedimientos electivos, mediante el mantenimiento de una adecuada oxigenación, ventilación y estabilidad hemodinámica. Veinte pacientes, ASA I o II, mayores de 18 años, programados para intervenciones electivas, menores de 90 minutos. Posterior a la inducción anestésica se inició la VJTT, con controles gasométricos a los 0 y 30 minutos, monitoreo oximétrico, presión arterial, frecuencia y ritmo cardíaco. Los resultados cuantitativos se expresaron en Promedios y Desviación Standard, se aplicó la t de Student. Los datos cualitativos en Porcentajes. La oxigenación fue adecuada en todos los pacientes, manteniendo una PaO2 media de 317 ñ 116,71 mm de Hg y saturación de Oxígeno de 98,78 ñ 0,71 por ciento. Los cambios del pH a los 0 y 30 minutos, mostraron variación significativa, sin importancia clínica. Las presiones arteriales de CO2 se encontraron elevadas en 4 pacientes; en dos acompañadas de un pH disminuido. Las variables hemodinámicas, no se modificaron en el transoperatorio. El 90 por ciento de los pacientes presentaron o no complicaciones leves. Concluimos que la VJTT es un procedimiento seguro, para ser usado en forma electiva; constituye un sistema para la oxigenación y ventilación del paciente, tanto clínico como gasométrico

Inhaled nitric oxide in term infants with hypoxemic respiratory failure.

OBJECTIVE: To determine whether inhaled nitric oxide (NO) administered during conventional mechanical ventilation could produce improvements in oxygenation and reduce the incidence of meeting extracorporeal membrane oxygenation (ECMO) criteria in infants with hypoxemia. DESIGN: Prospective, randomized, controlled trial. Enrolled infants were assigned to conventional treatment with or without adjunctive inhaled NO. Control infants meeting failure criteria (partial pressure of arterial oxygen (PaO2)<80 mm Hg (10.7 kPa)) were allowed to cross over. Caregivers were not masked to group assignment. SETTING: Neonatal intensive care units at the University of Alabama Hospital and the Children's Hospital of Alabama, October 1993 to May 1994. PATIENTS: Newborn infants, both term and near-term, with PaO2 less than 100 mm Hg (13.3 kPa) who were receiving mechanical ventilation with 100% oxygen. Exclusion criteria included major congenital anomalies, diaphragmatic hernia, profound asphyxia, and significant bleeding. INTERVENTIONS: Inhaled NO was initiated in the NO group at a dose of 20 to 40 ppm and advanced stepwise to 80 ppm if PaO2 remained less than 100 mm Hg (13.3 kPa). OUTCOME MEASURES: Primary outcome variables were treatment failure and meeting of ECMO criteria before crossover. Improvement in oxygenation and ultimate use of ECMO or high-frequency oscillatory ventilation were secondary outcome variables. RESULTS: Seventeen neonates with hypoxemia were enrolled; 16 had echocardiographic evidence of pulmonary hypertension, and eight had extrapulmonary shunting. At 1 hour of treatment, two infants in the NO group responded with increases in PaO2 of more than 100 mm Hg (13.3 kPa); after crossover, two had increases in PaO2 of more than 10 mm Hg (1.3 kPa) and one control infant had an increase in PaO2 of more than 10 mm Hg (1.3 kPa). All control infants met failure criteria and crossed over to receive NO; two had increases in PaO2 of more than 10 mm Hg (1.3 kPa) with NO treatment. Despite initial responses, all subjects in both groups eventually met failure criteria. There were no differences between groups in primary outcome variables. CONCLUSIONS: Although inhaled NO produced a transient improvement in oxygenation in some infants, it did not reduce the incidence of meeting ECMO criteria in this population.