Pulmonary strain and end-expiratory lung volume during apnea test: a comparative analysis using electrical impedance tomography / Stress pulmonar y volumen pulmonar de fin de es piración durante el test de apnea: estudio compara tivo utilizando tomografía por impedancia eléctrica

Abstract The apnea test, employed for brain death assessment, aims to demonstrate the absence of respiratory drive due to hypercapnia. The tracheal oxygen insufflation apnea test mode (I-AT) involves disconnecting the pa tient from invasive mechanical ventilation (iMV) for ap proximately 8 minutes while maintaining oxygenation. This test supports the diagnosis of brain death based on a specified increase in PaCO2. Common complications include hypoxemia and hemodynamic instability, and lung collapse-induced reduction in end-expiratory lung volume (EELV). In our case series utilizing electrical impedance to mography (EIT), we observed that continuous positive airway pressure during the apnea test (CPAP-AT) effec tively mitigated lung collapse. This resulted in improved pulmonary strain compared to the disconnection of iMV. These findings suggest the potential benefits of routine CPAP-AT, particularly for potential lung donors, emphasizing the relevance of our study in providing quantitative insights into EELV loss and its association with pulmonary strain and potential lung injury.

Resumen La prueba de apnea es una técnica diagnóstica am pliamente utilizada para la evaluación de la muerte cerebral, con el objetivo de demostrar la ausencia de impulso respiratorio debido a la hipercapnia. La variante de la prueba de apnea con insuflación de oxígeno traqueal (I-AT) implica desconectar al pacien te de la ventilación mecánica invasiva (iVM) durante aproximadamente 8 minutos, manteniendo la oxigena ción mediante un catéter de insuflación. Esta prueba respalda el diagnóstico de muerte cerebral cuando se determina un aumento de la PaCO2 superior a 20 mmHg en comparación con el valor inicial o un nivel de PaCO2 superior a 60 mmHg al final de la prueba. En nuestra serie de casos, la implementación de la tomografía de impedancia eléctrica (EIT) reveló que la prueba de apnea con presión positiva continua (CPAP-AT) mitiga eficazmente el colapso pulmonar. Este enfo que resulta en una mejora en la tensión pulmonar en comparación con la desconexión de iMV, demostrando su relevancia en el contexto de potenciales donantes de pulmones.

Bronchoscopy-guided percutaneous tracheostomy during the COVID-19 pandemic.

BACKGROUND: Assessment of the efficacy and complications associated with performing bronchoscopy-guided percutaneous tracheostomy in COVID-19 and non-COVID-19 patients. METHODS: Prospective observational study conducted between March of 2020 and February of 2022. All adult patients who underwent elective bronchoscopy-guided percutaneous tracheostomy were included. The efficacy of the procedure was evaluated based either on the success rate in the execution or on the need for conversion to open technique. Percutaneous tracheostomy-related complications were registered during the procedure. We performed 6-month follow-up for identifying late complications. RESULTS: During the study period, 312 bronchoscopy-guided percutaneous tracheostomies were analyzed. One hundred and eighty-three were performed in COVID-19 patients and 129 among non-COVID-19 patients. Overall, 64.1% (200) of patients were male, with a median age of 66 (interquartile range 54-74), and 65% (205) presented at least 1 comorbidity. Overall, oxygen desaturation was the main complication observed (20.8% [65]), being more frequent in the COVID-19 group occurring in 27.3% (50) with a statistically significant difference versus the non-COVID-19 patients' group (11.6% [15]); P < .01). Major complications such as hypotension, arrhythmias, and pneumothorax were more frequently observed among COVID-19 patients as well but with no significant differences. Percutaneous tracheostomy could be executed quickly and satisfactorily in all the patients with no need for conversion to the open technique. Likewise, no suspension of the procedure was required in any case. During 6-month follow-up, we found an incidence of 0.96% (n = 3) late complications, 2 tracheal granulomas, and 1 ostomal infection. CONCLUSION: Bronchoscopy-guided percutaneous tracheostomy can be considered an effective and safe procedure in COVID-19 patients. Nevertheless, it is highly remarkable that in the series under study, a great number of COVID-19 patients presented oxygen desaturation during the procedure.

Síndrome de asma crítico con soporte de oxigenación por membrana extracorpórea / Critical asthma syndrome with extracorporeal membrane oxygenation support

Resumen El síndrome de asma crítico es una emergencia médica que amenaza la vida y de no instaurar un tratamiento urgente, progresa a un estado de hipoxia irreversible o paro cardiorrespiratorio. La ventilación mecánica invasiva constituye uno de los pilares terapéuticos, sin embargo, también puede desarrollar injuria pulmonar por barotrauma. En ese contexto, el uso de oxigenación por membrana extracorpórea (ECMO) supone una estrategia adicional para mejorar el intercambio gaseoso y reducir el daño inducido por la ventilación mecánica. Se presenta el caso de una paciente con síndrome de asma crítico que requirió ECMO por barotrauma grave.

Abstract Critical asthma syndrome is a life-threatening medical condition that can lead to irreversible hypoxia or cardiorespiratory arrest. Invasive mechanical ventilation is one of the therapeutic pillars, however, it can also develop ventilator-induced lung injury. For this reason, the use of extracorporeal membrane oxygenation (ECMO) could be an additional strategy to improve gas exchange and reduce damage induced by mechanical ventilation. We present the case of a patient with critical asthma syndrome who required ECMO due to severe barotrauma.

[Oxygenation with extracorporeal membrane in obstructive shock secondary to lymphoproliferative disease]. / Membrana de circulación extracorpórea en shock obstructivo secundario a enfermedad linfoproliferativa.

The arteriovenous extracorporeal membrane is used in patients with hemodynamic and respiratory failure, unresponsive to conventional treatment. It provides transitory hemodynamic support, oxygenation and removal of CO2, allowing pulmonary rest. Moreover it offers the possibility of ultraprotective ventilation and avoids generation of VILI (Ventilation-Induced Lung Injury). It is not frequently used in patients with hemodynamic failure secondary to obstructive shock due to mediastinal compromise. We present the case of a patient with obstructive shock, mediastinal mass of lymphoproliferative origin that was treated with extracorporeal arteriovenous circulation membrane.

La membrana de oxigenación extracorpórea arteriovenosa se utiliza cuando ocurre falla hemodinámica y respiratoria refractaria al tratamiento convencional; brinda soporte hemodinamico transitorio, oxigenacion y remocion de CO2, y permite reposo pulmonar. Asimismo ofrece la posibilidad de realizar ventilación ultraprotectiva y evitar la generación de VILI (Ventilation-Induced Lung Injury). No ha sido demostrada su utilización como una terapia frecuente en los casos con insuficiencia hemodinámica secundaria a shock obstructivo por afectación mediastínica. Presentamos el caso de un paciente con shock obstructivo por una masa mediastínica de origen linfoproliferativo tratada con membrana de circulación arteriovenosa extracorpórea.

Membrana de circulación extracorpórea en shock obstructivo secundario a enfermedad linfoproliferativa / Oxygenation with extracorporeal membrane in obstructive shock secondary to lymphoproliferative disease

La membrana de oxigenación extracorpórea arteriovenosa se utiliza cuando ocurre falla hemodinámica y respiratoria refractaria al tratamiento convencional; brinda soporte hemodinamico transitorio, oxigenacion y remocion de CO2, y permite reposo pulmonar. Asimismo ofrece la posibilidad de realizar ventilación ultraprotectiva y evitar la generación de VILI (Ventilation-Induced Lung Injury). No ha sido demostrada su utilización como una terapia frecuente en los casos con insuficiencia hemodinámica secundaria a shock obstructivo por afectación mediastínica. Presentamos el caso de un paciente con shock obstructivo por una masa mediastínica de origen linfoproliferativo tratada con membrana de circulación arteriovenosa extracorpórea.

The arteriovenous extracorporeal membrane is used in patients with hemodynamic and respiratory failure, unresponsive to conventional treatment. It provides transitory hemodynamic support, oxygenation and removal of CO2, allowing pulmonary rest. Moreover it offers the possibility of ultraprotective ventilation and avoids generation of VILI (Ventilation-Induced Lung Injury). It is not frequently used in patients with hemodynamic failure secondary to obstructive shock due to mediastinal compromise. We present the case of a patient with obstructive shock, mediastinal mass of lymphoproliferative origin that was treated with extracorporeal arteriovenous circulation membrane.