Disfunción primaria del injerto tras el trasplante pulmonar / Primary graft dysfunction after lung transplantation

El trasplante pulmonar representa una opción terapéutica para procesos pulmonares en los que los tratamientos han fallado o que presenten una evolución rápidamente progresiva. Sin embargo, no está libre de complicaciones, siendo la disfunción primaria del injerto una de ellas. Se trata de una forma de lesión pulmonar aguda, y caracterizada por desarrollarse durante el postoperatorio inmediato, estar asociada a una alta morbi-mortalidad y aumentar el riesgo de bronquiolitis obliterante. Ha presentado diferentes acepciones terminológicas conduciendo a un documento de consenso que precisara su definición en el año 2005. En ese consenso se acordó considerar la disfunción primaria del injerto como edema pulmonar no cardiogénico en las primeras 72 horas de la reperfusión y debido a una alteración del propio parénquima pulmonar. Se han llevado a cabo estudios que tratan de identificar factores de riesgo y de conocer la fisiopatología subyacente para secundariamente desarrollar posibles opciones terapéuticas. Entre las opciones de tratamiento se encuentran el óxido nítrico o el surfactante pulmonar junto con las medidas de soporte como ventilación mecánica o la oxigenación extracórporea (AU)

Lung transplantation is a therapeutic option for pulmonary diseases in which the other treatment options have failed or in cases of rapid disease progression. However, transplantation is not free from complications, and primary graft dysfunction is one of them. Primary graft dysfunction is a form of acute lung injury. It characteristically develops during the immediate postoperative period, being associated to high morbidity and mortality, and increased risk of bronchiolitis obliterans. Different terms have been used in reference to primary graft dysfunction, leading to a consensus document to clarify the definition in 2005. This consensus document regards primary graft dysfunction as non-cardiogenic pulmonary edema developing within 72hours of reperfusion and intrinsically attributable to alteration of the lung parenchyma. A number of studies have attempted to identify risk factors and to establish the underlying physiopathology, with a view to developing potential therapeutic options. Such options include nitric oxide and pulmonary surfactant together with supportive measures such as mechanical ventilation or oxygenation bypass (AU)

[Primary graft dysfunction after lung transplantation]. / Disfunción primaria del injerto tras el trasplante pulmonar.

Lung transplantation is a therapeutic option for pulmonary diseases in which the other treatment options have failed or in cases of rapid disease progression. However, transplantation is not free from complications, and primary graft dysfunction is one of them. Primary graft dysfunction is a form of acute lung injury. It characteristically develops during the immediate postoperative period, being associated to high morbidity and mortality, and increased risk of bronchiolitis obliterans. Different terms have been used in reference to primary graft dysfunction, leading to a consensus document to clarify the definition in 2005. This consensus document regards primary graft dysfunction as non-cardiogenic pulmonary edema developing within 72 hours of reperfusion and intrinsically attributable to alteration of the lung parenchyma. A number of studies have attempted to identify risk factors and to establish the underlying physiopathology, with a view to developing potential therapeutic options. Such options include nitric oxide and pulmonary surfactant together with supportive measures such as mechanical ventilation or oxygenation bypass.

Valor de la fracción de espacio muerto (Vd/Vt) como predictor de éxito en la extubación / Utility of the dead space fraction (Vd/Vt) as a predictor of extubation success

Objetivo: Comprobar qué valor tiene la fracción de espacio muerto (Vd/Vt) como predictor del fracaso en la extubación de los enfermos que necesitaron ventilación mecánica (VM) ingresados en las unidades de cuidados intensivos. Diseño: Estudio de cohortes, prospectivo, observacional. Desde el 1 de septiembre de 2010hasta 1 de marzo de 2011.Ámbito: Unidad de cuidados intensivos generales (UCIG), del complejo hospitalario de tercer nivel Hospital Universitario Marqués de Valdecilla. Pacientes o participantes: Se han incluido en el estudio aquellos enfermos que recibían VM por un espacio de tiempo superior a las 12 horas; y quienes en el proceso de destete seguían un protocolo de presión soporte de bajo nivel. Han sido criterios de exclusión la edad inferior a 18anos, enfermos ventilados a través de traqueotomía y enfermos considerados no colaboradores ˜por diversas causas. Durante el periodo de estudio, ingresaron en UCIG 392 enfermos. De ellos 214 precisaron ventilación mecánica. En 154 se inició proceso de destete. Fueron excluidos del estudio 54 enfermos y no fueron extubados de VM 24. Finalmente 76 enfermos fueron extubados y analizados. Variables de interés principales: Se calculó Vd/Vt como el cociente (PaCO2-PC CO2)/PaCO2;con los parámetros registrados. Resultados: El análisis de regresión logística mostró una asociación significativa entre la variable Vd/Vt y el fracaso en la extubación con una OR de 1,52 (IC 95%: 1,11-2,09; p = 0,008). El área bajo la curva ROC, con respecto a predecir el fracaso en la extubación mediante el valor deVd/Vt fue de 0,94 (IC 95%: 0,86-0,98; p < 0,0001) (AU)

Purpose: To determine the value of Vd/Vt as a predictor of extubation failure in patients with mechanical ventilation admitted to the intensive care units. Design: A prospective, observational cohort study conducted from 1 September 2010 to 1 March2011.Setting: General intensive care unit (G-ICU) of a third level university hospital. Patients or participants: The study included patients on mechanical ventilation (MV) for over12 hours, and who in the process of weaning were subjected to low-level pressure support. Exclusion criteria were age under 18 years, ventilation via tracheotomy and patients failing to cooperate for different reasons. During the study, 392 patients were admitted to the G-ICU; of these, 214 required MV. The weaning process was started in 154 cases. Fifty-four patients were excluded from the study, and 24 were not extubated from MV. A total of 76 patients were finally extubated and analyzed. Variables of interest: Vd/Vt was calculated as the ratio (PaCO2-PC CO2)/PaCO2, with the recorded parameters. Results: Logistic regression analysis showed a significant association between the Vd/Vt and extubation failure, with OR = 1.52 (95%CI 1.11 to 2.09, p = 0.008).The area under the ROC curve with respect to the prediction of extubation failure according to the Vd/Vt value was 0.94 (95%CI 0.86 to 0.98, p < 0.0001) (AU)

[Utility of the dead space fraction (Vd/Vt) as a predictor of extubation success]. / Valor de la fracción de espacio muerto (Vd/Vt) como predictor de éxito en la extubación.

PURPOSE: To determine the value of Vd/Vt as a predictor of extubation failure in patients with mechanical ventilation admitted to the intensive care units. DESIGN: A prospective, observational cohort study conducted from 1 September 2010 to 1 March 2011. SETTING: General intensive care unit (G-ICU) of a third level university hospital. PATIENTS OR PARTICIPANTS: The study included patients on mechanical ventilation (MV) for over 12 hours, and who in the process of weaning were subjected to low-level pressure support. Exclusion criteria were age under 18 years, ventilation via tracheotomy and patients failing to cooperate for different reasons. During the study, 392 patients were admitted to the G-ICU; of these, 214 required MV. The weaning process was started in 154 cases. Fifty-four patients were excluded from the study, and 24 were not extubated from MV. A total of 76 patients were finally extubated and analyzed. VARIABLES OF INTEREST: Vd/Vt was calculated as the ratio (PaCO(2)-Pє CO(2))/PaCO(2), with the recorded parameters. RESULTS: Logistic regression analysis showed a significant association between the Vd/Vt and extubation failure, with OR=1.52 (95%CI 1.11 to 2.09, p=0.008). The area under the ROC curve with respect to the prediction of extubation failure according to the Vd/Vt value was 0.94 (95%CI 0.86 to 0.98, p<0.0001). CONCLUSIONS: Vd/Vt is a powerful predictor of extubation failure in patients on MV.