Efectos protectores de la hipotermia moderada en modelo de injuria pulmonar inducida por ventilación mecánica

Content Provider	Semantic Scholar
Author	Cruces, Pablo I. Ronco, Ricardo Erranz, Benjamín Conget, Paulette Pires, Yumai Carvajal, Cristóbal Colón De Donoso, Alejandro
Copyright Year	2007
Abstract	Se ha establecido que el empleo inapropiado de la ventilacion mecanica (VM) es capaz de generar dano pulmonar y de amplificar una noxa pulmonar pre-existente. Este fenomeno mecanico, denominado injuria pulmonar inducida por VM (VILI), es capaz de gatillar consecuencias biologicas locales y a distancia. La hipotermia ha sido empleada en situaciones clinicas que generan un desequilibrio entre la entrega y el consumo tisular de oxigeno, debido a su capacidad de reducir este ultimo. Nuestro objetivo fue determinar el efecto de la hipotermia moderada (HM) sobre marcadores biologicos de VILI e intercambio gaseoso.Se emplearon 12 ratas Sprague-Dawley machos adultas. Tras ser anestesiadas se intubaron y ventilaron mecanicamente en modalidad presion control, PIM 40 cmH2O, ZEEP, FR 60/min, TIM 25 por ciento, FIO2 100 por ciento. Los animales se aleatorizaron a grupos normotermia (N) (37 ± 1oC) y HM (34 ± 1oC), medido a nivel de esofago toracico. Se registro gasometria arterial, gravimetria, analisis histologico y medicion de concentracion de proteinas, interleukina (IL)-1[beta] (IL-1b) y factor de necrosis tumoral (TNF)-[alfa] (TNF-a) en el sobrenadante del lavado bronco alveolar (LBA) y plasma.Los animales con HM redujeron relacion peso humedo/seco y la PaCO2, respecto a los animales normotermicos, no siendo significativa la mejoria de la PaO2. Hubo ademas una reduccion de los niveles sistemicos de citoquinas inflamatorias en el grupo HM. No hubo diferencias respecto al score histologico de dano pulmonar ni de concentracion de proteinas en LBA. En este modelo experimental la HM provoco una reduccion del agua extravascular pulmonar y citoquinas inflamatorias plasmaticas, lo que refleja menor dano, asociado a una disminucion significativa en la PaCO2. Estos hechos ameritan la realizacion de nuevos estudios que demuestre su rol como terapia adyuvante al manejo ventilatorio de pulmones agudamente danados, ampliando el tradicional rol de la HM en cuidados criticos. The inadequate use of Mechanical Ventilation (MV) has proved to generate lung damage and to increase a pre-existing pulmonary injury. This mechanical event, called ventilator induced lung injury (VILI), can generate local and distant biological effects. Hypothermia has been used in clinical situations, which result in an imbalance between oxygen consumption (VO2) and delivery (DO2) due to its ability to reduce VO2. Our objective was to determine the effect of Moderate Hypothermia (MH) on biological markers of VILI and in gas exchange.Twelve Sprague-Dawley adult male rats were used. After anesthesia, the rats were randomly assigned to normothermia (37oC) and MH (34oC), which was induced by surface cooling. They were cannulated and mechanically ventilated with controlled pressure ventilation, PIP 40 cmH2O, ZEEP, (PEEP=0) RR 60/min, Ti 25 percent, FIO2 100 percent. The esophageal temperature was maintained within ± 1°C. Arterial blood gases, lung gravimetry, histological analysis and measurement of protein content, IL-1b and TNF-a were registered in the bronchoalveolar lavage (BAL) supernatant, both cytokines were also measured in plasma.The animals with MH showed a significant reduction in the wet lung weight/dry lung weight ratio and the PaCO2, in relation to the normothermic animals. There was also a reduction of the inflammatory systemic cytokines in the MH group. There were no differences in PaO2, histological score and protein content in BAL. In this experimental model, MH reduced extra vascular lung water, which reflects lesser damage associated to a significative reduction in PaCO2 and inflammatory systemic cytokines. These facts justify new studies, which would prove its role as an aid in the ventilatory management of severely damaged lungs, increasing the traditional role of MH in critical care.
Starting Page	15
Ending Page	21
Page Count	7
File Format	PDF HTM / HTML
Volume Number	22
Alternate Webpage(s)	http://www.medicina-intensiva.cl/revistaweb/revistas/2007/22-1-2007/full(12).pdf
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article