Abstract 258: Dynamic Assessment of Lung Injury by Ultrasound in a Porcine Model of Cardiac Arrest Undergoing Therapeutic Hypothermia

Abstract

Introduction: Acute lung injury (ALI) is common in post-cardiac arrest syndrome (PCAS), which is associated with increased morbidity and mortality. Lung ultrasound, known as a noninvasive and easily-performed method, has a growing role in the assessment of lung injury. In this study, we investigated the effectiveness of lung ultrasound in monitoring ALI in a porcine model of cardiac arrest undergoing therapeutic hypothermia. Hypothesis: Lung ultrasound would be a promising approach to evaluate the severity of ALI in PCAS. Methods: Twenty-three male domestic swine weighing 36±3 kg were randomized into three groups: 1) therapeutic hypothermia (TH, n=9), 2) normothermia (NT, n=9), and 3) sham control (Control, n=5). Sham animals underwent the surgical preparation only. The animal model was established by 8 mins of ventricular fibrillation and then 5 mins of cardiopulmonary resuscitation. At 5 mins after resuscitation, therapeutic hypothermia was induced and maintained until 24 hrs post-resuscitation in the TH group. Body temperature was normally maintained in the other two groups. Lung ultrasound score (LUS), extra-vascular lung water index (ELWI), pulmonary vascular permeability index (PVPI) and PO 2 /FiO 2 were measured at baseline and at 1, 3, 6, 12, 24 hrs after resuscitation. Results: After resuscitation, LUS, ELWI and PVPI were significantly increased and PO 2 /FiO 2 was significantly decreased in the HT and NT groups than in the Control group. However, all of them were significantly better in the HT group compared to the NT group (Table). Additionally, increases in LUS were highly correlated with increases in ELWI ( r =0.613; p <0.001) and PVPI ( r =0.683; p <0.001), and decreases in PO 2 /FiO 2 ( r =-0.468; p <0.001). Conclusions: Lung ultrasound was a feasible approach to evaluate the severity of ALI in PCAS.