The Accuracy Of Bedside Ultrasonography In Emergency For Detecting Free Fluid In Patients With Severe Trauma And Its Feasibility In The Assessment Of Volume Status

Objective:To evaluate the accuracy of bedside ultrasonography(BUS)for detecting free fluid in body spaces of severe trauma patients(STPs)in the emergency department(ED)and its feasibility in the assessment of volume status.Methods:This was a prospective,observational,single-center study in the ED of The Second Hospital Affiliated to Soochow University between January 2017 and July 2017.STPs met the following criteria were enrolled in this study:?injury severity score(ISS)?16;?transported to our ED within 6 hours.The exclusion criteria were:?Dage<14 years;?BUS not suitable for STPs,including severe thoracic deformity,massive subcutaneous emphysema and unable to perform ultrasound examination of the lungs and heart;?STPs without Whole body computed tomography(WBCT)scan including the head,neck,chest,abdomen,pelvis;?STPs requiring tracheal intubation ventilator assisted breathing.The BUS was conducted by emergency physicians using the SONOSITE M-TURBO EQUIPMENT(Transducer C60x,5-2MHZ,Japan).(1)The first purpose of BUS was to identify free fluid,which necessarily means blood in acute trauma patients in body spaces,namely peritoneal,pericardial,pleural spaces and pneumothorax and pulmonary edema.Extended focused assessment with sonography(e-FAST)scan included views of subxiphoid,the right upper quadrant,the left upper quadrant,the suprapubic and the thoracic.We compelled the accuracy of e-FAST for detecting free fluid with WBCT.(2)We also performed BUS to assess the volume status of STPs.We measured the inferior vena cava(IVC)diameters by using the curved-array transducer(P21x,5-1 MHZ)in sagittal subxiphoid orientation.The IVC diameter was measured 2 cm below the cavoatrial junction.Inspiratory(IVCmin)and expiratory(IVCmax)diameters were obtained for comparison.The caval index was calculated as a percentage with the formula:IVCrvi=(IVCmax-IVCmin)/IVCmax.The left ventricular end-diastolic area(LVEDA)was measured by bedside echocardiography,LVEDA index(LVEDAI)=LVEDA/body surface area.We checked the feasibility of IVCrvi and LVEDAI in the assessment of volume status.Results:60 STPs were finally enrolled in this study.(1)By using CT as the reference standard,e-FAST showed a sensitivity of 74.1%and a specificity of 100%in detecting free fluid in body spaces.These results were consistent with WBCT and/or enhancement.(Kappa=0.759,P<0.001).(2)BUS showed that 12 of 60 patients had the IVC collapses during inspiration to more than 50%of its expiratory diameter.But collapsed IVC was not associated with shock index(SI),which was a sensitive index in the estimation of shock.Nevertheless,The LVEDAI was negatively associated with the circulatory volume status(r=-0.414,P<0.01).Conclusion:In our study,compared with WBCT,e-FAST has a good sensitivity and specificity for identification of free fluid in trauma patients.LVEDAI obtained from BUS showed a rapid method in the assessment of volume status.