Utility of Pulmonary Echography for Evaluation of Patients Undergoing Orthopedic Surgery for Femur Fracture

Overview

The stratification of perioperative risk is an essential moment in the preoperative evaluation of the patient undergoing surgery especially in the setting of urgency. There is a very broad group of indexes used in the stratification of preoperative risk, like ASA-PS (American Society of Anesthesiologists Physical Status), RCRI (Revised Cardiac Risk Index) and NSQIP MICA (National Surgical Quality Improvement Program Myocardial Infarction or Cardiac Arrest). The role of some laboratory markers such as BNP has also been demonstrated. The fundamental point of all these scores is cardiocirculatory compensation. There are concerns about the value of certain preoperative exams, especially in an urgent setting. Of them all, mostly chest X-ray is questioned. Chest X-ray, indeed, needs special costs, not always short execution times and the need for X-ray exposition. Furthermore, its utility is questionable in asymptomatic patients, in which there are often no alterations to be detected. Sensibility, for Thorax x-ray, is 41% for apical flow inversion, 27% for interstitial and 6% for alveolar oedema. In chronic decompensated patients, radiographic signs of congestion have a small diagnostic accuracy, being absent in 53% of patients with capillary pulmonary pressure between 16 and 29 mmHg and in 39% of those with wedge pressure more of 30 mmHg. Pulmonary echography is a known method, that has different possible applications in diagnosis of the lung parenchymal and pleural disease. Lung is made up for 80% of water. Extravascular lung water is physiologically less than 500 ml and it increases in the case of pathology. Augmentation of this water is detected reliably by echography. B-lines are an echographic artefact that allows recognition of interstitial syndrome, having a sensibility of 93,4% and specificity of 93%. Presence of 3 or more of B-lines in 2 out of 4 fields of each hemithorax can identify a cardiac problem like pulmonary sub-oedema or chronic heart failure and it is known as Diffuse Interstitial Syndrome. Thorax X-ray, instead, detects these situations only when extravascular water exceeds 30%. That's why echography has been proposed as a method for evaluation of extravascular pulmonary water. Moreover, when lung air component is lost enough in subpleural area, it is possible to find little consolidations. A method of reporting different grades of loss of aeration of the lung (normal pattern, isolated B lines, coalescent B lines and consolidation) has been proposed as a tool for monitoring the aeration itself. Pleural effusion is another sign that echography could detect. It is perfectly transonic and easy to see. Also, in this case, therefore, ultrasound is superior to X-ray, that has got sensibility, specificity and diagnostic accuracy of 67%, 70% and 67% respectively. All this information could provide useful elements for preoperative patient management. Echography, indeed, is a bedside and real-time method, that can give rapid information about the cardiocirculatory situation of patients. Using this method, that is non-invasive and easy, useful elements could be obtained, that could contribute to a better overview of clinical conditions of the patient in the preoperative setting. In the particular field of urgency and, among all, in the setting of orthopaedic urgency for femur fracture, there is a need for a more rapid and comprehensive evaluation, giving that the patient has to be operated within 24-48 hours. This timing is often incompatible with a long and time-consuming evaluation of the patients. Furthermore, a complete cardiologic examination is beyond the requirements of international guidelines for intermediate surgery, since it doesn't change the perioperative management. In this particular setting, hence, pulmonary echography could represent a more reliable and easier tool compared to thorax X-ray, often performed in non-optimal conditions (supine position, only anteroposterior chest X-ray). In recent studies, percentage of major adverse cardiovascular events (atrial fibrillation, flutter, acute heart failure and non-fatal acute myocardial infarction) after hip fracture has settled around 24.8%. This data confirms the importance of a valid preoperative stratification in this setting. From this perspective, this study aims to evaluate the utility of pulmonary echography as a preoperative method of investigation. The principal aim is to evaluate the utility of the pulmonary echography in predicting the risk of patients undergoing urgent surgery for femur fracture. Alternative objectives are: * Evaluate the predictability of LUS (lung ultrasound score) on the occurrence of MACE (major adverse cardiovascular events) * Verify feasibility of echographic evaluation in the estimation of fluid tolerance of patients undergoing orthopaedic surgery. * Evaluation of postoperative pulmonary complications (PPC)