Comparison of Lung Function Based on Electrical Impedance Tomography and CT Lung Volume in Patients With Rib Fractures

Rib fractures are one of the most common injuries following blunt trauma, occurring in approximately 10% of all trauma patients. Rib fracture injuries extend across a broad spectrum of severity from a single fractured rib which may be sustained in a fall or sporting injury, to multiple fractured ribs resulting in a flail chest with paradoxical chest wall movement and respiratory failure.

Flail chest, which defines multiple adjacent ribs broken in multiple places, is the most serious chest injury, and it damages the chest wall integrity and causes "paradoxical motion" from the detachment of a segment from the rest of the chest wall. Surgical management of rib fractures has received increasing attention in recent years with the development of new fixation techniques.

The mortality rate is 4% to 20%. Flail chest (FC), which defines multiple adjacent ribs broken in multiple places, is the most serious chest injury, and it damages the chest wall integrity and causes "paradoxical motion" from the detachment of a segment from the rest of the chest wall. Pulmonary contusion (PC) is the most common chest injury. These conditions frequently exist at the same time. Currently, a deeper understanding of FC pathophysiology exists, and its management has evolved substantially over the past 6 decades.

The earliest treatment for FC was surgery. With the increasing technological advancements available in the intensive care unit, conservative management, based on mechanical ventilation supplemented with intensive pain control, has become more common. Using positive airway pressure to reduce the asynchronous movement of FC could avoid surgical risks and postoperative complications. Conservative treatment has been administered frequently in previous years.

A growing number of researchers have found that surgery for FC could reduce the duration of mechanical ventilation, the ICU length of stay, the hospital length of stay, the incidence of pneumonia and tracheostomy, and mortality. Additional benefits included decreased doses of analgesic and sedative drugs and avoidance of thoracic deformity, and patients could return to previous employment quicker than could those treated conservatively.

Therefore, the improvement of lung function is a key indicator for the treatment of rib fractures and thoracic trauma, because lung function is related to lung expansion, chest wall stability, and thoracic deformation, which can lead to pneumonia, respiratory failure, difficult weaning, and prolong hospitalization. However, traditional pulmonary function measurement is based on an Incentive Spirometry. This examination requires the cooperation of the patient and also requires sufficient space and equipment. It is not suitable for acute trauma patients in intensive care units. In addition, the induced spirometer can only measure respiratory parameters such as vital capacity. It cannot locate and monitor the collapse part of lung and the range of pulmonary atelectasis. It must rely heavily on computer tomography and other imaging assistance, which is very unsatisfactory. Therefore, how to simultaneously develop an effective monitoring method for lung function and lung expansion is the current top priority.

For these reason, our research uses the electrical impedance tomography system (EIT), which can use the applied current and measurement voltage through the body surface electrode group, and use the reconstruction algorithm to construct an image imaging system that exceeds the cross-sectional, which can provide images of the internal physiological changes of the chest contour, in order to quantify the changes in lung function caused by rib fractures.

This study is a combine research project of patients from the Department of Traumatology of National Taiwan University Hospital and the Department of Traumatology of Far Eastern Memorial Hospital. The study is expected to be collected from July 2021 to December 2022 for one and a half years. Hospitalized patients with traumatic rib fractures were collected and analyzed in a prospective study method, and the patients with internal rib fractures in Far Eastern Memorial Hospital were collected and analyzed, and their lung function changes after the operation will be tracked.