Sensitivity of ultrasound for the evaluation of trauma. Experience in Cuba

Sensibilidad de la ecografía para la evaluación del trauma. Experiencia en Cuba

Alain David Medina-Lago

Medical University of Havana, Cuba

Oscar Díaz-Pi

Medical University of Havana, Cuba

Isabela Bezerra Ferreira da Silva

Medical University of Havana, Cuba

Yoján Garrido-León

Medical University of Havana, Cuba

Trauma is one of the most important medical conditions in modern life. It claims millions of lives and results in enormous economic burdens. It is regarded as the ongoing pandemic of our time ¹ and is the main cause of death in Cuba for people under 45 years of age ².

Ultrasound has been used as diagnostic tool for more than 60 years, for example, gynaecologists to differentiate abdominal masses ³. It has also been promoted in the United States as a tool for surgeons by the American College of Surgeons, which create a training program for surgeons in the use of ultrasound ^4-7.

Bedside ultrasound has become the preferred initial imaging method for trauma care and is incorporated into the Advanced Trauma Life Support guidelines created by the American College of Surgeons ^8-12.

Scientific evidence has shown that ultrasound is more sensitive (49-99%) than traditional chest X-rays (27-75%) in detecting hemothorax and pneumothorax. It is important to note that chest radiography has been shown to miss 30-50% of pneumothoraces ^8,9,13.

This study aimed to determine the sensitivity and specificity of Extended Focused Assessment with Sonography for Trauma (E-FAST), when conducted by general surgeons.

This observational, cross-sectional, prospective study was conducted at the Hospital Universitario Miguel Enríquez to determine the sensitivity and specificity of E-FAST, as performed by general surgeons. The population consisted of patients admitted to the emergency department of the Miguel Enríquez University Hospital with a history or suspicion of sustained a traumatic injury, whether penetrating or not, for whom a trained general surgeon performed E-FAST ultrasound during the initial evaluation.

Statistical analysis

Computed tomography (CT), the gold standard test in trauma assessment, was performed for cases that were hemodynamically stability. For those who were not hemodynamically stable and who required immediate surgery, E-FAST analysis was compared with intraoperative findings. The results of these tests were converted into dichotomous variables with values of positive and negative. The data obtained were processed using SPSS software and were plotted in appropriate frequency distribution tables, 2 x 2 tables, and ROC (Receiver Operating Characteristics) curves. The information was analysed and compared with the results obtained by national and international authors.

General characteristics of the patients studied

One hundred and ten patients were examined after experiencing acute traumatic injuries and being admitted to the emergency department; 72.7% were male (n=80), and 27.3% were female (n=30). The median age was 38 years. The E-FAST analysis allowed a quick assessment to be performed in the trauma room, while initial trauma resuscitation maneuvers were being performed. The predominant ultrasound finding was the absence of pleural sliding in both hemithoraxes, and presence of free fluid in the cul-de-sac (Table 1).

Table 1.
General characteristics of the patients.

Comparison of E-FAST with gold standard tests

The entire sample of 110 patients was assessed for trauma using E-FAST. Of these, 65 patients were hemodynamically stable, which allowed them undergo CT. The CT results coincided with those of the ultrasound results in 62 cases. The E-FAST analysis showed 17 patients who presented criteria interpreted as a positive test; two of these cases were not confirmed by CT. The E-FAST analysis found 48 negative cases; in one of these cases, the CT examination found a left traumatic pneumothorax with small volume of 15%, which was treated conservatively.

In the remaining 45 patients, whose hemodynamic status necessitated emergency surgery, E-FAST analysis matched the intraoperative findings in 44 cases. One patient was found to have 300 ml of free blood in the cavity, as well as a pelvic fracture with large hematoma in the preperitoneal area. The details of these tests are shown in Table 2.

Table 2.
Comparison of E-FAST with gold standard tests.

In the study, the diagnostic accuracy for E-FAST was 0.964 (0.909 - 0.990), with a sensitivity in the detection of free fluid and pneumothorax of 96.4% (87.8 - 99.5%) and a specificity of 96.2% (87 - 99.5%); the confidence interval (CI) for these measures was 95%. The diagnostic utility of the E-FAST exam components is shown in Table 3 and Figure 1.

Table 3.
Diagnostic utility of the E-FAST exam compared with the gold standard.

Figure 1.
ROC curve corresponding to E-FAST. Calculation of the sensitivity and specificity tests with an area under the curve of 0.964 (0.923 - 100) for a 95% confidence interval.

This is the first study in Cuba to evaluate the diagnostic accuracy of the E-FAST test in trauma patients. This research indicates that E-FAST evaluations are a useful tool in the detection of intra-abdominal free fluid, traumatic hemothorax, and traumatic pneumothorax, given their high sensitivity, specificity, and positive and negative predictive values. When compared these results with studies published in the literature from different institutions worldwide, a range of sensitivity (67-99%), specificity (89-99%), and diagnostic precision (85-100%) is found for the usefulness of the E-FAST examination ^14-19. A recent systematic review by Netherton et al. ²⁰ evaluated 75 studies to determine the diagnostic values of the E-FAST test, which showed ranges of values for sensitivity (40 - 100%) and specificity (94 - 100%). In a recent study reported by Basnet et al. ²¹ in 261 patients with trauma, they determined a sensitivity of 94.8%, specificity of 99.5%, negative predictive value of 98.5%, positive predictive value of 98.2, and diagnostic accuracy of 98.4 for the E-FAST examination compared with chest X-ray, chest and abdominal CT and exploratory laparotomy. This last study had similar results as ours. Among the patients in the study, most were male (72.7%), aligning with another study that found 74% of patients were male. This gender disparity is further highlighted by the higher rate of disability-adjusted life years from transport injuries in men compared to women ²².

This research shows that the E-FAST test performed by a general surgeon presents diagnostic values that make it a reliable and fast tool to evaluate trauma patients. It is a feasible method with high sensitivity, specificity, and positive and negative predictive values. The E-FAST test is particularly beneficial in the early assessment of trauma patients to determine the necessity for immediate surgery.