Diagnostic accuracy of focused assessment with ultrasonography for trauma (fast) performed by medical officers at Mulago hospital

Abstract

Introduction: Trauma remains the single most important cause of morbidity in the developing world and results in preventable loss of lives and years of productive life lost for the entire world population. Blunt abdominal trauma (BAT) accounts for 5% of all the mortality from trauma (Nadia Mama, 2012). Early diagnosis of concealed hemorrhage from BAT has remained a challenge in the emergency situation contributing to the high mortality and morbidity rates. Focused assessment with Sonography for Trauma (FAST) involves assessing a trauma patient at the bedside using ultrasound scan performed by trained emergency care providers (BFK, 1997). This technique saves time and is accurate in determining concealed hemorrhage in a timely manner compared to other modes of assessment. Its sensitivity has been shown to be more than 98% and with a specificity coming close to 100% (Ali Reza Ala, 2016 Sep) (Ollerton JE, 2006) (Soudack M, 2004). It has been widely adopted in the developed world for assessment of patients with tremendous results but has consistently eluded the practice in the developing world. Scale up has been limited by the number of trained specialists competent in this technique to evaluate trauma patients in the emergency departments (Rochelle A. Dicker, 2018). FAST has also shown to be equally accurate when it is applied by non-specialized doctors with similar accurate results in developed countries (Samjhana Basnet, 2020 Jul). In Uganda, Medical officers are responsible for the emergency evaluation and intervention for most of the trauma patients in the ER. (They are well trained in management of emergency patients and are the most available in most of the emergency departments in the developing world. Scaling FAST requires to skill the medical officers with this technique to aid evaluation and management of BAT in the ER. No studies in the resource limited setup have showed the accuracy of this technique when performed by non-specialized doctors in assessing concealed hemorrhage. This study assessed the effectiveness of this procedure when performed by medical officers who are non-specialists to identify fluid in the abdomen and chest and inform their management. OBJECTIVE: The aim of the study was to evaluate the diagnostic accuracy of FAST performed by medical officers for the diagnosis of hemorrhage in acute trauma patients in Mulago National Hospital. METHODS: This was a descriptive and analytical cross-sectional study, involving training medical officers based on the AUM curriculum by certified AUM trainers to carry out FAST, recruiting patients with trauma and assessing them using EFAST scans to evaluate for presence of concealed hemorrhage. The patients were then sent to the radiology department for evaluation using 2 comprehensive abdominal ultrasound scans to determine presence of free fluid (gold standard). The results of the FAST were compared with the radiologist’s findings in the radiology department. The diagnostic accuracy of the FAST was determined by evaluating the sensitivity, specificity, negative and positive predictive values of the test. Data analysis: The collected data was processed, analyzed and generally presented in form of tables, graphs and figures. Results In this study, five (5) medical officers were trained to conduct FAST, and enrolled 215 patients with suspected BAT. EFAST performed by MOs was able to identify 36 out of 39 positives and 175 of 176 negatives for hemoperitoneum and for the Chest, the EFAST was able identified 15 out of 17 positives and 197 of the 198 negatives for heamopneumothorax. The sensitivity Of EFAST was 92.3% for hemoperitonuim and 88.2% for hemopneumothorax. 99.4% Positive predictive value was found to be 97.3% and 99.5% for hemoperitoneum and hemopneumothorax respectively. The negative predictive value was 98.3% for hemoperitoneum and 93.8% for hemopneumothorax. Conclusion Medical officers can accurately assess trauma patients in the ED using the EFAST to determine presence of concealed heamorrhage or hemo-pneumothorax during initial evaluation of patients in the ED. Utility: This study provides evidence for the reliability of FAST scans performed by medical officers and will form a basis for the scale of the technique in the emergency departments within the country. Key Words: Diagnostic accuracy, FAST, concealed hemorrhage, and medical officers.