Page 20 - Ultrasonography in Prehospital and Emergency Medicine - Rein Ketelaars
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Chapter 1
There are also some disadvantages. The field of view may be limited, depending on both the transducer type and the presence of bone or air preventing further penetration of ultra- sound. The image quality may be reduced by body habitus or limited access caused by cloth- ing or defibrillator pads. Furthermore, the level of training and experience of the operator determines the success and quality of image acquisition, the interpretation of the images and thus the diagnostic performance of ultrasonography.
A short history of ultrasonography
Medical ultrasonography made its appearance shortly after the second world war. It was first described by Karl Theo Dussik in 1942 and he published the first ultrasound images in 1947.3,4 At that time, the technology consisted of huge machines that produced low-quality imag- es. Although ultrasound devices became increasingly portable, it took over 35 years before the first report on prehospital ultrasonography (PHUS) was published in 1983.5 The authors described the successful use of a portable ultrasound device in prehospital patients by the French emergency medical services; Service d’Aide Médicale Urgente (SAMU).
To put this into perspective, both the pulse oximeter and the colorimetric CO2-detector were introduced in the prehospital setting around 1988.6,7 And the prehospital use of porta- ble quantitative waveform capnography was first reported in 1994.8
Before then, the assessment of prehospital patients relied on history-taking, physical ex- amination, blood pressure measurements and electrocardiography. A physical examination traditionally consists of observation, auscultation, percussion, and palpation. Similarly, the Advanced Trauma Life Support (ATLS) course dictates to look, listen, and feel to conduct an initial assessment in trauma patients.9 A noisy emergency department or—even worse—the noisy prehospital environment poses a serious challenge to those who attempt to reliably evaluate injured or critically ill patients. This challenge is aggravated by the ever-present time pressure, limited working space, excessive heat or cold, and other environmental fac- tors.
Through physical examination alone, it is hard to diagnose a (simple) pneumothorax. During the primary evaluation of trauma patients, auscultation of the chest (using a stethoscope) has a sensitivity to detect a hemothorax, hemopneumothorax, or pneumothorax of only 58%.10 Others reported that auscultation for (hemo)pneumothorax has a sensitivity of 59–66%.11,12 Besides (hemo)pneumothorax, the detection of intraperitoneal free fluid, pericardial effu- sion or tamponade, or endobronchial (as opposed to endotracheal) intubation may be as hard, or even harder!13

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