Rasmus Aagaard

A framework for implementation, education, research and clinical use of ultrasound in emergency departments by the Danish Society for Emergency Medicine

The first Danish Society for Emergency Medicine (DASEM) recommendations for the use of clinical ultrasound in emergency departments has been made. The recommendations describes what DASEM believes as being current best practice for training, certification, maintenance of acquired competencies, quality assurance, collaboration and research in the field of clinical US used in an ED.

Animal Laboratory Training Improves Lung Ultrasound Proficiency and Speed

BACKGROUND Although lung ultrasound (US) is accurate in diagnosing pneumothorax (PTX), the training requirements and methods necessary to perform US examinations must be defined. OBJECTIVE Our aim was to test whether animal laboratory training (ALT) improves the diagnostic competency and speed of PTX detection with US. METHODS Twenty medical students without lung US experience attended a 1-day course. Didactic, practical, and experimental lectures covered the basics of US physics, US machines, and lung US, followed by hands-on training to demonstrate the signs of normal lung sliding and PTX. Each students diagnostic skill level was tested with three subsequent examinations (at day 1, day 2, and 6-month follow-up) using experimentally induced PTX in porcine models. The outcome measures were sensitivity and specificity for US detection of PTX, self-reported diagnostic confidence, and scan time. RESULTS The students improved their skills between the initial two examinations: sensitivity increased from 81.7% (range 69.1%-90.1%) to 100.0% (range 94.3%-100.0%) and specificity increased from 90.0% (range 82.0%-94.8%) to 98.9% (range 92.3%-100.0%); with no deterioration 6 months later. There was a significant learning curve in choosing the correct answers (p = 0.018), a 1-point increase in the self-reported diagnostic confidence (7.8-8.8 on a 10-point scale; p < 0.05), and a 1-min reduction in the mean scan time per lung (p < 0.05). CONCLUSIONS Without previous experience and after undergoing training in an animal laboratory, medical students improved their diagnostic proficiency and speed for PTX detection with US. Lung US is a basic technique that can be used by novices to accurately diagnose PTX.

Developing an emergency ultrasound app - a collaborative project between clinicians from different universities

Focused emergency ultrasound is rapidly evolving as a clinical skill for bedside examination by physicians at all levels of education. Ultrasound is highly operator-dependent and relevant training is essential to ensure appropriate use. When supplementing hands-on focused ultrasound courses, e-learning can increase the learning effect. We developed an emergency ultrasound app to enable onsite e-learning for trainees. In this paper, we share our experiences in the development of this app and present the final product.

Microdialysis: characterisation of haematomas in myocutaneous flaps by use of biochemical agents

Metabolic markers are measured by microdialysis to detect postoperative ischaemia after reconstructive surgery with myocutaneous flaps. If a haematoma develops around the microdialysis catheter, it can result in misinterpretation of the measurements. The aim of the present study was to investigate whether a haematoma in a flap can be identified and dissociated from ischaemia, or a well-perfused flap, by a characteristic chemical profile. In 7 pigs, the pedicled rectus abdominal muscle flap was mobilised on both sides. A haematoma was made in each flap and two microdialysis catheters were placed, one in the haematoma, and the other in normal tissue. One flap was made ischaemic by ligation of the pedicle. For 6 hours, the metabolism was monitored by measurement every half-an-hour of the concentrations of glucose, lactate, pyruvate, and glycerol from all 4 catheters. After 3 hours of monitoring, intravenous glucose was given as a challenge test to identify ischaemia. The non-ischaemic flap could be differentiated from the ischaemic flap by low glucose, and high lactate, concentrations. It was possible to identify a catheter surrounded by a haematoma in ischaemic as well as non-ischaemic muscle from a low or decreasing concentration of glucose together with a low concentration of lactate. All four sites could be completely dissociated when the concentrations of glucose and lactate were evaluated and combined with the lactate:glucose ratio and a flow chart. The challenge test was useful for differentiating between haematomas in ischaemic and non-ischaemic tissue.

The intrapleural volume threshold for ultrasound detection of pneumothoraxes

Objectives Small pneumothoraxes (PTXs) may not impart an immediate threat to trauma patients after chest injuries. However, if these patients require positive pressure ventilation even a small amount of pleural air may be relevant. Point-of-care lung ultrasonography (US) is a reliable tool in the diagnosis of PTX, but the performance characteristics regarding detection of miniscule PTXs needs to be defined. We aimed at finding the volume threshold of intrapleural air where PTXs confidently can be diagnosed.

A low end-tidal CO2/arterial CO2 ratio during cardiopulmonary resuscitation suggests pulmonary embolism

INTRODUCTION Identifying reversible causes of cardiac arrest is challenging. The diagnosis of pulmonary embolism is often missed. Pulmonary embolism increases alveolar dead space resulting in low end-tidal CO2 (EtCO2) relative to arterial CO2 (PaCO2) tension. Thus, a low EtCO2/PaCO2 ratio during resuscitation may be a sign of pulmonary embolism. METHODS Post hoc analysis of data from two porcine studies comparing ultrasonographic measurements of right ventricular diameter during resuscitation from cardiac arrest of different causes. Pigs were grouped according to cause of arrest (pulmonary embolism, hypovolemia, primary arrhythmia, hypoxia, or hyperkalaemia) and EtCO2/PaCO2 ratios were compared. RESULTS Data from 54 pigs were analysed. EtCO2 levels at the third rhythm analysis were significantly lower when cardiac arrest was caused by pulmonary embolism than by primary arrhythmia, hypoxia and hyperkalaemia, but there was no significant difference between pulmonary embolism and hypovolemia. In contrast, PaCO2 levels were higher in cardiac arrest caused by pulmonary embolism than in the other causes of cardiac arrest. Consequently, the EtCO2/PaCO2 ratio was lower in pulmonary embolism 0.2 (95%CI 0.1-0.4), than in hypovolaemia 0.5 (95%CI 0.3-0.6), primary arrhythmia 0.7 (95%CI 0.7-0.8), hypoxia 0.5 (95%CI 0.4-0.6), and hyperkalaemia 0.6 (95%CI 0.6-0.7). CONCLUSION A low EtCO2/PaCO2 ratio during cardiopulmonary resuscitation suggests pulmonary embolism.

Remote real‐time supervision via tele‐ultrasound in focused cardiac ultrasound: A single‐blinded cluster randomized controlled trial

Supervision via tele‐ultrasound presents a remedy for lacking on‐site supervision in focused cardiac ultrasound, but knowledge of its impact is largely absent. We aimed to investigate tele‐supervised physicians’ cine‐loop quality compared to that of non‐supervised physicians and compared to that of experts.

Clinical experience and skills of physicians in hospital cardiac arrest teams in Denmark: a nationwide study

Background The quality of in-hospital resuscitation is poor and may be affected by the clinical experience and cardiopulmonary resuscitation (CPR) training. This study aimed to investigate the clinical experience, self-perceived skills, CPR training and knowledge of the guidelines on when to abandon resuscitation among physicians of cardiac arrest teams. Methods We performed a nationwide cross-sectional study in Denmark. Telephone interviews were conducted with physicians in the cardiac arrest teams in public somatic hospitals using a structured questionnaire. Results In total, 93 physicians (53% male) from 45 hospitals participated in the study. Median age was 34 (interquartile range: 30–39) years. Respondents were medical students working as locum physicians (5%), physicians in training (79%) and consultants (16%), and the median postgraduate clinical experience was 48 (19–87) months. Most respondents (92%) felt confident in treating a cardiac arrest, while fewer respondents felt confident in performing intubation (41%) and focused cardiac ultrasound (39%) during cardiac arrest. Median time since last CPR training was 4 (2–10) months, and 48% had attended a European Resuscitation Council (ERC) Advanced Life Support course. The majority (84%) felt confident in terminating resuscitation; however, only 9% were able to state the ERC guidelines on when to abandon resuscitation. Conclusion Physicians of Danish cardiac arrest teams are often inexperienced and do not feel competent performing important clinical skills during resuscitation. Less than half have attended an ERC Advanced Life Support course, and only very few physicians know the ERC guidelines on when to abandon resuscitation.