A Framework for Case-Based Learning in Prehospital Medicine: The London's Air Ambulance Experience.

Clinical governance is the framework around which health care organizations can maintain a higher standard of safety and care. One of the central aspects of clinical governance is continuous professional education, including case-based review and case-based learning. In this article, we present the case-based education process in use at London's Air Ambulance, a mature advanced prehospital system in London, UK. The case review process begins with an on-scene hot debrief, an informal process often involving other emergency services. This is usually followed by internal team feedback and debrief and patient follow-up. All cases are then reviewed over the next 24 to 48 hours by the duty prehospital consultant (attending) in the rapid review process. After this, certain cases are volunteered or selected for discussion in the twice weekly death and disability (D&D) meeting or the monthly dispatch meeting. A small subset of cases is highlighted through this process for full formal audit and presentation at the monthly clinical governance meetings based on their educational value. Another subset of cases involving a fatality is also discussed at the monthly clinical pathology correlation meeting with the input of local forensic pathologists. Organization of the process, structure of the meetings, and educational value are described in detail.

Low complexity lossless compression of underwater sound recordings.

Autonomous listening devices are increasingly used to study vocal aquatic animals, and there is a constant need to record longer or with greater bandwidth, requiring efficient use of memory and battery power. Real-time compression of sound has the potential to extend recording durations and bandwidths at the expense of increased processing operations and therefore power consumption. Whereas lossy methods such as MP3 introduce undesirable artifacts, lossless compression algorithms (e.g., flac) guarantee exact data recovery. But these algorithms are relatively complex due to the wide variety of signals they are designed to compress. A simpler lossless algorithm is shown here to provide compression factors of three or more for underwater sound recordings over a range of noise environments. The compressor was evaluated using samples from drifting and animal-borne sound recorders with sampling rates of 16-240 kHz. It achieves >87% of the compression of more-complex methods but requires about 1/10 of the processing operations resulting in less than 1 mW power consumption at a sampling rate of 192 kHz on a low-power microprocessor. The potential to triple recording duration with a minor increase in power consumption and no loss in sound quality may be especially valuable for battery-limited tags and robotic vehicles.

Improving outcome in severe trauma: trauma systems and initial management: intubation, ventilation and resuscitation.

Severe trauma is an increasing global problem mainly affecting fit and healthy younger adults. Improvements in the entire pathway of trauma care have led to improvements in outcome. Development of a regional trauma system based around a trauma centre is associated with a 15-50% reduction in mortality. Trauma teams led by senior doctors provide better care. Although intuitively advantageous, the involvement of doctors in the pre-hospital care of trauma patients currently lacks clear evidence of benefit. Poor airway management is consistently identified as a cause of avoidable morbidity and mortality. Rapid sequence induction/intubation is frequently indicated but the ideal drugs have yet to be identified. The benefits of cricoid pressure are not clear cut. Dogmas in the management of pneumothoraces have been challenged: chest x-ray has a role in the diagnosis of tension pneumothoraces, needle aspiration may be ineffective, and small pneumothoraces can be managed conservatively. Identification of significant haemorrhage can be difficult and specific early resuscitation goals are not easily definable. A hypotensive approach may limit further bleeding but could worsen significant brain injury. The ideal initial resuscitation fluid remains controversial. In appropriately selected patients early aggressive blood product resuscitation is beneficial. Hypothermia can exacerbate bleeding and the benefit in traumatic brain injury is not adequately studied for firm recommendations.

Improving outcome in severe trauma: what's new in ABC? Imaging, bleeding and brain injury.

Appropriate imaging is critical in the initial assessment of patients with severe trauma. Plain radiographs remain integral to the primary survey. Focused ultrasonography is useful for identifying intraperitoneal fluid likely to represent haemorrhage in patients who are shocked and also has a role in identifying intrathoracic pathology. Modern scanners permit a greater role for CT, being more rapid and exposing the patient to less ionising radiation. 'Whole body' (head to pelvis) CT scanning has been shown to identify injuries missed by 'traditional' focused assessment and may be associated with an improved outcome. CT identifies more spinal injuries than plain radiographs, is the gold standard for diagnosing blunt aortic injury and facilitates non-operative management of solid organ injury and other bleeding. Coagulopathy occurs early in trauma as a direct result of injury and hypoperfusion. Damage control resuscitation with blood components is associated with an improved outcome in patients with trauma with massive haemorrhage. Packed cells and fresh frozen plasma should be used in a 1:1 to 1:2 ratio. Bedside measures of coagulopathy may prove useful. Adjuvant early treatment with tranexamic acid is of benefit in reducing blood loss and reducing mortality. Limited 'damage control surgery' with early optimisation of physiology augmented by interventional radiology to control haemorrhage is preferable to early definitive care. Limiting haemorrhage by correction of anticoagulation and minimising secondary brain injury through optimal supportive care is critical to improving outcome in neurotrauma.

Toll-like receptor 4 variants reduce airway response in human subjects at high endotoxin levels in a swine facility.

BACKGROUND: Toll-like receptor 4 (TLR4) variants have been shown to reduce the respiratory responses to inhaled LPS in controlled experiments among healthy volunteers. OBJECTIVE: We sought to investigate whether naive subjects with TLR4 variants showed reduced respiratory response to a complex aerosol including endotoxin as a major constituent. METHODS: Twenty-nine nonsmoking, nonatopic healthy subjects with TLR4 299/399 polymorphisms and 29 age- and sex-matched, wild-type TLR4 control subjects were exposed for 5 hours each in a noncontaminated environment (baseline day) and in a swine confinement facility (exposure day). There were 16 men and 13 women in each of the 2 age- and sex-matched groups. RESULTS: TLR4 polymorphic subjects who were exposed to high endotoxin levels (>or=1550 EU/m(3)) had less reduction in the percentage across-shift change in FEV(1) from baseline than did wild-type subjects exposed to similar endotoxin levels. Among subjects exposed to higher endotoxin levels, the mean differences in the percentage across-shift changes between baseline and exposure days were significantly less in TLR4 polymorphic subjects compared with those seen in wild-type subjects in FEV(1) (-8.48% +/- 1.52% [mean +/- SE] vs -11.46% +/- 1.79%, P = .001), forced expiratory flow between 25% and 75% of forced vital capacity (-18.30% +/- 1.99% vs -24.14% +/- 3.28%, P = .009), and FEV(1)/forced vital capacity ratio (-5.40% +/- 0.56% vs -8.53% +/- 1.51%, P = .04). These patterns were not observed in IL-6 levels from serum and nasal lavage fluid, IL-8 levels from nasal lavage fluid, white blood cell counts, or blood differential counts. CONCLUSION: The association between TLR4 variants and reduced airway responsiveness to inhaled particulate was observed at high endotoxin concentrations, creating the possibility of certain threshold phenomena for the apparent protective effect of TLR4 variants.