New content quiz December 2105

The most appropriate US probe to use for echocardiography is a phased array probe. Linear probes are used mostly for vascular access and soft tissue studies and the curvilinear probe for abdominal and thoracic US. (link)

The main benefit of a vertical mattress suture in wound repair is to reduce the dead space in a wound. Horizontal mattress sutures help spread tension across a long wound and neither have a direct effect on wound infection or the end cosmetic effect of suture marks (although a wound with good deep tissue apposition may have a better cosmetic result and may be a bit less prone to infection). (link)

The part of the suture needle that joins with the suture material is the swage.(link)

The risk of Hepatitis B transmission following a percutaneous needle stick injury from a source that is e antigen positive is approximately 40%. The risk is only approximately 5% if the source is e antigen negative (link)

The approximate size and location of an Implanon contraceptive is a 4 cm X 2 mm rod inserted under the skin of the inner arm above the elbow. (link)

An advantage of taping an ETT in place instead of tying it is usually quicker to remove. Taping is usually not as effective at securing an ETT in patients with facial hair or wet skin. Taping does not obstruct cerebral venous return, which is another advantage. (link)

When draining a large spontaneous pneumothorax with almost complete collapse of the lung in a thin patient, the most common potential adverse effect is pain on re-expansion. Malposition should be very uncommon with the lung fully collapsed, as is infection and haemothorax in primary pneumothoraces.(link)

A Heimlich valve is a portable one way valve system suitable for transport or outpatient treatment of pneumothorax. Gas passes from the ICC through a fine rubber sleeve and exits the end, closing on inspiration to prevent gas from passing back into the chest. The sleeve expands on expiration (becomes wider) and collapses on inspiration when ICC correctly placed. It does not require water levels to maintain a seal, so it more convenient than UWSDs for transport. Drainage of pleural fluid or clots may prevent valve operation so is usually only suitable for drainage of pneumothoraces.(link)

The preferred method for securing an ICC is to wind the lazy ends of the suture around the base of the ICC in opposite directions then tie them together to secure the tube. Placing a horizontal mattress suture around ICC is an alternative. Avoid using a “purse string” suture as this is painful and may cause scarring and do not use a Roman sandal technique of winding the lazy end of the suture in a weave pattern up the ICC as this allows too much in an out movement of the ICC. Securing an ICC with tape alone is insufficiently secure (link)

Management of a sucking chest wound involves immediately sealing the wound with occlusive dressing to reduce the ingress of air on inspiration. A 3 sided occlusive dressing can be applied (with free edge downwards to allow egress of blood) to act as a one way valve or a SAM® chest seal dressing with included expiration valve can also be used. If dressings are unsuccessful roughly close the wound with sutures and use positive pressure ventilation, if ventilation is still poor despite all attempts to close the defect. Decompression of the pneumothorax (through a different site) should occur as soon as possible. (link)

Indications in patients > 16 years of age are: unexplained seizure; chronic headache with suspected intracranial pathology; cervical radiculopathy; cervical trauma; acute anterior cruciate ligament or meniscal tears. GPs can currently (Dec 2015) only order MRI for elbow injuries and suspected scaphoid injuries in patients < 16 years of age. (link)

STIR suppresses the high signal intensity (white) of fat and is good for imaging fractures. FLAIR
is useful for the detection of subtle changes at the periphery of the hemispheres and in the periventricular region close to CSF especially in: stroke; MS; SAH; traumatic cerebral infarction. TIRM is used for the assessment of osteomyelitis and head and neck tumours. DIR
suppresses signal from the CSF and white matter to enhance the appearance of inflammatory lesions and is used in: MS and detection of infratentorial or spinal cord lesions. Diffusion weighted sequences (DWI) is used in: early identification of ischaemic stroke; differentiation of epidermoid cyst from arachnoid cyst; differentiation of abscess from necrotic tumours; differentiation of herpes encephalitis from diffuse temporal gliomas; assessment of the extent of diffuse axonal injury; assessment of active demyelination. (link)

The #11 blade has a triangular pointed tip making it ideal for stab incisions (such as breaking the skin to allow passage of a large IV catheter). The other blades have various amounts of curve in the blade. (link)

The suture needle should be passed through the skin 3-4mm from the wound edge, passing through deeper tissues aiming for the needle to exit into the wound cavity approximately 1/2 – 2/3 of the way to its base. (link)

Most skin staples are MRI compatible and although they may cause irritation due to their rigidity, they do not induce a tissue reaction. They do not usually produce as good a cosmetic result as other forms of wound closure and are more cost effective than suturing for uncomplicated scalp wounds. (link)

Fractures of ribs 1,2,11 and 12 are not usually fixed as adequate exposure is not usually possible and appears to add little to improving pulmonary mechanics or pain control. Very anterior fractures typically cannot be repaired without using either the sternum or costal cartilage as a fixation point and very posterior fractures cannot be repaired without fixation to the spine, so are usually considered unsuitable. (link)

The non union rates of scaphoid fractures are highly dependent on fracture location. These are: almost 0% with distal pole and tubercle fractures; approximately 25% for waist fractures; and approximately 60% for proximal pole fractures treated non operatively. (link)