New content quiz March 2014

Temperature needs to be actively managed following cardiac arrest to, at least, avoid hyperthermia which is associated with a worse neurological prognosis. Temperature control to < 36 degrees post arrest appears to be unnecessary. The role of intra-arrest cooling is yet to be defined. (Link)

Overdrive pacing is efffective in VT, but not VF – not to mention how much longer it would take to set up compared to defibrillation. (link)

Rapid, cooled IV saline is the most likely to cause a rapid reduction in termperature (c 1.2C) however is associated with a higher risk of pulmonary oedema. Ice packs to the groin and axillae are less effective at reducing temperature. The other methods mentioned will reduce temperature, but require some set up time, so are less useful in the immediate post arrest period. (link)

The strongest indication for open cardiac massage is for cardiac arrest secondary to severe poisoning (after failed medical therapy). In this situation, the heart is normal and the poisoning is usually reversible. Open cardiac massage does not produce better results than standard CPR after 20 minutes of arrest.It is less useful than ECMO (if available) in hypothermia as, unlike ECMO, it does not warm and requires interruption of cardiac compression for at least a minute. In patients with PEA and severe hypovolaemia, restoration of volume is likely to be more efffective than open cardiac massage. (link)

Systemic vascular resistance is decreased in sepsis and neurogenic shock, is usually increased in hypovolaemia and diastolic heart failure and usually normal in cardiogenic shock. (link)

Following MI one point is gained for each conduction defect: (first-degree AV block, type I second-degree AV block, type II second-degree AV block, LAHB, LPHB, RBBB, and LBBB). There is approximately a 1% risk of developing CHB with no conduction abnormality, about a 8% risk with one abnormality, a 25% risk with 2 abnormalities and a 35% risk with 2 abnormalities. (link)

The abdominal aortic tourniquet compresses the aorta against the vertebral column at the level of the bifurcation using a wedge shaped bladder placed anteriorly. Inflation of the bladder to 190 mmHg stops all flow in the common femoral arteries in 90% of people and appears to be well tolerated. It may be of use in temporary control of severe haemorrhage from junctional penetrating trauma or pelvic bleeding not controlled by pelvic binding, but is contra-indicated in abdominal trauma and trauma above the diaphragm. Severe haemorrhage below the knee would be better controlled by an above knee limb tourniquet. (link)

Cardiac arrhythmias occur in about 40% of paediatric cases of myocarditis, with approximately half of these occur after presentation. Predictors of arrhythmias on ECG are low voltages (OR 4.8) and ST changes (OR 5.9). ST elevation with Q waves, and low voltages are associated with a poor prognosis (link)

Group A Strep. is the organism associated with the greatest risk of complications (peritonsillar abscess, Rheumatic fever, Post Strep. GN). Group C and G Strep. may cause disease, but do not cause Rheumatic fever). Arcanobacterium haemolyticum is similar in presentation to Strep A., but does not cause complications. (link)

For the diagnosis of mesenteric ischaemia, an elevated D dimer is approximately 95% sensitive, 40% specific. (link)

For the diagnosis of mesenteric ischaemia, a lactate > 2mmol/L is approximately 75% sensitive, 45% specific. (link)

The accelerated protocol has a lower initial dose of NAC (100mg/kg over 2 hours vs 150mg/kg over 15-60 min), hence causes fewer early adverse effects (especially vomiting) compared to the standard protocol. It appears to have equal efficacy to the standard IV protocol, however data is limited and there may be circumstances (SR release or massive overdose) where it may be less effective due to its short duration. (link)

Red flags for fracture in patients with lower back pain include: increased age (> 65 years LR+2, > 70 years LR+ 11, even higher for females;  trauma which may be mild in those > 50 years of age and is highly suggestive of fracture (LR+30) when visible contusions are present; prolonged steroid use (LR + >10). (link)

Predictors of apnoea in bronchiolitis include: corrected age < 2 weeks (OR 10), reported apnoea at home (OR 4), respiratory rate < 30 (OR 4), respiratory rate > 70 (OR 2), oxygen saturation < 90% (OR 2), birth weight < 2.5 kg (OR 2). (link)

In non critically ill hospitalised patients, there is no clear evidence for specific blood glucose goals. Pre meal glucose concentrations of < 7.8mol/L and random concentrations of < 10mmol/L are considered reasonable. Scheduled subcutaneous insulin with estimated dose adjustment for changes in basal metabolic rate, caloric intake and other factors that may temporarily influence insulin sensitivity is the preferred method for achieving and maintaining glucose control. The use of sliding scale insulin as a sole method of controlling blood glucose is not recommended. (link)