Short fellowship quiz 4

The usual features of each condition are as follows: CCF – Intravascular overload, urinary Na < 20mmol/L; Adrenocrtical insufficiency – volume depletion, urinary Na > 20mmol/L, decreased serum cortisol; Upper GIT losses – volume depletion, alkalosis, urinary Na < 20mmol/L; Diuretics – volume depletion, urinary Na > 20 mmol/L, normal cortisol, mild alkalosis; Skin losses – volume depletion, urinary Na < 20 mmol/L, normal pH; SIADH and hypothyroidism – euvolaemia, urinary Na > 10mmol/L, normal serum urate; Cerebral salt wasting syndrome – euvolaemia, urinary Na > 10mmol/L, low serum urate; Water intoxication – euvolaemia, urinary Na < 10mmol/L. 9Link)

The typical features of toxicity of each of the snakes is as follows: Death adder – post synaptic paralysis, local pain, no coagulopathy; Brown snake – early hypotension/cardiovascular collapse, defibrinating coagulopathy, direct renal toxicity; Mulga and Colletts – local pain and swelling, non defibrinating coagulopathy, myotoxicity; Seasnake – no coagulopathy, myopathy, neuropathy. (Link)

The approximate size of the pneumothorax is 20% (link)

A partial CN IV lesion would be expected to produce the greatest difficulty in depressing the eye when it is slightly adducted. When it is slightly abducted, the action of the inferior rectus (CN III) would predominate. (link)

Insertion of the ICC through the correctly positioned finger thoracostomy site would be preferred, if the site was not contaminated (it should not be as it was performed in another hospital, not at the crash site). Insertion above would be difficult and risks injury to axillary contents. Insertion posteriorly would risk the thoracodorsal nerve, and an anterior approach is not ideal if a haemothorax is present. (link)

The chair of the committee has responsibility for; setting the agenda; determining the order that members speak to an item; ensuring all members have the opportunity to participate (even if disruptive); determining the priorities of items for discussion; informing the committee if the nature of the item is confidential; ensuring the minutes of the meeting are accurate. (link)

Operative management is performed to try to prevent recurrent dislocation or arthritis. Usual indications include: coronoid process fractures > 50% of of the process; any displaced, intra-articular fracture; medial epicondyle fractures displaced > 10mm or associated with ulna nerve injury; a comminuted radial head fracture. (link)

The delta gap is the change in the anion gap – the change in the HCO3- concentration. It is calculated by the following formula: Delta gap = Na – (Cl+HCO3)-12- (24-HCO3), using arterial values. This results in the formula of Delta gap = Na – Cl – 36. Values > +6 indicate the presence of a metabolic alkalosis and values < -6 indicate a hyperchloraemic acidosis. The delta gap is of little practical use but appears in exams disproportionally frequently to it’s actual usefulness, so that’s why there is a question on it! (link).

Indications for immediate PTCA include: ST elevation in aVR with deeply inverted T waves in V1-4 (indicates L main occlusion and probably the strongest indication); cardiogenic shock; post cardiac arrest with ROSC;  failure of ST elevation to improve by 50% within 90 min. of commencement of thrombolytic therapy; haemodynamically significant ventricular arrhythmias resistant to treatment; ongoing pain uncontrolled by all standard therapies.(link)

Current (2013) indications for throumbolytic therapy for STEMI are for: patients presenting < 1 hour from symptom onset and PTCA is unavailable within 60 min.; patient presenting 1-3 hours of symptom onset and PTCA unavailable within 90 min.; and patient presenting 3-12 hours of symptom onset and PTCA unavailable within 2 hours. Streptokinase is contra-indicated in indigenous Australians due to the high prevalence of anti-streptococcal antibodies and potentially higher allergic reaction rate. (link)

The proportion of normal people who would be expected to have at least one abnormal result if 20 different parameters are measured is approximately 66%.The probability of an abnormal test increases exponentially with each extra test ordered. (link)

Indications for corticosteroid therapy in patients with TB include: lobar collapse secondary to lymphadenopathy; meningitis; renal TB; adrenal TB;  moribund patients. Haemoptysis alone is not an indication for steroid therapy. (link)

The left sided femoral approach would be expected to have the greatest risk of arterial puncture as the left femoral vein usually overlaps the artery to a greater extent than the right. Internal jugular approaches on either side have a lower incidence of arterial puncture than femoral approaches, when a blind technique is used. (link)

The phrase least likely to be misunderstood is the one in which the numbers are spelled out individually. Numbers from 14-19 can be misunderstood as 40 – 90 so pose a particular risk to patients. (link)

Although active cooling to 33C was previously thought to possibly be of benefit in patients with out of hospital cardiac arrest, this is no longer the case. Prevention of hyperthermia (by keeping temperatures < 37.5C) and not actively rewarming if the temperature is > 34C is the current standard. Cooling is not specifically contra-indicated in pregnancy and should be used if the patient is hyperthermic following arrest. (link)

Attempts to access the Cephalic vein in the proximal forearm is the most likely to inadvertently cannulate an artery as approximately 10% of people have a superficial radial artery at this site.

‘Hands on’ defibrillation is associated with only mild symptoms with some authors suggesting that chest compressions should not be stopped during defibrillation. (link)

The average flow rate you would expect for an infusion of crystalloid through a 16G cannula using gravity alone is 100mL/min. (link)

The longitudinal approach has the advantage of being able to directly visualise the angle of approach of the needle and ability to watch it penetrate the vessel wall without needing to move the probe. However this orientation requires a more steady hand (as the US beam is very narrow) and more space for the probe footprint (especially if a small vascular access probe is not available). The depth of the vessel from the skin can be determined using either probe orientation. (link)