EDAIC I MCQs (all topics) with simplified explanations. Weekly free uploads by targeredaic (2)

1. About 60% are thought to arise in deep veins of the lower extremities and pelvis
2. Pulmonary angiography is the diagnostic gold standard
3. Cyanosis is common
4. Associated bradycardia is a good prognostic sign
5. Furosemide should be given to aid oxygenation

A6: 1. FALSE 2. TRUE 3. FALSE 4. FALSE. 5. FALSE

Explanation: 90% of PE arise from lower limbs and pelvis. Tachypnoea with shallow breaths is seen in 80% of patients. Cyanosis is usually seen with massive PE. Tachycardia may relate to the site of obstruction and the onset of bradycardia is an ominous sign. It is imperative to maintain the right heart filling pressures to perfuse the lungs and maintain right ventricular output and therefore diuretics are contraindicated.

1. A force of contraction continues to rise above the maximum stimulation threshold
2. Fade is characteristic of the depolarizing blockade
3. double burst stimulation involves the use of two consecutive trains of four stimuli
4. double burst stimuli should be separated by 0.75 seconds
5. a train of four stimuli are normally delivered at 0.5

A7: 1. TRUE 2. FALSE 3. FALSE 4.TRUE 5.FALSE

Explanation: Train of four = 4 supramaximal stimuli at 2hz with a fixed pulse width of 0.2 msec. Force of contraction continues to slightly increase above the supramaximal threshold as a result of direct muscle stimulation. Therefore, delivered current should ideally be 10-20% above the threshold.
A train of four stimuli is used to detect fade on repetitive stimulation following non depolarising blockade.
Fade is due to non-depolarising blockade of prejunctional Ach receptors (which maintain Ach output with repetitive nerve stimulation )

Post tetatinic facilitation enables a response to occur when none was detectable following single twitches or T04.

The post-tetanic count consists of 5s 50hz stimulus followed by a 3s pause and then single twitches at 1Hz. The number of detectable twitches is inversely related to intensity of block.

Double burst stimulation = 3 stimuli of 50 Hz separated by 0.75s pauses.

1. Hereditary spherocytosis
2. Motor neurone disease
3. Duchenne muscular dystrophy
4. Myasthenia gravis
5. Acute intermittent porphyria

A8: 1. TRUE. 2. FALSE. 3..FALSE. 4.FALSE. 5.TRUE

Explanation: The aetiology of motor neurone disease and myasthenia gravis is unknown. Duchenne muscular dystrophy is an X linked recessive disorder. Acute intermittent porphyria presents in early adult life usually around the age of 30, women are affected more than men.

1. The commonest abnormality is an elevated INR
2. The plasma level of factor V falls in proportion to the volume transfused
3. Following a single blood volume replacement, procoagulant levels are below 20% of their normal levels
4. Diffuse microvascular bleeding is related to low procoagulant levels
5. A fibrinogen level of 100mg/dl is an indication for FFP in a bleeding patient

A9: FALSE B.FALSE C.FALSE D.FALSE E.TRUE

The arbitrary definition of a massive transfusion is the replacement of a patient’s total blood volume by stored/allogeneic blood in less than 24 hrs or the acute administration of more than 1.5 times the estimated blood volume. The most common abnormality is absolute thrombocytopenia, but there is also a dilutional, as well as an absolute fall in procoagulants and other essential components of the coagulation cascade. The platelet count falls in proportion to the volume of blood transfused, whereas plasma levels of factor V and VIII correlate poorly with transfusion volumes, the factor VII and fibrinogen levels are unrelated to transfusion volume.

The normal homeostatic mechanism can function well even with low procoagulant levels, diffuse microvascular bleeding appears to be mostly related to thrombocytopenia and severe hypofibrinogenemia. The most sensitive predictors of microvascular bleeding are a platelet count <50,000/dl,or a fibrinogen level < 0.5 g/l. For procoagulant levels to fall below 20% of their normal limits, over two times blood volume replacement is required.