Surprising facts Flashcards
What dosing factors increase the risk of nephrotoxicity of aminoglycosides?
Counterintuitively: higher frequency of administration (e.g., 200mg q6hr is higher risk than 400mg q12hr)
More obviously:
- high total daily dose
- duration of therapy
- high serum concentrations
How does the efficacy of celiac plexus block compare between pancreatitis vs pancreatic malignancy pain?
Neurolytic celiac plexus block for chronic, nonmalignant abdominal pain (eg, pancreatitis) appears to lack the prolonged efficacy demonstrated for the pain associated with upper abdominal malignancies. This may relate to the longer follow-up in patients with noncancer pain.
How does polycythemia affect aPTT?
Collection tubes used for PTT determination contain a specific amount of anticoagulant; failure to adequately fill the blood collection tube will result in a relative excess of anticoagulant, which may cause prolongation of the PTT. A decreased amount of plasma in the blood, as occurs with polycythemia, also may result in excess anticoagulant, resulting in prolongation of the PTT.
What is the main advantage from the addition of sodium bicarbonate to lidocaine?
Increased density of the sensory blockade.
The decreased time for the onset of analgesia is actually somewhat controversial.
Describe the clinical symptoms of diabetic cardiomyopathy.
There usually aren’t any.
Even when diabetic cardiomyopathy has progressed to heart failure, left ventricular systolic function is usually preserved; the ejection fraction is usually greater than 50%. Fewer than 50% of patients with severe systolic or diastolic dysfunction have symptoms. The only symptom may be mild exercise intolerance, and the significance of this change can be missed.
How does remifentanil affect EEG activity?
Like other opioids it will decrease BIS values but a brief infusion of very-high-dose remifentanil will decrease EEG activity in normal brain tissue but significantly increase single and repetitive spike burst activity in the epileptogenic area. This can help the surgeon localize the epilepctic focus.
What is the effect of positive lusitropy on a pressure volume loop of the left ventricle?
The slope of the line from the origin to the LVEDP (i.e., the bottom line) will decrease (i.e., become more horizontal). Patient’s with decreased lusitropy - diastolic dysfunction - will have higher LVEDP and the slope of the bottom line will be higher. The volume loop is smaller, may be moved to the left, and may be moved up due to decrease compliance
What is myotonia?
Persistent muscle contracture after voluntary contracture of the muscle.
What is the natural history of myotonic dystrophy type 1?
Onset in 2nd or 3rd decade of life. This is a disease that destroys muscle over time. Skeletal muscle affected first, followed by cardiac muscle which can result in dysrhythmias (1st degree AV block is common, can progress to complete) and increases risk of sudden cardiac death. This is followed by smooth muscle deterioration as well.
