ABSITE - Anesthesia Practice Questions with Correct Answers

Local anesthetics are essential agents used in current surgical practice. Which of the following statements is true concerning the use of local anesthetic agents? A. The addition of epinephrine to a local anesthetic agent increases the toxicity and decreases the duration of local anesthesia. B. Complications caused by excessive plasma concentration can result only from inadvertent intravascular injection of the agent. C. Bupivacaine has a slow onset but a long duration D. Hypotension that occurs when a local anesthetic is administered in the form of a spinal epidural block is the result of myocardial depression Bupivacaine has a slow onset but a long duration Correct. Local anesthetics constitute a class of drugs that produce temporary blockage of nerve conduction by binding to neuronal sodium channels. Adverse consequences associated with the use of local anesthetics fall into three categories: acute central nervous system toxicity caused by excessive plasma concentration, hemodynamic and respiratory consequences caused by excessive conduction block of the sympathetic or motor nerves, and allergic reactions. Whenever a local anesthetic is injected, there can be unintentional intravascular injection or an overdose of the drug resulting from rapid uptake from the tissues. Both of these effects can cause seizures. Complications can be minimized by means of aspiration before injection to avoid intravascular injection and limiting the doses to the safe range. When local anesthetics are administered for a spinal or epidural block, progressive blockade of the sympathetic nervous system produces systemic vasodilation. If the block travels along the thoracolumbar region, sympathetic blockade results in marked systemic vasodilation and bradycardia with resultant hypotension. Local anesthetics are divided into two groups: esters and amides. The more commonly used agents, the amides, include lidocaine and bupivacaine. Lidocaine has a fast onset of action but a short duration, whereas bupivacaine has a slower onset but lasts 4 to 12 hours. Addition of epinephrine (100µg) decreases the toxicity and increases the duration of a local anesthetic. During an airway examination when the patient opens his mouth, his uvula is partially seen. This finding is called: A. Mallampati II B. Mallampati I C. Mallampati V D. Mallampati IV E. Mallampati III Mallampati II Correct. The preprocedure evaluation should include a review of current medications and coexisting disease and a brief physical examination, including evaluation of the airway. It is important to determine how difficult it may be to obtain control of the airway if apnea should occur. Although there is no absolute standard for predicting difficult intubation, a simple four-step examination helps to determine the likelihood. First, the patient should have a normal mouth opening. Second, the patient should have normal neck flexion and extension. Third, the physician should be able to fit three finger-widths under the patient's chin between the thyroid cartilage and the mentum. Finally, when the patient opens his or her mouth and is asked to stick out the tongue, the airway can be classified depending on whether the uvula can be completely seen (Mallampati class I), only partly seen (class II), not seen with only the hard and soft palate visible (class III), or only the hard palate visible (class IV). This classification is roughly predictive of progressive difficulty in intubation resulting from difficulty in visualizing the larynx.