Schedule

PBL # Overview Date Discussion Date
1 8-Sept 15-Sept
2 15-Sept 22-Sept
3 22-Sept 6-Oct
4 6-Oct 13-Oct
5 13-Oct 3-Nov
6 3-Nov 10-Nov
7 10-Nov 1-Dec

Part 1: Paralytic Agents

Background

During many types of surgery, it is common to provide muscle paralytics to patients. Two general classes of muscle paralytics are used during surgeries: depolarizing and non-depolarizing agents.

Problem

Describe the relative strengths and weaknesses of depolarizing and non-depolarizing paralytic agents. What are the criteria that an anesthesiologist would use to determine whether a depolarizing or non-depolarizing agent is better suited to a particular patient during surgery? Your answer should include a detailed description of the mechanism of action of each class of drug, and the side-effects related to that mechanism of action.

Part 2: Treatment of Myasthenia Gravis

Background

Myasthenia gravis is characterized by weakness and rapid fatigue of muscles under voluntary control.

Problem

Discuss the primary treatment for myasthenia gravis. Why is this treatment better than providing a nicotinic receptor agonist?


Background

Antiarrhythmic agents are a group of pharmaceuticals that are used to suppress abnormal rhythms of the heart, such as atrial fibrillation or ventricular tachycardia. Hundreds of drugs are classified as antiarrhythmic agents.

Antiarrhythmic agents are typically divided into five main classes, according to the primary mechanism of their anti-arrhythmic effect (Singh Vaughan Williams classification).

Problem

Discuss in detail the mechanism of action of the five main classes of antiarrhythmic agents, and which types of arrhythmias each group of drugs is used to treat. In particular, you should describe how the mechanism of action of each drug class makes it particularly useful for treating particular arrhythmias. Your answer should additionally indicate the harmful side-effects of each class of drug.


Background

Spaceflight is associated with a number of physiological alterations. Although astronauts do not report cardiovascular disturbances while in space, one consequence upon return to Earth is orthostatic intolerance, or an inability to remain in an upright posture while maintaining adequate perfusion of the brain. Orthostatic hypotension is a related condition in which blood pressure decreases, typically accompanied by tachycardia, during assuming an upright posture. As many as two-thirds of astronauts suffer from "post-spaceflight orthostatic intolerance," and the condition is so severe in about one-fourth of astronauts that they would be unable to escape from the space shuttle if an emergency arose during landing.

Problem

Explain the physiological changes that occur during spaceflight that result in post-spaceflight orthostatic intolerance. How does NASA protect astronauts against post-spaceflight orthostatic intolerance?


Background

Congestive heart failure usually results in death within two years of diagnosis, but can be managed with a variety of drugs. The treatment varies depending on whether output of the left heart lags the right heart, or the right heart lags the left.

Problem

Explain the common disease processes that result in left and right heart failure, and the medical treatments that are used to treat heart failure. You should be able to explain the physiological action of each therapy described, and how that action serves to alleviate the disease.


Background

A 61-yr-old professor comes to the family physician because he feels tired all the time. He often falls asleep when he attends seminars or lectures. Although he says he sleeps through the night (except to get up to urinate), his wife says he snores loudly and often seems to stop breathing and gasp for breath. He is restless and thrashes around in bed. He almost always wakes up with a headache, and for the past year he has been having trouble remembering things. He is 5 ft 7 in. tall and weighs 250 lb. His heart rate is 80 beats/min, his blood pressure is 135/95 mmHg, and his respiratory rate is 15 breaths/min.

Problem

Explain the cause of the symptoms in the patient. In addition, discuss how the results of the following tests would likely differ in this patient from a normal individual, and the reason the findings are abnormal:

  • Blood pH measured when patient is awake
  • Hematocrit
  • Echocardiogram
  • Electrocardiogram (ECG)
  • Spirometry

Background

A 45 year-old woman is brought to the Emergency Ward by her family because they found her to be confused. Aside from longstanding use of amitryptaline for depression, she was well, taking thiazides for mild hypertension, until she developed nausea, vomiting and abdominal cramping 4 days ago, which prevented her from eating.

Physical exam reveals:

  • Blood Pressure: 105/70
  • Heart Rate: 100
  • Respiration Rate: 18
  • Patient was afebrile
  • Cardiac exam was negative
  • Extremities were free of edema
  • Blood Chemistry:
  • Na+ 118;
  • K+ 3.1;
  • Cl- 80;
  • HCO3- 28;
  • SOSM 245;
  • UOSM 650

Problem

Explain the physiological reasons for the patient's confusion. How would you treat the patient's condition?


Background

A 66 year-old man with no significant prior illnesses presents to the Emergency Ward complaining of feeling “out of sorts.” History is notable for 50 pack years of smoking. He was seen two weeks previously in the outpatient clinic where a routine chest X-ray was obtained, which revealed a solitary 2 cm lung nodule.

Physical exam reveals:

  • Blood Pressure: 120/75
  • Heart Rate: 80
  • Respiration Rate: 16
  • Patient was afebrile
  • Cardiac exam was negative
  • Extremities were free of edema
  • Blood Chemistry:
  • Na+ 188;
  • K+ 4.2;
  • Cl- 153;
  • HCO3- 25;
  • SOSM 385;
  • UOSM 88.0

Problem

Explain the physiological reasons for the patient's feeling "out of sorts." How would you treat the patient's condition?