Exam 3 Respiratory Pharmacology
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Questions and Answers

What is the effect of stimulatory G proteins on ATP in pulmonary smooth muscle when B2 agonists bind to the B2 receptor?

  • Synthesis of ATP from ADP causing smooth muscle constriction
  • Breakdown of ATP into ADP causing smooth muscle constriction
  • Conversion of ATP to cAMP causing smooth muscle relaxation (correct)
  • Conversion of ATP to cGMP causing smooth muscle relaxation
  • What is the primary use of short-acting B2 agonists?

  • Rapid relief of wheezing, bronchospasm, and airway obstruction (correct)
  • Treatment of pneumonia
  • Maintenance therapy for asthma
  • Treatment of chronic obstructive pulmonary disease (COPD)
  • What is a common side effect of B2 agonists?

  • Tachycardia (correct)
  • Hypotension
  • Bradycardia
  • Increased perfusion of poorly ventilated areas leading to transient decreases in PaO2 (correct)
  • What is the mechanism of action of anticholinergic agents in reducing bronchomotor tone?

    <p>Inhibition of binding of Ach to muscarinic receptors decreasing release of Ca+</p> Signup and view all the answers

    During exercise, which of the following occurs to increase diffusion capacity?

    <p>Recruitment of capillaries, improved V/Q, and increased alveolar ventilation</p> Signup and view all the answers

    What is the effect of Ach binding to M1 and M3 receptors in the airway?

    <p>Contraction of smooth muscle and increased mucus production</p> Signup and view all the answers

    How is diffusion capacity measured?

    <p>By having the patient inhale a known amount of CO and measuring the amount of CO exhaled</p> Signup and view all the answers

    What is the primary role of the parasympathetic nervous system (PNS) in the airway?

    <p>Regulation of bronchomotor tone</p> Signup and view all the answers

    What is the normal diffusion capacity for healthy men?

    <p>17 mL/min/mmHg</p> Signup and view all the answers

    What is the effect of edema and fibrosis on respiratory membranes?

    <p>Thicker membranes that make it harder for gases to diffuse</p> Signup and view all the answers

    What is the purpose of systemic adrenergic agents in asthma management?

    <p>For rescue therapy only</p> Signup and view all the answers

    What is the effect of emphysema on the surface area of respiratory membranes?

    <p>Decreased surface area for gas exchange</p> Signup and view all the answers

    What is the result of a 1/3 to ¼ decrease in surface area of respiratory membranes?

    <p>A serious impediment to gas exchange</p> Signup and view all the answers

    Which of the following is a common feature of both COPD and asthma?

    <p>Inflammation</p> Signup and view all the answers

    What is the effect of ketamine on pulmonary vascular resistance?

    <p>It has a mixed effect on PVR due to its ability to preserve cardiac stability but has bronchodilutory effects</p> Signup and view all the answers

    What is the effect of N2O on pulmonary vascular resistance?

    <p>It can cause pulmonary artery vasoconstriction due to catecholamine release - avoid in PHTN</p> Signup and view all the answers

    What is the effect of volatile inhalation agents on pulmonary vascular resistance?

    <p>They have little to no effect on PVR</p> Signup and view all the answers

    What is the effect of fentanyl on the deleterious effects of N2O?

    <p>It offsets the deleterious effects of N2O at a dose of 50 mcg/kg... but that's not a great idea</p> Signup and view all the answers

    What is a common side effect of Methylxanthines?

    <p>Diuresis, seizures, dysrhythmias, and death - these drugs have a narrow therapeutic index</p> Signup and view all the answers

    What is a characteristic of intermediate acting NMBers such as rocuronium, cis-atracurium, and vecuronium?

    <p>They are known for their cardiac stability and are unlikely to cause histamine release</p> Signup and view all the answers

    Which of the following neuromuscular blockers is least likely to cause histamine release?

    <p>Cis-atracurium</p> Signup and view all the answers

    What is the effect of pancuronium on heart rate?

    <p>It increases heart rate through an antagonistic effect on muscarinic receptors</p> Signup and view all the answers

    What is the effect of sympathetic activation on pulmonary vascular resistance?

    <p>It increases pulmonary vascular resistance</p> Signup and view all the answers

    What is the primary mechanism of action of inhaled nitric oxide?

    <p>It decreases intrapulmonary shunt because nitric oxide is preferentially delivered to ventilated lung units</p> Signup and view all the answers

    What is a potential complication of inhaled nitric oxide therapy?

    <p>Methemoglobinemia</p> Signup and view all the answers

    What is the primary mechanism of action of phosphodiesterase inhibitors?

    <p>They decrease the breakdown of cAMP and cGMP, leading to vasodilation</p> Signup and view all the answers

    What is the effect of decreased cardiac output on systemic concentrations of inhaled anesthetics?

    <p>Abrupt increase due to slowed blood flow allowing for increased absorption</p> Signup and view all the answers

    What is the effect of age on MAC?

    <p>MAC is inversely affected by age</p> Signup and view all the answers

    What is the effect of pregnancy on MAC?

    <p>MAC decreases during pregnancy and returns to baseline in 12-72 hours</p> Signup and view all the answers

    What is the effect of red hair coupled with female gender on MAC?

    <p>MAC increases in red hair coupled with female gender</p> Signup and view all the answers

    What is the effect of opioids on inhaled anesthetic requirements?

    <p>Opioids synergistically reduce inhaled anesthetic requirements (i.e. increase potency/lower MAC)</p> Signup and view all the answers

    What is the effect of sevoflurane on kidney function?

    <p>When sevoflurane is exposed to CO2 absorbents, it can produce compound A which is nephrotoxic</p> Signup and view all the answers

    What is the effect of halothane on the heart?

    <p>Halothane sensitizes the heart to the arrhythmogenic effects of catecholamines</p> Signup and view all the answers

    What is the effect of isoflurane, desflurane, and sevoflurane on mean arterial pressure?

    <p>They decrease mean arterial pressure due to decreases in systemic vascular resistance</p> Signup and view all the answers

    What happens to the concentration of inhaled gas in the systemic circulation when cardiac output is elevated?

    <p>It decreases, resulting in delayed induction</p> Signup and view all the answers

    What is the effect of a high cardiac output on the delivery of parenterally (IV) administered anesthetic agents to the systemic circulation?

    <p>It speeds up their delivery.</p> Signup and view all the answers

    Which of the following anesthetics reduce bronchomotor tone?

    <p>Ketamine, propofol, and midazolam</p> Signup and view all the answers

    When were ether and nitrous oxide broadly used as anesthetics?

    <p>Initially in the mid-19th century and broadly used in the World Wars</p> Signup and view all the answers

    When was halothane first used as an anesthetic?

    <p>1955</p> Signup and view all the answers

    When were enflurane and sevoflurane first used as anesthetics?

    <p>1970s and 1980s</p> Signup and view all the answers

    What agents are typically used as a first-line treatment in the management of asthma?

    <p>Long acting Beta2 agonists and corticosteroids</p> Signup and view all the answers

    What agents are typically used as a first-line treatment in the management of COPD?

    <p>Anticholinergics and steroids</p> Signup and view all the answers

    What is the primary difference in White Blood Cells (WBCs) present in asthma and COPD?

    <p>Eosinophils are more prevalent in asthma, while neutrophils are more prevalent in COPD</p> Signup and view all the answers

    What drug class is methylxanthine?

    <p>Non-selective phosphodiesterase inhibitor</p> Signup and view all the answers

    What is the mechanism of action of non-selective phosphodiesterase inhibitors?

    <p>Increase in cAMP, inhibits release of histamines/leukotrienes, and inhibits phosphodiesterase leading to bronchodilation</p> Signup and view all the answers

    What is the mechanism of action for mast cell stabilizers?

    <p>Inhibition of histamine release from mast cells</p> Signup and view all the answers

    Mast cell stabilizers are used for asthma, not COPD

    <p>True</p> Signup and view all the answers

    In what stage of COPD are inhaled corticosteroids used in combination with long-acting beta2 agonists to synergistically reduce inflammation?

    <p>Severe to very severe COPD</p> Signup and view all the answers

    What is the mechanism of action of corticosteroids?

    <p>Corticosteroid binds to glucocorticoid receptor and reducing expression of inflammatory gene products</p> Signup and view all the answers

    What is the primary effect of leukotrienes in the lung?

    <p>Bronchoconstriction and increased permeability</p> Signup and view all the answers

    What is the main difference between leukotriene inhibitors and leukotriene antagonists?

    <p>Leukotriene inhibitors prevent the synthesis of leukotrienes, while leukotriene antagonists block the action of leukotrienes at the receptor.</p> Signup and view all the answers

    Leukotriene modifiers are used in long term asthma therapy

    <p>True</p> Signup and view all the answers

    What is true about Ipratropium in COPD?

    <p>It is a short-acting medication used for maintenance therapy.</p> Signup and view all the answers

    What is ipatropium typically used for?

    <p>Rescue therapy in COPD and asthma exacerbations</p> Signup and view all the answers

    What is true about tiotropium?

    <p>It is a long-acting medication used for COPD maintenance therapy</p> Signup and view all the answers

    What are the effects of increases in cAMP on vasculature?

    <p>Vasodilation and decreased blood pressure</p> Signup and view all the answers

    What is the regulatory effect of cAMP and Ca(2+) on vascular smooth muscle tone?

    <p>Rising levels of Ca(2+) lead to vasoconstriction, whereas an increase of cAMP induces vasodilatation</p> Signup and view all the answers

    How does cyclic GMP activate protein kinase G in relation to bronchodilator pathways?

    <p>By linking to the cAMP pathway</p> Signup and view all the answers

    What is a risk of prolonged use of beta2 agonists?

    <p>Tachyphylaxis due to downregulation and desensitization</p> Signup and view all the answers

    Autonomic NS and Non-adrenergic non-cholinergic (NANC) system influence bronchomotor tone

    <p>True</p> Signup and view all the answers

    What drugs are commonly used for emergency or acute exacerbations of COPD and asthma?

    <p>All of the above</p> Signup and view all the answers

    What is the pulmonary first pass effect?

    <p>The metabolism of a drug within the lungs before reaching systemic circulation</p> Signup and view all the answers

    What is the primary site of uptake for fentanyl and lidocaine?

    <p>Pulmonary uptake (90% fentanyl and 50% lidocaine)</p> Signup and view all the answers

    What is the role of ACE in maintaining blood pressure?

    <p>ACE increases blood pressure by converting angiotensin I to angiotensin II which stimulates vasoconstriction</p> Signup and view all the answers

    Where is most angiotensin-converting enzyme concentrated in the human body?

    <p>Lungs</p> Signup and view all the answers

    What drugs are contraindicated for use in pulmonary hypertension?

    <p>Nitrous oxide and catecholamines</p> Signup and view all the answers

    What drug types are pulmonary vasodilators?

    <p>All of the above</p> Signup and view all the answers

    What drives movement of air during ventilation?

    <p>Pressure gradient</p> Signup and view all the answers

    What difference drives gas exchange at the alveolar level during respiration?

    <p>Concentration gradient</p> Signup and view all the answers

    What does Henry's Law state about the partial pressure of an anesthetic?

    <p>The partial pressure of an anesthetic in blood is proportional to the partial pressure of the anesthetic in alveoli</p> Signup and view all the answers

    What is the source of energy for diffusion in the respiratory system?

    <p>Molecular kinetic energy</p> Signup and view all the answers

    What factors determine the diffusion coefficient of a substance according to Graham's Law?

    <p>Solubility and molecular weight</p> Signup and view all the answers

    What does the diffusion coefficient represent?

    <p>The relative rates at which different gases at the same partial pressure levels will diffuse</p> Signup and view all the answers

    What factors influence the movement of gas once it's at the alveolus?

    <p>All of the above</p> Signup and view all the answers

    According to the partial pressure gradient, which direction will oxygen diffuse in the alveoli?

    <p>From higher partial pressure in the the gas phase in alveoli to the lower pressure areas in the blood</p> Signup and view all the answers

    Why does CO2 diffuse from the blood into the alveoli?

    <p>The partial pressure of CO2 is higher in the blood than in the alveoli</p> Signup and view all the answers

    What is the relationship between alveolar PCO2 and alveolar ventilation?

    <p>They vary inversely</p> Signup and view all the answers

    Oxygen concentration in the alveoli and partial pressure is a function of which of the following? (Select 2)

    <p>Rate of absorption into the blood</p> Signup and view all the answers

    What is unique about the weight of oxygen as compared to the weight of CO2?

    <p>CO2 is heavier than oxygen so it moves slower</p> Signup and view all the answers

    Which of the following statements about gases of respiratory importance is FALSE?

    <p>Gases of respiratory importance are not highly soluble in lipids</p> Signup and view all the answers

    What is the limiting factor in the diffusion of gases in tissues?

    <p>The rate in which the gas diffuses through water</p> Signup and view all the answers

    Air (i.e. N+O+CO2) is almost totally humidified before reaching the alveoli

    <p>True</p> Signup and view all the answers

    How does water vapor affect the partial pressures of gases in air?

    <p>It dilutes all gases, driving their partial pressures down</p> Signup and view all the answers

    If oxygen has a diffusion coefficient of 1, what would be the diffusion coefficient of CO2?

    <p>20</p> Signup and view all the answers

    What is unique about the concentrations of oxygen and CO2 of alveolar air as compared to expired air?

    <p>Alveolar air has a lower oxygen concentration and a higher CO2 concentration compared to expired air.</p> Signup and view all the answers

    Why does expired air have more oxygen than alveolar air?

    <p>Expired is partially comprised of air that has never made it deep enough in the lungs for the oxygen to be absorbed into the blood</p> Signup and view all the answers

    What is a characteristic of alveolar air?

    <p>It is only partially replaced by atmospheric air with each breath</p> Signup and view all the answers

    What is the importance of slow replacement of alveolar air?

    <p>It prevents sudden changes to gas concentrations in blood</p> Signup and view all the answers

    Multiple breaths are required to exchange alveolar air due to the difference between FRC (2300mL) and alveolar volume (350mL)

    <p>True</p> Signup and view all the answers

    Expired air = dead space air + alveolar air

    <p>True</p> Signup and view all the answers

    Why does expired air have the gas concentrations that it does?

    <p>Due to the combination of dead space air and alveolar air, putting concentrations in the areas between the two</p> Signup and view all the answers

    Dead space air = anatomic dead space air + alveolar dead space air

    <p>True</p> Signup and view all the answers

    What is dead space air in the respiratory system?

    <p>Air that does not participate in gas exchange and does not come into contact with the alveoli</p> Signup and view all the answers

    What is alveolar dead space air?

    <p>Air in alveoli that are ventilated but not perfused</p> Signup and view all the answers

    When alveoli are ventilated but not perfused, the V/Q = infinity

    <p>True</p> Signup and view all the answers

    When alveoli are perfused but not ventilated, the V/Q = 0

    <p>True</p> Signup and view all the answers

    When alveoli are ventilated but not perfused, what does the alveolar air equilibrate to?

    <p>inspired air</p> Signup and view all the answers

    When alveoli are perfused but not ventilated, what does the alveolar air equilibrate to?

    <p>Mixed venous blood</p> Signup and view all the answers

    What are the partial pressures of O2 and CO2 when ventilation and perfusion are matched?

    <p>O2: 104 mmHg, CO2: 40 mmHg</p> Signup and view all the answers

    What are the partial pressures of O2 and CO2 when V/Q=0?

    <p>P O2 = 40 mmHg, P CO2 = 45 mmHg</p> Signup and view all the answers

    What are the partial pressures of O2 and CO2 when V/Q = infinity?

    <p>PO2 = 149mmHg, PCO2 = 0 mmHg</p> Signup and view all the answers

    Dead space air has no CO2.

    <p>True</p> Signup and view all the answers

    What is a shunt in the context of respiratory physiology?

    <p>Blood passing through the pulmonary vasculature and not oxygenated, resulting in underventilated alveoli</p> Signup and view all the answers

    What is the V/Q ratio in a shunt?

    <p>V/Q below normal because perfusion exceeds ventilation</p> Signup and view all the answers

    In dead space ventilation, what is the outcome of the work of ventilation?

    <p>It never makes it to the blood, therefore &quot;wasting&quot; alveolar ventilation</p> Signup and view all the answers

    In which type of ventilation does ventilation exceed perfusion (VQ is greater than normal)?

    <p>Dead space ventilation</p> Signup and view all the answers

    What comprises physiologic dead space?

    <p>Anatomical dead space and alveolar dead space</p> Signup and view all the answers

    What respiratory consequence can result from smoking?

    <p>Increased shunt and dead space ventilation secondary to obstruction</p> Signup and view all the answers

    What is unique about the MAC when combining two inhaled agents?

    <p>The MAC is additive</p> Signup and view all the answers

    What determines the concentrations and partial pressures of O2 and CO2 in the alveoli?

    <p>Rate of absorption and excretion of O2 and CO2, and amount of alveolar ventilation</p> Signup and view all the answers

    What are the factors that determine the rate of diffusion through the respiratory membrane?

    <p>Thickness of membrane, surface areas of membrane, diffusion coefficient, and partial pressure difference</p> Signup and view all the answers

    When was desflurane first used?

    <p>1992</p> Signup and view all the answers

    Study Notes

    Diffusion Capacity

    • Diffusion capacity is the volume of gas that will diffuse through the membrane per minute per 1 mmHg partial pressure difference
    • Increased during exercise due to recruitment of capillaries, improved V/Q, and increased alveolar ventilation
    • Can be estimated using diffusion capacity for CO (DLCO)
    • DLCO in healthy men = 17 mL/min/mmHg

    Factors Affecting Diffusion Rate

    • Thickness of membrane: thicker membranes (edema, fibrosis) make it harder for gases to diffuse
    • Surface area of membrane: decreased surface area (emphysema) impedes gas exchange
    • Diffusion coefficient and partial pressure difference also affect diffusion rate

    Respiratory Pharmacology

    Inhaled Beta-2 Agonists

    • Bind to beta-2 receptor in pulmonary smooth muscle, leading to smooth muscle relaxation and bronchodilation
    • Short-acting (albuterol, levabuterol, metaproterenol, pirbuterol) for rapid relief of wheezing, bronchospasm, and airway obstruction
    • Long-acting (salmeterol, formoterol, aformoterol) for maintenance therapy
    • Side effects: tremors, tachycardia, temporary decrease in PaO2, tolerance due to downregulation and desensitization

    Anticholinergic Agents

    • Not used for asthma maintenance
    • Act on M1 and M3 receptors in airway to reduce tone
    • Inhibit binding of Ach to muscarinic receptors, reducing smooth muscle tone and mucus production
    • M1 and M3 receptors produce bronchoconstriction and mucus production when bound by Ach

    COPD and Asthma

    • Shared feature: inflammation
    • Asthma: mast cells, COPD: neutrophils
    • COPD has a more pronounced inflammatory response

    Pulmonary Artery Pressure

    • NMDA receptor antagonists (e.g. ketamine): stimulate release and inhibit uptake of catecholamines, causing cardiostimulatory and bronchodilatory effects
    • Volatile inhalation agents and N2O: little to no effect on pulmonary vascular resistance, but decrease bronchomotor tone
    • Neuromuscular blocking agents: unlikely to cause histamine release, but can increase HR
    • Vasopressors and inotropes: sympathetic activation increases PVR
    • Nitric oxide (NO): preferentially delivered to ventilated lung units, decreasing intrapulmonary shunt
    • Phosphodiesterase inhibitors: decrease metabolism and breakdown of cAMP and cGMP, causing vasodilation and enhancing NO effects

    Volatile Inhalation Agents and N2O

    • Relative potency (MAC): lower the MAC, the higher the potency
    • Immobility is how potency is measured
    • Blood gas coefficient: lower the BGC, the faster the onset and emergence
    • Determinants of alveolar partial pressures: cardiac output, co-existing disease, and co-administration of other pharmacologic agents
    • Factors influencing MAC: age, pregnancy, red hair, and opioids
    • MAC values for inhaled anesthetics are additive

    Complications of Inhalation Agent Administration

    • Cardiac dysrhythmia: halothane has a risk of cardiac depression and VT
    • Hepatic disease: halothane has a risk of postoperative hepatic dysfunction
    • Kidney injury: enflurane and sevoflurane can cause nephrotoxicity
    • Hypotension: decreases in MAP due to decreases in SVR with isoflurane, desflurane, and sevoflurane

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    Description

    Test your knowledge of respiratory physiology, including diffusion capacity, gas exchange, and ventilation. This quiz covers key concepts related to the respiratory system and its functions.

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