Cairo: Pilbeam's Mechanical Ventilation, 6th Edition

Chapter 15: Sedatives, Analgesics, and Paralytics

WorkBook Answer Key

Key Terms Crossword Puzzle

Chapter Review Questions
1. Sedatives reduce anxiety and agitation and promote sleep and anterograde amnesia.
2. Paralysis is used to facilitate invasive procedures, such as intubation, to ensure the stability of an airway and to decrease mean airway pressure during uncoordinated or uncontrolled mechanical ventilation.
3. (a) Benzodiazepines (diazepam, midazolam, and lorazepam), (b) opioids (morphine, fentanyl), neuroleptics (haloperidol), (c) anesthetic agents (propofol), and (d) opioids (morphine, fentanyl).
4. Minimal Sedation
Patients can respond to verbal commands, although cognitive function may be impaired. Ventilatory and cardiovascular functions are unaffected.
Moderate Sedation (Conscious Sedation)
The patient can perform purposeful response following repeated or painful stimulation. (Note: Reflex withdrawal from painful stimulus is not considered a purposeful response.) Spontaneous ventilation is adequate, and cardiovascular function is usually maintained.
Deep Sedation
The patient is not easily aroused but can respond to painful stimulation. Spontaneous ventilation and maintenance of patent airway may be inadequate. Cardiovascular function is usually maintained.
Anesthesia
This level involves general anesthesia, spinal, or major regional anesthesia; local anesthesia is not included. Patient cannot be aroused, even by painful stimulation. Ventilatory assistance is typically required (i.e., artificial airway and positive-pressure ventilation). Cardiovascular function may be impaired.
5. Deep sedation may be required during the initial phases of mechanical ventilation, especially when the patient is asynchronous.
6. If sedation is necessary during weaning from mechanical ventilation, minimal levels of sedation should be used.
7. Ramsay Sedation Scale (RSS), the Motor Activity Assessment Scale (MAAS), the Sedation-Agitation Scale (SAS), and the Comfort Scale.
8. A score of 2-4 on the Ramsay scale indicates adequate sedation.
9. A score of 1 indicates the need for sedation.
10. Scores of 5-6 indicate oversedation for a patient.
11. Benzodiazepines are the drugs of choice for anxiety because of their ability to produce anxiolytic, hypnotic, muscle relaxing, anticonvulsant, and anterograde amnesic effects.
12. Benzodiazepines depress the CNS by binding to receptors in the GABA receptor complex on neurons in the brain. This increases the chloride permeability of the neuron, which in turn hyperpolarizes the neuron, making it less likely to depolarize.
13. Factors that influence the duration of action of benzodiazepines include (a) age, (b) underlying pathology, and (c) concurrent drug therapy.
14. A patient with hepatic and renal insufficiencies can have prolonged recovery from benzodiazepines.
15. Diazepam has a rapid onset of action because of its high lipid solubility and ability to traverse the blood-brain barrier relatively quickly. Onset is 3-5 minutes when the drug is administered IV.
16. IV bolus at the start of infusion, followed by a series of smaller boluses with close titration to produce the desired plasma concentration of the drug.
17. Acutely agitated patients are best treated with midazolam (Versed) because it has a rapid onset and a short half-life.
18. Prolonged sedation with midazolam can occur from accumulation of the drug and its metabolites in the peripheral tissues when it is used for longer than 48 hours.
19. Lorazepam (Ativan) is the drug of choice for use with ventilated patients for longer than 24 hours.
20. Flumazenil (Romazicon) reverses the effects of benzodiazepines; the most common side effects of flumazenil include dizziness, panic attacks, and cardiac ischemia, and it may lead to seizures in patients receiving long-term benzodiazepine or tricyclic antidepressant therapy.
21. (a) Lactic acidosis, (b) hyperosmolar coma, and (c) a reversible nephrotoxicity.
22. Neuroleptics
23. Haloperidol
24. (any of the following are a correct choice) Haloperidol has antidopaminergic and anticholinergic effects. It can induce alpha blockade, lower the seizure threshold, and evoke Parkinson-like symptoms (i.e., extrapyramidal effects, such as muscle rigidity, drowsiness, and lethargy). Dose-dependent cardiac dysrhythmias, including QT prolongation and torsades de pointes, have also been reported, particularly in patients receiving high-dose bolus IV administration of haloperidol.
25. Propofol (Diprivan) causes a reduction in systemic vascular resistance with a concomitant fall in blood pressure and bradycardia during the initial induction phase; it also reduces cerebral blood flow and ICP.
26. 
Advantages 	Disadvantages	
Rapid onset, short duration of action (makes rapid awakening possible for neurological assessment), decreased ICP, clearance unaffected by renal or hepatic dysfunction.	Hypotension, dysrhythmias, bradycardia, and elevated pancreatic enzymes. Prolonged use has been associated with lactic acidosis and lipidemia in pediatric patients. 	
27. (a) Morphine and (b) fentanyl.
28. (a) Relieve pain, (b) sedate, and (c) relieve anxiety.
29. (any of the following) Side effects of opioids include nausea, vomiting, reduced gastrointestinal motility, respiratory depression, bradycardia, hypotension, myoclonus, convulsions, histamine release, immunosuppression, and addiction.
30. The severity of these side effects depends on the dosage administered, the extent of the patient’s illness, and the integrity of organ function (i.e., renal, hepatic, and hemodynamic function).
31. Naloxone hydrochloride (Narcan)
32. Morphine’s effects on the CNS also include reduction of cerebral blood flow, intracranial pressure, and cerebral metabolic activity; drowsiness and lethargy; miosis; and suppression of the cough reflex.
33. Reduction of lower esophageal sphincter tone and propulsive peristaltic activity of the intestine, which in turn leads to constipation. Morphine can increase the tone of the pyloric sphincter and ultimately lead to nausea and vomiting by delaying the passage of contents through the GI tract.
34. Morphine can alter vascular resistance by causing a decrease in sympathetic tone and an increase in vagal tone. Reduction in vascular tone can lead to significant hypotension in patients who rely on increased sympathetic tone to maintain blood pressure.
35. Fentanyl has minimal effects on the cardiovascular system and therefore should be used for patients with an unstable hemodynamic status.
36. Morphine and propofol
37. Depolarizing NMBAs bind to acetylcholine receptors, causing prolonged depolarization of the motor end plate. Nondepolarizing NMBAs cause paralysis by competitively inhibiting the action of acetylcholine at the neuromuscular junction.
38. NMBAs are used (a) when patient-ventilator dyssynchrony cannot be corrected by adjusting ventilator settings; (b) to facilitate less conventional mechanical ventilation strategies (e.g., inverse I:E ratios, high-frequency ventilation, permissive hypercapnia); (c) when dynamic hyperinflation cannot be corrected; and (d) to reduce oxygen consumption and carbon dioxide production.
39. To assess a patient’s depth of paralysis.
40. Two electrodes are placed on the skin along a nerve path, near a hand, foot, or facial nerve. An electrical current consisting of four impulses is applied to the peripheral nerve over 2 seconds; the muscle contractions (twitches) produced provide information about the level of paralysis.
41. One or two twitches when the train-of-four test is performed indicate that an adequate amount of NMBA is being used.
42. Patients receiving an NMBA must also be given sedation, because NMBAs do not sedate the individual.
43. Succinylcholine; onset is approximately 1 minute, and its duration of action is 5-10 minutes.
44. The most common side effects associated with succinylcholine include transient hyperkalemia; cardiac dysrhythmias; anaphylactic reactions; prolonged apnea; postoperative myalgias; increased intragastric, intracranial, and intraocular pressures; myoglobinuria; and sustained skeletal muscle contraction. It may also precipitate malignant hyperthermia in susceptible individuals.
45. Pancuronium (Pavulon)
46. Vecuronium bromide (Norcuron), atracurium besylate (Tracrium), and cisatracurium besylate (Nimbex) are intermediate-duration, nondepolarizing NMBAs.
47. Prolonged paralysis after discontinuation of pancuronium can occur in patients with renal and hepatic failure. The prolonged duration of action may be partially explained by the fact that it is metabolized in the liver to an active 3-hydroxy metabolite that retains up to 50% of the activity of the parent compound.
48. Atracurium
49. Atracurium
50. Atracurium and cisatracurium
51. Cisatracurium
52. (a) Tolerance, which may necessitate increasing the dosage, and (b) muscle weakness.
Critical Thinking Questions
1. When an NMBA is used in a mechanically ventilated patient, the apnea alarm, low inspiratory pressure alarm, low exhaled VT alarm, and low exhaled minute volume alarm should be set and active. If a pulse oximeter is used continually, the low SpO2 alarm should be used.
2. Fentanyl (Sublimaze), a synthetic opioid, is the best choice for patients with asthma, because it does not cause histamine release, as morphine does. Morphine is not recommended in patients with asthma, because its mast cell–mediated histamine release may worsen bronchoconstriction.
Case Study
1. NMBA
2. The RT should switch the patient to full ventilatory support before administering an NMBA, because the patient’s diaphragm and accessory muscles will be paralyzed.
NBRC-Style Questions
1. B
2. A
3. C
4. D
5. C
6. B
7. C
8. A
9. D
10. A