Ch. 26 & 27: Anaesthetics

Question 1

Local Agents

Answer 1

• specific portion by interfering with nerve transmission or blocking nerve conduction; blocks Na+ channels and impulse conduction along axons
• do not cause loss of consciouness
• indications: minor surgical (suturing), spinal anaesthesia, dental, or diagnostic purposes (lumbar puncture)
• topical, parenteral (inflitration or nerve block)

Question 2

Lidocaine

Answer 2

• topical and injectable
• effects extended if given with epinephrine
• also used for cardiac dysrhythmias
• apply smallest amount needed, avoid applying to large areas, strenuous exercise, wraping or eating site (increase absorption)

Question 3

Local Agents: Adverse Effects

Answer 3

• occurs if agent is absorbed into circulation or injected intravascularly
• combined with vasoconsctrictors to reduce local blood flow, decrease risk of systemic absorption, prolongs anaesthesia and reduces risk of toxicity
• spinal headache, palpitations, tachycardia
• skin lesions, urticaria, edema, nervousness, hypertension
• hypotension (adrenergic blockade)

Question 4

Local Agents: Contraindictions

Answer 4

• kown allergy
• toxicity management: vasoconstrictors
• interactions: dysrythmias may occur with concurrent general anesthetic or E admin

Question 5

General Agents: Indications

Answer 5

• produce unconsciousness, muscle relaxation, and loss of responsiveness to sensory stimulation by depressing the CNS
• used with other agents to produce “balanced anaesthesia”
• surgical procedures, endoscopy, urolgic procedures, radiation therapy
• rapid onset and quickly metabolized

Question 6

General Agents

Answer 6

• inhaled: nitrous oxide
• injected: used to induce or maintain general anaesthesia and induction of amnesia
• some used in combinatio with inhaled to reduce anxiety, produce perioperative amnesia, relieve pre/postoperative pain (valium, opioids,ect.)

Question 7

Inhaled Anesthetics

Answer 7

• cause unconsciouness, analgesia, muscle relaxation, emnesia
• induction brief and pleasent
• raised or lowered with ease
• min adverse effect
• balanced anesthesia: technique employed to compensate for lack of an ideal anesthetic

Question 8

General Agents: Mechanism of Action

Answer 8

• Overton-Meyer theory: greater the solubility in fat = greater effect
• easily cross BBB and on nerve cell membranes which produce systemic reduction of sensory and CNS function
• progressive depression of cerebral and spinal cord function = unconsciousness

Question 9

General Agents: Adverse Effects

Answer 9

• dose dependent
• resp. tract, heart, peripheral circulation, liver, and kidneys
• resp. or cardiac depression, sensitization of heart to catecholamines, GI disturbances and confusion, hepatotoxicity, aspiration of gastric contents
• malignant hyperthermia

Question 10

General Agents: Contradictions and Interactions

Answer 10

• prego; narrow angle glaucoma; malignant hyperthermia (pre-treat with Dantrium)
• interactions: analgesics, CNS depressants and stimulants can influence amount required
• opioids allow for reduction
• CND depressants add to depressant effect

Question 11

Isoflurane

Answer 11

• volatile inhalation prototype
• acts quickly
• induction is usually produced with propofol
• when unconscious, depth of aneathesia cna be raised or lowered with ease
• awake about 20 mins after ceasing inhalation
• weak analgesic; use NMBA for muscle relaxation
• adverse: hypotension, resp. depression, N/V, decrease urinary output

Question 12

Nitrous Oxide

Answer 12

• low anesthetic potency; high analgesic potency
• never use as primary anesthetic
• nitrious oxide = pain relief of morphine
• no serious side effects

Question 13

Propofol

Answer 13

• IV agent
• most widely used
• unconsciousness developes in 60 seconds and lasts 3-5 mins
• sedative-hypnotic for induction and maintenance
• mechanical ventilation and procedures
• adverse: profound resp. depression, hyptoension, risk of infection; risk for abuse, instantaneous but brief sleep period; patients awaken “refreshed” and talkative; many report feeling elated and even euphoric

Question 14

Neuromuscular Blocking Drugs (NMBAs)

Answer 14

• prevent nerve transmission in certain muscles, resultingin paralysis of muscle
• used with anaesthetics during surgery: reduce amount of anesthesia needed and prevent contraction
• when used during surgery, artifical mecchanical ventilation is required due to resp muscle paralysis
• do not cause sedation or relief of pain; be paralyzed yet conscious

Question 15

NMBAs: Indications

Answer 15

• primarily for maintaining controlled ventilation during surgical procedures
• short-acting used for endotracheal intubation
• reduce muscle contraction in an area that needs surgery

Question 16

NMBAs: Contradictions

Answer 16

• previous history of malignant hyperthermia (treat with Dantrolene Sodium)
• pentrating eye injuries
• narrow-angle glaucoma

Question 17

NMBAs: Adverse effects

Answer 17

• may cause hypotension, tachycardia
• overdose: causes prolonged paralysis required mechanical ventilation
• CV collaplse may occur

Question 18

Moderate Sedation

Answer 18

• also known as conscious sedation
• IV combination of a benzodiazepine and an opiate analgesic
• reduces anxiety, relieves pain, and induces amnesia
• client can maintain their airway and respond
• rapid recovery time, enhanced client comfort, and greater client safety
• indications: diagnostic procedures and minor surgeries that do not require deep sedation