Ch. 26 & 27: Anaesthetics Flashcards Preview

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Flashcards in Ch. 26 & 27: Anaesthetics Deck (18):

Local Agents

- 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)



- 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)


Local Agents: Adverse Effects

- 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)


Local Agents: Contraindictions

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


General Agents: Indications

- 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


General Agents

- 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.)


Inhaled Anesthetics

- 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


General Agents: Mechanism of Action

- 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


General Agents: Adverse Effects

- 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


General Agents: Contradictions and Interactions

- 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



- 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


Nitrous Oxide

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



- 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


Neuromuscular Blocking Drugs (NMBAs)

- 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


NMBAs: Indications

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


NMBAs: Contradictions

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


NMBAs: Adverse effects

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


Moderate Sedation

- 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