Anesthetics, NMB, Narcotics, Sedatives & Anticonvulsants

1. Anesthetics, NMB, Narcotics, Sedatives & Anticonvulsants Georgia Baptist College of Nursing Kathy Plitnick RN PhD CCRN

2. Anesthetics • Anesthesia – loss of sensation with/without loss of consciousness • Analgesia - loss of pain sensation • Types of Anesthesia • General – controlled state of unconsciousness • Regional – nerve conduction is blocked to a region of the body • Local – blocking of pain impulses on peripheral nerves • Balanced – selection of several different drugs, without excessive CNS depression

3. Stages of Anesthesia • Stage of Analgesia (I): distortion of sight, hearing, numbness, analgesia • Stage of Delirium (II): loss of consciousness, involuntary activity, psychomotor excitement • Stage of Surgical Anesthesia (III): end of delirium to occurrence of apnea • Stage of Medullary Depression (IV): begins with apnea, ends with circulatory collapse

4. Parenteral Agents: Propofol (Diprivan) • Hypnotic without analgesia, amnesia • IV rapid induction, short term sedation • Rapid acting, rapid emergence • Adverse: hypotension, bradycardia, apnea • Contraindicated: soybean, egg, L&D • Nursing: • Titrate to sedation level, aseptic technique (fat emulsion), emergency equipment, “wake up” assessment, patent airway, analgesics

5. Inhalation Anesthetics • Isoflurane (Forane) –volatile liquid • Induction and maintenance – given with Nitrous oxide • Depresses all levels of CNS, skeletal muscle relaxant • Potent respiratory depressant • Minimal depression of myocardium • Potential for malignant hyperthermia • Depresses kidney function

6. Isoflurane • Post operative shivering • IV Demerol, rewarming • Monitor vs, temperature frequently • Prevent aspiration • Monitor U/O

7. Nitrous Oxide • Nonflammable, inorganic gas, colorless, odorless • Cortical depression • Good analgesic, weak anesthetic • Rapidly absorbed through lungs • Adverse: depresses cardiac contractility, hypoxia

8. Local: Lidocaine • Inhibits transport of ions across neuronal membranes • Prevents initiation & conduction of nerve impulses • Routes: topical, infiltration, mucosal, IV • Nursing: assess degree of numbness, ensure gag reflex intact after oral sprays • Infiltration: used with Epinephrine to prolong local effect

9. Neuromuscular Blockers • Cause muscle relaxation, paralyzation • Short term use: facilitate intubation, procedures in mech ventilated • Long term use: mechanical ventilation, control agitation, decrease tissue oxygen demands, increased ICP • Always administer with an analgesic &/or sedative • Patient is completely dependent • Protect the patient

10. Depolarizing Agents: Succinylcholine (Anectine) • Depolarization of motor end plates, bind to receptors • Muscle contraction appear as fasciculations (tremors) followed by muscle relaxation • Complete paralysis in 2-3 minutes • No effect on CNS

11. Succinylcholine • Adverse: stimulates vagal ganglia • Apnea • Histamine release • Increased intraocular pressure • Malignant hyperthermia • Never assume a paralyzed patient is asleep • Mechanical ventilation support

12. Nondepolarizing Agents • Block action of acetylcholine • Prevents depolarization of muscle membrane, muscle contraction cannot occur • Used in OR – to expose operative site, close wound • Anesthesiologist: facilitate intubation

13. Tubocurarine (Tubarine) • Gradual paralysis over 1-5 minutes without fasciculation • Sequence of paralysis • Persists for 40-60 minutes • Reversed by anticholinesterases • Effects: hypotension, peripheral vasodilatation, myocardial depression, reflex tachycardia, increased secretions, decreased u/o, GI motility

14. Tubocurarine • Toxic: prolonged apnea, cardiovascular collapse, recurarization • Nursing: • Hypotension profound in hypovolemia • Rehydrate • Avoid use in asthmatics • Excreted by kidneys – slower recovery or repeated doses of anticholinesterases

15. Narcotics – Morphine • Opioid analgesic, binds to opiate receptors • Alters perception to painful stimuli • Produces CNS depression • Uses: severe pain, pulmonary edema, acute MI • Available: oral, IM, IV, SC, rectal, epidural, intrathecal

16. Morphine • Adverse: confusion, sedation, respiratory depression, arrest, hypotension, constipation, urinary retention, itching, dependence • Nursing: • Assess VS, type, location & intensity of pain • Assess bowel function • Co-administration of nonopioid analgesics • Discontinue gradually • Give IVP slowly, safety precautions

17. Codeine • Mild narcotic agonist • Decreases cough reflex, GI motility • Completely absorbed from IM sites • Use Cautiously in head trauma, increased ICP, undiagnosed abdominal pain • Often combined with analgesic (ASA, tylenol) Tylenol #2 – 15 mg Codeine

18. Pentazocine (Talwin) • Narcotic Agonist-Antagonist • Antagonist properties may result in opioid withdrawal • Withdrawal symptoms: vomiting, restlessness, abdominal cramps, increased BP & temperature • Additional adverse: hallucinations, euphoria, lightheadedness • IM injections deep into well-developed muscle

19. Narcotic Antagonist – Naloxone (Narcan) • Antidote for opioid overdose • Reverses CNS depression • Results in sympathetic stimulation • IVP: 0.02 – 0.2 mg q 3-5 minutes • Always assess pain after IV Narcan • Resuscitation equipment readily available

20. CNS Depressants • Benzodiazepines: Lorazepam (Ativan) • Potentiates GABA – inhibitory NT • Sedation, amnesia • Uses: anxiety, seizures, insomnia, diagnostic procedures

21. Sleep Stages • NREM: • 1: Relaxed wakefulness • 2: Light sleep – 50% of sleep • 3 & 4: Slow wave (delta), deep restorative, secrete hormones, enhance immune function, 15-50% • REM: • Mentally, emotionally restorative • Psychological problems from deprivation • 90 minute cycles

22. CNS Depressants & REM sleep • Barbiturates • Suppress REM sleep • Rebound effect • Benzodiazepines • Do not suppress REM sleep

23. Lorazepam (Ativan) • Available oral, IM, IV (1-5 min) • Half-life 10-20 hours • Nursing: • Assess degree of anxiety • Psychological, physical dependence • Bedrest, safety precautions (IV) • Slow IVP • Avoid ETOH • Seizure management • Renal function

24. Anticonvulsant Therapy • Seizures: abnormal electrical activity in nerve cells, discharges occur in cerebral cortex • Localized areas or entire brain • Idiopathic: no specific cause • Nonidiopathic: abscess, trauma, encephalitis, CVA, uremia, ETOH, drug overdoses, sudden withdrawal, hypoglycemia, hypocalcemia, fever

25. Anticonvulsants • Block movement of sodium ions , less excitable membranes • Enhance GABA activity • Long term therapy • Oral use, IV • Stop a seizure: Lorazepam, Diazepam • Prevent seizure: phenobarbital, dilantin

26. Phenytoin (Dilantin) • Treatment/prevention tonic-clonic seizures • Alters ion transport • Absorb slowly, 18-24 hours • Steady state 1-3 weeks • Adverse: ataxia, drowsiness, hypotension, gingival hyperplasia, slurred speech

27. Phenytoin • Nursing: • Characteristics of seizure • Oral hygiene • Hypersensitivity reaction • Seizure precautions • IVP precautions • Patient identification • Urine: pink, red, reddish brown • Avoid antacids • Therapeutic levels: 10-20 mcg/ml

28. Phenobarbital • Produces CNS depression • Decreases motor activity, alters cerebellar function • Anticonvulsant activity, sedation • Uses: tonic-clonic, febrile seizures • Half-life 2-6 days • Adverse: hangover, delirium, drowsiness, excitation, hypotension

29. Phenobarbital • Frequent VS with IV use • Resuscitation equipment • Dependence • Suicide precautions • Seizure assessment, precautions • Evaluate hepatic, renal, CBC • Therapeutic level: 10-40 mcg/ml • Slow IVP

30. Anticonvulsants • Clonazepam (Klonopin): petit mal, myoclonic, long term treatment • Ethosuximide (Zarontin): absence seizures, peak levels in 3-7 hours, anorexia & gastric upset a problem • Carbamazepine (Tegretol): tonic-clonic, partial seizures, related to TCA’s, watch LFT’s, BUN, bilirubin, plt ct.