Pain Management Part I Flashcards
Describe general anesthetics
- used for major surgeries
- induces a reversible state of unconsciousness
- provides amnesia
- often used in conjunction
Describe the ideal anesthetic
- Rapid onset
- Loss of consciousness & sensation
- Amnesia
- Skeletal muscle relaxation
- Inhibition of sensory & autonomic reflexes
- Easy dose adjustment
- Minimum toxic side effects
- Recovery rapid & uneventful
What are the stages of anesthesia
- Stage I Analgesia: still conscious, somewhat aware, loss of sensation
- Stage II Excitement: unconscious, amnesiac, appears agitated & restless
- Stage III Surgical Anesthesia: ideal level for surgery, regular & deep respirations
- Stage IV Medullary Paralysis: should be avoided, cessation of spontaneous respirations, cardiovascular collapse
Routes of administration for anesthetics
- Inhalation: gases/volatile liquids; longer onset to stage III; easier to adjust dose & maintain anesthesia
- Intravenous (IV): several categories of CNS depressants; rapid onset to stage III; risk of over medication
Describe inhalation anesthetics
- Gases: Nitrous oxide, used for short procedures
- Volatile liquids: several chemically similar agents available; Desflurane or Sevoflurane are preferred due to rapid onset, faster recovery, & better anesthesia control
Describe intravenous (IV) anesthetics
- Barbiturates: induction of anesthesia, fast onset, relatively safe
- Benzodiazepines: induction & maintain of anesthesia
- Opiod analgesics: induction & maintain of anesthesia
Describe Ketamine
- dissociative anesthesia
- pt appears detached from surroundings
- awake but sedated & unable to recall events
- useful for short procedures
Adverse effects and advantages of Ketamine
- Adverse effects: hallucinations, strange dreams, & other psychotic reactions
- Advantages: less respiratory adverse effects & less cardiac dysfunction
Describe Propofol (IV anesthesia)
- Short acting hypnotic
- Rapid onset
- Induction & maintenance
- Rapid recovery
- Continuous infusion: sedation of mechanically ventilated patients
- Rare adverse effect: Propofol related infusion syndrome (PRIS)
Describe Etomidate (IV anesthesia)
- Hypnotic like drug
- Rapid onset
- Short duration
- Quick recovery
- Minimal cardiopulmonary side effects
Describe Dexmedetomidine (IV anesthesia)
- Alpha 2 agonist
- No respiratory depression
- Adjunct during surgery
- Short term sedation for mechanically ventilated patients
- Hypotension
- Bradycardia
Describe anesthesia pharmacokinetics
- widely and uniformly distributed
- high degree of lipid solubility
- stored in adipose tissue: slow washout, longer based on duration of anesthesia or patient weight
- Elimination: excretion from the lungs, biotransformation in the liver
Describe the mechanism of action for anesthesia
- Inhibit neuronal activity in the CNS: sedation, hypnosis, amnesia
- Inhibit neuronal function in spinal cord: immobility, inhibiting motor response to painful stimuli
Describe neuromuscular blockers
- Adjunct to general anesthesia
- Skeletal muscle paralysis
- Does not provide anesthesia, sedation, analgesia, or amnesia (DO NOT USE ALONE)
Neuromuscular blockers mechanism of action
- block transmission of nerve impulses (depolarizing or non-depolarizing)
Adverse effects of neuromuscular blockers
- Tachycardia
- Increased histamine release
- Hyperkalemia
- Residual muscle pain & weakness
Physical therapy considerations with neuromuscular blockers varying washout period
- Increased confusion
- Disorientation
- Lethargy
- Delirium
- Muscle weakness
- Bronchial secretions
Describe local anesthetics (LA)
- Loss of sensation in a specific area
- Used prior to minor surgical procedures
- Rapid recovery with minimal side effects
Non- surgical use of local anesthesia (LA)
- Short term pain relief: musculoskeletal & joint pain
- Chronic pain: cancer, complex regional pain syndrome
How can a PT deliver local anesthesia (LA)
- phonophoresis
- iontophoresis
What factors go into the selection of local anesthetics (LA)
- Operative site
- Nature of procedure
- Type of regional anesthesia
- Anesthetic duration
- Patient characteristics
Describe the pharmokinetics of local anesthetics (LA)
- Drug to remain at administration site: trigeminal nerve for dental procedure; spinal cord (epidural, spinal)
- Commonly used with vasoconstrictor: epinephrine prevents “washout” from site; prevent from reaching the bloodstream (decreases systemic side effects)
- Eliminated by hydrolysis
Clinical uses of local anesthetics (LA)
- Topical
- Transdermal
- Infiltration
- Peripheral nerve block
- Central nerve blockade
- Sympathetic blockade
- Intravenous (IV) regional anesthesia
Describe topical local anesthetics (LA)
- Applied directly to produce analgesia: skin, mucous membranes, cornea
- Used for minor surface irritation or injury: burns, abrasions, inflammation
Describe transdermal local anesthetics (LA)
- Applied to skin surface
- Enhanced with electrical current (iontophoresis) and/or ultrasound (phonophoresis)
- Used in dermatologic & minor surgical procedures
- Transdermal patch: musculoskeletal pain, neuropathic pain
Describe infiltration anesthesia (LA)
- Injection directly into selected tissue
- Diffuse sensory nerve endings
- Used for performing surgical repair