CNS Pain Meds and Anesthesia

What is the definition of pain?

A sensory and emotional experience associated with actual or potential tissue damage.

What is the most common symptom for which patients seek health care?

Pain.

What is considered the fifth vital sign?

Pain.

How is chronic pain defined compared to acute pain?

Chronic pain lasts longer than the expected recovery time.

What are the two main categories of nociceptive pain?

Somatic and visceral pain.

What type of tissues are involved in somatic pain?

Bones, muscles, and joints.

What type of tissues are involved in visceral pain?

Organs, such as the heart and liver.

What are the two main categories of neuropathic pain?

Peripheral and central pain.

What is an example of peripheral neuropathic pain?

Diabetic neuropathy.

What is an example of central neuropathic pain?

Post-stroke pain.

What is the first step in the pathophysiology of pain?

Tissue damage activates pain receptors (via heat, cold, pressure, ischemia, or chemicals) using slow and fast fibers.

What is the second step in the pathophysiology of pain?

Nociceptors transmit the signal to the spinal cord.

What is the third step in the pathophysiology of pain?

The pain signal travels to the brain stem and cerebrum.

What is the fourth step in the pathophysiology of pain?

Endorphins and enkephalins are released from the pituitary gland.

Why is pain considered subjective?

Pain is exactly what the patient says it is.

What factors can influence a patient's pain experience?

Mood, sleep disturbances, medications, age, and gender.

What are three common types of tools used to measure pain?

Numeric scales, visual scales, and observational scales.

What are examples of nonpharmacologic treatments for pain?

Massage, heat/cold therapy, physical therapy, cognitive therapy, and guided imagery.

What is the primary action of Opioid Analgesics?

They block the pain signal from getting to the brain and inhibit prostaglandins.

What level of pain are Opioid Analgesics used to relieve?

Severe to moderate pain.

What scheduling class do Opioid Analgesics fall under and why?

Schedule II, because they have medical use but a high risk of abuse.

What is multimodal pain therapy?

Using drugs from different classes to change pain, which reduces opioid use and improves outcomes.

What are four examples of Opioid Agonists?

Morphine Sulfate, Codeine, Fentanyl, and Hydromorphone.

What are the specific clinical uses for Opioid Agonists?

Relieving moderate to severe pain, acting as an antitussive (Codeine), treating heart failure/pulmonary edema (Morphine), and as adjuncts to anesthesia.

What is the onset of action for IV Opioid Agonists?

10 to 20 minutes.

What is the onset of action for PO Opioid Agonists?

60 minutes.

What are the major adverse effects of Opioid Agonists?

Respiratory depression, CNS depression, and constipation.

What is the Black Box warning for Opioid Agonists?

Respiratory failure if used with benzodiazepines or other CNS depressants, and a risk for abuse and dependence.

What are the contraindications for administering Opioid Agonists?

Respiratory compromise, liver/kidney disease, and increased ICP/head injury.

What is the reversal agent (antidote) for Opioid Agonists?

Naloxone.

How should IV Opioid Agonists be administered?

Diluted and pushed slowly (e.g., 5 mL over 5 minutes).

What clinical sign precedes respiratory depression in opioid toxicity?

Sedation.

At what sedation level (1-4) should an opioid dose be decreased or held?

Level 3 (frequently drowsy, drifts off to sleep).

At what sedation level (1-4) should Naloxone be considered?

Level 4 (somnolent).

What medications should be used with extreme caution when a patient is taking Opioid Agonists?

Other CNS depressants like antidepressants, antipsychotics, sedatives, antihistamines, and alcohol.

What patient education should be provided to manage opioid-induced constipation?

Eat a high-fiber diet, encourage fluids (2-3 L/day), and take stool softeners PRN.

How should chronic pain be dosed with opioids?

Around the clock.

What type of drug is Butorphanol?

An Opioid Agonist/Antagonist.

How does Butorphanol work?

It activates some receptors and blocks others, providing pain relief with a lower risk for abuse.

What are the uses for Butorphanol?

Second-line for moderate to severe pain, pain during labor, and perioperatively.

What is a major contraindication for giving Butorphanol?

Current use of an Opioid Agonist.

What are the immediate adverse effects of giving an Opioid Antagonist (like Naloxone)?

Withdrawal symptoms including tremors, sweating, hypertension, tachycardia, and agitation.

What is the action of Naloxone?

It reverses analgesia and displaces opioids at the receptor site.

What is Naltrexone (Vivitrol) used for?

It provides long-acting effects to treat opioid abuse.

When do opioid withdrawal symptoms start, peak, and end?

They start hours after the last use, peak at 72 hours, and last up to 10 days.

What is the priority assessment when caring for a patient receiving Morphine?

Respirations.

If a patient is difficult to arouse with a respiratory rate of 7 after IV Morphine, what is the priority action?

Administer Naloxone.

How do local anesthetics work?

They produce a local loss of sensation and motor activity by preventing cells from responding to pain and stimulation impulses.

In what exact order does a patient lose function when given a local anesthetic?

1. Temperature, 2. Touch, 3. Proprioception, 4. Muscle tone.

What is Lidocaine's mechanism of action?

It blocks nerve conduction, which blocks pain signal conduction.

What medication increases the effects of Lidocaine?

Epinephrine.

What are the adverse effects of local anesthetics?

Burning or pain at the application site, nausea/vomiting, and shivering.

What is a major contraindication for using local anesthetics?

Cardiac abnormalities and dysrhythmias.

What are three methods of administering local anesthetics?

Topical, Field Block, and Nerve Block.

How long does it take for a topical local anesthetic to work?

20 minutes.

What are the nursing considerations for applying a -caine patch (like Lidoderm)?

Apply it to the most painful area, remove the old patch and wash the site first, and do not use a heating pad over the patch.

Why must food and drink be withheld after a local anesthetic is applied to the mouth or throat?

To prevent aspiration until the gag reflex has returned.

What is the definition of General Anesthesia?

Medication-induced unconsciousness with the loss of protective reflexes.

What are the four goals of General Anesthesia?

Amnesia, analgesia, hypnosis, and immobility.

What are the three phases of General Anesthesia?

1. Induction, 2. Maintenance, 3. Emergence.

What 5 drug classes are used to achieve Balanced Anesthesia?

Benzodiazepines, Analgesics, Inhaled Anesthetics, IV Anesthetics, and Neuromuscular Blocking Agents.

What is Isoflurane used for?

Induction or maintenance of anesthesia, amnesia, muscle relaxation, and hypnosis.

What are the adverse effects of Isoflurane?

Cardiovascular and respiratory depression, airway irritation, and Malignant Hyperthermia.

What is Malignant Hyperthermia?

A genetic reaction to certain anesthetics causing tachycardia, muscle rigidity, increased temperature, sweating, and hyperkalemia.

What is the antidote for Malignant Hyperthermia?

Dantrolene.

What is Propofol used for?

Rapid induction of anesthesia (under 1 minute), amnesia, euphoria, hypnosis, and mechanical ventilation.

What are the dietary contraindications for Propofol?

Allergies to soy, eggs, or preservatives.

What is the mechanism of action for Neuromuscular Blocking Agents (e.g., Vecuronium)?

They suspend nerve impulses, leading to paralysis.

What are Neuromuscular Blocking Agents used for?

Anesthetic paralysis, muscle relaxation, intubation, and mechanical ventilation.

What is the onset and duration of Neuromuscular Blocking Agents?

Onset is 3-5 minutes, and action lasts 25-40 minutes.

What adjuvant anesthetic class produces amnesia and reduces anxiety?

Benzodiazepines (e.g., Midazolam).

What is the antidote for Benzodiazepines?

Flumazenil.

What adjuvant analgesic is 100 times stronger than morphine?

Fentanyl.

What are the common symptoms of a Migraine Headache?

Unilateral pulsing pain, vertigo, nausea/vomiting, and photophobia.

What is the physiological cause of a Migraine Headache?

Neurogenic vasodilation.

What is the action of Ergotamine tartrate?

It stimulates vascular smooth muscle to constrict cranial blood vessels.

What are the adverse effects of Ergotamine tartrate?

Cardiac effects (bradycardia, cyanosis, chest pain), musculoskeletal effects (weakness, numbness, tingling), vertigo, and nausea/vomiting.

What are the contraindications for Ergotamine tartrate?

Vascular disease, use of -azole antifungals, and macrolide antibiotics.

What is the action of Sumatriptan?

It produces cranial vascular constriction and relieves nausea, vomiting, and photophobia.

What are the adverse effects of Sumatriptan?

Dizziness, anxiety, and malaise.

When should abortive migraine medications (like Sumatriptan and Ergotamine) be administered?

At the onset of the headache.

How long might abortive migraine medications take to work?

Up to 2 hours.

What drug classes can be used for the preventative therapy of Migraine Headaches?

Beta-blockers, Calcium channel blockers, Carboxylic acid derivatives, GABA, ACE inhibitors, and Tricyclic Antidepressants.