Understanding Pain Management

Pain Management

• Pain is an unpleasant sensory and emotional experience related to actual or potential tissue damage.
• Pain is subjective and influenced by biological, psychological, and social factors.
• Pain classifications include duration, location, and etiology.

Duration of Pain

• Acute pain has a rapid onset and short duration, usually lasting less than 3-6 months.
• Acute pain has an identifiable cause, varies in intensity, gradually resolves, and serves a protective function.
• Chronic pain is persistent, lasts longer than 6 months, and disrupts activities of daily living (ADLs).
• Chronic pain no longer serves to protect, degrades health and functional capability, and is often associated with psychological comorbidities.
• Chronic pain may involve remission and exacerbation.

Location of Pain

• Cutaneous pain is superficial, involving the skin or subcutaneous tissue. An example being pain experienced from a paper cut or burning sensation.
• Somatic pain is diffuse and scattered, affecting bones, tendons, ligaments, and muscles. Sprains and arthritis are examples.
• Visceral pain is poorly localized and originates in body organs due to distension, ischemia, or inflammation.
• Referred pain originates in one area but is felt in another, for example, MI presenting as neck, jaw, or arm pain.

Etiology of Pain

• Nociceptive pain is initiated by nociceptors, activated by actual or threatened damage.
• Nociceptive pain can be somatic (localized, intermittent or constant, aching, gnawing, cramping)
• Nociceptive pain can be visceral (from internal organs)
• Neuropathic pain is caused by lesion or disease, originating peripherally or centrally.
• Neuropathic pain can be short in duration but frequently chronic and is described as burning, tingling, or stabbing.
• Neuropathic pain examples include complex regional pain syndrome, post-herpetic neuralgia, phantom limb pain, diabetic neuropathy, and trigeminal neuralgia.
• Nociplastic pain is a combination with no clear evidence of actual or threatened tissue damage.

Pain Process

• The four physiological processes involved in nociception are transduction, transmission, perception, and modulation.

Transduction

• Involves activation of pain receptors by mechanical, thermal, chemical, or electrical stimulation.
• Painful stimuli are converted into electrical impulses.
• Impulses travel from the periphery via nociceptors to the spinal cord through the dorsal horn.
• Sensitization is a response to prolonged stimuli effects.
• Chemical response to injury involves histamine, lactic acid, bradykinin, substance P, prostaglandins, and serotonin.
• Histamine is released by cells and involved in allergic inflammatory reactions.
• Lactic acid accumulates in injured tissues and excites nerve endings.
• Bradykinin is a vasodilator that increases permeability and constricts smooth muscle.
• Substance P sensitizes receptors and increases nerve firing.
• Prostaglandins are hormone-like substances that send additional pain stimuli to the CNS.
• Serotonin stimulates smooth muscles, inhibits gastric secretions, and produces vasodilation.

Transmission

• Pain sensations are transmitted from the injury site along pathways to the spinal cord.
• Free nerve endings receive painful stimuli, and there are no specific organs or pain cells.
• A-delta fibers are afferent, large, fast, and acute, transmitting well-localized pain such as burning, thermal, aching, and mechanical pain.
• C-fibers are small, slow, and transmit diffuse, longer-lasting pain, including chemical or persistent mechanical or thermal pain.

Perception

• Perception involves sensory processes when a pain stimulus is present and includes the person's perception of pain.
• Pain threshold is the lowest intensity of a stimulus that causes pain to be recognized.
• Pain threshold adaptation can change.

Modulation

• Processes inhibit or modify pain sensations controlled by neuromodulators include endorphins and enkephalins.
• Endogenous opioid-like substances provide analgesic effects by binding to opioid receptor sites.
• Endorphins, present along the CNS pathway, are pain blockers and produce euphoria.
• Enkephalins inhibit substance P release, reducing pain sensation.

Gate Control Theory

• Widely accepted theory explaining pain mechanism.
• Explains why different people interpret similar painful stimuli.
• Mechanical and electrical interventions and heat or pressure may provide effective relief.
• Gate control theory asserts non-painful input closes nerve "gates," preventing pain sensation travel to the central nervous system
• Stimulation by non-noxious input suppresses pain.
• The theory states that only a limited amount of information is processed at a time.
• A balance of excitatory and inhibitory nerve fibers controls the dorsal horn of the spinal cord.

Response to Pain

• Response to pain can be physiologic, behavioral, and affective.

Physiological Responses

• Are involuntary, and can manifest as increased BP, HR, RR
• Pupils dilate, muscle tension/rigidity occurs
• Vasoconstriction with peripheral pallor emerges, and adrenalin and blood glucose increase.
• Other results include perspiration, nausea/vomiting, and fainting.
• With severe pain, BP and HR drop with rapid/irregular RR.

Behavioral Responses

• Are reflected with body movements:
• Posture and facial expressions show withdrawal, restlessness, grimacing, clenching, groaning, moaning, crying, protecting area/guarding.

Affective Responses

• Center on mood and emotions
• A patient is influenced by social and cultural norms and expectations that are challenging to interpret with mental illness or cognitive disability.
• This includes weeping, restlessness, stoicism, anxiety, depression, fear, interactions with others, perception of illness, anger, anorexia, fatigue, hopelessness, powerlessness, and insomnia.

Lifespan Considerations for Elders

• Pain is not a normal part of aging, but is one of the most common health conditions
• It's associated with significant disability and mobility.
• Assess for functionality of ADLs, and consider alternatives
  • Vision and hearing impairments should be considered
  • Poly-pharmacy should be kept in mind
  • Patients are reluctant to report pain views as a forecast of serious illness or death - Mental health- boredom, loneliness, and depression can alter their pain perception

Pain Assessment

• A critical nursing competency requiring practice and conscious effort.
• Assess all pain domains, physical, psychological, social, and spiritual.

Pain History

• Includes:
  • Onset and duration
  • Etiology if known
  • Location: local, general, radiation
  • Characteristics: sharp, dull, diffuse, shifting, cutting, throbbing, sore
  • Intensity/quantity: 0-10
  • Periodicity: continuous, intermittent, brief, transient
  • Aggravating and alleviating factors
  • Associated factors: anxiety, fear, insomnia
  • Interference with activities: ADLs, work
  • Pain management goal

OPQRST Assessment

• O- onset: circumstances of the start (gradual or sudden).
• P- provoking: Actions and conditions make it feel better or worse.
• Q- quality: Description of pain (sharp, burning, numb).
• R- radiation/Region: Location and if the pain travels.
• S- severity: Rate the pain on a scale of 0-10.
• T- time: How long ago did the pain start

Factors Affecting Pain Experience

• Pain is a highly individual, unique, and personal experience
• It's influenced by many factors:
  • Patient's background
  • Previous experiences
  • Culture and ethnicity
  • Age, gender, faith
  • Environment, support, and anxiety

Pain Assessment Tools

• Use the appropriate tool, as no single one is effective for all patients.
• Consider vulnerable populations like infants, children, the elderly, cognitively impaired, and nonverbal persons.
• Numeric Reporting Scale (NRS): Adults and children >9 in all settings
• Visual Analog Scale: Adults and children >9 in all settings
• Wong-Baker Faces Pain Scale: Adults and children in all settings.
• FLACC: Infants and children who are unable to validate or quantify pain.
• PAINAD: Patients with advanced dementia.
• CPOT: Critical care pain observation tool for adults sedated and nonresponsive.

Fluids and Electrolytes

Homeostasis

• Intake and output are about equal for balance to maintain healthy body functioning
• Maintained by the constant movement of water and solutes between body fluid compartments
• Fluid is 50-60% of body weight.

Distribution of Fluids

• Intracellular
  • Insides of cells
  • 70% of total body water and 40% of adult body weight
  • Contains oxygen, electrolytes, and glucose
• Extracellular
  • Outside of cells
  • 30% of total body water and 20% of adult body weight
  • Intravascular
    • blood vessels and plasma
  • Interstitial Fluid
    • Surrounds cells, including lymph
    • Waste transportation
• Transcellular
  • Cerebrospinal, pericardial, synovial, intraocular, pleural, sweat, and digestive secretions

Age Considerations

• Elders
  • Structural changes to kidneys
  • Reduced thirst mechanisms
  • Medications
  • Medical conditions
• Infants
  • More total body fluid and ECF
  • More prone to fluid volume deficits
• Fat cells
  • Contain little water
  • More body fat in women
  • The elderly have an increase in fat cells
  • Less total body fluid in more fat cells

Water

• Transports nutrients to cells, and wastes from these
• Transports hormones, enzymes, blood- RBC, WBC, and platelets
• Facilitates cellular metabolism and proper chemical functioning
• Acts as a solvent for nutrients and oxygen, maintaining body temperature
• Aids in digestion, elimination, joint, and tissue lubrication

Regulation of Fluid Intake

• Intake is regulated by the thirst mechanism found in the hypothalamus
• It's regulated by:
  • Intracellular dehydration
  • Decreased blood volume
  • Concentration of serum sodium
• May not be effective in adults and children, causing dehydration

Assistants of Homeostasis

• Kidneys
  • Normally filter 180L of plasma, excreting 1.5L urine per day
  • Selective in retention and excretion
• Cardiovascular
  • Circulates nutrients and water
  • Circulates blood through kidneys
• Skin excretes 300-500mL water/day
• Lungs
  • Excrete 300mL water/day
  • Regulate oxygen and carbon dioxide
  • Maintain acid-base balance
• Endocrine
  • Thyroxine
    • Thyroid gland
    • Increases blood flow to the body
    • Increases renal circulation, glomerular filtration, and urinary output
  • Antidiuretic Hormone (ADH)
    • Made in the hypothalamus
    • Stored in the posterior pituitary
    • Promotes water reabsorption
  • Aldosterone
    • Secreted by adrenal cortex
    • Promotes sodium and water reabsorption and potassium excretion
• Enzymes
  • Renin
    • Responds to altered renal blood flow
    • Decreased renin causes peripheral vascular constriction and aldosterone release
• GI Tract
  • Absorbs water and nutrients
• Lymphatics
  • Plasma protein shifts to tissue
• Nervous
  • A switchboard to inhibit and stimulate fluid balance
  • Neurons
    • Sensitive change in the concentration of ECF
    • Sends signals for alteration of ADH
• Fluid Intake and Loss
  • Should be equal
  • Average 2500-2600mL per day
  • Should be achieved in 2-3 days
    • Water 1500ml --> Kidney 1500mL
    • Food 800mL --> Skin 600mL
    • Metabolic oxidation 300ml --> Lungs 400mL --> GI 100 mL
    • Totals: 2600 mL

Movement of Fluids

• Solute
  • Substance dissolved in a solution, like electrolytes and nonelectrolytes
• Solvent
  • Liquids that contain substances in solution, water is the primary solvent in the body
• Transportation of Fluids and Electrolytes
  • Osmosis, diffusion, active transport, and filtration

Osmosis

• Solvent passes from lesser to a greater solute concentration area until equilibrium

Osmolarity

• Influences the movement of fluid
• Measured using serum osmolality to find the measurement of a solution's total solute concentration
  • Normal being 280-295 mOsm/kg
  • Primarily determined by glucose and urea particles
• Fluids are categorized relative to serum osmolality: isotonic, hypertonic, and hypotonic.

Diffusion

• Solute moves from a higher to a lower concentration area until equilibrium is achieved
• Solutes move freely
• The exchange of oxygen and carbon dioxide is by diffusion

Active Transport

• Energy is required for movement through a cell membrane from lesser to a greater concentration area
  • Adenosine triphosphate supplies energy for solute to move
  • Substances requiring active transport:
    • Amino acids
    • Glucose
    • Sodium, potassium, hydrogen, and calcium

Filtration

• Passage of fluid through a permeable membrane from higher to lower pressure
  • Capillary filtration with blood pushing against capillary walls
  • Hydrostatic pressure is the pushing force
    • Pressure inside the capillary exceeding interstitial space forces fluids out
  • Colloid Osmotic Pressure (Oncotic Pressure) pulls the fluid

Fluid Status Indicators

• Body and daily weight
• Osmolality
  • Urine
    • Increases with Fluid Volume Deficit, prerenal failure, and heart failure
    • Decreases with hyponatremia, Fluid Volume Excess, and diabetes insipidus
  • Serum
    • Increases with hyperglycemia, hypernatremia, and in severe dehydration
    • Decreases with renal failure, diuretic use, and Fluid Volume Excess
• Blood urea nitrogen (BUN) of creatinine
• Urine-Specific gravity
  • The measurement of chemicals in the urine
  • It reflects the ability of the kidneys to concentrate urine, affecting the number and size of particles - like minerals

FVD Fluid Volume Deficit

• Hypovolemia
  • When output is not balanced by increased intake
    • Vomiting, diarrhea, GI suction, hemorrhage, overuse of diuretics, wounds, burns, and lack of aldosterone
    • Excessive sweating, and Dehydration or lack of water and salt intake
    • Shifts from intravascular to the third space
      • Acute intestinal Obstructions, ascites, burns and surgeries
  • Clinical Manifestations
    • Mild 2% loss
    • Marked 5% loss
    • Severe dehydration 20-30% loss of TBW
  • Clinical Presentation includes weakness, fatigue, dizziness, muscle cramps, and thirst
  • Assessment requires a look out for mucous membranes, decreased skin integrity, hypotension, and high blood pressure
    • Hypotension and tachycardia
    • History of what causes the reading
    • Urine output - looking for electrolyte lab readings
    • Tests include Sodium and potassium: H/A, osmolality, Urine and specific gravity
  • Interventions
    • Checking vitals every four hours to manage and maintain
    • Orthostatic blood pressure
    • Monitor through skin turgor, and promote PO inter
    • IV fluids: Hypertonic and isotonic
    • Strict I&0
    • Oral hygiene - monitor through labs
    • Cause may need to be managed or eliminated
    • Look for S/S to decrease deficit, and increase urine output

Electrolytes Replacements

• Colloids-Larger Molecules that increase blood volume, albumin, plasma, and blood
• Crystalloids-Isotonic, Hypertonic, Hypotonic

Isotonic Fluids

• Have the same salt concentration as the normal cells in the body
  • Indications -Hypotension
  • Hypovolemia
  • Hyponatremia
  • Hypercalcemia
• Complications-Fluid Overload
• Examples
  • Latated Ringers(LR)
  • 0.9% Nacl - Normal saline
  • D5W

Hypertonic Fluids:

• A solution with a higher concentration of salts vs normal cells
  • Indications- Low blood pressure, and provides calories
• Complications:
  • Fluid Volume
• Examples:
  • D5NS
  • D5LR

Hypotonic Fluids

• Solution with lower salt concentration
  • Indications-Dehydration, and Hypernatremia
• Complications:
  • Edema
• Examples:
  • 0.45% Nacl - ½ NS
  • 0.33% Nacl

FVE - Fluid Volume Excess -Hypervolemia

• Related to- Decreased output, excessive rapid intake
  • Increased oral intake intake - Renal retention and Oliguira
• Aldosterone with high levels of Gluco corticoids
• Clinical Manifestations
  • Pulmonary Edema
  • Peripheral Edema
  • HTN with tachycardia
  • Weight gain and JVD - Assessment
• Monitor past health conditions and intake.
  • Emphasis on protein. Bounding Pulses, Weight- Cough, Dyspnea, Electrolyes, and albumin.
• Strict records, and monitor cause - Evaluate if management works, and maintain the 3 D's to decrease edema

3DS-

• Diuresis
• DecreaseBP
• Dehydrate

Electrolytes

• Chemical Transactions with the ability to react
• Molecules remain uncharged and have combining power
• Cations and anions present throughout the body
• Sodium
  • (1.35-1.45)-Regulates fluids and enters via Gl
  • Transported by elimination
• Sodium Risk Factors- H20, fever and increase sodium levels

Hyponatremia

• Water is present within the Increase- Increase in Dilution or 5d - 1.35 Nect
• Treatments and restrictions are important - Fluid replacement is ½ of the NS with monitoring

Electrolye Imbalance

• Potassium-Carb Regulator
  • Potassium risk is K sparing diuretics - 3.5/5.0
  • Treatment 50% of the dextrose - K changes

Hyperkalemia

• < and over the measurement rates, with heart risks and potential renal failure causing dialysis.

8.6 to 10.2 Calcium Rates

• Important for teeth.
• Milk & veg-Increase CA, muscle weakness and heart risks

Ca

• Mag goes together Magnesium is 1.3/2.3
• Green vegetation, Nuts and Cacao - Magnesium
• < with all the different measures
• Chloride
  • 97 - 1-7mEQ - Osmotic Maintenance within the GI tract.