Cognition and Perception - Understanding of Pain, Pain Assessment, and Pain Management

Quick Medical Calculations

Problem 1: A patient needs 80 mL of Normal Saline every hour, and the giving set delivers 20 drops per mL. Calculate the drops per minute.
Problem 2: A patient is prescribed a total daily dose of 1.2 grams of an antibiotic, administered every 4 hours in equally divided doses. Calculate the amount of each 4-hourly dose.
Problem 3: Mariama is prescribed Dilantin 900mg once daily. The available preparation is Dilantin 1.5 grams in 2mL. Calculate the volume required for a 900mg dose.
Problem 4: Amy is prescribed 1000mL Normal Saline with 40mmol of Potassium Chloride (KCL) to be given over 10 hours via a volumetric pump. Calculate the mL per hour to set the pump.
Problem 5: An infant is prescribed 300 ml of normal saline over 6 hours. Using an I.V. pump what rate will you set?

Lesson Outline

Introduction to the lesson and linking it to cognition and perception concepts.
Pain and barriers to pain management.
Classification of pain and nociceptive pain pathways.
Pain management and overview quiz.

Cognition and Perception Concept

Cognition is a comprehensive term referring to all processes involved in human thought.
Perception is the interpretation of the environment.

Lesson Objectives

Develop knowledge of physiology in relation to acute pain.
Increase knowledge on the classification of types of pain.
Identify barriers that may interfere with effective pain assessment and subsequent treatment.
Gain understanding of the principles of pain assessment for successful pain management.
Use knowledge about the pathophysiology, types, and uniqueness of pain to facilitate effective pain management.

Optimal Patient Care Requirements

Nurses must acquire appropriate knowledge, skills, and attitudes towards pain.
Nurses need the ability to undertake accurate pain assessment and manage pain based on the best available evidence to prevent patients from harm.
It is unacceptable for patients to experience unmanaged pain.
Nurses must have an understanding of professional accountability in this aspect of care (Ellison, 2017).

Pain Definition

Pain is defined as “An unpleasant sensory and/or emotional experience” (ISAP, 2011).
Pain is identified as the fifth vital sign by the Australian and New Zealand College of Anaesthetists and the Chronic Pain Coalition to facilitate accountability for pain assessment and management (Kindler et al, 2015).

Unmanaged Pain Consequences

Discussion on the potential consequences of unmanaged pain on the body.

Clinical Placement Reflection

Reflect on clinical placements and instances involving pain, pain assessment, or pain management.
Evaluate whether pain was managed effectively in those instances.

Barriers to Pain Assessment and Management

Identification and discussion of barriers to effective pain assessment and management, considering patient, nurse, and organizational factors.

Pain Components

Physical: Sensation of pain via nociceptors (pain receptors) involving the Peripheral Nervous System (PNS) and Central Nervous System (CNS).
Psychological: Emotional responses to pain sensation.
Pain perception is highly subjective and influenced by various factors.

Pain Classification

Pathophysiological mechanism: Neuropathic or nociceptive.
Etiology: Malignant or non-malignant.
Duration: Acute or chronic.
Anatomic location: Head, back, etc.

Pain Classification: By Duration

Acute Pain
- Recent onset
- Transient
- Identifiable cause
Chronic Pain
- Persistent or recurrent pain (beyond the usual course of acute injury or illness)

Acute Pain

Pain is a protective mechanism.
A response to internal and external stimuli (e.g., acute appendicitis or touching a hot oven).
CIPA (Congenital insensitivity to pain with anhidrosis).

Chronic Pain

The exact mechanism involved in the pathophysiology of chronic pain is complex and remains unclear.
Hypersensitivity: Increasing numbers of pain impulses – response to stimulus that is not usually associated with pain (allodynia) – processing of pain may become independent of the original painful event.

Acute vs Chronic Pain

Feature	Acute	Chronic
BP, RR, P	Increased	No change
Nausea and Vomiting	Present	Generally absent
Visible signs of injury	May be present	Not necessarily present
End point	Has an end point	No definite end point
Medications	Regular PRN	Regular +- PRN

Pain Classification by Pathology

Nociceptive (caused by tissue damage)
- Somatic
- Visceral
Neuropathic (injury or disease of the nervous system)

Nociceptive: Somatic Pain

Characteristics:
- Aching
- Often constant
- May be dull or sharp
- Often worse with movement
- Well localized
Examples:
- Bone & soft tissue
- Chest wall

Nociceptive: Visceral Pain

Characteristics:
- Constant cramping or aching
- Poorly localised
- Referred
Examples:
- Bowel obstruction
- Ca pancreas
- Liver capsule dissention

Neuropathic Pain Descriptions

Sensations:
- Burning
- Paresthesia
- Paroxysmal
- Lancinating
- Electric like
- Raw
- Shooting
- Deep ache
Cardinal signs/symptoms:
- Allodynia: pain from a source that does not normally evoke pain.
- Hyperalgesia: exaggerated response to a normal painful stimulus.

Pain Types

Nociceptive Pain: Special nerve endings called nociceptors send pain signals to the central nervous system.
Neuropathic Pain: Caused by dysfunction in the nervous system or damage to the nerve itself.

Nociception

Pain (acute) is a physiological response that warns us of danger.
The process of nociception describes the normal processing of pain and the responses to noxious stimuli that are damaging or potentially damaging to normal tissue (Ellison, 2017).

Nociception Processes

Transduction: stimulus detected
Transmission: messages relayed
Perception: brain perceives
Modulation: messages are modified

Nociception Detailed

Transduction: Noxious stimulus converted to electrical signal.
Transmission: Electrical signal is conducted along nerve fibers to the spinal cord and brain.
Perception: Brain recognizes, defines and responds to pain.
Modulation: Brain modifies the pain signals.

Transduction

Begins when nerve endings (nociceptors) of C fibres and A-delta fibres of primary afferent neurons respond to noxious stimuli.
Nociceptors are exposed to noxious stimuli when tissue damage and inflammation occurs as a result of: trauma, surgery, inflammation, infection, and ischemia.

Transduction: Noxious Stimuli and Responses

Pain impulse is generated by an exchange of sodium and potassium ions (de-polarisation and re- polarisation) at the cell membranes.
Results in an action potential and generation of a pain impulse.

Transmission of Pain

The pain impulse is transmitted from the site of transduction along the nociceptor fibres to the dorsal horn in the spinal cord.
The C fibre and A-delta fibres terminate in the dorsal horn of the spinal cord.
The pain impulse is then transmitted via two main nociceptive ascending pathways.

Transmission: C Fibres

Primary afferent fibres
Small diameter
Unmyelinated
Slow conducting
Receptors: Respond to more than one type of noxious stimuli (Mechanical, Thermal, Chemical)

Transmission: A-delta Fibres

Primary afferent fibres
Large diameter
Myelinated
Fast conducting
Receptors: High-threshold receptors respond to stimuli over a certain intensity

Transmission: C Fibres Pain Quality

Diffuse
Dull
Burning
Aching
Referred to as slow or second pain

Transmission: A-delta Fibres Pain Quality

Well-localised
Sharp
Stinging
Pricking
Referred to as fast or first pain

Transmission Phases

Phase 1: Transmission along the peripheral nerve fibres to the spinal cord/dorsal horn.
Phase 2: Dorsal horn processing.
Phase 3: Transmission to the thalamus and cerebral cortex.

Neurotransmitters/Chemical Mediators

Mediators activate and/or sensitise the nociceptors to the noxious stimuli:

Prostaglandin: Exist and are synthesized in almost every cell of the body.
Bradykinin: An active polypeptide that forms from a blood plasma globulin and mediates the inflammatory response.
Substance P: Neuropeptide widely distributed in the CNS and PNS.
Potassium: Intracellular electrolyte facilitating action potential and the contraction of skeletal and smooth muscles including the heart.
Glutamate: Nonessential amino acid and the most abundant excitatory neurotransmitter in the CNS.
Serotonin: Neurotransmitter 5-hydroxytryptamine (5-HT) found in the central nervous system (CNS).
Histamine: Biogenic amine involved in local immune responses, acting in both the CNS and PNS.
Adenosine Triphosphate: ATP a substance present in all living cells that provides energy for many metabolic processes.

Perception of Pain

The reticular system: Responsible for the autonomic and motor response to pain and for warning the individual to do something.
Somatosensory cortex: Involved with the perception and interpretation of sensations.
Limbic system: Responsible for the emotional and behavioural responses to pain.

Modulation of Pain

The multiple pathways involved in the modulation of pain are referred to as the descending modulatory pain pathways.
These can lead to either an increase in the transmission of pain impulses (excitatory) or a decrease in transmission (inhibition).

Modulation of Pain - Descending Inhibition

Involves the release of inhibitory neurotransmitters that block or partially block the transmission of pain impulses and produce analgesia effect.
Includes:
- Endogenous opioids
- Serotonin (5-HT)
- Norepinephrine (noradrenalin)
- Gamma-aminobutyric acid (GABA)
- Neurotensin
- Acetylcholine
- Oxytocin

Pain Assessment

Involves:

Assessment of the factors that may influence a patients experience and expression of pain.
Awareness of the barriers that may affect nurses assessment and management of pain - knowledge, attitudes and beliefs about pain and the nurses experience.
Accurate documentation of pain - assessment, management and re-evaluation.
Use of pain assessment tools.

Pain Assessment – PQRSTU

P – Provocation/palliation – what makes it better or worse
Q – Quality/Quantity – burning, shooting, sharp, dull, nagging
R – Region/radiation
S – Severity
T – Timing
U – affecting you (Taylor, 2010)

Pain Assessment Continued

Use a validated tool like PQRSTU.
Different assessment for each site of pain.
Redo assessments if there are changes.
0-10 scale is the minimum requirement to monitor effectiveness.
Do not forget to document.

Pain Subjectivity

"Describing pain only in terms of its intensity is like describing music only in terms of its loudness"

Management

Remember pain is subjective.
Must use a holistic approach to pain management.
Every patient deserves adequate pain relief.
Think of comfort function goals.
Important to use medication and non medication methods.
Multimodal analgesia.
Always evaluate effectiveness.

Pain Assessment and Management When Unable to Get Self Report

Unable to self report
Unconscious
Sedated
Diagnosis such as dementia

Use a Hierarchy of Techniques:

Attempts to obtain self report
Search for potential causes of pain
Observe patient behaviours
Proxy reporting of pain behaviour and activity changes

Pain Assessment and Management of the Young

Three ways of measuring pain (best combination of all three):

Self report - what the child says ( the gold standard)
Behavioural –how the child behaves
Physiological –clinical observations
Self Report: Wong-Baker faces pain scale 3-18yo or 1 -10 scale
Behavioural: FLACC - The acronym FLACC stands for Face, Legs, Activity, Cry and Consolability
Physiological: Physiological indicators

Next Lesson

Pharmacological and Nonpharmacological Interventions for Pain Management.