ACUTE PAIN AND THE TRAUMA PATIENTMultimodal Approach to treating
acute pain in trauma patients
Introduction
1. Discussion of the pathophysiology of acute pain.
2. Discuss opiates and adjuvant medicines.
3. Outline acute pain management in patients on chronic pain regimens, including withdrawal avoidance.
4. Discuss relevant regional anesthesia techniques.
What is acute pain?
Caused by noxious stimulation secondary to Injury Disease Abnormal function
Pain is nociceptive vs neuropathic
Pain signals carried by A-delta and C fibers
Nociceptors
Mostly Free Nerve Endings
High thresholds for activation
Intensity of stimulation is proportional to rate of discharge
Four physiologic processes involved in Nociceptive Pain
Transduction
Transmission
Modulation
Perception
Anatomy of Pain Pathways
Three Neuron pathway to get signal from periphery to brain First Order Neurons
Cell Bodies live in dorsal root ganglia Nerve endings connecting to dorsal horn of spine May also synapse with interneurons, sympathetic
fibers and motor neurons
Pain Pathways cont
Pain Pathways cont
Second Order Neurons Synapse with First Order Neurons in dorsal
horn of spine Cross the midline and connect to thalamus Opiates work here Many interneurons interact
Pain Pathways cont
Pain Pathways cont
Third Order Neurons Connect thalamus to postcentral gyrus of
cerebral cortex and others Interneural connections
Pain Perception Emotional Response Feedback (efferent fibers)
Pain Pathways cont
Modulation of Pain
Occurs at: Nociceptors In the spinal cord Supraspinal structures
These can either suppress or facilitate pain
Modulation at Nociceptors
Can become sensitized Increased frequency of response Decreased threshold to stimulation Decreased response latency
Leads to increased Prostiglandin production, producing hyperalgesia
NSAIDS, ASA, steroids work here
Modulation in the Spinal Cord
Function of complex interneuron interaction
“Substance P” increases histamine and serotonin, and other neuroexcititory peptides
Capsaicin and local anesthetics can work here
Modulation in Supraspinal Structures
Facilitators Produce “wind up” via Wide Dynamic Receptors Receptor field expansion Hyperexcitability
Inhibitors Gate Theory from different segments confined
via WDRsGABA drugs work here Supraspinal Descending Pathways
Interact with first and second order neurons at alpha2, opiate, and serotonergic receptors
TCAs work here
Systemic Responses to Pain
Moderate to Severe Pain effects multiple organ systems
Significant influence of Morbidity and Mortality
Mediated via increased sympathetic tone and hypothalamus mediated reflexes
Systemic responses to pain
Cardiovascular Increased HTN, PVR Tachycardia Myocardial irritability Increased oxygen demand Increased CO in normal heart, decreased in
diseased
Leads to MI and dysrhythmia
Systemic responses to pain
Respiratory Increased CO2 production
Increased minute ventilation Increased work of breathingEspecially problematic with lung disease
Decreased chest movement (Splinting) Decreased tidal volume and FRCAtelectasis, intrapleural shunting, hypoxemia
Decreased coughDecreased secretion clearance
Systemic responses to pain
GI Increased sympathetic tone
Decreased intestinal motility Decreased urinary motilityIleus and urinary Retention
Increased Gastric acid productionRisk of aspiration
Gastric distentionFurther decreased FRC
Systemic responses to pain
Endocrine Increased catabolic response
Increased catecholamines, cortisol, glucagon Decreased anabolic hormone
Decreased insulin and testosterone Hematologic
Increased platelet adhesion Decreased fibrinolysis
Hypercoagulability, DVT, PE
Systemic responses to pain
Immune Leukocytosis LymphopeniaInfection and poor wound healing
PsychologicalAnxiety, poor sleep, depression
Opiates and Adjuvant medicines
Opiates have become more commonly used to treat chronic, non-malignant pain
“Normal” doses ineffective Therapeutic dose can vary by 1000% Multimodal approach becomes more useful
Opiates
Mechanism of action Work at mu, kappa, delta, sigma receptors in
spine and supraspinal structures Mu receptors in dorsal horn provide bulk of
analgesia Receptors in medulla produce N/V Supratentorial receptors involved in reward/dug
seeking Inhibit presynaptic release of, and postsynaptic
response to excitatory neurotransmitters in nociceptors Ach sP
Physiologic effects of Opioids
Cardiovascular No significant impairment Bradycardia, vagal mediated Decreased sympathetic flow Histamine release
Respiratory Depress ventilation CO2 respiratory drive blunting (brainstem) Bronchospasm (histamine) Chest wall rigidity
Physiologic effects of Opioids
Cerebral Reduction in cerebral oxygen consumption No change in EEG, no amnesia
GI Decreased peristalsis Sphincter of Oddi contraction
Endocrine Blunt stress response hormones
Goal of Safe Opioid use
Use for mod to severe pain when other agents are ineffective
Monitoring for potential side effects is crucial
Goal is adequate pain control with minimal side effects Typical starting dose for MS is 0.1mg/kg,
increase by 0.05mg/kg Dosing varies significantly; 10X
Goal of Safe Opioid use
Biggest risk of opioids is Resp Depression May or may not be dose dependent Patient may or may not be tolerant
(controversial)
High risk patients: Elderly OSA
Opiod Pearls
Produce state where injury isn’t bothersome Dose varies Decreases spontaneous ventilation and
response to hypercarbia PCA produces less addiction than RN
controlled prn dosing Need liver failure >80% for accumulation of
drug Renal impairment increases plasma
concentrations of active metabolites (MS, demerol; not fentanyl)
Opioid Problems
Ongoing use activates glial cells Release neuroexcititory signals Release pro inflammatory signals
Oppose analgesia Enhance tolerance Enhance Resp depression Enhance dependence Promote development of (and maintanace)
pathologic pain pathways Via non-opiod receptors
Adjuvant Rx
Anticonvulsants Action is to suppress spontaneous neural discharge
in damaged/overactive neurons Especially useful in neuropathic pain, acute and
chronic Slow onset Long half-life Side effects (Gabapentin)
Sleepiness/dizziness Allergic reactions Withdrawal precipitated seizure Suicidal thoughts Pregnancy Class C
Adjuvant Rx
Antidepressants Action is to block presynaptic reuptake of
serotonin and/or norepi Potentiates benefits of opioids Help normalize sleep Side effects
Antimuscarinic (dry mouth, urinary retention) Antihistamine (sedation, increased gastric pH) Alfa-adrenergic blockade (orthostatic
hypotension) Suicidal thoughts
Adjuvant Rx
COX inhibitors (NSAIDS, ASA, Tylenol) Action is prostaglandin inhibition Benefits
Analgesia Antipyretic Anti-inflammatory Enhances opioid effects
Side Effects GI upset/ulcers Platelet inhibition Bronchospasm (potential) Renal dysfunction
Adjuvant Rx
COX-2 selective inhibitors (Celebrex) No platelet inhibition Decreased upper GI side effects 12-24 hr duration Analgesia equal in non-selective COX
inhibitors
Acute pain management in patients on chronic pain regimens
Key is identifying chronic pain regimen Home medicine history (dosing, frequency,
duration) Family assistance Tox screen
Social history
Acute pain management in patients on chronic pain regimens
HOME MEDS
Acute pain management
Goal is adequate therapy with minimal side effects
PCA advantages Cost effective Safe (when used correctly) Superior analgesia High patient satisfaction
Acute pain management
PCA cont Basal rate
Controversial May avoid breakthrough May increase Resp Depression 30-50% of total dose may be via BR
Useful for adding in home dose
Acute pain management
Physical dependence Occurs in all patients on large doses of opioids
for prolonged periods Dependence does not equal addiction
Acute pain management
Avoiding withdrawal: alpha2 agonists (Clonidine) Acts postsynaptically to decrease
norepi/sympathetic outflow presynaptically Decreased SVR/BP Negative Chronotrope Analgesia Sedation Anxiolysis Prolonged duration of peripheral nerve blocks
Available PO, transdermal, parenteral
Acute pain management
Clonidine side effects Bradycardia Hypotension Sedation Dry mouth
Acute pain/trauma and regional anesthesia techniques
Advantages of regional anesthesia Better pain control Better preserved pulmonary function Early ambulation Early PT Decreased M&M
Risks: Local anesthetic toxicity Damage to nerve/other structures
PERCUTANEOUS CONTINUOUS NERVE BLOCK FOR TREATMENT OF PAIN IN
CHEST WALL TRAUMA
Background
Trauma is a leading cause of death and disability
Thoracic trauma accounts for 10 to 15% of trauma admissions
25% of annual traumatic deaths result from chest trauma
Rib fractures are the most common injury associated with chest trauma.
Trauma associated with rib fractures results in significant morbidity and mortality
The Morbidity and Mortality of Rib Fractures
7147 trauma patients reviewed Level 1 Trauma Center
10% had rib fractures
Only 6% of patients had isolated rib fractures, 94% had associated injuries 32% had HTX/PTX 26% had Lung Contusion
Ziegler, D.. The morbidity and mortality of Rib Fractures.The Journal of Trauma, 1994.
Conclude that rib fractures are a marker of severe injury Mortality rate of 12%, with most deaths (69%)
occurring within first 24 hours 55% patients required immediate operation or ICU
admission 35% patients required ECF upon discharge 35% developed pulmonary complications, 6% of
these patients died A lower ISS in elderly that died compared to
younger patients, suggests it takes a lesser injury to be lethal in elderly
Increased severity of injury and mortality with increasing number of rib fracturesZiegler, D.. The morbidity and mortality of Rib Fractures.The Journal of
Trauma, 1994.
Perils of rib fractures
Retrospective analysis at Level 1 trauma center
Identified High-Risk rib fractures to be those associated with intrathoracic injury, increased morbidity and mortality
Factors indicating a high-risk rib fracture include High energy trauma Extremes of age > 3 rib fractures Associated injuries
Perils of rib fractures. Sharma OP, Oswanski MF, Jolly S, Lauer SK, Dressel R, Stombaugh HA American Surgeon, 2008
Elderly Trauma Patients with Rib Fractures Are at Greater Risk of Death and Pneumonia
The population 65 years of age and older currently represents approximately 12% of the population in the United States
The most common mechanism for rib fractures are motor vehicle crashes
Low velocity falls increase with increasing age Trauma patients older than 65 are more likely
to die or have significant complications after chest trauma than similarly injured younger patients Bergeron, E et al. Elderly Trauma Patients with Rib Fractures Are at greater risk
of Death and Pneumonia. J of Trauma. 54:3, 478-484. March 2003.
Elderly Trauma Patients with Rib Fractures Are at Greater Risk of Death and Pneumonia
Also found that severity of trauma morbidity and mortality increase with increasing number of rib fractures
Background
The pain associated with rib fractures leads to: respiratory compromise impairment of pulmonary mechanics
including: hypoventilation atelectasis decreased pulmonary compliance poor pulmonary drainage hypoxia
This can be further complicated by pre-existing lung disease, underlying pulmonary contusion and development of pneumonia
Background
Flail Chest 70% long term dyspnea 49% had persistent chest wall pain
Landercasper JL, Cogbill TH, Lindesmith LA: Long-term Disability after Flail Chest Injury.J trauma. 24:410-14, 1984
Paradoxical chest movement
Goals of Treatment
1. Pain Control
2. Pulmonary Toilet
3. Management of
associated Injuries
Methods of pain control
Pain management is critical in these patients
Despite multiple approaches to pain control
including: anti-inflammatory medications systemic narcotics intrapleural blocks intercostal nerve blocks epidurals
There is no single method satisfactory to all patients.
Think MULTIMODAL
Medline search 1966-2002 Summarized the various analgesic
techniques used in patients with multiple fractured ribs
No single method that can be safely and effectively used for analgesia in all circumstances.
Acute Pain Management of Patients with Multiple Fractured Ribs
Karmakar, M, et al. 54:3. 615-625. March 2003
Opioids/Narcotics
PROS Systemic opioids
are readily available and are minimally invasive.
CONS Respiratory
Depression Sedation Constipation Hypotension Nausea/Vomiting Urticaria/Pruritus
Epidural Catheter
PROS May be the gold
standard for analgesia in rib fractures allowing treatment of multiple levels as well as bilateral fractures.
No CNS depression Prolonger duration
CONS Hypotension Urinary Retention Altered Neuro exam Avoid anticoagulation Risk of
Infection Epidural hematoma Spinal cord injury (rare)
Intercostal Nerve Block
PROS Highly effective
for 8-24 hours No CNS
depression
CONS Require multiple
injections at multiple levels
Risk of Pneumothorax Risk of toxicity Risk of vascular
puncture and injection
Short duration
Intercostal Nerve Block
ON-Q
PROS Effective for
multiple rib fractures, bilateral
No CNS depression
No altered neuro exam
Can be discharged home/rehab
Anticoagulation OK
CONS Risks of systemic
toxicity with local Pneumothorax Hematoma
CATHETERS
Trauma-Rib Fx
Trauma-Rib Fx
Trauma-Rib Fx
What’s important
Good prep of the area Pain score not revealing in multiple trauma
patients Incentive spirometry-focus specifically on
the pain associated with deep breathing reduce the incidence of pneumonia often seen
in multi-level rib fracture patients
Clinical Experience Reviewed patients who received an ON-Q
Catheter system from July 2005-Feb 2008 41 trauma patients with ON-Q placement
identified Age range 18-88 years
average age 61 years old Mean # rib fx 7.61 VAS pre insertion 9.4 VAS post insertion 4.8
p<0.001
Halm, Shapira Presented ACS Annual Meeting 2008
Summary
In the absence of a universal modality for the management of pain associated with rib fractures, the “over the ribs” ON-Q catheter pain system provides a safe and effective method for pain relief in the injured patient with rib fractures.
It enables minimization of opiates utilization, early ambulation and effective pulmonary toilet.
Patients can continue treatment after discharge from hospital.
The placement is a simple bedside technique and does not require a specialized practitioner for placement.
Associated TraumaSternal fracture
Bilateral parasternal insertion
Other Opportunity
FEMUR FRACTURE
PUMP INSERTION IN FEMUR-deep
PUMP INSERTION IN FEMUR-superficial
ACETABULUM FRACTURE
ACETABULUM FRACTURE
Fascia Iliaca Block
Goal: Block the femoral and lateral femoral cutaneous nerves, ideally with proximal spread into the lumbosacral plexus
Technique: Ultra sound guidance Medial to ASIC and sartorius muscle, lateral to
fascia over psoas and femoral nerve/artery Just deep to fascia iliaca 30-40mL dilute local anes (0.2% ropivacaine) Single shot vs catheter infusion
Conclusion Pathophysiology of pain
Complex interneural interactions Opioids
Mainstay of Rx PCA safe and effective
Adjuvant meds Improve pain control Help avoid opioid side effects
Acute on chronic pain Requires multimodal approach
Regional Anesthetic techniques Improve outcomes and patient satisfaction
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