Test 4: PACU (pt. 2/3) CV, Delirium, Pain Flashcards
What is the definition of hypotension?
Compromise should be indicated by the clinical signs of hypoperfusion, rather than numerical numbers.
Classically, it has been defined as a fall in arterial blood pressure (BP) of more than 20% below baseline, or an absolute value of systolic BP (SBP) below 90 mm Hg, or of mean arterial pressure (MAP) below 60 mm Hg.
What is the MOST COMMON cause of hypotension in the PACU?
Hypovolemia !!! secondary to inadequate replacement of intraoperative fluid and blood loss (decreased preload).
May be due to:
-Volume depletion r/t inadequate fluid replacement during surgery
-Blood loss during surgery
-Ongoing postop blood loss
What are the clinical signs of hypoperfusion?
-Altered mental status
-Hypotension, tachycardia and tachypnea
-Decreased capillary refill, peripheral cyanosis, cool/clammy skin, and mottling
-Oliguria
What is the treatment for hypotension in PACU?
Initial treatment should focus on restoring circulating volume.
-Assess for active bleeding
-300 to 500 mL fluid bolus of saline or LR
-If no response is noted, r/out myocardial dysfunction as the cause
What is the differential diagnosis for Hypotension?
-Hypovolemia (most common)
-MI, tamponade, PE
-Dysrhythmias
-Tension PTX
-Anaphylaxis/Histamine release (Anesthetic agents)
-Vasodilators (if overly sensitive response)
-Sepsis
How do you define Hypertension?
Hypertension is defined as a rise in arterial BP of more than 20% above baseline or an absolute value of arterial BP above age-corrected limits.
What are some causes of Hypertension?
-SNS Stimulation
-Pain
-Respiratory compromise
-Visceral distention
-Inc in plasma catecholamines that produce vasoconstriction
What is the leading cause of hypertension and tachycardia in the PACU?
Pain
How does pain cause hypertension?
Pain results in stimulation of the somatic afferent nerves, producing a pressor response known as the somatosympathetic reflex.
When should planning for postop pain control start?
In the holding room (pre-op) where you must set realistic goals, manage expectations (be honest - it will hurt), and continue current pain medications whenever possible.
What are some agents you can use in a multimodal approach?
-Acetaminophen and NSAIDs
-Ketamine
-Alpha agonists
-Gabapentinoids
-Regional anesthesia / local anesthetics
-Corticosteroids (anti-inflammatory and helps with N/V)
-Opioids
-Repositioning and reassurance (Hand holding/it will be ok)
What is the differential diagnosis for hypertension?
-Pain
-Hypoxemia/hypercarbia (stimulation of the vasomotor area of the medulla, leading to inc vasomotor tone)
-Distention of the bladder, bowel, or stomach (stimulation of afferent SNS)
-Hypothermia/Shivering (inc catecholamines)
-Pre-existing HTN (30% of patients, continue BB throughout periop period)
-Medications (Vasopressors, Withdrawal from opioids, Narcan administration, Ketamine, and rebound effects of clonidine and/or beta blockers)
T/F: Dysrhythmias seen in the PACU are often transient and most commonly have an identifiable cause that is not an actual myocardial injury.
True
What are the major postanesthetic and surgical factors that lead to a relatively high incidence of perioperative dysrhythmias?
-Hypokalemia (r/t hyperventilation, respiratory alkalosis, gastric suctioning, diuretic use
-Fluid overload
-Anemia (impaired O2 transport)
-Hypoventilation with hypercarbia (hypoxia leads to myocardial ischemia and cardiac irritability. Hypercarbia stimulates the SNS)
-Altered acid-base balance
-Substance withdrawal
-Circulatory instability (hypotension)
Incomplete reversal of neuromuscular relaxation can lead to postoperative pulmonary complications including ?
-compromised cough
-obstruction
-airway patency
-hypoventilation
Why should objective monitoring measures (e.g., train-of-four ratio > 0.90 and double burst stimulation) be performed regularly in the early postanesthesia phase?
-Patients who received a reversal agent often exhibit signs of residual neuromuscular blockade in the PACU, particularly the elderly.
-Should be performed to determine depth of residual blockade and prevent pulmonary complications
What are the objective monitoring measures used to assess NMB?
-TOF > 0.90
-Double burst stimulation
How can you decrease the incidence of residual paralysis?
-Use of short-acting relaxants
-Reversal agents
What is the main advantage of Sugammadex?
The main advantage of sugammadex is reversal of neuromuscular blockade without relying on inhibition of acetylcholinesterase and earlier spontaneous postoperative ventilation.
-Specifically designed to reverse rocuronium.
Which is more dangerous: Marginal reversal or near-total paralysis?
Marginal Reversal is more dangerous
Why is Marginal reversal more dangerous than near-total paralysis?
-an agitated patient exhibiting uncoordinated movements and airway obstruction is more easily identified.
-A somnolent patient exhibiting mild stridor and shallow ventilation from marginal neuromuscular function might be overlooked.
-Insidious hypoventilation leading to respiratory acidemia or regurgitation with aspiration can occur later into recovery.
What medications potentiate NMB?
-Aminoglycosides
-Lasix
-Inderal
-Dilantin
What underlying neuromuscular diseases exhibit exaggerated or prolonged responses to muscle relaxants?
-Myasthenia gravis
-Eaton-Lambert syndrome
-muscular dystrophies
Such patients can exhibit postoperative respiratory insufficiency from inadequate neuromuscular reserves.
Periodic mental and behavioral status assessments are recommended during what times?
Postoperative mental status changes may be associated with poor anesthetic outcomes; therefore, periodic mental and behavioral status assessments are recommended from the time of emergence and throughout the early postanesthesia recovery period.
What is Delirium?
A condition characterized by extreme disturbances of arousal, attention, orientation, perception, intellectual function, and affect.
-It is most commonly accompanied by fear and agitation.
Which procedure has the highest incidence of postop delirium?
62% after operative hip procedures (geriatric).
What are the causes of postoperative delirium?
-Withdrawal psychosis
-Toxic psychosis (exposure to toxins)
-Circulatory and respiratory origin (hypoxemia, hypercarbia, and hypotension)
-Functional psychosis (brief rxn of paranoia and other changes not caused by an organic abnormality)
How can withdrawal psychosis cause emergence delirium?
Withdrawal of various substances such as alcohol and illicit drugs.
What drugs contribute to Postop Delirium?
Premedications, including anticholinergics, benzodiazepines, and opioids, may induce untoward reactions.
-Anticholinergics, specifically atropine and scopolamine, have been noted to cause central anticholinergic syndrome. These drugs cross the blood-brain barrier, altering the neurotransmitter balance and causing agitation, combativeness, and lack of cooperation.
-Benzodiazepines may contribute to postoperative delirium, especially in the elderly.
What are the most frequently occurring neurologic phenomena in older adults?
Postoperative Delirium (POD) and postoperative cognitive dysfunction (POCD)
How do you define POD?
A disruption of perception, thinking, memory, psychomotor behavior, sleep-wake cycle, consciousness, and attention.
POD is associated with an increased risk for what negative things?
-Periop mortality
-Institutionalization
-Dementia
What are the risk factors for POD?
-Age > 65 (same as POCD)
-renal insufficiency and metabolic derangements
-Poorly controlled pain: multimodal management
-Polypharmacy (pyschoactive drugs)
-Functional impairment (frailty)
-Urinary retention and presence of a urinary catheter
What drugs are associated with the development of delirium and should be avoided during the perioperative period, especially in geriatric population?
benzodiazepines, anticholinergics, and antihistamines
What is the treatment for POD?
1) R/out Hypoxemia first!!!
2) Treat potential causes (anxiety, pain, residual anesthesia, etc)
Goal is to maintain patient safety!!
How do you define delayed awakening?
A clinician’s expectation in a specific circumstance that the patient “should be awake by now” but is not.
What is the MOST COMMON cause of delayed awakening?
Prolonged action of anesthetic medications.
What are other causes of delayed awakening?
-Metabolic causes: hypoglycemia, hyperglycemia, electrolyte disturbances, and hypothyroidism
-Neurologic injury: rare cause of delayed awakening of the nonneurosurgical patient. Potential causes include: CVA, intracranial hemorrhage, increased ICP, uncontrolled extreme hypertension or hypotension, and emboli.
Prolonged action of anesthetic drugs is the most common cause of delayed awakening!!!
What causes Serotonin Syndrome?
The concurrent administration of two or more serotonergic medications (Antidepressants and chronic pain).
What are the S/Sx of Serotonin Syndrome?
Mild: mydriasis, diaphoresis, myoclonus, tachycardia, anxiety, restlessness
Severe: fever, mental status changes, muscle rigidity, multiple organ failure
What is the most important measure of Pain?
Patient self-report !!
What are ways to assess pain?
-Verbal rating or visual analog scale
-patient’s exposure to painful procedure
-behavioral signs, such as crying or agitation
-a proxy pain rating by someone who knows the patient well
-physiologic indicators, such as elevated vital signs, and genetic factors can interfere with pain perception and the effectiveness of medications used to treat pain.
-Genetic factors interfere with pain perception and medication effectiveness.
What is the definition of Pain?
Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage.
What are the four processes of Nociceptive Pain?
Transduction
Transmission
Perception
Modulation
What is Transduction?
The transformation of a noxious stimulus into an action potential.
What is Transmission?
The process by which an action potential is conducted from the periphery to the CNS.
What is Perception?
Occurs once the signal is recognized by various areas of the brain.
-Amygdala, somatosensory areas of the cortex, the hypothalamus, and the anterior cingulate cortex
What is Modulation?
Altering neural afferent activity along the pain pathway; it can suppress or enhance pain signals.
What are Nociceptors?
Pain receptors. Free nerve endings.
-Conduct noxious stimuli to the dorsal horn of the spinal cord
-Categorized according to morphology (diameter, myelination, and conduction velocity).
Generally, the larger the diameter, the faster the conduction velocity
Which fibers have the fastest conduction velocity?
A Alpha Fibers (Largest Diameters)
Which fibers have the slowest conduction velocity?
C Fibers (Smallest Diameter)
What do the myelinated, A-Delta neurons do?
-Conduct APs at velocities between 6 and 30 m/s
-Elicit fast-sharp pain
-They are responsible for the initial mechanical or thermal pain that is felt and alert an individual of tissue damage, thereby resulting in the reflex withdraw mechanism.
What do the unmyelinated C Fibers do?
-Slower velocities, between 0.5 and 2 m/s
-Known as Polymodal fibers (respond to mechanical, thermal, and chemical injuries)
-Delayed, slow, second pain
-“dull,” “burning,” “throbbing,” and “aching.”
What do the A Beta Fibers do?
-Large, myelinated
-Touch, pressure, and proprioception
What occurs when peripheral tissues (skin, bone, and viscera) receive chemical, thermal, or mechanical stimuli or are traumatized by either surgery or injury?
-Release of chemical mediators from the inflammatory response
-Release of NTs from nociceptive nerve endings
What is Transmission?
The process by which an action potential is conducted from the periphery to the CNS.
-There are multiple pathways that carry noxious stimuli to the brain. Spinothalamic tract is the most important.
Describe how action potentials are generated.
Chemical mediators and neurotransmitters stimulate the peripheral nociceptors, causing an influx of sodium ions to enter the nerve fiber membranes (depolarization), and a subsequent efflux of potassium ions (repolarization). An action potential results, and a pain impulse is generated.
Which pathway is the most important that carries noxious stimuli to the brain?
Spinothalamic.
-Nociceptive fibers traveling from the spinal cord to the thalamus.
What makes up the Spinothalamic (Anterolateral) System?
-Carries signals from the periphery (trunk and lower extremities)
-Uses A Delta and C Fibers
-Cell bodies are located in the dorsal root ganglia of the spinal cord
-Ascend/Descend using Tract of Lissauer
-Synapse with 2nd order neurons in the gray matter of the dorsal horn (A Delta with Laminae I and V, C with Laminae II)
-2nd order neurons cross the midline, and ascend via the anterolateral pathway to the thalamus
-In the Lateral Thalamus, 2nd order neurons synapse with 3rd order neurons, which then project to the Cerebral Cortex
Where does the Spinothalamic System carry signals from?
The periphery - trunk and lower extremities.
What are the primary afferent neurons in the Spinothalamic System? Where are their cell bodies located?
A Delta and C Fibers
Cell bodies are located in the dorsal root ganglia of the spinal cord.
Upon entering the spinal cord, how do the A Delta/C Fibers ascend/descend?
Via the Tract of Lissauer
Where do the primary afferent neurons go after leaving the Tract of Lissauer?
They enter the gray matter of the dorsal horn, where they synapse with 2nd order neurons and terminate in the Rexed Laminae (I,II, and V)
Which Laminae do the A Delta fibers synapse with? The C Fibers?
A Delta - Laminae I and V
C Fibers - Laminae II
Where do the 2nd order neurons go after synapsing with the 1st order neurons?
-Cross the midline of the spinal cord through the anterior commissure
-Ascend in the anterolateral pathway of the spinothalamic tract to the Thalamus
What happens when the 2nd order neurons get to the Lateral Thalamus?
They synapse with 3rd order neurons, which then project to the cerebral cortex.
What is perception of pain?
Occurs once the signal is recognized by various areas of the brain, including the amygdala, somatosensory areas of the cortex, the hypothalamus, and the anterior cingulate cortex.
What is Modulation of pain?
Modulation of pain transmission involves altering neural afferent activity along the pain pathway; it can suppress or enhance pain signals.
How does suppression of pain occur?
Via local inhibitor interneurons (brainstem) and descending efferent pathways (spinal cord dorsal horn).
-Also have inhibitory receptors and NTs: Endogenous opioids (enkephalin/dynorphin), glycine, GABA, Norepi, Serotonin, Ach.
What is the only pre-emptive treatment that improved all patient outcomes (pain intensity scores, supplemental analgesic consumption, and time to first analgesic consumption?
Epidural Anesthesia
Review Slide 49
Yes
What is Multimodal Anesthesia?
-Agents with different mechanisms of analgesia may have synergistic or additive effects
-Captures the effectiveness of individual agents at optimal dosages to maximize efficacy while minimizing side effects
What is Preventative Analgesia?
To suppress central sensitization, analgesia should be maintained throughout the perioperative period.
-Formerly known as pre-emptive analgesia
What are the preventative and multimodal analgesia medications?
-Opioids
-Non-opioid analgesics (NSAIDS, Acetaminophen)
-NMDA antagonists (Ketamine)
-Alpha 2 agonists (Clonidine, Dexmedetomidine)
-Local anesthetics (Infiltration, PNB, Epidural/SAB, infusion)
-Magnesium infusion
-Anticonvulsants / Membrane stabilizers (Gabapentinoids)
-Glucocorticoids
What is an excellent resource for evidence-based guidelines in the field of pain management?
The procedure-specific guidelines offered via a web-based program called PROSPECT (Procedure-Specific Postoperative Pain Management).
What is the definition of Acute Pain?
-Noxious stimulation from traumatic injury (chemical, thermal, or mechanical), surgery, or acute illness.
-Usually diminishes over the course of healing
-Effected by social, cultural, and personality factors
-Tx cause
-If poorly controlled, can lead to chronic pain
What are the CV consequences of pain?
Increased HR/BP/myocardial work
What are the pulmonary consequences of pain?
Decreased VC/TV/TLC
What are the GI consequences of pain?
Decreased gastric emptying/intestinal motility
What are the GU consequences of pain?
Increased urinary sphincter tone
What are the coagulation consequences of pain?
Increased platelet aggregation, venostasis
What are the immunologic consequences of pain?
Decreased immune function
What are the psychologic consequences of pain?
Fear, anxiety, hopelessness, anger
What are the other adverse consequences of pain?
-Contribute to increased patient morbidity and mortality (Poorly controlled acute pain may lead to chronic pain states)
-Prolonged hospital stay and patient recovery
-Negative impact surgical/hospital experience and reduced patient satisfaction
-Overall increased healthcare costs
