Chapter 37 Pain Control in the Critically Ill Patient

Question 1

patients in critical care settings often

experience pain from

Answer 1

prolonged immobility, routine nursing
care (airway suctioning, dressing changes, and patient
mobility) and monitoring and therapeutic devices (catheters,
drains, and endotracheal tubes).

Question 2

Anxiety may stem from

Answer 2

pain, being in an unfamiliar
environment, and lack of control or even a fear of
impending death.

Question 3

Significant anxiety may lead to

Answer 3

agitation
and delirium, complicating diagnosis and interfering with
treatment leading to increased morbidity and mortality.

Question 4

Behavioral physiologic

scales use pain-related behaviors such as

Answer 4

posturing and facial expressions along with physiologic indicators
such as heart rate, blood pressure, and respiratory rate to assess pain intensity in patients who are unable to participate in unidirectional pain assessment scales.

Question 5

Undersedation may result in

Answer 5

ventilator dysynchrony, increased
oxygen requirements, self-removal of devices and
possibly post-traumatic stress disorder from a stay in the critical care unit.

Question 6

oversedation may result

in

Answer 6

prolonged tracheal intubation and mechanical ventilation,
increasing the chance of pneumonia and respiratory
deconditioning.

Question 7

Richmond Agitation Sedation Scale

Answer 7

sedation scale with scores ranging from 14, a violent dangerous patient, to –5, an
unarousable patient. A sedation score of 0 is most often
therapeutically targeted as it correlates with an alert and calm patient

Question 8

Ramsay Sedation Scale

Answer 8

the most
simplistic and allows for a numeric score from 1 to 6 based
on responsiveness of the patient

Question 9

Riker Sedation Agitation Scale

Answer 9

scores a patient’s level of sedation from 1 to 7 and is especially
adapted to warn the clinician of extremes of sedation and
agitation

Question 10

Adaptation to the Intensive Care

Environment (ATICE

Answer 10

a complex scoring system consisting
of two domains, consciousness and tolerance.9 The
consciousness domain evaluates wakefulness and comprehension
while the tolerance domain monitors agitation,
ventilator dysynchrony, and facial expressions.

Question 11

Few objective measures are available to assess sedation.

Answer 11

Vital signs such as heart rate, blood pressure, and respiratory rate are not specific or sensitive to sedation in the
critically ill.

Question 12

bispectral index (BIS)

Answer 12

aims to provide an objective measure of a patient’s sedation by
assigning a numerical value to a patient’s electroencephalogram
activity

Question 13

Patient comfort in the critical care setting is obtained with
the use of

Answer 13

both hypnotic and analgesic agents. Focusing first on providing analgesia and then on hypnosis may provide more effective sedation.

Question 14

recommended first-line therapy for the

treatment of pain.

Answer 14

Acetaminophen and nonsteroidal anti-inflammatory drugs

NSAIDs

Question 15

NSAIDs

Answer 15

nonselectively inhibit cyclooxygenase,
blocking the production of inflammatory
mediators

Question 16

limit

the use of NSAIDs in the intensive care unit.

Answer 16

clinical concerns of renal insufficiency and bleeding from

platelet dysfunction and gastrointestinal tract mucosa

Question 17

Renal insufficiency due to Keterolac

results from

Answer 17

from the decreased of production of prostacyclins

that increase renal blood flow.

Question 18

Migraine without Aura

Answer 18

At least five headache attacks
Headaches last 4–72 hr if untreated
Has at least two of the following, but not weakness: Unilateral pain, Pulsating, Intensity is moderate to severe, Aggravated by routine physical activity, Has at least one of the following:
Phonophobia, Photophobia
Nausea, Emesis

Question 19

Migraine with Aura

Answer 19

At least two headache attacks that also fulfill the characteristics of migraine without aura.
Headaches usually follow the aura but may begin with it and last 4–72 hr if untreated. Has at least one of the following reversible symptoms (lasting 4 min to 60 min), but no weakness.
Positive or negative visual symptoms such as scintillating scotomas, blind spot (scotoma), blurred vision, zig-zag lines, homonymous hemianopsia.
Positive or negative sensory symptoms such as tingling or numbness.

Question 20

Basilar Migraine

Answer 20

At least two attacks of migraine with an aura whose symptoms are reversible and localize to the brainstem or are bihemispheric, but without weakness.
Symptoms can include: Dysarthria
Dizziness or vertigo
Bilateral visual symptoms, including temporary blindness
Diplopia, Nystagmus
Ataxia, Decreased level of consciousness
Bilateral paresthesiae
Tinnitus with or without decreased hearing

Question 21

Aura without Headache

Answer 21

At least two attacks of symptoms typical of auras, but not weakness, such as visual, sensory or speech disturbances that resolve within 1 hr and are
not followed by a headache

Question 22

Hemiplegic Migraine

Answer 22

At least two attacks of migraine with a reversible aura of motor weakness that can last 1 hr to days
Also includes one of the following:
Positive or negative visual symptoms,
Positive or negative sensory symptoms,
Dysphasia or dysarthria.
Frequently accompanied by symptoms typical of basilar migraine.
If at least one first- or second-degree relative has a migrainous aura that includes motor weakness, it is familial hemiplegic migraine and is associated with a mutation in the neuronal calcium channel. If no first- or second-degree relative has a migrainous aura that includes motor weakness, it is sporadic hemiplegic migraine

Question 23

Opioids produce

analgesia mainly by stimulating

Answer 23

g- and k-receptors
located both centrally and peripherally; however, interaction
with other opioid receptors may lead to adverse
effects.

Question 24

Unwanted effects of opioids include

Answer 24

nausea, constipation,
urinary retention, pruritus, and excessive sedation
with possible respiratory depression. Severe constipation
leading to ileus has been treated with some success
using intravenous and parenteral opioid antagonists

Question 25

Respiratory depression occurs with opioids because

Answer 25

the ventilatory response to hypercapnia is decreased, while the response to hypoxia is obliterated.

Question 26

Hypotension is occasionally seen in | hypovolemic patients

Answer 26

as a decrease in sympathetic tone | occurs after treatment of pain with opioid administration

Question 27

Fentanyl

Answer 27

an opioid which has a rapid onset and short duration of action often necessitating continuous infusion therapy of 1 to 2 mg/kg/hr with 1 to 2 mg/kg initial loading doses to provide adequate pain control

Question 28

Sufentanil

Answer 28

a potent lipophilic narcotic with greater protein binding and smaller volume of distribution than fentanyl, resulting in a shorter duration of action

Question 29

Alfentanil

Answer 29

possesses a small volume of distribution secondary to protein binding and low lipid solubility, allowing for predictable duration of action.

Question 30

Hydromorphone

Answer 30

has a longer onset of action than fentanyl but also a longer duration of action, allowing for intermittent dosing at ranges of 10 to 20 mg/kg per 1-2 hr.

Question 31

Morphine

Answer 31

has a pharmacokinetic profile similar to hydromorphone but has a potent active metabolite that depends on renal excretion limiting its use in the critical care setting

Question 32

Morphine may also rarely lead to significant hypotension mediated by

Answer 32

vasodilatation | from histamine release.

Question 33

meperidine

Answer 33

generally avoided for prolonged therapy due to accumulation of its neuroexcitatory metabolite, normeperidine, which can cause seizures.

Question 34

Meperidine side effects

Answer 34

has vagolytic and histamine releasing side effects | both of which may result in tachycardia.

Question 35

Remifentanil

Answer 35

an ultra-short-acting opioid as it is metabolized by nonspecific plasma esterases, providing the most predictability of duration of action of all the opioid agents.

Question 36

Remifentanil-based sedation regimens

Answer 36

at doses of 0.01 to 0.2 mg/kg/min, have shown to produce better sedation and decrease the length of ICU stays

Question 37

Hypnotic Agents

Answer 37

providing anxiolysis, sedation, and amnesia, and decrease analgesic requirements. Benzodiazepines, propofol, and dexmedetomidine are the most commonly used hypnotic agents in the critical care setting

Question 38

Benzodiazepines

Answer 38

interact with the g-amino-butyric acid (GABA) receptor | creating an increase in intracellular chloride concentration and subsequent hyperpolarization of the cellular membrane.

Question 39

most common used benzodiazepines in the critical care setting

Answer 39

Midazolam and lorazepam

Question 40

flumazenil

Answer 40

a benzodiazepine antagonist, may cause withdrawal symptoms resulting in increased oxygen consumption and is therefore avoided in the critical care setting

Question 41

lengthy therapy of diazepam results in

Answer 41

a prolonged sedative effect as the hepatic metabolism of diazepam results in the production of an active metabolite known as desmethyldiazepam forcing diazepam to be considered a long-acting agent.

Question 42

Lorazepam is used frequently in the intensive care unit | at doses of

Answer 42

1 to 2 mg every 1 to 2 hr.

Question 43

Lorezapam

Answer 43

the least lipophilic benzodiazepine and therefore, has a slower onset of action than other benzodiazepines. This drug has a favorable metabolic profile as it relies on hepatic glucuronidation, producing an inactive metabolite that makes elimination more predictable.

Question 44

Large doses of prolonged intravenous lorazepam should be avoided

Answer 44

they have been associated with acute tubular necrosis, lactic acidosis and hyperosmolar states.

Question 45

Midazolam

Answer 45

frequently used in the preoperative and intraoperative areas at doses of 1 to 5 mg secondary to its water-soluble characteristics that allow the drug to become highly lipid soluble at physiologic pH allowing for a rapid onset

Question 46

Midazolam metabolism

Answer 46

Midazolam relies on hepatic metabolism and significant accumulation of midazolam may occur in patients with hepatic dysfunction during prolonged therapy because of its high lipophilicity and large volume of distribution.

Question 47

Midazolam active metabolite

Answer 47

alpha-hydroxymidazolam, which relies on renal excretion prolonging its duration of action in patients with renal disease

Question 48

PROPOFOL

Answer 48

also a GABA receptor agonist. Propofol is commonly used to induce general anesthesia but can be used at lower doses as a hypnotic agent, producing a degree of amnesia less than benzodiazepines

Question 49

PROPOFOL Cardiovascular Effects

Answer 49

Propofol also acts as a vasodilator and a cardiac depressant, resulting in a dose-dependent decrease in blood pressure and possibly heart rate, respectively.

Question 50

propofol a commonly used agent intensive care unit at doses

Answer 50

between 10 and 50 mg/kg/min.

Question 51

Long-term continuous infusions of propofol Adverse Effects

Answer 51

The phospholipid emulsion of propofol should be counted as a calorie source and may result in triglyceridemia and eventually pancreatitis. A rare but morbid complication of prolonged high-dose propofol therapy above 50 mg/kg/min, propofol infusion syndrome

Question 52

propofol infusion syndrome

Answer 52

results in mitochondrial injury, lactic acidosis, dysrhythmias, hyperkalemia, and rhabdomyolysis.

Question 53

Dexmedetomidine

Answer 53

a2-agonist with an affinity for the a2 receptor 7 times greater than clonidine. Activation of the post-synaptic a2A-receptor results in hypnosis, mild amnesia and significant analgesia that reduces the need for supplemental opioids

Question 54

A hypnotic effect is produced by dexmedetomidine | that resembles induction of

Answer 54

normal sleep at doses between 0.2 to 1.0 mcg/kg/min. The hypnotic effect of dexmedetomidine is unique, in that patients, when left undisturbed, will sleep; but when aroused with gentle stimulation, patients will be cooperative and follow commands. This effect is mediated by activation of the a2A-receptor in the locus ceruleus

Question 55

major advantages of dexmedetomidine

Answer 55

produces virtually no respiratory depression while providing sedation and reducing analgesic opioid requirements. It has been shown to facilitate extubation in patients who have previously failed extubation attempts due to severe agitation

Question 56

adverse effects of dexmedetomidine

Answer 56

enhancement of vagal effects by creating a pharmacologic sympathectomy resulting in hypotension and bradycardia. However, if therapy is initiated rapidly at a high dose, a transient hypertension and tachycardia may occur. This is then followed by hypotension and bradycardia mediated by the a2A-receptor inhibiting sympathetic tone in the peripheral vascular system.

Question 57

Dementia

Answer 57

a progressive disease with a decline in memory and cognitive skills and rarely presents acutely

Question 58

Delirium

Answer 58

an acute reversible change in mental status. It is characterized by fluctuating levels of arousal associated with sleep–wake cycle disruption brought on by the reversal of day–night cycles and is associated with worse outcomes and increased long-term mortality

Question 59

Hyperactive delirium

Answer 59

easily recognized as patients are agitated and combative interfering with therapeutic measures;

Question 60

Hypoactive delirium

Answer 60

characterized by calm appearance, decreased mobility and inattention, is actually associated with a worse prognosis

Question 61

In a critically ill patient with an acute change or fluctuating mental status, the CAM-ICU (Confusion Assessment Method for the ICU) aims to

Answer 61

evaluate inattention, altered level of | consciousness, and disorganized thinking.

Question 62

In order to be | diagnosed with delirium, a patient must

Answer 62

not be heavily sedated and demonstrate inattention along with either altered level of consciousness or disorganized thinking

Question 63

associated with the development of delirium

Answer 63

disruption of the sleep cycle

Question 64

Haloperidol

Answer 64

haloperidol 0.5 to 5 mg every 5 min until agitation is controlled. Haloperidol antagonizes dopamine-mediated neurotransmission, stabilizing cerebral function.

Question 65

Haloperidol Adverse Effects

Answer 65

extrapyramidal symptoms, neuroleptic malignant syndrome, hypotension, and QT prolongation is recommended specifically as QT prolongation can lead to torsades de pointes.

Question 66

Olanzapine

Answer 66

newer agent for the treatment of delirium, has similar efficacy to haloperidol but with fewer extrapyramidal side effects at doses of 2.5 to 5 mg daily

Question 67

One of the most common reasons to utilize neuromuscular | blocking agents in the intensive care is

Answer 67

patient–ventilator dyssynchrony. Such dyssynchrony can result in increased airway pressures which may predispose the patient to ventilator induced lung injury. neuromuscular blocking agents are also used to decrease oxygen consumption in patients with tenuous oxygen supply versus demand

Question 68

The greatest concern to neuromuscular blockade use is

Answer 68

prolonged paralysis, particularly in patients receiving steroid therapy.

Question 69

The most commonly used neuromuscular blocking | agent in the critical care unit is

Answer 69

cisatracurium at infusion rates of 1 to 5 mg/kg/min as it undergoes Hoffman degradation. Only temperature and pH alter the pharmacokinetics; therefore patients with renal and hepatic dysfunction can be treated with cisatracurium with minimal concern for prolongationof action.