This chapter will review recommendations from the 2013 Society of Critical Care Medicine and recently published research 1 ( Fig. 22.1 ).
Pain
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Greater than 50% of intensive care unit (ICU) survivors report significant pain during their ICU stay
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Common causes of pain in the ICU: acute trauma, injury or burns, postoperative pain, cancer pain, invasive procedures, and routine nursing care such as endotracheal tube suctioning, wound care, and tube insertion
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Short-term consequences of unrelieved pain: catabolic hypermetabolism, increased circulating catecholamines, impaired tissue perfusion, and decreased immune function
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Long-term consequences of unrelieved pain: chronic pain, lower health-related quality of life, neuropathic pain, and posttraumatic stress disorder
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Analgosedation: analgesia-first or analgesia-based sedation (treat with an opioid before a sedative)
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Assessment: assess pain q4–6h using either the Behavioral Pain Scale or Critical-Care Pain Observation Tool ( Tables 22.1 and 22.2 )
Table 22.1
ITEM
DESCRIPTION
SCORE
Facial expression
Relaxed
1
Party tightened (e.g., brow lowering)
2
Fully tightened (e.g., eyelid closing)
3
Grimacing
4
Upper limbs
No movement
1
Partly bent
2
Fully bent with finger flexion
3
Permanently retracted
4
Compliance with ventilation
Tolerating movement
1
Coughing but tolerating ventilation most of the time
2
Fighting ventilator
3
Unable to control ventilation
4
Table 22.2
INDICATOR
DESCRIPTION
SCORE
Facial expression
Relaxed
0
Tense
1
Grimacing
2
Body movements
Absence
0
Protection
1
Restlessness
2
Muscle tension
Relaxed
0
Tense, rigid
1
Very tense, rigid
2
Vent compliance
or
vocalization
Tolerating
0
Coughing
1
Fighting
2
Talking normally
0
Sighing, moaning
1
Crying out, sobbing
2
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Pharmacologic management ( Tables 22.3 and 22.4 )
Table 22.3
DRUG
USUAL DOSE
PD/PK (IV)
METABOLISM
COMMENTS
Fentanyl
(Sublimaze)
Start at 0.5 mcg/kg/h
Titrate by 0.25 mcg/kg/h q15min to CPOT <3 or BPS ≤5
Usual maximum: 5 mcg/kg/h
Onset: 1–2 min
Duration: 0.5–1 h
Half-life: 2–4 h
Hepatic CYP3A4 major substrate
Accumulates in hepatic failure
Prolonged half-life with infusion duration
Muscle rigidity <1%
Morphine
Start at 2 mg/h
Titrate by 2 mg/h Q15min to CPOT <3 or BPS ≤5
Usual maximum: 20 mg/h
Onset: 5–15 min
Duration: 3–5 h
Half-life: 3–4 h
Glucuronidation
Hypotension and bradycardia from histamine release
Active metabolites, morphine-3-glucuronide (45–55%) and morphine-6 glucuronide (10–15%), accumulate in renal failure
Hydromorphone (Dilaudid)
Start at 0.25 mg/h
Titrate by 0.25 mg/h q15min to CPOT <3 or BPS ≤5
Usual maximum: 2 mg/h
Onset: 5–15 min
Duration: 3–4 h
Half-life: 2–3 h
Glucuronidation
Accumulates in hepatic failure
Remifentanil (Ultiva)
LD 1.5 mcg/kg; followed by 0.5 mcg/kg/h
Titrate by 0.5 mcg/kg/h q5min to CPOT <3 or BPS ≤5
Usual maximum: 15 mcg/kg/h
Onset: 1–3 min
Duration: 3–10 min
Half-life: 10–20 min
Blood and tissue esterases
Muscle rigidity >10%
Rebound pain and withdrawal symptoms due to quick offset
Table 22.4
DRUG
USUAL DOSE
PD/PK
METABOLISM
COMMENTS
Acetaminophen (Ofirmev)
IV: 650 mg q4h–1 g q6h
Onset: 5–10 min
Half-life: 10–20 min
Glucuronidation, sulfonation
CI in severe hepatic disease
Ketorolac (Toradol)
IM/IV: 30 mg then 15–30 mg q6h up to 5 days
Onset: 10 min
Half-life: 2.4–8.6 h
Hydroxylation, conjugation/renal excretion
Use with caution in renal/hepatic dysfunction
May increase risk of ARF, bleeding, or GI ADR
Gabapentin (Neuronton)
PO: 300–600 mg/day÷2–3 doses
Onset: N/A
Half-life: 5–7 h
Renal excretion
Renally adjust
For neuropathic pain
Carbamazepine (Tegretol)
PO: 50–100 mg BID
Onset: 1–3 min
Half-life: 25–65 h then 12–17 h
Oxidation
For neuropathic pain
Caution in hepatic impairment
Strong inducer of CYP enzymes, substrate of CYP3A4
ADR: SJS, TEN, pancytopenia, SIADH
Pregabalin
PO: 75–200 mg BID
Onset: days
Half-life: 6 h
Urine (90% unchanged drug)
For neuropathic pain
Ketamine (Ketalar)
IV: 0.5 mg/kg ×1 LD then 1–2 mcg/kg/min
Onset: 30 s
Half-life:
alpha: 10–15 min
beta: 2.5 h
N-dealkylation, hydroxylation, conjugation
ADR >10%: confusion, irrational behavior, excitement, delirium, hallucinations
For postsurgical patients to reduce opioid consumption
Notes:
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Non-opioid adjunctive pain medications to be used in combination with opioids to reduce opioid use and optimize analgesia
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