Analgesics & Sedatives

The Richmond Agitation–Sedation Scale

Score	Term	Description
+4	Combative	Overtly combative or violent; immediate danger to staff
+3	Very agitated	Pulls on or removes tube(s) or catheter(s) or has aggressive behavior toward staff
+2	Agitated	Frequent nonpurposeful movement or patient–ventilator dyssynchrony
+1	Restless	Anxious or apprehensive but movements not aggressive or vigorous
0	Alert and calm	Spontaneously pays attention to caregiver
-1	Drowsy	Not fully alert, but has sustained (more than 10 seconds) awakening, with eye contact, to voice
-2	Light sedation	Briefly (less than 10 seconds) awakens with eye contact to voice
-3	Moderate sedation	Any movement (but no eye contact) to voice
-4	Deep sedation	No response to voice, but any movement to physical stimulation
-5	Unarousable	No response to voice or physical stimulation

 

Effects of sedative drugs

Drug	Anxiolysis	Hypnosis	Amnesia	Analgesia
Benzodiazepines	+	+	+	–
Dexmedetomidine	+	–	–	+
Haloperidol	+	+*	+*	–
Opioid analgesics	–	–	–	+
Propofol	+¶	+	+*	–

 

Benzodiazepine과 barbiturate의 차이: 둘다 GABA receptor에 작용하나 Benzodiazepine은 특정 농도 이상 도달하면 (GABA dependant) 더이상 효과가 없지만 barbiturate는 농도가 올라갈수록 sedation이 깊어진다. Barbiturate coma therapy는 있어도 benzodiazepine coma therapy는 없다.

 

Remifentanyl은 오래 주입하다가도 끊으면 바로 깸. fentanyl, thiopental, pentobarbital은 주입하는 시간이 길면 깨는데도 오래 걸림.

 

Table 1. Systemic and cerebral physiologic effects of sedatives and analgesics

	HR	CO	SVR	MAP	ICP	CPP	CBF	CMRO2
Benzodiazepines	↔/↑	↓/↔	↓/↔	↓	↓	↓	↓	↓
Opioids	↓	↔	↓/↔	↓	↓/↔	↓/↔	↔	↓
Propofol	↔	↓	↓↓	↓↓	↓↓	↓	↓↓	↓↓
Barbiturates	↑	↓	↑/↓	↓↓	↓↓	↓	↓↓	↓↓
Etomidate	↔	↔	↔	↔	↓	↔	↓	↓
Ketamine	↑	↑	↑	↑	↑/↓/↔	↔	↑↑	↔
α-2 adrenoceptor agonist	↓	↓	↔/↑	↓	↓?	↓?	↓↓	↔

↓, decrease; ↑, increase; ↔, no change; ?, unknown; HR, heart rate; CO, cardiac output; SVR, systemic vascular resistance; MAP, mean arterial pressure; ICP, intracranial pressure; CPP, cerebral perfusion pressure; CBF, cerebral blood flow; CMRO2, cerebral metabolic rate of oxygen.