Mod IV: Inhalational anesthetic & Intravenous Anesthetic Induction agents

Question 1

_{Inhalational anesthetic agents}

Anesthetic requirement is HIGHEST in infants between 2-3 mos. Why?

Answer 1

Reasons not adequately explained

It has been suggested that neuronal density, metabolic rate, oxygen consumption and brain water have contributed to this alteration from birth; however the precise mechanism remains unclear.

Question 2

_{Inhalational anesthetic agents}

Anesthetic requirement is HIGHEST in infants between 2-3 mos. •Exception:

Answer 2

MAC of Sevoflurane same for neonates & infants

Question 3

_{Inhalational anesthetic agents}

What’s the order of decreasing Inhalational anesthetic requirements from Infants to Adults?

Answer 3

INFANTS > TERM NEONATE > PREMATURE NEONATE > OLDER CHILDREN > ADULTS

_ITPOA

Question 4

_{Inhalational anesthetic agents}

What’s 1.0 MAC of Halothane for Infants, Neonates, Small children, and Adults?

Answer 4

Infants: 1.1-1.2

Neonates: 0.87

Small children: 0.87

Adults: 0.75

Question 5

_{Inhalational anesthetic agents}

What’s 1.0 MAC of Isoflurane for Infants, Neonates, Small children, and Adults?

Answer 5

Infants: 1.8-1.9

Neonates: 1.6

Small children: 1.3-1.6

Adults: 1.2

Question 6

_{Inhalational anesthetic agents}

What’s 1.0 MAC of Desflurane for Infants, Neonates, Small children, and Adults?

Answer 6

Infants: 9-10

Neonates: 8-9

Small children: 7-8

Adults: 6.0

Question 7

_{Inhalational anesthetic agents}

What’s 1.0 MAC of Sevoflurane for Infants, Neonates, Small children, and Adults?

Answer 7

Infants: 3.2

Neonates: 3.2

Small children: 2.5

Adults*: 2.0

Note that MAC of Sevoflurane same for neonates & infants

Question 8

_{Inhalational anesthetic agents}

There is Higher alveolar ventilation to FRC ratio. What does this mean?

Answer 8

Increased alveolar ventilation

Reduced FRC

Question 9

_{Inhalational anesthetic agents}

How are Blood/Gas coefficients in neonates

Answer 9

Blood/Gas coefficients reduced in neonates

Question 10

_{Inhalational anesthetic agents}

Blood/Gas coefficients reduced in neonates. What else alters the uptake of the agent? What’s the Ultimate effect?

Answer 10

Greater blood flow to vessel rich organs also alters the uptake of the agent

Ultimate effect = FASTER rate of inhalation induction

Question 11

_{Inhalational anesthetic agents}

Why is there a FASTER rate of inhalation induction with neonates?

Answer 11

Higher alveolar ventilation to FRC ratio, which results in Increased alveolar ventilation & Reduced FRC

Blood/Gas coefficients reduced in neonates

Greater blood flow to vessel rich organs

Question 12

_{Inhalational anesthetic agents}

What properties must the ideal Inhalational Anesthetic have?

Answer 12

Pleasant smell

Rapid onset & elimination

Minimal respiratory irritant properties

No CV depression

No respiratory depression

Little effect on cerebral and cardiac Blood Flow

Minimal interaction with catecholamines

Should not be metabolized to toxic compounds

Question 13

_{Inhalational anesthetic agents}

Why is Sevoflurane the Preferred for inhaled induction in pediatrics

Answer 13

Has some of the properties of the ideal agent, including

Less pungent

low blood/gas coefficient

^{Rapid induction/ emergence}

Enhanced CV safety profile

^{Less bradycardia, arrhythmias, & hypotension}

Least respiratory depression

Decreased incidence of laryngospasm & breath holding during induction

Question 14

_{Inhalational anesthetic agents}

Although (questionable, providers often induce w/ Sevo but then switch to isoflurane for maintenance; why

Answer 14

—Sevo is a/w increased incidence of emergence delirium

Question 15

_{Inhalational anesthetic agents}

How could “Emergence delirium” a/w Sevo in peds be attenuated?

Answer 15

Sedation/preemptive analgesia

(e.g. Midazolam)

Question 16

_{Inhalational anesthetic agents}

What are Concerns regarding metabolism of sevoflurane?

Answer 16

Fluoride toxicity

Compound A toxicity

Question 17

_{Inhalational anesthetic agents}

Although No reported instances of nephrotoxicity attributed to inorganic fluoride production during sevoflurane anesthesia in pediatric, why is the use Sevoflurane contraindicated in children with limited renal reserve?

Answer 17

Subtle urinary markers of occult renal damage have been demonstrated with prolong use, therefore use probably contraindicated in children with limited renal reserve

Question 18

_{Inhalational anesthetic agents - Halothane}

Halothane was well tolerated for inhaled induction; why?

Answer 18

Less airway tract irritation (< laryngospasm)

Less breath holding

Question 19

_{Inhalational anesthetic agents - Halothane}

Muscle relaxant properties of Halothane are evidenced by:

Answer 19

Facilitate induction/intubation w/o use muscle relaxant

Potentiates NDMBs

Question 20

_{Inhalational anesthetic agents - Halothane}

What was the benefit of using Halothane for SLOW AND STEADY induction in asthmatic?

Answer 20

Halothane is a Potent bronchodilator

However, largely replaced by sevoflurane

Question 21

_{Inhalational anesthetic agents - Halothane}

Why was Halothane replaced if it seems so ideal?

Answer 21

Greatest cardiovascular depression

^{Hypotension, bradycardia, arrhythmias}

^{Dose dependent}

Sensitizes the myocardium to catecholamines

^{Ventricular arrhythmias common}

^{Limit dose to 10 ug/kg of epinephrine}

Halothane hepatitis?

^{Contraindicated in patient with hepatic dysfunction}

^{More common in adult than pediatric population}

High blood/gas coefficient (2.5)

^{Slow rate of inhaled induction}

Question 22

_{Inhalational anesthetic agents}

Which Inhalational anesthetic agents causes the Greatest cardiovascular depression? How does it manifest?

Answer 22

Halothane

Manifest as Hypotension, bradycardia, arrhythmias

In a Dose dependent manner

Question 23

_{Inhalational anesthetic agents}

Which Inhalational anesthetic agent Sensitizes the myocardium to catecholamines? How does it manifest?

Answer 23

Halothane

Ventricular arrhythmias common

Limit dose to 10 ug/kg of epinephrine

Question 24

_{Inhalational anesthetic agents - Halothane}

Why is Halothane contraindicated in patient with hepatic dysfunction?

Answer 24

Halothane hepatitis

More common in adult than pediatric population

Question 25

_{Inhalational anesthetic agents - Halothane} Why does Halothane have a slow rate of inhaled induction?

Answer 25

High blood/gas coefficient (**2.5**)

Question 26

_{Inhalational anesthetic agents - Halothane} T/F: Halothane is no longer available in the US

Answer 26

**True** May still be available oversea

Question 27

_{Inhalational anesthetic agents} Between Halothane and Isoflurane, which agent has Less cardiac depression

Answer 27

**Isoflurane**

Question 28

_{Inhalational anesthetic agents} What's the primary cause of hypotension w/ Isoflurane?

Answer 28

**Vasodilation**

Question 29

_{Inhalational anesthetic agents} What's the primary cause of hypotension w/ Halothane?

Answer 29

**Myocardial depression**

Question 30

_{Inhalational anesthetic agents} Why is Isoflurane not ideal for inhalation induction?

Answer 30

Pungent odor/potential airway irritant High incidence laryngospasm Not suitable for inhalation induction

Question 31

_{Inhalational anesthetic agents - Isoflurane} Isoflurane has a Moderate rate uptake and elimination. What's its Blood/gas coefficient?

Answer 31

Isoflurane Blood/gas coefficient is **1.46**

Question 32

_{Inhalational anesthetic agents - Isoflurane} What makes Isoflurane attractive for neurosurgical procedures?

Answer 32

A/w **smaller increases in CBF** than the other volatile agents

Question 33

_{Inhalational anesthetic agents - Desflurane} Desflurane is a/w rapid induction, rapid alteration of anesthetic depth, and rapid emergence. What's Desflurane blood gas solubility coefficient?

Answer 33

Desflurane blood gas solubility coefficient is (**0.42**)

Question 34

_{Inhalational anesthetic agents - Desflurane} Why is Desflurane not suitable for nhalational inductions?

Answer 34

Pungent odor Respiratory tract irritant (breath holding, apnea, laryngospasm)

Question 35

_{Inhalational anesthetic agents - Desflurane} Desflurane is highly a/w Emergence delirium highest. How could this be Attenuated?

Answer 35

Sedation and Preemptive analgesia

Question 36

_{Inhalational anesthetic agents - Nitrous Oxide} What's the most common reason for using Nitrous Oxide in Peds?

Answer 36

Second gas effect

Question 37

_{Inhalational anesthetic agents - Nitrous Oxide} Why does the use of Nitrous Oxide needs supplementation with adjunct agents?

Answer 37

Potent analgesic, but Weak anesthetic!!!

Question 38

_{Inhalational anesthetic agents - Nitrous Oxide} What are characteristics of Nitrous Oxide that make it suitable for use frequently during induction and for 2nd gas effect

Answer 38

Very low blood gas coefficient→ extremely rapid uptake and elimination Decreases MAC by 25% when used with inhalational agents ^{Exception: desflurane & sevoflurane}

Question 39

_{Inhalational anesthetic agents - Nitrous Oxide} Decreases MAC by 25% when used with inhalational agents. What are Exceptions?

Answer 39

Desflurane & Sevoflurane

Question 40

_{Inhalational anesthetic agents - Nitrous Oxide} What concentration of Nitrous Oxide depresses swallowing reflex?

Answer 40

50%

Question 41

_{Inhalational anesthetic agents - Nitrous Oxide} What are Contraindications for use of Nitrous Oxide?

Answer 41

...

Question 42

_{Intravenous Anesthetic Agents - PROPOFOL} Larger doses of Propofol are required in peds, why?

Answer 42

Larger volume of distribution

Question 43

_{Intravenous Anesthetic Agents - PROPOFOL} PROPOFOL induction dose \< 2yrs =

Answer 43

3-4 mg/kg

Question 44

_{Intravenous Anesthetic Agents - PROPOFOL} PROPOFOL induction dose \> 2yrs =

Answer 44

2-3 mg/kg

Question 45

_{Intravenous Anesthetic Agents - PROPOFOL} PROPOFOL induction dose in adults:

Answer 45

1-2 mg/kg

Question 46

_{Intravenous Anesthetic Agents - PROPOFOL} Dose for maintenance is higher compared to adults; why?

Answer 46

Rapid redistricbution Rapid metabolism and clearance

Question 47

_{Intravenous Anesthetic Agents - PROPOFOL} Porpofol not licensed for sedation in children d/t

Answer 47

Risk of **"Propofol infusion syndrome**", which cause Metabolic acidosis Refractory Bradycardia Rhabdomyolosis Hepatomegaly

Question 48

_{Intravenous Anesthetic Agents - PROPOFOL} PROPOFOL is a/w More rapid recovery following continuous infusion; why?

Answer 48

Shorter **elimination** ½ lives Higher **plasma clearance**

Question 49

_{Intravenous Anesthetic Agents - PROPOFOL} T/F: Recovery from single bolus of PROPOFOL is appreciably different

Answer 49

**False** Recovery from single bolus not appreciably different

Question 50

_{Intravenous Anesthetic Agents - PROPOFOL} T/F: PROPOFOL infusion rate must be increased for maintenance

Answer 50

**True** Increased infusion rates for maintenance (up to **250 ug**/kg/min)

Question 51

_{Intravenous Anesthetic Agents - PROPOFOL} PROPOFOL is Effective in blunting airway responses. Which drug has it replaced for asthmatics?

Answer 51

**Ketamine**

Question 52

_{Intravenous Anesthetic Agents - PROPOFOL} T/F: PROPOFOL is More painful on injection in pediatric patient

Answer 52

**True**

Question 53

_{Intravenous Anesthetic Agents - PROPOFOL} PROPOFOL Lacks “hang-over” effect; why?

Answer 53

Low context-sensitive ½ life

Question 54

_{Intravenous Anesthetic Agents - PROPOFOL} T/F: PROPOFOL lacks propensity to cause PONV

Answer 54

True

Question 55

_{Intravenous Anesthetic Agents - PROPOFOL} T/F: PROPOFOL is a/w **less emergence agitation**

Answer 55

**True**

Question 56

_{Intravenous Anesthetic Agents - PROPOFOL} Why is PROPOFOL not recommended for prolonged sedation of critically ill pediatric patient?

Answer 56

**“Propofol Infusion Syndrome”** _{Could cause:} Metabolic acidosis Hemodynamic instability Hepatomegaly Rhabdomyolysis Multi-organ failure

Question 57

_{Intravenous Anesthetic Agents} Intravenous Anesthetic Agent that is classified as an NMDA receptor antagonists, is a/w Dissociative anesthesia that cause sedation, is often use in the induction of general anesthesia, and also has some analgesic properties:

Answer 57

**Ketamine**

Question 58

_{Intravenous Anesthetic Agents - Ketamine} Clinically useful IV doses for Ketamine is:

Answer 58

1-2 mg/kg IV

Question 59

_{Intravenous Anesthetic Agents - Ketamine} Clinically useful IM doses for Ketamine is:

Answer 59

3-4 mg/kg IM

Question 60

_{Intravenous Anesthetic Agents - Ketamine} —Why do Neonates and infants require slightly higher doses of Ketamine?

Answer 60

More **_resistant to hypnotic effects_**

Question 61

_{Intravenous Anesthetic Agents - Ketamine} What are respiratory benefits of using Ketamine?

Answer 61

Preserves airway reflexes Maintains respiratory drive Excellent bronchodilator

Question 62

_{Intravenous Anesthetic Agents - Ketamine} Administration of an anticholinergic w/ Ketamine is to minimize which effect:

Answer 62

**Increased secretions** → coughing, gagging, laryngospasm

Question 63

_{Intravenous Anesthetic Agents - Ketamine} What are Emergence concerns w/ Ketamine?

Answer 63

Hallucinations/bad dreams ^{Midazolam MAY attenuate but not reliable} PONV Delayed awakening

Question 64

_{Intravenous Anesthetic Agents - Ketamine} Ketamine Largely been replaced by propofol for almost all clinical uses except for:

Answer 64

_Brief sedation_ for painful procedures (burns, dressing changes) IM as sedative for _uncooperative developmentally delayed patient_

Question 65

_{Intravenous Anesthetic Agents - THIOPENTAL} Neonates/infants induction dose for THIOPENTAL

Answer 65

3-4 mg/kg

Question 66

_{Intravenous Anesthetic Agents - THIOPENTAL} Why are Neonates/infants More sensitive to THIOPENTAL?

Answer 66

Immature blood-brain barrier Less protein binding

Question 67

_{Intravenous Anesthetic Agents - THIOPENTAL} Why is THIOPENTAL a/w Longer elimination ½ life and Impaired clearance

Answer 67

Immature hepatic metabolism/function

Question 68

_{Intravenous Anesthetic Agents - THIOPENTAL} Children induction dose for THIOPENTAL:

Answer 68

5-6 mg/kg

Question 69

_{Intravenous Anesthetic Agents - THIOPENTAL} THIOPENTAL volume of distribution in children:

Answer 69

**Larger** volume of distribution

Question 70

_{Intravenous Anesthetic Agents - THIOPENTAL} THIOPENTAL elimination ½ life in children:

Answer 70

**Shorter** elimination ½ life

Question 71

_{Intravenous Anesthetic Agents - THIOPENTAL} THIOPENTAL Plasma clearance in children:

Answer 71

Plasma clearance is greater

Question 72

_{Intravenous Anesthetic Agents - ETOMIDATE} Clinical use of ETOMIDATE in pediatric patients is limited to:

Answer 72

Traumatized, hypovolemic patient Cardiomyopathy Decreased CV function

Question 73

_{Intravenous Anesthetic Agents - ETOMIDATE} Dose range of ETOMIDATE in peds:

Answer 73

0.2 – 0.3 mg/kg IV

Question 74

_{Intravenous Anesthetic Agents - ETOMIDATE} Side-effects of ETOMIDATE in peds include:

Answer 74

Pain on injection Myoclonus Vomiting _{Side-effects of ETOMIDATE in peds are similar to those in adults}

Question 75

_{Intravenous Anesthetic Agents} Alpha 2 agonist similar to clonidine, often used as an infusion to assist with emergence delirium

Answer 75

Dexmedetomidine (Precedex)

Question 76

_{Intravenous Anesthetic Agents - Dexmedetomidine (Precedex)} T/F: Dexmedetomidine (Precedex) has NO set DOSE

Answer 76

True

Question 77

_{Intravenous Anesthetic Agents - Dexmedetomidine (Precedex)} Review these two studies about Dexmedetomidine (Precedex)

Answer 77

http: //www.ncbi.nlm.nih.gov/pubmed/16101707 http: //www.aana.com/newsandjournal/documents/dexmedetomidine\_0611\_p219-224.pdf

Question 78

_{Intravenous Anesthetic Agents - Dexmedetomidine (Precedex)} Single-dose dexmedetomidine reduces agitation and provides smooth extubation after pediatric adenotonsillectomy

Answer 78

**True** The study referenced below concluded that 0.5 ug/kg dexmedetomidine reduces agitation after sevoflurane anesthesia in children undergoing adenotonsillectomy *Source: http://www.ncbi.nlm.nih.gov/pubmed/16101707*