Pediatric Pharm & Fluids

Question 1

Water-Soluble Medications

Answer 1

Children ↑H2O body composition
↑Vd
Examples: Succinylcholine, Bupivacaine, & antibiotics

Question 2

Fat-Soluble Medications

Answer 2

Children ↓fat & muscle mass
↓Vd
↑DOA (less tissue mass to distribute)
Examples: Fentanyl & Thiopental

Question 3

Hepatic/Renal Function

Answer 3

IMMATURE

Longer drug half-lives

Question 4

Blood-Brain Barrier

Answer 4

IMMATURE

Improved by 2yo

Question 5

Pediatric 50th Percentile Weight

Answer 5

Age (yrs) x 2 + 9 = kg

Question 6

Weight Formula < 1yo

Answer 6

Mos/2 +4

Question 7

Neonates Physiological Differences

Answer 7

↑H2O content 70-75% (adults 50-60%)
↓fat % → reduced lean muscle mass
↑ECF Vd as compared to adults

Question 8

Protein Binding

Answer 8

↓total serum protein ↑free drug available

↓barbiturates & LA dosages

Question 9

Hepatic Metabolism

Answer 9

Normal adult hepatic enzymes convert medications from lipid-soluble (non-polar) to more polar water-soluble compound

Impaired metabolism improves w/ age
↑enzyme activity ↑drug delivery to the liver

Question 10

Renal Excretion

Answer 10

Less efficient
- Incomplete glomerular development
- Low perfusion pressure
- Inadequate osmotic load
GFR & tubular function develop rapidly in 1st few months of life
Careful fluid administration to prevent fluid overload
Neonatal kidneys unable to excrete ↑amounts excess H2O or electrolytes

Question 11

What medications have a prolonged elimination half-life in neonates due to impaired renal excretion?

Answer 11

Aminoglycosides & cephalosporins

Question 12

Inhalational Agents

Answer 12

More rapid inhalation anesthetics concentration increase in the alveoli
Infants > children > adults
჻ more rapid inhalation induction
Excretion & recovery also more rapid
Potentiates NDMR actions
*Overdose occurs quickly & potentially leads to serious complications

Question 13

Respiratory Physiological Differences

Answer 13

↑RR (higher minute ventilation)

↓FRC

Question 14

Cardiovascular Physiological Differences

Answer 14

↑CO to vessel-rich groups
Immature cardiac development
Lack compensatory mechanisms
Immature myocardium
↓Ca2+ stores

Question 15

What age does MAC peak?

Answer 15

3 months old

Question 16

Stage 1

Answer 16

Analgesia or disorientation

From beginning general anesthesia induction to loss of consciousness

Question 17

Stage 2

Answer 17

Excitement or delirium
From loss of consciousness to onset automatic breathing
Eyelash reflex disappears, but other reflexes remain intact
Coughing, vomiting, & struggle may occur
Respirations irregular w/ breath-holding

Question 18

Stage 3

Answer 18

Surgical anesthesia
From onset automatic respiration to respiratory paralysis
Divided into 4 planes

Question 19

Plane 1

Answer 19

Stage 3
From onset automatic respiration to cessation eyeball movements
Eyelid reflex lost
Swallowing reflex disappears
Marked eyeball movement may occur, but conjunctival reflex lost at the bottom of the plane

Question 20

Plane 2

Answer 20

Stage 3
From cessation of eyeball movements to beginning of intercostal muscles paralysis
Laryngeal reflex lost although upper airway tract inflammation ↑reflex irritability
Corneal reflex disappears

Question 21

Plane 3

Answer 21

Stage 3
From beginning to completion intercostal muscle paralysis
Diaphragmatic respiration persists, but there’s progressive intercostal paralysis
Pupils dilated & light reflex abolished
Laryngeal reflex lost in plane 2 still able to be initiated w/ painful stimuli

Desired plane for surgery when muscle relaxants were not used

Question 22

Plane 4

Answer 22

Stage 3

From complete intercostal paralysis to diaphragmatic paralysis

Question 23

Stage 4

Answer 23

Anesthetic overdose causing medullary paralysis & vasomotor collapse

Question 24

N2O

Answer 24

Nitrous oxide
2nd gas effect
Analgesia & amnesia
Odorless
PIV placement on older children

Question 25

N2O Contraindications

Answer 25

Pneumothorax - N2O 70% doubles pneumo w/in 12min NEC Bowel obstructions contributes to PONV

Question 26

What gas law explains the 2nd gas effect?

Answer 26

Dalton's law | Total pressure = P1 + P2 + P3 + ... + P#

Question 27

What's the choice inhalational anesthesia for pediatrics? Why?

Answer 27

Sevoflurane (previously Halothane) | Least irritating to the airway

Question 28

Sevoflurane Considerations

Answer 28

Dose-related depression in RR and Vt | CO2 absorbents w/ barium hydroxide or soda lime ↑compound A production

Question 29

Isoflurane

Answer 29

Slowest & pungent Potentiates NDMR > Sevo or Des Least costly inhalational agent

Question 30

Desflurane

Answer 30

``` MOST pungent Causes airway irritation 50% laryngospasm incidence w/ induction Better utilized as maintenance Use w/ LMA controversial RAPID emergence α emergence delirium ```

Question 31

Propofol

Answer 31

``` ↑induction dose d/t ↑Vd Profound hypotension in critically-ill infants (consider Ketamine) Shorter elimination 1/2 life ↑plasma clearance rates Discard after 6 hours ↓SVR/BP → profound hypotension Dose-dependent ventilation depression Infection risk especially infants or children w/ immature/impaired immune systems ```

Question 32

Ketamine

Answer 32

``` Cerebral cortex dissociation Analgesia & amnesia Side effects include ↑secretions, vomiting, & hallucinations Admin w/ Glycopyrrolate 0.01 mg/kg Nystagmus gaze Preserves spontaneous respirations ↑SNS response ↑HR/CO/BP ↑pulmonary pressures Bronchodilation (ideal in asthmatics) ``` ``` PO 6-10mg/kg Sedation IM 2-5mg/kg Induction IV 1-2mg/kg (5-10mg/kg) Pain IV 0.5mg/kg bolus Infusion 4mcg/kg/min ```

Question 33

Etomidate

Answer 33

Pain on injection, myoclonus, anaphylactic reactions, adrenal suppression + CV stability in hypovolemic patients - adrenocortical suppression not well-tolerated in critically ill Dose-dependent ventilation depression 0.2-0.3mg/kg

Question 34

Opioids

Answer 34

More potent effects d/t immature blood-brain barrier | ↑respiratory centers sensitivity (especially infants)

Question 35

Morphine

Answer 35

0.025-0.05 mg/kg IV Histamine release → erythema & pruritis Reduced hepatic conjugation ↓renal clearance

Question 36

Fentanyl

Answer 36

Synthetic opioid agonist - analgesia & blunts circulatory response to direct laryngoscopy 0.25-1 mcg/kg IV Infusion 0.5-2 mcg/kg/hr IV onset almost immediate Max analgesic & respiratory depression effect w/in several minutes ↑DOA 30-60min w/ high doses d/t ↓fat & muscle Neonates & preterm infants slower metabolism Dependence w/in 7 days Off-label FDA use

Question 37

Hydromorphone

Answer 37

``` Semi-synthetic opioid agonist Morphine derivative 5x more potent IV or epidural Onset 5min DOA 2-3hrs Patients w/ renal toxicity ↑risk metabolite accumulation & neuroexcitatory S/S → tremors, agitation, & cognitive dysfunction ```

Question 38

Naloxone

Answer 38

Antagonizes opioids - reduces respiratory depression, N/V, pruritis, & urinary retention 0.25-0.5 mcg/kg repeat dose until effect Max 2 mg Onset 30sec-1min Elimination 1/2 life 1.5-3hrs Overdose → systemic HTN, cardiac arrhythmias, & pulmonary edema

Question 39

Midazolam

Answer 39

Premedication: *PO 0.5 mg/kg (onset 20min) Intranasal 0.2-0.3mg/kg IV 0.05 mg/kg (onset 5min) PICU sedation infusion 0.4-2mcg/kg/min DOA 1-6hrs variable

Question 40

Flumazenil

Answer 40

``` Benzodiazepine reversal agent GABA receptor competitive antagonist Onset 5-10min IV 10mcg/kg Elimination 1/2 life ≈ 1hr ```

Question 41

Clonidine

Answer 41

``` Pre-synaptic α agonist ↓Ca2+ levels → inhibits NE release Oral premed 4 mcg/kg (onset 60-90min) Difficult to time premed Regional anesthesia adjunct Epidural/caudal 1-2 mcg/kg prolongs analgesia approximately 3hrs Residual sedation postop ```

Question 42

Dexmedetomidine

Answer 42

``` α2 adrenergic receptor agonist Anxiolysis, sedation, & analgesic properties Sedation w/o respiratory depression Elimination 1/2 life ≈ 2hrs Oral or intranasal 1 mcg/kg IV 0.25-1 mcg/kg over 10-15min Infusion 0.2-2 mcg/kg/hr ```

Question 43

NDMRs

Answer 43

↑variability w/ dose & response ↑sensitivity ↓ACh release (immature neuromuscular junction) & reduced muscle mass Fetal receptors have longer opening time → Na+ enters the cell Shorter onset up to 50% d/t ↑circulation times Prolonged DOA w/ immature hepatic system (Roc, Vec, & Panc) Difficult to monitor effect w/ peripheral nerve stimulator

Question 44

Muscle Relaxants Doses

Answer 44

Rocuronium 0.6 OR 1.2 mg/kg IV (low dose 0.3 mg/kg intubating conditions in 3min) Cisatracurium 0.15 mg/kg IV (liver transplants) Vecuronium 0.1 mg/kg IV

Question 45

Muscle Relaxant Reversal

Answer 45

Glycopyrrolate 0.01 mg/kg IV Neostigmine 0.05 mg/kg IV *Adolescent females avoid Sugammadex to prevent birth control inactivation

Question 46

Succinylcholine

Answer 46

Infants require ↑dose d/t ↑ECF Vd Pediatric patients ↑risk to experience cardiac dysrhythmias, hyperkalemia, rhabdomyolysis, myoglobinuria, masseter muscle spasm, or malignant hyperthermia Cardiac arrest → treat hyperkalemia Often avoided in routine elective pediatric surgery

Question 47

Succinylcholine Dose/Routes

Answer 47

IV (intubation) <10kg 2 mg/kg >10kg 1-2 mg/kg IM 4mg/kg IV (laryngospasm) 0.25-0.5mg/kg Atropine 0.02 mg/kg IV or IM to prevent bradycardia

Question 48

Sugammadex

Answer 48

Water-soluble sugar molecule encapsulates NDMRs IV 2-4 mg/kg 16 mg/kg after RSI dose Rocuronium 1.2 mg/kg

Question 49

Ketorolac

Answer 49

NSAID 0.5 mg/kg IV Elimination 1/2 life ≈ 4hrs Caution in impaired renal, ↑bleeding risk, & impaired bone healing Reserve for children > 1yo (UNC 6mos) when renal function more mature

Question 50

Glucose

Answer 50

Neonates - minimal glycogen stores & prone to hypoglycemia when NPO or stressed Impaired renal glucose excretion

Question 51

Hypoglycemia Treatment

Answer 51

10% dextrose 1-2 mL/kg NEVER admin D50% bolus d/t vessel necrosis & high osmolarity (2mL D50 + 8mL NS = D10%) Maintenance IV dextrose infusions Minimize preop fasting

Question 52

Dextrose 10% vs. 50% | Per cent = grams per 100mL

Answer 52

``` D50% = 50g dextrose per 100mL = 0.5g/mL D10% = 10g per 100mL = 0.1g/mL D5% = 5g per 100mL = 0.05g/mL ``` Dilution 1mL D50% in total 5mL → 0.1g/mL or D10% 1mL D50% dilute in 10mL → 0.05g/mL or D5%

Question 53

MIVF

Answer 53

0-10kg → 4mL/kg/hr per kg 10-20kg → 40mL + 2mL/kg/hr per kg >10kg >20kg → 60mL + 1mL/kg/hr per kg >20kg

Question 54

What fluid type should be utilized for NPO fluid deficits & evaporative loses?

Answer 54

Balanced salt solutions such as NS or LR

Question 55

What blood products always require a filter & warmer?

Answer 55

PRBCs FFP *Platelets only require blood filter tubing

Question 56

EBV

Answer 56

``` Premature 100mL/kg Term infant 90mL/kg 6mos 80mL/kg Children < 1yo 75mL/kg Children > 1yo 70mL/kg Adults 55-65mL/kg ```

Question 57

Volume PRBCs to be transfused FORMULA

Answer 57

[(desired Hct - current Hct) x EBV] / PRBCs Hct (≈ 60%) OR (desired Hct - current Hct) x EBV x 1.5

Question 58

When to administer FFPs?

Answer 58

Replenish clotting factors lost during massive transfusion - often when EBL exceeds 1-1.5x the EBV Observed coagulopathy Prolonged PT, PTT, or ROTEM/TEG

Question 59

Tolerated platelet counts in children w/ ITP or chemotherapy _____ mm^3

Answer 59

15,000mm^3 | Tolerate lower platelet counts to limit donor exposures

Question 60

Platelet transfusion required when _____

Answer 60

↓platelet count d/t dilution (massive blood transfusions) < 50,000mm^3 Filter only Warming → activated & sticky w/in warming device DO NOT WARM

Question 61

Cell Saver

Answer 61

``` Salvages erythrocytes (RBCs) from suctioned blood ↑volumes washed cells → coagulopathy d/t coagulation factor dilution ```

Question 62

What complications does citrate preservative cause?

Answer 62

PRBCs & FFP contain calcium citrate Rapid/multiple transfusions → hypocalcemia Neonates have impaired ability to mobilize Ca2+ & to metabolize citrate

Question 63

What does serve ionized hypocalcemia lead to?

Answer 63

Cardiac depression w/ hypotension

Question 64

Irradiated Blood Products

Answer 64

Indicated to prevent transfusion related graft vs. host disease Cancer & immunocompromised patients

Question 65

Filtered Blood Products

Answer 65

Effective way to eliminate CMV infection risk | Cancer & sickle cell patients

Question 66

Washed Blood Products

Answer 66

Reserved for patients w/ life-threatening allergic reactions Wash out WBCs Significantly ↓RBC lifespan & effectiveness in circulation

Question 67

Recommendations to prevent hyperkalemia cardiac arrest associated w/ blood transfusions:

Answer 67

- Transfuse before significant hemodynamic compromise - Use large bore PIV catheters over central lines - Fresh (w/in 5 days old) & washed RBCs Hct goal ↑30% Earlier transfusions

Question 68

Hyperkalemia Treatment

Answer 68

``` Hyperventilation Ca2+ chloride 20mg/kg IV or Ca2+ gluconate 60mg/kg Dextrose 0.25-1g/kg + insulin 0.1units/kg IV Sodium bicarbonate 1-2mEq/kg IV Albuterol Furosemide 0.1mg/kg IV Cardiac arrest → CPR Activate ECMO (arrest > 6min) ```

Question 69

PRBCs

Answer 69

Infants 30-40% Child 25% 10-15mL/kg ↑Hgb 2-3g/dL

Question 70

FFP

Answer 70

Massive blood transfusion 10-15mL/kg ↑factor levels 15-20%

Question 71

Platelets

Answer 71

Count < 100,000mm^3 5-10mL/kg ↑platelets 50-100,000

Question 72

Cryoprecipitate

Answer 72

Persistent bleeding 10-20mL/kg ↑fibrinogen 60-100mg/dL

Question 73

Calcium Chloride

Answer 73

Hypocalcemia 10mg/kg IV slow admin via central line

Question 74

Calcium Gluconate

Answer 74

Hypocalcemia 30mg/kg IV slow admin via peripheral line