Anatomic, Physiologic and PK differences in Children Flashcards Preview

PT: Nutrition Exam 2 > Anatomic, Physiologic and PK differences in Children > Flashcards

Flashcards in Anatomic, Physiologic and PK differences in Children Deck (53)
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1
Q

What did the FDA Modernization Act do?

A

Extension of patient life if pediatric studies done

2
Q

What did the Best Pharmaceuticals for Children Act do?

A

NIH funding for pediatric studies

3
Q

What did the Pediatric Research Equity Act do?

A

Manufactures must submit pediatric data with every new NDA if the drug has potential use in children

4
Q

Define Gestational Age

A

of weeks from the onset of the mother’s last menstrual period

5
Q

Define Postnatal Age

A

chronological age after birth

6
Q

Define Postmenstrual Age (PMA):

A

gestational age PLUS postnatal age

7
Q

Define Neonate

A

< 1 month

-Preterm or premature: <37 weeks gestation

8
Q

Define Infant

A

< 1 year

9
Q

Define Child

A

1-11 years

10
Q

Define Adolescent

A

12-18 years

11
Q

What are A & P differences in children?

A
  1. CV
  2. Neurological
  3. Pulmonary
  4. GI
  5. Renal
  6. Fluid/Electrolytes
  7. Dermatological
12
Q

What are the CV differences in children?

A
  1. Circulation
  2. Cardiac Output (strove volume & HR)
  3. BP
13
Q

What is notable about fetal circulation (3)?

A
  1. High pulmonary pressures (fluid filled lungs)
  2. Low systemic vascular resistance (SVR)
  3. Right ventricle is systemic ventricle (wall thickness and muscle mass decrease with postnatal age
14
Q

What occurs during postnatal circulation?

A
  1. Pulmonary pressures decrease (air filled lungs)
  2. SVR increases (ductus venosus, arterioles, and foramen oval CLOSE
  3. Left ventricle is systemic ventricle (CO doubles)
15
Q

What are the trends in cardiac output from newborn to adolescence?

A
  1. CO: Increases
  2. HR: Decreases
  3. SV: Increases
16
Q

Heart Rate in pediatrics

A

-Tachycardia is the most efficient method of increasing CO
(Most important VS, Peds patients are HR dependent)
-Limites cardiac reserves
(bradycardia is the most common terminal arrhythmia in infants)

17
Q

Blood Pressure in pediatrics

A
  • Normal BP in peds patients is determined by: height %ile, age, gender
  • MAP is used in neonates (equal to gestational age)
  • SBP is used to define HTN in infants < 1 year
18
Q

What is the value of normal BP in SBP or DBP %ile?

A

<90th

19
Q

What is the value of prehypertension BP in SBP or DBP %ile?

A

90th to =95th (or if BP exceeds 120/80)

20
Q

What is the value of Stage 1 HTN in SBP or DBP %ile?

A

95th to 99th + 5 mmHg

21
Q

What is the value of stage 2 HTN in SBP or DBP %ile?

A

> 99th + 5mmHg

22
Q

How can you dx HTN in peds patients?

A

must have 3 separate BP measurements on 3 separate occasions

23
Q

What are normal blood volumes in children

A
Infant = 80 mL/kg
Child-Ado = 70 mL/kg
24
Q

What are neurological difference in children?

A
  1. Increased BBB permeability
    - easier diffusion of drugs
    - increased diffusion of bilirubin into the CNS
25
Q

What is the difference in the control of breathing in children?

A
  1. Premature Infants = immature respiratory drive and decreases sensitivity to CO2
  2. Apnea of prematurity
    =req. tactile stimulation
    =caffeine citrate
26
Q

What are the pulmonary differences in children?

A
  1. Airway size
  2. Surfactant
  3. Respiratory muscles
27
Q

What is notable of the pediatric airways?

A
  1. All conducting airways are present at birth

2. Small reduction in airway radium have greater impact on airflow (secretions/inflammation)

28
Q

What is surfactant?

A
  1. Production occurs at 34-36 weeks gestation
  2. It coats the surface of the alveoli (decreases surface tension & prevents collapse)
    * 3. Surfactant deficiency is the principle cause of respiratory distress in the NICU*
29
Q

What are the respiratory muscles?

A
  1. Intercostal muscles are not fully developed

2. Diaphragm is the primary resp. muscle until school age

30
Q

What is nasal flaring/why is it important?

A
  1. infants are obligate nasal breathers (nasal congestion)

2. important sign of respiratory disress

31
Q

What pattern does respiratory rate of children follow with adults?

A

resp. rate decreases as age increases

32
Q

What are the GI differences?

A
  1. Decreased gastric acid production
  2. Delayed gastric emptying
  3. Decreases muscle mass (less forceful contraction)
  4. Decreases intestinal flora
33
Q

What are the renal differences?

A
  1. All nephrons are present at birth
  2. Decreases ability to concentrate urine (d tubular length & d response to ADH)
  3. Decreased GFR (d BF)
  4. Decreased tubular secretions and reabsorption (d frug clearance)
  5. Long-term diuretic use not good
34
Q

What is the Schwartz equation for CrCl?

A

CrCl = K x L/Scr

K= age specific constant
L = length in cm
S= serum [Cr]
35
Q

What is the Traub equation?

A

CrCl = 0.48 x L/Scr

L= lenght
Scr = serum [Cr]
36
Q

When monitoring renal function what is normal serum creatinine?

A

Infants: < 0.6 mg/dL

Children/Ado: 0.6-1 mg/dL

37
Q

When monitoring renal function what is normal urine output?

A

Infants/Children: 1-2 mL/kg/hr

Ado/Adults: 0.5 mL/kg/hr

38
Q

What trends do you need to monitor in renal function (2)?

A
  1. Serum creatinine

2. Urine output!!!!!!!

39
Q

How can you calculate total body water?

A

TBW = ECF + ICF

40
Q

What percent of the body weight is water in respective ages?

A

Adults: 60%
Infants: 75%
Premature Infants: >/= 83%

41
Q

How much water weight do babies lose in the first week of life?

A

5-15%

42
Q

What are the dermatological differences in pediatrics?

A
  1. Immature stratum corneum in infants <34 weeks (I water loss, decreases barrier protection)
  2. Larger surface area to body mass ratio
43
Q

What are the PK differences in children?

A

ADME

44
Q

What is different in GI absorption in children?

A
  1. Increased gastric pH in infants
  2. Delayed gastric emptying
    Normal by ~4 months of age
45
Q

What is different in percutaneous absorption in children?

A
  1. Increased absorption of topical agents in neonates (due to increased SA)
  2. Increased risk of systemic toxicity
46
Q

What is different in IM absorption in children?

A
  1. Poor and erratic IM absorption in neonates (due to decreased muscle mass and actions)
  2. IM absorption is more reliable in infants
  3. Drugs administered IM to neonates and infants
47
Q

What is different in distribution for children?

A
  1. Increased Vd of water soluble drugs = higher doses

2. Decreased Vs of fat soluble drugs = lower doses

48
Q

What is different in the protein binding in children?

A
  1. Decreased albumin and alpha1-acid glycoprotein concentrations
  2. Increased fraction of free drug (increased toxicity)
    Normal values approached at 10-12 months of age
49
Q

What is the difference in metabolism in children?

A
  1. Both Phase I and Phase II reactions are significantly reduced in the newborn
  2. CYP450 activity greater in early childhood
50
Q

What is different about Phase II reactions in children?

A
  1. Decreased glucuronidation

2. Decreased glycine conjugation

51
Q

What is different about elimination in children?

A
  1. Decreased Cl in renal eliminated drugs in neonates/infants
    - Decreased Cl = t1/2
  2. Dynamic changes in GFR, tubular secretion, and tubular reabsorption
52
Q

What is difference in the pharmacy in pediatrics?

A
  1. Weight-based dosing

2. Age-specific dosing

53
Q

What are the pediatric handbooks available?

A
  1. Pediatric Dosage Handbook
  2. Neofax
  3. Pediatric Injectable Drugs