CVP changes - peds and geriatric Flashcards
1
Q
cardiopulm changes from neonate to adult
A
- HR down with age
- BP up with age
- RR down with age
- Vt up with age
- PaO2 up with age
- PaCO2 up with age
- pH up with age
- infant Hgb F - higher O2 affinity – carries O2 better, makes up for less overall O2
2
Q
fetal circulation
A
- pressure on R > L due to afterload/resistance to ejection (opposite of postnatal)
- R -> L shunt (increased pulmonary vascular resistance (PVR in RV) vs systemic vascular resistance (SVR in LV)
- only about 10% of combined ventricular output goes through lungs
- shunts: foramen ovale, ductus arteriosus, ductus venosus
TPR = PVR + SVR
3
Q
3 anatomic shunts in fetal circulation
A
- foramen ovale: between R and L atrai
- ductus arteriosus: PA (R) to aortic arch (L)
- ductus venosus: placenta to IVC
FO and DA are intracradiac, DV is extracardiac
4
Q
foramen ovale
A
- allows blood to flow from R to L atrium, bypassing lungs
- intracardiac
5
Q
ductus arteriosus
A
- intracardiac
- allows blood flow from pulmonary artery to aorta, bypassing fetal lungs
6
Q
ductus venosus
A
- extracardiac
- connects umbilical vein and inferior vena cava - bypasses portal circulation
7
Q
blood flows R to L before birth due to [ ] and switches after because
A
- due to vascular resistance and afterload
- switches after because fluid squeezed out of lungs in birth – PVR down, CO up, lungs take over for gas exchange
8
Q
fetal circulation
A
- high pulmonary vascular resistance (PVR) - RV pressures high
- low systemic vascular resistance (SVR) due to placenta circulation - LV pressures low
- right to left shunt via PFO and DA
- highly reactive to hypercapnia (increased CO2)/acidosis and hypoxemia (low O2)
- at birth: O2 in lungs cause pulmonary vasculature to dilate (PVR down)
- leads to pulmonary vascular vasoconstriction and increase PVR in utero
9
Q
transition from neonate to newborn (aeration and expansion of lungs)
A
- inflating lungs initiates gas exchange over 8 years
- opening of alveoli opens associated vascular units
- rising PaO2 leads to dilation of pulmonary arterioles – decreased PVR, decreases right heart pressure
- RA pressure decreases, prevents blood shunt - flap in LA
10
Q
more transition from neonate to newborn
A
- removal of placenta circulation increases SVR
- increased aorta and left heart pressures
- foramen ovale (FO) flap closes - increases blood flow to lungs
- shunting thru ductus arteriosus decreases
- functional closure associated with increased oxygenation (increased PaO2) and decreased production of vasodilator substances
- anatomic closure occurs later (week to months)
11
Q
newborn
A
- foramen ovale closes
- anatomical closure ~2-3 months
- left heart pressure > right heart pressure: SVR > PVR, LV compliance < RV compliance
- ductus arteriosus closes
- functional closure/constriction ~15-72 hours
- anatomical closure ~2-3 weeks
12
Q
in newborn, persistance of shunts (heart/vascular defect) can lead to
A
- altered circulation and altered blood gases (PaCO2, PaO2)
- altered blood gases will depend upon SVR:PVR - cyanosis versus acyanosis
13
Q
congenital heart defects
A
- PDA: patent ductus arteriosis
- PFO: patent foramen ovale
14
Q
right to left shunt is [ ]
left to right shunt is [ ]
factors that determine shunt direction [ ]
A
- fetal - normal fetal is R > L
- post-natal - L > R
- pressures determine direction
15
Q
normal heart pressures
A
16
Q
atrial septal defects (ASD)
A
17
Q
ventricular septal defects (VSD)
#1 most common congenital heart defects in newborns
A
23
Q
atrial septal defect (ASD)
A
- patent foramen ovale (FO)
- allows blood flow between right and left atria
- fetal: right to left shunting through FO is normal
- birth/transitional circulation: FO should close due to increased left heart pressure (increased SVR, no shunt)
24
Q
ventricular septal defect (VSD)
A
- abnormal communication between right and left ventricular chambers of the heart
- most common CHD
- shunting depends on ventricular pressures – usually L to R shunt
- increased CO through pulmonary circulation - increase RV filling: can lead to RV failure
- may lead to HR and persistent pulmonary HTN of the newborn (PPHN) - overloads pulmonary circulation
- if increased PVR: right to left shunt (lung disease)
26
Q
tetralogy of fallot
A
- blue baby syndrome
- cyanotic heart disease
- tet spells: transient worsening of hypoxia f/b syncope (increased PVR) - child will often squat
- four heart defects:
1. ventricular septal defect (VSD)
2. pulmonary stenosis - pulmonary valve doesn’t open
3. right ventricular hypertrophy
4. overriding aorta
