8. Neonatal Ventilation Flashcards
What are the indications of neonatal ventilation? (Hint: 6 things)
- Resp failure: despite O2 and NIV
- Vent failure: PaCO2 > 55/60 mmHg, pH < 7.25/7.20
- Impaired pulmonary function: ↓ compliance & ↑ resistance, RDS, MAS, pneumonia, pneumo
- Neuro Compromise: Apnea of Prematurity, drug depression
- Impaired CV Function: PPHN, congenital heart disease, shock
- Post-Op: Sedation depressing resp drive
What are the harmful effects that can occur from neonatal ventilation? (Hint: 8 categories)
- Barotrauma: from PPV, Air Leaks (Pneumo, pneumomediastinum, PIE)
- Volutrauma: Overdistention/underdistention
- Patient/Vent Dys-synchrony (can lead to baro & volutrauma)
- Atelectrauma: Repetitive opening and closing of atelectatic lung units
- Biotrauma: Effect of oxidant stress and inflammation
- Hemodynamics: ↓ venous return, ↓ CO, ↓ pulm perfusion
- Neurologic: Intracranial hemorrhage, changes in cerebral blood flow
- Oxygenation: Oxygen toxicity, ROP
- What can ventilator induced lung injury (VILI) lead to?
- What are the characteristics of an injured alveoli during the acute phase? (think of the sick alveoli picture greg always uses!)
- BPD
- Necrotic type 1 cells, inactivated surfactant, hyaline membrane, widened and edematous interstitium, swollen and injured epithelial cells
- What pressure(s) did Hernandez use on his rabbits when he ventilated them?
- What did Hernandez discover?
- PIP of 30 and 45 cmH2O
- Using a plaster cast that wrapped around the lungs and thorax protected the rabbit from having lung damage at even 45 cmH2O pressure, whereas the rabbits with no cast had damage to the lungs.
- This shows that too much volume can cause trauma to the lungs as well.
With respect to volutrauma, what would happen if:
- high Vt, low PEEP
- normal Vt, high PEEP
- Normal Vt, low PEEP
- Lungs atelectatic, overdistention on insp of alv
- Overdistention
- Atelectatic
How is flow preferably measured in pediatrics and why?
Proximal airway flow sensors (external flow sensors), because they are faster, more accurate, and sensitive
(peds needs very sensitive flow sensors because they get very small tidal volumes)
- What is compressible volume?
- If the vent measures Vt internally, what do you have to be aware of?
- What do newer vents calculate during a pre-use check, and what does this do? What about older vents?
- What is the difference in how compressible volume is calculated b/w the Servo I & the VN500/Avea?
- Volume lost to expansion of the vent circuit and humidifier
- If the reading is compensated for compressible volume or not
- Tubing compliance, this automatically compensates for expansion of the circuit during pressurization
- Older vents can’t compensate - Servo I can turn on/off compensation for compressible volume, VN500/Avea calculates compressible volume & measures Vt at pt Y flow sensor
- What is a normal RR (frequency) to set on a neonatal ventilator?
- If the baby has spontaneous drive in respiratory distress, how high can the RR be?
- 30-50 bpm
2. > 60-70 bpm
- What is a normal Vt target in neonates?
2. What patients may this be elevated in? (Give disease example too)
- 4-6 mL/kg
2. Pts with ↑ anatomical deadspace (ex. BPD, sometimes ventilate 6-8 mL/kg)
- How is PIP set on neonatal ventilators?
- What is the normal PIP range for infants?
- What is this limited to in premature infants?
- What is this limited to in term and older infants?
- To achieve desired Vt and chest rise
- 15-22 cmH2O
- < 25 cmH2O
- < 30 cmH2O
- How is Ti set in neonatal ventilation?
- What happens if the Ti is long?
- What happens if the Ti is short?
- What is the rule of thumb to figure out Ti based on ETT size?
- Based on disease pathology and time constants
- Improves oxygenation, negative feedback inhibiting spont. respirations
- Prevents effective Vt delivery, excessive PIP needed to deliver Vt
- Size of ETT/10
- What is the normal PEEP range for neonates, and where do you generally start?
- Since PEEP improves oxygenation, what else improves?
- What do you adjust PEEP based on?
- What do you need to be aware of when changing PEEP? (also…. when setting PIP what happens when you ↑ PEEP, and what happens if you’re setting ΔP?)
- 5-10 cmH2O, start at 5-7 cmH2O
- FRC!
- Pts oxygenation, CXR
- Vt changes! When setting PIP, increasing PEEP will cut into ΔP, and since PIP stays the same, it therefore ↓Vt. When setting ΔP, increasing PEEP will cause a jump in PIP equal to jump in PEEP, so no change in Vt.
- What is the expected SpO2 in a premature neonate (< 37 wks)?
- What is the expected SpO2 in a term neonate ( 37 wks - 1 month)?
- 90-94%
2. >/= 92%
- What does too high of a MAP cause?
- What dies too low of a MAP cause?
- What are characteristics of the “most appropriate map”?
- Barotrauma, overdistention
- Atelectasis, atelectrauma
- Enhances oxygenation and minimizes risks of barotrauma and volutrauma
What parameters can you change (↑) on the vent to ↑ MAP?
Flow/rise, PIP, Ti, PEEP, RR