Test 3 Flashcards
CPAP
Spontaneous ventilation with positive pressure applied to the airway throughout the respiratory cycle. Treat oxygenation failure not ventilation
Physiological effects of CPAP
Increase FRC, Increase Compliance, Decrease total airway resistance, decrease RR-> decrease WOB, Decrease intrapulmonary shunting (by opening alveoli
FRC
Forced residual capacity - normal breathing (decrease when alveoli collapse)
Indications in neonates for CPAP
- PaO2 < 50 on FiO2 60% or more with adequate ventilation
- Premature infants
- Apnea of prematurity (tx with caffeine too)
- Obstructive airway disease
- Pneumonia
- Meconium
- CHF/ Pulmonary edema
- TTN
- Paralysis of diaphragm
Contraindications of CPAP
PaCO2 >60 and pH <7.25 (not vent. adequately
- Upper airway abnormalities (cleft)
- Congenital diaphragmatic hernia
- Neuromuscular disease, CNS Depression
- Central or frequent apnea
Hazards and complications of CPAP
- decrease CO
- Decrease renal function
- Increase ICP
- Barotrauma
Nasal CPAP may result in
nasal obstruction or necrosis and gastric distension- can go into esophagus
example of nasopharyngeal tubes
LMA
CPAP generators
Flow system
stand alone CPAP machines
Mechanical vent-enough flow (flowmeter/generator)
*important to have manometer in line
CPAP has failed if
- PaO2 < 50 and FiO2 0.8-1.0
- CPAP > 8-12
- pH > 7.25
- Marked retractions/ nasal flaring/ retractions on CPAP: wob
- Frequent apnea
Weaning from CPAP
Patient with clinical improvement
- decrease FiO2 to 0.4-0.6
- decreased CPAP by 2cmH2O increments as tolerated by pulse ox or ABGs
- At CPAP of 2-3 cmH2O extubate
SiPAP
similar to APRV -Spontaneous breathing at two levels -Not synchronized -Sigh Breath Ti 1-3 seconds Rate sets how often Breaths spontaneously through Ti 2-3 cmH2O above baseline Recruits alveoli
Indications for BiPAP
Increased WOB (HIGHER RR, RETRACTIONS, PARADOXICAL BREATHING) Hypoventilation (INCREASED CO2 AND LOW PH) Airway obstruction (OSA, STRUCTURAL ABNORMALITIES)
BiPAP ventilators
Pressure Targeted-typical non-invasive vent. , IPAP and EPAP
Volume Targeted- Becoming more common on NIV, Can use volume vent via mask (dont wean)
Negative Pressure- Usually for chronic disease, not used much anymore
Contraindications of BiPAP
Cardiovascular instability Nasopharyngeal obstruction Hemoptysis (frank amnts of blood coughed up) Lots of oral secretions Agitation/anxiety Apnea Inability to maintain airway
Indications for MV of the neonate and ped pt
-Hypoxic Resp Failure
PaO2 <50 on an FiO2 > 60% despite the use of CPAP
PaCO2 <30 and pH >7.25
Nasal flaring, grunting, retractions
-Hypercapnic Resp Failure (dont vent adequately)
PaCO2 > 50 and pH <7.25
Apneic, listless, cyanotic, brandy or tachy
-Mixed also possible
-reversible problem exists
Causes of Mixed respiratory failure
Neurological alteration, Impaired resp function, impaired cardiovascular function, Post op
Most common mode for neonates
Pressure control ventilation
- time cycled, pressure limited
- peak pressure set
- vairable flow
- set Ti
- set rate
- PEEP
- No direct control of Vt
Traditional ventilation for adults
Volume ventilation
- set Vt
- Set flow unless in PRVC
- Set Ti
- Set rate
- No control over peak pressures
- More susceptible to volume lost to tubing
- PRVC and VAPS TWO TYPES OF NEW BREATHS (listed under dual control)
Dual control
PRVC and VAPS
Triggering, sensors at airway add deadspace and weight
- flow
- pressure
- motion, detects chest/ abdominal movement
- neural detects diaphragm signals
Pressure-Flow Relationship
Not usually measured
But increase in Raw will decrease Vt
Factors that cause increase Raw:
-Bronchospasm (bronchodilator)
-Airway secretions (suction)
-Inflammation (antibiotics, anti-inflammatory)
-Artificial airways (use largest possible)
Setting the vent: mode (infant)
Cpap if oxygenation only problem (PaCO2 <40)
Low SIMV if spontaneous breathing (PaCO2 < 50)
High SIMV or CMV if retaining CO2 (PaCO2 >50)
High frequency vent if no relief with above
(or surfactant replacement therapy, NO administration, ECMO)
Setting the vent : mode (peds)
Much like adult only smaller Vt (6-8)
CPAP if adequate CO2 (PaCO2 < 40)
SIMV low rates if some breathing
SIMV high rates or CMV if need more support
Peak inspiratory pressure (PIP, PAP, Pmax, etc)
Neonate 15-20cmH2O check for beaking and adjust setting
-pediatric set to achieve desired vt
Set rate
Neonate: start 40-60
term: start 25-40
pediatric: set to achieve desired Co2
Set PEEP
start 5cmH2O
Set FiO2
Neonate: keep baby pink, use TCM or Pox to keep within normal limits
Pediatric: PaO2 and or SpO2 normal limits, 100% if need for short times
Set Inspiratory Time
Low birth weight infants: 0.25 to 0.4
Term infants: 0.6-1.2
Comfort level also
Set I:E ratio
1:1.5 to 1.2
always check ratio when changing rate
Decreased compliance, stiff lungs
Crackles
decreased chest wall excursion
decreased slope of pressure volume loop
decreased tidal vol
Increased airway resistance
increased secretions
wheezes/ rhonchi
Reduced tidal volumes on same pressure-suction-stiff lungs?
Changing PaCO2
Primary: rate, 2-5 bpm per change
secondary: peak pressure, set by lung volume (watch returned volumes), watch chest excursion. Flow rate, increased flow increases Vt (watch returned volumes)
Changing PaO2
Primary: fio2 up to 60%
secondary: increase mean airway pressure
- PEEP: 5cmH2O start, increase 3-5
- Increase I time
- Increase rate
Wean infant to
FiO2 wean to < 0.4-0.5
PEEP wean by 1-2 increments to <8cmH2O
PIP wean by 1-2 to <30cmH2O
Rate wean by 1-5 to <20bpm
Wean Pediatric to
FiO2 <40%
PEEP < 5cmH2O
Rate to zero (CPAP) with or without PSV, take ETT size into account
Extubation Success indicators
Vt 3-4 ml/kg FiO2 <30% MAP <5cmH2O Oxygen Index (fiO2/ PaO2) x 100 <1.4 -leak text
High Frequency Ventilation (HFV)
Small tidal volumes, even tidal volumes below anatomic dead space
high rates 150-3000bpm
uses lower peak pressures
has not been proven to be significantly better than conventional ventilation
use with surfactant therapy there is less BPD
Indications for HFV
RDS when conventional ventilation fails
-airleaks/pneumothorax
PIE
Contraindications of HFV
COPD
Non-homogenous lung disease; leads to overdistention of good lung tissue
Hazards of HFV
Mucus pluggin
Decreased CO
Increased incidence of IVH
Difficult to assess breath sounds and heart sounds
Theory of how HVF works
Flow goes down the inside of the tube and out the outside of the tube
-alveoli have different time constants and this mode inflates all alveoli better
Types of HVF
High Frequency jet ventilation (HFJV)
High Frequency Oscillatory Ventilation (HFOV or HFO)
HFJV, HFFI, HFOV
All use bias flow
like all T piece that acts as the source of the gas blown in with the bursts of gas allow for spontaneous breathing with the HFV
HFJV
4-11 Hz (240-660 bpm) Pulse of gas to airway -special adaptor to ETT or special ETT --triple lumen: one for jet bursts, one to measure pressure in lungs, one for CV -Jet draws in air around the jet
When is HFJV used
in tandem with conventional ventilation
-conventional vent supplies sighs for development of surfactant, PEEP, and continous flow for the air entrained by the jet
HFOV or HFO
8-15Hz
Piston or pump or diaphragm (loud speaker)
uses positive and neg pressure
bias flow is driven into the ETT by the oscilator
Expired air flows out with the same bias flow
uses traditional ETT
can use with CV or spontaneously breathing pt
Before placing pt on HFV
get CXR
Give surfactant
Stabilize as much as possible so infant is not needing stimulation when first place on place monitors
After placing on HFV
monitor CO and fluid balance
sedate
Settings HFJV
Start at 7hz
I time 0.2 seconds
PIP at 90% or 10 above PIP on CV
Reduce CV rate and increase PEEP until Mean airway pressure same as CV
May keep min CV rate to maintain CO2 and reduce atelectasis (ie 4bpm)
Setting HFOV
no gradual reduction of CV, just place on HFOV
two strategies
Optimal lung volume strategy (RDS)
-10Hz for > 750 g, 15hz for <750g
Ti 33%
Set mean airway pressure 1-2 higher than on CV, until PaO2 OK
Change in pressure for adequate chest wall movement
check CXR for adequate expansion (diaphragm at 8th or 9th rib)
Adjusting settings HFV
To decrease CO2 increase Amplitude
to increase O2 increase Mean airway pressure (PEEP)
Usually dont adjust Hz
Wean HFV
Wean MAP in increments of 0.5 to 1.0 slowly
wean as long as FiO2 remains under 0.3
Diseases used with HFV
Pulmonary Interstitial Emphysema (PIE)
Pulmonary air embolism (rare)
PIE
Air dissects throughout the interstitial tissue of the lungs
PIE caused by long term use of
HIGH PIP
PEEP
Prolonged Inspiratory time
PIE pathology
Interstitial air compresses small airways and vessels —> V/Q mismatch
Tx of mod to severe PIE
Prevent, decrease pressures, Selective intubation of the unaffected lung, HFV
ECMO/ ECLS
Extracorporeal Membrane Oxygenation
Extracorporeal Life Support
What decreases the amount of ECMO being used
HFV and iNO because the neonates can be managed well with these two therapies
Diagnosis of ECMO
PPHN persistent pulmonary hypertension of newborn MAS (meconium aspiration) RDS Sepsis Congenital Diaphragmetic hernia Air leak Syndromes
PPHN
Pulmonary vascular bed remains constricted due to low O2 content
pressure remain high in the right side of the heart continuing the fetal circulation through the ductus arteriosus and the foreman ovale. thus deoxygenated blood is shunted to the left heart and out to the body
Criteria of ECMO
Oxygen index > 40 on Conventional Ventilation Oxygen Index >60 on HFOV Reversible lung disease Absense of congenital anomalies 32 week gestational age min no major intraventricular hemorrhage
Venoarterial system
blood from right atrium back through aortic arch used to circulate blood through body
Types of ECMO
Venoarterial system
Venovenous system
Venovenous system
blood from and back through right atrium
only oxygenates and removes CO2 does not circulate blood
not as efficient as V-A
ECMO System
Pumps to move blood Membrane oxygenator and CO2 remover Some add hemofilter for hemodialysis circuits need to be primed blood heater before returning to pt cannulas to place in veins and arteries anticoagulation to prevent clotting
Monitoring pt on ECMO
Oxygenation assessed by SvO2 (75%) and/or SpO2 (>90%)
Sedate not paralyzed
Ultrasound of head looking for bleeding
Minimal ventilation: FiO2 21-40% , peak pressures 20-25, PEEP 4-10, RR 5-10
An 27 week gestiational age, 900g, male infant is intubated and given surfactant replacement therapy. The lung compliance is expected to increase rapidly. Which type of mechanical ventialtion would you recommend?
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Indications for HFV
RDS when conventional ventilation fails
Airleaks/pneumothorax
PIE
Calculate Hz
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