Chapter 17 Flashcards
Mechanical ventilation of the neonate and pediatric patient
What are the indications of Mechanical ventilation of the neonate and pediatric patient?
- Hypoxemic respiratory failure
- PaO2 < 50 on an FiO2 > 60% despite the use of CPAP - PaCO2 < 30 and pH > 7.25
- nasal flaring, grunting, retractions - Hypercapnic respiratory failure
- PaCO2 > 50 and pH < 7.25
- apneic, listless, cyanotic, bradycardic or tachycardic - Mixed also possible
- reversible problem exists - Causes
- neurological alteration
- impaired respiratory function
- impaired cardiovascular function post-op
- Pressure ventilation
- Pressure Control Ventilation (PCV)
- Time cycled, pressure limited
- Peak pressure set
- Variable flow
- Set Ti
- Set rate
- PEEP
- No direct control of Vt
- Volume Ventilation
- Traditional ventilation for adults
- 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)
- What are the Triggering, sensors at airway add deadspace and weight?
- Flow
- Pressure
- Motion, detects chest/abdominal movement
- Neural, detects diaphragm signals
- What are the Modes of ventilation?
- Full ventilatory support
- Continuous Mandatory Ventilation (CMV, A/C)
- All breaths are machine breaths, pt triggered or time triggered controls minute ventilation better
- may be pressure or volume breaths
- Volume: set tidal volume and rate
- Pressure: set peak pressure and rate
- PCV used for RDS, plateau pressure >35 or peak >40 - Synchronized Intermittent Mandatory Ventilation (SIMV) Mandatory breaths with spontaneous breaths in-between partial ventilation if rate below 30, full support if over 30 indicated if pt has apnea and needs a machine rate
Mandatory breaths are pressure or volume control ventilation: Spontaneous breaths are basically CPAP or PSV
avoids breath stackingPressure Control Inverse Ratio Ventilation (PCIRV)
- Pressure Control Inverse Ratio Ventilation (PCIRV)
- CMV or SIMV mode
- I time longer than E time
- pt needs to be paralyzed and sedated
- Used to improve oxygentation by raising mean airway pressure (MAP)
Pressure-Volume relationship
- Compliance
- stiff lungs cause low volumes with pressure ventilation
- Compliance curves
- volume pressure relationship
stiff lungs cause less volume with same pressures
over compliant lungs cause more volume with same pressures S shaped curve, see page 485
- volume pressure relationship
-Normal point B, good increase in volume with increase pressure Stiff point A, very little volume increase with pressure increase Overinflated lungs point C, little or no volume change with pressure
change
-Keep PEEP at inflection point, point A
do not use pressures that do not generate volume
- What are the Pressure-Volume relationship
- Compliance
- stiff lungs cause low volumes with pressure ventilation
- Compliance curves
- volume pressure relationship
stiff lungs cause less volume with same pressures
over compliant lungs cause more volume with same pressures S shaped curve, see page 485
- volume pressure relationship
-Normal point B, good increase in volume with increase pressure Stiff point A, very little volume increase with pressure increase Overinflated lungs point C, little or no volume change with pressure
change
-Keep PEEP at inflection point, point A
do not use pressures that do not generate volume
- What are the Pressure-Flow relationship?
- Not usually measured
but increase in Raw will decrease Vt factors that cause increased Raw
- bronchospasm (bronchodilator)
- Airway secretions (suction)
- Edema of airway walls (fluid balance)
- Inflammation (antibiotics, antiinflammatory) Artificial airway (Use largest possible)
- Setting the ventilator
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 ventilation if no relief with above
(Other things to be done, surfactant replacement therapy, NO administration,
ECMO)
- Mode (pediatric)
- Much like adult only smaller Vt (6-8 ml/kg)
- 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 15-20 cmH2O
2. pediatric set to achieve desired Vt (see below)
- vSee table 17-2, page 313 for RR, Vt Ti, PEEP, FiO2 starting settings
- Rate
- neonate: start 40-60
- term: start 25-40
- pediatric: set to achieve desired CO2
- PEEP starts where?
- Start 5 cmH2O
- FiO2
- neonate: keep baby pink, use TCM or P-ox to keep within normal limits
- pediatric: PaO2 and/or SpO2 normal limits, 100% if needed for short times
- Where to start Inspiratory Time
- Low birth weight infants: 0.25 to 0.4
- Term infants: 0.3 - 0.5
- Pediatric: 0.6-1.2
- Comfort level also
- Where to start Tidal Volume
- Pressure control: result of pressure, airway resistance, and lung compliance
- Low birth weight 4-6 ml/kg
- Term5-8 ml/kg
- Pediatric 6-8 ml/kg
- I:E ratio
1:1.5 to 1:2
always check ratio when changing rate