Starting Mechanical Ventilation Flashcards
When to move from CPAP to MV
When on CPAP move to mechanical ventilation when
SaO2< 85% at an
FiO2< 40-70%
and PEEP of 5-10 cmH2O
Indications for Mechanical Ventilation in Adults
ASIA
Apnea
Severe Refractory Hypoxemia
Impending ventilatory Failure
Acute Ventilatory Failure
Indications for Mechanical Ventilation in Adults
Severe Refractory Hypoxemia
A-a Gradient (mmHg)
- Normal
- 25-65 On FiO2 1.0
- 5-20 On Room Air
- Critical
- >350 On FiO2 1.0
PF Ratio
- Normal
- 350-450
- Critical
- <200
PaO2/PAO2
- Normal
- 0.75-0.85
- Critical
- <0.15
Indications for Mechanical Ventilation in Adults
Impending Respiratory Failure
Assess WOB and other relevant parameters
MIP (cmH2O)
VC (mL/kg)
Vt (mL/kg)
RR (bpm)
Vd/Vt
MIP (cmH2O)
Normal -80 to -100
Critical 0 to -20
VC (mL/kg)
Normal 65-75
Critical <10
Vt (mL/kg)
Normal 4-8
Critical <4
RR (bpm)
Normal 12-20
Critical >35
Vd/Vt
Normal 0.25-0.4
Critical >0,6
Indications for Mechanical Ventilation in Adults
Acute Ventilatory Failure
PaCO2> 55 mmHg and a pH >7.25
Indications for Mechanical Ventilation in Adults
- Apnea
- Respiratory Failure
- pH < 7.20
- PaO2< 50 mmHg
- PaCO2>65 mmHg
- We will seldom wait for this clinically and instead initiated mechanical ventilation sooner
- Pulmonary Disease
- Neurological and Neuromuscular
- Congenital Abnormalities
- Post Surgery
Classic Indications for Mechanical Ventilation in Infants
- Classic indications of mechanical ventilations in infants with respiratory failure or persistent apnea
- Respiratory Failure
- Arterial blood pH <7.20
- PaCO2 of 60 mmHg
- Oxygen saturation of 85% at oxygen concentration of 40-70% and CPAP of 5-10 cmH2O
Extremely low body weight infants and mechanical ventilation
In extremely low body weight (ELBW) infants (weighing <1000g) intubation and positive pressure ventilation (PPV) may be necessary immediately after birth
Infants with Mechanical Ventilation just admitted to NICU
- Generally once the infant is stabilized in the NICU a pressure limited ventilator using a sinusoidal flow pattern is used. The settings that are commonly used are the following
- If a longer Ti is required before surfactant administration, it should be lowered to 0.3 seconds after surfactant is administered
Infants Mechanical Ventilator Modes
Ventilator modes such as synchronized intermittent mandatory ventilation (SIMV) or assist control modes can reduce WOB and blood pressure fluctuations if the sensitivities are properly set
Modes that maintain a consistent Vt can reduce risk of volutrauma (damage caused by overdistention by mechanical ventilation set for excessively high Vt) particularly after the administration of surfactant
High frequency ventilation may be indicated in infants who cannot be ventilated with the usually effective FiO2 levels, ventilator pressures, and rates
Sponataneous Parameters in Adults
RR (bpm) 12-20
Vt (ml/kg) 4-8
VC (ml/kg) 65-75
Resistance (cmH20/L/sec) 0.6-2.4
Compliance (mL/cmH2) 50-170
Sponataneous Parameters in Neonates
RR (bpm) 30-60
Vt (ml/kg) 5-7
VC (ml/kg) 35
Resistance (cmH20/L/sec) 25-50
Compliance (mL/cmH2) 1-2
What is different between neonates and pediatrics
- Faster RR
- Smaller VC
- Much, much higher airway resistance
- Think of how small the diameter is and this will increase resistance to the 4th power
- Much, much lower compliance
- This is normal
- Preemies will have even worse compliance as they develop RDS
GOALS OF MECHANICAL VENTILATION
Improve oxygenation to meet the metabolic demands of the body
Eliminate CO2
Reduce work of breathing
INITIAL VENTILATOR SETTINGS
Infant
- Peak Inspiratory Pressure should be set to 15-25 cmH2O
- PIP Limit should be set to 30
- Tidal Volume should be set between 3-5 ml/kg
- What about deadspace
- Ex. Flow transducers, ETCO2
- What about deadspace
- Positive End Expiratory Pressure (PEEP) should be set to 3-6 cmH2O
- A proper set PEEP is used to prevent further alveolar collapse
- Increases typically made in increments of 1-2 cmH2O. PEEP may be 8 before alternative modes trialled.
- Respiratory Rate should be set 20-50
- Start at 50
- Used to treat hypercapnia
- Inspiratory time should be set to 0.3-0.4
- Start at 0.3
- Adjust to reach equilibrium
- Mode
- Begin with Pressure Control Volume Targeted Ventilation
- If leak is > 40%
- Consider a larger ETT, extubation to NIPPVS, or A/C PC ventilation
- The trend towards using NeoPuff and/or setting up on ventilator sooner. Goal is to minimize inadvertent inverse ratio and high pressures.
VENTILATORY CHANGE PARAMETERS
*These goals do not apply when CHD or PPHN is present
VLBW (28-40 Weeks)
Goal PaCO2-Emphasize point that regardless of reference it is a permissive hypercapnia strategy overall
- pH
- ≥ 7.25
- PaCO2 (mmHg)
- 45-55
- PaO2 (mmHg)
- 50-70
- HCO3- mmol/L
- 18-20
- SpO2
- 85-92
VENTILATORY CHANGE PARAMETERS
*These goals do not apply when CHD or PPHN is present
ELBW (<28 Weeks)
Goal PaCO2-Emphasize point that regardless of reference it is a permissive hypercapnia strategy overall
- pH
- ≥ 7.25
- PaCO2 (mmHg)
- 45-55
- PaO2 (mmHg)
- 45-65
- HCO3- mmol/L
- 15-18
- SpO2
- 85-92
Initial Setting of Peds Vent
Tidal Volume
6-8 mL/kg
May be as low as 4mL/kg
May be as high as 10 mL/kg
Will depend upon the size of the pediatric population
For testing I say that goal range of VT is same as adults 6-10 ml/kg normally, 5-7 for protective=this makes whole table similar/same as adults!
Remind that if a small pediatrics (e.g. 10 kg) then think closer to neonatal strategies
Initial Setting of Peds Vent
PEEP
Start at 4-5 cmH2O
Aim for optimal PEEP
Increase typically made in increments of 1-2 cmH2O
Watch for CV compromise with increasing PEEP
Optimal PEEP is that which achieves the best lung compliance and oxygenation with the fewest CV side effects
Initial Setting of Peds Vent
Circuit
<25 kg for a neonate
>25 kg Adult
Neo circuit is always heated
Adult circuit will depend upon the size of the pediatric
Initial Setting of Peds Vent
Inspiratory Time
Smaller child 1.0 seconds
Longer for a larger child
Initial Ventilatory Settings for Toddler
- RR (breath/min)
- 20-35
- Vt (ml/kg)
- 5-8
- Inspiratory Time
- 0.6-0.7
- PEEP
- 5
Initial Ventilatory Settings for Small Child
- RR (breath/min)
- 20-30
- Vt (ml/kg)
- 6-9
- Inspiratory Time
- 0.7-0.8
- PEEP
- 5
Initial Ventilatory Settings for Child
- RR (breath/min)
- 18-25
- Vt (ml/kg)
- 7-10
- Inspiratory Time
- 0.8-1
- PEEP
- 5
Initial Ventilatory Settings for Adolescence
- RR (breath/min)
- 12-20
- Vt (ml/kg)
- 7-10
- Inspiratory Time
- 1-1.2
- PEEP
- 5
PEDIATRIC ABG
- pH
- 7.35-7.45
- PaCO2(mmHg)
- 35-45
- PaO2(mmHg)
- 80-100
- *May be less on capillary gas
- HCO3- (mmol/L)
- 22-26
- SpO2
- 95-100%
- Goal is just higher than 90%