initial PIP for neonatal mechanical ventilation:
15-20 cmH20
initial tidal volume for neonatal ventilation:
4-6 ml/kg
how should FiO2 be
... [Show More] set for infants?
titrate to maintain lowest required PaO2 and SpO2 for gestational age (PaO2 >50 mmHg)
what rate should infant ventilator be set at?
30-60 bpm (adjust to maintain PaCo2 and pH
infant flow rate:
6-10 L/m
infant itime:
.35-.45 seconds (keep ratio 1:1)
normal newborn breathes with an I:E ratio of:
1:1.5 to 1:2
What happens to I time when flow rate is increased
Shorter itime
Increased cpap causes better oxygenation by increasing what?
MAP
What can too much peep cause
May impede ventilation and increase co2
What will an increase in PiP result in
Larger tidal volumes and better ventilation
What will a slower flow rate result in
Increased itime
What can contribute to an unstable FRC in neonates
Increased airway closure, impaired gas exchange, low lung compliance, high resistance , compliant chest wall
Stiff lungs
Prone to collapse even in absence of disease
Describe how correctly sized nasal prongs fit a neonate
They completely fill the lumen of the nares without stretching them
What is the ultimate goal of mechanical ventilation
Support the patient until the underlying problem is resolved
What are the goals of NcPAP NIV and NIPPV
Maintain adequate pulmonary gas exchange
Optimize comfort
Reduce WOB
Do no harm
What things contribute to fragile neonatal pulmonary lung mechanics
Immature respiratory control center
Small size of airways
Incomplete alveolarisation
Immature surfactant production
No collaterals pathways of ventilation until age 3-4
Unstable FRC and chest wall
Small muscle mass
What is the metabolic rate of neonates
7 ml/kg/min (2x as much as adults)
How does the high metabolism of neonates effect O2 consumption
There is less reserve if O2 consumption needs are increased due to critical illness
What might a very low birth weight preterm infant pH goal be
7.25
65
Sao2 greater than 86%
For lung protection
A persistent pulmonary hypertension patient would have what mechanical ventilation goals
Ph great than 7.45
Co2 less than 30
Pao2 of 100
Goal is pulmonary vasodilation
List methods used to prevent lung injury
Avoidance of mechanical ventilation (use NIV)
Permissive hypercapnia
Surfactant replacement
Optimization of lung volume/avoidance of atelectasis
Limit exposure to high fio2
Avoid excess Vt
Volume targeted ventilation
High frequency ventilation
What changes should be considered for elevated PaCO2?
Verify et tube position and patency
Increase rate by increments of 5-10 bpm
Increase PIP by increments of 2 cm h2O to achieve chest expansion and tidal volume
Ensure sufficient etime
Reduce peep if lungs are hyper inflated
Consider sedative or muscle relaxant with MD
Transilluminate, rule out pneumothorax
What changes should be considered for a reduced PaO2
Verify ET tube position and patency and validate ABG
Increase fio2 3-5% at a time to required fio2
Increase itime to .4-.6 seconds, maintain I:E greater than 1:1
Increase peep to achieve higher Paw
Increase PiP to deliver optimal tidal volume
When units fill and empty rapidly and compliance is low, the time constant will be (short/long)
Short
A patient with a short time constant would require what kind of settings
High rate low tidal volume
the lung units fill and empty slowly when there is increased _________
resistance
if resistance is high and compliance is normal the time constant will be (long/short)
long
how will you adjust the rate for a patient with a long time constant
may need to set a low rate to allow sufficient time to completely inflate and deflate lung
how do you calculate time constant
TC = Resistance x Compliance
in a patient with a time constant of .25 sec, _______% of passive exhalation or inhalation occurs in 0.25 sec
63%
resistance is _______ and compliance is ________ the time constant will be short.
normal
poor
resistance is ______ and compliance is ________ the time constant will be long.
high
normal
how many time constants results in 95% filling and emptying in normal lungs
3 time constants
inspiratory time constant of less than 3 may result in:
incomplete delivery of tidal volume
how would you resolve incomplete delivery of Vt?
prolong the itime
what is indicated if the expiratory flow waveform is short and steep
the patient has a short time constant
what is auto peep
incomplete emptying of the lung before the ventilator gives the next breath
what are 2 techniques for minimizing auto-peep
decrease airflow obstruction
modify the ventilation pattern
what steps can be taken to decrease airflow obstruction in an effort to minimize auto-peep
suction to remove scretions
bronchodilation
possible steroids for mucosal edema
how can you modify the ventilation pattern in an effort to minimize auto-peep?
extend exp. time (if all airway clearance has already been done)
recommend narcotics to decrease pts respiratory drive and slow the respiratory rate
(not always appropriate to decrease I-time)
patient-ventilator interaction is the relationship between what 2 respiratory pumps?
patients pulmonary system
ventilator
what are the 4 phases of a breath
1) trigger mechanism
2) inspiratory-flow phase
3) breath termination
4) expiratory phase
what type of patients are particularly prone to developing auto peep?
patients with obstructive lung disease
what influences the triggering of a breath?
trigger sensitivity setting
patient effort
valve responsiveness
PTP (pressure time product)
What factors make for the most limitation with neonatal ventilation?
presence of leaks and uncuffed tubes
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