Module 2: Invasive Respiratory Support Flashcards
1
Q
What is Ventilation vs Respiration?
A
- Ventilation is movement of gases in and out of the pulmonary system,
- Respiration involves the exchange of oxygen and carbon dioxide at the alveolar-capillary level and at the capillary-cellular level
***Respiration is the process of gas exchange throughout the body- a much larger and more complex process
2
Q
What is ventilation compromised of (2)?
A
- pulmonary ventilation
- alveolar ventilation
3
Q
What is pulmonary ventilation vs alveolar ventilation?
A
- Pulmonary ventilation is the volume of air exchanged between the environment and the lungs.
- Alveolar ventilation is the volume of air entering the alveoli that takes part in gas exchange per minute (This takes place across the alveolar-capillary membrane)
4
Q
What are 3 bodily functions that ventilation is maintained by?
A
- central nervous system: located in the medulla oblongata (brain stem)
- stretch reflexes: located in chest wall and airways (serve to alter breathing pattern to maintain adequate minute ventilation)
- chemoreceptors: located in the aorta and carotid artery (respond to increases and decreases on PaO2, PCO2 and pH
5
Q
How does increase or decrease in pO2 and pCO2 affect minute ventilation?
A
- Minute Ventilation: the product of Rate X Volume
- ↑pCO2 will lead to increased minute ventilation.
- ↓pCO2 will lead to decreased minute ventilation.
- ↓pO2 leads to increased minute ventilation.
6
Q
What is functional residual capacity (FRC)?
A
- Normal alveolar ventilation occurs when an infant has a sufficient respiratory drive and sufficient energy to inflate and deflate the lungs, maintaining some volume at the end of every breath known as the functional residual capacity
- FRC is maintained when sufficient surfactant minimizes surface tension (tendency for alveoli to collapse) and the alveoli remain slightly open at the end of each exhalation
7
Q
What are some reasons as to why preterm infants are at risk of pulmonary compromise due to their immature pulmonary system (4)?
A
- ↓ surfactant
- ↓ alveoli
- ↓ capillaries
- ↑ distance between alveoli and capillaries
- Small airways
- Underdeveloped, weak muscles
- Underdeveloped pulmonary vasculature
- Cartilaginous rib cage
8
Q
How does mechanical ventilation assist with ventilation?
A
- by delivering air and oxygen to the lungs, but gas exchange or respiration must still occur at the alveolar and cellular level
9
Q
What is the difference of ventilation and respiration?
A
- Ventilation is the act of inhalation and exhalation for the purpose of gas exchange within the lungs.
- Respiration is the gas exchange that occurs at a cellular level (It allows the exchange of gas such as O2 and CO2 between an individual and his or her environment)
10
Q
What is respiration dependent on (5)?
A
- Sufficient alveolar ventilation
- Alveolar/capillary diffusion
- Pulmonary perfusion
- Hemoglobin
- Peripheral perfusion
11
Q
Where are the two places that gas is exchanged?
A
- in the lungs
- tissues (at the cellular level)
12
Q
Where does alveolar respiration and cellular respiration take place?
A
- Alveolar respiration occurs in the lungs;
- cellular respiration occurs in the tissues.
13
Q
For respiration, what is the role of the cardiovascular system? brain?
A
- The cardiovascular system acts as a conduit between these two sites of gas exchange.
- The brain acts as a central controller
14
Q
If the entire process of respiration occur in all body cells, what are the three main system that are responsible for gas exchange?
A
- pulmonary system
- circulatory system
- nervous system.
15
Q
What are the 3 interdependent processes that is a result of alveolar respiration?
A
- alveolar ventilation
- pulmonary perfusion
- diffusion across the alveolar-capillary membrane to allow for pulmonary perfusion
**Alveolar respiration: gas exchange that occurs between the alveoli and the pulmonary capillaries in the lungs
16
Q
How does diffusion across alveolar-capillary membrane occur?
A
- because of pressure gradients for oxygen and carbon dioxide
- these gases move from areas of high pressure toward areas of low pressure.
- oxygen moves from the alveoli to the capillaries
- carbon dioxide moves from the capillaries to the alveoli.
17
Q
How does CO2 diffuse across the alveolar-capillary membrane differently from O2?
A
- CO2 is much more diffusible than O2.
- Even with diminished perfusion, CO2 diffuses readily from pulmonary venous and capillary blood to the alveoli.
- Once in the alveoli, CO2 is dependent on adequate alveolar or minute ventilation for elimination.
18
Q
Which gas is the primary indicator of adequate alveolar ventilation?
A
- CO2
- Changes in carbon dioxide levels are primarily due to changes in minute ventilation.
- Elevated CO2 indicates hypoventilation;
- CO2 depletion indicates hyperventilation .
19
Q
What type of breathing patten when theres diminished tidal volume and/or decreased rate?
A
- Hypoventilation is the term used to describe a breathing pattern that results in decreased minute ventilation
20
Q
What can cause hypoventilation in infants (3)?
A
- prematurity of the lungs which may include RDS.
- CNS depression,
- BPD,
- MAS,
- pneumonia,
- apnea of prematurity, and
- diaphragmatic hernia.
21
Q
What can happen due to lack of surfactant?
A
Due to the lack of surfactant in the immature lungs,
- compliance decreases,
- the work of breathing increases,
- tidal volume decreases.
Initially, in an attempt to maintain minute ventilation,
- an infant responds with tachypnea.
However, premature infants will quickly tire
- tachypnea will become bradypnea and apnea.
Thus, hypoventilation will occur.
- Minute ventilation falls.
- Indrawing will become evident.
- Pallor and/or cyanosis may appear.
- The infant may grunt in an attempt to prematurely close the glottis and maintain FRC
22
Q
Whats pulmonary perfusion?
A
- refers to the flow of blood through the portion of the circulatory system that supplies the lungs
- De-oxygenated blood travels from the right side of the heart through the pulmonary arteries to the lungs where oxygen will be picked up and returned to the left heart side of the heart through the pulmonary veins.
- The oxygenated blood can then travel out the aorta and to the rest of the body.
- At the same time, the blood transported to the lungs by the pulmonary artery will deliver CO2 picked up from the tissues and carry it back to the lungs for elimination.
23
Q
What are 2 things that pulmonary perfusion dependent?
A
- oxygen and pH of blood
in response to concentration of hypoxia and acidosis:
- the pulmonary vasculature will constrict (increased pulmonary vascular resistance [PVR]), leading to diminished pulmonary perfusion.
- This will resulting the development of pulmonary hypertension.
24
Q
What are 3 important respiratory processes occur in lungs?
A
- ventilation,
- diffusion and
- perfusion
25
What is the circulatory system responsible for?
- circulatory system acts as a courier, transporting gases between tissues and the lungs.
- It is responsible for delivering oxygen from the lungs to the cells and carbon dioxide from the cells to the lungs.
- The heart is the pump
- the vasculature (vascular system made up of vessels) is the conduit
26
What is cardiac output?
- Cardiac output is the volume of blood pumped by the heart in one minute, (mls/min).
- Cardiac output is a product of heart rate × stroke volume.
**Stroke volume is the volume of blood pumped with each beat (mL/beat).
27
Stroke volume is a product of what 3 factors?
- preload: refers to the volume of blood in the ventricles prior to contraction (diastolic).
- afterload: refers to the pressure or resistance against which the ventricles are pumping (systolic blood pressure)
- contractility: refers to the strength of contraction of the heart muscle
28
What are the 3 ways CO2 is transported?
- dissolved in plasma
- attached to hemoglobin
- combined with H20 to form H2CO3 (carbonic acid)
***Most CO2 is dissolved in plasma or as carbonic acid; very little is carried by hemoglobin.
29
What are 2 ways oxygen is transported?
- dissolved in plasma (2%)
- attached to hemoglobin (98%)
30
What needs to reach capillary beds for cellular respiration to occur?
- Once arterial blood (containing oxygen and CO2) reaches capillary beds in the tissues
31
What are the two types of chemoreceptors that control respiration?
Central Chemoreceptors:
- located in the brain stem and
- respond to the acidity of the CSF
- involved in control of respiratory rate and depth of breath
Peripheral Chemoreceptors
- located in the aortic arch and carotid arteries
- respond to changes in oxygen concentrations, CO2 and pH
- regulate breathing breath to breath
32
CNS depression and damage can lead to what (3)?
respiratory problems such as
- bradypnea,
- bradycardia,
- apnea,
- hypoventilation,
- hyperventilation, and
- hypotension.
33
What is the difference between ventilation and respiration?
- Ventilation is the movement of gases in and out of the lungs
- respiration is the gas exchange of oxygen and carbon dioxide at the alveolar-capillary level and at the cellular-capillary level.
34
What 4 physiological factors is respiration dependent on?
- Sufficient alveolar ventilation,
- pulmonary perfusion,
- hemoglobin,
- peripheral perfusion.
35
Describe ways in which the pulmonary, circulatory, and nervous systems work to maintain respiratory function
Pulmonary system:
- Pulmonary ventilation,
- pulmonary perfusion,
- diffusion across the alveolar-capillary membrane to allow for pulmonary perfusion.
Circulatory system:
- By maintaining cardiac output (HRxSV).
- SV is a product of preload, afterload, and contractility.
- CO2 is also transported via dissolved plasma, attached to hemoglobin, and/or combined with H20 to form H2C03 (carbonic acid).
- Oxygen is transported via dissolved plasma and attached to hemoglobin.
Nervous system:
- Central and peripheral chemoreceptors.
- Central receptors are located in the brain stem and respond to acidity in the CSF.
- They control the rate and depth of breath.
- Peripheral receptors are located in the aortic arch and carotid arteries and respond to changes in oxygen concentration, carbon dioxide and pH.
- Peripheral receptors regulate breathing on a breath to breath basis.
36
What is the primary goal of mechanical ventilation?
Primary goal of mechanical respiration:
- to improve minute ventilation and oxygenation
Desired outcomes of mechanical ventilation:
- to achieve and maintain adequate pulmonary gas exchange
- to minimize the risk of lung injury
- to reduce patient work of breathing (WOB)
- to optimize patient comfort
- to improve oxygenation
37
What are some desired outcomes of mechanical ventilation (4)?
- to achieve and maintain adequate pulmonary gas exchange
- to minimize the risk of lung injury
- to reduce patient work of breathing (WOB)
- to optimize patient comfort
- to improve oxygenation
38
What is mechanical ventilation?
- the application of positive inspiratory pressure to inflate the lungs.
39
What is mean airway pressure?
- the amount of pressure exerted on the airway during an entire respiratory cycle.
- An increased mean airway pressure allow for recruitment of collapsed alveoli and/or redistribution of lung fluid to decrease dead space ventilation (an area of ventilation in absence of perfusion), and shunting (an area of normal perfusion but absent of ventilation).
40
How is newborn lungs much like a balloon?
- Once a balloon has been inflated, it is generally easier to inflate it again because of the structural changes to the balloon wall.
- Similarly, once the structure of the airway wall is compromised by mechanical ventilation, it will behave differently when subsequent pressure is applied.
- Although the lungs may recoil to its original shape after the exhalation of each breath, some elasticity will be lost over time and the lungs will loose structure and become larger than normal.
41
What is compliance?
- is the change in volume over the change in pressure.
**We consider both the lungs and the chest wall, when referring to compliance.
- compliance: as the amount of effort or ease needed to stretch the lungs and chest wall.
42
What is elasticity?
- is equal to the change in pressure over the change in volume (is the opposite of compliance)
**We also consider elasticity in the context of the lungs and chest wall
- elasticity is the amount of resistance to the stretching.
43
What are 2 ways to prevent further lung injury from mechanical ventilation?
- reducing the infant’s work of breathing and
- by optimizing their comfort.
44
What are 6 signs of increased WOB?
- tachypnea,
- tachycardia,
- indrawing,
- nasal flaring,
- grunting or
- decreased or absent respiratory drive
45
How will mechanical ventilation aimed at decreasing WOB (2)?
- setting the appropriate tidal volume, respiratory rate with the option of pressure support to achieve required alveolar ventilation
- using positive end-expiratory pressure to maintain FRC and thereby improve compliance and expansion of the lungs
46
What is fighting the ventilator?
- referred to as asynchrony
- occurs as the neonate attempts to maintain their own respiratory pattern,
- which may be out of sync with what the ventilator is set to deliver
47
Why is supporting infant to breathe the utmost importance?
- not only for their survival, but as a comfort measure as well.
- These vulnerable infants need to be utilizing their reserves for growth - not using their energy to breathe
48
What are strategies to optimize infant comfort (3)?
- Ensuring the most synchronous mode of ventilation is being utilized
- Non-pharmacologic measures (e.g. Developmentally supportive care)
- Facilitated tucking
- Skin-to-skin
- Nesting
- Noise reduction
- Pharmacologic sedation/pain control
49
What is positive pressure ventilation (PPV)?
- when air is moved into the patient's lungs via an endotracheal tube, tracheostomy tube or mask/prongs interface to create a positive pressure to inflate the lungs
50
Is mechanical ventilation like normal breathing?
no
51
What are the twos ways that mechanical ventilation is different from normal breathing?
- The positive pressure needed to inflate the lungs with mechanical ventilation is much greater than the negative pressure needed with normal breathing.
- Mechanical ventilation bypasses the normal internal biochemical feedback mechanism that controls breathing.
52
How is our normal breathing like a vaccum?
- when we inhale, our lungs expand as a result of negative intrathoracic and intrapleural pressure.
- This negative pressure actually pulls the lungs open from the outside - much the way a vacuum bag is expanded inside the vacuum chamber of a vacuum cleaner.
- As a result, the pressure within the lungs does not increase significantly as the lungs inflate.
53
How does mechanical ventilation work (how is it like blowing up a balloon)?
- mechanical ventilation uses high positive pressure exerted on the inside of the airways and lungs to push them open from the inside - much like blowing up a balloon.
- As a result, the pressure within the lungs increases significantly as the lungs inflate.
- In fact, without this significant increase in pressure, the lungs would not inflate
54
What are some problems with using positive pressure to inflate an infants lungs?
- is that this pressure causes damage to fragile and developing lung tissue
- Edema, inflammation, scarring, over-inflation, and loss of elasticity are a few of the more common and more serious problems that result from the barotrauma, (damage due to pressure) caused by positive pressure ventilation, and
- volutrauma, (damage due to over-distension of the lung).
55
What is the difference of barotrauma vs volutrauma?
- barotrauma: damage due to pressure caused by positive pressure ventilation, and
- volutrauma: damage due to over-distension of the lung
56
What is the difference between pressure and volume?
Pressure refers to force
- in mechanical ventilation, pressure refers to the force being applied to the inside of the alveoli as they are being inflated.
- Think about blowing up a balloon.
- Pressure is the force you use to inflate the balloon.
Volume refers to the space something occupies.
- For example, in ventilation, volume refers to the amount of gas inside the alveoli.
- Think about the balloon you have just used force to inflate.
- Volume refers to the amount of gas inside the balloon after it is inflated.
**greater pressure you apply to inflate the lung, the greater the volume you will achieve
57
What are the two forces that impose the inflation of the lungs?
- compliance (Litres/cmH2O)
- resistance (cmH2O/Litres/second)
58
What is compliance?
- How compliant a baby’s lungs are affects how much volume moves into a lung at a given pressure.
- It affects how much pressure is required to achieve a given end-inflation volume within a lung.
Think about two balloons:
- One is slightly inflated and the other is collapsed.
- It takes less pressure to inflate the first balloon because it is more compliant.
- It would take more pressure to achieve the same volume in the collapsed balloon because it requires more pressure to inflate, and is therefore less compliant.
59
What is resistance?
- Resistance is the measurement of the frictional forces that must be overcome during breathing.
Examples of an increase in force can be
- a result of anatomical structures of the airways,
- decrease diameter of the endotracheal tube size,
- increase in secretions,
- bronchospasm,
- mucosal edema
** An increase in resistance will require more pressure to achieve the same end-inflation volume within a lung.
60
What is pressure ventilation?
- is a continuous flow, time cycled and pressure limited mode that provides a constant pressure at the airways
- It allows the respiratory therapist to set a desired pressure limit, inspiratory time and rate
**Normal inspiratory times for infants range from 0.3 seconds to 0.55 seconds
61
What is the range PIP is used for mechanical ventilation?
- Normal pressures used to mechanically ventilate infants using a pressure ventilator range from a peak inspiratory pressure (PIP) 12 cm H2O to 40 cm H2O,
- however <25 cm H2O is preferred because levels higher than this places the infant at risk for lung damage and air leaks
62
How do health care providers decided what pressures will achieve normal tidal volumes for a particular infant (4)?
by selecting peak inspiratory pressures which:
- Produce normal chest movements (adequate bilateral chest rise)
- Normalize pCO2, pH, and PaO2
- Within the 12-40 cm H2O range
- Capable of delivering adequate tidal volumes (3-7 ml/kg)
63
What is volume guarantee (VG)?
- a setting on the ventilator within pressure controlled ventilation.
- VG on the ventilator is designed to deliver tidal volumes most appropriate for adequate gas exchange
64
What is tidal volume?
- is the volume of gas inhaled or exhaled during a normal breath
- When the tidal volume and/or the inspiration time for that breath have been reached, inspiration ends.
** The ventilator will use the least amount of pressure to deliver this tidal volume based on a breath to breath analysis of previous pressures needed to achieve the set volume.
65
Will ventilators with volume guarantee limit pressure in anyway?
- yes
- Recall that normal tidal volume for an infant is 3-7 ml/kg.
- A 2 kg infant would likely require a tidal volume of 5 ml/kg = 10 ml.
What amount of pressure is required to deliver this tidal volume?
- That would depend on the compliance and resistance of the infant’s lung.
- If the infant’s lungs are very compliant, low pressures would be required.
- If they are stiff and noncompliant, higher pressures would be required.
- If however, this infant’s lungs are so stiff that very high pressures would be needed to reach 10 ml of volume; there is a safety feature that prevents this from happening.
- This safety feature is called a pressure limit.
- A pressure limit is normally set to not exceed approximately 25 cm H20.
- Recall that high inspiratory pressures contribute to the barotrauma that infant’s lungs experience as a result of mechanical ventilation.
66
What does increased resistance lead to?
- lead to increased pressures necessary for reaching preset tidal volumes.
Examples of causes for increased resistance would:
- be kinked ventilator tubing,
- a blocked ET tube, or
- an increase in secretions to mention a few.
**In these cases, the pressure limits would be reached before the tidal volume was reached.
67
How does volume ventilation provide target tidal volumes with each breath?
- volume ventilation does this using the pressures needed based on compliance and resistance.
- Pressure limits are set to prevent the infant from receiving extremely high pressures.
- With volume ventilation, inspiration ends when the tidal volume and/or inspiratory time have been reached.
68
What is the major difference between pressure and volume breaths?
- is the way in which inspiratory gas flow is delivered to the infant
- In both time-cycled pressure-limited ventilation and pressure-control ventilation there is a rapid acceleration of gas flow at the onset of inspiration, resulting in rapid pressurization of the ventilatory circuit and the achievement of peak pressure and volume delivery early in inspiration”
- Flow then decreases. This creates a peaked flow waveform and rapidly rising and falling pressure waveform.
- Therefore, breaths may be considered as being “front-end loaded.”
69
What is mode of ventilation determined by?
- by the breath type (pressure control versus volume control)
- the pattern (minute ventilation [MV] = tidal volume [Vt] x respiratory rate [RR]) in which the breath is delivered
70
What are 3 factors that make up mode of ventilation?
- the targeted control variable (pressure vs. volume),
- whether the breath is mandatory, assisted, or spontaneous,
- the timing of the delivered breath (for instance, is it continuous, intermittent or spontaneous).
71
What is controlled ventilation?
- breaths (pressure or volume) are delivered by the ventilator at pre-set intervals based on respiratory rate, tidal volume, and inspiratory flow rate.
- In between these controlled breaths, the infant cannot take any of his/her own breaths.
- The ventilator is in complete control of every breath.
For example,
- if the ventilator is set to deliver 20 breaths per minute (bpm),
- it would initiate inspiration every 3 seconds (60 sec/min ÷ 20 breath/min = 3 sec/breath).
- No other breaths are possible.
- In other words, the infant cannot “over breathe” the ventilator.
Controlled Mandatory ventilation is often used
- with paralyzed patients or
- patients with no drive to breath.
patients with a poor respiratory drive to breath such as
- apnea of prematurity,
- neuromuscular disorders, or
- sedated patients
72
What is assist ventilation?
- the infant can initiate a pressure or volume breath by making some inspiratory effort.
- The ventilator then responds by delivering a breath at the same parameters as a mandatory breath.
This method works well for infants:
- who are alert with a normal respiratory drive, but who are not able to ventilate effectively because of lung disease.
73
What is assist-control ventilation?
- Assist-control ventilation is a combination of the first two modes - control and assist.
- In this mode initiation of the breath can either be patient triggered or time triggered.
- A breath rate, sensitivity to patient effort, and type of breath (volume or pressure) are set.
- The patient can breathe faster than the preset breath rate but the set volume or pressure will be delivered with each breath.
- The infant is able to self-regulate by adjusting their respiratory rate as their respiratory status improves and therefore reducing barotrauma.
This mode works well in infants
- who have a strong respiratory drive and are not heavily sedated but need help overcoming the compliance and resistance of their lung pathology.
74
What is assist control-volume guarantee (AC-VG)?
- delivers a guaranteed tidal volume with each breath using the least amount of pressure, based on a breath to breath analysis.
- The infant is able to trigger the ventilator to deliver the breath.
- The breath delivered will be targeted on the tidal volume (Vt), inspiratory time (Ti) and pressure used to deliver previous breaths.
- A constant flow will deliver the Vt with the least amount of pressure to overcome the lungs compliance and resistance.
- Should the patient not trigger the ventilator, the ventilator will deliver a mandatory breath based on the set respiratory rate and Vt to maintain the desired minute ventilation.
75
What is intermittent mandatory ventilation (IMV)?
- Intermittent Mandatory Ventilation is similar to the control ventilation, with one important difference.
- Between the ventilator controlled breaths the infant is free to breathe on his/her own.
- This is often referred to as over riding the ventilator.
For example,
- a predetermined rate of 30 could be set and the ventilator would deliver 30 evenly spaced breaths per minute, initiating inspiration every 2 seconds.
- Recall that inspiratory times range from 0.3 to 0.55 sec.
- This means that at a rate of 30 and an I time of 0.3, every IMV breath leaves 1.7 seconds during which the infant can exhale and then take additional breaths from the ventilator circuit.
- However, if the baby does not want a breath every 0.3 seconds (perhaps they just took their own breath), they will receive a breath regardless.
- You can imagine how uncomfortable this mode may be for the infant with a strong respiratory drive.
- This discomfort arises when a ventilatory breath is given out of sync with with infants own respiratory effort.
- Synchronized intermittent mandatory ventilation (SIMV) is thought to limit these adverse effects.
76
What is Synchronized Intermittent Mandatory Ventilation (SIMV)?
- Synchronized Intermittent Mandatory Ventilation (SIMV) is similar to IMV in that
- a mandatory predetermined rate is selected, creating a window of time in which the infant must take a breath with the intent to synchronize the ventilator with the infant's spontaneous respiratory rate.
- When the ventilator senses the infant's effort it will assist the infant on inspiration with a pressure supported breath.
- If no effort is sensed within the window of time a mandatory breath will be delivered.
- Mandatory breaths will continue until a spontaneous effort is sensed again.
77
What is pressure support ventilation (PSV)?
- Pressure Support Ventilation (PSV) can be used in patients with a good respiratory drive.
- PSV is a method of ventilation where the patient controls the breathing rate and inspiration time.
- The patient must be able to trigger each breath.
- The ventilator “supports” spontaneous breathing up to a preset pressure and inspiratory time to help support adequate volume.
- Pressure support ventilation is a common weaning mode of ventilation.
78
What is Neurally Adjusted Ventilatory Assist (NAVA)?
- Neurally adjusted ventilatory assist (NAVA) uses the electrical activity of the diaphragm, (Edi signal), as a neural trigger to synchronize mechanical ventilator breaths with the patient’s neural respiratory drive.
- Remember that a respiratory signal will be sent from your brain stem to the phrenic nerve of your diaphragm stimulating your diaphragm to contract.
- Contraction of your diaphragm will result in the expansion of your chest muscles creating a negative pressure within your lungs.
- This negative pressure will draw air into your lungs. In summary, the ventilator will use this electrical signal to synchronize with the ventilator with the patient’s instantaneous drive to breathe on a breath to breath basis.
- To do this, a specially designed nasal gastric tube with specialized sensors will be inserted into the infant.
- These sensors will detect the electrical activity of the diaphragm to control the timing and pressure delivered during ventilation.
- This mode of ventilation has been shown to better synchronize with the infant, and prevent the infant from needing more sedation in comparison to other modes of ventilation such as PRVC or AC VG.
- Some other benefits of this mode of ventilation is that it is not affected by air leaks or secretions so there is less chance of auto-cycling the ventilator, resulting in hypoventilation.
79
What is High Frequency Ventilation (HFV)?
- attempts to minimize ventilator-induced injury by using volumes that are smaller than the lung’s physiologic dead space (1-2 ml/kg), at very fast breathing rates.
- It is defined as “mechanical ventilation using tidal volumes less than or equal to the dead space volume of the lung and delivered at supraphysiologic rates.
- HFV devices are those that provide breathing rates greater than 150 breaths per minute”
**high frequency oscillatory ventilation (HFOV) and high frequency jet ventilation (HFJV).
80
What is High Frequency Oscillatory Ventilation?
- HFOV is a type of mechanical ventilation that uses small tidal volumes equal to or smaller than the anatomical dead space in the lungs.
- These volumes are set at a very high rate with a constant pressure in the background to maintain lung expansion.
- It is the active exhalation phase that differentiates this mode of HFOV from other high frequency modes .
81
What are the benefits of HFOV (3)?
- Uses smaller tidal volumes
- Higher respiratory rates
- Lower distal airway pressures
- Preservation of lung tissue
- Minimizes barotrauma
82
What are the HFOV settings?
- MAP/Paw: the continuous pressure that is used to inflate the lung and optimize the alveolar surface area for gas exchange to occur. Often chest xrays and oxygen requirements will be used to evaluate if the MAP is appropriate.
- Amplitude (∆P/delta P): is the size of the oscillation and is determined by the change in pressure above and below the set MAP pressure. It displaces a small volume on top of the volume already obtained from the setting of the MAP. The total volume displaced is directly proportional to the change in pressure from the MAP to the peak of the oscillation. i.e. the peak pressure to trough pressure difference. The greater the distance, the greater the volume displaced. The starting amplitude, is chosen by looking at the shake of the infants chest movement and other factors as explained above. The greater the amplitude, the greater the shake, the greater the volume displaced.
- Hertz (Hz): the frequency of oscillations. Increasing the frequency reduces the time available to transmit oscillations (amplitude) to the airways, resulting in a reduced tidal volume. Therefore an increase in Hz results in less CO2 removal due to less displacement in tidal volume. The lower the frequency, the greater the volume displaced, and the higher the frequency, the smaller the volume displaced. 1Hz = 60 breaths/sec.; therefore a Hz of 10 is equal to 600 breaths/sec., RR).
- I:E ratio: this is the ratio of inspiratory time to expiatory time for each breathe the ventilator delivers. It is always set at 1:2.
- Inspiratory Time (Ti): this is how long it takes the ventilator to deliver the tidal volume into the lung.
- Flow: commonly 20 LPM, but this will be variable depending on what ventilator you are working with.
83
When can HFOV be use?
- Extremely premature infants: RDS, BPD
- air leak: PIE, pneumothorax
- Pneumonia
- Meconium Aspiration
- Conventional mechanical ventilation (CMV) causes excessive distention of airways.
- conventional mechanical ventilation is sometimes inadequate/maxed out
Carbon dioxide retention and oxygenation failure
84
What is High Frequency Jet Ventilation (HFJV)?
- High frequency jet ventilation (HFJV) is used in conjunction with a conventional ventilator.
- The conventional ventilator is primarily used for oxygenation.
- The conventional ventilator will deliver the peep, a continuous flow of gas from which the infant can breathe spontaneously, and allow the setting of intermittent sighs in order to help with lung recruitment.
- The conventional ventilator will either be set in the CPAP mode or CMV mode depending on the need for recruitment.
**The jet ventilator is primarily responsible for CO2 removal
85
What are the indications for use of HFJV?
- Premature infants with RDS
- PIE (pulmonary interstitial emphysema)
- Meconium aspiration
- Pneumonias
- CDH (Congenital diaphragmatic hernia)
- PPHN
86
What are the settings on the jet ventilator?
The jet ventilator is a pressure-limited, time-cycled ventilator. The following parameters are set on the jet ventilator:
- PIP
- Ti
- RR
Measured values of the jet ventilator include:
- PIP
- PEEP
- MAP/Paw
- Delta P
- Servo pressure
87
What is servo Pressure?
- is a feedback system on the jet ventilator that tells you whether the ventilator has had to increase or decrease its flow of gas in order to maintain the set PIP.
- The servo pressure changes as perceived lung volume changes, automatically adjusting the flows or driving pressure to maintain the PIP.
- An increase in the servo pressure indicates an increase in the achieved lung volumes;
- a decrease in the servo pressure indicates decreased lung volumes
88
What is the main difference between volume ventilation and pressure ventilation?
Volume ventilation delivers a set tidal volume:
- Inspiration ends when a certain time has elapsed (I time) and a certain Vt hTV has been delivered.
Pressure ventilation delivers a set pressure.
- Inspiration ends when a certain time has elapsed (I time) and a certain pressure has been achieved.
89
What is the main limitation of pressure ventilation?
- The main limitation of pressure ventilation is that when pressure is a constant, pre-set parameter, volume varies as compliance and resistance varies.
- Infants end up both over and underventilated.
90
The main purpose of setting a MAP in HFV is for:
improving oxygenation
91
What are 3 ways to increase the removal of CO2 in HFV you would:
1. decrease the hertz
2. increase the delta P
3. increase the amplitude
92
What are 3 ways to decrease the removal of CO2 in HFV?
- increase the hertz
- decrease the delta P
- decrease the amplitude
93
Alveolar ventilation during HFV is defined as RR xVt2 therefore changes in volume delivery, (as a function of delta P, frequency, amplitude), have the most significant effect on CO2 elimination
true
94
Repositioning of a patient on HFV is a two person procedure, (nurse and RT).
true
95
What are your primary goals for Abby?
- To maintain adequate oxygenation and ventilation
- To maintain a neutral thermal environment
- To provide fluids and nutrition sufficient to meet metabolic requirement and growth needs
- To maintain intact skin without breakdown
- To provide an environment free of noxious stimulation
- To foster positive parent-infant interaction
96
Why was Abby, the infant in Case Study 2.1, ventilated?
- Abby was ventilated because her respiratory disease was causing hypercapnia and hypoxia.
- Although the hypoxia was being managed by CPAP with 40% oxygen, many NICUs, once an infant’s oxygen requirements reach 30-40%, will opt for mechanical ventilation as an approach to management and delivery of surfactant.
97
There are two main differences between normal breathing and mechanical ventilation. These two differences put infants like Abby at risk for several problems. What are these problems?
- Normal breathing does not cause increased positive pressure within the lungs; mechanical ventilation does.
- Normal breathing is regulated by internal biochemical feedback mechanisms; mechanical ventilation is regulated by the health care professionals manipulating the ventilator.
- The high inspiratory pressures used with mechanical ventilation cause barotrauma and volutrauma to the lung tissue. This can result in edema, inflammation, scarring, overinflation, loss of elasticity, and, if these problems become chronic, this is called Bronchopulmonary Dysplasia.
- The fact that an infant’s normal internal biochemical feedback mechanisms are being bypassed leads to the potential for the ventilator settings to be inappropriate for the infant’s needs. This can result in hypoxia, hypercapnia, and acidosis.
98
Abby was likely ventilated using a pressure controlled, volume guaranteed, time limited mode of ventilation (ACVG). In your own words, explain what this means.
- ACVG means that Abby receives a guaranteed tidal volume with each breath using the least amount of pressure, based on a breath to breath analysis.
- Abby is able to trigger the ventilator to deliver the breath, which will deliver a mandatory breath.
- The mandatory breath delivered will be based on the set tidal volume, the set inspiratory time, using a constant set flow, to deliver the volume with the least amount of pressure.
- If Abby does not trigger the ventilator, the ventilator will deliver a breath based on the set respiratory rate to maintain the desired minute ventilation.
99
The author of the vignette states that Abby required “high ventilatory support for several days.”
What do you think this means? Specifically, what rate and pressure do you think might have been used to ventilate Abby?
- This likely means that in order to adequately ventilate Abby - that is, eliminate CO2 - high inspiratory pressures were required in order to achieve an adequate tidal volume.
- This suggests that her lungs were quite stiff or noncompliant.
- A lot of pressure was required to move a sufficient volume of gas in and out of her lungs. It may also mean that she required a high rate on the ventilator.
- This suggests that she may have been too ill or too immature to overbreathe the ventilator. Pressures > 25 cm H20 may have been needed to inflate her lungs and achieve an adequate tidal volume.
- Ventilator rates as high as 60 may have been required to clear her CO2 if she was not breathing on her own. (Remember that infants normally breathe at a rate of 40-60 breaths per minute).
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What disease does high ventilatory support put Abby at risk for?
- As has already been mentioned, Bronchopulmonary Dysplasia (BPD) is a chronic lung disease that infants who have been ventilated with oxygen are at risk for developing.
- Many of the infants you will see in the clinical area will have this disease.
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What is the rate in ventilator setting?
- Every infant ventilator has an option that permits selection of a range of rates, from as low as 10 breaths per minute to as high as 150 breaths per minute.
- The rate setting determines how many breaths will be delivered by the ventilator in a minute.
- Normally the rate is set between 40 and 60.
- The rationale for this range is that at less than 30 breaths per minute, the infant is likely ready to be off the ventilator.
- More than 60 breaths per minute is not physiologically normal.
- Most infants breathe at a rate of 40 to 60 breaths per minute.
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What is the I time in ventilator setting?
- Infants normally breathe with an inspiratory time of 0.3-0.55 seconds.
- I time controls when inspiration ends and expiration begins.
- relationship between inspiratory time and expiratory time is often referred to as the I:E ratio (1:2)
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What is PIP in ventilator setting??
- The peak inspiratory pressure (PIP) is the maximum pressure in the lungs during inspiration.
- The range of PIPs generally used to ventilate infants is 12 to 25 cm H2O.
*Higher pressures are used to ventilate stiffer lungs;
*lower pressures are used to ventilate more compliant lungs
104
What is volume in ventilator setting?
- The volume set is the amount of gas in mls you wish the lungs to receive during a specific period of time, without exceeding a set PIP.
- The setting of the tidal volume will take into consideration the flow sensor deadspace of 0.9mls.
- The goal volume used in the neonatal population is 4-6 mls/kg.
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What is PEEP in ventilator setting?
-PEEP is the pressure that is maintained within the lungs at the end of expiration.
- The normal range is 5 to 8 cm H2O. What this means is that at the end of expiration a small amount of pressure continues to be applied to the lungs
- rationale for using PEEP with infants relates to the tendency of their alveoli to collapse at the end of every breath
- may still need PEEP to leave a little air in the alveoli, making the next breath easier to take
106
What is O2 concentration in ventilator setting?
- All mechanical ventilators have air/oxygen blenders and can, therefore, deliver oxygen concentrations ranging from room air, 21%, to 100%.
- Infants who are ventilated generally require the same or slightly less oxygen than they required prior to being ventilated.
107
What are the alarms in ventilator setting?
- High/Low minute ventilation (Remember that minute ventilation is MV=TV x RR).
- High/Low Pressure
- High/Low PEEP/CPAP
- High Pressure limit
- High Inspiratory Rate
- Apnea
- Ventilator Inoperative
- Disconnection
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Why is humidification used when baby in intubated?
- When a physician intubates an infant with a tracheostomy or endotracheal tube, these natural humidification structures are bypassed.
- If an infant inspires dry, cool gas for a prolonged period of time, the tracheobronchial mucosa dries and ciliary activity decreases.
- The infant will be unable to clear thick mucus that can then dry and block the airway or provide loci for infection.
- To prevent this drying effect, humidifiers can be placed in the inspiratory line of the ventilator circuit to increase the humidity and temperature of the gas flowing into the lungs.
- Warmed and humidified inspired air can also help to prevent heat loss
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What are some consequences if adequate temperature and humidity on inspired gas is not provided?
- risk of airway damage due to loss of heat and moisture.
- Alteration of mucociliary transport
- Reduced airway defense
- Thickening of secretions
- Reduced airway patency and lung compliance
- increased work of breathing, and
- Hypothermia
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What happens if too much humidity?
- Too much humidity can literally instill infants with condensation (especially small infants) and can occlude the inspiratory hose and interrupt ventilation.
- Excessive rainout (condensation) in the inspiratory hose can be drawn into the infant’s lungs if the inspiratory hose slants downward from the humidifier to infant.
- While the standard practice requires routing the hose so that rainout will drain away from the infant, moving the equipment may inadvertently dump collected rainout into the infant’s airways.
- Sometimes a water trap, a small container hanging beneath the lowest part of the hose, collects rainout.
- Another important consideration of rainout is that it can sometimes collect in the ventilator circuit.
- The ventilator can confuse the vibration of the water in the circuit as a triggered breath from the infant, and deliver extra breaths to the patient.
- The end result can be a very high respiratory rate being delivered.
- Rates as high as 100 can sometimes occur and result in a very low, and dangerous CO2 levels to the infant.
**Please ensure your ventilator is not auto-triggering in this manner.
111
What happens if too little humidity?
Too little humidity can lead to the
- buildup of secretions that can block airways,
- decrease lung compliance,
- enable bacteria to invade mucosa,
- cause atelectasis (collapsed alveoli), and
- promote pneumonia.
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What happens if too hot from humidifer?
- A humidifier that produces excessively hot gases may burn an infant’s airways and cause general hyperthermia in small infants.
- Even though many units incorporate a nonelectric thermal fuse or backup thermostat that will immediately break the heater power circuit when an excessive temperature limit is reached,
- the humidifier and inspiratory tubing can act as a thermal wall (especially if the humidifier holds a large volume of heated water) and produce inspiratory temperatures well above the power cutoff limit.
**Recall from NSNE 7200 the importance of maintaining a neutral thermal environment.
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What are some assessment that should monitored for infants receiving mechanical ventilation (3)?
- clinical assessment of respiratory status, e.g., chest movement, colour, peripheral perfusion.
- blood gas analysis.
- chest x-ray.
- patients efforts of overridding (breathing above the rate/spontaneously) or not
114
What are 4 clinical assessment included with mechanical ventilation?
Colour
- Observe colour for any signs of cyanosis, pallor. and/or mottling, either peripheral or central.
- Note whether color changes with handling, suctioning, etc.
- Use a pulse oximeter to assess changes in O2 saturation during handling and procedures.
- Note perfusion to the extremities.
- Capillary refill time (determined by a 3 second count) should be brisk and extremities should be warm.
- If an infant’s color or perfusion is deteriorating, these could be early signs of hypoxemia because of respiratory insufficiency.
Respirations
- chest rising symmetrically with each positive pressure ventilation?
- infant triggering the ventilator above the set respiratory rate?
- Does the infant look comfortable?
- breath sounds equal and adequate bilaterally?
- Presence of moist breath sounds indicates that the infant may require suctioning.
Heart sounds
- extreme tachycardia or bradycardia may indicate hypoxemia
- heart sounds appear muffled or distant, this is an indication that a pneumothorax
equipment check
- wall suction
- hand bagging
- neopuff
- tubing and connections
- O2 concentration
- mode
- alarms
- humidifier set
115
What is DOPE?
A quick way to remember complications associated with mechanical ventilation is the mnemonic DOPE:
- Displacement/dislodgement
- Obstruction
- Pneumothorax
- Equipment malfunction/disconnection
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What should you do if the ventilators malfunction?
- simply remove the infant from the ventilator and place him/her on a hand bagging system until the problem with the ventilator has been resolved.
- Hand bag the infant using rates, pressures, I times, and a FiO2 that meets the infant’s needs.
- Usually these will be similar parameters to those set on the ventilator
**hand bag the infant and ask someone else to check your circuit.
117
What are some signs if ETT has dislodged into pharynx?
- audible crying (a sure sign the tube is not in the trachea!)
- a large air leak from mouth with bubbling of mucous
- infant handles progressively less well as he/she tires
distended abdomen
- if the infant is feeding, the distended abdomen may cause regurgitation and milk may be visible in the ventilator tubing
- pressures will decrease
- ventilator sounds can be heard over the abdomen
- desaturations.
**if the tube has dislodged into the pharynx, the infant will still be getting oxygen and some positive pressure by the same principle as CPAP
118
What are some signs/responses to self or accidental extubation?
- cyanosis
- bradycardia
- apnea
- little or no air entry in chest
- distended abdomen
- desaturations.
**If an infant demonstrates these responses, immediately call a physician and if he/she is not readily available, remove the tube and hand ventilate
119
What are some responses which indicate the tube may be in the right main stem bronchus include?
- air entry absent or decreased on left side
- air entry present on the right side
- cyanosis
- possible bradycardia
- desaturations.
**complication of displacement is right main stem intubation. This occurs most commonly following intubation if the tube has been inserted too far down. The anatomy of the trachea and main stem bronchi is such that the tube will naturally slip into the right side. If the tape is coming loose on the endotracheal tube, the tube may slip into the trachea further
120
What are some early infant responses to a partially obstructed tube?
- the infant is more mucousy than usual
- it is more difficult to pass the suction catheter
- suctioning is less productive than usual
- the infant begins to indraw in an attempt to draw in more air through the narrowed airway
- the infant becomes restless due to increasing hypoxia due to a narrowed airway
- the pCO2 will be elevated
- SpO2 will be decreased
- the infant will not tolerate handling as well
- decreased breath sounds with harmonic or wheezing sounds over trachea.
**If you notice any of these responses and are concerned that the tube may be plugging, increase the oxygen if the infant appears hypoxic. Suction the ETT with the in-line suction catheter.
121
What are some responses if ETT becomes completely blocked with a mucous plug?
- cyanosis, pallor, mottling
- bradycardia
- initially restless with indrawing followed by apnea and hypotonia - a very ill infant may just become apneic
- little or no air entry bilaterally.
***In this case you must respond quickly, by immediately giving bag mask positive pressure ventilation.
- Call a physician.
- Call a respiratory therapist.
- Call a nursing colleague, instructor, etc.
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What is pneumothorax?
- If breath sounds and/or heart sounds are decreased on one side, chest movement is one sided, and/or decrease saturations, tachycardia and tachypnea are present, the infant may have a pneumothorax.
- In this case also call for help
123
What are some safety measures that nurses are responsible for infants safety during intubation?
- aspiration of stomach contents prior to intubation
- closed-loop communication with the team
- premedication with anticholinergic (e.g., Atropine), sedative (Morphine/Fentanyl), and paralytic (succinycholine).
- increasing volume of QRS on the cardiorespiratory monitor to alert practitioners to infant’s heart rate
- holding the infant still and midline during the procedure
- providing oxygen and suctioning as needed
- timing the duration of the procedure
- monitoring an infant’s responses to the procedure (color, heart rate, tone)
- documenting the procedure
124
What are 3 comfort measures nurses are responsible for infants safety during intubation?
- containment/bundling
- warmth
- medication for sedation and pain.
125
What are the premedications prior to intubations?
- Atropine (an anticholinergic) will help to prevent bradycardia and decrease secretions.
- Sedatives and/or analgesics (Morphine or Fentanyl) are given to facilitate the intubation process, increase comfort, and decrease complications associated with intubation.
- Many NICU’s are also using Succinylcholine to relax the infant’s muscles and used to facilitate neonatal and pediatric rapid sequence intubation in the NICU
** administering atropine prior to succinylcholine to reduce the risk of bradycardia
126
How do you estimate how deep to insert the ETT?
- tip-to-lip measurement is the distance from the tip of the tube to the infant’s upper lip.
- Adding 6 to the infant’s weight in kilograms, gives you an estimate of depth of the endotracheal tube in cm, when visualized at the upper lip.
- Neonates weighing less than 750 g may need endotracheal tube insertion to only 6 cm
**auscultation of bilateral air entry and confirmation by chest x-ray must be completed
127
How ETT intubation confirmed?
- chest x-ray the endotracheal tube may be adjusted and therefore, the measurement as confirmed on x-ray should be used.
- On x-ray the tip of the ETT should be at T1-3 or 2cm above the carina.
128
What are the ETT sizes?
- below 1000g, below 28GA = 2.5mm
- 1000-2000g, 28-34GA = 3.0mm
- greater than 2000, greater than 34 GA = 3.5
129
What are the benefits of successful suctioning intubated patient (4)?
- improves air exchange and breath sounds,
- decreases the peak inspiratory pressure (PIP),
- decreases airway resistance,
- increases dynamic compliance,
- increases tidal volume delivery when using pressure limited ventilation,
- improves arterial blood gas values,
- improves oxygen saturation, and
- removes secretions.
130
What are some risk to suctioning (4)?
- Hypoxemia
- Bradycardia
- Atelactasis
- Bronchospasm
- Increased intracranial pressure
- Trauma to the airway’s mucosal lining and cilia
- Bacterial colonization of the airway
- Ventilator associated pneumonia (VAP)
- Nosocomial sepsis
- Stress
131
What can result from failure to suction when needed?
- plugged tube and
- the trauma of reintubation,
- atelectasis, and
- decreased oxygenation and ventilation
132
What are 2 keys to minimize risk of plugged ETT?
- delivery of adequately warmed, humidified inspirited inspired gases
- optimal hydration.
133
What is the general rule of thumb for suction ETT?
- should only insert the suction catheter into the tube twice during one suctioning procedure
- feel there are still secretions after inserting the catheter twice, it may mean that the infant needs suctioning more frequently
- If the catheter is inserted more often without the infant having a significant rest period, he/she may become severely hypoxic
**Sometimes you may have to increase the oxygen prior to suctioning to prevent hypoxemia during suctioning. If an increase in oxygen is required, it is usual to increase the FiO2 by 0.10;
134
What are some clinical signs that suction is needed (4)?
- oxygen desaturations
- visible and/or audible secretions
- course and/or decreased breath sounds on auscultation
- decreased chest expansion
- changes in respiratory rate and pattern
- bradycardia
- agitation
- decreased tidal volumes
- increased PIP
- changes in blood gas values.
135
What should be done prior, during and after to suctioning?
- Always listen to the chest before and after suctioning. It is possible that you may have dislodged a small mucous plug during suctioning which has become caught in the tube
- Throughout the suctioning procedure, the infant’s heart rate, color, and oxygen saturation should be observed closely.
- Suctioning should be brief to prevent hypoxia and vagal stimulation.
- If the infant desaturates, becomes bradycardic, cyanotic, mottled, or pale during the procedure, discontinue suctioning.
- Check the air entry.
- Increase the FiO2 if need be.
136
Is it sterile technique when suction ETT?
yes
137
What are the two ETT suctioning systems?
- open
- closed
138
What does the open suctioning system vs closed system requires?
open suctioning:
- requires disconnecting the infant from the ventilator whereas the closed system allows passage of a sterile suction catheter through the ETT without disconnecting the infant from the ventilator
closed suctioning:
- achieved by having an in-line suction catheter.
- By not having to disconnect the infant from the closed suctioning systems (in-line suction catheters) may help maintain functional residual lung capacity (FRC) during a suction procedure, decreasing desaturation and bradycardia event.
139
What are the risks to open systems?
- Hypoxemia, atelectasis, pneumonia (VAP), trauma to the airway, sepsis, dislodgement of the ETT and changes in heart rate, blood pressure, and cerebral blood flow.
- It has been shown that systolic BP increased significantly more during open suctioning (than closed) and a significant decrease in heart rate.
140
What are 3 benefits of closed system?
- Minimizes changes in oxygen saturation and decreases atelectasis.
- Shorter length of time required for all physiologic parameters to return to baseline values seen with closed suctioning.
- Decreased risk of VAP and associated bacterial infections
141
What are some guidelines for ETT suctioning?
- Suctioning an ETT using an open system is a sterile procedure, while suctioning an ETT using a closed system is a clean procedure.
- Suctioning should be done as a two person procedure.
- The role of the assistant is to provide developmental support to the infant during this stressful event while being prepared to assist if the baby decompensates or has a tube emergency.
- This support is provided by containing the infant’s limbs in a midline, flexed position.
142
Should infants oxygen be increased during suctioning?
- Increasing the oxygen from baseline requirements should be based on the infant’s response to handling and previous suctioning events.
- Both hypoxemia and hyperoxemia should be avoided.
- Hyperoxemia is associated with oxygen free-radical damage which in turn is associated with morbidities such as chronic lung disease, periventricular leukomalacia, retinopathy of prematurity and bronchopulmonary displasia
- The oxygen may be set initially to approximately 10% above the ventilator, adjusting the oxygen requirements to maintain the infant’s target SpO2 during the suctioning procedure.
143
How far should suction ETT catheter be inserted?
- The suction catheter should be inserted so its tip reaches the end of the ETT and does not touch the carina.
- At some sites, after reviewing the chest x-ray, an additional 0.5cm past the end of the ETT is measured for suction depth.
- This predetermined length (the length of the ETT plus the adapter) should be posted at the infant’s bedside.
- Passing the suction catheter beyond the tip of the ETT can stimulate the vagal nerve possibly causing a bradycardia and hypotension and/or cause trauma or irritation to the mucosa and respiratory epithelium.
144
How long is the duration of ETT suctioning?
- duration of suctioning should be kept to a minimum as mechanical ventilation is interrupted during suctioning.
- As a general rule of thumb insert the suction catheter into the ETT two times during one suctioning event.
- Limiting the number of catheter passes reduces the risk of hypoxemia, mucosal trauma, and related injuries.
- It is strongly suggested that when more than one catheter pass is needed, the infant is given a recovery period between passes to allow O2 levels to return to baseline.
- If you feel there are still secretions after inserting the catheter twice, it may mean that the infant needs suctioning more frequently.
145
Should NS instillation be used?
- best practice suggests that sterile NS should NOT be instilled during ETT suctioning.
**Small amounts of sterile NS may be used after suctioning to cleanse the catheter after suctioning is complete.
146
What are the risks of NS instillations during ETT suctioning?
- hypoxemia
- bradycardia (vagal response)
- barrier to gas exchange
- bronchospasms
- dislodgement of bacterial biofilm colonizing the ETT into the lower airway
- increased risk of nosocomial pneumonia and infections
- increased intracranial pressure.
147
Is oral suctioning a routine event?
no
- it can be uncomfortable, may be traumatic to the oral mucosa and is disruptive to developmental supportive care.
- Assess whether secretions can be removed without suctioning with a wipe.
- Suctioning must be performed only when necessary to maintain airway patency.
**Mouth then nasal suctioning must be performed prior to ETT suctioning on intubated infants (as per VAP prevention protocols) irrespective of open or closed suction systems.
148
What is chest percussion?
- Chest percussion by a physiotherapist may be helpful in infants with atelectasis in specific areas of their lungs, or to help mobilize thick, tenacious secretions that may lead to airway obstruction.
- Very sick infants may not tolerate chest percussion and careful weighing of the benefits versus the risks must be done.
- Infants with metabolic bone disease, for example, may not be candidates for chest percussion
149
What is ventilator associated pneumonia (VAP)?
- Ventilator Associated Pneumonia (VAP) is defined as pneumonia that develops 48 hours after a patient has been placed on mechanical ventilation.
- VAP can be of bacterial, viral, or even fungal etiology.
150
What are some of the causes linked to onset of VAP during mechanical ventilation?
- Aspiration of oropharyngeal secretions
- Aspiration of esophageal/gastric contents
- Inhalation of infectious material
- Contamination of the ventilator circuit
- Advancement of infectious material into the trachea/lungs during intubation, and suctioning.
151
What art some procedures added to the care of mechanically ventilated infants in order to help reduce the risk of acquiring VAP?
- Ensuring proper placement of the enteral feeding tube to prevent aspiration of esophageal/gastric contents
- Elevating the head of the bed 34-45 degrees again to prevent aspiration
- When suctioning, suction the mouth and nose first, before suctioning the endotracheal tube to prevent advancement of infectious materials into the trachea and lungs
- Implementing the use of an in-line suction catheter and sterile suction techniques
- Changing of ventilator circuits only when grossly contaminated to help maintain a closed system
- Avoiding contamination of the ventilator circuit from condensate
- Oral vs. nasal intubation
- Positioning of the ventilator circuit so that the flow of condensation will be away from the patient.
- The use of non-invasive ventilation when possible
- DILIGENT HAND WASHING!!!
152
What does weaning of ventilated infant refers to?
- refers to decreasing the respiratory support by the ventilator, while the infant increases the amount of respiratory support they provide themselves.
153
What are some ways to wean /decreased respiratory support by ventilator?
- Decreasing the respiratory rate
- Decreasing the tidal volume
- Decreasing the PIP/PEEP
- Decreasing the FiO2
- Changing the mode of ventilation from HFO/HFOV to ACVG/ ACVG to PSV/ PSV+VG/VG to CPAP
154
Why is it that only one ventilator parameter is decreased at a time during weaning?
For example,
- either the rate or the peak inspiratory pressure will be decreased.
- Usually, if the PIP is high, this is decreased first since high PIP is related to chronic lung damage.
- With volume ventilation, weaning may include changing modes to one which provides less support.
- Oxygen will also be gradually reduced during the weaning process.
- During this process, it is critical that you observe the infant’s response to each change in ventilator settings by noting physiologic responses (e.g., color, drive to breathe) and blood gas responses (e.g., oximeter, transcutaneous pCO2, arterial, or capillary blood gas values).
155
When can CPAP be tried be used during the weaning process?
- Once an infant has reached a minimum level of ventilation and is breathing well between ventilator breaths,
- CPAP may be tried or the infant may be extubated and given supplemental oxygen.
156
What are some DSC for infants on ventilator?
meeting developmental needs and at the same time meeting oxygen, ventilation, and safety needs is a challenge
- Organize your own care to provide rest periods and avoid any unnecessary handling. Coordinate the activities of others (physicians, respiratory therapists, x-ray technicians, lab technicians, physiotherapists, etc.) to ensure that infants are not over handled.
- The need for activity must be balanced with the need for rest. Stimulation and skin-to-skin (kangaroo) cuddling become important aspects of care, for both parents and infants! Stimulation and skin-to-skin, however, should not jeopardize an infant’s ability to meet his/her need for oxygen
157
What are a few contraindications that exclude infant from skin to skin?
- low-lying central umbilical lines,
- an infant on cooling protocol, and
- chest tubes
158
How should baby be transferred for skin to skin?
- When preparing to move the infant onto the parents, you must get a second pair of hands to assist with the ventilator tubing and IV lines.
- Use the standing transfer technique if the parent is mobile enough.
- Many sites will have a clinical guideline or skill on how to help a parent with a standing transfer and this is the preferred way to have parents picking up their infants.
- Have parents sit in a chair very close to the ventilator and ensure safety equipment will reach the infant, should the ETT become dislodged during the cuddle.
- Secure the ventilator tubing with strong tape to the chair, or wherever the tubing falls naturally.
- Stay close by the parents and monitor the infant’s condition throughout the skin-to-skin. Skin-to-skin should only occur at a time when the infant is stable.
- Having said this, we certainly do not want to discourage parents from holding their infant!
** skin to skin cuddling is so beneficial for all aspects of the neonate’s development.
159
What can be mention to parents for skin to skin?
- Be sure to discuss the plan with them ahead of time. Reassure them that they are holding properly, doing a good job, etc.
- Point out changes in their infant’s condition during skin-to-skin which indicate relaxation and enjoyment (e.g., ↓ agitation, ↑ O2 saturation, improved color, eye contact).
- Infants will often need less supplemental oxygen both during and after an hour-long skin-to-skin session.
- Additionally, infants will usually fall into a deep sleep state during their skin¬-to¬-skin time
**Try to coordinate a time that works for the family for cuddles, and explore what this experience may be like for that particular family.
160
What is one important thing to have within reach for ETT infants during skin to skin?
- It is important to make sure that your bag and mask and suctioning is within reach if your baby suddenly deteriorates
