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Winter 2018-Patient Assessment > Respiratory Assessment > Flashcards

Respiratory Assessment Flashcards

1
Q

PPV-Increased FRC

A
  • FRC is the volume in the lungs at the end of a tidal breath
  • When PEEP/CPAP is used
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2
Q

Alveolar Minute Ventilation (VA)

A

More accurately represents the effective ventilation (the minute volume actually responsible for maintaining the PaCO2)

ṾA = RR x (VT-VDphys)

So it requires accurate measurement of VDphys

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3
Q

Lower Infection Point

A

lower inflection point on inspiratory limb = place where there is a sudden increase in compliance (set PEEP here to maintain FRC)

Change in the slope at the lower end of the inspiratory curve

Some think that this point can be used to help recruitment of all/most/some of the collapsed and recruitable alveoli -> helps at setting PEEP

The above assumption has been questioned because there are many limitations to this approach: recent ventilation history, variability due to underlying lung disease, presence of decreased compliance of the abdominal and chest wall, the greater importance of the expiratory component of the curve.

pig tail at the bottom indicates patient triggering (bigger the pig tail, higher the WOB to trigger breath)

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4
Q

Diagnostics

A

Sputum Culture and Sensitivty

Bronchoalveolar Lavage

Diagnstic Imaging-CXR, CT, V/Q Scan

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5
Q

PPV and Nervous System

ICP and Cerebral Perfusion

A

CPP=MAP-ICP

May decrease CPP secondary to a decreased in mean BP (compromised cardiac function)

CPP can be affect from both sides because MAP may decrease and ICP will increase

ICP increases secondaryto a increased CVP (as venous return from the head may be reduced)

Hyperventilation (PaCO2 < 35) causes cerebral vasoconstriction therefore decreases CP and ICP

This is a temporary effect!

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6
Q

PC CMV Absolute Pressure

Decreased Ti sec

A

Ti tot Decreased

Te Increase

I:E Decrease

Pmean Decrease

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7
Q

Tracheostomy Tubes Assessment

A
  • Size/type
  • Cuff pressure
  • Inspection of stoma site
  • Inspection and assessment of securing method
    • The ties should be just snug enough to get two fingers underneath
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8
Q

Types of Deadspace

A
  • Anatomical Deadspace (VDanat)
    • Volume of gas in the conducting airways
    • ~ 1 mL/lb = 2.2 mL/kg
  • Alveolar deadspace (VDalv)
    • Volume of gas ventilating unperfused alveoli
  • Physiological deadspace (VDphys)
    • The total of anatomical and alveolar deadspace
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9
Q

Arterial Partial Pressure of Oxygen

A

Abbreviation: PaO2

Description: Oxygen content in arterial blood

Normal: 100-80 mmHg

Measured: ABG

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10
Q

Low Anion Gap

A

= disruption of anion balance; usually due to a loss of HCO3- balanced by an increased Cl-

  • Gastric losses of HCO3-
  • Diarrhea
  • (Note: not vomiting—this causes hypochloremia and alkalosis)
  • Renal loss of HCO3-
  • Renal tubular acidosis
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11
Q

PC CMV Absolute Pressures

Decreased in Compliance

A

Vt Decrease

Ve Decrease

Ti dyn Decrease

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12
Q

PaCO2

A

The best index of effective ventilation

Is dependant upon the balance of CO2 production and alveolar minute ventilation

It is the inverse of VA (Avleoar minute ventilation; and how fast we are blowing off CO2)

If you have a high CO2 the you are not ventilating

If you have a low CO2 you at least have the ability to do so but we still need to figure out why you are doing it

VCO2 is how fast we are producing CO2

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13
Q

PPV Shunt and Deadspace

A

There is increased deadspace ventilation as well as an increased shunt in a mechanically ventilated patient resulting in an overall V/Q mismatch

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14
Q

PC CMV Absolute Pressure

Increased in PEEP

A

PIP Decrease

Pplat Decrease

Pmean Increased

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15
Q

Types of Trach Tubes

A

Fenestrated-If both the inner and outer cannula are fenestrated suctioning can go through both tubes and poke someone in the back of the neck

Cuffed

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16
Q

PPV and GI System

A

Increased permeability of gastric mucosa

Increased GI bleeds and gastric ulcers in mechanically ventilated patients

Consider use of antacids or H2-blocking agents to reduce gastric secretions

Potential for gastric distension if PPV done via mask

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17
Q

PC CMV Delta Pressure

Decreased Rate

A

Ve Decreased

Te Increases

I:E Decrease

Pmean Decrease

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18
Q

PC CMV Delta Pressure

Increased Ti sec

A

Ti tot Increased

Te Decrease

I:E Increased

Pmean Increased

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19
Q

Ventilator Associated Lung Injury

A

Ventilator-Induced Injury also be called Ventilator Associated Lung Injury (VALI), which will capture other problems that can be associated with PPV

VAP, air-trapping, ventilator-patient dsy-synchrony (vent is not responsive to patient’s breathing efforts which is uncomfortable and can be dangerous if there are double breaths)

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20
Q

VC VMC Decreased Resistance

A

PIP Decreases

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21
Q

IPPA

A

The first thing that should be done is a visual inspection to make sure that the patient is stable

Should repeat the appropriate part of the assessment (at a minimum) after an intervention is completed

Trends are always important

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22
Q

Measuring Compliance Clinically

A

Truly we are measuring total compliance (Ctotal)

The compliance of the lung (CL) and chest wall (CW) combined

Does CTOTAL = CL + CW ?? NO!

Because the lung and chest wall work in opposite directions, the compliance is effectively half the original components

Ctotal = (CL * CW) / (CL + CW)

The assumption is made that the chest wall compliance is unchanging, thus; changes in Cstat can reflect changes in CL.

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23
Q

PC CMV Absolute Pressure

Increased Rate

A

Ve Increase

Te Decrease

I:E Increase

Pmean Increase

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24
Q

What determines how long for breath to get out of the body

A

It is passive so compliance, resistance, (time constant)

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25
Q

VC-CMV

Vt Increased

A

Everything will increase with the exception of Ve which decrease and I:E Ratio which increased (specifically the E portion of this ratio will decrease)

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26
Q

PPV-Increased Deadspace Ventilation

A
  • Normal VD/Vt is 0.25-0.40 but is increased to 0.40-0.60 in mechanical ventilation
  • Distribution of a positive pressure breath goes more to the apices and less to the bases compared to a spontaneous breath
    • This happens because in the apices the whole weight of the lung will be pulling down so that the alveoli is already stretched/opened
      • Ex. When the patient is standing up the lung will be pulling down
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27
Q

PPV and the CVS

A
  • Positive pressure ventilation will impede venous return and may result in decreased CO and therefore decrease BP
    • Hypotension rarely occurs in normal individuals receiving PPV due to the body’s compensatory mechanisms
  • Altered right and left ventilicular function
  • Decrease endocradial blood flood
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28
Q

Peak Inspiratory Pressure

A

The maximum pressure delivered during

Does not necessarily reflect pressures in the lungs

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29
Q

VC VMC Increased Resistance

A

PIP Increases

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30
Q

Lung Protective Strategies-Ensure the correct placement of ETT

A

Want 3-5 cm above the carina as the tube will move as the head moves, and if we do not have a buffer zone it can extend too far

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31
Q

Compliance

A

A measure of the distensibility of the lung

Reciprocal of elastance

Normal is 60-100 mL/cmH2O

< 25 - 30 cmH2O in ARDS

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32
Q

PC CMV

Delta Pressures

Resistance Decreased

A

Ti dyn Decreased

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33
Q

Disorders and changes in Cstat and CL

A

Dirsorders in which changes in Cstat may not be reflective of changes in the CL!

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34
Q

VC CMV PEEP Decrease

A

PIP Decrease

Pplat Decrease

Pmean Decrease

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35
Q

How if Oxygen Carried in the Blood

A

1) Hemoglobin (Hb)

  • Oxyhemoglobin
  • Major carrier of O2
  • 1.34 of O2 per gram of Hg (when fully saturated)

2) Dissolved in plasma

  • Determined by Henry’s Law
  • Account for a small percent of O2 transport
  • 0.003 mL/dL/mmHg
  • PO2*0.003=ml/dl dissolved O2
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36
Q

CvO2 Calculation

A

CvO2=(Hb x 1.34 ml/g) * SvO2 + (PvO2 x 0.003 ml/100ml/mmHg)

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37
Q

Shunt fraction %

A

<10%-Compatible with normal lungs

10%-19%-Seldom requires significant ventilatory support

20%-29%-Significant abnormality; requires PEEP or CPAP

30% or more-Severe disease; life-threatening; requires aggressive mechanical ventilation with PEEP

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38
Q

Anion Gap

A

The anion gap is the difference between the measured cations and the measured anions

Helps determine whether a decrease in HCO3- is due to disruption of normal anion balance or the presence of an abnormal acid anion (i.e. cause of a metabolic acidosis)

Anion Gap = (Na+) - (Cl- + HC03-)

Normal: 9 – 14 mmol/L

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39
Q

PC CMV Pressure Control Delta

Increased PC

A

PIP Increased

Pplat Increased

Vt Increased

Ve Increased

Pmean Increased

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40
Q

Non-Invasive Interface Assessment

A

Assess mask fit/leak

Patient comfort

Observation of skin necrosis/irritation

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41
Q

VC CMV Increased Compliance

A

PIP Decrease

Pplat Decrease

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42
Q

What Forces need to be Overcome for Breathing

A

When it comes to ventilation the pt. has to overcome reistance (non-elastic resistance-diamater of the airways) and compliance (elastic resistance), and these are not static forces

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43
Q

PPV-Air Trapping

A
  • With increased airway resistance more time is needed for exhalation
    • Pt. still in exhalation when the ventilator gives next breath so the air that was not exhaled is now trapped
  • If there is not enough time before the next breath it will result in air-trapping
    • Air-trapping or auto-PEEP, can also be a result of obstructive lung disease (asthma, COPD)
    • Auto-PEEP can be measured through an expiratory pause maneuver
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44
Q

Atelectrauma

A
  • Injury that results due to a repeated opening and closing of the alveoli at low lung volumes
    • Can also result in volutrauma because air will only want to enter the open alveoli
    • The collapse itself it not always damaging even though it can cause V/Q mismatching but where atelectrauma is damaging is the repeated opening and closing
  • Associated with inadequate PEEP as an appropriate PEEP will prevent de-recruitment of alveoli
    • Physiologic PEEP is generally 3-5 cmH2O and is caused by the backpressure in the larynx when the vocal cords are closed
    • Minimum PEEP is 5 cmH2O
    • In neonates can be associated with inadequate CPAP
  • A longer Ti and higher PEEP will also allows for more alveoli to open
  • Usually occurs in dependent area
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45
Q

Mean Airway Pressure

A

The average pressure delivered over one minute, as measured by the ventilator

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46
Q

Oxygen Saturation

A

Abbreviation: SpO2

Description: Oxygen content in arterial blood

Normal: >90%

Measured: Pulse Oximeter

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47
Q

PPV and Renal System

A
  • Response from hemodynamic changes
    • Urinary output (UO) when CO causes renal perfusion
  • Endocrinological Effects
    • Increased ADH release
    • Decreased ANP release
    • Activation of the renin-angiotensin-aldosterone system
  • Abnormal ABGsPaO2 results in decreased renal function and UO
    • Function is dramatically decreased when < 40 mmHg
    • PaCO2 > 65 mmHg decreases kidney function
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48
Q

When assessing Oxygenation and Ventilation What do we Look at

A

Ventilator Settings

ABG, SpO2, ETCO2, TC

Ventilator Orders

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49
Q

Endotracheal Tube Assessment

A
  • Size/Type
  • Depth
    • Should be the same as confirmation on CXR or adjusted to such
  • Position in the Mouth
    • Should be repositioned Q24 or more frequently
    • There are ETT attachment devices that will allow you to easily move the ETT without undoing everything and to help prevent pressure sores
  • Cuff pressure
    • There are automated cuff pressure monitors
  • Inspection and assessment of the securing method
    • Look for any skin necrosis/irritation
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50
Q

PPV and Muscle Function

A

Any muscle not being used is subject to atrophy

In patient’s with prolonged mechanical ventilation both muscle endurance and strength is compromised

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51
Q

VC CMV Decreased Compliance

A

PIP Increases

Pplat Increase

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52
Q

PC CMV Delta Pressure

Decreased Ti sec

A

Ti tot Decreased

Te Increase

I:E Decrease

Pmean Decrease

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53
Q

Lung Protective Strategies-Sigh Breaths

A

Avoid sigh breaths with high tidal volumes and long inspiratory pauses

These sigh breaths are not used very much anymore

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54
Q

Alveolus Partial Pressure of Oxygen

A

Abbreviation: PAO2

Description: The oxygen content at the alveolus

Calculation: PAO2= [FiO2- (Pbaro-PH2O)] - PaCO2/0.80

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55
Q

PC CMV Delta Pressures

Increased in Compliance

A

Vt Increase

Minute Ventilation Increase

Ti Dyn Increased

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56
Q

Where is the air in a subcutaneous emphysema

A

Where is the air in a subcutaneous emphysema is when the air collects underneath the skin

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57
Q

Causes of a High Anion Gap

A

= presence of an abnormal acid

  • Lactic acidosis
  • Ketoacidosis
  • Diabetes or alcohol abuse
  • Toxins
  • Methanol
  • Ethylene glycol
  • Propylene glycol
  • Aspirin (acetylsalicylic acid)
  • Uremia (kidney failure)
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58
Q

Oxygen Toxicity

A

Want to try and keep FiO2 lower than 60% as above which this risk for O2 toxicity will greatly increase

So just because a blood gas looks good does not mean there is no work to do

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59
Q

VC CMV Increased Flow

A

PIP Increased

Tidyn Decreased

Titot Decreased

Te Increase

I:E Decreased

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60
Q

PC CMV Absolute Pressure

Decreased Rate

A

Ve Decreased

Te Increases

I:E Decrease

Pmean Decrease

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61
Q

Deadspace (VD)

A

The volume of gas that is inhaled but does not take part in gas exchange

VDphys = VDanat + VDalv

As deadspace increases the work of breathing to maintain alveolar ventilation is increased

For a given PaCO2, as the VD is increased the ṾE must increase as well, in order to maintain PaCO2

At ṾE > 10 LPM there is increased probability of respiratory failure developing 2° to muscle fatigue

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62
Q

Lung Protective Strategies-Minimize De-Recruitment and Atelectrauma

A

Use the appropriate PEEP

By minimizing the risk of these VILI will minimize the release of inflammatory mediators and the resultant biotrauma

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63
Q

A reliable index of poor oxygenation…

A

A reliable index of poor oxygenation is if FIO2 > 0.50 and PaO2 < 100 mm Hg and this means that the patient is getting a lot of oxygen but for some reason it is not getting into their blood

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64
Q

PPV-Increase Intrapulmonary Shunt

A

Perfusion will go to gravity dependent areas and ventilation will go to gravity independent areas

The gravity dependent areas will be located on the posterior side when the patient is lying on their back

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65
Q

Oxygen Index

A

OI = (FiO2 * MAP *100) / PaO2

A calculation that takes into account the mean airway pressure (MAP)

If you are using FiO2 as a decimal then times by 100 if you are using it was a whole number then you do not need to multiple by 100

Positively correlated with mortality risk

You want a low OI (the lower the better) with <5 being normal

When you are in the 20 you need to begin to look at things such as ECMO because you lungs can no longer properly oxygenate the blood

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66
Q

Assessing Ventilatory Mechanics

A
  • Always looking to see if the follwing are changed
    • Compliance
    • Resistance
      • Auto-PEEP
  • Done through an assessment of the:
    • Ventilating pressures/volumes
    • Waveforms
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67
Q

P(A-a)O2 Critical Number

A

Critical Numbers > 350 mmHg when a person is on oxygen

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68
Q

Biotrauma

A

The lung will release inflammatory mediators that will attack lung tissue, as a result of volutrauma and/or atelectrauma

This results in lung injury that resembles ARDS

The inflammatory mediators can also enter the systemic circulation and result in injury in other organs. Meaning that poorly manage ventilation can lead to serious organ dysfunction in other areas of the body. All of the blood in the body will pass through the lungs which is why the inflammatory mediators can travel to the other parts of the body. This also means that severe injury/infection from other parts of the body can result in ARDS from the inflammatory mediators released from other parts of the body

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69
Q

Arterial O2 Content

A

Abbreviation: CaO2

Description: Total amount of oxygen contained in arterial blood (going to the body)

Calculation: CaO2=(Hb x 1.34 ml/g) * SaO2 + (PaO2 x 0.003 ml/100ml/mmHg)

Normal: 16-22 mL/dL (vol %)

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70
Q

Lung Volume Recruitment Maneuver

A

Over time the alveolar units will collapse when awake we will sigh or yawn to help prevent this collapse, when a patient is sedated and paralyzed they will be unable to yawn or sigh meaning we will have to do it for them

Use high pressure at 30-40 and hold for 30-40 seconds

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71
Q

VC-CMV-Decreased Rate

A

Minute Ventilation Decreases

Te Increases

I:E Decrease

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72
Q

Oxygen Dissociation Curve-Left Shift

A
  • Increased Affinity for Oxygen
  • Decreased temp
  • Decreased 2-3 DPG
  • Decreased [H++]
  • Increased pH
  • CO
    • Because once it has bound to CO it will want to bound with more O2 but it is still easier to bond with CO because there is a stronger affinity
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73
Q

The Transmission of Positive Pressure

A
  • Positive pressure ventilation (and use of PEEP) will increases intrapleural pressure, because how much of the pressure we are pushing in it transmitted to pleural membrane, as well as and intrathoracic pressures
  • The extent of the transmission is dependent on:
    • Amount of PEEP and PPV
      • This become more and more of an issue and PEEP and PPV becomes higher
    • Lung compliance
      • Low C (e.g. ARDS): Pressure transmission significantly reduced
        • Low compliance means that there is a higher elastic recoil (stiff lungs) and the lungs pulling inwards working against our positive pressure ventilation trying to push outwards
      • High C (e.g. COPD): Pressure transmission is highest
      • Can be regionally affected due to disease process-eg. pneumonia, atelectasis
    • Thoracic compliance
      • Thoracic compliance is the resistance of the chest to expansion
      • Hemodynamic compromise is most likely to occur when thoracic compliance is low (e.g. Abdominal distension, thoracic deformities-Kyphoscoliosis)
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74
Q

VC CMV Decreased Flow

A

PIP Decrease

Tidyn Increases

Titot Increases

Te Increases

I:E Increases

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75
Q

Plateau Pressure

A

Reflects the pressure in lung at end inspiration

Requires an inspiratory pause maneuver to measure

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76
Q

PC CMV

Absolute Pressures

Resistance Increased

A

Ti dyn Increase

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77
Q

Murray Lung Injury Score

A
  • Quantifies the level of lung injury in ALI/ARDSe
  • A composite score that takes into account the following four factors:
    • CXR findings
    • PaO2/FiO2
    • PEEP setting
    • Lung compliance
  • No lung injury would be a score of 0
  • Not commonly used clinically but can be used more in research
  • The specific scoring will not be testable (but what is above will be)
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78
Q

P/F Normals

A

Normal P/F ratio is 400 to 500

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79
Q

VC CMV PEEP Increase

A

PIP Increase

Pplat Increase

Pmean Increases

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80
Q

VC-CMV-Increased Rate

A

Minute Ventilation Increases

Te Decreases

I:E Increases

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81
Q

Ventilator-Induced Injury

A

The effect of PPV on the respiratory system

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82
Q

DOPE

A

When a person deteriorates rapidly well on a mechanical vent we can use the acronym of DOPE, which stands for

  • Displacement of ETT
  • Obstruction of ETT
    • At this point try to suction the placement, and if the suction gets stuck it means that there is an obstruction
  • Pneumothorax
    • Preventing air from entering the lungs.
    • When there is a rapid deterioration you will not have enough time to get an x-ray so it is at this time you will want to use your IPPA to determine the likelihood of a pneumothorax
  • Equipment Malfunction
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83
Q

PC CMV

Absolute Pressures

Resistance Decreased

A

Ti dyn Decreased

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84
Q

Shear Stress

A

Related to atelectrauma

This is the strain exerted on the alveolar wall between the expanded lung unit and de-recruited lung unit

Occurs in interstitial space between the open and the closed alveoli

Capillary injury and release of inflammatory mediators results

This can be a common problem in neonates as the alveoli can collapse easily, and is why we tend to use CPAP with neonates to keep the lung open

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85
Q

Therapeutic Interventions

A

Chest Tubes

Humidity

Bronchopulmonary Hyigene- VAP Protocol, CPT, bronchoscopy

Ventilator Strategies-Lung proctective, LVRM, prone proning

Readiness for weaning

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86
Q

PC CMV Delta Pressures

Decrease in Compliance

A

Vt Decrease

Minute Ventilation Decrease

Ti Dyn Decrease

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87
Q

Lung Protective Strategies-Appropraite Volumes

A
  • Use appropriate volumes and make sure not to over ventilate
    • 6-8 mL/kg in normal lungs and 4-6 mL/kg in ARDS
    • Maintain alveolar pressure <30 cmH2O
    • Consider permissive hypercapniaWe don’t always need to ventilate to normal blood gases as sometimes a high CO2 can be used as a protective strategy
      • People will not die because there high CO2 is high they will die because their O2 is low, meaning we should sacrifice ventilation before we sacrifice oxygenation
      • It is more important to monitor pH than CO2, but we can get orders to just keep pH higher than 7.25
88
Q

PC CMV Absolute Pressure

Decreased in PEEP

A

PIP Increased

Pplat Increased

Pmean Decreased

89
Q

Monitors

A

Pulse oximeters

Co-Oximeters

Capnographers

Transcutaneous

90
Q

Pharmacological Intreventions

A

Inhaled Medications

Systemic Respirtory Medications

Specialty Gases

91
Q

Ventilator Assessment

A

Because this is a complexed task it overlap different assessment categories

  • Basic Assessment
    • Basic respiratory parameters
    • Because ventilator is ventilating the lung, part of chest assessment is checking the ventilator
  • Non-Patient Assessment
    • Circuits
    • Device check
    • Preventative Maintenance
  • Monitoring and Diagnostics
    • Continuous display of waveforms/parameters
    • Lung mechanics and WOB
  • Therapeutic Intervention
    • Supports respiratory system
92
Q

PPV-Pulmonary Vascular Resistance

A
  • May decrease due to an improved ABGs
    • Giving oxygen will dilate vasculature
  • May be increased due to compression of alveolar capillaries and over distension of alveoli
    • Can also result in a decreased pulmonary perfusion
  • This means that both hypoxemia and high pressure from PPV can cause higher PVR, so in order to reverse it we need to known the mechanism that it causing it
    • This is difficult to determine at the bedside, but new technology is coming out in order to make this easier
93
Q

Where is the air in a Pneumothorax

A

Pneumothorax is when air leaks into the space between the lung and chest wall

94
Q

PPV and Thoracic Pump

A
  • Spontaneous Breath
    • Diagram contracts to create a negative pressure and the negative pressure will also stretch the vena cava and pulls the venues blood from extremities against gravity, ultimately improving venous return to the heart.
  • Positive Pressure Breath
    • The opposite is occurring because we are pushing pressure in and making atrium smaller and restricting venous return.
    • We are also assuming the right ventricular output will decrease as well.
    • What the picture below is showing will not happen for all pt. as some pt. may be more susceptible than others
95
Q

Disorders that cause Increase Compliance

A

Increased Lung Compliance

  • Improvement in any of the above, pulmonary emphysema

Increased Thoracic Compliance

  • Improvement in any of the above, flail chest, position change—sitting patient up
96
Q

Non-Patient Assessment-Ventilator Related

A
  • Ventilator Circuit Changed
    • Scheduled Change
    • Soiled
    • Leak Test Failure
    • Humidification Delivery Changes
  • Ventilator Change
    • Routine Change for PM
    • Changed- Mechanical Failure
    • Not Changed-Patient Unstable
  • Device Checks Performed
    • Automated
    • Pressure Test
97
Q

PC CMV Absolute Pressures

Increased in Compliance

A

Vt Increase

Ve Increase

Ti Dyn Increased

98
Q

Oxygen Dissociation Curve-Right Shift

A
  • Reduced Affinity (tendency to bind) for Oxygen
  • Increased temp
  • Increased 2-3 DPG
  • Increased [H++]
    • Decreased pH
      • A decrease in the amount of O2 associated with hemoglobin in response to a decreased pH is known as the Bohr Effect
99
Q

Non-Patient Assessment

A

Airway Safety Equitment

Suction Equitment

Humidification Equitment

Vent/Circuit Maintenance

100
Q

Oxygen-Dissociation Curve

A

As each of the four binding sites on a Hgb molecule binds to an O2 molecule its attraction to other O2 molecules will increase. This is why there is the steep curve at the beginning.

Once all the binding sites have been filled up (hemoglobin is saturated) the curve will plateau. This point will be at a saturation of 90% and a PaO2 of ~60 mmHg. Above this point big changes in oxygenation will result in small chnges in PaO2.

At sat of 50% there is a PO2 of 27

Review curve shifts

Right sided shift- increased temp, increased CO2, decreased pH (increased hydrogen ion concentration), increased 2,3 DPG. So increased everything except pH which decreases

101
Q

PPV and Psychological States

A

The continued stress of mechanical ventilation can result in:

  • Insomnia/Sleep Deprivation
  • Anxiety/Frustration
  • Withdrawal Syndromes
  • Depression
  • Feelings of helplessness, loss of control
    • Can become psychologically dependent upon the machine
  • Fear
102
Q

VC-CMV Vt Decrease

A

Everything will decrease with the exception of Ve which increase and I:E Ratio which decreased (specifically the E portion of this ratio will increase)

103
Q

VC CMV Decreased Insp. Pause

A

Titotal Decrease

Te Increase

I:E Decrease

Pmean Decrease

104
Q

TIME CONSTANT

A

Time Constant=Resistance x Compliance

A single time constant is the time it will take to inflate 63% of alveolar units

Five time constants is when all alveolar units are expanded

RR can be broken down to inspiratory time and by default exhalation time

If exhalation time is too short then we can have air trapping

Strategies to increase Te= Decrease Ti

105
Q

Causes of a High P(A-a)O2

A

Oxygen is not being effectively transferred from alveoli to the blood

V/Q Mismatch

Right to Left Shunt

Alveolar hypoventilation

Diffusion Defect

106
Q

PPV-Mechanical Bronchodilation

A

Positive pressure dilates the conducting airway

107
Q

Volutrauma

A

Related to a high transpulmonary pressure that results in a overdistension of the alveoli, as air will always follow the path of least resistance and will then over distend the non diseased alveoli sac

If the sac becomes rupture and not just over distended then it is considered to be barotrauma not volutrauma

The stretch in the alveoli will cause a “leaky” AC membrane (gaps between the alveoli cells) which cause edema formation in the area which results in the release of inflammation mediators and a presentation that is similar to ARDS (massive inflammation in the lungs) and the edema can leak secondary into the alveoli

108
Q

P/F Ratio < 300 and <200

A

< 300 = in acute lung injury (ALI) also known as early ARDS

< 200 = in acute respiratory distress syndrome (ARDS)

109
Q

Hypoxemia Classifications

A

Normal PaO2= 100-80 mmHg

Mild PaO2= 60-79 mmHg

Moderate PaO2= 40-59 mmHg

Severe PaO2= Less than 40 mmHg

110
Q

Barotrauma

A

The most acute, immediate, and severe form of VILI

Risk increases with the level of alveolar pressure (Pplateau) and the extent of lung injury or previous lung disease

Will occur from trying to push air in too fast

Results in air outside of the alveoli (extra-alveolar air) due to the positive pressure rupturing the A/C membrane

Can result in air-leak disease (diseases when air collects outside of the alveoli)-Subcutaneous emphysema, pneumothorax, pneumomediastinum

111
Q

PC CMV Absolute Pressure

Increased Ti sec

A

Ti tot Increased

Te Decrease

I:E Increased

Pmean Increased

112
Q

PC CMV

Delta Pressures

Resistance Increased

A

Ti dyn Increase

113
Q

PC CMV Delta Pressure

Increased in PEEP

A

PIP Increased

Pplat Increased

Pmean Increased

114
Q

PaO2/FiO2 Ratio Definition

A

The ratio of partial pressure arterial oxygen and the fraction of inspired oxygen

Will help to determine the degree of any problems with how the lungs transfer oxygen to the blood

115
Q

Lung Protective Strategies-PEEP

A

Use PEEP cautiously in patients predisposed to alveolar rupture

Monitor for auto-PEEP

116
Q

Pressure vs. Volume Loop-Compliance

A

Compliance (imaginary line between start of inspiration and expiration)

Increased Compliance

  • Left Shift of the curve
  • Ex. Advanced Emphysema

Decreased Compliance

  • Decreased volume for pressure change
  • Will be a right shift of the curve
  • Ex. Pulmonary Fibrosis
117
Q

Where is the air in a Pneumomediastinum

A

Pneumomediastinum is when air collect into the mediastinum

118
Q

What is Vol %

A

Vol% is equal to ml O2/ 100 ml of blood

The amount of O2 in mls that is in 100 ml of blood

119
Q

VD/VT

A

The ratio of physiological deadspace to tidal volume

Normal VD/VT = 0.2-0.4

ICU common to be >0.70

>0.60, patient is unlikely to sustain spontaneous ventilation

VD/ VT = (PaCO2 - PECO2) / PaCO2

When CO2 goes up, pH will go down

For end tidal CO2 (PaCO2) which DOES NOT EQUAL PeCO2 which is the total amoutn of CO2 removed in one minute

PeCO2 will be given whenever we have to calculate deadspace

120
Q

PPV and the Liver

A

Impaired liver function 2° to decreased CO

PEEP has more impact on hepatic blood flow than PPV (PIP)does

121
Q

Where is the air in a Interstitial emphysema

A

Interstitial emphysema is when air collects in the lung supportive tissue known as pulmonary interstitium

122
Q

PC CMV Pressure Control Delta

Decreased PC

A

PIP Decrease

Pplat Decrease

Vt Decrease

Ve Decrease

Pmean Decrease

123
Q

Some results from an IPPA will require an action before a complete assessment can be completed

A
  • Tactile Fremitus and Crackles on Auscultation
    • Complete suctioning
  • High WOB
    • Adjust ventilator settings
124
Q

When a wedge pressure is higher the 18 what are we concerned about

A

When a wedge pressure is higher the 18 non cardiogenic pulmonary edema is likely to occur

125
Q

P(A-a) Normals

A

In a healthy pt. 21% O2 (room air) will produce a gradient of 5-15 mmHg (10-20 in elderly)

Normal A-a gradient=Age divided by 4 plus 4

Ex. A 40 year year old should have an A-a gradient of less than 14

100% O2 gradient is 100-150 mmHg

The normal range will change depends on how much oxygen the patient is on. This means that the value of using A-a calculation for determining oxygenation will decrease as the patient is on an increased FiO2 (most useful when on room air)

126
Q

Non-Patient Assessment-Suction Equipment

A
  • Reason for Changing Open Suction Catheter
    • Soiled
    • Faulty Valve
    • Sticky Catheter
    • Cutting of Sleeve
    • Faulty Instill Pot
  • Suction Equipment Changed
    • Yankuer
    • Yankuer Holder
    • Closed Suction Catheter
    • Suction Tubing
    • Canister Liner
127
Q

Auto PEEP

A

Extrinsic PEEP (= PEEPext = PEEPset)

  • Directly set on the vent

AutoPEEP or Intrinsic PEEP (= PEEPauto = PEEPint)

  • Cannot be determined by simple observation of the ventilatory pressures; can be determined to be present through inspection of the expiratory flow waveform
  • Requires an expiratory pause maneuver to measure (i.e. quantify)

Total PEEP (PEEPtot)

  • Reflects the total pressure in lung at end expiration

PEEPtot= PEEPext + PEEPauto

128
Q

Upper Inflection Point

A

upper inflection point = maximum setting for peak airway pressure

Has been proposed as a way to detect overdistention in the lungs, but this approach appears to be too simplistic as other parts of the lungs will already be over distended by the prior to reaching this point

‘Beak’ or ‘duckbill’=increase in airway pressure without any appreciable increase in volume

129
Q

Shunt: QS/QT Calculation

A

Qs/Qt= (CcO2-CaO2)/(CCo2-CvO2)

Where:

Qs = Pulmonary Physiologic Shunt (mL/min)

Qt = Cardiac Output (mL/min)

CCO2 = End-pulmonary-capillary Oxygen Content

CaO2 = Arterial oxygen content

CVO2 = Mixed Venous Oxygen Content

130
Q

Alveolar Air Oxygen Difference P(A-a)O2

A

This is a measure of the difference between the alveolar concentration of oxygen and the arterial concentration of oxygen

Will be used to help diagnose the source of hypoxemia and whether it is an intrapulmonary or extrapulmonary problem

Will help to assess the intgreity of the alveolar capillary unit

131
Q

Ventilator-Induced Injury Categories

A

Ventilator-Induced Injury can be divided into the following categories

  • Barotrauma
  • Volutrauma
  • Atelectrauma
  • Biotrauma
  • Oxygen Toxicity
132
Q

Time Constant

A

The time required to inflate (or deflate) a lung region

Complete filling requires 5 time constants

1 TC = 63%

2 TC = 86%

3 TC = 95%

In a pressure-controlled breath can be determined by the time it takes for equilibration to occur

Time Constant= Resiatance x Compliance

133
Q

PPV and CVS- Pt. Most at Risk

A

Most people will not be affected by this as the body will be able to compensate it is the septic, spinal injury patient that will be very problematic as we exceed the body’s capacity to compensate

Hemodynamically unstable patients (low BP etc.)

Patients with high lung compliance or low thoracic compliance (as transmission of the positive pressure to the thoracic space is greatest in these patients)

Worst case is a COPD pt. (higher lung compliance) with low thoracic compliance

134
Q

PC CMV Delta Pressure

Increased Rate

A

Ve Increase

Te Decrease

I:E Increase

Pmean Increase

135
Q

How Can the Pressure versus Volume Loop Be Measured

A

Can be measured as a dynamic or static technique

Dynamic: Requires a square inspiratory wave form to interpret – constant flow and no inspiratory pause

Static: Requires paralysis and measures of pressure with small incremental in volume

136
Q

Shunt: QS/QT

A

The shunt equation looks at the extent to which venous blood bypasses the capillaries (oxygenation) of the lungs

Increased if pulmonary venous admixture occurs (mixed venous blood exits A/C membrane unchanged)

137
Q

Alveolar- Air Oxygen Difference

A

Abbreviation: P(A-a)O2

Description: A measure of the difference between the alveolar concentration of oxygen and the arterial concentration of oxygen

Normal: Age divided by 4 plus 4

Calculation: PAO2 - PaO2

138
Q

Bronchopulmonary Hygiene

A

When assessing bronchopulmonary hygiene we need to look for

  • Color
  • Consistency
  • Tolerance by the patient
  • Cough
    • Spontaneous
    • With Stimulation
    • Not Present
  • Assess for Trends
  • Total passes of suctioning needed
139
Q

Dynamic vs. Static Compliance

A

Dynamic Compliance: Done during dynamic conditions (i.e. airflow), thus is impacted by Raw! Not too useful clinically.

Cdyn = VTeff/ (PIP - PEEPtot)

Static Compliance: Done during static conditions (i.e. no airflow), thus is a reflection of compliance only!

Cstat = VTeff/ (Pplat - PEEPtot)

140
Q

At the core of it what is ABGs measuring

A

Gas Exchange

141
Q

Oral and Trach Care

A

Oral and trach care can and often is done at the same time

142
Q

Non-Patient Assessment-Airway Equipment

A
  • Bedside Respiratory Safety Equipment
  • Manual Resuscitator
  • Masks
  • Airway
  • Airway
  • PEEP Valve
  • Trach Bag
  • Oxygen Tank
  • Wire Cutters
  • Intubation Supplies
  • Cricothyrotomy Tray
143
Q

PC CMV Pressure Control Absolute

Increased PC

A

PIP Increased

Pplat Increased

Vt Increased

Ve Increased

Pmean Increased

144
Q

Pressure vs. Volume Loop

A

A graphical representation of the relationship between pressure and volume during inspiration and expiration

Spontaneous breaths go clockwise and positive pressure go counter clockwise

In pressure control or PS the loop is almost square because of pressure limiting during inspiration

Bottom of loop is either 0 or PEEP level

Top of loop = PIP

145
Q

Disorders that Increase Resistance

A

Small ETT, plug in ETT, biting on ETT

Increased bronchospasm, mucosal edema, secretions, and/or airway obstruction

Increased inspiratory gas flow rate

146
Q

VC CMV Increased Insp. Pause

A

Titotal Increase

Te Decrease

I:E Increase

Pmean Increases

147
Q

PC CMV Pressure Control Absolute

Decreased PC

A

PIP Decrease

Pplat Decrease

Vt Decrease

Ve Decrease

Pmean Decrease

148
Q

Minute Ventilation

A

VE

Will typically be monitored by the ventilator

VE=RR x Vt

149
Q

Pressure Volume Loop-Leaks or Air Trapping

A

Loop won’t meet the bottom

150
Q

Resistance

A

The frictional resistance to gas flow

Varies; is dependant on the driving pressure

Changes throughout inspiration and expiration thus, most commonly, and more simply, calculated during constant flow (ie. VCV)

Normally 1 to 2 cmH2O/L/sec

Intubated, probably 5 to 10 cmH2O/L/sec or more

Raw = (PIP – Pplat) / flow

Transwairway Pressure is (Pm – Palv)

151
Q

Disorders that Result in Decreased Compliance

A

Decreased Lung Compliance

  • Atelectasis, pneumonia, pulmonary edema, ALI/ARDS, pneumothorax, fibrosis, bronchial intubation

Decreased Thoracic Compliance

  • Obesity, ascites, chest wall deformity
152
Q

Difference between hypoxemia and hypoxia?

A

Hypoxemia is defined as a condition where arterial oxygen tension (Pao2) is below normal (normal Pao2 = 80–100mmHg).

Hypoxia is defined as the failure of oxygenation at the tissue level.

Generally, the presence of hypoxemia suggests hypoxia.

However, hypoxia may not be present in patients with hypoxemia if the patient compensates for a low Pao2 by increasing oxygen delivery. This is typically achieved by increasing cardiac output or decreasing tissue oxygen consumption.

Conversely, patients who are not hypoxemic may be hypoxic if oxygen delivery to tissues is impaired or if tissues are unable to use oxygen effectively.

Nevertheless, hypoxemia is by far the most common cause of tissue hypoxia.

153
Q

PC CMV Delta Pressure

Decrease in PEEP

A

PIP Decrease

Pplat Decrease

Pmean Decrease

154
Q

Disorders that Decrease Resistance

A

Bronchodilator administration

Suction and airway care

Use of lower inspiratory gas flow rate

155
Q

PPV and Metabolism

A
  • PPV takes over all or part of the WOB
  • Decreased O2 consumption and CO2 production by respiratory muscles but…
    • Hypermetabolism is associated with major illnesses/surgical procedures
      • Proper nutritional intake for patient’s size and illness; malnutrition a major concern
        • But we now have a tube down their throat blocking their ability to swallow making it more difficult to provide nutrition
        • Morphine will also slow down time to move food throughout the body making even more of a problem because the body needs more nutrients
156
Q

Oxygen Saturation of 90%

A

This is the minimum oxygen concentration that is needed to provide enough oxygen to prevent ischemia in the tissues

Once the O2 sat falls below 90%, the PaO2 drops quickly into the dangerously hypoxic range as fewer and fewer oxygen molecules are bound to Hgb.

We want to try to keep O2 saturation above 90%.

157
Q

Pressure vs. Volume Loop-WOB

A

Line drawn down middle of loop

On inspiration (area to right side of line)

On expiration (area to left side of line)

158
Q

When we are trying to improve oxygenation in ventilation in a pt. what can we do?

A

1) Increase PEEP
2) Increase FiO2
3) Increase Titotal

  • Increase mean airway pressure by increasing the I:E ratio
  • 1:1 is a higher I:E ration compared to 1:4 (think of it as 1/1 and ¼ and then then answer for 1:1 is 1 and for 1:4 is 0.25)
159
Q

PRVC Increased Compliance

A

PIP Decreases

Pplat Decreases

Tidyn Increases

Pmean Decreases

160
Q

PRVC Decreased Compliance

A

PIP Increases

Pplat Increases

Tidyn Decreases

Pmean Increases

161
Q

PRVC Decreased Compliance

A

Decreased Tidyn

162
Q

Aspects of WOB

A
  • Mechanical
    • Elastic and non-elastic work
  • Metabolic
    • Oxygen consumption
  • Relationship of work, rate and depth of breathing to muscle fatigue
  • Readiness to Wean from ventilator
163
Q

WOB- Inspiration

A

Associated with the amount of negtaive pleural pressure that is generated during a ventilatory effort

2/3 Due to Elastic Resistance

1/3 due to Non-Elastic Resistance

164
Q

WOB- Expiration

A

Normally passive

High Raw may need more expiratory muscle wokr

165
Q

Directly Measuring WOB

A

Uses an esophageal pressure monitor to reflect intrapelural pressure changes

The pressure time product is calculated from the area underneath the generated curve

PTP is a simpler measure than WOB and will parelle the change in effort and VO2 cost of breathing

166
Q

Pressure Volume Curve

A

Will be narrow and long in restrictive diseases

Will be wide in obstructive lung diseases

167
Q

WOB in Normal States

A

We will try to breath while using a minimal amount of work

A normal healthy young adult will have a Vt of 500-600ml

168
Q

Work of Breathing in Diseased States

A

Fast breathing will produce high flow rates which increases Raw

Large tidal volumes will require a strech in the lung and increase elastic work

Both of the above will increase WOB but the body will adapt a RR and Vt in mimize WOB

169
Q

Oxygen Cost of Breathing

A

The amount of O2 that is consumed by the ventilatory muscles (VO2R) will give and estimate of respiratory effort

Noral is 2-5% of total VO2

Upon dsypnea this can increase to 30% and even up to 10 times normal amount in COPD. Will also increase with obseity, fibrosis and congestive failure

Measures by (not commonly used)

VO2R=VO2 in active breathing-VO2 apnea

170
Q

Patient-Ventilator Synchroncy

A

The compatability between the patient bretahing effort and the ventilator

Important to consider: Mode, Phase Variables

171
Q

Patient-Ventilator Synchroncy-Triggering

A

Can be seen on patient assessment as well

on the monitor it will look like random swiggly lines in between breath

172
Q

Patient-Ventilator Synchroncy- Limit Varible

A

In volume control if the limit variable is not set properly we may not be meeting inspiratory demands of the patient and instead of a straight steady increase on the pressure waveform there will and a depressed upwards curve

In pressure control the patient will be able to compenstate for the limit varaible through varying flow and volumes

173
Q

Patient-Ventilator Synchroncy- Time Cycling

A

Ideally we want to see pressure equilibrium at the end of inspiration in pressure limited mechanical breaths

174
Q

Patient-Ventilator Synchroncy- Flow Cycling

A

Many vents will allow for the adjustment of the flow cycle level

Tailor to pt, and situation

175
Q

Pulse Oximetry

A

Non-invasive measurement of arterial oxygen saturation

An oximeter is an instrument that measures the amount of light absorded/ transmited through the blood

Based on photoplethysmography and spectrophotometry

176
Q

Photoplethysmography

A

Uses light absorption to detect tiny volume changes that occur in the tissues due to blood pulsing in the vascular beds

The amount of light that is absorbed is proportional to the amount of blood flow

Maximum absorption during systols and minimum during diastole

So this detects perfusion/ pulsatile blood flow

177
Q

Spectrophotometry

A

Is the science taht uses light wavelengths to measure light absorption through a substance in this case blood

There are two wavelengths that are used in pulse oximetry: Red light (660nm) and infrade light (940 nm)

178
Q

Lambert Beer Law

A

Basis of spectrophotometry

The amount of light a substance will absorb depends on the amount of substance and on the concentration of the substances in the sample.

As the concentration of a substance increase so will the light absorded

179
Q

Pulse Oximeter-The Oximeter

A

Designed to measure either transmitted or reflected light

Uses LEDs to send the light wavelengths

Has a photodetector to measure the transmitted (or reflected) light

180
Q

Appropraite Oximtery Sites

A

Finger, Toe

Ear

Bridge of Nose

Forehead

Infant: Across the foot or hand

181
Q

Pulse Oximeter-Displayed Values

A

The displayed value: SpO2

This is called a functional saturation (not to be confused with fractional saturation)

Functional saturation is the ratio of HbO2 to the total Hb available for binding with O2

Functional saturation does not take into account the dysfunctional hemoglobin’s, like HbCO or metHb

182
Q

Pulse Oximetery Accuracy

A

+/- 3-5%

You can have false high readings when SpO2 is <80%

The lower the sat the more likely it will read to high which is why it is important to compare against blood gas

183
Q

Factors the affect pulse oximeter accuracy

A

Motion

Low perfusion

External lights

False nails/ Nail polish

Wrong type of sensor

Incorrect placement (too tight or loose)

Dysfunctional Hb, anemia

Vascular dyes

184
Q

How to Trouble Accuracy with Pulse Oximetry

A

•Motion interference

Low perfusion

Dysfunctional Hb present

Anemia

Venous pulsation

Ambient light interference

Electrical interference

Optical cross talk

Optical shunt

185
Q

Masimo Radial 7

A

Uses different wavelengths to calculate and display

SpO2

SpMet- Altered shape of hemoglobin making it difficult to bind to an incorrect number of Fe and can be caused by tropical anaesthetics (Lidocaine)

SpCO

SpHb

SpOC

186
Q

Venous Oximetry

A

Combines fibre-optics with an indwelling catheter to allow for continuous monitoring of

SvO2 (via PAC)

SjvO2 (via catheterization of the jugular vein)

Based on reflectance spectrophotometry

187
Q

Co-Oximetry

A

=Hemoximetry

Based on the principal that different forms of Hb absords light differently at different wavelengths

Uses four (or more) wavelengths to measure Hb, HbO2, HbCO, and MetHb

188
Q

Co-Oximetry Measurement

A

The saturation we see from a co-oximeter is the fraction saturation

Fractional Saturation: Ratio of Hb bound with O2 compared to the total amount of Hb present

Total Hb includes HbO2, Hb, and dsyfunction Hb

189
Q

Capnography

A

Capometry: Measurement of CO2 in exhaled gases; provides digital display of EtCO2 value (i.e. a number)

Capnography is a graphic display of CO2 level as they change dueing breathing

190
Q

Capnography Methods

A

Infraded absorption spectroscopy is the most common method

Can be main stream (directly in line with flow) which is more accurate. Or side stream which is a line coming off the flow tubing and can easily get damaged or filled with secretions or fluid

191
Q

Clinical Relevance of Capnography

A

End tidal CO2 is closely related to PaCO2

A normal PetCO2 averages 3-5 mmHg less than PaCO2

A PaCO2 greater than ETCO2 is indicative of a V/Q mismatch

Can help in confirmation of ETT placement and the effectiveness of CPR

A sudden increase in the P(a-et)CO2 can indicate a pulmonary embolus.

192
Q

Suptum Culture and Sensitivity

A

Culture: Determines the presence and identification of bacteria or fungi in the sputum

Sensitivity: Determines which antibotics the culture is sensitive too and will be the most effective

193
Q

Bronchoalveolar Lavage (BAL)

A

A bronchoscope is advanced into a lung segment and wedged in the bonchus

Sterile saline is flushed into the segment and then suctioned back up thru the bronchoscope

The sample is collected in a sterile container and is analyzed via a culture and sputum

Can also help determine if an inflammatory process is under way due to the presence of neutrophils, and can somtimes detect food particles is aspiration has occured

194
Q

CT (Computed Tomography)

A

Takes on multiple cross sectional images of the chest (or other) about 1 cm apart

Helical CT take these images very quickly and can allow for an angiography to occur when a contrast dye is administered intravascularly

195
Q

V/Q Scan

A

The perfusion scan is obtained by injecting radiolabeled albulmin intravanesously

The ventilation scan is obtained by having the patient breathe in a radiolabled gas

A gamma camera collects the images

196
Q

Lung Mapping

A

Provide imagining (a “map”) of the distribution of ventilation, allowing localization and quantification of areas of injury

“Quiet” regions are those without ventilation and will not be seen in the scan

Is dynamic monitoring and can provoke continuous monitoring or a spot check

Can help to evaulet optimal PEEP levels and the effect of recruitment maneuver, and other aspects of ventilation

197
Q

What are the two Methods of Lung Mapping

A

1) Electrical Impedance Tomography
2) Acoustic Respiratory Monitoring (ARM)

198
Q

Lung Mapping-Electrical Impedance Tomography

A

Uses 16-32 electrodes placed around the chest

Impedance between the electrodes is measured

A video reconstruction of ventilation will be created

199
Q

Lung Mapping-Acoustic Respirtory Monitoring

A

Uses a series of stethscopes placed around the chest

Ventilation map is created from the sounds

200
Q

Chest Tubes

A

Chest tubes are used to help manage pleural diseases

There are a range of sizes

Will typically be connected to either a Heimlich valve or thoracic drainage unit

CXRs are helpful in assessing location and depth for insertion, as well as resolution of the original problem

Percussion and auscultation can be helpful in assessing the effectiveness of this therapy

An assessment of the dressing and/or site can reveal onset of infection and/or air leaks

201
Q

Passive Humidification

A

Most common method for our adult patients

Achieved through the use of an HME or HMEF

202
Q

Active Humidity

A

Heated humidifier and heated wires in the circuit

Indications

  • Bloody secretions
  • Thick, tenacious sputum
  • Hypothermia (core temp <32 °C)
  • Burn patients
  • Patients where HME contraindicated
    • Neonates; small peds
  • High MV or large leaks leakscausing Vte< 70% of inhaled
203
Q

VAP

A

Ventilator-associated pneumonias are caused by the micro-aspiration of the micro-organisms in oral and gastric secretions

30-Cuff Pressureto keep secretions out (25-30)

30-HOB at 30 degree angle

30-Suction on EVAC tube

204
Q

Reducing VAP

A

Perform gentle suctioning

Minimize circuit changes

Use MDI’s (not SVNs) for med delivery to intubated patients

Daily SATs and SBTs (to reduce duration of intubation)

Use NIV when possible

Perform oral hygiene every 4 hours at minimum

Oral, not nasal, gastric tubes

Measuring gastric residual volumes

Many institutions have a “ventilator bundle” where two or more strategies to reduce nosocomial pneumonia and VAP are combined.

205
Q

ALI and ARDS Ventilator Strategy

A

The low compliance necessitates smaller VTto keep plateau pressures < 30 cmH2O

VT in the 4-6 mL/kg range

PEEP is important to maintain recruitment

High levels of PEEP may be indicated

Can use the static (or low-flow) V-P curve to help determine

ABG targets

  • The low VT often results in a permissive hypercapniastrategy
  • PaCO2 allowed to climb as long as pH > 7.25
  • Minimal FiO2 to keep SpO2 > 90% (typically)
206
Q

TBI Ventilator Strategy

A
  • (Typical) ABG targets:
    • Low-normal PaCO2 (35-40 mmHg)
    • High-normal pH (7.40-7.45)
    • Slightly vasoconstricts vessels to the brain resulting in decreased ICP
    • PaO2 80-120 mmHg
  • Ventilator settings:
    • Typically normal lungs so follow settings for normal lungs
207
Q

Obstructive Disorders Ventilator Strategies

A

COPD vs Asthma

  • Problems with airway resistance, but by different mechanisms
  • Asthma: bronchoconstriction; narrowed airway lumen
    • Maximize time
    • Push breath in fast and give it time to exhale (increase flow or Ti)
  • COPD: the high lung compliance results in “floppy” airways and airway collapse on forced exhalation
    • Inhalation is easy and exhalation is difficult
  • Both have high time constants resulting in prolonged expiration time required; auto PEEP is common
  • Ventilator settings:
    • Main goal is to maximize expiratory time in order to decrease the auto PEEP
208
Q

Criteria for D/C of Ventilatory Support:

A

Original reason for mechanical ventilation is resolved

Patient has stable vital signs/hemodynamics

Patient should be able to manage WOB on their own

This is where weaning parameters help

209
Q

Criteria for extubation:

A

Able to maintain their airway

Good LOC or has TT in place

Cuff leak is present

Is able to protect their a/w

Presence of cough and gag reflexes

Is able to manage their secretions

Look at sxn history, effectiveness of cough

210
Q

Weaning Parameters

A

Spontaneous VT4-6 mL/kg

*RR < 35 bpm

*VC > 10 mL/kg

*NIP (MIP) > 20 cmH2O

f/VT< 105 (also known as the RSBI or Tobin score)

MV < 12-15 LPM

So this is what we used to assess know there are also other things we look for as studies have shown that these weaning parameters are not a good indice of how well they will wean

211
Q

Trends in Weaning

A

Using weaning parameters alone are not good predictors of succesful weaning and the best parameter in the SBT

Studies have shown that 75% of patients need NO weaning

Weaning should take on the form of screening for readiness for discontinuation from mechanical ventilation rather than an approach that steadily reduces ventilatory support

Still need to balance FVS vs. PVS until SBT is passed

212
Q

Spontaneous Breathing Trial

A

Ideall done once daily in combination with a SAT

Patient will be placed on a mode that provides minimal assisstance (PSV, CPAP, T-piece)

Can assess the patient’s spontaneous breathing from 30 min up to 120 min

The longer they have been ventilated, the longer the SBT

Tobin Score and WOB assessed throughout

213
Q

Ventilator Dependance

A

Respiratory Factors-Increased ventilatorydemand, muscle atrophy, abnormal lung mechanics (R or C)

Cardiovascular Factors-MI, arrhythmias, hemodynamic instability

Neurological Factors-Decreased drive to breathe, impaired neurotransmission

Psychological Factors-Fear of removal of life support, anxiety, stress, depression, sleep deprivation

214
Q

MDI

A

Most common; typically used to deliver bronchodilators and ICS

Requires a special actuator to adapt the MDI to the ventilator circuit (ideally has a chamber to increase aerosol delivery to lung)

Requires timing of the actuation with inspiration

Often the dose is adjusted due to “loss” to the circuit

215
Q

Nebulizers

A

Nebulization during inspiration only results in greater delivery of the drug

If the nebulizer is external to the vent it can add to the delivered tidal volume and interfere with triggering

These disadvantages and the increased risk of contamination mean we typically use MDIs

Inhaled antibiotics (e.g. Gentamicin, vancomycin) or mucolytics(i.e. drugs not available in MDI) may be given via nebulized treatment

216
Q

Nitric Oxide (NO)

A

A colourless, odorless gas

It is produced endogenously in vascular endothelial cells and is a potent vasodilator

Because it is inhaled it is selective to the pulmonary system and thus is a potent pulmonary vasodilator

Administered via the INOvent

T’s in NO, servo-controls and analyzes levels

Common Uses-ARDS, Pulmonary hypertension, Neonates (PPHN, congenital heart defects)

217
Q

Effects of Nitric Oxide

A

The pulmonary vasodilation results in:

Decreased PVR

Decreased pulmonary artery pressures

Decreased intrapulmonary shunting

Better V/Q matching as NO increases blood flow only to ventilatedalveoli by relaxing the smooth muscles of the capillaries supplying these alveoli

Improved oxygenation

Effects are limited to the pulmonary circulation because after diffusing into the capillaries NO immediately binds to hemoglobin

Winter 2018-Patient Assessment (7 decks)

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