RESPIRATORY PATHOPHYSIOLOGY modules 15-23 Flashcards

1
Q

List the monitors of venous air embolism from most sensitive to least

A

TEE
Precordial doppler
EtCO2
CVP

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2
Q

List the positions that increase the risk of venous air embolism from greatest to least

A

Sitting
Supine
Prone
Lateral

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3
Q

Signs and symptoms of venous air embolism

A
Air on TEE
Mill wheel murmur on precordial doppler
Decreased EtCo2
HoTN
Dysrhythmias
Hypoxia
Cyanosis
CV collapse
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4
Q

What is the treatment for venous air embolism

A
100% FiO2
Flood the surgical field
D/C insufflation
Left lateral decubitus positioning
Air aspiration via CVC
Hemodynamic support
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5
Q

How does a venous air embolism occur

A

Air is entrained into bloodstream via an open vessel above the level of the heart

Increased risk in spontaneously ventilating patients

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6
Q

What are consequences of air trapped in the pulmonary circulation

A
  1. Increased PA pressure
  2. Increased RV stroke work index
  3. RV failure
  4. Decreased pulmonary venous return
  5. Decreased LV preload
  6. Decreased CO
  7. Asystole and CV collapse
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7
Q

How does air trapped in the pulmonary circulation affect the left side of the heart?

A
  1. Decreases LV preload
  2. Decreases CO
  3. Leads to asystole and CV collapse
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8
Q

What interventions reduce pulmonary vascular resistance

A

Hyperventilation
Nitric oxide
NTG

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9
Q

What interventions increase pulmonary vascular resistance (5)

A
Hypoxia
Hypercarbia
N2O
hypothermia
PEEP
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10
Q

What is PAP in pulmonary HTN

A

PAP > 25 mmHg

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11
Q

What pathophysiologic alterations increase pulmonary vascular resistance

A

Increased vascular smooth muscle tone
Vascular cell proliferation
Pulmonary thrombi

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12
Q

What effects can pulmonary HTN have on RV workload

A

Increases

Progression to RV failure (cor pulmonale)

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13
Q

Anesthetic considerations for patients with pulmonary HTN

A
  1. Give medications for PVR reduction preoperatively
  2. Preload dependent d/t fixed CO
  3. Aggressive HoTN treatment
  4. Epidural over spinal anesthesia
  5. Inhaled nitric oxide
  6. Jet ventilation
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14
Q

Describe the process of LV preload dependence in the patient with pulmonary HTN

A

Increased RV afterload causes RV dilation, hypertrophy and systolic failure
Decreased output from RV
HoTN d/t decreased LV preload
Intraventricular septum bowing into LV compromises filling

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15
Q

How does tricuspid regurgitation occur d/t pulmonary htn

A

Increased RV volume at end diastole d/t decreased RV stroke volume
Stretches tricuspid annulus leading to regurg

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16
Q

Causes of pulmonary HTN

A
COPD
Hypoxemia & Hypercarbia
left heart dysfunction
MV disease
CHD
Connective tissue disorders
Thromboembolism
Portal HTN
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17
Q

What is the normal pulmonary vascular resistance

A

150-250 dynes-sec-cm5

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18
Q

Equation for PVR

A

PVR = ([mean PAP - PAOP]/CO x 80)

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19
Q

What can increase pulmonary vascular resistance

A
Hypoxemia
Hypercarbia
Acidosis
SNS stimulation 
Pain
Hypothermia
Increased intrathoracic pressure
Mechanical ventilation
PEEP
Atelectasis
N2O
Ketamine
Desflurane
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20
Q

Anesthetics that increase pulmonary vascular resistance

A

N2O
Ketamine
Desflurane

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21
Q

Drugs that decrease pulmonary vascular resistance

A
Nitric oxide
NTG
PDE inhibitors
PGE1/2
CCB
ACE inhibitors
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22
Q

What can decrease pulmonary vascular resistance

A
Increased PaO2
Hypocarbia
Alkalosis
Decreased intrathoracic pressure
Spontaneous ventilation
Avoid coughing/straining
NO
NTG
PDE inhibitors
PGE1/2
CCB
ACE-i
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23
Q

How is preload managed in the patient with pulmonary HTN

A

Requires adequate preload, therefore treat HoTN aggressively

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24
Q

In a gravid patient with pulmonary HTN, what are the CV effects of uterine contractions and the treatment

A

Effects = Too much preload, PA HTN, RV dysfunction

Treatment = NTG

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25
Q

Hgb has an affinity for carbon monoxide that is ___ times greater than O2

A

200 times

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26
Q

Carbon monoxide shifts the oxyhemoglobin dissociation curve which direction

A

Left

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27
Q

What is the treatment for carboxyhemoglobinemia?

A

Supplemental O2

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28
Q

How does soda lime affect carbon monoxide levels

A

If it is desiccated the risk of CO formation is greatest

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29
Q

What type of metabolism is a result of carboxyhemaglobinemia

A

Anaerobic metabolism because O2 is not released at tissues

This leads to metabolic acidosis due to impaired oxidative phosphorylation and reduced ATP production

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30
Q

Hyperbaric O2 is indicated if CoHgb exceeds what percent of total hgb?

A

25%

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31
Q

When treating CoHgb, 100% O2 should be administered until the CoHgb is less than __%

A

5%

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32
Q
What are strong indications for mechanical ventilation 
VC \_\_
Inspiratory force \_\_
PaO2 \_\_
A-a gradient \_\_
PaCO2 \_\_
RR \_\_
A
VC <15 mL/kg
Inspiratory force <25 cmH2O
PaO2 <200 mmHg on 100% FiO2
A-a gradient >450 mmHg on 100% FiO2
PaCO2 >60 mmHg
RR >40 or <6 bpm
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33
Q

What drugs can be administered via an ETT

A
NAVEL
Narcan
Atropine
Vasopressin
Epinephrine
Lidocaine
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34
Q

What is the normal A-a gradient

A

<10 - 15 mmHg

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35
Q

What are the benefits of endotracheal intubation

A
  1. Patent airway
  2. Controlled ventilation
  3. Ventilate with high airway pressure
  4. Secure airway
  5. Removal of secretions
  6. Lung isolation
  7. Medication administration
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36
Q

What are the best predictors of postop pulmonary complications for patient undergoing pulmonary surgery
FEV1 __
DLCO __
VO2 max __

A

FEV1 <40% predicted
DLCO <40% predicted
VO2 max <15 mL/kg/min

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37
Q

What are the 3 categories of predictors of postop pulmonary complications following pulmonary surgery.

A
Lung parenchymal function (gas exchange)
Respiratory mechanics (airflow)
Cardiopulmonary reserve
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38
Q

If a VO2 max is not available to assess postop pulmonary complications, what question can give similar information

A

Ask if patient can climb 2 flights of steps

If no, the patient is at risk

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39
Q

What are the 3 categories for absolute indications for OLV

A

Isolation to avoid CONTAMINATION
Control of ventilation distribution
Unilateral bronchopulmonary lavage

40
Q

What are absolute indications for OLV

A
Infection
Massive hemorrhage
Bronchopleural fistula
Surgical opening of major airway
Large unilateral cyst/bullae
Hypoxemia d/t lung dz
Pulmonary alveolar proteinosis
41
Q

What high priority relative indications for OLV and surgical exposure

A
Thoracic aortic aneurysm
Pneumonectomy
Thoracoscopy
Upper lobectomy
Mediastinal exposure
42
Q

DLT size for males and females based on height

A

Female:
<160 cm = 35 french
>160 cm = 37 french

Male:
<170 cm = 39 french
>170 cm = 41 french

43
Q

Approximate DLT insertion depth for males and females

A
Males = ~29 cm
Females = ~27 cm
44
Q

What data can aid in choosing the proper DLT size

A

CXR and CT to assess for abnormalities in tracheobronchial anatomy

45
Q

At what age do we use DLT for pediatric patients

A

at 8 years

46
Q

Why are DLT not manufactured for pediatric patients <8 yo

A

Because the lumens would be so narrow that resistance to airflow would be incredibly high

47
Q

What are the options for lung isolation in children <8 years

A

Bronchial blocker

Single lumen ETT in mainstem bronchus

48
Q

What is the cause of shunt during OLV.

What does this cause

A

Mixing blood from non-dependent (non-ventilated) lung and dependent (ventilated) lung
Causes hypoxemia

49
Q

Which lung is better ventilated in the lateral decubitus position

A

Non-dependent lung (which is not ventilated)

50
Q

Which lung is better perfused in the lateral decubitus position

A

The dependent (ventilated) lung

51
Q

What is the cause of V/Q mismatch in the lateral decubitus position for OLV

A

The non-dependent lung is better ventilated but poorly perfused and it is also the non-ventilated lung

52
Q
Mechanical ventilation considerations for OLV initiation
FiO2 \_\_
Vt \_\_
RR \_\_
PEEP \_\_
A

FiO2 100%
Vt 6-8 mL/kg ibw
RR 12-15 bp,
PEEP 5-10 cmH2O

53
Q

What maneuver is helpful before initiating OLV

A

Alveolar recruitment maneuver

54
Q

How can the I:E ratio be adjusted to improve OLV

A

Adjust if the patient has an expiratory air flow limitation

i.e. increase I:E to allow for full exhalation

55
Q

What type of anesthetic may be beneficial for OLV

A

TIV because volatile anesthetics can inhibit the HPV response

56
Q

What steps are taken to address hypoxemia in OLV

A
  1. 100% FiO2
  2. Confirm position of DLT w/ fiber
  3. r/o physiologic causes (mucus plug, PTX etc)
  4. Apply CPAP to NON-dependent lung
  5. PEEP 5-10 cm H2O to DEPENDENT lung
57
Q

What steps may be taken if initial efforts to address hypoxemia are unsuccessful

A
  1. Intermittently reinflate non-dependent lung
  2. Ligate pulmonary artery
  3. Eliminate drugs that inhibit HPV response
58
Q

What is the result of the DLT being in too far

A

Upper lobe is NOT ventilated, increasing hypoxemia

59
Q

What is the result of DLT not being deep enough

A

Failure to achieve lung separation

BS bilateral

60
Q

What is the result of DLT in the wrong bronchus

A

The wrong lung is collapsed

61
Q

How does hypoxemia affect the A-a gradient

A

INCREASES gradient

62
Q

How does PPV affect V/Q mismatch

A

PPV increases alveolar pressure and makes it part of West zone 1, increasing dead space

63
Q

What is seen when confirming DLT placement with a fiber bronchoscope

A
Tracheal lumen = incomplete C-rings open posteriorly
Blue cuff 
-in correct bronchus
-not herniating
Right bronchus has 3 takeoffs 
Left bronchus has 2 takeoffs
64
Q

Left-sided DLT confirmation by auscultation
Clamp TRACHEAL lumen with both cuffs inflate

Describe BS in each condition:
Correct
In too far (left)
In trachea
In too far (right)
A

Correct:
left = yes, right = no

In too far (left):
left = yes, right = no

In trachea:
left = yes, right = yes

In too far (right):
left = no, right = no

65
Q

Left-sided DLT confirmation by auscultation
Clamp BRONCHIAL lumen with both cuffs inflate

Describe BS in each condition
Correct
In too far (left)
In trachea
In too far (right)
A

Correct:
left = no, right = yes

In too far (left):
left = no, right = no

In trachea:
left = no, right = no

In too far (right)
left = no, right = no

66
Q

Left-sided DLT confirmation by auscultation
Clamp BRONCHIAL lumen and deflate cuff

Describe BS in each condition
Correct
In too far (left)
In trachea
In too far (right)
A

Correct
Left = yes, right = yes

In too far (left):
left = yes, right = no

In trachea:
left = yes, right = yes

In too far (right):
left = no, right = yes

67
Q

Steps for lung isolation with OLV

A
  1. Inflate bronchial cuff
  2. Clamp lumen distal to y-piece of operative lung
  3. Open lumen to operative side
  4. Adjust FiO2
  5. Vt 6 ml/kg to keep PIP20
  6. Adjust RR to maintain PaCO2 35-45
  7. Perform alveolar recruitment before OLV
  8. Check ABG
  9. Add PEEP
  10. Adjust I:E for COPD pts
  11. Limit volatile gas to <1.5 to prevent HPV impairment
68
Q

How does PEEP improve FRC in the OLV pt

A

It increases FRC by pushing the lung up the alveolar compliance curve

69
Q

Is hypoxemia during OLV more common during surgery on the right or left lung?

A

Right lung

There is less are for gas exchange when the left lung is the only one ventilated

70
Q

How do the DLT and bronchial blockers differ (5)

A
  1. BB cannot prevent contamination
  2. BB cannot ventilate isolated lung
  3. BB cannot suction
  4. BB can be used in peds <8 yo
  5. BB can be used with NT tubes
71
Q

Advantages of using a BB over DLT

A

Don’t need to be reintubated
Can be used with NT tubes
Can be used in kids <8 y

72
Q

Which lung is ventilated when using a bronchial blocker?

A

The lung on the opposite side of the BB

73
Q

What are the uses of the lumen in the BB

A
  1. Insufflating O2 into non-ventilated lung

2. Suctioning air (NOT secretions) from non-ventilated lung

74
Q

What are the 2 most common and serious complications of mediastinoscopy

A

Hemorrhage

PTX

75
Q

What is an absolute contraindication to mediastinoscopy

A

Prior mediastinoscopy

76
Q

Where should pulse oximetry and NIBP be placed when monitoring a patient having mediastinoscopy and why

A

Pulse ox = RUE
NIBP = LUE

pulse ox/a-line are on RUE. The waveform will dampen or disappear if the innominate artery is compressed during mediastinoscopy

77
Q

What are indications for tracheal resection

A
Tracheal stenosis
Tracheomalacia
Tumor
Vascular lesions
Congenital malformation
78
Q

A patient is 2 days s/p tracheal anastomosis and requires reintubation. What is the best technique and why

A

Use flexible fiberoptic bronchoscopy

Pts neck must maintain flexed position so extension for intubation is contraindicated

79
Q

Complications of mediastinoscopy include injury to which structures

A

Thoracic aorta = hemorrhage and bradycardia
Innominate artery = decreased carotid BF, decreased CBF
Trachea = airway obstruction
Thoracic duct = chylothorax
Phrenic/RLN = paresis

80
Q

What are 3 relative contraindications for mediastinoscopy

A
  1. Tracheal deviation
  2. Thoracic aortic aneurysm
  3. SVC obstruction
81
Q

What patient history considerations must be assessed prior to an anesthetic for mediastinoscopy

A
  1. Type of lung CA. Eaton-Lambert syndrome means sensitivity to SUX and ND-NMBD
  2. CV disease
  3. History of stroke
82
Q

During mediastinoscopy, what can result if the innominate artery is compressed?

A

Compromises right carotid and therefore cerebral blood flow

83
Q

Importance of proper IV access in patients undergoing mediastinoscopy

A

Large bore LE access helps avoid loss of fluids or blood through vascular injury

84
Q

You are pre-oping a patient for tracheal resection, what are important history and assessment considerations

A
  1. Are there airflow limitations
  2. Is there a CT to review
  3. Evaluate flow-volume loops
85
Q

What type of induction would be appropriate for a patient undergoing tracheal resection and why

A

Awake intubation or inhaled induction
Obstruction during induction can occur.
Must preserve spontaneous ventilation to prevent obstruction

86
Q

Which artery is at risk for compression during tracheal resection

A

Innominate (brachiocephalic) artery

87
Q

What lung protective methods are taken in mechanically ventilating a patient with ARDS

A
  1. Low Vt

2. PEEP

88
Q

What is the cause of ARDS

A

Inflammatory injury that leads to diffuse alveolar destruction

89
Q

What are 4 key pathophysiologic features of ARDS

A
  1. Protein-rich pulmonary edema
  2. Loss of surfactant
  3. Hyaline membrane formation
  4. Possible long-term lung injury
90
Q
Mechanical ventilator setting for a patient with ARDS
Setting \_\_
Vt \_\_
PEEP \_\_
Plateau pressure \_\_
RR \_\_
I:E \_\_
O2 goal \_\_
A
Setting = pressure control
Vt = 4-6 ml/kg ibw
PEEP = titrate to keep FiO2<50%
Plateau pressure <30 cmH2O
RR = 6 - 35 bpm
I:E = 1:1 - 1:3
O2 goal = PaO2 55-80 mmHg
91
Q

What is ARDS

A

A form of non-cardiogenic pulmonary edema

92
Q

What etiologies contribute to ARDS

A

Pulmonary causes:
PNA, COVID, aspiration, smoke inhalation injury, near-drowning

Extra-pulmonary causes:
SEPSIS, hematologic, trauma/shock, burns

93
Q

What are the 3 stages of ARDS

A

Exudative = initial injury and inflammatory cascade

Proliferative = pathophysiologic process continues but body is trying to heal itself

Fibrotic = changes that cause irreversible damage to lung architecture and pulmonary HTN

94
Q

How are PA pressures affected by cor pulmonale

A

They aren’t
PA pressures should be normal
Cor pulmonale is d/t pulmonary HTN not LV failure

95
Q

A patient in the PACU exhibits signs of recurarization despite reversal with neostigmine and glycopyrrolate. What patient assessment can contribute to impaired reversal

A

Hypoventilation

Respiratory acidosis potentiates NMB and reduces efficacy of anticholinesterase worsening hypoventilation

96
Q

Describe fluid management recommendations for patient undergoing pneumonectomy

A

Since pt is dependent on a single lung, it is best to limit crystalloid to replacement of volume deficit and maintenance requirement

Recommendations <3 L in 24 hours