Pulmonary - CCRN Flashcards
Which area of the brain controls respiration?
Medulla
Which part of the C-spine contains the phrenic nerve and therefore controls the diaphragm?
C 3,4,5
Describe the process of inspiration.
Diaphragm contracts, moves downward
Intrathoracic pressure decreases
Air flows in
O2 is exchanged at the alveolar/capillary bed
Describe expiration
Diaphragm relaxes (moves up)
Thoracic volume decreases
Intrathoracic pressure increases
Gas flows out
What factors/processes can change lung compliance?
Age - infants have increased lung compliance
Compliance decreased by:
Pulmonary edema
Pneumothorax
Atelectasis
Name 2 types of collapsed lungs and describe them.
Pneumothorax - puncture to pleural lining
Atelectasis - pleural lining intact, lung cannot expand
Causes and risk factors for a pneumothorax
-Trauma
-Spontaneously - part of the lung ruptures
More common with existing lung condition:
COPD, TB, pertussis, asthma, CF, chronic bronchitis, emphysema
Procedures - line insertion
Infection
Risk factors:
Being tall and thin
Previous hx of collapsed lung
Smoking
What are the causes of atelectasis?
Usually from a blockage of the airway:
Mucous, tumors, small objects
Can result from pressure outside the lungs
Fill in the blank:
Resistance is ______________ related to airway diameter.
Give examples
Resistance is INVERSELY related to airway diameter.
Increased in: Asthma, CF, BPD, bronchiolitis, increased secretions.
This causes a DECREASE in air that reaches the lungs.
What is BPD?
Inflammation and scarring of lung tissue during development.
Most common in premies.
Describe the affect fetal circulation has on the lungs.
In utero:
Increased pulmonary vascular resistance leads to decreased pulmonary blood flow.
On delivery the pulmonary vascular resistance drops to allow for increased pulmonary blood flow.
Explain how to look at V/Q as a ratio.
Think ventilation first.
1:1 is normal.
The lower number is the problem!
High/low refers to the first number’s relationship to the second number.
What is ventilation?
Ventilation (V)
How fast O2 and CO2 are exchanged
What is perfusion?
Perfusion (Q)
The speed at which blood flows through the lungs.
Explain a high V/Q, give an example and a cause.
High V/Q is caused by inadequate perfusion (i.e. Shock)
5:1 ratio
V - 5 is good ventilation
Q - 1 poor perfusion
Explain a low V/Q, give an example and a cause.
A low V/Q is when there is not enough O2 available.
1:5
V - 1 - poor ventilation
Q - 5 - good perfusion
What is pulmonary vascular resistance?
The amount of resistance the R ventricle has to overcome to pump blood through the pulmonary vasculature by way of the pulmonary artery.
What can cause an increase in pulmonary vascular resistance?
An decrease in surface area (i.e. CF)
An increase in blood viscosity (as seen in cyanotic heart disease)
What physiological differences exist in the lungs/thorax/upper airway of an infant/young child that increase the likelihood of respiratory distress?
- Lung volume increases x4 in the first year.
- Kids have smaller alveoli, more likely to collapse.
- Infants have cylindrical chests - the AP diameter > the transverse diameter until 3 y.o.
- Elongated epiglottis that lies high in the pharynx and is more anterior
- Obligatory nose breathers until 6 months old.
- Infants/young children have greater chest compliance.
- Infants/young children have weaker intercostal muscles that cannot stabilize the chest wall against the diaphragm - leading to retractions
What type of blade is generally used to intubate an infant? Why?
Miller blade.
An infant has a high and anteriorly placed epiglottis that is floppy - the straight blade can move the epiglottis out of the way.
What type of blade is used to intubate older children and adults?
Mac Blade
Older children/adults have stiff epiglottis’ - curved blade appropriate.
What anatomical feature is the narrowest part of the airway?
Cricoid cartilage -
Acts as a natural cuff until 8 yrs old
Theoretically children under the age of 8 should not need a cuffed tube for intubation.
What anatomical features are included in the larynx?
What is the pedestrian name for the larynx?
The larynx includes: Epiglottis Supra glottis Vocal cords Glottis Sub-glottis
Commonly called the “voice box”.
What structures does the larynx connect?
The larynx connects: Pharynx Thyroid cartilage Cricoid cartilage Trachea
TLC
Total Lung Capacity
The volume o the lungs at max inspiration
TLC = FRC + VC + RV
VC
Vital Capacity
Max volume expired with max effort
FRC
Functional Residual Capacity
Volume remaining in the lungs after normal expiration
RV
Residual Volume
Volume remaining in the lungs after forced expiration.
What compensatory mechanisms does the body employ to change the pH of the blood?
Lungs
- increased rate and depth to increase tidal volume to blow off more CO2 makes the blood more alkalotic.
- Decreased rate and depth to decrease tidal volume to retain CO2 makes the blood more acidotic.
Kidneys
- change absorption of H+ ions and bicarbonate.
- decreased absorption of H+ ions leaves more H+ ions in the blood makes the blood more acidotic.
What function does PaCO2 provide information about?
Alveolar ventilation
What numerical level defines hypercarbia?
PaCO2 > 55 mmHg
What does the PaO2 provide information on?
Oxygenation status.
What numerical level defines hypoxia?
PaO2 <60 mmHg
State high/low for each: pH, PCO2, HCO3 for
Respiratory acidosis with metabolic compensation:
pH: L
PCO2: H
HCO3: H
State high/low for each: pH, PCO2, HCO3 for
Metabolic and respiratory acidosis
pH: L
PCO2: H
HCO3: L
State high/low for each: pH, PCO2, HCO3 for
Metabolic alkalosis with respiratory compensation
pH: H
PCO2: H
HCO3: H
State high/low for each: pH, PCO2, HCO3 for
Metabolic and Respiratory Alkalosis
pH: H
PCO2: L
HCO3: H
List the causes and symptoms of respiratory acidosis and high/low for pH, PCO2 and HCO3.
Due to inadequate ventilation - CO2 builds and increases H+ ions leading to acidosis
- Inadequate ventilator settings
Symptoms:
- Tachycardia
- Tachypnea
- Atrial and ventricular dysrhythmias
- Increased ICP
pH: low
PCO2: High, >45 mmHg
HCO3: Normal or high
List the causes and symptoms of respiratory alkalosis and high/low for pH, PCO2.
pH >7.45
PaCO2 <35 - lungs blow off too much CO2
Symptoms: Diaphoresis Dizziness ST changes - dysrhythmias Muscle spasm
Causes:
- seen in adults who hyperventilate
- uncommon in children unless ventilator setting require adjusting.
List the causes and symptoms of metabolic acidosis and high/low for pH and HCO3.
pH < 7.35
HCO3 < 22
Symptoms: Tachycardia Tachypnea Vision changes H/A N/V/D
Causes:
DKA
Renal issues - acute renal injury
List the causes and symptoms of metabolic alkalosis and high/low for pH and HCO3.
pH > 7.45
HCO3 > 26
Dysrhythmias
Tachycardia
Lethargy
Muscle weakness
Causes:
Prolonged emesis or NG suctioning
When suctioning a trach how big should the catheter be?
50% of the size of the trach tube.
When suctioning a trach what should the suction pressure be?
80-100
What events lead to cardiopulmonary arrest?
Hypoxia
Hypercarbia
Bradycardia
Respiratory arrest
DOPE
If a mechanically ventilated pt suddenly deteriorates use DOPE to determine the cause:
D- displacement
O- obstruction
P- pneumothorax
E- equipment failure
When is NPPV used?
Name 2 types.
Noninvasive positive pressure ventilation is used when a pt needs to keep his airway open AND can breathe independently
Types: CPAP, BiPAP
CPAP
Continuous positive airway pressure:
Administers same constant pressure during inspiration and expiration.
BiPAP
Biphasic Positive Airway Pressure:
Difference in Pressure
Can sense inspiratory effort.
Name 2 main types of invasive ventilation/ventilators.
Volume control - Tv is controlled, but allows passive expiration
Pressure Control - Pt determines Tv
Explain positive pressure ventilation:
Positive pressure ventilation forces air into the lungs by exceeding alveolar pressure.
Mode can be spontaneous or mandatory.
Explain controlled ventilation
Predetermined number of breaths per minute is set.
Requires sedation and paralyzation.
Explain AC ventilation
Assist-Control Ventilation
Rate is set, volume/min is set
with Volume Guarantee- if pt initiates low volume breath vent will finish the breath at the set volume.
This can lead to excessive ventilation (increased minute volume)
Which can lead to respiratory alkalosis, especially if the pt respiratory rate increases for non-respiratory reasons.
SIMV
Synchronized intermittent mandatory ventilation:
R is set, Tv- min set
Additional breaths initiated by the pt are permitted but not assisted by the ventilator.
By setting a high rate you provide total respiratory support
Explain spontaneous ventilation on a ventilator.
Allows pt to take breaths on own without any vent support.
Allows for monitoring of exhaled volumes and airway pressures.
Requires slight increased WOB over T piece (must overcome resistance created by vent circuit to initiate flow).
What is PEEP?
Positive end expiratory pressure.
Applied to keep alveoli from prematurely collapsing during exhalation.
It increases compliance and V/Q matching.
When is PEEP appropriate/necessary?
Tx hypoxia from lung injury
Prevent alveolar collapse in restrictive airway when the FRC is decreased.
What ventilator modes can PEEP be applied to?
All ventilator modes.
What are complications from applying PEEP?
Increasing mean and peak airway pressures can lead to barotrauma.
High pressure in the lungs = increased intrathoracic pressure = increased RA pressure, decreased venous return (and therefore decreased RA fill) = DECREASED CO
{If CO drops but O2 increases, fluid bolus may correct CO}
PEEP (and CPAP) can also: Increase ICP Decrease renal perfusion Increase hepatic congestion (increased intrathoracic pressure) Worsen intracardiac shunts
List normal values for PIP, based on age:
Newborns: 10-12 mmHg
Older infants/Children: 12-15 mmHg
Teens/Adults: <20 mmHg
What factors determine PIP?
- Lung compliance
- I time
- Airway resistance
- Tv
What is a normal tidal volume?
4-7 mL/kg
What is dead space ventilation?
It is the 1/3 of the Tv gas that occupies the airway lumen but does not participate in gas exchange.
Explain what HFJV is and how it works.
High frequency jet ventilation.
Rate, I- time, Pressure and Peep and volume are set
Rate is 100-600 breaths/min
Passive exhalation
Tv are small 1-3mL/kg
Higher mean airway pressure but lower peak airway pressure than conventional ventilator.
The jet (small tube) is placed as low as possible into the lungs, spiraling gas stream, high velocity
What are the advantages of HFJV?
Reduced chance of barotrauma (low Tv and pressures)
Forces CO2 against walls, penetrating dead space.
What is HFJV used for?
BPD
Chronic lung disease
Pulmonary interstitial emphysema
Which uses greater pressures, the JET or the Oscillator?
Oscillator
What are the advantages of using an oscillator?
Helps expand alveoli
Decreases pulmonary vascular resistance
Improves VQ matching
Decreases risk of barotrauma
What type of conditions are tx with the use of an oscillator?
RDS
{young infants with RDS may be placed directly on oscillator, skipping a conventional vent to avoid barotrauma}
Primary Pulmonary Hypertension (PPHT) r/t:
Meconium aspiration
Air leak syndrome
Pulmonary interstitial emphysema
Congenital Umbilical hernia
Describe the general function of HFOV.
Disperses gas throughout lungs at high frequency
Constantly infuses fresh gases and evacuates old ones
Active inspiratory and expiratory phases - completely controlling pt respiratory cycle
What is ECMO?
Extracorporeal Membrane Oxygenation
Provides prolonged cardiopulmonary bypass with membrane oxygenation by pumping blood outside of the body for oxygenation with a cardiopulmonary bypass machine
