EXAM 3 Flashcards
Gas exchange relies
adequate perfusion of alveoli
ventilation vs perfusion
Ventilation = air coming in
Perfusion = blood flow to the capillaries
“alveolar dead space”
shunt unit
silent unit
a. “alveolar dead space” = alveolar not perfused -> no gas exchange occurring
Examples: PE and pulmonary infarct
b. “shunt unit” = alveoli not ventilated but perfusion intact -> perfusion > ventilation
Examples: pneumonia and atelectasis
c. “silent unit” = perfusion AND ventilation impaired
Examples: ARDS and pneumothorax
how is O2 transported
Oxygen transported in 2 ways:
1. 97% bound to Hgb (aka O2 saturation)
2. 3% dissolved in serum
what does a shift in the oxyhgb curve mean
that affinity of Hgb to O2 is changed
shift to the left
3 meanings and the factors
Hgb HOLDS onto O2
Increased O2 saturation
Impaired O2 delivery to tissues
Factors that shift the curve to the Left:
Low temperature (hypothermia)
ALkalosis (a rise in pH)
Low CO2
Low 2,3 diphosphoglycerate (in septic shock, hypophosphatemia, and blood transfusions)
shift to the right
3 meanings and the factors
Hgb has LESS affinity for O2
Decrease in O2 saturation
Brief temp increase in O2 delivery to tissue
HgB RELEASES O2 MORE READILY
Factors that shift the curve to the Right =
Rise in body temperature (fever)
Reduced pH (acidosis)
Rise in CO2 (hypercapnia)
Rise in 2,3 diphosphoglycerate
ph
measures hydrogen concentration in blood. Normal 7.35-7.45
SaO2
percent of hemoglobin saturated by O2. Normal 93-97%
PaO2
pressure of O2 in the blood. Normal 80-100 mmHg
PaCO2
tension of dissolved CO2 gas in arterial blood. Regulated by the lungs (respiratory process). Thought of as acid in interpreting ABGs. Normal 35-45 mmHg
HCO3
bicarbonate, main base in serum, helps regulate pH because it can accept hydrogen. Regulated by kidneys (metabolic process). Normal 22-26 mEq/ml
what is ARDS
SUDDEN, ACUTE, PROGRESSIVE form of acute respiratory failure = alveolar damage = HYPOXIA
3 steps in ARDS
Injury to lungs -> inflammatory response -> alveolar capillary membrane damage
1 cause of ARDS
1 : Sepsis leading cause bc its in inflammatory process
5 things happening in stage 1 ARDS and name of stage
- Capillary membranes leak
- Protein-rich fluid fills alveoli
- Gas exchange is disrupted
- Type 1 alveolar cells are destroyed(type 1s are responsible for gas xchange)
- Hyaline membranes are formed
6 s/s of stage 1 ARDS
Normal chest x-ray, or with dependent infiltrates
Tachypnea and dyspnea
Use of accessory muscles
Lung sounds may be clear
PAWP may be < 18 mm Hg
Change in level of consciousness
7 things happening in stage 2 ARDS and name of stage
- Type 2 alveolar cells are damaged(type 2s produce surfactant)
- Surfactant production declines
- Peak inspiratory pressure increases
- Compliance declines(think lungs ability to open and relax easily and smoothly)
- Decreased FRC (functional reserve capacity – ability to take an extra deep breath when needed)
- Further loss of alveolar function
- Ventilation/perfusion mismatch
7 s/s of stage 2 ARDS
fibroproliferative
Chest x-ray with bilateral infiltrates and elevated diaphragm
Refractory hypoxemia and hypercarbia despite hyperventilation
Dramatically increased WOB
Crackles on auscultation(crackles means fluid in alveoli – diuretics wont always work which usually does in other conditions )
Rhonci on auscultation means fluid outside of alveoli which coughing and deep breathing can help – or if mechanically vent. – need to be suctioned
PAWP, RA (CVP) increase
Right-sided heart failure develops - peripheral edema
Agitation
4 things happening in stage 3 ARDS and name
Development of fibrotic tissue in the ACM resulting in alveolar disfigurement
- Decreased lung compliance
- Worsening pulmonary hypertension
- Increased dead space ventilation
8 s/s of stage 3 ARDS
Leukocytosis and fever
Elevated WBC
Worsening infiltrates on chest x-ray
Worsening hypoxemia and hypercarbia
Decreased tissue perfusion
Increasing HR with decreasing BP
Lactic acidosis
End-organ dysfunction
goal of mechanical ventilation
The goal is to use the least amount of O2 needed (ideally < 60%) to keep SaO2 88-95%, and P/F ratio>200
are abx used for mechanical vent
only if infection
10 treatments of ARDS
mechanical vent
prone position, up in chair
ionotrpic meds for hemodynamic monitoring
mild fluid restriction, NG tube, PPIs
relieve bronchospasm albuterol
reduce air inflammtion salumetrol IV steroid
reduce pulmonary congestion
reduce anxiety
PEEP
check Hgb
4 reasons mechanical vent is used
IMV/ACV for respiratory rate
FIO2 to meet needs while aim is < 60%
restricting tidal volume to 4-8 mL/kg
pressure ventilation/PEEP to enhance gas exchange
ACV
patient receives a set tidal volume and breaths if patient’s own effort falls below set rate
SIMV
patient receives a set number of breaths with a set tidal volume, but with any additional breaths the patient’s effort determines tidal volume and allows use of respiratory muscles.
PEEP
at the end of expiration, it will deliver pressure to keep lungs open for longer to facilitate gas xchange instead of always adding O2
rapid sequence of intubation meds
- anesthetizing agents with a short half-life (diprivan (Propofol), midazolam (Versed), or etomidate
- paralytics such as succinylcholine, rocuronium
- long-term anesthetics and analgesics to reduce anxiety and promote comfort of the patient while intubated
diprivan - class, use, monitoring
- very short-acting anesthetic
- no analgesic properties
- less amnesia properties than benzodiazepines
- continuous infusion, titrated slowly
- Monitor for hypotension and lipid levels (after 2 days of infusion)
- High or excessive doses may result in Propofol infusion syndrome, hypotension, and zinc deficiencies.
10 nursing actions for intubation and ventilation
- Explain procedure
- Monitor oxygenation and cardiovascular status - alert hcp if o2 <90
- Administer medications
- Auscultate lungs to check for air movement after tube placement
- Utilize CO2 detector to verify placement
- Secure tube
- Note placement mark on the tube for future monitoring
- Monitor for patient awakening as the chocking sensation associated with the tube will create anxiety
- Chest x-ray following intubation is required to verify correct placement
- We want end of tube 0.5 cm above corina (C in pic) to ensure getting air to both side
how to prevent barotrauma in mechanical vent 2
- Use of lower tidal volumes (remember this is amt of air coming in from ventilator) (4-8 mL/kg of body weight) and permissive hypercapnia – prevents barotrauma and volutrauma
- Use of inverse ratio ventilation (IVR) – promotes slower delivery of tidal volume and helps prevent barotrauma
1 prevention of VAP
hand hygiene
9 ways to prevent VAP
- Hand hygiene #1
- Elevation of the head of the bed > 30 degrees to prevent aspiration
- Daily sedation vacations and assessment of readiness to extubate
- Peptic ulcer disease prophylaxis – histamine blocker( -tidines) or PPI (omeprazole)
- Deep vein thrombosis prophylaxis
- Oral care with chlorhexidine
- Suctioning using in-line system to prevent infection – remember suctioning used when you hear rhonci or if you see secretions in the tubing coming up
- Continuous subglottic suctioning
- No routine change of ventilator circuit
5 safety protocol for mechanical ventilation
- Suctioning to clear secretions as indicated, assessing need every 2-4 hours
- Response to ventilator alarms
- Appropriate use of restraints
- Facilitating communication – VS, body language, white boards, hand gestures
- Providing education
8 readiness to wean and extubate
- Adequate muscle strength and endurance- breathe long enough and strong enough on
- their own, can they cough up secretions? How much secretions?
- Clear lungs
- Stable cardiac/hemodynamic status
- Adequate nutritional status – adequate protein and calories
- Adequate hemoglobin
- Stable neurological status
- Spontaneous weaning trial – patient is placed on a T-piece, removed from the ventilator and connected to a humidified oxygen source and indicators are monitored
2 types of pneumothorax
- Closed – rupture of blebs on the visceral pleural space
- Tension – rapid accumulation of air in the pleural space resulting in extremely high intrapleural pressure with resulting tension on the heart and great vessels. A tension pneumothorax is an emergency situation.
small vs large s/s pneumot
- Small – tachycardia, dyspnea
- Large – respiratory distress, shallow, rapid respirations, dyspnea, air hunger, O2 desaturation, no breath sounds over affected area, presence of air or fluid on chest x-ray
treatment for pneumothorax
Chest tube insertion – removes air/fluid from pleural space and restores normal intrapleural pressure (negative) so lung can re-expand. Tube is inserted and connected to a drainage system
3 compartments of drainage system in chest tube
- First compartment – collection chamber
- Second compartment – H2O seal chamber
- Third compartment – suction control chamber
5 nursing actions for chest tubes
5 things to assess for sedation
a. level of consciousness, using Glasgow Coma Scale or Reaction Level Scale
b. For agitation and restlessness, using the Ramsey Sedation or Riker Sedation/Agitation Scale (RASS)
c. For anxiety
d. For sleep
e. For patient-ventilator synchrony (an indicator of comfort level)!!!!
3 classes of sedation meds with examples
a. Ativan (Lorazepam) – benzodiazepine***
b. Diprivan (Propofol) – short-acting general anesthetic***
c. Dexmedetomidine (Precedex) – an a2 agonist
ALL COMBINED WITH ANALGESIC
lorazepam - class, use, onset, SE
- benzodiazepine with anti-anxiety, sedative, and anti-convulsant effects.
- Slower onset (15-30 minutes), but longer duration (8 hours) than midazolam.
- Side effects include reversible renal tubular necrosis, lactic acidosis, hyperosmolar states, and delirium.
- Physical and psychological dependence can develop.
- Is not a first-line choice due to the risk for delirium.
dexmedatomidine - class, use, SE and tx of SE
- for short-term sedation, having anxiolytic, anesthetic, hypnotic
amd analgesic properties - Recommended for use of less than 24 hours.
- The most common side effect is hypotension requiring fluid replacement and slower administration
- Symptomatic bradycardia and heart block may develop, but usually resolve spontaneously.
how and when to assess for delirium
Assessment using the Confusion Assessment Method of the Intensive Care Unit (CAM-ICU) should be done at least once/shift.
6 nonpharm interventions for delirium and what is priority
A – analgesia: assess, prevent, manage pain / assess readiness to extubate
B – both SATs and SBTs: stop drugs, stop ventilator
C – choice of analgesia and sedation, cognitive stimulation (music), catheter removal
D – delirium: assess, prevent, manage
E – early mobility** and exercise, ROM exercise, low stimulation environment
F – family engagement and empowerment, facilitate sleep
