Lect 1. Mod 1. Oxygenation and Oxygen Therapy (NS2P2)

  1. *Principles of Gas Exchange 
    -affinity in hemoglobin.
    • Pulmonary gas exchange requires adequate ventilation and perfusion
    • -ventilation: getting aire into lung
    • -Perfusion: getting oxygen into tissues

    Oxygen and carbon dioxide exchange occurs via diffusion in lungs, across the alveolar -capillary membrane'

    Oxygen is both dissolved in the plasma and transported by Hgb in the blood; each hemoglobin molecule has 4 iron molecules and each atom can carry 1 02 molecule

    We can measure arterial blood oxygenation by the PaO2 (peripheral pressure of oxygen in arterial blood) and the SaO2 (oxygen saturation-pulse ox)

    • =>The affinity of Hgb for oxygen depends on the PaO2 (oxygen level that the hemoglobin is exposed to) that Hgb is exposed to
    • High in the lungs- Hgb binds readily
    • Low at the tissues- Hgb releases easily
  2. **Measurement of Oxygenation: Pulse Ox
  3. =>Pulse Oximetry: A noninvasive method to monitor the oxygen saturation of the blood
    • Does not replace ABGs
    • Normal level is 95-100%.
    • May be unreliable
  4. **Oxygen- Hemoglobin Dissociation Curve
    • The curve reveals more pressure of oxygen results in more saturation in blood. 
    • -we want pressure of O2 to be between 80-100 because it'll saturate most blood.
    • -Goal: don't allow the graph to shift. 

    • => Shift Left: More Oxygen in blood = Increased "Affinity". This is when you're hyperventillating, blowing too much CO2 causing respiratory alkalosis
    • -Oxygen in BLOOD but not TISSUES (HYPOXIA)
    • -Decreased temp: cold slows down transfer, so oxygen won't transfer effectively to tissues.
    • -Decreased 2,3, DPG
    • -Decreased CO2 (due to increased O2 taking space)
    • -Increased pH
    • -Respiratory Alkalosis

    • => Shift Right: Less Oxygen in Blood = "Decreased affinity". Results in hypoxemia.
    • -HYPOventillation, decreases pH (Respiratory acidosis).
    • -Increased temp (Fevers-tissues require more oxygen)
    • -Increased 2,3, DPG
    • -Increased CO2 (oxygen is now forced into tissues)
    • -Decreased pH
    • -Respiratory Alkalosis.
  5. **Measurement of Oxygenation: ABG's
    • Arterial Blood Gases (ABGs)
    • Invasive monitoring of PaO2 and SaO2

    • Normal level for PaO2 (partial pressure of oxygen) is 80-100 mmHg
    • Also measures acid-base balance-usually done by RT, puncture radial artery, painful procedure
  6. **Measurement of Oxygenation: Pulse Oximetry
    • A noninvasive method to monitor SaO2
    • Does not replace ABGs
    • Normal level is 95-100%; COPD can live in the 80's.May be unreliable: nailpolish, poor placement, so place it on the ears.-desaturation is a LATE sign of hypoxia.
  7. **Hypoxemia and Hypoxia
    • =>Hypoxemia
    • Condition in which oxygen content of the BLOOD is below normal
    • May not cause hypoxia if patient is able to compensate
    • -may not lead to hypoxia IF patient can compensate.
    • -can't test oxygen in tissues directly, you can only test the blood.

    • =>Hypoxia
    • Deficiency in oxygenation at the TISSUE level
    • Can be secondary to hypoxemia but may be due to impaired oxygen delivery or impaired oxygen utilization
    • -secondary to hypoxemia, may be due to impaired posturing?
    • -body compensates: increased HR, ventilation, Respiratory rate, shunt away blood from non-vital tissues, (more to kidneys and brain).
    • -Might be due to impaired delivery, like During decreased output, increased resistance (narrowing arteries) and decreased hemoglobin (anemia)
  8. **Clinical Manifestations of Poor Oxygenation
    -Early: CNS changes, tachypnea, dyspnea on exertion, HTN, tachycardia, diaphoresis, increased urinary output (body is trying to compensate-increased metabolism and HR-leads to urine output but if body can't keep up with this then it goes to the late signs)

    -Late: Increased CNS changes, respiratory distress, hypotension, cyanosis, clammy skin (by the time BP decreases, you're in trouble.)

    -Long-term: Clubbing of fingers (like in COPD), Barrel chest (from longterm hypoxia)
  9. **Age-Related Respiratory Changes
    =>Structural: Stiffening of chest wall, increased AP diameter (barrel chest), cartilage calcification, osteoporotic changes, decreased muscle strength

    =>Defense Mechanisms: Decline in immunity, less forceful cough, fewer cilia (in lungs), dry mucus (make more susceptible to pneumonia, etc).

    => Respiratory Control: More gradual response to changes in PaO2 or PaCO2 (body takes a little longer to compensate)
  10. **Mechanisms to Compensate for Hypoxia
    =>O2 moves from tissue that have low O2 need to tissues that have higher O2 requirement (vital organs): Skin to brain, and Muscle to myocardium

    =>Increased production of RBC’s: To increase oxygen binding capacity (this will take longer)
  11. **Oxygen Therapy
    =>The administration of oxygen at concentrations greater than room air (FiO2> 21%)

    =>Goal of treating or preventing the s/s of hypoxia

    • =>Used to
    • Reduce the work of breathing
    • Reduce workload of heart
    • Maintain PaO2> 60 or SaO2>90
  12. **Nasal CannulaLow flow device: 1-6 L/min, O2 concentration 25-45% (not guaranteed, it's called variable because you are getting room air still, it's just supplemental oxygen)- greater than 4L O2 should be humidified.-1L is 24% and 6L is 44%=> AdvantagesCan eat, talk, cough while in placeinexpensive=>DisadvantagesO2 concentration variable, may not be enough.Higher flow rates dry out nasal mucosa-short term after surgery and long term for COPD
    • Low flow device: 1-6 L/min, O2 concentration 25-45% (not guaranteed, it's called variable because you are getting room air still, it's just supplemental oxygen)
    • - greater than 4L O2 should be humidified.
    • -1L is 24% and 6L is 44%

    • => Advantages
    • Can eat, talk, cough while in placeinexpensive

    • =>Disadvantages
    • O2 concentration variable, may not be enough.
    • Higher flow rates dry out nasal mucosa-short term after surgery and long term for COPD
  13. **Simple Face Mask
    • Low flow device: 6-12 L/min, Concentration 35-50% of FiO2 can be acheived
    • -less than 5L, then risk of rebreathing your CO2 because not enough flow.
    • -Longer use typically not tolerated due to tight seal around nose/mouth
    • -mask provided adequate humdicaation of inspired air.

    • =>Advantages
    • Easy to useProvides humidification (water vapor)

    • =>Disadvantages
    • Uncomfortable for patient Has to be removed to eat; if they're destating, it's dangerous. Might use NC temp while eating.
    • -if pt on floor is "crumping" in ICU (going downhill) the first thing you should do is get a mask from central supply cart and turn O2 all the way up (First priority)
  14. **Reservoir Masks
    • =>Partial Rebreather: 6-10 L/min and 60-90% O2 (like simple mask with bag attached to it-fill bag with O2 First, and more controlled environment, they're not breathing any rooom air, just breathing what's in that bag.)
    • Open vents in reservoir bag allows patient to rebreathe 1/3 exhaled air (little room air)
    • -can control o2 amount better.Should not totally deflate

    • =>Non Rebreather: Delivers 95%-100% O2 at 10-15 L/min
    • Only oxygen in bag is inspired
    • Should not totally deflate: O2 flow must be sufficient to keep bag from collapsing during inspiration to avoid CO2 buildup
    • -use short term, long term leads to Oxygen toxiciity (really high level of O2)
    • -make sure valves are open during expiration and closed during inhalation to prevent drastic decreasein FIO2.
  15. **High Flow Systems
    • => Venturi Mask: Device is attached to mask that delivers rates of precise O2 concentrations
    • -looks like regular mask but with different colors, each color gives different amount of oxygen
    • -easier to control how much oxygen you want.

    • => Tracheostomy Collar, T piece
    • Can be used w/ venturi devices; Allows humidification
    • T-piece is the the part they put on Endotracheal tube. Allows for inline suction, so you so don't have to be sterile while sterile suctioning
    • -traches: O2 MUST BE HUMIDIFIED, because you're bypassing that upperairway which normally functions to humidify the O2 in air.

    =>Mechanical Ventilation: most controlled and most invasive.
  16. **Complications of O2 Therapy
    • -Reduction of respiratory drive in patients with chronic low oxygen tension,
    • -with COPD, high O2 levels can reduce their respiratory drive to breath. (Normally CO2 accumulation is the major stiumlant of the respiratory center, but COPD develop a tolerance for high CO2 levels--the respiratory center loses it's sensitivery of elevated CO2 levels so their drive to breathe is "hypoxemia". Therefore high O2 levels reduce their drive to breathe)
    • -Drying of mucous membranes (with no humidification)
    • -Fire (oxygen feeds fires)

    • =>Oxygen toxicity: prolonged exposure to high concentrations can result in free radical formation in body and inflammatory response-common in pt who have been ventillated for a while.
    • Therapy >50% (FiO2) and 24 hours potentially toxic
    • Can lead to tracheobronchitis and ARDs (Acute Resp Disease)

    • =>Prevention
    • Use lowest concentrations of O2 possibleUse
    • ABGs to guide therapy
    • PEEP (Partial expiratory End Pressure-extra puff of air after breath that keeps alveoli open) or CPAP (continuous Positive Airway Pressure--sleep apnea) prevents or reverses atelectasis and allows lower oxygen percentages to be used.
  17. **Oxygen Toxicity:  Symptoms
    • Substernal discomfort
    • Paresthesias
    • Dyspnea
    • Restlessness
    • Fatigue
    • Malaise
    • Progressive respiratory difficulty
    • Refractory hypoxemia
    • Alveolar atelectasis
    • Alveolar infiltrates on x-ray

    => Reading:

    -High concentrations result in severe inflammatory response b/c oxygen radicatls damage to alveolar capilarry membranes resulting in severe pulmonary edema, shunting of blood and hypxemia. --> ARD (acute resp distress)-All levels above 50% and O2 used longer than 24 hours should be considered toxic.

    -Absorption Atelectasis: High O2 concentration causes nitrogen to wash out of the alveoli and replaced with O2, If airway obstruction occurs, the Oxygen is absorbed into the bloodstream and the alveoli will collapse.

    -Infection: Heated nebulizers provided highest risk-supports bacterial growth. Use a closed system such as "Ballard closed suctioning system"

    -Chronix Oxygen therapy at home (LTOT): more than 15 hrs/day: impurove mental acuity, exercise tolerance, decreasted hematocrit and reduced pulmonary hypertension.

    -Short term home O2 Therapy: 1-30 days.
  18. **Ventilation/Perfusion (V/Q Ratio)
    -V/Q scan to see if there's a mismatch.

    • => Ventilation
    • Movement of air in and out of the lungs
    • Air must reach the alveoli to be available for gas exchange.

    • =>Perfusion:
    • Filling of the pulmonary capillaries with blood Adequate gas exchange depends upon an adequate V/Q ratio/match
    • Shunting occurs when there is an imbalance of ventilation and perfusion resulting in HYPOXIA
  19. **Measurement of Volume=>Incentive Spirometer
    • Measures volumes of air inhaled
    • Used to assess lung capacities
    • Promote pulmonary toilet activities post-op
    • When assessing tidal volume, measure several breaths and record average

    • **Incentive Spirometer
    • Types: volume and flow-measured in ML's. Normally we can get 2-3K mL's
    • -goes with TCDBing
    • Device ensures that a volume of air is inhaled and the patient takes moderately slow, deep breaths. Used to prevent or treat atelectasis
    • -Done Q6M, 10x in an hour. Document the results, and if they're doing it independently or if you have to remind them.

    => Nursing care: Positioning of patientEducation/ObservationHow often done?, Set realistic goalsRecord the results
  20. **Intermittent Positive-Pressure Breathing (IPPB)
    • -bedside temp mechnaical ventillator for pts that need that extra therapy.
    • Indicated for patients who need to increase lung expansion
    • increased breathing pressures are delivered via ventillator but don't have to be incubated.
    • -treates atelectasis, clear secretions, delivers nebulized meds (dont by RT)

    • =>Monitor for side effects
    • Pneumothorax
    • Increased intracranial pressure (neuro patients-don't try it)
    • Hemoptysis
    • Gastric distention
    • Psychological dependency
    • Hyperventilation
    • Excessive oxygen administration
    • Cardiovascular problems
  21. **Mini-Nebulizer Therapy
    • =>A hand-held medication delivery device-water vapor coming out.
    • Disperses a moisturizing or pharmacologic agent or such as a bronchodilator into the lungsMust make a visible mist

    • =>Nursing care
    • Education of use - Patient is to breathe with slow, deep breaths through mouth and hold a few seconds at the end of inspiration - Coughing exercises may be encouraged to mobilize secretions after a treatment- Rinse mouth before and AFTER use (to avoid thrush/yeast infections)
    • -corticosteroids
    • Equipment care
    • Assess patient before and after treatment and evaluate patient response
  22. =>Additional Diagnostic Tests
    • Chest x-ray (portable x-rays-one view in bed
    • Sputum tests: Serial (culture, bacteria
    • Computed tomography (CT)
    • Magnetic resonance imaging (MRI)
    • Fluoroscopic studies and angiography

    • Radioisotope procedures (lung scans): V/Q Scan (inhale radioisotope and scan to see where that isotope has gone),
    • PET scan (whole body scan),
    • Gallium Scan (homeologist-put down little camera into lungs, tissue biopsies, to diagnose)
    • Bronchoscopy
    • Thoracoscopy
    • Thoracentesis (punctures lung to draw out excess fluids)
    • Biopsies
  23. **Pre-Diagnostic Lung Procedure Nursing Process
    • => Assessment
    • Informed consent
    • NPO status
    • Procedural checklist: Labs, IV (always flush IV before sending someone to a test)

    • =>Diagnosis
    • Knowledge Deficit
    • Anxiety
    • Risk for ineffective cardiopulmonary tissue perfusion
    • Risk for impaired gas exchange/airway obstruction

    • =>Plan
    • Maintain airway
    • Maintain homeostasis
    • Verbalize knowledge of procedure
    • Minimize anxiety
  24. **Post-Diagnostic Lung Procedure Nursing Process
    • =>Interventions
    • Monitor V/S (including pain)
    • Administer oxygen
    • Auscultate lungs
    • Position for comfort/oxygenation
    • Check gag reflex
    • Keep hydrated to minimize thick secretions
    • Monitor surgical site

    • =>Evaluation
    • Patent airway
    • Clear lung sounds
    • Adequate oxygenation
    • Stable V/SPain controlledPositive gag reflexSurgical site intact
  25. **Post-Diagnostic Lung Procedure Nursing Process
    • =>Assessment
    • Airway
    • Comfort
    • S/S bleeding
    • Gag reflex

    • =>Diagnosis
    • Alteration in comfort/pain
    • Risk for aspiration
    • Risk for ineffective cardiopulmonary tissue perfusion
    • Risk for impaired gas exchange/airway obstruction

    • =>Plan
    • Maintain airway
    • Maintain oxygenation/homeostasis
    • Keep comfortable
    • Demonstrate safe swallowing
    • No S/S aspiration
  26. **Patient ScenarioYou are caring for a patient who is 3 hours post thoracentesis. Upon assessment of the procedure site, you note the dressing is saturated with serosanguineous fluid. What is your first action?

    Notify the MD.

    Put a new sterile dressing on.

    Reinforce the dressing.

    Complete a pulmonary nursing assessment.
    Complete a pulmonary nursing assessment. (check resp status first then you can call the doc or we.)
  27. **Patient Teaching: Home Oxygen
    Safety considerationsFlow rate and flow adjustmentMaintenance of equipmentIdentification of malfunction HumidificationOrdering of supplies and oxygenSigns and symptoms to reportDiet and activity, travelElectrical outlets
  28. O2 Goals:
    SaO2 greater than 90% during rest, sleep, and exertion and PaO2 greater than 60 mmHg

    -FIO2: Fraction of Inspired Oxygen

    => humidification: Either through bubble-trhough humidifier or a nebulizer (uses water mist-heating the water increases gase's ability to hold moisture)
Card Set
Lect 1. Mod 1. Oxygenation and Oxygen Therapy (NS2P2)
Oxygenation and Oxygen Therapy: