Respiratory Disorders Flashcards
What is ventilation?
Movement of air to AND from alveoli and atmosphere by airways due to result of changing thorax size
Breathing air in ↓’s intrapulmonary pressure
Breathing air out ↑’s intrapulmonary pressure
Describe the changes in PCO2 and pH associated with hypoventilation
Hypoventilation= less airflow in / out of the lungs –> (↑ pCO2) and ↑pH (respiratory acidosis)
Describe the changes in PCO2 and pH associated with hyperventilation
Increased airflow in / out of the lungs –> ( ↓ pCO2) and ↓ pH (Respiratory alkalosis)
Where is the respiratory center of the brian located?
Medulla
A spinal cord injury at which locations will cause a paralyzed diaphragm?
- “C-3,4,5”= keeps the diaphragm alive”,
- Spinal Cord Injury at C3 and above will cause paralysis of the diaphragm –>
- Mechanical Ventilation required
- Diaphragm = major insp. Muscle
What is the normal negative inspiratory force in a patient?
¢Normal Negative Insp Force (NIF) is > -100 cm H2O
At what negative inspiratory force level is intubation required?
¢A NIF of
Describe the changes in inspiration and expiration associated with a flail chest
- Flail Segment unable to contribute to lung expansion.
- On Inspiration: Chest supposed to expand, but flail section “sinks in”
- On Expiration: Flail section “bulges outward”, poor exhalation
What is compliance?
- Ability of lungs to expand
- Influenced by changes in pressure and volume
Describe what happens with low compliance in the lungs
- Low compliance: “stiff lungs” = lungs with decreased ability to fill with air
- Difficult to expand alveoli, lungs
- Takes more pressure to increase lung volume (means more work for the pt.) –>
- Results in: Increased work of Breathing, Dyspnea, Tachypnea
What are causes of a low compliance in the lungs?
-
Obesity (ex: Pickwikian Syndrome)
- Increased intrapulmonary pressure –> increased effort to breathe
-
Decreased surfactant production (ex: ARDS)
- Leads to alveolar collapse –> makes it harder to inflate alveoli with are –> ↓ compliance on the lungs
-
Restrictive lung disease:
- Pneumonia (lungs can’t fill up with air if there’s fluid in the alveoli)
- Pneumothorax (lungs can’t fill up with air since it’s collapsed, and there is an increase in positive pressure)
- Pulmonary edema (too much fluid in da lungs bruh)
Describe the two types of respiration
- External (External environment to Capillary-Alveolar interface)
- Internal (Capillary to Tissue, Cells)
What 4 factors affect the diffusion of air across the alveoli?
-
Partial pressures of gases (pO2 and pCO2) and gradient
- Ventilation
-
Surface area (of alveoli)
- Atelectasis, Tumors
-
Thickness (of the alveoli)
- Inflammation, Alveolar edema (ARDS), Fibrosis (Sarcoidosis)
- Length of exposure
Describe the changes that occur with a left shift in the oxyhemoglobin curve and what causes it.
Changes:
- A Left Shift increases O2 attraction to Hgb
- Conditions make Oxygen easier for Hemoglobin to pick up; but O2 will tend to stay on Hgb and does not release easily to tissues
- Tissue hypoxia will occur
Causes:
- High pH
- Low temperature
- Low PaCO2
Describe the changes that occur with a right shift in the oxyhemoglobin curve and what causes it.
Changes:
- A Right shift decreases O2 attraction to Hgb
- Conditions cause O2 to have less attraction to Hgb; but O2 is readily released to tissues (there is less binding, so not as much O2 available as in normal states)
- Tissue hypoxia will occur
Causes:
- Low pH
- High temperature
- High PaCo2
What is a Ventilation-perfusion match?
- It is the relationship between how well an alveoli is ventilated and how well an alveolar capillary is perfused.
- Ideally, a 1:1 V/Q ratio between alveolar airflow & blood flow would exist
- “V” ventilation- air that reaches alveoli
- “Q” perfusion- blood that reaches alveoli
- “V” and “Q” are main determinants of blood O2 concentration
Describe High V/Q ratios and what causes them
High V/Q ratios (poor perfusion) result from follow-ing conditions:
- Decreased Cardiac Output
- Pulmonary emboli
- Pneumothorax
- Destruction of pulmonary capillaries
Describe low V/Q ratios and what causes them
Low V/Q ratios (poor ventilation) result from the following conditions:
- Hypoventilation
- Obstructive lung disease
- Restrictive lung disease
- Effects of V/Q:
- Hypoxemia
- Acidosis
- Hypercapnia
Describe what a pulmonary shunt is
- Major cause of hypoxemia in HA pts.
- Anatomic shunt - blood doesn’t come in contact with the alveoli because of trauma to blood vessels.
- Capillary shunt - normal blood flow across dysfunctional alveoli r/t atelectasis, pulmonary edema
- Absolute shunt - combo of both anatomic and capillary shunt
How and when would you estimate an intrapulmonary shunt?
- Use only if PaCO2 is stable
- Calculated by the formula = PaO2 / FiO2
- Normal values= 350-450
- Minimal accepted value= 286
What are normal HCO3 levels?
22-26
What do changes in base excess indicate?
> +2 = metabolic alkalosis
How would you manage a patient in metabolic acidosis?
- Tx Cause: DKA, Renal Failure, Cardiac arrest, Shock, Diarrhea
- Sodium Bicarbonate if pH is
- If K+ level is
- DKA: Insulin and fluids
- Diarrhea: anti-diarrheals
- Renal failure: Hemodialysis, CRRT
How would you manage a patient in respiratory acidosis?
- Tx Cause: Hypoventilation states, airway obstruction, neuromuscular disease
- Support ventilation. May need to intubate and put on ventilator, Increase tidal volume and / or RR on vent
- Bronchodilators,, Chest PT, Bronchoscopy with lavage
- Encourage pursed lip breathing
How would you manage a patient in metabolic alkalosis?
- Tx Cause: Severe vomiting,
- nasogastric suction, diuretics, corticosteroids, overventilation intestinal obstruction
- Saline infusion may correct chloride deficit d/t gastric losses
- KCL for pts with low K+ levels
How would you manage a patient in respiratory alkalosis?
- Tx Cause: Hyperventilation states, Anxiety, pain, fever,
- O2 therapy if hypoxemia is problem
- Provide reassurance, remain w/ pt
- Encourage pt to breathe slowly
- Sedation prn
- Possibly rebreathe air into a paper bag
- ON vent: decrease RR or tidal volume and add deadspace prn
What are the respiratory signs of hypoxemia?
- Dyspnea
- Prolonged expiration (I:E= 1:3 or 1:4)
- Intercostal retraction and other accessory muscles
-
Late signs:
- Paradoxical chest/abd movement
- Cyanosis
What are non-specific signs of hypoxemia?
- Agitation, Disorientation, Restlessness, Combativeness
- Tachycardia, HTN
- Skin cool, clammy
- Fatigue
- Unable to speak in complete sentences w/out pausing to breathe
-
Late signs:
- Dysrhythmias
- Hypotension
What are the respiratory signs of hypercapnea?
- Dyspnea
- Decreased RR or increased RR with shallow volume
- Decreased tidal volume
- Decreased minute volume
- Pursed lip breathing
- Tripod position
What are the non-specific signs of hypercapnea?
- Morning Headache, Disorientation, Progressive somnolence
- Dysrhythmias, HTN, Tachycardia, Bounding pulses
- Muscle weakness, Decreased DTRs
-
Late signs:
- Coma
- Tremor, Seizures
Describe type 1 respiratory failure
- Imbalance of O2 supply and demand
- Type I: Hypoxemia with failure of oxygenation
- PaO2
- Recall O2 has a decreased affinity to Hgb at this levelà any further decreases will create rapid decrease in SaO2!
- Examples: COPD, Pneumonia, ARDS, Restrictive Lung Disease
Describe type2 respiratory failure
- Hypoxemia and Hypercapnea
- PaO2
- PaCO2 > 50 mm Hg with a pH
- Examples: COPD, Neuromuscular Disorders, Respiratory muscle fatigue
What are Complications of Respiratory Failure?
- Hypercapnia and acidosis impair cellular function
- Vasodilatory effects can increase intracranial pressure and decrease cardiac output and vascular resistance
- You get vasodilation with an increase in CO2
- Considered more serious than oxygenation failure
Describe the Pathogenesis of Respiratory Failure
- Initiated by disease process interferes directly or indirectly with normal lung function
- As pulmonary function deteriorates, patient develops V/Q ratio abnormalities and decreasing PaO2
- Body compensates for increase in O2 demands by increasing rate and depth of respirations
- PaO2 increases and PaCO2 decreases
- More energy is required: metabolic rate increases
- More oxygen is required by tissues; more CO2 is produced
- Effect is an increase in arterial CO2 and decease in arterial O2
What is Non-Invasive Ventilation?
- Provides ventilatory support and avoids invasive artificial airway (ETT or trach)
- Allows for possible oral intake
- Uses oral or oronasal mask to deliver + Pressure
What are the indications for non-invasive ventilation?
Indications:
- Neuromuscular disease
- Home settings for chronic Respiratory Failure (COPD, CHF)
- Alternative to intubation in ED/ICU areas (Post-op, immunocompromised, to avoid reintu-bation, irreversible disease and pt does not want intubation)
- Sleep apnea
What are the different types of non-invasive ventilation?
Bilevel: also called “Bipap”
- Requires a ventilator
- Designed to prevent airleaks
- Inspiratory and Expiratory airway pressures
- Maintains minimum PEEP of 4 mmHg (EAP)
CPAP (continuous positive airway pressure)
- Provides continuous level of + airway pressure throughout breathing cycle
- Requires a device for flow delivery
- Useful for sleep apnea in home setting
NOTE: Positive pressure can lead to a decrease in cardiac output –> increased pressure on the heart –> makes it harder for the heart to push blood
