Mechanical Ventilation Flashcards
What is an example of negative pressure ventilation?
Iron Lung
What are some examples of positive pressure ventilation?
Machine ventilator
CPAP
Bagger
Another person
Pressure created outside of the lung for inhalation
Why might mechanical ventilation be required?
- Control a patient’s respirations during surgery
- to oxygenate the blood when the patient’s mechanical ventilation efforts are inadequate
- rest the respiratory muscles
What are some indications for endotracheal intubation and mechanical ventilation?
- Continuous decrease in oxygenation (PaO2)
- Increase in arterial carbon dioxide levels (PaCo2)
- Persistent acidosis
- Conditions such as thoracic or abdominal surgery, drug overdose, neromuscular disorders, inhalation injury, COPD, multiple trauma, shock, multisystem failure, and coma may all lead to resp failure
What are clinical manifestations that indicate mechanical ventilation?
- apnea or bradypnea
- respiratory distress with confusion
- Increased work of breathing not relieved by other interventions
- Confusion with need for airway protection
- Circulatory shock
- Controlled hyperventilation (e.g., patient with a severe head injury)
What are three types of positive-pressure ventilators?
- Volume-cycled
- pressure-cycled
- high-frequency oscillatory support
What are key steps to respiratory assessment?
- History
- Inspection
- Auscultation
- Palpation
- SpO2 monitoring
- ABG (basic)
What is ventilation?
Movement of air in and out of airways
What are examples of invasive airways?
- Oral
- Nasal
- Tracheal
What are examples of non-invasive airways?
- OPA (oropharyngeal airway)
- NAP (nasopharyngeal airway)
What are the characteristics of a volume-cycled ventilator?
- Deliver a pre-set volume of air with each inspiration
- Exhalation occurs passively
- Volume of air is relatively constant, ensuring consistent, adequate breaths despite varying airway pressures
What is a disadvantage of a volume-cycled ventilator?
Patient may experience barotrauma because the pressure required to deliver the breaths may be excessive
What is barotrauma?
Trauma that causes damage to the alveolar capillary membrane and air to leak into the surrounding tissues.
How does a pressure-cycled ventilator work?
When a pressure-cycled ventilator cycles on, it delivers a flow of air (inspiration) until it reaches a pre-set pressure, and the cycles off, and expiration occurs passively.
What is a major limitation of pressure-cycled ventilators?
The volume of air or oxygen can vary as the patient’s airway resistance or compliance changes. As a result, the tidal volume delivered may beinconsistent, possible compromising ventilation.
How is acute respiratory failure (ARF) clinically defined?
PaCO2 greater than 50 mmHg
pH less than 7.30
and/or
PaO2 less than 60 mmHg
What is the most common indication for ventilator support?
Acute ventilatory failure. Inability of the lungs to maintain adequate alveolar ventilation. Diagnosed on the basis of the acid-base balance it creates: acute respiratory acidosis.
What is shunting?
Refers to the state in which pulmonary capillary perfusion is normal but alveolar ventilation is lacking. Pulmonery capillary blood can’t pick up oxygen from the nonfunctioning alveolar unit; if there are too many non-functioning units, there can be a decrease in SaO2, causing hypoxemia.
What are some common tests to assess pulmonary function?
vital capacity, negative inspiratory force, and respiration rate.
What respiratory rate significantly increases the work of breathing, leading to respiratory muscle fatigue?
35 breaths per minute