Mechanical Ventilation - EXAM 3 Flashcards
Mechanical Ventilation
The process by which room air or oxygen enriched air is moved into and out of the lungs mechanically. Not curative; a means of supporting patients until they recover or a decision is made to withdraw
Spontaneous Breathing
The lungs pull in air. The diaphragm contracts on inhalation, moving toward the abdomen, and the chest wall expands. The space inside the thorax enlarges and creates a vacuum that draws air into the lungs. This negative pressure aids in venous return to the heart.
Mechanical Ventilation Process
Air is pushed in. Mechanical ventilation pushes a warm, humidified mixture of oxygen and air into the lungs and creates a positive pressure in the thorax during inhalation. Lung tissue can suffer damage and venous return to the heart is reduced
Indications for use of mechanical ventilation
- Patients are unable to adequately ventilate (move air in and out of the lungs) which causes hypoxemia and respiratory acidosis
- Respiratory rates over 30 breaths per minute (60 in infants and young children) may lead to respiratory muscle fatigue and respiratory failure
- PaO2 of less than 40 and an oxygen saturation of less than 75% are inadequate to meet tissue needs. Hypoxia and cardiac dysrhythmias can be expected
- Dyspnea at rest, use of accessory muscles, intercostal retractions during inspiration, pausing for breaths between sentences or words, hypotension, cyanosis (in the presence of an adequate hemoglobin level), cool clammy skin, combativeness or coma
Negative Pressure Ventilation
Involves the use of chambers that encase the chest or body and surround it with intermittent negative pressure. This causes the chest to be pulled outward for inspiration, reducing intrathoracic pressure. Expiration is passive. This type of ventilation is similar to normal ventilation.
Positve Pressure Ventilation
Method in which the ventilator pushes the air into the lungs under positive pressure. Intrathoracic pressure is raised during lung inflation. Expiration occurs passively. Two categories:
- Volume ventilation
- Pressure Ventilation
Volume Ventilation (Positive PRessure Ventilation)
Delivers a predetermined tidal volume with each inspiration. The tidal volume is consistent but airway pressure will vary.
Pressure Ventilation (Positive Pressure Ventilation)
Delivers a predetermined peak inspiratory pressure while the tidal volume varies, changing in response to intrathoracic pressure.
Ventilator Modes
The variable methods by which the patient and ventilator interact to deliver effective ventilation. The chosen mode is based on how much WOB the patient can or should perform. The ventilator mode is determined by provider or respiratory therapist, based on the patient’s
- Ventilatory status
- Respiratory drive
- ABGs
Positive End Expiratory Pressue (PEEP)
A pressure applied to the patient’s airway at the end of expiration only. It can be used with any of the volume modes. The use of PEEP helps to keep alveoli from collapsing during exhalation. Lack of surfactant of the presence of edema in the interstitial spaces can also cause alveoli to collapse. PEEP provides a counter pressure. It is similar to the pressure that the glottis provides in patients who exhale with an expiratory grunt.
It is approxiately 5cm H2O (physiological PEEP). In intubated patients, the glottis is bypassed or splinted open. The mechanisms by which PEEP increases oxygenation included increased aeration of patent alveoli, aeration of previously collpased alveoli, and prevention of alveolar collapse throughout the respiratory cycle. PEEP also reduces the risk of oxygen toxicity. Some patients will conditions that make the lungs stiff (COPD) required higher levels of PEEP to prevent alveolar collapse.
Impaired Spontaneous Ventilation
Definition: Decreased energy reserves result in an individual’s inability to maintain breathing adequate to support life.
Related Factors: Metabolic factors, Respiratory muscle fatigue
Defining Characteristics:
- Apprehension/Decreased cooperation
- Hypoxemia
- Hypercapnia
- Dyspnea and use of accessory msucles
- Increased HR
Nursing Interventions:
- Collaborate regarding possible intubation/ventilation. Integrate advanced directives
- Assess and respond to sub/obj changes in resp. status
- Assess for hx of chronic resp. disorders when administering O2
- Once intubated, secure ET tube in place and ensure placement by auscultating bilateral BS and use of CO2 detector (ETCO2)
- Ensure ventilator settings are appropriate to meet patient’s ventilation requirments
- Suction prn with hyperoxygenation and hyperventilation
- Ensure activation of all monitor alarms each shift
- Respond to vent alarms promptly. If unable to locate source of alarm, use manual rescusitation bag to ventilate patient while waiting on assistance
- Administer analgesics/sedatives prn
- Analyze and respond to ABGs, end-tidal CO2 levels, pulse oximetry values
- Use effective means of nonverbal communicaiton
- Reposition ET tube from sid eto side every 24 hours
- Implement steps to prevent ventilator associated pneumonia (VAP) including HOB elevated to 30-40 degrees, diligent handwashing, routine oral care every 2-4 hours
Dysfunctional Ventilatory Weaning Response
Definition: Inability to adjust to lowered levels of mechanical ventilator suppor that interrupts and prolongs weaning process
Related Factors:
- Physiological Factors
- Ineffective airway clearance
- Inadequate nutrition
- Pain
- Psychological FActors
- Knowledge deficit
- Decreased motivation
- Anxiety
Defining Characteristics:
- Changes or decline in patient’s CV, respiratory, and/or neuro assessments that are then classified as mild, moderate, or severe dysfunctional ventilation weaning response
Nursing Interventions:
- Assess readiness: resolution of initial medical problem that led to vent. depedence, hemodynamic stability, adequate nutritional status, physical comfort, psychological readiness
- Collaborate to develop weaning plan with a timeline and goals
- Provide safe/comfortable environment, stay with patient during weaning process
- Coordinate pain and sedative medications to minimize sedative effects
- Schedule weaning for periods when patient is most rested
- Involve patient in plan
- Coach through episodes of increased anxiety, positive reinforcement
- Monitor sub and obj data throughout weaning to determine intolerance:
- Tachypnea, dyspnea, chest asymmetry, aggitation/mental status changes, O2 sat less than 90%, change in HR, BP or onset of new dysrhythmias
9.
- Tachypnea, dyspnea, chest asymmetry, aggitation/mental status changes, O2 sat less than 90%, change in HR, BP or onset of new dysrhythmias
What does restlessness indicate?
Hypoxemia
What does lethargy indicate?
Hypercapnia
What does it mean when breath sounds are heard on one side of the chest and not the other?
- ET tube displacement (R. mainstream bronchus)
- Pneumothorax (when BS absent on left)
How is a respiratory rate assessed when a patient is on a ventilator?
count for one full minute
How is the location of the ET tube checked for accuracy?
BS, CXR, ETCO2 and check centimeter mark from teeth on ET tube
How are ventilator checks performed?
- FIO2
- Mode
- Rate
- Temp
- Alarms on
- Check Settings
