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
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.
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
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
- Apprehension/Decreased cooperation
- Dyspnea and use of accessory msucles
- Increased HR
- 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
- Physiological Factors
- Ineffective airway clearance
- Inadequate nutrition
- Psychological FActors
- Knowledge deficit
- Decreased motivation
- 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
- 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
What does restlessness indicate?
What does lethargy indicate?
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?
- Alarms on
- Check Settings
How is oral care provided to a patient on a ventialtor?
Two people reposition tube, lubricate lips
What must always be done before a patient is repositioned
Empty water so it is not instilled into patient upon repositioning. Raise the HOB to 30 degrees, side rails up at all times
In the absence of an in-line water trap you would detach vent tubing from patient and empty water into discard container, NOT back into humidification reservoir. Water emptied back into reservoir carry bacteria which will breed in reservoir.
What are the nutritional needs of a mechanically ventilated paitent?
Needs calories (TPN) but not too many carbs because it will increase CO2
How would you respond to ventilator alarms?
- Assess patient
- If the problem is not apparent/easily corrected, disconnect patient from machine and connect ambu bag with O2 supply and bag until help arrives
Sodium and Water Imbalance
From Mechancial Ventilation
- Decreased urinary output
- Decreased renal perfusion
- Increased renin and aldosterone levels (BP)
- Increased sodium and water retention
from mechanical ventilation
- Increased intrathoracic pressure
- Decreased venous return
- Decreased cardiac output and BP
from mechanical ventilation
- Increased lung infation pressures lead to increased risk of barotrauma and pneumothorax
- Increased risk of alveolar hypoventilation OR alveolar hyperventilation
- Increased risk of ventilator associated pneumonia (VAP)
from mechanical ventilation
- Increased need to feel safe
- Increased need for nurses to communicate creatively, encourage hope, and build trust
- Patients should have increased involvement in decision making
with mechanical ventilation
- Increased risk for problems associated with mobility
- Increased need for adequate analgesia, nutrition, and passive and active exercises
with mechanical ventilation
- Increased risk of stress ulcers and GI bleeds due to stress and ischemia of the intestinal mucosa
- Decreases peristalsis
- Increases CO2 levels due to carbohydrate metabolism
with mechanical ventilation
- Increase in cerebral volume
- Increased intrcranial pressue
Nursing Responsibilities of Patients Receiving Mechanical Ventilation
- Monitor VS q 2-4hr
- Assess lung sounds q 2-4 hr
- Reposition the patient q 2 hr
- Be aware of ventilator settings to assist in planning care
- Suction only as often as the patient requires, using sterile technique
- Restoack suction supplies q shift prn
- Empty condensed water from ventilator tubing q 1-2 hours and before repositioning patients, but do not allow the condensation to return to the humidification reservoir
- Keep ambu bag connected to oxygen source at bedside at all times
- Keep extra tracheostomy tubes at the besides (for patients with trachs)
- Do not face fans directed at the patient
- Remember to communicate with the patient, anticipating and providing for psychological needs
Tips for Ventilator Alarms
- Make sure alarms are set at all times and chart. Set alarm volume at 100%
- Pause (to temporarily silence) but do not turn off ventilator alarms. Most deaths from accidental disconnections occur when the alarm is turned off.
- Respond immediately to alarms, making sure to look at the patient first and then check the ventilator to determine the reason for the alarm. If the patient is in distress, you may need to call for help
- Manually ventilate the patient with a bag-mask-valve device connected to an oxygen source at 100% if you cannot immediately determine the solution to the alarm situation. When an alarm sounds the ventilator may stop administering breaths. You will need to call for help.
Low pressure alarms
- Accidental disconnection from ventilator - check trach/ET connection with vent. tuving
- Inadequate returning volume sensed by machine during inhalation - check cuff integrity for deflation; determine if air is leaking out around the patient's trach/ET
High Pressure Alarm
- Patient coughing during delivery of a breath - assess need for suctioning, airway congestion
- Kink in tuving from ventilator to patient
- Worsening pulmonary congestion, worsening disease process, bronchospasm
Machine may have trouble delivering the prescribed:
- tidal volume
Ventilator-associated pneumonia d/t
- ET tubal trach bypasses
- Upper airway defenses
- Poor nutritional state
- Underlying problem
Interventions to reduce incidence of VAP
- Elevate HOB to 30 degrees
- Daily sedation vacation for daily assessment of readiness to extubate
- Peptic ulcer disease (PUD) prophylaxis to reduce risk of translocation of bacteria from GI tract d/t bleeding/ulcers
- Deep vein thrombosis (DVT) prevention
- Keep resp. equipement sterile
- wash hands
- proper room ventilation
- decrease environmental traffic
- suctioning if patient not able to cough
- oral care every 2 hours
- reposition every 2 hours
- hold tube feed when patient is supine
- getting rid of condensation in tubing (do before moving/turning)
- use sterile solution for irrigation
- keep ambu bags close/disinfected
S/Sx of intolerance
- Sustained desaturation
- Sustained V less than 5mL/kg
- Mental status changes
- PaCO2 increased
- PaO2 decreased
- O2 sat decreased
- Changes in HR or BP
T or F: Mechanical ventilators can be used to provide oxygenation without ventilation
True. CPAP is one such mode.
T or F: PEEP helps to prevent alveolar overinflation
False. PEEP helps prevent alveolar collapse
T or F: Barotrauma can result in a pnemothorax
True. Air can escape into the pleural space from ruptured alveoli (barotrauma)
T or F: Decreased renal perfusion can lead to increased renin and aldosterone levels, causing sodium and water retention
True. Sodium and water imabances are complications of positive pressure ventilation.
T or F: Mechanical ventilation through an artifical airway is accomplished through negative pressue.
False. Mechanical ventilation through an artificial airway is accomplished through positive pressue.
T or F: Increased ventilation due to increased RR or tidal volume can cause increased carbon dioxide levels
False. Increased carbon dioxide levels can occur from hypoventilation due to decreased RR or tidal volume
T or F: FiO2 is the percentage of oxygen in which the ventilator is set to deliver to the patient.
True. FiO2 may be set between 21% and 100% and is usually adjusted to maintain PaO2 greater than 60 mm Hg or SpO2 levels greater than 90%
Do ventilator patients have to stay on bedrest?
Does increased intrathoracic pressure result in decreased cardiac output?
Yes. Increased intrathoracic pressure causes decreased venous return to the heart, thus reducing cardiac output and BP