VENTELATOR
SETTINGS
·
TIDAL VOLUME
·
PEEP
·
MODE
·
RATE
·
FiO2
Tidal volume (symbol VT or TV) is the lung volume representing the normal volume of air displaced between normal inhalation and exhalation when extra effort is not applied. In a healthy, young human adult, tidal volume is approximately 500 ml per inspiration or 7 ml/kg of body mass.
Respiratory Rate (RR): This is the set rate for delivering breaths per minute (bpm). For example, if the set rate is 15 then the delivery is 15 bpm or 1 breath every 4 seconds. This is called time-triggered control
PEEP [POSITIVE
END EXPIRATORY PRESSURE]
·
PRESSURE
GIVEN IN EXPIRATORY PHASE TO PREVENT CLOSURE OF THE ALVEOLI AND ALLOW INCREASED
TIME FOR OXYGEN EXCHANGE.
·
NORMAL
PEEP=5CM H2O – 20CM H2O
FIO2:The fraction of inspired oxygen (FiO2) is the concentration of oxygen in the gas mixture.
FiO2 is typically maintained below 0.5 [50%] even
with mechanical ventilation, to avoid oxygen toxicity.
MODES OF VENTILATION
Controlled Ventilation
• Vent initiates all
breaths at a pre-set rate and tidal volume
• Vent will block any spontaneous
breaths
• Used mainly in the OR for paralyzed and sedated patients.
Assist Control (A/C)
• Vent will allow a patient to initiate a breath and then
vent will deliver a pre-set tidal volume
• Machine set at a
minimum rate so apnea will not occur if the patient does not initiate a breath
Disadvantages:
• Hyperventilation if
patient has increased respiratory rate (can lead to respiratory alkalosis)
• Vent dysynchrony, breath-stacking
Synchronized Intermittent Ventilation (SIMV)
• Similar to A/C, but patients can take own breaths with
their own TV between mechanically assisted breaths
• Can be used as a primary mode or a weaning mode
• May lead to a low respiratory rate in a patient who does
not initiate breaths if set rate is low
Pressure Support Ventilation (PSV) / “spontaneous
mode”
• Pt initiates breath & vent delivers a pre-set
inspiratory pressure to help overcome airway resistance and keeps airways open
• Patient controls the rate, tidal volume, and minute
ventilation
• Tidal volume is
variable
• Can be used in conjunction with SIMV or CPAP settings
Continuous Positive Airway Pressure (CPAP)
• Positive airway pressure provided during both inspiration
and expiration
• Vent provides O2
and alarms, but no respirations
• Improves gas
exchange and oxygenation in patients able to breathe on their own
• Can also be used non-invasively via a face or nasal mask
for patients with sleep apnea
Bi-Level Positive
Airway pressure (BiPAP)
• Delivered by mask, not through an airway
• Similar to CPAP , but can be set at one pressure for inhalation
and another for exhalation.
• Used in sleep apnea , but also has been found to be useful
in patients with CHF and respiratory failure to avoid intubation
Ventilator Alarms
High Pressure Alarm
• Secretions/ needs to be suctioned (common)
• Kinked tubing/ malposition of ETT
• Pt biting tube/ fighting ventilator
• Water in tubing (common)
• Bronchospasm
• Pneumothorax
• Decreased compliance (i.e.ARDS)
Low Pressure Alarm
• Tubing disconnect from ventilator
• Leak in cuff or tubing connections (if patient can talk
around trach, a leak in the cuff is probable)
• Extubation
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