NurseReview.Org - Introduction to Mechanical Ventilation

Slide 1: Introduction to Mechanical Ventilation Craig A. Hawkins BS RRT RCP Respiratory Therapy Supervisor Presbyterian Hospital

Slide 2: Indications for Mechanical Ventilation  Impending Respiratory Failure  Acute Respiratory Failure/Arrest  Post-Operatively

Slide 3: Indications for Mechanical Ventilation  Impending Respiratory Failure  Progressively worsening clinical appearance.  Worsening CXR.  Hypoxemic Respiratory Failure.  Hypercapnic Respiratory Failure.

Slide 4: Indications for Mechanical Ventilation  Acute Respiratory Failure/Arrest  Acute change in ABG results  Respiratory Arrest/Status Post CPR  Acute epiglottitis/anaphylaxis

Slide 5: Indications for Mechanical Ventilation  Postoperatively  Oversedation/paralytics  Pain Control  Proper Immobilization

Slide 6: Key Terms in Mechanical Ventilation  Tidal Volume (Vt)  The volume of air inhaled and exhaled from the lungs.  Breaths per Minute (RR, f)  Also known as frequency.  Positive End Expiratory Pressure (PEEP)  Maintenance of above atmospheric pressure at the airway throughout exp. phase.

Slide 7: Key Terms in Mechanical Ventilation  Minute Ventilation (VE)  The total amount of volume moving in and out of the lung in one minute.  Fractional Inspired Oxygen (FiO2)  Correctly written with decimal place (21%- 0.21; 100%-1.0)  Inspiratory:Expiratory Ratio (I:E ratio)  Normal I:E ratio 1:2-3

Slide 8: Negative Pressure Ventilation  Rarely Used; Currently used for patients with neuromuscular diseases.  Thoracic cage is encased where negative pressure is applied across the chest wall.  Generates subatmospheric pressures creating a difference in pressure gradients.  During exhalation, negative pressure is replace by atmospheric pressure allowing the lungs to deflate.

Slide 9: Negative Pressure Ventilation  Types of Negative Pressure Ventilators

Slide 10: Iron Lung circa 1950’s

Slide 11: Modern(ized) Iron Lung

Slide 12: Chest Cuirass

Slide 13: Complications with Negative Pressure Ventilation  Limited access for patient care.  Inability to properly monitor pulmonary mechanics.  Patient discomfort.

Slide 14: Positive Pressure Ventilation  Defined as the application of pressure to the lungs in order to improve gas exchange.  The Lungs are physically filled/ventilated with air using machinery.  Multiple modes, methods, and theory.

Slide 15: Positive Pressure Ventilation  Basically broken into two categories:  Control Modes.  Supportive Modes.

Slide 16: Control Modes of Ventilation  Assist/Control (usually abbreviated A/C also known as Volume Control VC).  Tidal Volume is set and remains constant.  Respiratory Rate is set.  Airway Pressure will vary according to lung compliance.  Ventilator will deliver set volume whether patient triggers a breath or mandatory breath is being delivered.

Slide 17: Control Modes of Ventilation  Pressure Control Ventilation (usually abbreviated PCV or sometimes PCIRV).  Upper Airway Pressure Level is set and remains constant.  Respiratory Rate is set.  Tidal volumes will vary according to lung compliance.  Ventilator will deliver set pressure level whether patient triggers a breath or mandatory breath is being delivered.

Slide 18: Control Modes of Ventilation  Pressure Regulated Volume Control (usually abbreviated PRVC).  Tidal Volume is set, however may or may not remain constant.  Respiratory Rate is set.  Ventilator will deliver volume however volume may decrease according to patient’s lung compliance.  A lung protective mode.

Slide 19: Supportive Modes of Ventilation  Synchronized Intermittent Mandatory Ventilation (usually abbreviated SIMV).  Tidal Volume is set and delivered on each mandatory breath.  Respiratory Rate is set.  When a patient triggers the ventilator spontaneously , the patient receives a Pressure Supported breath.

Slide 20: Supportive Modes of Ventilation  Pressure Support Ventilation (PSV)  Is a strictly patient dependant mode; patient must be breathing spontaneously.  An upper (inspiratory) pressure level is adjusted to provide adequate tidal volumes for each patient triggered breath.  PEEP is also adjusted as an independent pressure from the upper pressure level and is active during expiration.  PSV is a weaning mode.

Slide 21: Supportive Modes of Ventilation  Volume Support (VS)  Is a strictly patient dependant mode; patient must be breathing spontaneously.  Tidal Volume is set.  Each spontaneous breath is supported with dialed volume.

Slide 22: Supportive Modes of Ventilation  Continuous (Constant) Positive Airway Pressure (CPAP)  Is a strictly patient dependant mode; patient must be breathing spontaneously.  Closely resembles Pressure Support, however CPAP is a constant set pressure that does not change during inspiration or expiration.  CPAP is a weaning mode.

Slide 23: Drager Evita II

Slide 24: Puritan Bennett 840

Slide 25: Servo 900c

Slide 26: Servo 300a

Slide 27: Servo i

Slide 28: One of the Most Famous Ventilators

Slide 29: Complications to Mechanical Ventilation  Ventilator Induced Lung Injury (VILI)  Induced by excessive pressure (barotrauma)  Induced by excessive Volume (volutrauma)  Ventilator Associated Pneumonia (VAP)  Most commonly Pseudomonas, Gram Negative Bacilli, and staphylococci.

Slide 30: Ventilatory Discontinuance  Weaning  Process of discontinuing ventilatory support, regardless of the time frame involved.  Categories  Quick removal; routine  More gradual reduction in support (trach collar trials)  Ventilator dependent patients

Slide 31: Ventilatory Discontinuance  Success in discontinuing ventilatory support is related to the patients conditions in four main areas:  Ventilatory workload  Oxygenation status  Cardiovascular function  Psychological factors.

Slide 32: Ventilatory Discontinuance  Common indices in successful weaning: FiO2 < 0.4-0.5 PaO2 > 60 PaO2/FiO2 ratio > 200 PaCO2 < 50 pH > 7.35 RSBI < 100

Slide 33: Questions?