Artificial ventilation, also known as mechanical ventilation, is a medical intervention used to assist or replace spontaneous breathing in patients who are unable to breathe adequately on their own. This can be necessary in various clinical scenarios, such as during surgery, in critically ill patients, or those with respiratory failure. Here's an overview of artificial ventilation and related equipment:
2. Contents
• ArtificialVentilation and related equipment's
• Physiology of IPPV
• Principles of mechanical ventilation.
• Various modes of IPPV
• Operating roomVentilators
• Complications in patients onVentilators
• General care of patient onVentilator
• Disinfection and sterilization of ventilators
3. ArtificialVentilation
• Artificial ventilation, also known as mechanical ventilation, is a medical intervention used
to assist or replace spontaneous breathing in patients who are unable to breathe
adequately on their own.This can be necessary in various clinical scenarios, such as during
surgery, in critically ill patients, or those with respiratory failure. Here's an overview of
artificial ventilation and related equipment:
• 1.Ventilators:
• Definition: Mechanical ventilators are devices that deliver breaths to a patient by positive
pressure, helping to maintain an adequate exchange of oxygen and carbon dioxide in the
lungs.
• Modes ofVentilation:Ventilators offer various modes, including assist-control, pressure
support, and synchronized intermittent mandatory ventilation (SIMV), among others.
• Settings: Parameters such as tidal volume, respiratory rate, and positive end-expiratory
pressure (PEEP) are adjustable to meet the patient's specific needs.
4. • EndotrachealTubes (ETTs) andTracheostomyTubes:
• ETTs:These tubes are inserted through the mouth or nose into the trachea and are
connected to the ventilator.They secure the airway and allow the delivery of positive
pressure ventilation.
• TracheostomyTubes: Similar to ETTs, these tubes are inserted through a surgically
created opening in the neck (tracheostomy) and are used for long-term ventilation.
• 3.Ventilator Circuits:
• Breathing Circuits:These connect the ventilator to the patient and consist of tubing,
connectors, and exhalation valves.They come in various designs, including heated circuits
to maintain temperature and humidity.
• 4. Humidifiers:
• Heated Humidifiers: Used to add moisture to the inspired air to prevent drying of the
airways, especially during prolonged ventilation.
5. • Filters:
• Bacterial/Viral Filters: Placed in the ventilator circuit to prevent the transmission
of microorganisms between patients and the ventilator.
• 6. Monitoring Devices:
• Pulse Oximeter: Measures oxygen saturation in the blood.
• Capnography: Monitors the concentration of carbon dioxide in exhaled air.
• Pressure andVolume Monitoring: Monitors airway pressures and tidal volumes to
ensure safe ventilation.
• 7. Alarms:
• Ventilators are equipped with alarms to alert healthcare providers to changes in
parameters, such as high or low airway pressure, disconnection, or low oxygen
saturation.
6. • Modes ofVentilation:
• Volume Control: Delivers a set tidal volume with each breath.
• Pressure Control: Maintains a set airway pressure during inspiration.
• Pressure Support: Provides support to spontaneous breaths initiated by the patient.
• 9. Weaning Protocols:
• Gradual reduction of ventilatory support as the patient's respiratory function improves.
• 10.TransportVentilators:
• Portable ventilators designed for use during patient transport within a healthcare facility.
• 11. High-FrequencyVentilation:
• Delivers very rapid breaths at a high frequency, often used in specific cases of respiratory
failure.
7. • Extracorporeal Membrane Oxygenation (ECMO):
• A more advanced form of respiratory support involving the use of an external
circuit to oxygenate and remove carbon dioxide from the blood.
• Artificial ventilation is a complex and highly specialized field within critical care
and anesthesiology, requiring careful monitoring and adjustment to meet
individual patient needs while minimizing potential complications.The choice of
equipment and ventilation strategy depends on the patient's condition, the
underlying cause of respiratory failure, and other clinical factors.
8. Physiology of IPPV
• Intermittent Positive PressureVentilation (IPPV) is a ventilation technique used in
mechanical ventilation to assist or replace spontaneous breathing. It involves
delivering breaths to the patient using positive pressure, and it plays a crucial role
in managing patients with respiratory failure or those undergoing surgery.The
physiology of IPPV involves various aspects, including lung mechanics, gas
exchange, and cardiovascular effects. Here's an overview of the key physiological
aspects of IPPV:
9. • Lung Mechanics:
• TidalVolume (Vt): IPPV delivers a predetermined tidal volume to the patient
during each breath.Tidal volume is the volume of air moved in and out of the
lungs with each breath.
• Positive End-Expiratory Pressure (PEEP): PEEP is a positive pressure maintained
in the airways at the end of expiration. It prevents alveolar collapse, improves
oxygenation, and may reduce the work of breathing.
• Airway Resistance: IPPV can affect airway resistance, particularly if there is
narrowing or obstruction in the airways. Higher airway resistance may increase
the work of breathing.
• Compliance: Compliance refers to the elasticity or distensibility of the lungs and
chest wall. Changes in lung compliance can impact the effectiveness of IPPV.
10. • Gas Exchange:
• Oxygenation: Positive pressure ventilation helps improve oxygenation by
delivering a controlled and increased concentration of oxygen to the alveoli.
• Carbon Dioxide Elimination: IPPV assists in removing carbon dioxide (CO2) from
the body by providing adequate ventilation.The respiratory rate and tidal volume
are adjusted to maintain appropriate CO2 levels.
• Alveolar Recruitment: PEEP can recruit collapsed alveoli, enhancing gas
exchange by improving lung compliance and ventilation-perfusion matching.
11. • Cardiovascular Effects:
• Intrathoracic Pressure Changes: Positive pressure ventilation alters intrathoracic
pressures. During inspiration, positive pressure in the airways may impede venous
return to the heart, affecting cardiac output.This is known as the positive
intrathoracic pressure effect.
• Hemodynamic Effects: Changes in venous return, right ventricular function, and
systemic blood pressure can occur.These effects are influenced by factors such as
the patient's volume status, cardiac function, and the level of positive end-
expiratory pressure (PEEP) applied.
12. • Barotrauma andVolutrauma:
• Barotrauma: Excessive airway pressure during IPPV can lead to barotrauma,
causing damage to the lung tissue. Monitoring and limiting peak airway pressures
are essential to prevent this complication.
• Volutrauma: Delivery of large tidal volumes can cause volutrauma, contributing to
lung injury. Lung-protective ventilation strategies aim to minimize volutrauma.
13. • Ventilator-Induced Lung Injury (VILI):
• VILI encompasses various types of lung injury caused by mechanical ventilation.
Strategies such as lung-protective ventilation aim to minimize the risk ofVILI.
14. Principles of Mechanical ventilation
• Mechanical ventilation is a life-saving intervention that provides respiratory
support to patients who are unable to maintain adequate ventilation on their own.
The principles of mechanical ventilation involve various aspects, including
ventilator settings, monitoring, and strategies to optimize patient outcomes. Here
are some key principles of mechanical ventilation:
• Patient Assessment:
• A thorough assessment of the patient's respiratory status, underlying pathology, and
overall clinical condition is essential to determine the appropriate ventilation strategy.
• Indications for Mechanical Ventilation:
• Mechanical ventilation is indicated when a patient is unable to maintain adequate
oxygenation or eliminate carbon dioxide effectively. Common indications include
respiratory failure, neuromuscular disorders, and surgical procedures.
15. • Ventilator Modes:
• Selecting the appropriate ventilator mode depends on the patient's condition.Common
modes include assist-control ventilation, pressure support ventilation, synchronized
intermittent mandatory ventilation (SIMV), and others.The choice is based on the need
for full or partial ventilatory support.
• TidalVolume and Respiratory Rate:
• Tidal volume (Vt) is the volume of air delivered with each breath. It is adjusted based on
the patient's size and respiratory needs. Respiratory rate (RR) determines the number of
breaths delivered per minute.
• Positive End-Expiratory Pressure (PEEP):
• PEEP is positive pressure maintained in the airways at the end of expiration. It prevents
alveolar collapse, improves oxygenation, and can enhance lung compliance. However,
excessive PEEP may have hemodynamic consequences.
16. • Fraction of Inspired Oxygen (FiO2):
• FiO2 is the concentration of oxygen delivered by the ventilator. It is adjusted to maintain
adequate oxygen saturation while minimizing the risk of oxygen toxicity.
• I:E Ratio (Inspiratory to Expiratory Ratio):
• The I:E ratio is the ratio of the duration of inspiration to expiration. It can be adjusted to
influence gas exchange and respiratory mechanics.
• Monitoring:
• Continuous monitoring is essential. Parameters include oxygen saturation (SpO2), end-
tidal carbon dioxide (EtCO2), airway pressures, and respiratory mechanics.
Hemodynamic monitoring is also crucial to assess the cardiovascular impact of
ventilation.
• Lung-Protective Ventilation:
• Lung-protective strategies aim to minimize ventilator-induced lung injury (VILI).This
involves using lower tidal volumes and limiting plateau pressures, especially in patients
with acute respiratory distress syndrome (ARDS).
17. • Weaning Protocols:
• Weaning involves gradually reducing ventilatory support as the patient's
respiratory function improves. Successful weaning requires assessment of
readiness and a stepwise approach.
• Humidification and Airway Management:
• Adequate humidification prevents drying of the airways. Proper airway
management, including endotracheal tube care and suctioning, is crucial to
prevent complications.
• Alarm Management:
• Alarms on the ventilator alert healthcare providers to changes in parameters.
Effective alarm management ensures timely response to issues such as
disconnection, high or low pressures, and low oxygen saturation.
• Patient-Ventilator Synchrony:
• Ensuring synchrony between the patient's efforts to breathe and the ventilator's
delivery of breaths is important for patient comfort and optimal ventilation.
18. Various modes of IPPV
• Intermittent Positive PressureVentilation (IPPV), also known as controlled mechanical
ventilation, encompasses various ventilation modes that provide breaths at a set
frequency and tidal volume. Each mode has specific characteristics and is chosen based on
the patient's needs and clinical condition. Here are some common modes of IPPV:
• Assist-ControlVentilation (ACV):
• Description: ACV delivers a preset tidal volume at a set rate. Patients can trigger additional
breaths (assisted breaths) if they initiate spontaneous efforts.
• Indication: Commonly used for patients who require full ventilatory support.
• Synchronized Intermittent MandatoryVentilation (SIMV):
• Description: SIMV delivers mandatory breaths at a set rate, but the patient can also initiate
spontaneous breaths between mandatory breaths.The ventilator synchronizes with the
patient's efforts.
• Indication: Used for patients who require partial ventilatory support, allowing for some
spontaneous breathing.
19. • Pressure SupportVentilation (PSV):
• Description: PSV delivers support during spontaneous breaths by applying positive
pressure.The patient initiates and controls the rate and depth of breathing.
• Indication:Typically used as a weaning mode to support patients during the transition
to spontaneous breathing.
• Volume Support (VS):
• Description: Similar to PSV,VS provides support during spontaneous breaths, but the
ventilator delivers a preset tidal volume.
• Indication: Used in patients transitioning from controlled to spontaneous ventilation.
• Pressure ControlVentilation (PCV):
• Description: PCV delivers breaths at a set pressure, and the tidal volume varies based
on lung compliance. Inspiratory time is controlled, and the patient can trigger breaths.
• Indication: May be used in patients with varying lung compliance and to limit peak
inspiratory pressures.
20. • Pressure-Regulated Volume Control (PRVC):
• Description: PRVC combines pressure and volume control.The ventilator adjusts
inspiratory pressure to achieve a target tidal volume.
• Indication: Aims to provide consistent tidal volumes while minimizing barotrauma.
• Inverse Ratio Ventilation (IRV):
• Description: IRV uses an inspiratory-to-expiratory (I:E) ratio greater than 1:1.This mode
may be used to improve oxygenation in certain cases.
• Indication:Typically used in patients with severe hypoxemia, such as those with ARDS.
• Airway Pressure ReleaseVentilation (APRV):
• Description:APRV maintains a high continuous positive airway pressure (CPAP) with
brief releases to allow for spontaneous ventilation.
• Indication: Used in patients with acute respiratory distress syndrome (ARDS) or other
conditions requiring lung recruitment.
21. • High-Frequency Oscillatory Ventilation (HFOV):
• Description: HFOV delivers very rapid, small tidal volume breaths at high frequencies. It
is used to minimize barotrauma.
• Indication: Used in severe respiratory distress where traditional ventilation may be
harmful.
• Neutrally AdjustedVentilatory Assist (NAVA):
• Description: NAVA uses the patient's diaphragmatic electrical activity to trigger and
cycle the ventilator.
• Indication: Allows for patient-ventilator synchrony and may be used in specific cases of
respiratory failure.
22. • Operating room ventilators, also known as anesthesia ventilators or anesthesia machines,
are essential equipment used during surgical procedures to assist or control a patient's
ventilation.These ventilators are specifically designed for use in the operating room
environment and are an integral part of the anesthesia delivery system. Here are some key
features and components of operating room ventilators:
• Integrated Anesthesia Machine:
• Operating room ventilators are often part of a comprehensive anesthesia machine that
includes a vaporizer for delivering anesthetic gases, a breathing system, and monitoring
devices.
• Ventilation Modes:
• These ventilators offer various ventilation modes to suit different patient needs. Common
modes include volume-controlled ventilation, pressure-controlled ventilation, and pressure
support ventilation.
• TidalVolume and Respiratory Rate:
• Anesthesia ventilators allow the adjustment of tidal volume (Vt) and respiratory rate (RR) to
provide controlled ventilation to the patient.
23. • Oxygen Concentration (FiO2):
• The FiO2, or fraction of inspired oxygen, can be adjusted to maintain the desired oxygen
concentration during the procedure.
• Positive End-Expiratory Pressure (PEEP):
• Some ventilators offer the option to apply PEEP to prevent alveolar collapse and
improve oxygenation.
• Alarms and Safety Features:
• Operating room ventilators are equipped with alarms to alert anesthesia providers to
issues such as low oxygen concentration, high or low airway pressure, and
disconnection. Safety features are crucial for patient well-being.
• Mechanical Pneumatic System:
• Traditional operating room ventilators use a mechanical pneumatic system driven by
compressed gas sources to deliver breaths to the patient.
24. • Ventilator Controls and Interfaces:
• The ventilator controls are typically integrated into the anesthesia machine's user interface. Anesthesia
providers can adjust settings and monitor patient parameters through a central control panel.
• Breathing Circuits:
• Anesthesia machines are equipped with breathing circuits that connect the ventilator to the patient.These
circuits may include components such as inspiratory and expiratory valves, carbon dioxide absorbers, and
patient connectors.
• Hypoxic Guard Systems:
• To prevent the delivery of hypoxic gas mixtures, operating room ventilators often incorporate hypoxic guard
systems.These systems monitor and control the inspired oxygen concentration to ensure patient safety.
• VentilatorWaveforms:
• Some modern operating room ventilators display graphical representations of pressure, flow, and volume
waveforms, providing valuable information about the patient's respiratory status.
• Intuitive User Interface:
• Anesthesia machines are designed with user-friendly interfaces to facilitate ease of use for anesthesia
providers.This includes touch screens, visual displays, and audible alarms.
• ModernVentilatorTechnology:
• Advances in technology have led to the development of sophisticated ventilators with features like lung
protective ventilation strategies, advanced monitoring capabilities, and integration with electronic medical
records.
25. Complications in patients onVentilator
• Patients on ventilators, especially those requiring prolonged mechanical ventilation, are at
risk for various complications.These complications can arise from the mechanical
ventilation itself, the underlying medical conditions, or a combination of factors. Here are
some common complications associated with patients on ventilators:
• Ventilator-Associated Pneumonia (VAP):
• Description: Infections of the lower respiratory tract that occur after 48 hours of mechanical
ventilation.
• Risk Factors: Prolonged ventilation, immunosuppression, and the use of invasive devices.
• Prevention: Strict infection control measures, head-of-bed elevation, and oral care.
• Barotrauma andVolutrauma:
• Barotrauma: Damage to the lungs due to high airway pressures, leading to conditions like
pneumothorax or subcutaneous emphysema.
• Volutrauma: Lung injury caused by the use of high tidal volumes, resulting in alveolar
overdistension.
• Prevention: Lung-protective ventilation strategies, monitoring airway pressures.
26. • Atelectrauma:
• Description: Repeated opening and closing of alveoli, leading to inflammation and lung
injury.
• Risk Factors: High tidal volumes and low positive end-expiratory pressure (PEEP).
• Prevention: Use of appropriate PEEP to prevent alveolar collapse.
• Ventilator-Induced Lung Injury (VILI):
• Description: Lung injury caused by mechanical ventilation, including barotrauma,
volutrauma, and atelectrauma.
• Prevention: Lung-protective ventilation strategies, minimizing high pressures and
volumes.
• OxygenToxicity:
• Description: Cellular damage due to prolonged exposure to high levels of oxygen.
• Risk Factors: Prolonged use of high FiO2.
• Prevention: Adjusting oxygen concentrations based on patient needs, maintaining
conservative oxygen therapy.
27. • Ventilator-Induced Diaphragmatic Dysfunction (VIDD):
• Description:Weakness and atrophy of the diaphragm muscles due to prolonged
mechanical ventilation.
• Risk Factors: Long duration of ventilation, high levels of respiratory support.
• Prevention: Early initiation of spontaneous breathing trials, minimizing sedation.
• Ventilator-Associated Events (VAEs):
• Description: Adverse events associated with mechanical ventilation, includingVAP and
respiratory failure.
• Prevention: Adherence to evidence-based ventilator management protocols, timely
weaning.
• Hemodynamic Complications:
• Description: Changes in blood pressure and cardiac output due to alterations in
intrathoracic pressure during ventilation.
• Risk Factors: High levels of PEEP, positive pressure ventilation.
• Prevention: Monitoring hemodynamic parameters, adjusting ventilator settings
cautiously.
• .
28. • Psychological Complications:
• Description: Anxiety, delirium, and post-traumatic stress disorder (PTSD) associated
with prolonged mechanical ventilation and sedation.
• Risk Factors: Duration of ventilation, use of sedatives.
• Prevention: Early mobilization, minimizing sedation, addressing psychological well-
being Ventilator Disconnection:
• Description: Unintentional disconnection from the ventilator, leading to hypoxemia.
• Risk Factors: Improper securing of endotracheal tubes or breathing circuits.
• Prevention: Regular monitoring, securing connections, use of ventilator alarms.
• Endotracheal Tube-related Complications:
• Description: Complications associated with the presence of an endotracheal tube,
including mucosal damage, infection, and unplanned extubation.
• Prevention: Proper securing of the tube, regular assessment, and care of the airway.
29. • Caring for a patient on a ventilator, also known as mechanical ventilation, requires a
multidisciplinary approach involving healthcare professionals such as physicians, nurses,
respiratory therapists, and other support staff. Here are general considerations for the
care of a patient on a ventilator:
• Monitoring:
• Continuous monitoring of vital signs, including heart rate, blood pressure, respiratory rate, and
oxygen saturation.
• Regular assessment of the patient's level of consciousness and neurological status.
• Ventilator Settings:
• Ensure that the ventilator settings are appropriate for the patient's condition, and monitor
parameters such as tidal volume, respiratory rate, and positive end-expiratory pressure
(PEEP).
• Regularly assess and adjust ventilator settings based on the patient's response and clinical
condition.
30. • Airway Management:
• Maintain a secure airway, ensuring the endotracheal tube or tracheostomy is properly in place.
• Suction the airway as needed to clear secretions and prevent obstruction.
• Oxygenation andVentilation:
• Monitor and adjust oxygen levels to maintain adequate oxygenation and prevent hypoxemia.
• Ensure proper ventilation to prevent hypercapnia.
• Chest Physiotherapy:
• Perform chest physiotherapy and respiratory treatments as needed to help mobilize
secretions and improve lung function.
• Infection Control:
• Implement strict infection control measures to prevent ventilator-associated pneumonia
(VAP).
• Regularly assess and maintain the cleanliness of ventilator equipment.
31. • Positioning:
• Change the patient's position regularly to prevent complications such as pressure sores and improve
ventilation.
• Elevate the head of the bed to enhance lung expansion.
• Nutritional Support:
• Provide appropriate nutritional support to meet the patient's energy and nutritional requirements.
• Consider enteral or parenteral nutrition as needed.
• Pain Management and Sedation:
• Manage pain and discomfort with appropriate analgesics.
• Adjust sedation levels to maintain patient comfort and facilitate synchronization with the ventilator.
• Communication and Psychosocial Support:
• Establish a means of communication with the patient (e.g., writing, gestures) if they are conscious and able
to participate.
• Provide emotional support to both the patient and their family, and involve them in decision-making when
possible.
• Weaning and Rehabilitation:
• Initiate a weaning protocol when appropriate, gradually reducing ventilator support.
• Plan and implement rehabilitation strategies to promote mobility and prevent complications associated with
immobility.
32. • Disinfection and sterilization of ventilators are critical processes to prevent the transmission
of infections among patients and maintain the safety of healthcare settings. Proper cleaning
and maintenance procedures are essential to ensure that ventilator equipment remains free
of pathogens. Here are general guidelines for disinfection and sterilization of ventilators:
• Follow Manufacturer's Instructions:
• Always adhere to the manufacturer's guidelines for cleaning, disinfecting, and sterilizing the
specific model of ventilator.These instructions provide essential information about compatible
cleaning agents and procedures.
• Hand Hygiene:
• Perform thorough hand hygiene before and after handling ventilator equipment to prevent the
spread of infections.
• Personal Protective Equipment (PPE):
• Wear appropriate PPE, including gloves and, if necessary, a gown and mask, when handling and
cleaning ventilators.
33. • Daily Cleaning:
• Perform routine cleaning of the external surfaces of the ventilator using a mild detergent or
disinfectant wipes.
• Pay special attention to high-touch areas such as buttons, knobs, and touchscreens.
• Disposable Components:
• Replace or dispose of single-use components (e.g., tubing, filters, humidifier chambers)
according to the manufacturer's recommendations.
• Ventilator Circuit Cleaning:
• Regularly clean and disinfect reusable ventilator circuits according to the manufacturer's
instructions.
• Ensure proper drying of components before reuse.
34. • HumidifierCleaning:
• Clean and disinfect humidifier chambers regularly to prevent the growth of microorganisms. Use appropriate
disinfectants and follow the manufacturer's recommendations.
• Filter Replacement:
• Replace filters as recommended by the manufacturer to maintain optimal air quality and prevent the spread of
contaminants.
• Sterilization of Components:
• For components that require sterilization, follow the manufacturer's guidelines for autoclaving or other
sterilization methods.
• Ventilator Room Cleaning:
• Ensure that the ventilator room or area is regularly cleaned and disinfected, paying attention to surfaces and
equipment that may come in contact with the ventilator.
• Documentation:
• Maintain thorough documentation of cleaning and maintenance activities, including the date, time, and the
type of cleaning or disinfection performed.
• StaffTraining:
• Provide training to healthcare personnel responsible for cleaning and maintaining ventilators. Ensure they are
aware of and follow proper protocols.
