Week 3 Handout Flashcards
What is the Oxygen Analyzer in anesthesia?
The last time the gas mixture gets checked before reaching the patient.
What principle does a Galvanic Fuel Cell operate on?
A chemical reaction that generates an electrical current proportional to oxygen concentration.
What are the advantages of Galvanic Fuel Cells?
- Long Life: Up to 2 years
- Self-Powered: Generate their own current
What are the disadvantages of Galvanic Fuel Cells?
- Slow Response: Slower than paramagnetic devices
- Calibration: Requires regular calibration
In what devices are Galvanic Fuel Cells commonly used?
Portable and lower-cost devices.
What is the principle behind a Paramagnetic Device?
Uses a strong magnetic field to detect oxygen due to its paramagnetic properties.
What are the advantages of Paramagnetic Devices?
- Rapid Response: Quicker response time
- High Accuracy: Generally more accurate
What are the disadvantages of Paramagnetic Devices?
- Cost: More expensive than galvanic fuel cells
- Power Requirement: Requires external power
Where are Paramagnetic Devices commonly found?
High-end anesthesia machines and critical care units.
What are Open Circuits in anesthesia?
One of the simplest forms of anesthesia delivery systems.
What are the basic components of an Open Circuit?
- Fresh gas source
- Delivery system (mask or nasal prongs)
- Unidirectional flow path
What is a key operational feature of Open Circuits?
Exhaled gases are released into the room or captured by a scavenging system.
What are the advantages of Open Circuits?
- Simplicity: Easy to set up
- Rapid Induction and Recovery
- Low Resistance to Breathing
What are the disadvantages of Open Circuits?
- Inefficiency in Gas Usage
- Lack of Control Over Gas Composition
- Risk of Pollution
What are the four stages of anesthesia?
- Stage I: Induction or Analgesia
- Stage II: Excitement or Delirium
- Stage III: Surgical Anesthesia
- Stage IV: Overdose
What characterizes Stage I of anesthesia?
Period from the beginning of anesthesia to the loss of consciousness.
What happens during Stage II of anesthesia?
Involuntary movements, irregular breathing, heightened reflexes occur.
What defines Stage III of anesthesia?
Diminished reflexes and increased muscle relaxation; target stage for surgical procedures.
What is Stage IV of anesthesia?
Marked by severe CNS depression, leading to cessation of spontaneous respiration.
What are Mapleson Circuits used for?
Delivering inhalation anesthesia and preventing rebreathing of expired gases.
What is Fresh Gas Flow (FGF) in Mapleson Circuits?
Critical component that flushes out exhaled gases to prevent rebreathing.
What component does the Bain Circuit feature?
A coaxial design where the fresh gas flow tube is inside the expiratory limb.
What is the function of the Reservoir Bag in Mapleson Circuits?
Monitors the patient’s breathing and assists in manual ventilation.
What is the purpose of the Adjustable Pressure-Limiting (APL) Valve?
Adjusts pressure within the system and is crucial during manual ventilation.
True or False: Mapleson D is efficient for controlled ventilation during general anesthesia.
True
Fill in the blank: The _______ stage of anesthesia is characterized by involuntary movements and irregular breathing.
Stage II
What is the primary advantage of the Bain Circuit for controlled ventilation?
It provides a constant supply of fresh gas while effectively removing exhaled gases.
In which clinical situations is the Bain Circuit commonly used?
- Operating rooms for surgeries requiring controlled ventilation
- Pediatric anesthesia due to its lightweight and compact nature
- Emergency situations because of its simplicity and quick setup.
What is the first step in the Pethick Test for the Bain Circuit?
Connect the Bain circuit to the anesthesia machine with the fresh gas flow turned on.
What should happen to the reservoir bag during the Pethick Test when the patient end is occluded?
The reservoir bag should inflate as a result of the fresh gas flow entering the circuit.
What indicates proper functioning of the Bain Circuit during the Pethick Test?
The bag inflates and remains inflated when the patient end is occluded, and then deflates quickly upon release.
What does it indicate if the reservoir bag does not inflate during the Pethick Test?
It may indicate a problem such as a leak in the circuit, a blockage, or misassembly.
What is the characteristic design of the Mapleson E circuit?
Simple design with no reservoir bag, commonly used in pediatric anesthesia.
What is the primary reliance of the Mapleson E circuit?
It relies heavily on adequate fresh gas flow (FGF) to prevent rebreathing.
How do Mapleson circuits generally work?
They rely on fresh gas flow (FGF) to provide fresh gas during inhalation and push out exhaled gas.
What is the best method for determining the amount of fresh gas flow required in Mapleson circuits?
End-tidal carbon dioxide (EtCO2) monitoring.
Which Mapleson circuit is best for spontaneous ventilation?
Mapleson A.
Which Mapleson circuit is considered best for controlled ventilation?
Mapleson D.
What is Fresh Gas Coupling (FGC) in anesthesia machines?
A mechanism where the fresh gas flow influences the volume of gas delivered to the patient during mechanical ventilation.
What happens to the tidal volume when fresh gas flow is added during mechanical ventilation?
It effectively increases the volume of gas that the patient receives.
What should be monitored to avoid overventilation in low-flow anesthesia?
The actual tidal volume delivered.
What is the formula to estimate the actual tidal volume delivered to the patient?
Actual Tidal Volume = Set Tidal Volume + FGC Effect.
What is the impact of fresh gas flow on tidal volume?
An increase in FGF can artificially inflate the tidal volume.
What is the I:E ratio in mechanical ventilation?
The ratio of time spent in inspiration versus expiration.
How can fresh gas flow affect the I:E ratio?
If FGF increases tidal volume significantly, it might require adjustments in ventilatory settings, including the I:E ratio.
What is the respiratory rate in mechanical ventilation?
The number of breaths delivered to the patient per minute by the ventilator.
What is a key difference between ascending and descending bellows in ventilators?
Ascending bellows are filled from the bottom and lift upward as gas enters.
What safety feature do ascending bellows provide in case of a leak?
They will fail to ascend or will ascend less than expected, indicating a problem.
What is the visual cue for leak detection in ascending bellows?
The bellows will fail to ascend or will ascend less than expected.
This indicates a problem with the anesthesia circuit or the bellows themselves.
How do ascending bellows respond to circuit pressure changes?
A decrease in pressure due to a leak results in the bellows not rising fully or collapsing.
This response is critical for identifying leaks in the system.
What is the filling mechanism for descending bellows?
Descending bellows are filled from the top, with the weight of the bellows assisting in the descent as they fill with gas.
This design is different from ascending bellows.
What safety concern is associated with descending bellows?
A leak may not be immediately apparent, giving a false impression of normal operation.
The bellows can still descend due to gravity even if there is a leak.
What are the clinical implications of ascending bellows?
Easier monitoring for leaks and enhanced patient safety through clear visual signs of system integrity.
This makes it easier for anesthesia providers to respond to issues.
What is the primary mechanism of piston ventilators?
Piston ventilators use an electric motor to drive a piston within a cylinder.
This allows for precise control of tidal volume and ventilation rate.
What is a significant advantage of piston ventilators?
They can accurately deliver set tidal volumes, which is beneficial for pediatric anesthesia.
This precision is crucial for small patients.
What does the feedback mechanism in piston ventilators do?
It adjusts the motor’s action based on the patient’s lung compliance and resistance.
This allows for more tailored ventilation.
What are the five tasks of oxygen in the anesthesia machine?
- Proceeds to the fresh gas flowmeter
- Powers the oxygen flush valve
- Activates the fail-safe mechanism
- Activates the low-pressure alarm
- Compresses the bellows of mechanical ventilators
Each task is critical for the safety and functionality of the anesthesia machine.
Define spontaneous breathing.
Spontaneous breathing refers to the patient’s own respiratory effort without assistance from a mechanical ventilator.
This is crucial for assessing the patient’s respiratory function.
What characterizes assisted breathing?
The patient initiates the breath, and the ventilator provides additional volume or pressure.
This mode supports patients who are unable to breathe adequately on their own.
What is controlled breathing?
Controlled breathing is when the ventilator completely takes over the work of breathing for the patient.
This mode is used in situations where the patient cannot breathe independently.
What are the clinical applications of Controlled Mandatory Ventilation (CMV)?
- Used during deep anesthesia
- Employed in patients with respiratory failure
- Beneficial for neuromuscular disorders
These applications are important for ensuring adequate ventilation.
What is a risk associated with CMV?
Risk of hypoventilation or hyperventilation due to improper ventilator settings.
Careful monitoring is essential to avoid these complications.
What is the weaning process from CMV?
Transitioning to a less controlled mode of ventilation as the patient’s condition improves.
This helps to gradually reduce dependence on mechanical ventilation.
What does Assist Control Ventilation (ACV) provide?
Partial respiratory support for patients who can breathe spontaneously but need assistance.
It is often used during recovery from full support modes.
What is a consideration when using ACV?
Risk of hyperventilation if the patient’s spontaneous breathing rate is high.
Careful monitoring and adjustment are necessary.
What is Synchronized Intermittent Mandatory Ventilation (SIMV) used for?
Weaning from ventilation and providing partial respiratory support for patients capable of spontaneous breathing.
This mode allows patients to gradually take over more of the breathing work.
What is Synchronized Intermittent Mandatory Ventilation (SIMV)?
A mode used in mechanical ventilation that allows patients to gradually take over more of the breathing work.
SIMV is often utilized in the weaning process from mechanical ventilation.
What is a key clinical application of SIMV?
Weaning from ventilation and providing partial respiratory support.
Suitable for patients capable of spontaneous breathing who still require some ventilatory support.
What is a consideration when using SIMV?
Patient-ventilator synchronization is crucial to ensure mandatory breaths are synchronized with spontaneous efforts.
There is a risk of under-ventilation if spontaneous efforts are insufficient.
What does the Pressure Control Ventilation-Volume Guaranteed (PCV-VG) mode ensure?
It guarantees a set volume while dynamically adjusting pressure to meet ventilation needs.
Particularly useful for lung-protective strategies, especially in ARDS patients.
What is a clinical application of PCV-VG?
Lung protective ventilation for patients requiring lung-protective strategies.
Helps prevent excessive airway pressures.
What is a key consideration when using PCV-VG?
Continuous monitoring is necessary to ensure adequate ventilation and avoid excessive pressures.
Balancing pressure and volume is crucial.
What is Pressure Support Ventilation (PSV) commonly used for?
Weaning from mechanical ventilation and supporting spontaneous breathing.
Ideal for patients who can breathe spontaneously but need assistance.
What risk is associated with inadequate pressure support in PSV?
There is a risk of hypoventilation, especially in weak or fatigued patients.
Patient-ventilator synchronization is vital to prevent discomfort.
What is Pressure Support Ventilation with Proportional Assist (PSV-Pro) designed for?
To enhance patient comfort and facilitate weaning by allowing natural breathing.
Best for patients with stable respiratory drive.
What does Continuous Positive Airway Pressure (CPAP) primarily prevent?
Airway collapse, particularly in obstructive sleep apnea (OSA).
Also useful for lung expansion therapy and post-extubation support.
What is a major risk when using CPAP?
The risk of barotrauma due to constant positive pressure.
Adequate spontaneous breathing is required for CPAP effectiveness.
What is Bilevel Positive Airway Pressure (BiPAP) used for?
Commonly used in patients with respiratory failure or COPD who need additional support.
Helps reduce respiratory workload and is often used in home settings.
What is a consideration for BiPAP?
Monitoring is required to ensure patient-ventilator synchrony and adjust settings as needed.
BiPAP is not suitable for patients who cannot initiate their own breaths.
What is Airway Pressure Release Ventilation (APRV) beneficial for?
Managing patients with acute respiratory distress syndrome (ARDS) by maximizing alveolar recruitment.
It may reduce the need for deep sedation.
What is a risk associated with APRV?
Hypoventilation may occur if settings are not properly adjusted.
Requires careful monitoring of oxygenation and ventilation.
What condition is Inverse Ratio Ventilation (IRV) used for?
Refractory hypoxemia in conditions like ARDS.
It helps open collapsed alveoli for enhanced oxygenation.
What is a consideration when using IRV?
Risk of lung injury due to increased airway pressure during prolonged inspiratory phases.
Requires vigilant monitoring of respiratory and hemodynamic parameters.
What is High Frequency Ventilation (HFV) primarily used for?
Lung protection in patients with ARDS or conditions where conventional ventilation is not optimal.
Frequently employed in neonatal care.
What is High Frequency Ventilation (HFV)?
A ventilation mode useful in patients with ARDS or conditions requiring lung protection.
In which clinical situations is HFV particularly useful?
- ARDS patients
- Pediatric and neonatal care
- Airway surgery
What is a key consideration when using HFV regarding patient monitoring?
Careful monitoring is required to ensure adequate ventilation and oxygenation.
What impact does continuous distending pressure from HFV have?
It can affect hemodynamics, necessitating close cardiovascular monitoring.
What type of equipment is required for HFV?
Specific ventilators and expertise for application and management.
What is important to consider when transitioning from HFV to conventional ventilation?
The transition should be gradual, considering the patient’s lung mechanics and overall stability.
What principle does Jet Ventilation utilize?
Giovanni Battista Venturi’s principle of reduced pressure at a tube’s narrowing.
What is the purpose of Airway Exchange Catheters (AECs)?
To facilitate changing or removing endotracheal tubes and to deliver jet ventilation or oxygen insufflation.
Where should AECs be placed and why?
Proximally to the carina to avoid trauma.
What is Needle Cricothyrotomy with Transtracheal Jet Ventilation (TTJV)?
An emergency technique for ‘cannot intubate, cannot oxygenate’ scenarios.
What is the typical respiratory rate for TTJV?
~8-10 breaths/min.
What is the appropriate I:E ratio for TTJV?
1:3 or 1:4.
What are some risks associated with TTJV?
- Barotrauma
- Subcutaneous emphysema
- Pneumothorax
- Catheter obstruction
What pressures should be used for TTJV to improve safety?
Lower inspiratory pressures (25-50 psi) and ensuring a patent upper airway.
