BREATHING CIRICUIT Flashcards
What is the function of the Oxygen Analyzer?
To check the gas mixture before it reaches the patient.
How does a Galvanic Fuel Cell operate?
It operates based on a chemical reaction that generates an electrical current proportional to oxygen concentration.
What are the advantages of a Galvanic Fuel Cell?
- Long Life: Up to 2 years
- Self-Powered: Generates its own current.
What are the disadvantages of a Galvanic Fuel Cell?
- Slow Response
- Requires regular calibration.
What principle does a Paramagnetic Device operate on?
It uses a magnetic field to detect oxygen, as oxygen is a paramagnetic gas.
What are the advantages of a Paramagnetic Device?
- Rapid Response
- High Accuracy.
What are the disadvantages of a Paramagnetic Device?
- Higher cost
- Requires external power.
What is an open anesthesia circuit?
A simple anesthesia delivery system with no rebreathing components.
What are the basic components of an open circuit?
- Source of fresh gas
- Delivery system (mask, nasal prongs)
- Unidirectional flow path.
What are the situations where open circuits are used?
- Short, minor procedures
- Emergency situations.
What are the advantages of open circuits?
- Simplicity
- 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 loss of consciousness.
What occurs during Stage II of anesthesia?
Involuntary movements, irregular breathing, heightened reflexes.
What is the goal during Stage II of anesthesia?
To pass through this stage quickly to minimize risks and discomfort.
What defines Stage III of anesthesia?
Further divided into four planes, diminishing reflexes, increasing muscle relaxation.
What is Stage IV of anesthesia characterized by?
Severe CNS depression, cessation of spontaneous respiration, potential circulatory collapse.
What are Mapleson Circuits?
Semi-open breathing systems used for inhalation anesthesia.
What is the principle of operation for Mapleson Circuits?
Fresh Gas Flow (FGF) flushes out exhaled gases to prevent rebreathing.
What is the function of the reservoir bag in Mapleson Circuits?
To monitor the patient’s breathing and assist in manual ventilation.
What is Mapleson A (Magill’s Circuit) used for?
Mainly for spontaneous ventilation.
What is a key feature of Mapleson D (Bain Circuit)?
Coaxial design with fresh gas flow tube inside the expiratory limb.
What is the Pethick Test used for?
To check the proper functioning of the Bain circuit.
What should happen to the reservoir bag during the Pethick Test when the patient end is occluded?
The reservoir bag should inflate and remain inflated.
What is Fresh Gas Coupling (FGC)?
A mechanism where fresh gas flow influences the volume of gas delivered to the patient.
How does Fresh Gas Coupling affect tidal volume?
It increases the volume of gas delivered by adding fresh gas flow to the set tidal volume.
What are the clinical implications of Fresh Gas Coupling?
- Anesthetic Depth
- Volume Control
- Machine Differences.
What is required for calculating the actual tidal volume in Fresh Gas Coupling?
Actual Tidal Volume = Set Tidal Volume + FGC Effect.
What is the formula to estimate the actual tidal volume delivered to a patient?
Actual Tidal Volume = Set Tidal Volume + FGC Effect
Where FGC Effect is the additional volume contributed by the fresh gas flow.
What factors are considered when calculating the FGC Effect?
- Fresh Gas Flow Rate (FGF)
- Duration of Inspiration
FGC Effect is calculated as FGC Effect = FGF x Duration of Inspiration.
Define tidal volume in the context of mechanical ventilation.
Tidal volume is the volume of air delivered to the lungs with each breath during mechanical ventilation.
How does fresh gas flow (FGF) impact tidal volume?
An increase in FGF can artificially inflate the tidal volume.
What is the I:E ratio?
The I:E ratio is the ratio of time spent in inspiration versus expiration during mechanical ventilation.
How does FGF affect the I:E ratio?
If FGF increases tidal volume significantly, it might require adjustments in ventilatory settings, including potentially altering the I:E ratio.
What is respiratory rate in the context of mechanical ventilation?
Respiratory rate is the number of breaths delivered to the patient per minute by the ventilator.
Does fresh gas flow directly change the set respiratory rate?
No, FGF doesn’t directly change the set respiratory rate.
What is the filling mechanism of ascending bellows?
Ascending bellows are filled from the bottom.
What is a safety feature of ascending bellows?
Leak detection occurs when the bellows fail to ascend or ascend less than expected.
How do descending bellows fill?
Descending bellows are filled from the top.
What is a safety concern with descending bellows?
A leak may not be immediately apparent, as the bellows can still descend due to gravity.
What is the primary mechanism of piston ventilators?
Piston ventilators use an electric motor to drive a piston within a cylinder.
What are the advantages of piston ventilators?
- Precision in tidal volume delivery
- Independence from driving gas
- Equipped with feedback mechanisms
Feedback systems adjust based on the patient’s lung compliance and resistance.
List 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.
Define spontaneous breathing.
Spontaneous breathing refers to the patient’s own respiratory effort without any assistance from a mechanical ventilator.
What characterizes assisted breathing?
The patient initiates the breath, and the ventilator provides additional volume or pressure.
What is controlled breathing?
Controlled breathing is when the ventilator completely takes over the work of breathing for the patient.
What are the clinical applications of Controlled Mandatory Ventilation (CMV)?
- Deep anesthesia
- Respiratory failure
- Neuromuscular disorders.
What are considerations when using CMV?
- Risk of hypoventilation or hyperventilation
- Lung protection
- Patient sedation.
What is the purpose of Assist Control Ventilation (ACV)?
Used for patients who can breathe spontaneously but need assistance to maintain adequate ventilation.
What are the risks associated with ACV?
- Risk of hyperventilation
- Patient comfort
- Adjustment of sensitivity.
What is Synchronized Intermittent Mandatory Ventilation (SIMV) used for?
Often used in the weaning process, allowing patients to gradually take over more of the breathing work.
What are the clinical applications of Pressure Control Ventilation - Volume Guaranteed (PCV-VG)?
- Lung protective ventilation
- Variable respiratory conditions.
What are considerations when using PCV-VG?
- Monitoring and adjustments
- Balance of pressure and volume
- Patient comfort and synchrony.
What is Pressure Support Ventilation (PSV) primarily used for?
Commonly used in the weaning process, allowing patients to gradually take on more of the work of breathing.
What are the considerations for PSV?
- Risk of hypoventilation
- Patient-ventilator synchronization
- Adjusting pressure support.
What is Continuous Positive Airway Pressure (CPAP) used for?
- Prevention of airway collapse
- Lung expansion therapy
- Weaning and post-extubation.
What is required for CPAP to be suitable for a patient?
Adequate spontaneous breathing is required.
What is Continuous Positive Airway Pressure (CPAP) used for?
Commonly used in conditions like obstructive sleep apnea (OSA), lung expansion therapy, and post-extubation support.
CPAP helps prevent airway collapse and atelectasis.
What is a key consideration when using CPAP?
Adequate spontaneous breathing is required for effectiveness.
CPAP is suitable only for patients who can maintain their own respiratory effort.
What are the risks associated with CPAP?
Risk of barotrauma and patient comfort issues.
Monitoring is necessary to prevent complications.
How does the transition from CPAP occur?
Based on the patient’s ability to maintain ventilation and airway patency without continuous positive pressure.
Adjustment is made according to the patient’s condition.
What is Bilevel Positive Airway Pressure (BiPAP) primarily used for?
Respiratory insufficiency, reduction of respiratory workload, and nocturnal ventilation support.
BiPAP is beneficial for patients who can breathe spontaneously.
What is a critical consideration when using BiPAP?
Patient comfort and risk of asynchrony between patient and ventilator.
Monitoring is crucial to ensure effective settings.
What defines the transition from BiPAP?
Adjustment based on improvement of the patient’s respiratory status.
Levels of support can be reduced as the patient’s condition improves.
What is Airway Pressure Release Ventilation (APRV) used for?
Lung protective strategy, reduced sedation needs, and improved oxygenation.
Particularly beneficial in managing ARDS.
What must be monitored when using APRV?
Monitoring and adjustment are required to optimize oxygenation and ventilation.
Careful assessment helps mitigate risks.
What are the risks associated with APRV?
Risk of hypoventilation and hemodynamic impact due to sustained high intrathoracic pressure.
Requires careful cardiovascular monitoring.
How does the transition from APRV occur?
Gradual adjustment of P-high and time settings as the patient’s lung function improves.
This helps in reducing respiratory support gradually.
What is the primary application of Inverse Ratio Ventilation (IRV)?
Used in refractory hypoxemia and lung recruitment.
Effective for conditions like ARDS.
What are the risks of using IRV?
Risk of lung injury and hemodynamic compromise.
Increased airway pressure can lead to complications.
What is required during the transition from IRV?
Gradual reduction of inspiratory time to return to a conventional I:E ratio.
This is done as the patient’s lung function improves.
What is High Frequency Ventilation (HFV) used for?
Lung protection, pediatric and neonatal care, and airway surgery.
Particularly useful when conventional ventilation is not optimal.
What considerations are important when using HFV?
Monitoring ventilation and oxygenation, hemodynamic impact, and specialized equipment requirements.
HFV necessitates specific ventilators and expertise.
How does the transition from HFV occur?
Gradual transition to conventional ventilation as the patient’s condition improves.
This should consider the patient’s lung mechanics.
What principle does Jet Ventilation utilize?
The Venturi effect, which allows entrainment of additional gas or fluid into the main flow.
This principle enhances ventilation volumes.
What are Airway Exchange Catheters (AECs) used for?
Facilitate changing or removing endotracheal tubes and can deliver jet ventilation.
AECs must be placed properly to avoid trauma.
What is Needle Cricothyrotomy with Transtracheal Jet Ventilation (TTJV)?
An emergency technique for ‘cannot intubate, cannot oxygenate’ scenarios.
Involves using a large-bore catheter for ventilation.
What is the typical respiratory rate for TTJV?
~8-10 breaths/min with an appropriate I:E ratio of 1:3 or 1:4.
This helps prevent air trapping.
What are the risks associated with TTJV?
Barotrauma, subcutaneous emphysema, pneumothorax, and catheter obstruction.
Lower inspiratory pressures improve safety.
