p.22
Safety Features of Anaesthetic Machines
What occurs during expiration with the Ambu e valve?
The inspiratory port leaf valve seals while the expiratory port leaf valve opens, allowing exhaled gases to escape.
p.21
Invasive Cardiac Output Measurement Techniques
What is the function of the Reuben valve during positive pressure ventilation?
It closes the expiratory port, allowing fresh gas to enter the patient.
p.14
Safety Features of Anaesthetic Machines
What is the immediate consequence of a disconnection in the breathing circuit if identified rapidly?
There should be no significant consequences.
p.2
Pulmonary Artery Flotation Catheter (PAFC)
What is the length and design of the PAFC?
110 cm long, balloon-tipped, flow-directed catheter.
p.12
Safety Features of Anaesthetic Machines
What do the color codes on vaporisers indicate?
Blue for desflurane, yellow for sevoflurane, and purple for isoflurane.
p.7
Depth of Anaesthesia Monitoring
What did NICE recommend in 2012 regarding DOA monitoring?
The use of EEG-based DOA monitoring (BIS, E-Entropy, or Narcotrend-Compact M) for patients at higher risk of awareness or excessive DOA.
p.12
Safety Features of Anaesthetic Machines
What feature do modern vaporisers have to prevent spills?
A non-spill reservoir allowing up to 180° of tilt.
p.1
Fick's Principle for Cardiac Output Calculation
How is cardiac output (CO) calculated using Fick's principle?
CO = V̇O2 / (CaO2 - CvO2), where V̇O2 is oxygen uptake, CaO2 is arterial oxygen content, and CvO2 is mixed venous oxygen content.
p.9
Depth of Anaesthesia Monitoring
What was the outcome of the b-unaware and bag-recall trials regarding awareness risk?
Both trials found no difference in the risk of awareness between bis-guided anaesthesia and protocol with alarms.
p.7
Depth of Anaesthesia Monitoring
What pattern of EEG changes is produced by propofol, thiopentone, and volatile anaesthetic agents?
Increasing high-frequency EEG components, low-frequency EEG components, waveform amplitude, regularity of EEG signal, burst suppression, and isoelectric flat line with deep anaesthesia.
What is the purpose of the pressure release valve in the Mapleson A system?
To vent gas and prevent rebreathing.
p.2
Pulmonary Artery Flotation Catheter (PAFC)
What is a pulmonary artery flotation catheter (PAFC)?
A device used to measure cardiac filling pressures, pulmonary artery occlusion pressure, central venous oxygen saturations, and core temperature.
p.14
Safety Features of Anaesthetic Machines
What occurs to a ventilated patient after a disconnection?
The patient remains apnoeic and oxygen saturations fall.
What occurs if the fresh gas flow is too low?
The bag will not be filled solely by dead space gas, allowing some alveolar gas to enter the bag, leading to rebreathing.
p.14
Safety Features of Anaesthetic Machines
How is a disconnection incident classified based on its outcome?
It could be classified as a critical incident or a serious incident requiring investigation.
p.11
Safety Features of Anaesthetic Machines
What are the colour codes for oxygen, nitrous oxide, and air gas cylinders?
Oxygen = black body with white shoulder, Nitrous oxide = blue body with blue shoulder, Air = black body with white and black shoulders.
p.2
Pulmonary Artery Flotation Catheter (PAFC)
What is the purpose of the balloon at the tip of the PAFC?
To allow the catheter to advance with blood flow and to enable measurement of pulmonary capillary wedge pressure.
p.13
Safety Features of Anaesthetic Machines
Where can disconnections in the breathing circuit occur?
Between the catheter mount and airway device, HME filter and catheter mount, breathing circuit and HME filter, anaesthetic machine and breathing circuit.
p.2
Thermodilution Technique for Cardiac Output Measurement
How is cardiac output measured using the thermodilution technique?
By injecting ice-cold saline into the right atrium and measuring the temperature change over time.
What are the three phases of the respiratory cycle?
Inspiration, expiration, and the expiratory pause.
p.16
Non-Invasive Cardiac Output Measurement Techniques
What is the initial statement when describing breathing systems?
The patient has just exhaled, the equipment is full of fresh gas and I put the mask over the patient’s face.
p.9
Depth of Anaesthesia Monitoring
In what other settings might a BIS monitor be used?
In intensive care units to monitor burst suppression in patients with head injuries, raised intracranial pressures, or status epilepticus.
p.13
Safety Features of Anaesthetic Machines
What is the most important monitor for detecting disconnection in the breathing circuit?
The vigilant anaesthetist.
p.13
Safety Features of Anaesthetic Machines
What factors must be considered to determine which monitors would alarm during a disconnection?
The location of the disconnection, whether the patient is breathing spontaneously or being ventilated, and the alarm parameters set.
What classification system is commonly used for breathing systems?
The Mapleson classification system.
p.5
Non-Invasive Cardiac Output Measurement Techniques
How does the nICO measure changes in CO2 concentration?
By using intermittent periods of partial rebreathing through a special rebreathing loop.
p.13
Safety Features of Anaesthetic Machines
What occurs if a ventilated patient experiences a disconnection in the breathing circuit?
EtCO2 measurement and trace would be lost, tidal volumes and minute ventilation would fall, and airway pressures would drop, triggering alarms.
p.6
Thermodilution Technique for Cardiac Output Measurement
What volumetric markers of preload does the PiCCO device measure?
Global end-diastolic volume, intrathoracic blood volume, and extravascular lung water.
p.1
Dye or Indicator Dilution Technique
How is the dye or indicator dilution technique used to measure cardiac output?
A known quantity of dye or indicator is injected into a central vein and measured distally from a peripheral arterial blood sample.
p.12
Safety Features of Anaesthetic Machines
What risk is associated with the use of the oxygen flush?
Risk of barotrauma and anaesthetic agent dilution.
p.16
Non-Invasive Cardiac Output Measurement Techniques
What contributes to filling the reservoir bag during exhalation?
The fresh gas flow will also contribute to filling the bag.
p.6
Thermodilution Technique for Cardiac Output Measurement
In what condition is LiDCO calibration not possible?
In the presence of atracurium.
p.22
Safety Features of Anaesthetic Machines
What happens during positive pressure ventilation with the Ambu e valve?
The inspiratory port leaf valve seals the expiratory port, allowing gases to enter the patient.
p.22
Safety Features of Anaesthetic Machines
What issue can arise during low inspiratory gas flow rates with the Ambu e valve?
The inspiratory port leaf valve may not seal well, allowing fresh gas to escape and reducing supply to the patient.
p.2
Pulmonary Artery Flotation Catheter (PAFC)
Where should the distal lumen of the PAFC be positioned?
In the pulmonary artery to measure PA pressure and sample mixed venous blood.
p.9
Depth of Anaesthesia Monitoring
What did the National Audit Project (NAP) 5 identify about end-tidal anaesthetic gas monitoring?
It is a reliable method for ensuring the desired concentration of inhalational agent is administered when used with audible alarms.
p.11
Safety Features of Anaesthetic Machines
How do gas cylinders connect to the anaesthetic machine?
Via a pin-indexed system incorporating a bodok seal for a gas-tight connection.
p.18
Non-Invasive Cardiac Output Measurement Techniques
What happens to the alveolar gas during exhalation in the Mapleson D system?
The alveolar gas is vented through the pressure release valve to avoid rebreathing.
p.23
Safety Features of Anaesthetic Machines
What is the purpose of the Ambu 'mushroom' valve?
To control the flow of air during expiration and inspiration.
p.7
Depth of Anaesthesia Monitoring
What is the purpose of Depth of Anaesthesia (DOA) monitoring?
To reduce the risk of accidental awareness during general anaesthesia and to titrate the dose of anaesthetic agent.
p.4
Pulmonary Capillary Wedge Pressure (PCWP) Interpretation
What conditions cause PCWP to underestimate left ventricular end-diastolic pressure (LVE DP)?
Conditions causing increased pressure within the left ventricle that the catheter tip cannot detect, such as poorly compliant left ventricle and LVE DP > 25 mmHg.
p.4
Pulmonary Capillary Wedge Pressure (PCWP) Interpretation
How is a PCWP of 25 mmHg interpreted?
It is commonly interpreted as hypervolemia with increased left ventricular end-diastolic volume (LVE DV), but can also indicate normal or reduced LVE DV in cases of increased juxtacardiac pressure or reduced ventricular compliance.
p.13
Safety Features of Anaesthetic Machines
What happens to EtCO2 trace if a spontaneously breathing patient has a disconnection proximal to the sampling point?
The EtCO2 trace would still be present, but the patient would not receive fresh gas flow.
p.21
Invasive Cardiac Output Measurement Techniques
What should be done to assist patients with respiratory fatigue using a resuscitation bag?
Gently squeeze the bag when they inspire to help open the valves and reduce resistance.
p.10
Safety Features of Anaesthetic Machines
What is essential to ensure patient safety before using an anaesthetic machine?
A pre-use check to ensure the correct functioning of the machine and equipment.
p.4
Non-Invasive Cardiac Output Measurement Techniques
How does the transcutaneous Doppler technique work?
It uses the Doppler effect to measure blood flow in the pulmonary artery and across the semi-lunar valves, with a probe placed on the supra-sternal notch.
What happens to alveolar gas after dead space gas is exhaled?
It is vented through the APL valve and lost from the system, avoiding rebreathing.
p.2
Thermodilution Technique for Cardiac Output Measurement
How is cardiac output data acquired using the PAFC?
Through thermodilution methods.
p.14
Safety Features of Anaesthetic Machines
What are the potential consequences of prolonged disconnection for a ventilated patient?
Hypoxia, ECG changes (most likely bradycardia), hypotension, and potentially cardiac arrest.
p.21
Invasive Cardiac Output Measurement Techniques
How does the Reuben valve self-inflate?
It draws in air from the room and oxygen from the reservoir bag.
p.21
Invasive Cardiac Output Measurement Techniques
What risk is associated with a jammed Reuben valve?
It can keep the inspiratory port continuously open, risking hyperinflation of the lungs.
p.6
Thermodilution Technique for Cardiac Output Measurement
How is the PiCCO device calibrated?
Via a transpulmonary thermodilution technique.
p.12
Safety Features of Anaesthetic Machines
What is the purpose of back-bar pressure relief valves?
To vent off gas mixtures at pressures greater than 35 kPa, preventing barotrauma to flow meters and vaporisers.
p.16
Non-Invasive Cardiac Output Measurement Techniques
What is the Mapleson A system also known as?
The non-co-axial ‘Magill’ system.
p.2
Pulmonary Capillary Wedge Pressure (PCWP) Interpretation
What does pulmonary capillary wedge pressure (PCWP) indicate?
Left atrial filling pressure and left ventricular end-diastolic pressure (LVEDP).
p.19
Non-Invasive Cardiac Output Measurement Techniques
What fresh gas flow is required to prevent rebreathing in both Mapleson E and F systems?
Fresh gas flows of 2.5 × MV.
p.18
Non-Invasive Cardiac Output Measurement Techniques
What is a consequence of over-ventilating patients in the Bain circuit?
The end-tidal CO2 will not rise despite the patient rebreathing.
p.6
Thermodilution Technique for Cardiac Output Measurement
How does the LiDCO device track changes in stroke volume?
By tracking the power of the arterial waveform rather than its contour.
p.3
Invasive Cardiac Output Measurement Techniques
What equation is used to calculate cardiac output?
The Stewart–Hamilton equation: q = v (TB – T1)K1 K2 TB(t)dt.
p.14
Safety Features of Anaesthetic Machines
What happens to a spontaneously breathing patient if a disconnection is not identified quickly?
The patient would continue to breathe room air and may wake up.
p.9
Depth of Anaesthesia Monitoring
What is the purpose of the balloon catheter in lower oesophageal contractility monitoring?
To trigger and record oesophageal contractions for generating the oesophageal contractility index.
p.18
Non-Invasive Cardiac Output Measurement Techniques
How does the patient inhale fresh gas in the Mapleson D system?
The patient inhales fresh gas from the supply and from the deflating reservoir bag.
p.21
Invasive Cardiac Output Measurement Techniques
What resistance do the valves offer during inspiration and expiration?
0.8 cm H2O during inspiration and 1 cm H2O during expiration.
What is the efficiency of the Mapleson A system for spontaneous ventilation?
Efficient at 70 ml/kg/min.
p.10
Safety Features of Anaesthetic Machines
What is one of the principal functions of the anaesthetic machine?
To receive compressed gases from their supplies (pipeline or cylinder).
p.11
Safety Features of Anaesthetic Machines
What do pressure regulators do in anaesthetic machines?
They reduce the pressure of cylinder gases to approximately 400 kPa to protect the machine from high gas pressures.
p.20
Non-Invasive Cardiac Output Measurement Techniques
What type of resuscitation bag is found on a cardiac arrest trolley?
A self-inflating bag with a non-rebreathing valve and mask.
p.7
Depth of Anaesthesia Monitoring
What does the BIS monitor measure?
It produces a dimensionless number between 0 and 100 to measure the depth of anaesthesia.
What is the purpose of reservoir bags in breathing systems?
To allow the patient to draw oxygen and gases during deep inspiration.
p.13
Depth of Anaesthesia Monitoring
What monitors are essential for the induction and maintenance of general anaesthesia?
Trained anaesthetist, anaesthetic machine, airway equipment, emergency drugs, ECG, blood pressure, oxygen saturations, FiO2, EtCO2 with capnography, ventilating volumes, airway pressures, temperature monitoring, and depth of anaesthesia monitoring.
p.11
Safety Features of Anaesthetic Machines
What is the purpose of colour-coded gas cylinders in anaesthetic machines?
They act as an emergency source of gases if primary piped gas delivery fails.
p.4
Pulmonary Capillary Wedge Pressure (PCWP) Interpretation
In what conditions does PCWP overestimate left ventricular end-diastolic pressure (LVE DP)?
Conditions creating an interfering pressure gradient, such as mitral stenosis, positive end-expiratory pressure (PEEP), and pulmonary hypertension.
p.7
Depth of Anaesthesia Monitoring
How do EEG-based DOA monitors work?
They use electrodes on the forehead to measure EEG activity, which is processed using proprietary algorithms.
p.19
Non-Invasive Cardiac Output Measurement Techniques
What is the purpose of the open-ended reservoir bag in the Mapleson F system?
It allows for the application of CPAP and controlled ventilation.
p.6
Thermodilution Technique for Cardiac Output Measurement
What does the PiCCO device identify to determine stroke volume (SV)?
The area under the curve (AUC) by recognizing the dicrotic notch on the arterial waveform.
p.1
Assumed Fick Determination
What is meant by 'assumed Fick determination'?
Using an assumed value for oxygen consumption (250 ml/min or 125 ml/min/m²) to calculate cardiac output due to the cumbersome nature of direct measurements.
p.11
Safety Features of Anaesthetic Machines
What are the two types of flowmeters used in anaesthetic machines?
Mechanical (rotameters) and electronic flowmeters.
p.20
Non-Invasive Cardiac Output Measurement Techniques
What is the purpose of the non-rebreathing valve in a self-inflating bag?
To ensure gas flows out of the bag into the patient during inspiration and prevents exhaled gases from re-entering the bag.
p.10
Safety Features of Anaesthetic Machines
What is the purpose of non-interchangeable screw threads in anaesthetic machines?
To ensure gas-specific connections that are permanently fixed.
p.3
Pulmonary Capillary Wedge Pressure (PCWP) Interpretation
What does PCWP stand for and what are its pressure values?
Pulmonary Capillary Wedge Pressure (PCWP) values are 4–12 mmHg.
p.23
Safety Features of Anaesthetic Machines
What happens to the Ambu valve during expiration?
It closes to prevent atmospheric air from entering.
p.22
Safety Features of Anaesthetic Machines
Why should the Ambu e valve be used cautiously in spontaneously ventilating patients?
Because it offers resistance.
p.23
Safety Features of Anaesthetic Machines
What is FiO2?
Fraction of inspired oxygen.
p.21
Invasive Cardiac Output Measurement Techniques
What happens to the Reuben valve during expiration?
The bobbin shifts to close the inspiratory port, allowing exhaled gases to escape.
p.9
Depth of Anaesthesia Monitoring
Who originally described the isolated forearm technique?
Tunstall, an obstetric anaesthetist, in 1977.
p.19
Non-Invasive Cardiac Output Measurement Techniques
What are the characteristics of the Mapleson E system?
It has no valves or reservoir bag, making it a very low resistance system.
p.19
Non-Invasive Cardiac Output Measurement Techniques
Why is the Mapleson E system suitable for use in pediatrics?
Due to its low resistance.
p.19
Non-Invasive Cardiac Output Measurement Techniques
What modification does the Mapleson F system have?
It includes an open-ended reservoir bag connected to the end of the tubing.
p.18
Non-Invasive Cardiac Output Measurement Techniques
What is the efficiency of the Mapleson D system for controlled ventilation?
It is efficient for controlled ventilation at a flow rate of 70 ml/kg/min.
p.2
Thermodilution Technique for Cardiac Output Measurement
What fluid is typically used in the thermodilution technique?
10 ml ice-cold 0.9% saline or 5% dextrose.
p.8
Depth of Anaesthesia Monitoring
What is the significance of the 40-60 range in the context of surgical anaesthesia?
It indicates surgical anaesthesia where auditory processing is possible but memory recall is less likely.
What is the colloquial name for the Mapleson C system?
Waters' circuit, although this is technically inaccurate.
p.1
Dye or Indicator Dilution Technique
What is a 'recirculation hump' in the context of dye dilution technique?
A second peak seen on the concentration-time curves due to the recirculation of the dye or indicator, which limits the number of measurements.
What type of gas is exhaled first during expiration?
Gas from the anatomical dead space, which does not contain CO2 and is not depleted of O2.
p.5
Invasive Cardiac Output Measurement Techniques
What is the significance of the Doppler shift in the transoesophageal Doppler technique?
It correlates directly with the speed of blood traveling in the aorta.
What features do modern monitors have for alarms?
Prioritised preset alarms with audible and visual components, which can be individualised.
p.8
Depth of Anaesthesia Monitoring
What does Power Spectral Analysis (PSA) analyze?
It analyzes raw EEG data by breaking it down into constituent sine waves.
p.6
Invasive Cardiac Output Measurement Techniques
Are PiCCO and LiDCO devices reliable with arrhythmias?
No, both are not reliable with arrhythmias.
p.23
Safety Features of Anaesthetic Machines
What factors determine the oxygen concentration delivered to the patient?
FiO2, oxygen flow rate, reservoir bag volume, inspiratory flow rate, respiratory rate, and valve type.
What is the consequence of high fresh gas flow?
It fills the bag and vents dead space gas along with alveolar gas, which avoids rebreathing but is wasteful and inefficient.
What are the three main objectives of using a breathing system?
To supply O2 to the patient, to allow removal of CO2 from the system and avoid rebreathing, and to supply anaesthetic gases to the patient.
p.12
Safety Features of Anaesthetic Machines
How is the oxygen failure warning device activated?
When the oxygen supply pressure falls below 2 bar.
p.10
Safety Features of Anaesthetic Machines
What is a key safety feature of an anaesthetic machine?
The presence of a trained, competent anaesthetist.
p.18
Non-Invasive Cardiac Output Measurement Techniques
In the co-axial Mapleson D system, how does fresh gas flow?
Fresh gas flows down the inner tubing while exhaled gas enters the outer tubing.
p.5
Non-Invasive Cardiac Output Measurement Techniques
What parameters are measured by sensors in the nICO system?
CO2, air flow, and airway pressures.
What distinguishes Mapleson B and C systems?
Mapleson C has shorter tubing compared to Mapleson B.
p.16
Non-Invasive Cardiac Output Measurement Techniques
What occurs when the patient exhales?
The dead space volume is expelled into the breathing system, passing down the tubing and fills the reservoir bag again.
p.18
Non-Invasive Cardiac Output Measurement Techniques
What flow rate is necessary to avoid rebreathing during controlled ventilation in the Bain circuit?
2.5 × mV, the same as for spontaneous ventilation.
p.20
Non-Invasive Cardiac Output Measurement Techniques
What components make up a non-rebreathing valve?
Inspiratory port, expiratory port, patient port, and one-way valve.
p.8
Depth of Anaesthesia Monitoring
What do high entropy values indicate?
They may indicate that the patient is awake or aware.
p.8
Depth of Anaesthesia Monitoring
What is the purpose of Auditory-evoked potentials (AEP) monitoring?
To assess the patient's awareness during anaesthesia based on auditory responses.
p.9
Depth of Anaesthesia Monitoring
What is the isolated forearm technique?
A method where a tourniquet is applied to the arm to prevent a neuromuscular blocking drug from reaching the muscles of the arm, preserving hand movement.
p.7
Depth of Anaesthesia Monitoring
What are some adverse effects of excessively deep anaesthesia?
Hypotension, impaired cardiac function, increased nausea and vomiting, and delayed recovery.
What does the anaesthetist do during controlled ventilation?
Squeezes the bag to force gas into the patient.
p.21
Invasive Cardiac Output Measurement Techniques
Why should resuscitation bags and valves be used cautiously in patients with respiratory fatigue?
They can significantly increase the work of breathing and impair passive expiration.
p.12
Safety Features of Anaesthetic Machines
What sound level does the oxygen failure alarm produce?
At least 60 dB for a minimum of 7 seconds.
p.16
Non-Invasive Cardiac Output Measurement Techniques
What happens when the patient inhales fresh gas?
The patient inhales fresh gas from the supply and from the reservoir bag, which deflates proportionally.
p.9
Depth of Anaesthesia Monitoring
How can BIS monitoring help in patients who are paralyzed for a long time?
It can be used to reduce awareness in those patients.
p.2
Pulmonary Artery Flotation Catheter (PAFC)
Why is the global use of the PAFC falling?
Due to newer, relatively less invasive methods of cardiac output monitoring becoming available.
p.4
Non-Invasive Cardiac Output Measurement Techniques
What principle does transthoracic electrical bioimpedance rely on?
It relies on changes in electrical impedance of the thoracic cavity during blood ejection from the heart, which reflects cardiac output.
p.6
Thermodilution Technique for Cardiac Output Measurement
What is a theoretical advantage of the LiDCO device?
Reduction of the effect of reflected waves.
p.5
Invasive Cardiac Output Measurement Techniques
What does the transoesophageal Doppler technique measure?
Velocity of blood flow in the descending thoracic aorta.
What types of measurements do modern anaesthetic machine monitors display?
Oxygen, inhalation agent, end-tidal carbon dioxide concentration, gas volume, and airway pressure.
p.5
Invasive Cardiac Output Measurement Techniques
What are the limitations of the transoesophageal Doppler technique?
Not tolerated by awake patients, operator dependent, and risk of oesophageal perforation.
p.18
Non-Invasive Cardiac Output Measurement Techniques
What is the main characteristic of the Mapleson D system for spontaneous ventilation?
It is inefficient for spontaneous ventilation at flow rates of < 2.5 × mV.
p.6
Thermodilution Technique for Cardiac Output Measurement
What technique does the LiDCO device use for calibration?
Lithium dilution technique.
p.9
Depth of Anaesthesia Monitoring
What are some limitations of EEG-based monitoring of depth of anaesthesia?
Heterogeneity and uncertainty due to individual responses, diverse case mixes, and variations in clinical practice.
p.4
Non-Invasive Cardiac Output Measurement Techniques
What are some non-invasive techniques for cardiac output measurement?
Transcutaneous Doppler and transthoracic electrical bioimpedance.
p.6
Thermodilution Technique for Cardiac Output Measurement
What dynamic indicators of volume responsiveness does the PiCCO device provide?
Stroke volume variation (SVV), pulse pressure variation (PPV), and systolic pressure variation (SPV).
p.8
Depth of Anaesthesia Monitoring
What happens to cerebrocortical activity with higher-frequency signals?
Cerebrocortical activity increases.
p.12
Safety Features of Anaesthetic Machines
What is the function of the oxygen flush?
Supplies 100% oxygen at rates between 35 and 75 l/min, bypassing flowmeters and vaporisers.
p.10
Safety Features of Anaesthetic Machines
What should be immediately available before commencing any anaesthetic?
A self-inflating bag, an alternative source of oxygen, relevant airway equipment, and emergency drugs.
p.19
Non-Invasive Cardiac Output Measurement Techniques
What is the minimum fresh gas flow for patients under 20 kg in the Mapleson E system?
2.5 × MV (minimum 3 L/min).
p.1
Dye or Indicator Dilution Technique
What is the purpose of plotting the concentration of dye over time in the dye dilution technique?
To analyze the concentration-time curve and calculate cardiac output based on the area under the curve (AUC).
p.4
Non-Invasive Cardiac Output Measurement Techniques
What are the limitations of transthoracic electrical bioimpedance?
Its reliability decreases in critically ill patients, and it has not gained wide clinical acceptance.
p.16
Non-Invasive Cardiac Output Measurement Techniques
What is the modification of the Mapleson F system?
Jackson-Rees modification.
What is the function of adjustable pressure-relieving (APL) valves in breathing systems?
To vent waste gases and overcome the problem of rebreathing.
p.8
Depth of Anaesthesia Monitoring
Why are indirect autonomic responses unreliable signs of consciousness?
Absence of sympathetic activity does not exclude awareness, and autonomic responses are uncommon in reported accidental awareness cases.
p.11
Safety Features of Anaesthetic Machines
What material are modern gas cylinders made of?
Molybdenum steel, which is lighter and stronger than carbon steel.
What is the main feature of the co-axial Mapleson A system?
It has an inner tube surrounded by an outer one, designed to reduce bulkiness.
p.1
Fick's Principle for Cardiac Output Calculation
What is the significance of the a-v oxygen content difference in Fick's principle?
It is measured to determine cardiac output in the pulmonary circulation.
p.7
Depth of Anaesthesia Monitoring
Why are ketamine, nitrous oxide, and xenon less useful for EEG-derived indices?
They do not produce the same pattern of EEG changes as other anaesthetic agents.
p.3
Invasive Cardiac Output Measurement Techniques
What is the relationship between cardiac output and AUC?
Cardiac output is inversely related to AUC.
p.11
Safety Features of Anaesthetic Machines
How do mechanical flowmeters ensure accurate gas flow measurement?
They are produced with anti-static material to prevent the bobbin from sticking.
p.16
Non-Invasive Cardiac Output Measurement Techniques
Which Mapleson system is used on ITU?
Mapleson C (Waters' circuit).
p.6
Thermodilution Technique for Cardiac Output Measurement
What dynamic indicators of preload does the LiDCO device provide?
Stroke volume variation (SVV), systolic pressure variation (SPV), and pulse pressure variation (PPV).
p.3
Pulmonary Artery Flotation Catheter (PAFC)
How is cardiac output calculated using the pulsed heating bursts?
By detecting temperature changes with a thermistor and applying the Stewart–Hamilton method.
p.11
Safety Features of Anaesthetic Machines
What is the function of flow control needle valves?
They govern the transition from high- to low-pressure systems, reducing pressure as gas enters the flowmeter block.
p.13
Safety Features of Anaesthetic Machines
What happens to the ventilator if there is a disconnection in the breathing circuit?
The ventilator would alarm as the bellows would not be able to fill.
p.8
Depth of Anaesthesia Monitoring
What does the b-aware trial published in 2004 compare?
It compares bis-guided anaesthesia with standard care in patients at increased risk of awareness.
p.10
Safety Features of Anaesthetic Machines
What type of battery is present in modern anaesthetic machines?
A back-up, rechargeable battery.
p.1
Dye or Indicator Dilution Technique
What computer algorithms are used in the dye dilution technique?
Modified Stewart–Hamilton equation to calculate cardiac output.
p.6
Invasive Cardiac Output Measurement Techniques
Can PiCCO and LiDCO devices be used in awake patients?
Yes, they can be used in awake patients.
p.5
Invasive Cardiac Output Measurement Techniques
What physiological changes are assumed to reflect changes in cardiac performance in arterial pulse contour analysis?
Changes in vessel wall diameter.
p.5
Non-Invasive Cardiac Output Measurement Techniques
How is VCO2 calculated in the nICO system?
From minute ventilation including its CO2 content.
p.10
Safety Features of Anaesthetic Machines
What do modern anaesthetic machines have to alert the anaesthetist of a power failure?
Visual and audible indicators.
p.12
Safety Features of Anaesthetic Machines
What does the adjustable pressure-limiting valve do?
Allows excess gas to escape when a preset pressure is exceeded, reducing barotrauma risk.
p.11
Safety Features of Anaesthetic Machines
What is the role of anti-hypoxic mixture devices?
They prevent the inadvertent delivery of a hypoxic-inspired gas mixture.
p.1
Dye or Indicator Dilution Technique
How is the area under the curve (AUC) related to cardiac output in the dye dilution technique?
Cardiac output is inversely related to the area under the curve (AUC).
p.20
Non-Invasive Cardiac Output Measurement Techniques
What color is the inspiratory port of a non-rebreathing valve?
Often coloured blue ('blue to bag').
p.5
Invasive Cardiac Output Measurement Techniques
What does arterial pulse contour analysis link to cardiac output?
Pulse pressure (PP) and area under the systolic portion of the waveform (AUC).
p.5
Invasive Cardiac Output Measurement Techniques
What is required for arterial pulse contour analysis?
Insertion of an arterial line.
p.4
Non-Invasive Cardiac Output Measurement Techniques
What are the advantages of transthoracic electrical bioimpedance?
It is quick to set up, easy to use, and useful for estimating trends in cardiac output.
p.8
Depth of Anaesthesia Monitoring
What do e-entropy monitors measure?
They measure the irregularity in spontaneous brain and facial muscular activity.
p.10
Safety Features of Anaesthetic Machines
How are gas supplies connected to the anaesthetic machine?
Using colour-coded, flexible hosepipes that connect via a Schrader valve.
p.8
Depth of Anaesthesia Monitoring
What is the target range for the re and se scales in e-entropy monitoring?
The target range is 40-60.
p.6
Invasive Cardiac Output Measurement Techniques
What type of monitoring do both PiCCO and LiDCO devices provide?
Continuous beat-to-beat monitoring.
p.12
Safety Features of Anaesthetic Machines
What is the standard connection size for the common gas outlet?
22 mm male outer diameter/15 mm female internal diameter.
p.11
Safety Features of Anaesthetic Machines
What do vaporizers do in anaesthetic machines?
They convert volatile liquid into vapour and add a controlled amount of volatile to the fresh gas flow.
p.20
Non-Invasive Cardiac Output Measurement Techniques
What color is the expiratory port of a non-rebreathing valve?
Often coloured yellow or gold ('gold for go').
p.5
Invasive Cardiac Output Measurement Techniques
What is required to calculate stroke volume in the transoesophageal Doppler technique?
The product of the cross-sectional area of the aorta and the stroke distance.
p.3
Pulmonary Artery Flotation Catheter (PAFC)
What is the role of the electric heating coil in modern PAFCs?
It heats up the blood in a semi-random manner to provide continuous cardiac output data.
p.10
Safety Features of Anaesthetic Machines
What does the black, white, and blue color coding represent in gas supplies?
Black = air, white = oxygen, blue = nitrous oxide.
p.3
Invasive Cardiac Output Measurement Techniques
What does the change in blood temperature over time indicate?
It is used to calculate cardiac output.
p.20
Non-Invasive Cardiac Output Measurement Techniques
What is the purpose of the entrainment valve in a self-inflating bag?
To allow entrainment of air if the oxygen supply does not meet respiratory demands.
p.8
Depth of Anaesthesia Monitoring
What does the P rst scoring system assess?
It provides an objective assessment of sympathetic stimulation.
