p.5
Temperature Measurement Techniques
What are the two main types of sensors used in infrared tympanic membrane thermometers?
Pyroelectric sensor and thermopile sensor.
p.5
Temperature Measurement Techniques
How does a pyroelectric sensor work?
It contains crystals that alter their polarization depending on temperature.
p.19
Blood Pressure Measurement Methods
What role do transducer crystals play in Doppler ultrasound?
They transmit and receive ultrasound waves.
p.21
Blood Pressure Measurement Methods
Why do elderly patients have a higher systolic pressure?
Due to reduced vascular compliance secondary to atherosclerosis.
p.4
Temperature Measurement Techniques
What is the accuracy of resistance thermometers?
Extremely accurate to within ± 0.0001 °C.
p.2
Temperature Measurement Techniques
What is the SI unit of temperature?
The standard international (SI) unit of temperature measurement is the kelvin (K).
p.9
Oxygen Measurement Methods
What are the methods for measuring oxygen concentration in a gas mixture?
Clark polarographic electrode, galvanic fuel cell, paramagnetic O2 analyser, mass spectrometer, photoacoustic spectroscope, Raman spectroscope, and chemical methods (e.g., Haldane apparatus).
p.6
Anaesthetic Gas Pollution and Scavenging
What gases can contaminate the atmosphere during anaesthesia delivery?
Anaesthetic gases such as nitrous oxide and volatile agents.
p.2
Temperature Measurement Techniques
What is heat?
Heat is a form of energy associated with the kinetic motion of molecules within a substance.
p.23
Blood Pressure Measurement Methods
What factors determine cardiac output?
Heart rate, rhythm, preload, contractility, and afterload.
p.15
Carbon Dioxide Measurement Techniques
What device is used to measure CO2 in solution?
The Severinghaus CO2 electrode.
p.15
Carbon Dioxide Measurement Techniques
What is the principle behind the Severinghaus CO2 electrode?
Measurement of [H+] based on the reaction of CO2 with water.
p.23
Blood Pressure Measurement Methods
What are the ideal characteristics of a cardiac output monitoring method?
Non-invasive, accurate, continuous, safe, easy to use, operator independent, rapid data acquisition, and cost-effective.
p.19
Blood Pressure Measurement Methods
How is the probe positioned for Doppler ultrasound?
Over the artery with a coupling medium (e.g., gel).
p.9
Oxygen Measurement Methods
What is the purpose of the oxygen permeable membrane in the Clark polarographic electrode?
To allow oxygen to diffuse to the electrodes for measurement.
p.7
Anaesthetic Gas Pollution and Scavenging
What are the two main techniques of anaesthesia mentioned?
Total intravenous anaesthesia and regional anaesthesia.
p.9
Oxygen Measurement Methods
What reaction generates electrons at the anode of the Clark polarographic electrode?
The reaction of Ag+ with Cl− ions from the KCl solution.
p.21
Blood Pressure Measurement Methods
How can left ventricular contractility be estimated?
From the gradient of the upstroke of the arterial waveform.
p.18
Blood Pressure Measurement Methods
What are the disadvantages of using the blood pressure measurement method?
Operator dependent, correct cuff size required, artifacts with arrhythmias and movement, tourniquet effect can cause nerve damage, underestimates hypertension and overestimates hypotension.
p.15
Carbon Dioxide Measurement Techniques
How is CO2 measured in anaesthetic practice?
Through arterial blood gas analysis and capnography.
p.11
Oxygen Measurement Methods
What type of gas is oxygen in relation to magnetic fields?
Oxygen (O2) is a paramagnetic gas, meaning it is attracted to magnetic fields due to unpaired electrons.
p.14
pH Measurement and Its Importance
How is the pH electrode calibrated?
Using two standard buffer solutions of known pH.
p.2
Temperature Measurement Techniques
How do liquid expansion thermometers work?
They are based on the volumetric expansion of a liquid with increasing temperature, causing the liquid to rise in a calibrated capillary tube.
p.8
Anaesthetic Gas Pollution and Scavenging
What is the purpose of the open-ended cylinder in the receiving system?
To collect gases while ensuring the patient's airway is not subjected to excess pressure.
p.20
Blood Pressure Measurement Methods
What is the purpose of the pressurized fluid bag in an arterial line setup?
To prevent clot formation within the cannula by maintaining pressure.
p.8
Anaesthetic Gas Pollution and Scavenging
How are gases in the reservoir vented?
Gases are vented to the exterior atmosphere via a disposal system, which can be an air pump or a fan.
p.6
Anaesthetic Gas Pollution and Scavenging
How does nitrous oxide affect vitamin B12?
It oxidises the cobalt atom in vitamin B12, rendering it non-functional.
p.12
Oxygen Measurement Methods
What is the main component of a Raman spectroscope?
A helium-neon laser as its radiation source.
p.17
Blood Pressure Measurement Methods
What is the Riva-Rocci method based on?
Palpation of the brachial or radial artery as the cuff is inflated.
p.16
Carbon Dioxide Measurement Techniques
What is capnometry?
The numerical reading of carbon dioxide concentration in respiratory gases.
p.2
Temperature Measurement Techniques
What does temperature refer to?
Temperature refers to the thermal state of a substance and reflects its potential for heat transfer.
p.23
Blood Pressure Measurement Methods
What is cardiac output (CO)?
The volume of blood ejected from the left ventricle per minute.
p.19
Blood Pressure Measurement Methods
What are the disadvantages of the method discussed?
Downward drift due to tissue fluid relocation, painful after 20–30 minutes, and ischaemia of digit.
p.19
Blood Pressure Measurement Methods
How does Doppler ultrasound measure blood pressure?
It is based on the principle of the Doppler shift.
p.21
Blood Pressure Measurement Methods
What primarily influences systolic blood pressure?
Stroke volume and compliance.
p.3
Temperature Measurement Techniques
What are the advantages of gas expansion thermometers?
Cheap, robust, and provides continuous measurements.
p.13
pH Measurement and Its Importance
What does a 1 unit change in pH represent?
A 10-fold change in [H+].
p.11
Oxygen Measurement Methods
What happens to gas mixtures in a mass spectrometer?
They are ionized by electrons, creating charged particles that are accelerated through a magnetic field.
p.13
pH Measurement and Its Importance
How is [H+] measured in arterial blood gas analysers?
Using potentiometric electrodes.
p.22
Blood Pressure Measurement Methods
What is the relationship between natural frequency and system compliance?
Inversely related to the square root of the system compliance.
p.22
Blood Pressure Measurement Methods
How does the length of tubing affect the natural frequency?
Inversely related to the square root of the length of tubing.
p.6
Anaesthetic Gas Pollution and Scavenging
What methods can reduce pollution in the theatre?
Air conditioning with rapid air change, circle system, low gas flows, avoiding nitrous oxide, scavenging systems, and monitoring pollution levels.
p.12
Oxygen Measurement Methods
What is the purpose of the Haldane apparatus?
To estimate the proportion of oxygen in expired gases.
p.2
Temperature Measurement Techniques
How is a change in temperature of 1 K related to Celsius?
A change in temperature of 1 K is equivalent to a change in temperature of 1 °C.
p.2
Temperature Measurement Techniques
What happens to the volume of a gas if the absolute temperature doubles?
The volume of a gas will double only if the absolute temperature doubles.
p.6
Anaesthetic Gas Pollution and Scavenging
What agency placed constraints on the maximum allowable concentration of anaesthetic gases?
The Health and Safety Executive Agency.
p.9
Oxygen Measurement Methods
What materials are used for the anode and cathode in the Clark polarographic electrode?
Silver/silver chloride (Ag/AgCl) for the anode and platinum (Pt) for the cathode.
p.7
Anaesthetic Gas Pollution and Scavenging
How should vaporisers be filled?
Carefully to ensure no spillage.
p.14
pH Measurement and Its Importance
What is an alternative method to measure pH?
Using a pH indicator that changes color at a particular pH value.
p.18
Blood Pressure Measurement Methods
What are the advantages of using the blood pressure measurement method?
Simple, no electricity required, doctor-patient contact.
p.11
Oxygen Measurement Methods
What are the drawbacks of using a mass spectrometer?
It is bulky and expensive.
p.12
Oxygen Measurement Methods
How does the Haldane apparatus measure oxygen?
By exposing gas to a solution of pyrogallol and measuring the volume of remaining gas.
p.8
Anaesthetic Gas Pollution and Scavenging
What is the role of the Health and Safety Executive agency?
To prevent death, injury, and ill health in Britain's workplaces.
p.8
Anaesthetic Gas Pollution and Scavenging
What are the maximum recommended levels of halothane exposure?
10 ppm based on an 8-hour time-weighted average.
p.19
Blood Pressure Measurement Methods
What are the advantages of the method discussed?
Continuous reading and accurate measurements.
p.4
Temperature Measurement Techniques
In what clinical application are thermistors commonly used?
In PACU catheters to measure core temperature.
p.5
Temperature Measurement Techniques
What is the primary use of infrared tympanic membrane thermometers?
Clinical measurement of core body temperature.
p.15
Carbon Dioxide Measurement Techniques
What must be maintained at 37 °C in the CO2 measurement system?
The temperature of the system.
p.15
Carbon Dioxide Measurement Techniques
What is required before using the CO2 electrode?
Calibration with gas of known CO2 concentration.
p.1
Saturated Vapor Pressure and Vaporizer Function
What is the effect of temperature on the saturated vapor pressure (S v P) in a vaporizer?
As the temperature drops, the S v P of the vapor also decreases.
p.22
Blood Pressure Measurement Methods
What is damping in the context of arterial pressure waveforms?
The tendency of an object to resist oscillating.
p.12
Oxygen Measurement Methods
What is used instead of pyrogallol in the Haldane apparatus to measure CO2?
Potassium hydroxide solution.
p.10
Oxygen Measurement Methods
How is the issue of falsely high O2 readings from halothane overcome?
By using a halothane-impermeable membrane.
p.5
Temperature Measurement Techniques
What principle do infrared tympanic membrane thermometers operate on?
All objects emit electromagnetic radiation, with wavelength dependent on temperature.
p.4
Temperature Measurement Techniques
What are the advantages of using thermistors?
Rapid response time (<0.2 s), very small, accurate, and cheap.
p.4
Temperature Measurement Techniques
What are the disadvantages of thermistors?
Hysteresis, ageing, variability within a batch, and a non-linear relationship that requires recalibration.
p.11
Oxygen Measurement Methods
How does the paramagnetic oxygen analyser measure oxygen concentration?
It measures the degree of rotation of glass spheres caused by the attraction of O2 to a magnetic field, using light beam deflection.
p.17
Blood Pressure Measurement Methods
What is essential for understanding blood pressure measurement?
A good basic understanding of the principles underlying BP measurement.
p.23
Blood Pressure Measurement Methods
What is the clinical gold standard for accuracy in CO monitoring?
Conventional thermodilution techniques using a pulmonary artery floatation catheter (PAFC).
p.19
Blood Pressure Measurement Methods
What happens to the frequency of ultrasound waves during systole and diastole?
There is a Doppler shift in frequency.
p.12
Oxygen Measurement Methods
What can be determined by measuring sound at different wavelengths in photoacoustic spectroscopy?
The components within a gas sample.
p.7
Anaesthetic Gas Pollution and Scavenging
What is essential for staff regarding anaesthetic gases?
Training and education to be aware of potential hazards.
p.11
Oxygen Measurement Methods
What is the response time of mass spectrometry for gas analysis?
Less than 0.1 seconds, allowing for continuous gas analysis.
p.23
Blood Pressure Measurement Methods
How can blood flow to an organ be calculated using Fick’s principle?
Using a suitable marker substance (e.g., dye, temperature, or O2).
p.11
Oxygen Measurement Methods
What is a limitation of mass spectrometry?
Water vapor can interfere with the apparatus.
p.8
Anaesthetic Gas Pollution and Scavenging
What can excessive negative pressure cause in the breathing system?
It can deflate the reservoir bag and lead to rebreathing.
p.17
Blood Pressure Measurement Methods
What does Phase I in the Korotkoff method indicate?
The tapping sound appears, representing systolic blood pressure.
p.16
Carbon Dioxide Measurement Techniques
How does an infrared analyser measure CO2?
By measuring the proportion of infrared radiation absorbed by the gas mixture.
p.17
Blood Pressure Measurement Methods
What is the significance of Phase V in the Korotkoff method?
It indicates diastolic blood pressure in the USA.
p.1
Boiling and Colligative Properties
Why can't you have a nice cup of tea at the summit of Mount Everest?
At 8848 m, the ambient pressure is only 30 kPa, so water boils at around 80 °C instead of 100 °C.
p.4
Temperature Measurement Techniques
What are the disadvantages of resistance thermometers?
Slow response time, bulky, and fragile.
p.14
pH Measurement and Its Importance
How is the pH electrode maintained for accurate measurement?
[H+] is held constant around the pH electrodes by the buffer solution.
p.3
Temperature Measurement Techniques
What principle do gas expansion thermometers operate on?
Based on the volumetric expansion of a gas with temperature and the associated pressure changes.
p.3
Temperature Measurement Techniques
What happens to the shape of the hollow tube in a gas expansion thermometer as temperature rises?
It changes from elliptical to circular to accommodate the expanded gas.
p.7
Anaesthetic Gas Pollution and Scavenging
What should be done with breathing circuits when not in use?
Capping them to prevent small leaks.
p.20
Blood Pressure Measurement Methods
What are the indications for direct arterial blood pressure measurement?
When non-invasive BP measurements are inaccurate, during extreme changes in blood pressure, when frequent arterial blood samples are required, and when using pulse-contour cardiac output monitoring.
p.14
pH Measurement and Its Importance
What happens to pH during delays in arterial blood gas analysis?
pH falls approximately 0.0006 units per minute.
p.12
Oxygen Measurement Methods
What is the Raman effect?
The scattering of a photon in a gas, resulting in a change in vibrational, rotational, or electronic energy of a molecule.
p.17
Blood Pressure Measurement Methods
What is the recommended coverage of the cuff for the manual occlusive method?
Two-thirds of the length of the limb or 20% greater than the diameter of the limb.
p.13
pH Measurement and Its Importance
What is the function of the reference electrode in a pH measurement system?
It completes the circuit between the sample and the electrode.
p.7
Anaesthetic Gas Pollution and Scavenging
What causes gas movement in passive scavenging?
Pressure generated by the patient during expiration.
p.20
Blood Pressure Measurement Methods
What is the function of the diaphragm in an arterial line?
Acts as an interface between the transducer and the fluid column.
p.20
Blood Pressure Measurement Methods
What components are included in an arterial line used to measure blood pressure?
Arterial cannula, tubing, three-way tap and flushing device, pressurized fluid bag, diaphragm, and transducer.
p.10
Oxygen Measurement Methods
What is the lifespan of the cathode in oxygen measurement?
Around 3 years, due to protein coating.
p.2
Temperature Measurement Techniques
What is the triple point of water?
The temperature at which water exists in all three phases, which is 273.16 K or 0.01 °C at a specific pressure.
p.14
pH Measurement and Its Importance
What does the potential difference across the pH electrode indicate?
It indicates the [H+] within the blood sample.
p.5
Temperature Measurement Techniques
What is the function of a thermopile sensor?
It consists of numerous thermocouples connected in series for continuous measurements.
p.11
Oxygen Measurement Methods
What principle do newer versions of the paramagnetic analyser use?
They use the null deflection principle, where a current opposes the movement of the spheres to measure O2 concentration.
p.17
Blood Pressure Measurement Methods
What are the two main types of blood pressure measurement?
Invasive continuous and non-invasive methods.
p.23
Blood Pressure Measurement Methods
What methods are available to measure cardiac output?
Fick’s principle, thermal/indicator dilution techniques, doppler ultrasound, electrical bioimpedance, arterial pulse pressure contour analysis.
p.21
Blood Pressure Measurement Methods
What does the dicrotic notch represent?
The nadir point occurring immediately after the aortic valve closes.
p.7
Anaesthetic Gas Pollution and Scavenging
How can scavenging of anaesthetic gases be classified?
Into active and passive systems.
p.8
Anaesthetic Gas Pollution and Scavenging
What are the risks associated with excessive positive pressure in the active scavenging system?
It may lead to barotrauma.
p.17
Blood Pressure Measurement Methods
What happens if the cuff is too small?
It will over-read the blood pressure.
p.3
Temperature Measurement Techniques
What are the advantages of thermocouples?
Rapid response time, accurate to within ±0.1 °C, and small.
p.18
Blood Pressure Measurement Methods
What happens at systolic blood pressure in a von Recklinghausen’s oscillotonometer?
There is a sudden increase in needle oscillations.
p.7
Anaesthetic Gas Pollution and Scavenging
What is the function of an active scavenging system?
Utilises an external power source to generate negative pressure.
p.18
Blood Pressure Measurement Methods
What happens at diastolic blood pressure in a von Recklinghausen’s oscillotonometer?
There is a sudden decrease in needle oscillations.
p.16
Carbon Dioxide Measurement Techniques
What is the purpose of a water vapour trap in CO2 measurement?
To prevent interference from water, which has high infrared absorbance.
p.18
Blood Pressure Measurement Methods
What does the Finapres aim to keep constant?
The volume of the finger, which represents the mean arterial pressure.
p.4
Temperature Measurement Techniques
What is the principle of a thermistor?
It is a semiconductor that displays a negative exponential relationship between electrical resistance and temperature.
p.23
Blood Pressure Measurement Methods
Why is circulation essential?
It is essential for organ perfusion and O2 delivery.
p.23
Blood Pressure Measurement Methods
What is the significance of cardiac output monitoring?
It measures parameters associated with central circulation and aids in haemodynamic assessment.
p.2
Temperature Measurement Techniques
What are the three methods to measure temperature?
Temperature measurement can be divided into non-electrical, electrical, and infrared-based methods.
p.8
Anaesthetic Gas Pollution and Scavenging
How are gases collected from the breathing circuit?
Gases are collected via wide-bore, 30 mm diameter transfer tubing to the receiving system.
p.3
Temperature Measurement Techniques
What is a disadvantage of gas expansion thermometers?
Poor accuracy and requires recalibration.
p.1
Hypoxia and Alveolar Gas Equation
How does the saturated vapor pressure (S v P) of water at altitude contribute to hypoxia?
At 5500 m, the atmospheric pressure is 50 kPa, and the S v P of water is 6.3 kPa, leading to a lower partial pressure of oxygen (P AMB O2) and consequently hypoxia.
p.6
Anaesthetic Gas Pollution and Scavenging
What is a fire hazard associated with nitrous oxide?
It sustains combustion in the presence of lasers or grease.
p.3
Temperature Measurement Techniques
What is a key advantage of chemical thermometers?
Fast response time (<30 s), disposable, and no risk of glass breakage.
p.7
Anaesthetic Gas Pollution and Scavenging
What is a characteristic of passive scavenging?
It requires no external power.
p.1
Boiling and Colligative Properties
What is boiling?
A liquid boils when its saturated vapor pressure equals the surrounding ambient pressure, forming bubbles of vapor.
p.10
Oxygen Measurement Methods
What is the cathode reaction in oxygen measurement?
O2 combines with electrons and water to generate hydroxyl (OH–) ions: O2 + 4e– + 2H2O → 4OH–.
p.10
Oxygen Measurement Methods
How does the amount of O2 available affect current flow?
The greater the amount of O2 available, the greater the rate of electron uptake at the cathode, leading to a greater flow of current.
p.10
Oxygen Measurement Methods
What can cause falsely high O2 readings?
Halothane may cause falsely high O2 readings.
p.10
Oxygen Measurement Methods
What is the response time of the galvanic fuel cell?
Approximately 30 seconds, making it unsuitable for breath-to-breath measurements.
p.4
Temperature Measurement Techniques
What is the principle behind resistance thermometers?
There is a linear relationship between temperature and electrical resistance of a wire, such that resistance increases predictably with temperature.
p.5
Temperature Measurement Techniques
Why do tympanic membrane thermometers measure core body temperature?
Because the tympanic membrane is close to the brain.
p.9
Oxygen Measurement Methods
What is the overall reaction at the anode of the Clark polarographic electrode?
4Ag + 4Cl− → 4AgCl + 4e−.
p.6
Anaesthetic Gas Pollution and Scavenging
What is mandatory to comply with the constraints on anaesthetic gases?
Scavenging of expired anaesthetic gases.
p.12
Oxygen Measurement Methods
What types of light can produce acoustic waves in photoacoustic spectroscopy?
Non-visible portions of the light spectrum, such as infrared and ultraviolet light.
p.11
Oxygen Measurement Methods
How does a mass spectrometer distinguish between compounds of identical molecular weight?
By identifying their breakdown products, such as distinguishing N2O from CO2 using their respective fragments.
p.17
Blood Pressure Measurement Methods
What is the manual occlusive cuff method also known as?
Riva-Rocci or Korotkoff method.
p.12
Oxygen Measurement Methods
What does Raman spectroscopy measure?
The type of molecules present and their concentrations in a gas sample.
p.3
Temperature Measurement Techniques
What is the Seebeck effect?
The phenomenon where a voltage is produced due to a temperature difference across two junctions in a thermocouple.
p.18
Blood Pressure Measurement Methods
How does a von Recklinghausen’s oscillotonometer work?
Uses two cuffs; an occluding cuff and a sensing cuff, with bellows attached to a needle to display pressure.
p.1
Boiling and Colligative Properties
What are colligative properties?
Properties of a solution that depend on the number of dissolved particles in a solvent, not on their identities.
p.1
Boiling and Colligative Properties
How does adding solute affect the freezing point of water?
1 mole of solute added to 1 kg of water reduces its freezing point by 1.86 °C.
p.1
Raoult’s Law and Its Implications
What is Raoult's law?
It states that the depression of the saturated vapor pressure of a solvent is proportional to the molar concentration of the solute present.
p.1
Boiling and Colligative Properties
What happens to water in space?
Water cannot boil in space; it simply evaporates due to very low ambient pressure.
p.16
Carbon Dioxide Measurement Techniques
What are derived parameters from an arterial blood gas analyser?
HCO3-, base excess, and O2 saturations.
p.12
Oxygen Measurement Methods
What is the principle behind photoacoustic spectroscopy?
It is based on the photoacoustic effect, which converts light into sound waves.
p.15
Carbon Dioxide Measurement Techniques
What reaction occurs when CO2 diffuses across the membrane in the Severinghaus electrode?
CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3–.
p.5
Temperature Measurement Techniques
What is a key advantage of infrared tympanic membrane thermometers?
They are non-invasive, accurate, and have a rapid response time (<5 seconds).
p.6
Anaesthetic Gas Pollution and Scavenging
What environmental damage is caused by nitrous oxide and volatile agents?
They damage the ozone layer and contribute to global warming.
p.3
Temperature Measurement Techniques
How does a bimetallic strip dial thermometer work?
It consists of a coil of two different metals that expand by different amounts, causing the coil to tighten and move a pointer.
p.1
Hypoxia and Alveolar Gas Equation
What is the alveolar gas equation used to calculate the partial pressure of oxygen?
P AMB O2 = F AMB O2 × Atmospheric pressure at altitude.
p.6
Anaesthetic Gas Pollution and Scavenging
What are the adverse effects of nitrous oxide on staff?
Bone marrow toxicity, peripheral neuropathy, teratogenicity, spontaneous miscarriage, and substance abuse.
p.1
Saturated Vapor Pressure and Vaporizer Function
What happens to the temperature within a vaporizer as vapor is used up?
The temperature drops due to the energy requirement for vaporization (latent heat of vaporization).
p.21
Blood Pressure Measurement Methods
What can pulse contour analysis determine?
Stroke volume and cardiac output.
p.16
Carbon Dioxide Measurement Techniques
What techniques are used to measure CO2 in a gas mixture?
Infrared spectrography, mass spectrography, Raman spectrography, photoacoustic analysers, and colorimetric devices.
p.3
Temperature Measurement Techniques
What is a disadvantage of thermocouples?
The voltage produced is very small and needs signal amplification, and the reference junction must be at a constant temperature.
p.18
Blood Pressure Measurement Methods
What happens at mean arterial pressure in a von Recklinghausen’s oscillotonometer?
There is maximal amplitude in needle oscillations.
p.10
Oxygen Measurement Methods
What limits the lifespan of the galvanic fuel cell?
The reagents are consumed, limiting lifespan to 6–12 months.
p.10
Oxygen Measurement Methods
What gas mixtures may damage the fuel cell?
Gas mixtures containing N2O may damage the fuel cell.
p.14
pH Measurement and Its Importance
What are some sources of error in pH measurement?
Calibration errors, drift of the measuring system, membrane damage, temperature effects, sampling errors, and over-heparinisation.
p.2
Temperature Measurement Techniques
What are the advantages and disadvantages of mercury thermometers?
Advantages: Cheap and easy to use. Disadvantages: Slow, can break, and mercury is hazardous.
p.21
Blood Pressure Measurement Methods
Why do neonates have a lower systolic pressure?
Because of a very compliant arterial tree.
p.23
Blood Pressure Measurement Methods
What does Fick’s principle state?
The uptake or release of a substance by an organ is the product of blood flow through that organ and the arteriovenous concentration difference of the substance.
p.3
Temperature Measurement Techniques
What is the principle behind thermocouples?
Consists of two different metals joined to form two junctions, producing a small voltage proportional to the temperature difference.
p.20
Blood Pressure Measurement Methods
What factors determine the shape of the arterial waveform?
Volume of blood ejected, speed of ejection, compliance of the arterial tree, and systemic vascular resistance.
p.8
Anaesthetic Gas Pollution and Scavenging
What does COSHH stand for?
Control of Substances Hazardous to Health.
p.21
Blood Pressure Measurement Methods
Why is natural frequency important for arterial transducers?
It should be significantly different from the frequency of the arterial pressure wave to avoid signal amplification.
p.18
Blood Pressure Measurement Methods
What principle does the Penaz technique (Finapres) operate on?
The force exerted on a body can be determined by measuring an opposing force that prevents physical disruption.
p.7
Anaesthetic Gas Pollution and Scavenging
What is a drawback of passive scavenging?
It is not as effective as active methods.
p.7
Anaesthetic Gas Pollution and Scavenging
What are the components of an active scavenging system?
Collecting system, transfer system, receiving system, disposal system.
p.22
Blood Pressure Measurement Methods
What are some complications associated with arterial lines?
Cannula disconnection, arterial thrombosis, ischaemia, infection, inadvertent drug administration.
p.22
Blood Pressure Measurement Methods
What should be checked to prevent ischaemia distal to the cannula?
Collateral circulation (e.g., Allen’s test).
p.10
Oxygen Measurement Methods
What is the galvanic fuel cell similar to?
It is similar in principle to the Clark polarographic electrode.
p.21
Blood Pressure Measurement Methods
What is the effect of transducer height on arterial pressure readings?
An error reading equivalent to 7.5 mmHg occurs for each 10 cm discrepancy in height.
p.17
Blood Pressure Measurement Methods
What is indicated by Phase IV in the Korotkoff method?
Diastolic blood pressure in the UK.
p.16
Carbon Dioxide Measurement Techniques
What materials are used for the sample and reference chamber windows in infrared analysers?
Crystal (silver bromide or sapphire) because glass absorbs infrared.
p.16
Carbon Dioxide Measurement Techniques
What is the role of diatomic gas molecules in infrared analysis?
They absorb infrared radiation at specific wavelengths.
p.18
Blood Pressure Measurement Methods
How does a 'DINAMAP' work?
It merges occluding and sensing functions into a single cuff, using a transducer and processor to display blood pressure readings.
p.8
Anaesthetic Gas Pollution and Scavenging
In which hospital areas may long-term exposure limits be difficult to achieve?
Post-anesthesia care units and pediatric theatres.
p.16
Carbon Dioxide Measurement Techniques
What information can capnography provide?
Confirmation of endotracheal intubation, detection of rebreathing, obstructive expiratory airflow, and more.
p.10
Oxygen Measurement Methods
What is the function of the membrane covering the cathode?
It helps reduce protein deposition but increases the response time of the electrode.
p.18
Blood Pressure Measurement Methods
How does the Finapres cuff measure blood pressure?
It uses an infrared plethysmograph to detect changes in finger volume, adjusting cuff pressure to maintain a constant infrared signal.
