MasterPass PHYSICS 4

A double-leaf valve.

The inspiratory port leaf valve seals while the expiratory port leaf valve opens, allowing exhaled gases to escape.

It closes the expiratory port, allowing fresh gas to enter the patient.

There should be no significant consequences.

110 cm long, balloon-tipped, flow-directed catheter.

Blue for desflurane, yellow for sevoflurane, and purple for isoflurane.

The use of EEG-based DOA monitoring (BIS, E-Entropy, or Narcotrend-Compact M) for patients at higher risk of awareness or excessive DOA.

A non-spill reservoir allowing up to 180° of tilt.

CO = V̇O2 / (CaO2 - CvO2), where V̇O2 is oxygen uptake, CaO2 is arterial oxygen content, and CvO2 is mixed venous oxygen content.

Both trials found no difference in the risk of awareness between bis-guided anaesthesia and protocol with alarms.

Oxygen uptake.

Increasing high-frequency EEG components, low-frequency EEG components, waveform amplitude, regularity of EEG signal, burst suppression, and isoelectric flat line with deep anaesthesia.

To vent gas and prevent rebreathing.

A device used to measure cardiac filling pressures, pulmonary artery occlusion pressure, central venous oxygen saturations, and core temperature.

The patient remains apnoeic and oxygen saturations fall.

The bag will not be filled solely by dead space gas, allowing some alveolar gas to enter the bag, leading to rebreathing.

It could be classified as a critical incident or a serious incident requiring investigation.

Oxygen = black body with white shoulder, Nitrous oxide = blue body with blue shoulder, Air = black body with white and black shoulders.

To allow the catheter to advance with blood flow and to enable measurement of pulmonary capillary wedge pressure.

Between the catheter mount and airway device, HME filter and catheter mount, breathing circuit and HME filter, anaesthetic machine and breathing circuit.

By injecting ice-cold saline into the right atrium and measuring the temperature change over time.

Inspiration, expiration, and the expiratory pause.

The patient has just exhaled, the equipment is full of fresh gas and I put the mask over the patient’s face.

In intensive care units to monitor burst suppression in patients with head injuries, raised intracranial pressures, or status epilepticus.

The vigilant anaesthetist.

The location of the disconnection, whether the patient is breathing spontaneously or being ventilated, and the alarm parameters set.

The Mapleson classification system.

By using intermittent periods of partial rebreathing through a special rebreathing loop.

EtCO2 measurement and trace would be lost, tidal volumes and minute ventilation would fall, and airway pressures would drop, triggering alarms.

Global end-diastolic volume, intrathoracic blood volume, and extravascular lung water.

A known quantity of dye or indicator is injected into a central vein and measured distally from a peripheral arterial blood sample.

Risk of barotrauma and anaesthetic agent dilution.

The fresh gas flow will also contribute to filling the bag.

In the presence of atracurium.

The inspiratory port leaf valve seals the expiratory port, allowing gases to enter the patient.

The inspiratory port leaf valve may not seal well, allowing fresh gas to escape and reducing supply to the patient.

In the pulmonary artery to measure PA pressure and sample mixed venous blood.

It is a reliable method for ensuring the desired concentration of inhalational agent is administered when used with audible alarms.

Via a pin-indexed system incorporating a bodok seal for a gas-tight connection.

The alveolar gas is vented through the pressure release valve to avoid rebreathing.

To control the flow of air during expiration and inspiration.

To reduce the risk of accidental awareness during general anaesthesia and to titrate the dose of anaesthetic agent.

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.

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.

The EtCO2 trace would still be present, but the patient would not receive fresh gas flow.

Gently squeeze the bag when they inspire to help open the valves and reduce resistance.

A pre-use check to ensure the correct functioning of the machine and equipment.

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.

It is vented through the APL valve and lost from the system, avoiding rebreathing.

Through thermodilution methods.

Hypoxia, ECG changes (most likely bradycardia), hypotension, and potentially cardiac arrest.

It draws in air from the room and oxygen from the reservoir bag.

It can keep the inspiratory port continuously open, risking hyperinflation of the lungs.

Via a transpulmonary thermodilution technique.

To vent off gas mixtures at pressures greater than 35 kPa, preventing barotrauma to flow meters and vaporisers.

The non-co-axial ‘Magill’ system.

Left atrial filling pressure and left ventricular end-diastolic pressure (LVEDP).

Fresh gas flows of 2.5 × MV.

Approximately 500 ml.

The end-tidal CO2 will not rise despite the patient rebreathing.

By tracking the power of the arterial waveform rather than its contour.

The Stewart–Hamilton equation: q = v (TB – T1)K1 K2 TB(t)dt.

The patient would continue to breathe room air and may wake up.

To trigger and record oesophageal contractions for generating the oesophageal contractility index.

The patient inhales fresh gas from the supply and from the deflating reservoir bag.

0.8 cm H2O during inspiration and 1 cm H2O during expiration.

Efficient at 70 ml/kg/min.

To receive compressed gases from their supplies (pipeline or cylinder).

They reduce the pressure of cylinder gases to approximately 400 kPa to protect the machine from high gas pressures.

A self-inflating bag with a non-rebreathing valve and mask.

It produces a dimensionless number between 0 and 100 to measure the depth of anaesthesia.

To allow the patient to draw oxygen and gases during deep inspiration.

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.

They act as an emergency source of gases if primary piped gas delivery fails.

Conditions creating an interfering pressure gradient, such as mitral stenosis, positive end-expiratory pressure (PEEP), and pulmonary hypertension.

2.83%.

They use electrodes on the forehead to measure EEG activity, which is processed using proprietary algorithms.

It allows for the application of CPAP and controlled ventilation.

The area under the curve (AUC) by recognizing the dicrotic notch on the arterial waveform.

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.

Mechanical (rotameters) and electronic flowmeters.

To ensure gas flows out of the bag into the patient during inspiration and prevents exhaled gases from re-entering the bag.

Cardiac output.

Stroke distance.

To ensure gas-specific connections that are permanently fixed.

Pulmonary Capillary Wedge Pressure (PCWP) values are 4–12 mmHg.

Approximately 2600 mL.

It closes to prevent atmospheric air from entering.

Because it offers resistance.

Fraction of inspired oxygen.

The bobbin shifts to close the inspiratory port, allowing exhaled gases to escape.

Tunstall, an obstetric anaesthetist, in 1977.

It has no valves or reservoir bag, making it a very low resistance system.

Due to its low resistance.

It includes an open-ended reservoir bag connected to the end of the tubing.

Fick's principle to CO2.

It is efficient for controlled ventilation at a flow rate of 70 ml/kg/min.

10 ml ice-cold 0.9% saline or 5% dextrose.

10 l/min.

It indicates surgical anaesthesia where auditory processing is possible but memory recall is less likely.

Waters' circuit, although this is technically inaccurate.

Airway gas measurement.

A second peak seen on the concentration-time curves due to the recirculation of the dye or indicator, which limits the number of measurements.

Gas from the anatomical dead space, which does not contain CO2 and is not depleted of O2.

It correlates directly with the speed of blood traveling in the aorta.

Mapleson E.

Prioritised preset alarms with audible and visual components, which can be individualised.

It analyzes raw EEG data by breaking it down into constituent sine waves.

No, both are not reliable with arrhythmias.

FiO2, oxygen flow rate, reservoir bag volume, inspiratory flow rate, respiratory rate, and valve type.

Ayre's T-piece.

It fills the bag and vents dead space gas along with alveolar gas, which avoids rebreathing but is wasteful and inefficient.

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.

When the oxygen supply pressure falls below 2 bar.

The presence of a trained, competent anaesthetist.

Fresh gas flows down the inner tubing while exhaled gas enters the outer tubing.

CO2, air flow, and airway pressures.

Mapleson C has shorter tubing compared to Mapleson B.

The dead space volume is expelled into the breathing system, passing down the tubing and fills the reservoir bag again.

2.5 × mV, the same as for spontaneous ventilation.

Inspiratory port, expiratory port, patient port, and one-way valve.

They may indicate that the patient is awake or aware.

To assess the patient's awareness during anaesthesia based on auditory responses.

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.

Hypotension, impaired cardiac function, increased nausea and vomiting, and delayed recovery.

Squeezes the bag to force gas into the patient.

They can significantly increase the work of breathing and impair passive expiration.

At least 60 dB for a minimum of 7 seconds.

The patient inhales fresh gas from the supply and from the reservoir bag, which deflates proportionally.

It can be used to reduce awareness in those patients.

Due to newer, relatively less invasive methods of cardiac output monitoring becoming available.

It relies on changes in electrical impedance of the thoracic cavity during blood ejection from the heart, which reflects cardiac output.

Reduction of the effect of reflected waves.

Velocity of blood flow in the descending thoracic aorta.

Oxygen, inhalation agent, end-tidal carbon dioxide concentration, gas volume, and airway pressure.

Not tolerated by awake patients, operator dependent, and risk of oesophageal perforation.

It is inefficient for spontaneous ventilation at flow rates of < 2.5 × mV.

Lithium dilution technique.

Heterogeneity and uncertainty due to individual responses, diverse case mixes, and variations in clinical practice.

Transcutaneous Doppler and transthoracic electrical bioimpedance.

Stroke volume variation (SVV), pulse pressure variation (PPV), and systolic pressure variation (SPV).

Cerebrocortical activity increases.

Supplies 100% oxygen at rates between 35 and 75 l/min, bypassing flowmeters and vaporisers.

A self-inflating bag, an alternative source of oxygen, relevant airway equipment, and emergency drugs.

2.5 × MV (minimum 3 L/min).

To analyze the concentration-time curve and calculate cardiac output based on the area under the curve (AUC).

Its reliability decreases in critically ill patients, and it has not gained wide clinical acceptance.

Jackson-Rees modification.

To vent waste gases and overcome the problem of rebreathing.

RA (1–7) mmHg.

Absence of sympathetic activity does not exclude awareness, and autonomic responses are uncommon in reported accidental awareness cases.

Molybdenum steel, which is lighter and stronger than carbon steel.

It has an inner tube surrounded by an outer one, designed to reduce bulkiness.

It is measured to determine cardiac output in the pulmonary circulation.

They do not produce the same pattern of EEG changes as other anaesthetic agents.

70 mL/kg/min.

Cardiac output is inversely related to AUC.

To avoid rebreathing.

They are produced with anti-static material to prevent the bobbin from sticking.

Mapleson C (Waters' circuit).

Stroke volume variation (SVV), systolic pressure variation (SPV), and pulse pressure variation (PPV).

By detecting temperature changes with a thermistor and applying the Stewart–Hamilton method.

They govern the transition from high- to low-pressure systems, reducing pressure as gas enters the flowmeter block.

The ventilator would alarm as the bellows would not be able to fill.

1500 ml.

It compares bis-guided anaesthesia with standard care in patients at increased risk of awareness.

A back-up, rechargeable battery.

Modified Stewart–Hamilton equation to calculate cardiac output.

Yes, they can be used in awake patients.

Changes in vessel wall diameter.

From minute ventilation including its CO2 content.

Visual and audible indicators.

Allows excess gas to escape when a preset pressure is exceeded, reducing barotrauma risk.

They prevent the inadvertent delivery of a hypoxic-inspired gas mixture.

Cardiac output is inversely related to the area under the curve (AUC).

Often coloured blue ('blue to bag').

Pulse pressure (PP) and area under the systolic portion of the waveform (AUC).

Insertion of an arterial line.

It is quick to set up, easy to use, and useful for estimating trends in cardiac output.

They measure the irregularity in spontaneous brain and facial muscular activity.

Using colour-coded, flexible hosepipes that connect via a Schrader valve.

The target range is 40-60.

Continuous beat-to-beat monitoring.

PA (25/10) mmHg.

22 mm male outer diameter/15 mm female internal diameter.

They convert volatile liquid into vapour and add a controlled amount of volatile to the fresh gas flow.

Often coloured yellow or gold ('gold for go').

The product of the cross-sectional area of the aorta and the stroke distance.

250 ml.

It heats up the blood in a semi-random manner to provide continuous cardiac output data.

Black = air, white = oxygen, blue = nitrous oxide.

It is used to calculate cardiac output.

To prevent barotrauma.

To allow entrainment of air if the oxygen supply does not meet respiratory demands.

It provides an objective assessment of sympathetic stimulation.