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Flashcards in Anesthetic Machines Deck (18)

What is a vaporizer interlock system?

Absence of a vaporizer interlock device is considered an absolute indication that an anesthesia machine is obsolete. Absence of this device would allow 2 vaporizers to be turned on simultaneously, resulting in the ability to deliver dangerously high concentrations of anesthetic vapors as well as contamination of the downstream vaporizer with an agent from the upstream vaporizer.


T or F: All recently manufactured vaporizers deliver a decreased concentration of volatile anesthetic agent when the dial is turned clockwise. The inability to replace a vaporizer that has a reverse configuration (volatile anesthetic concentration is increased when the dial is turned clockwise) is considered an absolute indication of anesthesia machine obsolescence.



T or F: Notification by the manufacturer that it will no longer provide service for an anesthesia machine is not necessarily an indication of machine obsolescence. In that circumstance, responsibility for providing support for the machine becomes the responsibility of the user, and it is sometimes possible to contract with third-party vendors to continue to provide support.



T or F: Current standards mandate 30- or 19-mm connections in the scavenging system. Connections in a scavenging system that have the same size as connections in a breathing circuit (15 or 22 mm) can permit crossover connections, therefore the presence of 15- or 22-mm connectors in a scavenging system is considered an absolute indication of anesthesia machine obsolescence. Crossover connections between the scavenging
system may result in negative pressure or dangerously high pressure in the anesthesia circuit.



Describe the four portions of the capnogram.

1- Baseline- represents inspiration and exhilation from anatomic dead space, where there is no CO2. Should be zero on capnogram.
2- Upstroke- represents early phase of exhalation representing alveolar and dead space gas
3- Plateau- represents alveolar gas
4- Downstroke- represents beginning of inspiration

A normal capnogram should have a baseline equal to zero indicating no rebreathing, a brisk upstroke, a flat plateau, and a brisk downstroke.


The presence of an incompetent EXPIRATORY valve will show what on a capnogram?

The presence of an incompetent expiratory valve permits mixing of inhaled and expired gases at the Y connector, with subsequent rebreathing of CO2. In the capnogram, this will be evident as failure of the baseline to return to zero.


The presence of an incompetent INSPIRATORY valve will show what on a capnogram?

A prolonged downstroke is consistent with an incompetent inspiratory valve.


A capnogram demonstrating a steeple sign represents what abnormality?

The steeple sign is associated with what in the capillary sampling line. It occurs because the capnometer aspirates room air through the leak, resulting in dilution of exhaled gases and producing an abnormally low plateau during phase I exhalation. When the pressure in the circuit increases, contamination of exhaled gas by room air is terminated and the value of end-tidal CO2 increases.


According to NIOSH regulations, the highest concentration of volatile anesthetic contamination allowed in the OR atmosphere when administered in conjunction with nitrous oxide is:

0.5 ppm


Which valve prevents transfilling between compressed-gas cylinders?

Check valves allow for unidirectional flow of gases.


Which color nail polish would have the greatest effect on the accuracy of dual-wavelength pulse oximeters?

Blue- blue nail polish has a peak absorance similar to that of adult deoxygenated hemoglobin (near 660 nm), so it will have the greatest effect on the SpO2 readings by causing an artifactual and fixed decrease in the spO2 readings.


What is the minimum macroshock current required to elicit ventricular fibrillation?

50-100 mA


What is a line isolation monitor?

This monitor alarms when grounding occurs in the OR or when the maximum current that a short circuit could cause exceeds 2-5 mA. It does interrupt electrical current but won't prevent microshock or macroshock.


T or F: if the width of the BP cuff is too narrow or if the BP cuff is wrapped too loosely around the arm, the BP measuremnt by the device will be falsely elevated.



What is microshock?

Microshock refers to electric shock in or near the heart. A current as low as 50 microamps is sufficient to produce ventricular fibrillation.


Will the line isolation monitor protect against microshock?

No- the line isolation monitor has a 2000 microamp threshold for alarming.


What is the Diameter Index Safety System?

Refers to the interface between the pipeline source and the anesthesia machine. The DISS provides threaded, non-interchangeable connections for medical gas pipelines through the hospital as well as to the anesthesia machine.


What is the Pin Index Safety System?

The PISS has two metal pins located in different arrangements around the yoke on the back of anesthesia machines, with each arrangement for a specific cylinder.