Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

APEX Flashcards 2025 > UNIT 6 Equipment & Monitors > Flashcards

UNIT 6 Equipment & Monitors Flashcards

(97 cards)

Start Studying
1
Q

What components are present in the high-pressure system of the anesthesia machine?
What is the gas pressure in this region?

A

Components include:
* Hanger yoke
* Yoke block with check valves
* Cylinder pressure gauge
* Cylinder pressure regulators

Gas pressure = cylinder pressure

This system starts at the cylinders and ends at the cylinder regulators.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What components are present in the intermediate pressure system?

A

Components include:
* Pipelines
* Flowmeter valve
* Pipeline inlets
* Pressure gauges
* Ventilator power inlet
* Oxygen pressure failure system
* Oxygen second stage regulator
* Oxygen flush valve

Gas pressure = 50 psi (if using pipeline), 45 psi (if using tank)

from pipelines to flowmeter valve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What components are present in the low-pressure system?

A

Components include:
* Flowmeter tubes (Thorpe tubes)
* Vaporizers
* Check valves
* Common gas outlet

Gas pressure = slightly above atmospheric pressure

from flowmeter tubes to the common gas outlet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the 5 tasks of oxygen in the anesthesia machine?

A

Tasks include:
* O2 pressure failure alarm
* O2 pressure failure device (failsafe)
* O2 flowmeter
* O2 flush valve
* Ventilator drive gas (if pneumatic bellows)

These tasks ensure safe and effective oxygen delivery.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Describe the pin index safety system (PISS).

A

The PISS prevents inadvertent misconnections of gas cylinders.
Each tank is unique, making unintended connections unlikely, but not impossible!!!

The presence of more than one washer between the hanger yoke assembly and the stem of the tank may allow bypassing the PISS.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe the diameter index safety system (DISS).

A

The DISS prevents inadvertent misconnections of gas hoses.
Each hose and connector are sized and threaded for each individual gas.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the maximum pressure and volumes for cylinders that contain air, oxygen, and nitrous oxide?

A

Maximum pressures and volumes vary by gas type.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How long will an oxygen cylinder with a bourdon pressure gauge reading of 500 psi provide oxygen at a flow rate of 4L/min?

A

Approximately 43.5 minutes (1900 psi) or 41 minutes (2000 psi)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Is it ever safe to use an O2 tank in the MRI suite?

A

Not unless it’s aluminum!

An MRI-safe cylinder will have two colors: most of the tank is silver, and only the top signifies the gas it contains.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

List 3 safety relief devices that prevent a cylinder from exploding when the ambient temperature increases.

A

In a fire, there is a safety relief device built into the cylinder that allows it to empty its contents in a slow and controlled way.
* Fusible plug made of Wood’s metal (metls at elevated temps)
* Frangible disk that ruptures under pressure
* Valve that opens at elevated pressures

Cylinders should never be exposed to temperatures >130°F (57°C).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Give 1 example of how the oxygen pressure failure device (failsafe) might permit the delivery of a hypoxic mixture.

A

It responds to pressure – not flow!

If there is a pipeline crossover, the pressure of the second gas can defeat the failsafe device, exposing the patient to a hypoxic mixture.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Give 4 examples of how the hypoxia prevention safety device (proportioning device) might allow the delivery of a hypoxic mixture.

A

Examples include:
* Oxygen pipeline crossover
* Leaks distal to the flowmeter valves
* Administration of a third gas (helium)
* Defective mechanical or pneumatic components

These conditions can compromise the effectiveness of the device.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the difference between the oxygen pressure failure device and the hypoxia prevention safety device?

A

The oxygen pressure failure device responds to pressure, while the hypoxia prevention safety device ensures a minimum oxygen concentration in the gas mixture.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe the structure and function of the flowmeters.

A

a. the annular space is the area btwn the indicator float and the side wall of the flow tube. The annular space is the narrowest at the base and widest at the top. This “variable orifice” architecture provides a constant gas pressure throughout a wide range of flow rates.
* i. laminar flow is dependent on the gas viscosity (Poiseuille)
* ii. turbulent flow is dependent on gas density (graham)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the safest flowmeter configuration on the anesthesia machine?

A

O2 flowmeter should always be furthest to the RIGHT (in the USA).

b. flowmeters are made of glass = most vulnerable part of the anesthesia machine. A leak will allow oxygen to escape the low-pressure system, which could result in the delivery of a hypoxic mixture.
c. if a leak develops in any other flowmeters, it won’t reduce the FiO2…however, if a leak happens in the o2 flowmeter, all bets are off.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How do you calculate the Fio2 set at the flowmeter?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the total tidal volume delivered to the patient using fresh gas coupling?

A

Vt total = Vt set on ventilator + FGF inspiration

You may need to include volume lost to compliance in calculations.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

When using a ventilator that couples FGF to tidal volume, what types of ventilator changes will impact the tidal volume delivered to the patient?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the vaporizer splitting ratio?

A
  • a. modern variable bypass vapes split FG into 2 parts:
  • i. some fresh gas enters the vaporizing chamber & becomes 100% saturated with VA
  • ii. the rest of the gas bypasses the vape chamber & doesn’t pick up any VA
  • b. Before leaving the vaporizer, these 2 fractions mix, and this determines the final anesthetic concentration exiting the vaporizer.
  • c. By setting the concentration on the dial, you determine the splitting ration. Setting a higher concentration directs more FGF towards the liquid anesthetic, while setting a lower concentration directs less FGF towards it.

Higher concentration settings direct more fresh gas towards the liquid anesthetic.
Higher temps = more FGF to bypass VA.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the pumping effect?

A
  • The pumping effect increases vaporizer output.
  • b. anything that causes gas that has already left the vape to re-enter the vape chamber can cause the pumping effect.
    (PPV or the use of O2 flush valve)
  • c. Modern machine design mitigates this risk.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Compare/contrast the variable bypass vaporizer with the injector-type vaporizer.

A

Variable bypass vaporizers allow for variable gas flow, while injector-type vaporizers introduce anesthetic directly into the gas stream.

Each has distinct mechanisms for achieving anesthetic delivery.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What does the oxygen analyzer measure and where is it located?

A

It monitors O2 concentration (not pressure) and is located downstream of the flowmeters.

It is the only device that can detect a hypoxic mixture.

Leaks in the anesthesia machine are most likely to occur in the low-pressure system!!!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What 2 things must you do in the event of an oxygen supply line crossover?

A
  1. Turn on the O2 cylinder.
  2. Disconnect the pipeline O2 supply. (KEY STEP!!!)

i. simply turning on the O2 tank is not enough – if adequate oxygen pipeline pressure is present (regardless of gas inside), it will prevent the O2 tank from providing oxygen to the pt.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Pressing the oxygen flush valve exposes the breathing circuit to ____ O2 flow and ____ O2 pressure.

A

35-75 L/min and 50 psi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What are the risks of pressing the oxygen flush valve?
Risks include barotrauma and awareness. ## Footnote Pressing it during **inspiration** can cause barotrauma, and the gas does not pass through vaporizers, diluting anesthetic concentration.
26
Describe the function of the ventilator spill valve in relation to using the O2 flush valve.
The spill valve prevents excessive pressure in the ventilatory circuit when the O2 flush valve is activated. ## Footnote This helps maintain safe operating pressures.
27
Compare/contrast volume controlled and pressure-controlled ventilation.
Volume-controlled * i. preset Vt over a predetermined time. * ii. Inspiratory flow is held constant during inspiration iii. shark fins 🦈 Pressure-controlled * i. preset pressure over predetermined time. * ii. pt lungs mechanics decide the Vt and inspiratory flow variability * iii. if airway resistance rises or compliance ↓, Vt suffers, and a higher inspiratory flow is required to achieve preset airway pressure. * iv. top hat’s 🎩 ## Footnote Volume-controlled has constant inspiratory flow; pressure-controlled varies based on lung mechanics.
28
What conditions can alter the tidal volume delivered during pressure-controlled ventilation?
Conditions include changes in airway resistance and lung compliance. ## Footnote Increased resistance or decreased compliance can significantly affect tidal volume.
29
What is the best action to take if the soda lime has become exhausted during a procedure?
Increase minute ventilation (VE). ## Footnote This action helps remove CO2 but does not prevent rebreathing of CO2. Instead, if you can’t replace the CO2 absorbent, the appropriate action is to ↑ FGF to convert the circle system into a semi-open configuration.
30
What is desiccation and how does it apply to soda lime?
a. Water is required to facilitate the reaction of CO2 with CO2 absorbent. **The granules are hydrated to 13-20% by weight. ** b. when absorbent is devoid of water = desiccated. c. ethyl violet tells you about exhaustion, but it does not tell you about the water content. ## Footnote Desiccated soda lime + halogenated agents = CO (Des > Iso >>> Sevo) & compound A (sevo) i. CO --> carboxyhemoglobinemia ii. Compound A --> renal dysfunction
31
List 7 ways to monitor for disconnection of the breathing circuit.
pressure, volume, ETCO2, your own vigilance. Ways to monitor include: * Pressure monitoring * Volume monitoring * ETCO2 monitoring * Visual inspection of chest rise * Precordial stethoscope * Low expired volume alarm * Low peak pressure alarm ## Footnote **the oxygen analyzer monitors the concentration of oxygen in the breathing circuit – it is not a disconnect monitor! **
32
What are the OSHA recommendations regarding inhalation anesthetic exposure for healthcare workers in the OR?
Recommendations include: * Halogenated agents alone ≤ 2 ppm * Nitrous oxide alone ≤ 25 ppm * Halogenated + nitrous oxide ≤ 0.5 ppm & 25 ppm, respectively
33
Compare/contrast the 4 types of breathing circuits and list examples of each.
34
What is the purpose of the unidirectional valves in the breathing circuit?
To ensure gas flows in one direction and prevent rebreathing of exhaled gas. i. if a valve becomes incompetent, then the patient will rebreathe the exhaled gas. ii. the definitive fix is to correct the valve iii. if this can’t be done, then a closed or semi-closed system should be converted to a semi-open system by ↑ FGF in excess of pt’s minute ventilation. ## Footnote An incompetent valve requires correction to maintain system integrity.
35
Which Mapleson circuit is most efficient for spontaneous ventilation?
Mapleson A ## Footnote It is ranked A > DFE > CB for efficiency. B is the worst!
36
Which Mapleson circuit is most efficient for controlled ventilation?
Mapleson D ## Footnote It is ranked DFE > BC > A for efficiency. A is the worst!! **Most likely to see DEF circuits in practice!**
37
What conditions decrease pulmonary compliance?
Conditions include: * Endobronchial intubation * Pulmonary edema * Pleural effusion * Tension pneumothorax * Atelectasis * Chest wall trauma * Insufflation * Ascites * Trendelenburg position * Inadequate muscle relaxation ## Footnote These conditions can lead to increased peak and plateau pressures.
38
What conditions increase pulmonary resistance?
Conditions include: * Kinked endotracheal tube * Endotracheal tube cuff herniation * Bronchospasm * Bronchial secretions * Compression of airway * Foreign body aspiration ## Footnote Reductions in dynamic compliance affect peak pressure while plateau pressure remains unchanged.
39
Describe the 4 phases of the normal capnograph.
Phases include: * Phase I (A-B): Exhalation of anatomic dead space * Phase II (B-C): Exhalation of anatomic dead space + alveolar gas * Phase III (C-D): Exhalation of alveolar gas * Phase IV (D-E): Inspiration of fresh gas that does not contain CO2 ## Footnote Understanding these phases is crucial for assessing ventilation.
40
Discuss the significance of the alpha & beta angles on the capnograph.
* An increased alpha angle indicates expiratory airflow obstruction * An increased beta angle suggests rebreathing due to a faulty unidirectional valve. ## Footnote The beta angle may appear normal in cases of CO2 absorbent exhaustion.
41
Recall all of the abnormal CO2 waveforms you can have.
42
45. What factors affect the accuracy of noninvasive blood pressure (NIBP) readings?
Factors include: * Ideal bladder length (80% of extremity) * Width (40% of circumference of arm)
43
How does the site of measurement affect blood pressure reading?
* As the pulse travels from the aortic root to periphery, SBP increases while DBP decreases, leading to wider PP. * c. At aortic root: SBP is lowest, DBP is highest, PP is narrowest. * d. Dorsalis pedis: SBP is highest, DBP lowest, PP widest. ## Footnote **MAP remains constant throughout the arterial tree.**
44
How does arm position affect the NIBP reading? How about when an ART line is used?
* Cuff above heart = BP falsely low * cuff below heart = BP falsely high. * iii. for every 10 cm change = BP changes by 7.4 mmHg * iv. for every ↑ change, BP changes 2 mmHg * b. ART line – the transducer level is what's important here – the catheter height does not matter!
45
What information can you learn from the arterial line (ART) waveform?
46
Discuss dampening and the interpretation of the high-pressure flush test.
* a. Optimal waveform morphology balances the amount of dampening with the amount of distortion from the transducer system. The high-pressure flush test helps determine this when we flush the system and observe the oscillations that result (if any). * i. Optimally damped system: baseline is re-established after 1 oscillation * ii. Under-damped system: baseline is re-established after several oscillations (SBP is overestimated, DBP is underestimated, MAP is accurate) * iii. Over-dampened: baseline re-established with no oscillations (SBP is underestimated, DBP is overestimated, MAP is accurate). Causes include – air bubble or clot in pressure tubing or low flush-bag pressure.
47
How do you determine the appropriate distance to thread a central line or PA catheter?
48
What characterizes an optimally damped system?
Baseline is re-established after 1 oscillation.
49
What characterizes an under-damped system?
Baseline is re-established after **several** oscillations; SBP is overestimated, DBP is underestimated, MAP is accurate.
50
What characterizes an over-dampened system?
* Baseline is re-established with no oscillations; SBP is underestimated, DBP is overestimated, MAP is accurate. * Causes include air bubble or clot in pressure tubing or low flush-bag pressure.
51
What are the 3 waves and 2 descents on the CVP waveform?
A wave, C wave, V wave, X descent, Y descent.
52
What does the A wave on the CVP waveform signify?
Occurs after P wave (atrial depolarization).
53
What does the C wave on the CVP waveform signify?
Occurs just after QRS complex (ventricular depolarization).
54
What does the X descent on the CVP waveform signify?
Occurs during the ST segment.
55
What does the V wave on the CVP waveform signify?
Occurs just after T wave begins (ventricular repolarization).
56
What does the Y descent on the CVP waveform signify?
Occurs after T wave ends.
57
What factors can increase or decrease the CVP value?
Factors include blood volume, venous return, and intrathoracic pressure.
58
What conditions cause loss of the a-wave on the CVP waveform?
* Afib * V-pacing if the underlying rhythm is asystole.
59
What conditions cause an increased a-wave on the CVP waveform?
Tricuspid stenosis, diastolic dysfunction, myocardial ischemia, chronic lung disease leading to RVH, AV dissociation, junctional rhythm, V-pacing (asynchronous), PVCs. ## Footnote produced when atria contracts and empties against high resistance (valve or non-compliant ventricle)
60
What conditions cause a large v-wave on the CVP waveform?
* TR allows RV volume to pass through closed but incompetent TV during RV systole. This ↑ the volume and pressure in the RA = large v-wave. * conditions include: TR, acute increase in intravascular volume, RV papillary muscle ischemia.
61
What are the normal pressures at each step as the PA catheter is guided into position?
RAP: 1-10, RVP: 15-30/0-8, PAP: 15-30/5-15, PAOP: 5-15.
62
The tip of the PAC should be positioned in which West lung zone?
Zone 3. ## Footnote reflects LVEDP since there is a continuous column of blood btwn the tip of PAC and LV.
63
What is the equation for mixed venous oxygen saturation?
Q = CO, VO2 = oxygen consumption ## Footnote normal is 65-75%
64
What conditions are associated with a decreased SvO2?
65
What conditions are associated with an increased SvO2?
66
What is the relationship between phases of the cardiac AP and the EKG?
67
What region of the myocardium does each EKG lead monitor?
* 12 lead * 3 lead groups: Bipolar (3), Limb (3), Precordial (6).
68
List the conditions that can cause left and right axis deviation.
69
Recite the heart block poem.
* If R is far from P - then you have 1st degree * longer, longer, longer, drop – then you have a Wenckebach * if some Ps don’t get through – then you have Mobitz II * if Ps and Qs don’t agree – then you have 3rd degree.
70
What is the mechanism of action for each antiarrhythmic class (I-IV)?
* Class I: sodium channel blockers * Class II: beta blockers * Class III: potassium channel blockers * Class IV: calcium channel blockers
71
What EKG findings are consistent with WPW syndrome?
Delta wave, short PR interval (<0.12s), wide QRS, possible T wave inversion.
72
What conditions increase the risk of torsades de pointes?
a. POINTES b. Phenothiazines c. Other meds (methadone, Droperidol, amiodarone w/ hypokalemia) d. Intracranial bleed e. No known cause f. Type 1 antiarrhythmics g. Electrolyte disturbances (low K, Ca, Mg) h. Syndromes (Romano-Ward, Timothy)
73
What is the treatment for torsades?
Reverse underlying cause, MgSO4, cardiac pacing to increase HR.
74
List 5 indications for cardiac pacemaker insertion.
75
What is the significance of the NBG pacemaker ID code?
* Position 1 = chamber paced * position 2 = chamber sensed, * position 3 = response to sensed event, * position 4 = programmability, * position 5 = multiple pacing sites.
76
How does atrial pacing affect the QRS complex?
* A paced = normal, narrow QRS (electrical signal travels thru AV node) * V paced = QRS is widened (electrical signal is delivered beyond the AV node)
77
What conditions increase the risk of failed to capture?
a. this happens when the ventricle does not depolarize in response to pacing stimulus b. Hyper- or hypokalemia c. hypocapnia (intracellular K shift) d. hypothermia e. MI fibrotic tissue buildup around the pacing leads f. antiarrhythmic medications
78
How does the cerebral oximeter work?
a. uses near-infrared spectroscopy (NIRS) to measure cerebral oxygenation. * i. arterial hgb, venous hgb, and tissue cytochromes absorb different frequencies of infrared light. * ii. cerebral ox relies on the fact that cerebral blood volume is 1 part arterial : 3 parts venous  75% of blood in the brain is on the venous side of circ. * iii. Since NIRS can’t detect pulsatile blood flow, its primarily a measure of venous hgb sat and O2 extraction. * iv. ↓ in cerebral oxygen delivery  ↑ cerebral oxygen extraction  ↓ venous hgb sat. * * so brain is extracting more bc it’s getting less arterial bf
79
What value is considered a significant change from baseline in cerebral oximetry?
>25% change from baseline indicates decreased cerebral oxygenation.
80
How do brain waves change during general anesthesia?
* Induction of GA = increased beta waves * light anesthesia = increased beta waves * GA = theta & delta predominance * Deep anesthesia = burst suppression * 1.5-2 MAC = isoelectric
81
Name 2 drugs that are most likely to reduce the reliability of BIS value.
* a. N2O i. ↑ amplitude of high-frequency + reduced amplitude of low-frequency ii. DOES NOT AFFECT THE BIS VALUE! * b. Ketamine i. ↑ high-frequency activity; ii. higher BIS value than the level of sedation otherwise suggests…
82
What is the difference between macroshock and microshock?
a. Macroshock i. larger current applied to external surface of body (defib pads) ii. the skin’s impedance offers high resistance --> larger current needed to induce v.fib b. Microshock i. smaller current applied directly to myocardium (internal paddles) ii. skin’s high resistance is bypassed --> smaller current to induce v.fib iii. CVL, PA cath, or pacing wires = direct conductive pathway to heart
83
What are the key threshold values for macroshock & microshock?
84
What is the role of the line isolation monitor (LIM)?
* Assess the integrity of the ungrounded power system in the OR. * Tells you how much current could potentially flow through you or a patient if a second fault occurs. ## Footnote i. Purpose: alert OR staff of the 1st fault * does not (by itself) protect you or the pt from micro- or macroshock
85
What should you do if the line isolation monitor (LIM) alarms?
Unplug the last piece of equipment that was plugged in. ## Footnote Alarms when 2-5mA of leak current is detected
86
Causes of increased and decreased ETCO2 that occur as a result of change in CO2 production.
87
Causes of increased and decreased ETCO2 that occur as a result of changes in alveolar ventilation or equipment malfunction.
88
What wavelengths of light are emitted by the pulse ox? What law is used to make the SpO2 calculation?
a. Beer-Lambert law: relates the intensity of light transmitted through a solution and the concentration of the solute wihin the solution. b. Red light, 660 nm i. preferentially absorbed by deoxyhemoglobin (higher in venous blood) c. Near-infrared light, 940 nm i. preferentially absorbed by oxyhemoglobin (higher in arterial blood)
89
What conditions impair the reliability of the pulse oximeter?
a. ↓ perfusion i. vasoconstriction, hypothermia, Reynaud’s syndrome b. dysfunctional Hgb i. carboxyhgb (absorbs 660 nm to the same degree as oxygenated hgb) ii. methemoglobin (absorbs 660 and 940 equally!) iii. NOT HgbS or HgBF c. altered optical characteristics i. methylene blue ii. indocyanine green iii. indigo carmine iv. NOT fluorescein d. non-pulsatile flow i. CBP or LVAD e. Motion artifact i. shivering/movement f. Other i. electrocautery ii. dark skin iii. venous pulsation iv. NOT jaundice or polycythemia
90
What are examples of Class IA antiarrhythmics?
* Quinidine * Procainamide * Disopyramide ## Footnote Na channel blockers
91
What are examples of class IB antiarrhythmics?
* Lidocaine * Phenytoin ## Footnote Na channel blockers
92
List examples of class IC antiarrythmics.
* Flecainide * Propafenone ## Footnote Na channel blockers
93
How do each of the Class I (Na channel blockers) work? (A-C)
94
What are the class II antiarrhythmics? List examples. How do they affect the cardiac AP?
Beta blockers Esmolol, metoprolol, atenolol, propranolol
95
MOA for the class III antiarrhythmics. Examples. Affect on cardiac AP?
K channel blockers Amioderone, Bretyium
96
MOA of class IV antiarrhythmics. Examples. Affect on cardiac AP?
97
Describe the different types of EEG waveforms.

APEX Flashcards 2025 (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions