Third 50 Flashcards
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The fall time constant is also called…?
Signal decay
A good way to decrease current leakage is…?
Use shorter power cords
Which channel type produces a square calibration wave?
DC channel (SpO2)
Which device receives and transmits signals from 0 to 1 volt?
DC amplifier
What respiratory effort device uses coiled bands that are stretched during respiration?
Inductive plethysmograph
A time constant of 1 second is equal to an LFF setting of …?
0.16 Hz
Amperes are measured in ….?
Coulombs / second (frequency reading)
When electrical signals from external sources interfere with signals derived from the patient, this is referred to as…?
Stray capacitance
Which parameters does EtCO2 detect?
Airflow, SpO2, exhaled CO2
What is the danger of using two ground wires on a piece of diagnostic equipment?
Electric shock
Which device produces its own electricity?
Thermister, Oximeter, Piezo-electric crystal band, Actigraph
Piezo-electric crystal band
The positioning of the pens along the horizontal plane is called…?
Time axis
What is seen in the transition from wake to N1 sleep?
Slow eye movements, some epileptiform activity, low voltage mixed-frequency EEG
What is seen in relaxed wakefulness with eyes OPEN?
low-voltage mixed frequency EEG, elevated chin EMG, Rapid eye movement / blinks
What is seen in relaxed wakefulness with the eyes CLOSED?
Elevated chin EMG, Alpha rhythm, slow rolling eye movements
What is the frequency of alpha waves?
8-13 Hz
What is the frequency of theta waves?
4-7 Hz
What are characteristics of N1 sleep?
Low voltage mixed EEG, slow rolling eyes, normally active chin EMG
How does hypoventilation present?
Slight reduction in airflow for an extended period of time
If a patient has OSA and the obstruction is at the nasal passages, what would be most appropriate?
Surgery
What are characteristics of Cheyne-Stokes?
Cyclic SpO2 decreases, Respiration improves during REM, Waxing and waning pattern in airflow and effort channels
What is a normal base excess?
-2.5 to 2.5
What is a normal Hb level ?
15-20
What is a normal PO2 level?
Greater than 57
What is the main difference between SaO2 and SpO2?
How they are detected
In most sleepers what happens to the chin EMG at sleep onset?
The amplitude decreases
What is the required desaturation for a hypopnea with 50% or greater decrease in airflow?
3%
What is the required duration of an apnea?
10 seconds
Characteristics of patients with hypoxic drive:
Breathe based on O2 levels rather than CO2 levels and typically do not respond well to PAP.
What is a type of lead not used during MSLT?
Leg leads
What is the mean sleep latency for MSLT?
All sleep onset times added, then divided by the number of them (4-5 naps during the day)
What is the mode sleep latency for MSLT?
The mode is the time that occurs most frequently.
What is the median sleep latency for MSLT?
Place the numbers in numerical order and it is the one in the middle
How long should naps last in MSLT (lights on)?
15 minutes AFTER sleep onset
What is an MWT?
Maintenance of Wakefulness testing
If a patient does not enter REM during the first four naps of MSLT, what should be done?
Allow the pt to go home unless protocol says otherwise
What percentage of sleep is N2 in normal, healthy adults?
About 50%
What is known as the Circadian Rhythm Oscillator ?
Suprachiasmatic Nucleus
How many minutes is the length of the average human sleep cycle?
90 minutes
When is physiological sleepiness in adults the highest?
Afternoon
What happens to blood pressure in REM?
BP increases during REM sleep
Why is REM also called paradoxical sleep?
The body is paralyzed although the EEG resembles a waking pattern
In which age group are nocturnal sleep / daytime alertness usually at optimal levels?
Children
What occurs in aging adults re: sleep?
Decreased N3 sleep, Changes in REM sleep, Decreased REM latency and sleep latency.
Is blood pressure stable during REM?
No, it actually goes up
What is the narcolepsy tetrad?
excessive daytime sleepiness (EDS), cataplexy, hypnagogic hallucinations, and sleep paralysis
Which brain structure sends signals from the body to the cortex?
Thalamus
Which brain structure BLOCKS signals from the thalamus to the cortex?
Reticular activating neurons
What is seen in the EEG when the thalamus is blocked?
sleep spindles
