PSG QUESTIONS AND ANSWERS GRADED A+

PSG QUESTIONS AND ANSWERS GRADED A+ Sleep onset Start of the first epoch scored as any stage other than W Vertex sharp waves Sharply contoured. Duration of 0.5 seconds. Max over central regions. If a subject does not produce the alpha rhythm, how can you score N1? EEG activity in the range of 4-7 Hz with slowing background frequencies Vertex sharp waves Slow eye movements K complex Negative sharp wave followed by a positive component. Usually max in the frontal regions. Duration of greater than or equal to 0.5 seconds. What has to occur for an arousal to be associated with a K complex? The arousal must be congruent with the k complex or occur no more than 1 second after termination of the k complex. Sleep spindle 11-16 Hz (most commonly seen 12-14 Hz) Duration of greater than or equal to 0.5 seconds Max in central regions When do you begin scoring N2? When one or more trains of sleep spindles and/or k complexes (unassociated with arousals) occur during the first half of that epoch or the last half of the previous epoch When do you end N2? Transition to W An arousal (change to N1 until a K complex or sleep spindles occur) A major body movement followed by slow rolling eye movements and LAMF EEG without k complexes or sleep spindles Transition to N3 or REM When do you score N3? When greater than or equal to 20% of the epoch consist of delta activity (75 uV) Max amplitude in the frontal regions How do you score stage R? REMs Low chin EMG tone Sawtooth waves present Transient muscle activity LAMF Sawtooth waves Trains of sharply contoured or triangular, often serrated (jagged edge) 2-6 Hz Max amp in central regions Often, but not always, preceding a burst of rapid eye movement Transient muscle activity Short irregular burst of EMG activity usually 0.25 seconds superimposed on low EMG tone. Maximal in association with rapid eye movements Alpha waves 8-13 Hz What is the frequency of LAMF? 4-7 Hz What does G1 and G2 represent? G1 = exploring electrode G2 = reference electrode How are output voltages determined? G1 - G2 What is the easiest method of determining frequency? Frequency is measured in Hz. Easiest method is to count the numbers of cycles in one second. What does sensitivity equal? Input signal voltage divided by pen deflection What is the paper speed in PSG? 10mm/sec What are the appropriate EMG settings? Hff = at least 70Hz Lff = set at or close to 10Hz Which filter does a DC amplifier not use? DC amp do not use HFF because the changes in voltages are very slow Thermoregulation Bodys ability to regulate its own temp What is the avrge sleep latency? 10-20min What percentage of sleep is normal for each stage? N1 5%-10% N2 40%-50% N3 20%-25% REM 20%-25% What is verified during the time axis alignment check? Vertical pen alignment If there is low amplitude in the airflow channel what should you NOT do? Recalibrate the amplifier How can you prevent electrical interference? Make the impedance of input electrodes similar Which sensors generate their own voltage and can be plugged in directly to the headbox? Thermocouple and piezo-electric Crystal band How does a ground loop occur? Patient is attached to more than one diagnostic device, each with its own patient ground connection If CPAP titration is started at 4cm, what would that be on EPAP and IPAP? EPAP: 4 IPAP: 4 What is required to administer oxygen to a patient? Physicians order and a flow meter What standard device is used to verify CPAP pressure? Water column manometer What are characteristics of N1 sleep Relatively low voltage mixed frequency EEG, slow rolling eye movements, and a normally active chin EMG. How do you identify hypoventilation during sleep? Measuring a reduction in amplitude in the airflow channel tracings What's the leading cause of 60Hz artifact? High and unequal electrode impedences What is the best method of correcting unwanted artifacts while the patient is asleep? Changing the input signal derivations If slow wave artifact appeared in 3 EEG channels with the same reference, what would you do? Eliminate the artifact by re-referencing the input signal derivation to a back up reference electrode If high frequency artifact appears in single EEG channel that shares a reference electrode with another channel, what would you do? Eliminate artifact by changing the input signal derivation to a back up exploring electrode What can cause strong EKG artifact? Poor electrode placement or high electrode impedences If low frequency artifact appears in EEG and EOG channels, what is the best response? Cool the patient down and if that doesnt work temporarily raise low freq filter to 1.0 What is the benefit of double referencing? Reducing EKG artifact in the EEG or EOG (think tied ear( Does a capnometer detect respiratory effort? No What is the primary difference between thermocouples and thermisters? Thermocouples generate their own electricity while thermisters do not. Which device uses a cuff and bladder system? Pneumatic respiratory transducer What is the pH a measurement of? What level is considered normal? The level of acidity of the blood 7.35-7.45 What is the PC02 measuring and what level is considered normal? The amount of carbon dioxide in the blood 30-40 What is the PO2 a measurement of? Oxygen What is HC03 and what are normal levels? Bicarbonate 17-27 A heavy smoker will have... An increased HC03 level What level of hemoglobin is considered normal? 15-20 What PO2 level is considered normal? Greater than 57 What does Sa02 measure and what level is considered normal? The percentage of hemoglobin that is saturated with oxygen Greater than 90 What heart problems can OSA lead to? Heart block, myocardinal infarction, pulmonary hypertension An increase of acidity in the blood produces... A decreased pH What is the main difference between Sp02 and Sa02? How they are detected At sleep onset, the chin EMG... Decreases in amplitude Sa02 The amount of O2 in the blood as read by an arterial blood gas Sp02 The amount of O2 in the blood as read by a pulse oximeter