Need to complete an assigment generating a Report from spreadsheet using simple math formula
marebs
psg_report.docxUsing the sample data from the "Sample Score Sheet for Module 8," calculate each parameter listed in the "PSG Report Spreadsheet." Enter the results of your calculations in column B of the spreadsheet, and then organize and complete a PSG report.
Sleep/Wake Data
Two of the primary parameters reported are the “lights out” and “lights on” times (in hr:min format). It is important to also document epoch numbers for “lights out” and “lights on” when manually calculating sleep/wake activity. The total recording time (or time in bed) in minutes is calculated from this data.
Time calculations are based on epoch numbers, with the number of epochs divided by two (for 30-second epochs) to determine the time, in minutes. The following definitions will be useful for analyzing the scored data.
· Sleep onset—Sleep onset is defined as the start of the first epoch scored as any stage other than stage W. This is usually the first epoch of stage N1.
· Total sleep time—Total sleep time (in minutes) is calculated by subtracting the wake time between lights out and lights on from the recording time. The amount of time spent in each sleep stage is calculated in minutes. The time is calculated by adding the number of epochs scored as each stage and dividing by two (for 30-second epochs).
· Wake time—Wake time includes all wake time during the recording. Wake after sleep onset includes only wake time occurring during the recording after sleep onset and does not include wake before sleep.
· Wake after sleep onset—Wake after sleep onset (WASO) is calculated by totaling the wake time scored during the total recording time and subtracting the sleep latency (in minutes).
· Sleep latency—Sleep latency is the calculation of the time, in minutes, from lights out until sleep onset.
· REM latency—REM latency is calculated from sleep onset to the first epoch of stage R sleep.
· The percentage of total sleep time—The percentage of total sleep time (TST) spent in each sleep stage is determined by dividing the recorded time (in minutes) of each sleep stage by the total sleep time (in minutes) and multiplying by 100 percent.
· Sleep efficiency—Sleep efficiency is calculated as the total sleep time divided by the total recording time and multiplied by 100. Sleep efficiency is expressed in the form of a percentage.
A breakdown of sleep time into NREM and REM sleep is often calculated. To determine the amount of NREM sleep recorded, total the recording time (in minutes) for each NREM sleep stage, stage N1 through stage N3.
Arousal Events
The total number of arousals occurring in the record is reported as a number and as an arousal index (number of arousals per hours of sleep). The arousal index is calculated by multiplying the number of arousals by 60 and dividing by total sleep time (in minutes). Most computerized programs have the ability to link arousals to respiratory or limb movement events, which allows reporting of the number of events that caused arousals as well as an index by event type.
Respiratory Events
For those who prefer to score respiratory events separately, the following parameters must be displayed to accurately score respiratory events:
· Airflow—Thermal sensor
· Airflow—Nasal pressure transducer, CPAP flow, or CO2 flow
· Effort—Thoracic
· Effort—Abdominal
· Snoring microphone
· SaO2
The most comprehensive portion of the polysomnography report is the respiratory analysis. The number and type of events recorded are calculated for the entire recording. These variables include:
· the number of each type of respiratory event scored (obstructive apnea, central apnea, mixed apnea, and hypopnea)
· the total number of apneas plus hypopneas scored
· an apnea index (AI)
· a hypopnea index (HI)
· an apnea plus hypopnea index (AHI)
· the number of respiratory effort related arousals (RERAs) scored
· an RERA index
· a respiratory disturbance index (RDI)
· the mean oxygen saturation value
· the minimum oxygen saturation recorded during sleep
An apnea index (total number of apneas per hour of sleep) is calculated by adding the number of obstructive apnea (OA), mixed apnea (MA), and central apnea (CA) events scored, multiplying the total by 60, and dividing that number by the total sleep time in minutes.
AI = [(OA + MA + CA) x 60] / TST (in minutes)
A hypopnea index (total number of hypopneas per hour of sleep) is calculated by multiplying the total number of hypopneas scored by 60 and dividing that number by the total sleep time in minutes.
HI = [(no. of hypopneas) x 60] / TST (in minutes)
An apnea plus hypopnea index (total number of apneas and hypopneas per hour of sleep) is calculated by adding the total number of apnea and hypopnea events scored, multiplying the total by 60, and dividing that number by the total sleep time in minutes.
AHI = [(no. of apneas + no. of hypopneas) x 60] / TST (in minutes)
If RERAs are scored, the total number scored is documented along with an RERA index. The RERA index is calculated by multiplying the total number of RERAs scored by 60 and dividing that number by the total sleep time in minutes.
RERA Index = [(no. of RERAs) x 60] / TST (in minutes)
A respiratory disturbance index (total number of apneas, hypopneas, and RERAs per hour of sleep) is calculated by adding the total number of apnea, hypopnea, and RERA events scored, multiplying the total by 60, and dividing that number by the total sleep time in minutes.
RDI = [(no. of apneas + no. of hypopneas + no. of RERAs) x 60] / TST (in minutes)
Some reports further evaluate respiratory events by indicating the number of events and/or an index of respiratory events occurring during NREM or REM sleep, by body position, and by their association with arousals or awakenings. Many computer systems can evaluate individual events (OA, MA, CA, hypopnea).
An analysis of the oxygen saturation levels recorded should include documentation of the patient’s awake SaO2 level, the mean (average) oxygen saturation level during sleep, and the lowest oxygen desaturation seen during sleep. A breakdown of the percentage of time spent at certain oxygen saturation levels is often calculated as well. Typically, this breakdown of saturation ranges includes the percentage of time spent with oxygen levels between 90 and 100 percent, 80 and 89 percent, 70 and 79 percent, etc. (see Figure 8.3 ). The occurrence of hypoventilation and Cheyne Stokes breathing pattern should be documented when observed.
Figure 8.3. Breakdown of saturation ranges.
When CO2 monitoring is performed, a similar analysis of the CO2 levels recorded should include documentation of an awake CO2 level and the mean (average) and highest CO2 levels seen during sleep.
Limb Movement Events
The PLM analysis includes a count of all limb movements that occur during sleep. Most reports provide a count of isolated limb movements, as well as periodic limb movements. The periodic limb movements scored are calculated as a PLM index per hour of sleep time. The number of events related to arousals and to awakenings is tabulated separately, and a PLM arousal index (PLMAI) is calculated per hour of sleep time.
The AASM recommended report parameters include:
· the number of PLMS movements scored (PLMs)
· the number of PLMS movements with arousals or awakenings
· the PLM index (PLMI)
· the PLM arousal index (PLMAI)
PLMI = [(no. PLMS) x 60] / TST (in minutes)
PLMAI = [(no. PLMS with arousals or awakenings) x 60] / TST (in minutes)
Limb movements occurring during wake are not typically scored or tabulated. However, the occurrence of limb movements during wake is noted, since there may be a correlation between limb movements occurring during wake and symptoms of restless legs syndrome (RLS).
The PSG Report
The PSG report can be arranged in nearly any format and can include graphs as well as data. (For a sample of a complete polysomnography report, see Course Documents.)
Reports are generally arranged to include the primary information required for interpretation in sections, starting with a demographics section that identifies the patient, type of study, and study date. The demographics section generally also identifies the referring and sleep physician, recording technologist, and scoring technologist.
Sleep Summary
A report of the data necessary to evaluate the night’s sleep includes documentation of recording parameters such as “lights out” and “lights on,” sleep and REM latencies, sleep efficiency, and a summary of sleep parameters sleep stages scored and the percentage of total sleep time spent in each stage (see Figure 8.5 ).
Figure 8.5. Sample sleep summary report.
Respiration Summary
The respiration summary provided by a computerized report is generally extensive, including a count of each type of respiratory event, as well as a range of event duration by type, and indexes calculated by event type, sleep state, and body position (see Figure 8.6 ). Computerization makes it easy to also calculate by more than one parameter, such as by position and sleep stage. It is important to understand how your program is calculating these indexes so that you can assure the calculations are accurate.
Figure 8.7. Sample treatment interval report.
Figure 8.8. Sample oxygenation summary report.
Limb Movement Summary
The limb movement summary (see Figure 8.10 ) provides a count of limb movements including total, those occurring in REM and NREM, movements with and without arousal, and those that are isolated and periodic. The most significant parameter in this section of the report is the PLM index.
Figure 8.10. Limb movement summary report.
