CPSGT common mistakes
CPSGT · Understand the traps and how to avoid them.
Computes the AHI with the wrong denominator - divides apneas plus hypopneas by total recording time or time in bed instead of total sleep time, then reports a number that is too low.
Candidates memorize the formula as 'events per hour' without pinning down which hours, and many sample reports display both an AHI and an events-per-recording-hour figure side by side.
What to do instead
Before doing any arithmetic, write the words 'divided by total sleep time' on scratch paper, pull TST from the scored epoch totals, and sanity-check that TST is less than time in bed. Confirm the number is per hour of sleep, not per hour of recording.
Applies adult event thresholds to a pediatric record - for example, refusing to score a hypopnea in a child because there was no 3% oxygen desaturation, or requiring a 10-second duration for a pediatric apnea.
Most study material and most real-world exposure is adult; the pediatric exceptions are a small block of rules that are easy to skim and forget.
What to do instead
Build a two-column adult-versus-pediatric table for apnea duration (10 seconds versus at least two breaths), hypopnea amplitude drop (30% versus 50%), and the desaturation or arousal requirement, and recite it before every pediatric practice set.
Places EEG and reference electrodes by eyeballing the scalp or by copying the position of a previous patient instead of measuring the 10-20 system from the nasion and preauricular points.
Time pressure at lights-out and the belief that 'close enough' placement will still produce a readable tracing.
What to do instead
Use a tape measure and grease pencil every time: mark nasion, inion, and both preauricular points, take the halfway measurement, then step off 20% increments and confirm that left and right distances are equal before attaching anything.
Moves on after hookup without checking impedance, or accepts a channel that is far above the laboratory limit and plans to 'watch it' during the night.
Impedance screens are a separate step and a high reading can still look like a plausible waveform on the display, so nothing appears broken.
What to do instead
Run the impedance check on every channel after the patient is settled and before lights out; re-prep and re-check any outlier, then re-verify after the patient has lain down and moved, since drying gel and lying on an electrode both change the reading.
Skips the pre-recording function check, so a dead thermistor, a reversed leg lead, or a snore sensor plugged into the wrong jack is not discovered until the middle of the night.
The check feels redundant when the waveforms already look 'alive' on screen, and it is easy to compress when the patient is drowsy and the tech is behind schedule.
What to do instead
Run a fixed maneuver checklist with the patient awake - blink, look left and right, clench the jaw, sniff, breathe through the nose, mouth-breathe, lift each leg, and hold the breath - and confirm the expected channel responds to each command before starting the study.
Scores artifact as physiology - counts sweat sway as delta activity, reads EKG or pulse artifact as EEG slowing, or calls a 60 Hz interference burst a spindle.
The scoring screen compresses hours of data and the artifact can look convincing at a glance, especially when the candidate is scanning quickly for stage markers.
What to do instead
For any suspicious waveform, verify it in the referential and the contralateral derivations, check whether it is time-locked to the EKG or pulse channel, and confirm that it has a physiologic morphology; artifact appears in channels that share a reference and disappears when the montage changes.
Classifies respiratory events from the wrong channel - scores hypopneas off the thermistor, or labels an event obstructive when the effort belts are flat.
All the respiratory channels sit next to each other on the screen and all show a deflection during an event, so the distinctions blur under time pressure.
What to do instead
Fix the channel roles in memory before scoring: nasal pressure for hypopnea amplitude, thermistor (or the designated airflow channel) for apnea, RIP or PAP-derived flow for effort and obstruction. For every event, look at both effort belts and the flow channel together before choosing a label.
Leaves documentation gaps - no time-stamped notes for interventions, position changes, mask adjustments, patient complaints, or periods of known artifact, so the interpreting physician cannot tell whether a finding is real.
Charting is done from memory at the end of the shift or squeezed in between tasks, and candidates assume the raw tracing speaks for itself.
What to do instead
Write a note at the moment of the event with the clock time and the action taken, using a consistent phrase set (time, observation, intervention, patient response), and add an artifact note whenever a channel is known to be unreliable.
Notices a serious finding - a run of arrhythmia, a prolonged deep desaturation, or a patient in visible distress - and waits until morning or until the supervisor happens to walk by instead of escalating.
Entry-level candidates are trained to defer to the supervisor and are unsure which findings cross the line from interesting to urgent.
What to do instead
Learn the laboratory's escalation criteria in advance and act within scope: notify the supervising technologist or on-call clinician immediately, document the time and the response, and never leave an unstable patient alone while waiting for instructions.
Hands the patient a PAP mask with a quick 'try this' and no acclimation, then abandons the titration when the patient feels panicky or claustrophobic; the study ends early and cannot answer the referral question.
The technical setup gets all the attention during training, and mask desensitization is treated as a personality trait rather than a teachable skill.
What to do instead
Use a stepped routine: let the patient hold and inspect the mask awake, fit it with the device off, then on at low pressure, coach slow breathing, adjust fit and leak before increasing pressure, and document tolerance attempts and the patient's response.