Mixed Deck — All RST Topics Flashcards

In the pathophysiology of obstructive sleep apnea (OSA), which factor is considered the most critical contributor to the repeated collapse of the upper airway during sleep?

Answer: Reduced activity of the genioglossus and other pharyngeal dilator muscles.

The primary pathophysiological mechanism in OSA is the failure of the upper airway pharyngeal dilator muscles, such as the genioglossus, to maintain airway patency during sleep. While anatomical narrowing is often a prerequisite, the functional collapse occurs due to the sleep-related reduction in neuromuscular activity that would normally keep the airway open.

Which organization is the primary accrediting body for sleep disorders centers in the United States?

Answer: American Academy of Sleep Medicine (AASM)

The AASM is the primary accrediting body for sleep disorders centers and laboratories in the United States, setting clinical and technical standards.

A 6-year-old child is scheduled for a polysomnogram and is visibly fearful of the electrodes and sensors. Which of the following is the MOST effective technique to facilitate the hookup process?

Answer: Use a "tell-show-do" approach, demonstrating the sensors on a doll or the parent first.

The "tell-show-do" technique is a well-established method for reducing anxiety in pediatric patients. By first explaining the procedure in simple terms (tell), then demonstrating on a non-threatening object like a doll or parent (show), and finally applying the sensor to the child (do), the technologist demystifies the process and builds trust.

Which of the following is a key component of providing effective patient education on sleep hygiene?

Answer: Instructing the patient to establish a consistent sleep-wake schedule, even on weekends.

A core principle of good sleep hygiene is maintaining a regular sleep-wake cycle. Going to bed and waking up at approximately the same time each day helps to regulate the body's internal clock, or circadian rhythm, promoting better sleep quality.

A 70-year-old male with a history of congestive heart failure (CHF) undergoes a polysomnogram. The recording shows a cyclical crescendo-decrescendo pattern of breathing effort and airflow, followed by a central apnea. This pattern is characteristic of Cheyne-Stokes Respiration. What is the primary pathophysiological driver of this breathing pattern in this patient?

Answer: Prolonged circulation time between the lungs and the brainstem chemoreceptors.

In patients with CHF, a prolonged circulation time delays the brainstem's chemoreceptors from sensing changes in blood gases (PaCO2) that occur in the lungs. This leads to a delayed and exaggerated ventilatory response. The ventilatory control system "overshoots," causing hyperventilation and a drop in PaCO2, which then leads to a central apnea. As CO2 builds back up, the cycle repeats, creating the classic Cheyne-Stokes pattern.

Which parameter is critical for scoring Cheyne-Stokes respiration?

Answer: Cyclic crescendo-decrescendo breathing ≥3 cycles

CSR requires a crescendo-decrescendo pattern with central apneas/hypopneas.

During physiological calibrations prior to starting a polysomnogram, the technologist asks the patient to look left, then right, then up, then down. What is the primary purpose of this specific set of maneuvers?

Answer: To verify correct signal response and polarity of the EOG channels.

These specific eye movements create predictable, out-of-phase deflections in the left and right electrooculogram (EOG) channels. This bio-calibration allows the technologist to confirm that the EOG electrodes are placed correctly and are functioning with the correct polarity, which is essential for accurately identifying the rapid eye movements that define Stage R sleep.

Which condition is associated with the 'paradoxical insomnia' complaint of severe sleep deprivation despite normal PSG findings?

Answer: Sleep State Misperception

Sleep State Misperception (SSM), also known as paradoxical insomnia, is a condition where individuals consistently underestimate their total sleep time and overestimate their sleep latency, despite objective polysomnographic findings showing normal sleep duration and quality. Patients genuinely believe they are getting very little sleep, even when sleep studies indicate otherwise. This discrepancy between subjective complaint and objective data is the defining characteristic.

When taking a patient's sleep history, it is most important to ask about their use of alcohol and tobacco before bedtime because these substances can:

Answer: cause fragmentation of sleep and worsen sleep-disordered breathing.

Both alcohol and nicotine can disrupt the normal sleep cycle. While alcohol may initially promote sleep onset, it leads to fragmented sleep and can worsen the severity of sleep apnea. Nicotine is a stimulant that can make it harder to fall asleep and stay asleep.

What is the minimum recommended digital sampling rate for EEG channels in polysomnography according to AASM technical specifications?

Answer: 200 Hz

The AASM specifies a minimum sampling rate of 200 Hz for EEG to adequately capture the full clinically relevant frequency range per the Nyquist theorem.

Which element is a key component of a sleep laboratory's infection control program?

Answer: Written protocols for cleaning, disinfection, and sterilization of reusable equipment

Written, systematic protocols for equipment cleaning, disinfection, and sterilization are the foundation of a compliant infection control program.

According to AASM scoring rules, what is the minimum duration required to score an apnea event?

Answer: 10 seconds

According to the American Academy of Sleep Medicine (AASM) scoring rules, an apnea event in adults is defined as a complete cessation or near-complete cessation of airflow for a minimum duration of 10 seconds. This standardized duration ensures consistency and accuracy in diagnosing sleep-disordered breathing events. It helps distinguish significant breathing pauses from normal respiratory variations.

When a technologist discovers an unreliable SpO2 signal during a study, what is the appropriate quality assurance response?

Answer: Troubleshoot and correct the signal, documenting all actions taken in the study record

Troubleshooting to restore signal quality is the priority, and all corrective actions must be documented to maintain data integrity and meet quality standards.

Which of the following is required to score a hypopnea in an adult patient?

Answer: ≥30% airflow reduction with ≥3% desaturation or arousal

According to AASM scoring criteria for adults, a hypopnea is scored when there is a discernible reduction in airflow of at least 30% from baseline, lasting for at least 10 seconds. This reduction must also be accompanied by either an oxygen desaturation of 3% or greater, or an associated arousal from sleep. Both criteria (airflow reduction and physiological impact) must be met.

During physiological calibrations, the technologist observes that when the patient looks to the left, the E1 (left eye) and E2 (right eye) channels produce in-phase deflections. What does this indicate?

Answer: A reversed electrode placement in the E1 or E2 derivation.

With standard EOG electrode placement (E1 below the left outer canthus, E2 above the right outer canthus, both referenced to M2/M1), conjugate eye movements should produce out-of-phase deflections. For example, looking left causes a negative deflection in E1 and a positive deflection in E2. If the signals are in-phase, it suggests one of the exploring electrodes may be referenced incorrectly or placed on the wrong side, requiring troubleshooting before the study begins.

Adaptive Servo-Ventilation (ASV) is a therapeutic option for specific types of sleep-disordered breathing. However, its use is contraindicated in which of the following patient populations due to increased mortality risk?

Answer: Patients with heart failure and a left ventricular ejection fraction (LVEF) of ≤ 45%.

The SERVE-HF trial demonstrated an increased risk of cardiovascular mortality in patients with chronic, symptomatic heart failure (NYHA 2-4) with a reduced left ventricular ejection fraction (LVEF ≤ 45%) and moderate to severe predominant central sleep apnea who were treated with ASV. Therefore, ASV is contraindicated in this specific population.

Which of the following is true about nasal pressure transducers?

Answer: They detect airflow via pressure fluctuations

Nasal pressure transducers are sensors used in polysomnography to detect airflow by measuring subtle pressure changes in the nasal cavity during breathing. As air is inhaled and exhaled, the pressure within the nasal cannula fluctuates, providing a highly sensitive and accurate waveform representation of airflow. This method is often preferred over thermistors for its ability to detect subtle flow limitations.

A patient being prepared for a polysomnogram expresses significant anxiety about being able to sleep with all the wires and sensors attached. What is the technologist's BEST response?

Answer: "I understand your concern. The sensors are designed to be as comfortable as possible, and I'll be monitoring you all night to ensure your safety and comfort. We don't expect a 'perfect' night's sleep, just a typical one for you."

Acknowledging the patient's feelings, providing reassurance about the process, and managing expectations are key communication skills for a sleep technologist. This response validates the patient's anxiety, explains that the equipment is designed for comfort, and clarifies the goal is to obtain a representative sample of their sleep, which helps to alleviate pressure to perform.

How are periodic limb movements (PLMs) scored?

Answer: ≥4 movements lasting 0.5-5 seconds, 5-90 seconds apart

PLMs are scored when ≥4 movements occur sequentially (5-90 sec apart) with EMG increases ≥8μV.

Which polysomnographic finding is diagnostic for REM Sleep Behavior Disorder (RBD)?

Answer: Elevated EMG tone during REM sleep

REM Sleep Behavior Disorder (RBD) is characterized by the loss of normal muscle atonia during REM sleep, leading to dream enactment behaviors. Polysomnography (PSG) confirms RBD by showing elevated or sustained submental EMG (electromyogram) tone, or excessive phasic EMG activity, during REM sleep, often accompanied by complex motor behaviors captured by video. This abnormal muscle activity during REM sleep is the diagnostic hallmark.