RST Therapeutic Interventions and Titration Questions and Answers — Questions and Answers
Question 1: A 45-year-old male on a CPAP titration study continues to have obstructive hypopneas and loud snoring at a pressure of 14 cm H2O. The technologist increases the pressure to 15 cm H2O, but the patient awakens and complains of difficulty exhaling. According to AASM guidelines, what is the most appropriate next step?
- Decrease CPAP to 13 cm H2O and add a chin strap.
- End the titration and recommend a different mask interface.
- Add supplemental oxygen at 1 L/min.
- Switch to Bi-level PAP therapy. (Correct answer)
Correct answer: Switch to Bi-level PAP therapy.
The AASM guidelines recommend considering a switch to Bi-level PAP when CPAP pressures reach high levels (e.g., 15 cm H2O) and are associated with patient intolerance or persistent events. The patient's complaint of difficulty exhaling is a classic sign of pressure intolerance that Bi-level PAP, with its lower expiratory pressure (EPAP) and higher inspiratory pressure (IPAP), is designed to address.
Question 2: Which of the following conditions is a primary contraindication for the use of Adaptive Servo-Ventilation (ASV) therapy?
- Complex Sleep Apnea Syndrome.
- Chronic, symptomatic heart failure with reduced left ventricular ejection fraction (LVEF ≤ 45%). (Correct answer)
- Cheyne-Stokes Respiration with preserved ejection fraction.
- Opioid-induced central sleep apnea.
Correct answer: Chronic, symptomatic heart failure with reduced left ventricular ejection fraction (LVEF ≤ 45%).
ASV therapy is contraindicated in patients with chronic, symptomatic heart failure (NYHA 2-4) with a reduced left ventricular ejection fraction (LVEF ≤ 45%). The SERVE-HF trial found an increased risk of cardiovascular mortality in this specific patient population when treated with ASV. The other conditions are potential indications for ASV therapy.
Question 3: According to AASM guidelines, supplemental oxygen should be initiated and titrated during a PAP study under which of the following conditions?
- The patient's SpO2 is consistently ≤ 88% for at least 5 minutes despite an optimally titrated PAP pressure that has eliminated respiratory events. (Correct answer)
- The patient's SpO2 drops to 89% for 2 minutes despite an open airway.
- The patient has an AHI of 6 events/hour with associated desaturations.
- The patient reports shortness of breath at the beginning of the study.
Correct answer: The patient's SpO2 is consistently ≤ 88% for at least 5 minutes despite an optimally titrated PAP pressure that has eliminated respiratory events.
The AASM guidelines state that supplemental oxygen may be added during a PAP titration when the SpO2 is ≤ 88% for 5 minutes or longer in the absence of obstructive respiratory events. This ensures that the hypoxemia is not a result of airway obstruction that could be resolved by increasing PAP pressure. Oxygen is initiated at 1 L/min and titrated to maintain SpO2 between 88% and 94%.
Question 4: During a Bi-level PAP titration for obstructive sleep apnea, the technologist has set the EPAP to 8 cm H2O, which has eliminated apneas. However, the patient continues to have obstructive hypopneas and snoring. What is the correct action to resolve the remaining events?
- Increase the EPAP to 10 cm H2O.
- Decrease the EPAP to 6 cm H2O.
- Increase the IPAP to 12 cm H2O. (Correct answer)
- Decrease the Pressure Support by lowering IPAP.
Correct answer: Increase the IPAP to 12 cm H2O.
In Bi-level PAP titration, EPAP is primarily titrated to eliminate obstructive apneas. Once apneas are resolved, IPAP is then increased to eliminate hypopneas, snoring, and RERAs. Increasing the IPAP while keeping the EPAP stable increases the pressure support (the difference between IPAP and EPAP) and addresses the less severe respiratory events.
Question 5: Which of the following best defines an "optimal" PAP titration according to AASM guidelines?
- The AHI is reduced to < 10 events/hour for at least 30 minutes.
- All snoring is eliminated for the entire duration of the study.
- The SpO2 nadir remains above 90% for at least 15 minutes, regardless of the RDI.
- The RDI is reduced to < 5 events/hour for at least 15 minutes, including supine REM sleep. (Correct answer)
Correct answer: The RDI is reduced to < 5 events/hour for at least 15 minutes, including supine REM sleep.
An optimal titration is achieved when the Respiratory Disturbance Index (RDI), which includes apneas, hypopneas, and RERAs, is reduced to less than 5 events per hour for at least a 15-minute duration. Critically, this period must include sleep in the supine position and REM sleep, as sleep-disordered breathing is often at its worst under these conditions. The SpO2 should also be above 90%.
Question 6: A patient on CPAP at 12 cm H2O has a persistent large leak that is obscuring the airflow signal and causing multiple arousals. The technologist has already tried to refit and adjust the nasal mask straps without success. What should be the technologist's next action?
- Increase the CPAP pressure to 14 cm H2O to compensate for the leak.
- Switch the patient to a different size or style of mask, such as an oronasal mask. (Correct answer)
- Add a chin strap to prevent mouth breathing.
- Document the leak and continue the titration at the current pressure.
Correct answer: Switch the patient to a different size or style of mask, such as an oronasal mask.
When a large leak persists despite proper adjustments of the current mask, the mask itself is likely a poor fit for the patient's facial structure or sleep position. The most effective next step is to try a different size or style of mask. An oronasal (full-face) mask is often a good alternative for patients with significant mouth leaks or difficult nasal mask fits. Simply increasing the pressure would worsen the leak, and continuing without resolving it compromises the titration's quality.
RST Therapeutic Interventions and Titration Questions and Answers
A 45-year-old male on a CPAP titration study continues to have obstructive hypopneas and loud snoring at a pressure of 14 cm H2O.
The technologist increases the pressure to 15 cm H2O, but the patient awakens and complains of difficulty exhaling.
According to AASM guidelines, what is the most appropriate next step?