Coding note (for 780.57 [647.37] code only): When an opioid use disorder is present, first code the opioid use disorder: 305.50 (F1 1.10) mild opioid use disorder or 304.00 (F1 1.20) moderate or severe opioid use disorder; then code 780.57 (647.37) central sleep apnea comorbid with opioid use. When an opioid use disorder is not present (e.g., after a one- time heavy use of the substance), code only 780.57 (647.37) central sleep apnea comor- bid with opioid use.
Note: See the section “Diagnostic Features” in text.
Specify current severity:
Severity of central sleep apnea is graded according to the frequency of the breathing disturbances as well as the extent of associated oxygen desaturation and sleep frag- mentation that occur as a consequence of repetitive respiratory disturbances.
Idiopathic central sleep apnea and Cheyne-Stokes breathing are characterized by increased gain of the ventilatory control system, also referred to as high loop gain, which leads to in- stability in ventilation and PaCOz levels. This instability is termed periodic breathing and can be recognized by hyperventilation alternating with hypoventilation. Individuals with these disorders typically have pC02 levels while awake that are slightly hypocapneic or normocapneic. Central sleep apnea may also manifest during initiation of treatment of ob- structive sleep apnea hypopnea or may occur in association with obstructive sleep apnea hypopnea syndrome (termed complex sleep apnea). The occurrence of central sleep apnea in association with obstructive sleep apnea is also considered to be due to high loop gain. In contrast, the pathogenesis of central sleep apnea comorbid with opioid use has been at- tributed to the effects of opioids on the respiratory rhythm generators in the medulla as well as to its differential effects on hypoxic versus hypercapneic respiratory drive. These individuals may have elevated pC02 levels while awake. Individuals receiving chronic methadone maintenance therapy have been noted to have increased somnolence and de- pression, although the role of breathing disorders associated with opioid medication in caus- ing these problems has not been studied.
An increase in the central apnea index (i.e., number of central apneas per hour of sleep) re- ﬂects an increase in severity of central sleep apnea. Sleep continuity and quality may be markedly impaired with reductions in restorative stages of non—rapid eye movement (REM) sleep (i.e., decreased slow-wave sleep [stage N3]). In individuals with severe Cheyne-
Stokes breathing, the pattern can also be observed during resting wakefulness, a finding that is thought to be a poor prognostic marker for mortality.
Central sleep apnea disorders are characterized by repeated episodes of apneas and hy- popneas during sleep caused by variability in respiratory effort. These are disorders of ventilatory control in which respiratory events occur in a periodic or intermittent pattern.
Idiopathic central sleep apnea is characterized by sleepiness, insomnia, and awakenings due to dyspnea in association with five or more central apneas per hour of sleep. Central sleep apnea occurring in individuals with heart failure, stroke, or renal failure typically have a breathing pattern called Cheyne-Stokes breathing, which is characterized by a pattern of and hypopneas occurring at a frequency of at least five events per hour that are accompa- nied by frequent arousals. Central and obstructive sleep apneas may coexist; the ratio of central to obstructive apneas/hypopneas may be used to identify which condition is pre- dominant.