A
recent examination was conducted among a small group of acute respiratory
failure survivors to understand their problem of insomnia, including sleep
apnea as insomnia is a frequent complaint among survivors of critical illness.
The
study involved a small group of about 20 patients with acute respiratory
failure. These patients an acute need for at least 48 hours of mechanical
ventilation. The evaluation included the Insomnia Severity Index and in-home
level II overnight polysomnography three months after hospital discharge.
Sleep-disordered breathing was evaluated with the Apnea-Hypopnea Index (AHI)
and the Respiratory Distress Index (RDI). The AHI is used to measure the
average number of apneas (breathing cessations) and hypopneas (partial
obstructions) per hour. The Respiratory Distress Index (RDI) is used to measure
the average number of respiratory disturbances per hour. An RDI of 15 or
greater is considered clinically relevant to sleep quality and daytime function
and an AHI of 15 or greater can be a risk factor for cardiovascular morbidity.
Among
the patients who underwent polysomnography, the majority met criteria for
clinically-relevant sleep apnea, with 90% having an RDI of 15 or greater and
70% having an AHI of 15 or greater. The Oxygen desaturations were generally
mild. So, Insomnia severity did not significantly correlate with the presence
of sleep-disordered breathing.
It
was observed that some patients had clinically significant sleep apnea despite
their lack of sleep complaints. So, it was concluded that evaluating and
treating sleep apnea may significantly impact the health and well-being of
these patients. It was also concluded that the incidence and severity of sleep
apnea observed among acute respiratory
failure survivors are a cause for concern.
In the
study, it was observed that trauma was the triggering event for acute
respiratory failure in 58% of patients. In the provided report, 30% were
actively taking an opiate pain medication at the time of testing. Opiate
medication can worsen sleep apnea by reducing upper
airway tone and central respiratory drive. Hence the results suggested that
sleep apnea is common after acute respiratory
failure, with central-acting medications serving as one of the potential
contributors.