Critical closing pressure during midazolam-induced sleep

Abstract

The critical closing pressure (Pcrit) is the airway pressure at which the airway collapses and reflects the anatomical contribution to the genesis of obstructive sleep apnea. Pcrit is usually determined during non-rapid eye movement sleep at night, but has been determined under midazolam sedation during the day in the absence of sleep stage monitoring. Indeed, little is known about the effects of midazolam on sleep architecture. Moreover, deeper sedation with midazolam can decrease upper airway muscle activity and increase collapsibility compared with natural sleep. Pcrit under sedation has not been systematically compared with the usual method performed during natural sleep. Therefore, this study aimed to test the hypothesis that Pcrit following low doses of midazolam during the day would be comparable to Pcrit measured during natural sleep in the same patient. Fifteen men (age 54 ± 10 yr, body mass index 30 ± 4 kg/m(2)) with obstructive sleep apnea underwent a baseline standard overnight polysomnogram (apnea-hypopnea index 38 ± 22 events/h, range: 8-66 events/h), and Pcrit was determined during natural sleep and following midazolam. Sleep induction was obtained with low doses of midazolam (2.4 mg, range 2.0-4.4 mg), and sleep architecture was comparable to natural sleep. Natural sleep and induced sleep Pcrit were similar (-0.82 ± -3.44 and -0.97 ± 3.21 cmH(2)O, P = 0.663) and closely associated (intraclass correlation coefficient = 0.92; 95% confidence interval, 0.78-0.97, P < 0.001). Natural and midazolam-induced Pcrit correlated with obstructive sleep apnea severity, indicating that both Pcrit measures provided meaningful physiological information. Pcrit determined during the day with sleep induction is similar to natural overnight sleep and is a valid alternative approach in which to determine Pcrit.

Trazodone Increases the Respiratory Arousal Threshold in Patients with Obstructive Sleep Apnea and a Low Arousal Threshold

“…31 However, when light sedation using midazolam is used to induce a sleeplike state, upper airway collapsibility is similar to natural sleep. 32 This finding is consistent with the current study in which upper airway collapsibility and sleep parameters were similar before versus after trazodone.…”

Different Craniofacial Characteristics Predict Upper Airway Collapsibility in Japanese-Brazilian and White Men

“…Sleep was induced with midazolam as described previously. 17 Briefly, 0.5 mg of midazolam diluted in a saline solution was slowly infused IV (3 min). If the subject awoke and was not able to fall asleep again within 10 min, an additional dose of midazolam was administered until stable sleep was achieved.…”

“…The passive critical closing pressure (Pcrit) can assess anatomic predisposition to OSA. 5,17 With a view toward understanding the causal pathways to OSA development, we hypothesized that Japanese-Brazilians and whites would present different predictors of upper airway collapsibility. To test this hypothesis, Japanese-Brazilian and white men well matched for age and OSA severity (full polysomnography [PSG]) underwent Pcrit measurements and had their upper airway anatomy studied by CT scan and body fat composition determined by abdominal CT scan.…”

Upper Airway Collapsibility Assessed by Negative Expiratory Pressure while Awake is Associated with Upper Airway Anatomy

“…However, we have previously demonstrated that Pcrit determined during induced sleep by low doses of midazolam was similar to Pcrit during natural sleep. 22 NEP and Pcrit were performed in different conditions. NEP was assessed during wakefulness while Pcrit was assessed during sleep.…”

“…The infusion was restarted if the patient arose and was not able to fall sleep again in 10 min. 22 Patients slept in the supine position with all PSG channels (except for nasal pressure and thermistor), a well-fitted nasal mask attached to a heated pneumotachograph (Hans Rudolph, model 3700A), and a differential pressure transducer (Validyne, Northbridge, CA) for measurements of flow and pressure. The mask was connected to a modified CPAP device (Philips Respironics) that could deliver both positive and negative pressures.…”