Microsleep as a marker of sleepiness in obstructive sleep apnea patients.

We hypothesized that: (a) the presence of microsleep (MS) during a Maintenance Wakefulness Test (MWT) trial may represent a reliable marker of sleepiness in obstructive sleep apnea (OSA) patients; (b) the number of MSs will be higher in sleepy versus non-sleepy patients with a borderline MWT mean sleep latency; and (c) scoring MS during MWT analysis may help physicians to recognize patients with a higher degree of sleepiness. We analysed the MWT data of 112 treatment-naïve OSA patients: 20 with short sleep latency (SL, sleep latency <12.8 min), 43 with borderline latency (BL, sleep latency between 12.8 and 32.6 min) and 49 with normal latency (NL, sleep latency >32.6 min). Microsleep was identified in all SL, in 42 BL and in 18 NL patients, with a median latency of 5.6 min. Accordingly, patients were classified into two subgroups: group A (n = 43) with microsleep latency <5.6 min and group B (n = 69) with microsleep latency >5.6 min when present. The mean sleep latency in the MWT was 14.5 ± 7.5 min in group A and 34.6 ± 7.4 min in group B (p < 0.0001). The number of microsleep episodes during each MWT trial was higher in group A than in group B. Sleep latency survival curves demonstrated different patterns of sleep latency in these groups (log-rank test <0.0001). This finding was confirmed in a Cox proportional hazard analysis: the presence of a mean MS latency <5.6 min is associated with an increasing risk of falling asleep during the MWT (RR, 1.93; 95 CI 1.04-3.6; p = 0.03). We conclude that the detection of microsleep may help in discriminating OSA patients with and without daytime vigilance impairment.

Switch of Nocturnal Non-Invasive Positive Pressure Ventilation (NPPV) in Obstructive Sleep Apnea (OSA).

Background. Continuous positive airway pressure (CPAP) is considered the first-line treatment for patients with OSA, but Bilevel-PAP (BiPAP) therapy is a recognized option for noncompliant/unresponsive patients to CPAP. The present study was designed to evaluate the role of ResMed VAuto in the management of two different issues raised because of the Philips recall: the treatment of naïve noncompliant/unresponsive patients to CPAP (Group A) and the switch to VAuto for patients already on treatment with Philips Auto-BiPAP (Group B). Methods. Sixty-four patients who required auto-BiPAP treatment from August to December 2021 were included in the study. The efficacy of each mode of PAP therapy was compared between the two groups of patients. Results. Group A showed a statistically significant improvement in the apnea−hypopnea index (AHI) (7.4 ± 8.5 events·h−1 vs. 15.2 ± 12.1 events·h−1, p < 0.001), and oxygen desaturation index (ODI) (9.4 ± 8.9 events·h−1 vs. 15.2 ± 8.8 events·h−1, p = 0.029) during VAuto in comparison to CPAP, respectively. Conversely, a similar trend was found for patients in Group B for global AHI, but a statistically significant reduction was just found in supine AHI and ODI. In group B, an AHI <5 events·h−1 was found in 89.3% during VAuto in comparison to 82.1% with Philips Auto-BiPAP (p = ns). The levels of IPAPmax and EPAPmin were not statistically different between the two devices (p = 0.69 and p = 0.36, respectively). Conclusion. Bilevel ventilation in VAuto mode is effective in the clinical management of two different issues derived from the Philips recall. The switching between two different auto-BiPAP devices can be performed easily and successfully.

Anxiety and depressive symptoms on continuous positive airway pressure: long-term adherence in patients with sleep apnea syndrome.

BACKGROUND: Obstructive sleep apnea (OSA) is often associated to mood disorders and anxiety symptoms that may influence negatively the treatment approach. However, the relationship between anxiety, depression and adherence to treatment is still unclear. We investigate the presence of anxiety and depressive symptoms in newly diagnosed OSA patients and the link between psychological symptoms and acceptance or adherence to CPAP after one year. METHODS: A validated Italian questionnaire for anxiety and depressive symptoms was administered to 249 patients (69F) with a mean age of 57.2±12.2 and a mean AHI of 40.9±21.9 (ev*hr-1). The CPAP use in the first and last night of acclimatization and one year after prescription was 6.4±2.2, 6.9±1.4 and 5.3±2.2 hr, respectively. RESULTS: Anxiety symptoms were reported by 15.6% of patients, depressive symptoms by 6% while 12.5% reported both anxiety and depressive symptoms. Adherence to CPAP in the first night was not adequate in 19.7% of patients with relevant difference between groups: 16.4% in AD-,20.5% in A+,13.3% in D+ and 38.7% in AD+ (χ2=8.6; P=0.03). However, at the end of acclimatization period only 4.4% of patients utilized CPAP<5/h. One-year after prescription the adherence was adequate in 74.7% of patients without difference between groups. A Cox proportional hazard model demonstrated that AHI (OR=0.985, 95% CI: 0.97-0.99; P=0.03) and compliance to CPAP at the first night of use (OR=0.445; 95% CI: 0.246-0.8; P=0.007) are the only predictive factors of long-term compliance. CONCLUSIONS: Presence of anxiety and depressive symptoms should be checked before PAP titration since they may negatively influence the early acclimatization and adherence.

The relationship of daytime hypoxemia and nocturnal hypoxia in obstructive sleep apnea syndrome.

QUESTION OF THE STUDY: Prevalence and determinants of daytime hypoxemia in patients with obstructive sleep apnea (OSA) syndrome are not well established. The aims of this study, conducted in a large series of OSA patients, were to estimate the prevalence of daytime hypoxemia, to assess the reciprocal effects between daytime PaO2 and nocturnal SpO2, and to investigate the direct and indirect role of sleep apnea severity in determining feedback gas exchange abnormalities. MATERIALS AND METHODS: In 456 patients a daytime hypoxemia-nocturnal hypoxia feedback structural equations model was designed. PaO2 adjusted for age (% of predicted), percent sleep time spent with SpO2 <90% (TST90), oxygen desaturation index and the apnea-hypopnea index, were determined as the measures of daytime hypoxemia, nocturnal hypoxia, and sleep apnea severity, respectively, after adjusting for the severity of obesity and lung volumes. RESULTS: The TST90-PaO2 feed-back structural equations modeling showed that daytime PaO2 was inversely related (P<0.001) to nocturnal hypoxia (-4.0% of PaO2 per 1 SD of TST90). The severity of OSA (-1.0%) was an indirect determinant of daytime PaO2 via the TST90 pathway. In contrast, daytime PaO2 did not influence (P>0.05) the extent of nocturnal hypoxia. CONCLUSIONS: In OSA patients, the extent of nocturnal hypoxia seems to be both a direct determinant and a mediator of the indirect effect of sleep apnea on the development of daytime hypoxemia.

Effect of sleep on patient/ventilator asynchrony in patients undergoing chronic non-invasive mechanical ventilation.

BACKGROUND: Patients who require home non-invasive ventilation (NIV) during sleep normally have the ventilation settings adjusted empirically during daytime wakefulness. However, patient-ventilator asynchrony may occur during sleep. To detect the incidence of ineffective efforts (IE) during the sleep compared to wakefulness, we studied 48 patients already enrolled in a long-term home NIV programme. METHODS: We evaluated arterial blood gases, breathing pattern during spontaneous breathing (SB) and ventilation during wakefulness. In addition, we assessed the breathing pattern and oxygen gas exchange during night-time NIV. RESULTS: Daytime NIV significantly improved blood gases compared to SB (PaO2 NIV 10.2 +/- 1.95 kPa vs PaO2 SB 8 +/- 1.37, p < 0.001; PaCO2 NIV 5.75 +/- 1.08 kPa, vs PaCO2 SB 6.5 +/- 1.25, p < 0.001). The IE index was higher during sleep compared to wakefulness (48 +/- 39.5 events/h versus 0 +/- 0). The IE index was correlated with the time spent with SaO2 < 90% (r = 0.39, p < 0.01), but not with ventilator parameters, underlying disease, ventilation mode or type of mask. Eight patients had an IE index >100 events/h; these patients had a faster respiratory rate, required a higher level of inspiratory assistance and had poor gas exchange during sleep. CONCLUSIONS: We conclude that IE to breath are common during nocturnal NIV and that they may be associated with desaturations even in patients who are considered compliant and effectively treated.

Sleep disturbances in patients admitted to a step-down unit after ICU discharge: the role of mechanical ventilation.

BACKGROUND: Severe sleep disruption is a well-documented problem in mechanically ventilated, critically ill patients during their time in the intensive care unit (ICU), but little attention has been paid to the period when these patients become clinically stable and are transferred to a step-down unit (SDU). We monitored the 24-h sleep pattern in 2 groups of patients, one on mechanical ventilation and the other breathing spontaneously, admitted to our SDU to assess the presence of sleep abnormalities and their association with mechanical ventilation. METHODS: Twenty-two patients admitted to an SDU underwent 24-h polysomnography with monitoring of noise and light. RESULTS: One patient did not complete the study. At night, 10 patients showed reduced sleep efficiency, 6 had reduced percentage of REM sleep, and 3 had reduced percentage of slow wave sleep (SWS). Sleep amount and quality did not differ between patients breathing spontaneously and those on mechanical ventilation. Clinical severity (SAPS(II) score) was significantly correlated with daytime total sleep time and efficiency (r = 0.51 and 0.5, P < 0.05, respectively); higher pH was correlated with reduced sleep quantity and quality; and higher PaO(2) was correlated with increased SWS (r = 0.49; P = 0.02). CONCLUSIONS: Patients admitted to an SDU after discharge from an ICU still have a wide range of sleep abnormalities. These abnormalities are mainly associated with a high severity score and alkalosis. Mechanical ventilation does not appear to be a primary cause of sleep impairment.