Safety and effectiveness in explantation and re-implantation of hypoglossal nerve stimulation devices.

PURPOSE: Since 2001, hypoglossal nerve stimulators have been implanted in patients with obstructive sleep apnea around the world, initially in trial situations but more recently also in regular care settings. Medium term data indicate effectiveness and tolerability of treatment. However, when assessing the safety of the procedure, the safe feasibility of explantation or reimplantation must also be considered. PATIENTS AND METHODS: Nine patients with an implanted respiratory-driven hypoglossal nerve stimulator. We have evaluated the feasibility and safety of explantation or re-implantation with another stimulation system. RESULTS: In 2012, nine patients were implanted with a respiratory-driven hypoglossal nerve stimulator as part of the Apnex Medical Pivotal Study. The study was ended in 2013. For a variety of reasons, the system was explanted from all nine patients by the year 2019. Three of these patients were re-implanted with a different system with respiratory sensing during the same session (mean incision to closure time for explantation 88.2 ± 35.01 min., mean incision to closure time for re-implantation 221.75 ± 52.73 min.). Due to extensive scar tissue formation, all procedures were technically challenging. Complication rate was significantly higher when re-implantation was performed or attempted in the same surgical session (0 of 5 patients with explantation versus 3 of 4 patients with attempted re-implantation; p = 0.018). There was no significant difference between the AHI values before and after implantation in patients with re-implantation. CONCLUSION: Explantation and re-implantation are technically challenging though possible procedures. The single-staged equilateral reimplantation of another hypoglossal nerve stimulation system can, but need not, be successful.

Comparison of effects of OSA treatment by MAD and by CPAP on cardiac autonomic function during daytime.

PURPOSE: The present study compared the effects of mandibular advancement therapy (MAD) with continuous positive airway pressure therapy (CPAP) on daytime cardiac autonomic modulation in a wide range of obstructive sleep apnea (OSA) patients under controlled conditions in a randomized, two-period crossover trial. METHODS: Forty OSA patients underwent treatment with MAD and with CPAP for 12 weeks each. At baseline and after each treatment period, patients were assessed by polysomnography as well as by a daytime cardiac autonomic function test that measured heart rate variability (HRV), continuous blood pressure (BP), and baroreceptor sensitivity (BRS) under conditions of spontaneous breathing, with breathing at 6, 12, and 15/min. RESULTS: Both CPAP and MAD therapy substantially eliminated apneas and hypopneas. CPAP had a greater effect. During daytime with all four conditions of controlled breathing, three-minute mean values of continuous diastolic BP were significantly reduced for both MAD and CPAP therapy. At the same time, selective increases due to therapy with MAD were found for HRV high frequency (HF) values. No changes were observed for BRS in either therapy mode. CONCLUSIONS: These findings indicate that both MAD and CPAP result in similar beneficial changes in cardiac autonomic function during daytime, especially in blood pressure. CPAP is more effective than MAD in eliminating respiratory events.

Auto bi-level pressure relief-PAP is as effective as CPAP in OSA patients--a pilot study.

PURPOSE: Continuous positive airway pressure (CPAP) is the therapy of choice for the treatment of obstructive sleep apnea (OSA). Not all patients can use CPAP therapy with adequate compliance. There is a need to develop more comfortable modes. Auto bi-level Pressure Relief-Positive Airway Pressure (ABPR-PAP) can be an alternative. We conducted a prospective double-blind, randomised trial to evaluate the efficacy and compliance of ABPR-PAP compared with CPAP in OSA patients. METHODS: We included 35 CPAP naive patients (age 53.3 ± 10.3 years, BMI 31.0 ± 5.0 kg/m(2), ESS 10.0 ± 4.2) diagnosed with moderate to severe OSA who underwent a successful CPAP titration. Patients were randomised into the CPAP or the ABPR-PAP treatment group. We used the same device (BIPAP® Auto, Philips Respironics) for CPAP or ABPR-PAP. Apnea-hypopnea index (AHI) was determined using polysomnography before (AHI 40.6 ± 18.3 per hour) and after treatment. RESULTS: Eighteen patients received CPAP and the remaining 17 received APBR-PAP. Groups were similar in terms of demographics and OSA severity. There were no serious adverse events during the trial. CPAP was fixed by a sleep expert and ABPR-PAP varied (range 5-15 cmH(2)O). AHI decreased in the CPAP group to 6.4 ± 5.7 per hour and in the ABPR-PAP group to 4.8 ± 3.6 per hour in the first night (N = 35). After 3 months, the AHI decreased in the CPAP group to 4.4 ± 5.3 per hour and in the ABPR-PAP group to 2.6 ± 3.8 per hour (N = 32). Differences between the groups were not statistically significant. There were no differences in compliance. CONCLUSIONS: ABPR-PAP is a promising new ventilation mode that enables effective treatment of OSA patients.

Case Study: Acute Lumbar Paraspinal Compartment Syndrome in an Austere Military Environment.

The incidence of compartment syndrome of the lumbar paraspinal muscles is exceedingly rare. Approximately 24 hours following a high-intensity kettlebell swing workout, a 33-year-old Sailor presented to the medical department on board a forward deployed Wasp-class amphibious assault ship with increasing discomfort in his middle and lower back, and evidence of rhabdomyolysis. Discomfort quickly turned to unrelenting pain coupled with dorsal paresthesias and rigidity in the paraspinal muscles. He was taken emergently to the operating room, where his paraspinal muscles were released via fasciotomy. As a result of limited resources aboard the deployed ship, a negative pressure wound dressing was fashioned using the supplies available aboard the ship. Following 3 days of the negative pressure wound therapy, muscle bulging decreased substantially, and the skin was closed. After 4 weeks of physical therapy, he returned to full duty.

Acute hearing loss, dysarthria, dysphagia, and a rubbery intraoral mass in an 18-year-old woman.

Rhabdomyosarcoma is the most common soft tissue tumor of childhood, frequently presenting in the head and neck, genitourinary tract, or extremities. We present a case of rhabdomyosarcoma in which an 18-year-old woman presented with abrupt onset unilateral hearing loss, tinnitus, dysarthria, dysphagia, and a new painless red bump on the palate. With an alveolar subtype and older age, both predictors of poor prognosis, early recognition of disease of these symptoms is vital.

Bi-level positive pressure ventilation and adaptive servo ventilation in patients with heart failure and Cheyne-Stokes respiration.

OBJECTIVES: Nocturnal positive pressure ventilation (PPV) has been shown to be effective in patients with impaired left ventricular ejection fraction (LVEF) and Cheyne-Stokes respiration (CSR). We investigated the effect of a bi-level PPV and adaptive servo ventilation on LVEF, CSR, and quantitative sleep quality. METHODS: Thirty-seven patients (New York heart association [NYHA] II-III) with LVEF<45% and CSR were investigated by electrocardiography (ECG), echocardiography and polysomnography. The CSR index (CSRI) was 32.3+/-16.2/h. Patients were randomly treated with bi-level PPV using the standard spontaneous/timed (S/T) mode or with adaptive servo ventilation mode (AutoSetCS). After 6 weeks, 30 patients underwent control investigations with ECG, echocardiography, and polysomnography. RESULTS: The CSRI decreased significantly to 13.6+/-13.4/h. LVEF increased significantly after 6 weeks of ventilation (from 25.1+/-8.5 to 28.8+/-9.8%, p<0.01). The number of respiratory-related arousals decreased significantly. Other quantitative sleep parameters did not change. The Epworth sleepiness score improved slightly. Daytime blood pressure and heart rate did not change. There were some differences between bi-level PPV and adaptive servo ventilation: the CSRI decreased more in the AutoSetCS group while the LVEF increased more in the bi-level PPV group. CONCLUSIONS: Administration of PPV can successfully attenuate CSA. Reduced CSA may be associated with improved LVEF; however, this may depend on the mode of PPV. Changed LVEF is evident even in the absence of significant changes in blood pressure.

Cardiac autonomic modulation and sleepiness: physiological consequences of sleep deprivation due to 40 h of prolonged wakefulness.

The autonomic nervous system (ANS) is modulated by sleep and wakefulness. Noninvasive assessment of cardiac ANS with heart rate variability (HRV) analysis is a window for monitoring malfunctioning of cardiovascular autonomic modulation due to sleep deprivation. This study represents the first investigation of dynamic ANS effects and of electrophysiological and subjective sleepiness, in parallel, during 40 h of prolonged wakefulness under constant routine (CR) conditions. In eleven young male healthy subjects, ECG, EEG, EOG, and EMG chin recordings were performed during baseline sleep, during 40 h of sleep deprivation, and during recovery sleep. After sleep deprivation, slow-wave sleep and sleep efficiency increased, whereas HRV - global variability and HRV sympathovagal balance - was reduced (all p<0.05). Sleep-stage-dependent analysis revealed reductions in the sympathovagal balance only for NREM sleep stages (all p<0.05). Comparison of the daytime pattern of CR day one (CR baseline) with that of CR day two (CR sleep deprivation) disclosed an increase in subjective sleepiness, in the amount of unintended sleep, and in HRV sympathovagal balance, with accompaniment by increased EEG alpha attenuation (all p<0.05). Circadian rhythm analysis revealed the strongest influence on heart rate, with less influence on HRV sympathovagal balance. Hour-by-hour analysis disclosed the difference between CR sleep deprivation and CR baseline for subjective sleepiness at almost every single hour and for unintended sleep particularly in the morning and afternoon (both p<0.05). These findings indicate that 40 h of prolonged wakefulness lead in the following night to sleep-stage-dependent reduction in cardiac autonomic modulation. During daytime, an increased occurrence of behavioral and physiological signs of sleepiness was accompanied by diminished cardiac autonomic modulation. The observed changes are an indicator of autonomic stress due to sleep deprivation - which, if chronic, could potentially increase cardiovascular risk.

Nocturnal snoring decreases daytime baroreceptor sensitivity.

BACKGROUND: In patients with obstructive sleep apnea heart rate variability and baroreceptor sensitivity during night and daytime are impaired. Snoring without obstructive sleep apnea may already influence heart rate variability and baroreceptor sensitivity during daytime. METHODS: Cardiovascular daytime testing was performed in 11 snorers and age, BMI, and gender matched controls. Sleep apnea and snoring were quantified by sleep recordings. Paced breathing was performed during daytime with ECG, non-invasive blood pressure, and respiration recorded. Heart rate variability and blood pressure variability were analyzed in the time and frequency domain. Baroreceptor sensitivity (alpha gain) was calculated. RESULTS: In snorers a significant increase in high frequency systolic blood pressure variability (SBPV-HF) compared to control group (0.37 mm Hg(2) vs. 0.11 mm Hg(2) for 12 breaths and 0.35 mm Hg(2) vs. 0.10 mm Hg(2) for 15 breaths) was demonstrated. Furthermore a lower baroreceptor sensitivity was found in snorers compared to controls (9.2 ms/mm Hg vs. 16.2 ms/mm Hg for 12 breaths and 8.5 ms/mm Hg vs. 17.4 ms/mm Hg for 15 breaths per minute) using the paced breathing protocol. Mean heart rate was elevated in snorers as well. CONCLUSIONS: Snorers may have a reduced parasympathetic tone during daytime rather than an increased sympathetic tone.

Daytime baroreflex sensitivity in patients with primary insomnia.

Insomnia has been linked to cardiovascular disease and among these especially hypertension and changes in autonomic function. One marker for cardiovascular risk is baroreflex sensitivity (BRS). We investigate daytime BRS in patients with primary insomnia in order to assess cardiovascular risk. Twenty-one patients (18 females/3 males) with primary insomnia according to DSM-IV were recruited. Careful investigations excluded confounding sleep disorders such as sleep-disordered breathing and periodic limb movements. An age-matched control group with 21 healthy subjects (18 females/3 males) underwent the same investigations. To assess BRS, an experimental protocol with paced breathing during daytime was performed. ECG and continuous non-invasive blood pressure were recorded to obtain spontaneous BRS by calculating the α index (BRS-α) and also by transfer function analysis (TF-BRS). There were no differences at daytime between insomnia patients and controls neither in BRS-α (8.1 ms/mmHg, range 5.8-14.7 vs. 9.6 ms/mmHg, range 6.9-15.8) nor in TF-BRS (5.8 ms/mmHg, range 2.4-16.8 vs. 5.4 ms/mmHg, range 2.3-11.4). Also there were no differences in absolute, low or high frequency bands of heart rate or blood pressure variability between the two groups. We could show that primary insomnia may be not associated with daytime parameters of autonomic imbalance (e.g., baroreflex sensitivity) which are known as non-classical risk markers of cardiovascular disease.

Positive airway pressure initiation: a randomized controlled trial to assess the impact of therapy mode and titration process on efficacy, adherence, and outcomes.

STUDY OBJECTIVES: (1) To determine the efficacy of automatically adjusted positive airway pressure (APAP) with a comfort feature (A-Flex) at reducing apneas and hypopneas in participants with moderate to severe OSA. (2) To determine the relative difference between A-Flex, continuous positive airway pressure (CPAP), and APAP-derived optimal pressure for CPAP (CPAP(APAP)) on adherence to treatment. (3) To determine the relative difference between APAP with A-Flex, CPAP, and CPAP(APAP) on long-term change in functional outcomes. DESIGN: Randomized, double-blinded, 3-arm, multicenter trial. SETTING: University and Veterans Affairs medical centers. PATIENTS OR PARTICIPANTS: 168 participants were randomized, and 140 completed the 180-day study. INTERVENTIONS: (1) A-Flex; (2) CPAP; (3) APAP for 14 days and then switched to CPAP at a fixed pressure. MEASUREMENTS AND RESULTS: Apnea-hypopnea indices, average and minimum oxygen saturation, time spent < 90% were significantly poorer for A-Flex vs. CPAP at the initiation of study treatment; with the exception of minimum oxygen saturation, these differences were absent at 180 days. A-Flex had lower average leak values at both 3 and 6 months. There were no significant differences between groups in major efficacy, adherence, and outcome (subjective sleepiness, objective vigilance, blood pressure, quality of life) measures. No differences between groups in attitudes toward use were observed at 3 or 6 months; participant ratings for CPAP were significantly higher than A-Flex on treatment satisfaction and benefit, but not different for sleep quality and mask comfort. CONCLUSIONS: We found that A-Flex shows equivalency, but non-superiority (except for average leak values), in efficacy, adherence, and functional outcomes compared to CPAP after either 3 or 6 months. CLINICAL TRIAL REGISTRY: Positive Pressure Treatment of Obstructive Sleep Apnea, http://www.clinicaltrials.gov, NCT00636181.

Preliminary results from a telemedicine referral network for early diagnosis of sleep apnoea in sleep laboratories.

We conducted a feasibility study to find out whether a simple preliminary examination using telemedicine for diagnosis was sufficient to identify sleep-related breathing disorders (SRBD). Night-time pulse oximetry recordings were made in normal home surroundings on patients suffering from sleep apnoea/SRBD by doctors with a range of non-specialist backgrounds. The readings were transmitted to the relevant sleep laboratory, examined and the results returned to the referring doctor. From 80 patients (aged 29 to 60 years), 58 complained about characteristic symptoms (snoring, daytime sleepiness); 33 of these patients showed additional symptoms of associated diseases. In eight patients associated diseases were found without any symptoms. The findings were compatible with SRBD in 58 cases (73%); 12 of these were asymptomatic patients. A total of 57 patients had to be referred to a sleep laboratory for differential diagnosis by full polysomnography. Of the 22 patients (28%) without pathological findings following pulse-oximetry, 12 were symptomatic. The system described here is suitable for the creation of referral networks and for the identification of patients from institutions not trained in sleep medicine, who would otherwise not have been referred for specific diagnosis to a sleep laboratory.