Work of breathing as a tool to diagnose severe fixed upper airway obstruction

A 4-year-old girl with bilateral vocal fold palsy was successfully decannulated from tracheotomy after seven laryngeal procedures. But an important stridor and dyspnea recurred 13 months after decannulation. Nocturnal gas exchange was normal but her daytime work of breathing was increased by fourfold, without any beneficial effect of nasal noninvasive continuous positive airway pressure ventilation (CPAP), reflecting a severe fixed airway obstruction. Endoscopic examination confirmed the work of breathing findings showing glottic and supraglottic stenosis. This upper airway obstruction was successfully treated with a recannulation. In conclusion, the major message of this case report is that measurement of the work of breathing was able to document the "fixed" nature of the airway obstruction, by showing no improvement even with highest tolerated levels of nasal CPAP. As such, the work of breathing may be proposed as a screening tool to quantify and assess the reversibility of severe upper airway obstruction in children.

Obstructive sleep apnea: an unexpected cause of insulin resistance and diabetes

Obstructive sleep apnea (OSA) is prevalent with type 2 diabetes. Conversely, nondiabetic patients with OSA are at increased risk of developing insulin resistance and diabetes. These disorders independently contribute to increased cardiovascular and cerebrovascular morbidity and mortality. The pathophysiology of OSA may help explain these associations. Evidence demonstrates that treatment of OSA with continuous positive airway pressure may lead to improvement in insulin sensitivity, hemoglobin A1c, systemic hypertension, and other components of the metabolic syndrome. Recognizing and treating OSA in patients with insulin resistance or diabetes ameliorates OSA-related symptoms and improves cardiometabolic risk.

Active humidification with Boussignac CPAP: in vitro study of a new method

OBJECTIVE

To carry out an in vitro study of Boussignac CPAP valve performance with a new humidification method, using a heated humidifier.

METHODS

Two heated humidifiers were evaluated: Fisher & Paykel MR850, and Covidien Kendall Aerodyne 2000. Baseline measurements were taken in all experimental conditions without humidification. The Boussignac valve was adapted to the input of the humidification chamber. The system was connected to a test lung to assess the degree of pressurization. Hygrometric and pressure measurements were performed with the following gas flows: 10, 20, 30 and 40 L/min.

RESULTS

The mean values of pressure generated by the Boussignac valve were 1.99 ± 0.02, 6.97 ± 0.05, 16.61 ± 0.08 and 21.24 ± 0.08 cm H2O, 10, 20, 30 and 40 L/min, respectively, no differences being detected between study groups. Overall absolute humidity was significantly greater with a heated humidifier than without humidification (range 40.01 ± 0.57-25.46 ± 0.49 compared to 0.16 ± 0.13 mgH2O/L, P < .001). Absolute humidity was significantly higher in Kendall Aerodyne 2000 compared to MR850, regardless of the selected temperature and flow (P < .001).

CONCLUSIONS

This new method of Boussignac CPAP humidification yielded humidity values above 25 mg H2O/L regardless of the heated humidifier and flow used. Pressurization values remained constant in each experimental situation and were not influenced by adding humidification. These data open up the possibility of using Boussignac CPAP on different types of patients, with different interfaces and for long periods of time.

Effect of visualization of raw graphic polysomnography data by sleep apnea patients on adherence to CPAP therapy

BACKGROUND

CPAP is considered to be the cornerstone of therapy for obstructive sleep apnea. However, adherence to this treatment is frequently poor, which may lead to ongoing symptoms, including daytime sleepiness and poor cognitive function. We aimed to determine the efficacy of showing patients their raw graphic polysomnography (PSG) data in increasing their CPAP adherence.

METHODS

The subjects were patients with obstructive sleep apnea (n = 37, diagnosed on prior PSG), who were prospectively randomized into an experimental arm or a control arm. The patients in the experimental arm (n = 18) were shown detailed PSG data, including graphic data from PSG prior to prescription of CPAP. The patients in the control arm (n = 19) were shown the non-graphic paper report of the PSG. Adherence data, collected using CPAP devices with internal microprocessors (adherence cards), was read at 4 weeks after treatment initiation.

RESULTS

There was no difference in age (57.3 ± 11.8 y vs 55.5 ± 11.6 y, P = .64), body mass index (BMI) (32.7 ± 6.3 kg/m(2) vs 32.3 ± 6.6 kg/m(2), P = .85), and apnea-hypopnea index (36.0 ± 27.8 events/h vs 30.5 ± 19.1 events/h, P = .48) between the experimental and control arms. There was no difference in percent of days CPAP was used (58% vs 64%, P = .59) and average number of hours each night CPAP was used (3.9 ± 2.1 h vs 4.1 ± 2.5 h, P = .76) between the experimental and control arms, respectively. In multi logistic regression models, which included age, BMI > 30 kg/m(2), apnea-hypopnea index, and experimental intervention, only BMI was found to increase likelihood of improved adherence (odds ratio = 13.3, P = .007).

CONCLUSIONS

Showing patients raw graphic PSG data does not seem to improve adherence to CPAP. BMI is a very strong predictor of CPAP adherence.

A randomised controlled trial on the effect of mask choice on residual respiratory events with continuous positive airway pressure treatment

INTRODUCTION

It has been found that mask style can affect the amount of continuous positive airway pressure (CPAP) required to reduce an apnoea/hyponoea index (AHI) to < 5/h on a titration study. However, it was not previously known whether switching from one CPAP mask style to another post titration could affect the residual AHI with CPAP. The purpose of this study was to investigate the differences in residual AHI with CPAP treatment between oronasal and nasal masks.

METHODS

Twenty-one subjects (age mean (M)=62.9, body mass index (BMI) M=29.6 kg/m2) were randomised (14 subjects completed the protocol) to undergo an in-laboratory CPAP titration with either a nasal mask or an oronasal mask. Subjects were then assigned this mask for 3weeks of at-home CPAP use with the optimal treatment pressure determined on the laboratory study (CPAP M=8.4 cm of H2O). At the end of this 3-week period, data were collected from the CPAP machine and the subject was given the other mask to use with the same CPAP settings for the next 3weeks at home (if the nasal mask was given initially, the oronasal one was given later and vice versa). On completion of the second 3-week period, data on residual AHI were again collected and compared with the first 3-week period on CPAP.

RESULTS

A Wilcoxon Signed-Rank Test (two-tailed) revealed that residual AHI with CPAP treatment was significantly higher with the oronasal compared with the nasal mask (z = -3.296, p<0.001). All 14 subjects had a higher residual AHI with the oronasal versus nasal mask, and 50% of the subjects had a residual AHI >10/h in the oronasal mask condition, even though all of these subjects were titrated to an AHI of < 5/h in the laboratory.

CONCLUSION

A higher residual AHI was seen in all patients with the use of an oronasal mask compared with a nasal mask. Switching to an oronasal mask post titration results in an increase in residual AHI with CPAP treatment, and pressure adjustment may be warranted.

Asymmetric spindle pole formation in CPAP-depleted mitotic cells

CPAP is an essential component for centriole formation. Here, we report that CPAP is also critical for symmetric spindle pole formation during mitosis. We observed that pericentriolar material between the mitotic spindle poles were asymmetrically distributed in CPAP-depleted cells even with intact numbers of centrioles. The length of procentrioles was slightly reduced by CPAP depletion, but the length of mother centrioles was not affected. Surprisingly, the young mother centrioles of the CPAP-depleted cells are not fully matured, as evidenced by the absence of distal and subdistal appendage proteins. We propose that the selective absence of centriolar appendages at the young mother centrioles may be responsible for asymmetric spindle pole formation in CPAP-depleted cells. Our results suggest that the neural stem cells with CPAP mutations might form asymmetric spindle poles, which results in premature initiation of differentiation.

Positive distending pressure produced by heated, humidified high flow nasal cannula as compared to nasal continuous positive airway pressure in premature infants

OBJECTIVE

our objective is to assess the positive distending pressure generated by high flow nasal cannula and nasal continuous positive airway pressure by measuring the end esophageal pressure in premature infants.

STUDY DESIGN

This is a pilot, non-randomized, open label, uncontrolled, crossover assignment study that included neonates born with a birth weight of 1750 grams or less and receiving nCPAP ventilatory support for 24 hrs or more and requiring FiO2 21-50% on nCPAP. Each infant was started on nCPAP at 4, 6 and 8 cm H2O then on three levels of HHHFNC, 4 L/min, 6 L/min and 8 L/min with 4 hours interval on each flow level. Esophageal pressure (EP), apnea of prematurity, FiO2 requirements and bradycardia were recorded during the different levels of CPAP and HHHFNC use.

RESULTS

The study showed that there were no complications observed during the study such as pneumothorax. It showed that EP created by the three different levels of HHHFNC were slightly higher than that EPs created by the three different levels of nCPAP, but statistically not significant. There was no significant change in the FiO2 requirements during the study. There was a trend towards the improvement of oxygen saturation in HHHFNC at different levels and it was statistically significant when 8 L/min was used (P 0.0214). The rates of bradycardia and apnea in nCPAP and HHHFNC were low and statistically were not significant, however the episodes of bradycardia were less in HHHFNC and they were statistically significant at the level of 6 L/min.

CONCLUSIONS

HHHFNC in premature infants was well-tolerated with no adverse side effects such as pneumothorax, desaturation, apnea and bradycardia. The study also showed that HHHFNC was able to deliver distending pressure equal to nCPAP. Moreover, we have observed a significant improvement in oxygen saturation when higher levels of HHHFNC was used, most probably due to the improvement of infant comfort which is a noticeable feature of HHHFNC.

Estimation of parasympathetic nerve function during sleep in patients with obstructive sleep apnea by instantaneous time-frequency analysis

BACKGROUND AND OBJECTIVES

The pathophysiologic aspects of parasympathetic nerve (PN) function during sleep in patients with obstructive sleep apnea (OSA) studied by classical power spectrum analysis on heart rate variability (HRV) are highly controversial. The controversy is attributed to methodologic concerns, such as poor time resolution involved in power spectrum analysis. We aimed to establish the appropriate method for the investigation of PN function in OSA patients with apneas and hypopneas using instantaneous time-frequency analysis with complex demodulation (CD) and sufficient time resolution.

METHODS

A total of 30 patients with PSG-confirmed mild to severe OSA were recruited for the analysis of frequency spectra contained in R-R intervals (RRI) of overnight electrocardiograph (ECG) tracings. High-frequency (HF) domains ranging between 0.15 and 0.40 Hz were selected for analysis. Among these domains, the HF domain with the maximum instantaneous amplitude was defined as the main HF peak and was used as the surrogate marker of PN discharge. Based on density spectrum array (DSA) map for main HF peak constructed with a time scale of 1s and a frequency resolution of 0.002 Hz (HF-DSA map), the shift in central frequency (CF) of main HF peak over time was continuously monitored. When the main HF peak with the same CF lasted for more than 20 s or 5 min on HF-DSA map, the PN function was considered to be stable or very stable. The measurements were then repeated after continuous positive airway pressure (CPAP) treatment.

RESULTS

The extent of PN-evoked modulation of RRI was enhanced in nonrapid eye movement (NREM) sleep, though the stability was reduced in both NREM and rapid eye movement (REM) sleep. These peculiar behaviors of PN function were reversed by CPAP treatment.

CONCLUSION

We found that instantaneous time-frequency analysis allowed estimation of transitional changes in PN function during sleep in OSA patients.

Intubation in the delivery room: experience with nasal midazolam

BACKGROUND

Neonates are often intubated in the delivery room (DR) without anesthesia because vascular access is impossible.

AIMS

To assess neonatal comfort and adverse events after use of nasal midazolam (nMDZ) for intubation in the DR.

STUDY DESIGN

Prospective data collection over 6months on the intubation of neonates with respiratory distress requiring tracheal instillation of surfactant.

SUBJECTS

Twenty-seven neonates with median (Q25-75) gestational age and birthweight of, respectively, 29 (27-33)weeks and 1270 (817-1942)g received a 0.1mg/kg dose of nMDZ, and intubation was performed at the onset of tonus resolution or apnea.

OUTCOME MEASURES

Comfort was assessed with a scale of hetero-pain assessment and electrical skin conductance monitoring. Continuous pulse oximetry was recorded in the first postnatal hour, with oscillometric blood pressure measurement every 10min.

RESULTS

Seventy percent of the patients required a single dose, with intubation performed 4.8 (3-9)min after administration. Combined electro-clinical assessment found adequate comfort during the procedure in 68% of neonates. Mean blood pressure decreased from 39 (34-44)mmHg before to 31 (25-33)mmHg 1h following nMDZ (p=0.011).

CONCLUSION

nMDZ provided rapid and effective sedation to intubate neonates in the DR but potentially exposed them to hypotension, thus requiring close hemodynamic monitoring.

Alternobaric vertigo in a patient on positive airway pressure therapy

Continuous positive airway pressure (CPAP) is a safe therapy for the management of obstructive sleep apnea (OSA). Complications such as sinus infection, bronchitis, ear pain, nasal congestion, and dryness of mucous membranes secondary to CPAP use have been reported. To follow, we describe a rare case of alternobaric vertigo secondary to CPAP therapy. To date, there has been only one reported case of hearing loss and vertigo during CPAP treatment with complete resolution of symptoms after cessation of PAP. However, re-challenging the patient with CPAP at gradual increments was never reported.

Management of obstructive sleep apnea in the indigent population: a deviation of standard of care?

Comprehensive management of patients with obstructive sleep apnea (OSA) typically is managed best via a multidisciplinary approach, involving otolaryngologists, sleep psychologists/psychiatrists, pulmonologists, neurologists, oral surgeons, and sleep trained dentists. By utilizing these resources, one could fashion a treatment individualized to the patient, giving rise to the holistic phrase of "personalized medicine." Unfortunately, in situations and environments with limited resources, the treatment options in an otolaryngologist's armamentarium are restricted--typically to continuous positive airway pressure (CPAP) versus sleep surgery. However, a recent patient encounter highlighted here shows how a hospital's reimbursement policy effectively dictated a patient's medical management to sleep surgery. This occurred although the current gold standard for the initial treatment of OSA is CPAP. Changing the course of medical/surgical management by selectively restricting funding is a cause of concern, especially when it promotes patients to choose a treatment option that is not considered the current standard of care.

Prevalence of head deformities in preterm infants at term equivalent age

INTRODUCTION

Due to a rising number of head deformities in healthy newborns, there has been an increasing interest in nonsynostotic head deformities in children over recent years. Although preterm infants are more likely to have anomalous head shapes than term newborns, there is limited data available on early prevalence of head deformities in preterm infants.

AIMS

The purposes of the present study were to acquire quantitative data on head shape of preterm infants at Term Equivalent Age (TEA), to determine the prevalence of symmetrical and asymmetrical head deformities and to identify possible risk factors.

METHODS

In a cross-sectional study design, Cranial Vault Asymmetry Index (CVAI) and Cranial Index (CI) calculated from routine head-scans with a non-invasive laser shape digitizer were recorded and categorized in type and severity of deformation for three different groups of gestational age. Perinatal and postnatal patient data was tested for possible associations.

RESULTS

Scans of 195 infants were included in the study. CVAI at TEA was higher in very preterm (4.1%) compared to term and late preterm infants. Prevalence of deformational plagiocephaly was 38% in very preterm infants. CI was lower in very (71.4%) and late (77.2%) preterm infants compared to term infants (80.0%). Compared to term babies (11%), a large number of very (73%) and late (28%) preterm infants exhibited dolichocephaly at TEA.

DISCUSSION

Prevalence of symmetrical and asymmetrical head deformities in preterm infants is high at TEA. Interventions are required to prevent head deformities in preterm infants during the initial hospital stay.

Symptoms of insomnia among patients with obstructive sleep apnea before and after two years of positive airway pressure treatment

STUDY OBJECTIVES

To assess the changes of insomnia symptoms among patients with obstructive sleep apnea (OSA) from starting treatment with positive airway pressure (PAP) to a 2-y follow-up.

DESIGN

Longitudinal cohort study.

SETTING

Landspitali--The National University Hospital of Iceland.

PARTICIPANTS

There were 705 adults with OSA who were assessed prior to and 2 y after starting PAP treatment.

INTERVENTION

PAP treatment for OSA.

MEASUREMENTS AND RESULTS

All patients underwent a medical examination along with a type 3 sleep study and answered questionnaires on health and sleep before and 2 y after starting PAP treatment. The change in prevalence of insomnia symptoms by subtype was assessed by questionnaire and compared between individuals who were using or not using PAP at follow-up. Symptoms of middle insomnia were most common at baseline and improved significantly among patients using PAP (from 59.4% to 30.7%, P < 0.001). Symptoms of initial insomnia tended to persist regardless of PAP treatment, and symptoms of late insomnia were more likely to improve among patients not using PAP. Patients with symptoms of initial and late insomnia at baseline were less likely to adhere to PAP (odds ratio [OR] 0.56, P = 0.007, and OR 0.53, P < 0.001, respectively).

CONCLUSION

Positive airway pressure treatment significantly reduced symptoms of middle insomnia. Symptoms of initial and late insomnia, however, tended to persist regardless of positive airway pressure treatment and had a negative effect on adherence. Targeted treatment for insomnia may be beneficial for patients with obstructive sleep apnea comorbid with insomnia and has the potential to positively affect adherence to positive airway pressure.

CPAP-induced mania in bipolar disorder: a case report

OBJECTIVE

In this case report we present our clinical observations of two patients with bipolar disorder with comorbid obstructive sleep apnea (OSA) who were treated with continuous positive airway pressure (CPAP) for their sleep apnea.

BACKGROUND

Bipolar disorder is a psychiatric disorder characterized by the presence of one or more episodes of mania and frequent episodes of depression. This disorder affects approximately 0.8% of the adult population, with estimates from community samples ranging between 0.4% and 1.6%. OSA syndrome is a severe sleep disorder with a prevalence of 2-4% in the general population, the risk of which is increased by obesity. The prevalence of OSA is expected to be high in bipolar disorder due to high comorbid obesity. It is expected that improvement in OSA in patients with bipolar disorder with CPAP will improve mood and other symptoms of bipolar disorder. However, there is a relative lack of data examining this aspect.

RESULTS

In both cases of bipolar disorder, CPAP was started after a polysomnographic diagnosis of OSA and CPAP titration study indicating that most of the apneas/hypopneas were eliminated with a significant improvement in oxygen saturation. To our surprise, we noted that in both of these cases initiation of CPAP resulted in manic symptoms.

CONCLUSIONS

Clinicians need to monitor patients with bipolar disorder closely for worsening of manic symptoms when they are started on CPAP for underlying OSA.

ALG1-CDG: a new case with early fatal outcome

Congenital disorders of glycosylation (CDG) are a growing group of inherited metabolic disorders where enzymatic defects in the formation or processing of glycolipids and/or glycoproteins lead to variety of different diseases. The deficiency of GDP-Man:GlcNAc2-PP-dolichol mannosyltransferase, encoded by the human ortholog of ALG1 from yeast, is known as ALG1-CDG (CDG-Ik). The phenotypical, molecular and biochemical analysis of a severely affected ALG1-CDG patient is the focus of this paper. The patient's main symptoms were feeding problems and diarrhea, profound hypoproteinemia with massive ascites, muscular hypertonia, seizures refractory to treatment, recurrent episodes of apnoea, cardiac and hepatic involvement and coagulation anomalies. Compound heterozygosity for the mutations c.1145T>C (M382T) and c.1312C>T (R438W) was detected in the patient's ALG1-coding sequence. In contrast to a previously reported speculation on R438W we confirmed both mutations as disease-causing in ALG1-CDG.

Medicare long-term CPAP coverage policy: a cost-utility analysis

STUDY OBJECTIVES

CPAP is an effective treatment for OSA that may reduce health care utilization and costs. Medicare currently reimburses the costs of long-term CPAP therapy only if the patient is adherent during a 90-day trial. If not, Medicare requires a repeat polysomnogram (PSG) and another trial which seems empirically not cost-effective. We modeled the cost-effectiveness of current Medicare policy compared to an alternative policy (clinic-only) without the adherence criterion and repeat PSG.

DESIGN

Cost-utility and cost-effectiveness analysis.

SETTING

U.S. Medicare Population.

PATIENTS OR PARTICIPANTS

N/A.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

We created a decision tree modeling (1) clinic only follow-up vs. (2) current Medicare policy. Costs were assigned based on Medicare reimbursement rates in 2012. Sensitivity analyses were conducted to test our assumptions. We estimated cumulative costs, overall adherence, and QALY gained for a 5-year time horizon from the perspective of Medicare as the payer. Current Medicare policy is more costly than the clinic-only policy but has higher net adherence and improved utility. Current Medicare policy compared to clinic-only policy costs $30,544 more per QALY.

CONCLUSIONS

Current CMS policy promotes early identification of those more likely to adhere to CPAP therapy by requiring strict adherence standards. The policy effect is to deny coverage to those unlikely to use CPAP long-term and prevent wasted resources. Future studies are needed to measure long-term adherence in an elderly population with and without current adherence requirements to verify the cost-effectiveness of a policy change.

Continuous positive airway pressure and noninvasive ventilation adherence in children

BACKGROUND

Adherence to continuous positive airway pressure (CPAP) and noninvasive ventilation (NIV) is crucial for the successful treatment of sleep-disordered breathing. The aim of our study was to analyze the adherence of children to long-term home CPAP/NIV treatment.

METHODS

We analyzed data from all consecutive patients older than the age of 2years, in whom CPAP/NIV treatment was initiated in a specialized pediatric NIV and in those who were receiving CPAP/NIV treatment at home for at least 1month. Data of the memory cards of the ventilators and nocturnal gas exchange were analyzed during a routine CPAP/NIV overnight control in the hospital. CPAP/NIV adherence during the previous month was analyzed according to patient's age, ventilatory mode, type of interface, nocturnal gas exchange, and duration of treatment.

RESULTS

The data of 62 children (mean age, 10±5years) with obstructive sleep apnea (n=51) treated with CPAP and neuromuscular disease (n=6) or lung diseases (n=5) treated with NIV were analyzed. Mean adherence was 8:17±2:30h:min per night, and the results did not significantly differ between CPAP and NIV adherence. Seventy-two percent of the patients used their device >8h per night. The mean number of nights of CPAP/NIV use during the last month was 26±5 nights per month. Treatment adherence was not correlated to age, the type of underlying disease, the type of interface (nasal, facial mask, or nasal cannula), nocturnal gas exchange, and duration of CPAP/NIV treatment.

CONCLUSION

Long-term CPAP/NIV adherence at home was extremely high in this group of children followed in a pediatric NIV unit. This finding may explain the lack of effect of the interface, nocturnal gas exchange, and duration of CPAP/NIV treatment.

Crystal structures of the CPAP/STIL complex reveal its role in centriole assembly and human microcephaly

Centrioles organise centrosomes and template cilia and flagella. Several centriole and centrosome proteins have been linked to microcephaly (MCPH), a neuro-developmental disease associated with small brain size. CPAP (MCPH6) and STIL (MCPH7) are required for centriole assembly, but it is unclear how mutations in them lead to microcephaly. We show that the TCP domain of CPAP constitutes a novel proline recognition domain that forms a 1:1 complex with a short, highly conserved target motif in STIL. Crystal structures of this complex reveal an unusual, all-β structure adopted by the TCP domain and explain how a microcephaly mutation in CPAP compromises complex formation. Through point mutations, we demonstrate that complex formation is essential for centriole duplication in vivo. Our studies provide the first structural insight into how the malfunction of centriole proteins results in human disease and also reveal that the CPAP–STIL interaction constitutes a conserved key step in centriole biogenesis.

DOI:http://dx.doi.org/10.7554/eLife.01071.001

Organisms—and individual tissues—grow and develop by dividing their cells. However, the process of cell division does not have to be symmetric, and the fates of the cells can be very different if cellular contents, including RNAs or proteins, are exclusively retained in the ‘mother’ or passed to her ‘daughter’. Organelles known as centrioles can play an important part in influencing whether cell division is symmetric or asymmetric.

Centrioles contain ordered assemblies of various proteins, and mutations in some of these proteins can cause developmental defects in humans. For example, mutations in the centriolar proteins CPAP and STIL cause a syndrome known as microcephaly, in which the brain is smaller than normal. Although CPAP and STIL are known to bind each other, how they interact on a molecular level to form centrioles—and how this interaction is disrupted in microcephaly—is not well understood.

Cottee et al. have now used structural and biochemical assays to explore how these two proteins bind to each other, and have identified specific amino acid residues that enable this interaction. These residues are highly conserved across many organisms, and a mutation in one of them has previously been associated with microcephaly in humans. Now, Cottee et al. demonstrate that this mutation weakens the interaction between CPAP and STIL in vitro.

To explore these processes in vivo, Cottee et al. studied mutant fruit flies in which the interactions between CPAP and STIL were weaker than normal, and found that these mutations prevented the normal formation of centrioles. Furthermore, there was a striking correlation between the ability to form centrioles in fruit flies and the ability of CPAP and STIL to bind each other, based on the structural model and in vitro binding studies.

Cumulatively, these findings reinforce the importance of CPAP and STIL in centriole formation, and suggest that one reason for the development of microcephaly may be defects in the proper formation of centrioles.

DOI:http://dx.doi.org/10.7554/eLife.01071.002

An integrative review of skin breakdown in the preterm infant associated with nasal continuous positive airway pressure

OBJECTIVE

To identify factors associated with skin injury during nasal continuous positive airway pressure (NCPAP) and describe differences in frequency, severity, and type of skin injuries when comparing nasal interfaces used during NCPAP in the preterm infant.

DATA SOURCES

Scientific databases were searched using provided key terms and yielded 113 articles.

STUDY SELECTION

Forty-six articles were included in this integrative review: six case studies, 22 with identified aim of examining skin and nasal injury during NCPAP; 18 included skin care considerations during NCPAP.

DATA EXTRACTION

Studies were categorized into four themes: types of nasal injuries; associated risk factors that increase incidence of injury; differences between NCPAP devices and/or nasal interface and corresponding rate and severity of nasal injury; and recommended prevention strategies to reduce iatrogenic cutaneous injury.

DATA SYNTHESIS

Skin injury was a common theme during neonatal NCPAP with skin breakdown rates of 20% to 60%. Increased skin injury risk was associated with smaller infant size, gestational age, and duration of therapy. Nursing care strategies to improve skin integrity during NCPAP had little supportive evidence. Nursing practice is varied with reportedly little standardized care during NCPAP therapy. Recommendations for specific care strategies to reduce skin injury during NCPAP were supported by limited experimental studies.

CONCLUSIONS

Risk factors during NCPAP include nasal injury and trauma secondary to tight-fitting nasal interfaces necessary to provide continuous distending pressure for respiratory stability. Identifying strategies to reduce skin breakdown will support noninvasive treatment success, reduce reintubation rates, reduce sepsis, reduce patient discomfort, and improve developmental outcomes during NCPAP use.

Review of clinical presentation and diagnosis of mucopolysaccharidosis IVA

Mucopolysaccharidosis type IVA (MPS IVA) was described in 1929 by Luis Morquio from Uruguay and James Brailsford from England, and was later found as an autosomal recessive lysosomal storage disease. MPS IVA is caused by mutations in the gene encoding the enzyme, N-acetylgalactosamine-6-sulfate sulfatase (GALNS). Reduced GALNS activity results in impaired catabolism of two glycosaminoglycans (GAGs), chondroitin-6-sulfate (C6S) and keratan sulfate (KS). Clinical presentations of MPS IVA reflect a spectrum of progression from a severe "classical" phenotype to a mild "attenuated" phenotype. More than 180 different mutations have been identified in the GALNS gene, which likely explains the phenotypic heterogeneity of the disorder. Accumulation of C6S and KS manifests predominantly as short stature and skeletal dysplasia (dysostosis multiplex), including atlantoaxial instability and cervical cord compression. However, abnormalities in the visual, auditory, cardiovascular, and respiratory systems can also affect individuals with MPS IVA. Diagnosis is typically based on clinical examination, skeletal radiographs, urinary GAG, and enzymatic activity of GALNS in blood cells or fibroblasts. Deficiency of GALNS activity is a common assessment for the laboratory diagnosis of MPS IVA; however, with recently increased availability, gene sequencing for MPS IVA is often used to confirm enzyme results. As multiple clinical presentations are observed, diagnosis of MPS IVA may require multi-system considerations. This review provides a history of defining MPS IVA and how the understanding of the disease manifestations has changed over time. A summary of the accumulated knowledge is presented, including information from the International Morquio Registry. The classical phenotype is contrasted with attenuated cases, which are now being recognized and diagnosed more frequently. Laboratory based diagnoses of MPS IVA are also discussed.

Nocturnal mouthpiece ventilation and medical hypnosis to treat severe obstructive sleep apnea in a child with cherubism

A 4-year old boy presented severe obstructive sleep apnoea due to complete nasal obstruction secondary to cherubism. Because of anticipatory anxiety due to numerous surgical interventions, medical hypnosis was proposed to facilitate non-invasive continuous positive pressure ventilation (CPAP) acceptance. CPAP by means of an oral interface was completely accepted after three hypnosis sessions and resulted in the correction of his obstructive sleep apnea (OSA) syndrome. This report highlights the benefit of medical hypnosis in facilitating CPAP acceptance as well as the efficacy of mouthpiece ventilation in a severe form of cherubism with complete nasal obstruction.

Whole blood hypoxia-related gene expression reveals novel pathways to obstructive sleep apnea in humans

In this study, our goal was to identify the key genes that are associated with obstructive sleep apnea (OSA). Thirty-five volunteers underwent full in-lab polysomnography and, according to the sleep apnea hypopnea index (AHI), were classified into control, mild-to-moderate OSA and severe OSA groups. Severe OSA patients were assigned to participate in a continuous positive airway pressure (CPAP) protocol for 6 months. Blood was collected and the expression of 84 genes analyzed using the RT(2) Profiler™ PCR array. Mild-to-moderate OSA patients demonstrated down-regulation of 2 genes associated with induction of apoptosis, while a total of 13 genes were identified in severe OSA patients. After controlling for body mass index, PRPF40A and PLOD3 gene expressions were strongly and independently associated with AHI scores. This research protocol highlights a number of molecular targets that might help the development of novel therapeutic strategies.

Association of CPAP bacterial colonization with chronic rhinosinusitis

STUDY OBJECTIVE

The purpose of our study was to investigate whether bacterial colonization of the continuous positive air-way pressure (CPAP) machine reservoirs occurred, and if so, if it was related to the development of chronic rhinosinusitis (CRS).

DESIGN

Prospective cohort study.

SETTING

London Health Sciences Center (LHSC).

PATIENTS

Regular CPAP users with obstructive sleep apnea (OSA).

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Patient demographics were recorded and they were asked to fill out the chronic sinusitis survey (CSS) form. Patients then had their CPAP machines swabbed. An ANOVA was used to determine if the presence of microbacterial colonization was related to CSS scores. In total, 72 patients were included in the study. There was no significant difference in any of the scores between the group with positive cultures and the group without positive cultures.

CONCLUSIONS

Having a positive culture in the cpap reservoir does not seem to lead to an increased symptomatology of crs: although the reservoirs often become colonized, there seems to be no clinical impact.

Marked variation in delivery room management in very preterm infants

Background

The International Liaison Committee on Resuscitation (ILCOR) and UK Resuscitation Council (UKRC) updated guidance on newborn resuscitation in late 2010.

Objectives

To describe delivery room (DR) practice in stabilisation following very preterm birth (<32 weeks gestation) in the UK.

Methods

We emailed a national survey of current DR stabilisation practice of very preterm infants to all UK delivery units and conducted telephone follow-up calls.

Results

We obtained 197 responses from 199 units (99%) and complete data from 186 units. Tertiary units administered surfactant in the DR (93% vs. 78%, P = 0.01), instituted DR CPAP (77% vs. 50%, P = 0.0007), provided PEEP in the delivery room (91% vs. 69%, P = 0.0008), and started resuscitation in air or blended oxygen (91% vs. 78%, P = 0.04) more often than non-tertiary units. Routine out of hours consultant attendance at very preterm birth was more common in tertiary units (82% vs. 55%, P = 0.0005).

Conclusions

Marked variation in DR stabilisation practice of very preterm infants persisted one year after the publication of revised UKRC guidance. Delivery room care provided in non-tertiary units was less consistent with current international guidance.

Polysomnograph chart view by patients: a new educational strategy to improve CPAP adherence in sleep apnea therapy

BACKGROUND

CPAP is currently the treatment of choice for obstructive sleep apnea syndrome, but therapy adherence is poor. Many educational trials have been proposed to increase CPAP adherence. We tested the hypothesis that polysomnograph chart viewing by patients would improve CPAP adherence.

METHODS

A controlled parallel group study was performed with 206 newly diagnosed obstructive sleep apnea syndrome patients, randomized into 2 groups (n = 103 each): standard support group, and educational support group. Each educational support group subject viewed 2 consecutive polysomnograms on the computer screen: the first recorded during a standard diagnostic overnight polysomnography, and the second during a full-night polysomnography with nasal CPAP. The subject's attention was drawn only to the flow and oxyhemoglobin saturation curves. Clinical outcomes were assessed via polysomnography at CPAP initiation and after 1, 3, and 12 months.

RESULTS

After 12 months of CPAP, 76% of the educational support group and 52% of the standard support group returned for a follow-up visit (P < .001). Statistical significance had already been reached after 1 and 3 months. Moreover, CPAP use (measured as hours of use per night) was higher in the educational support group at each control visit.

CONCLUSIONS

Polysomnograph chart viewing by obstructive sleep apnea patients can increase CPAP adherence, as evaluated by rate of return for the follow-up visit and mean nightly CPAP use.

Randomized controlled trial of noninvasive positive pressure ventilation (NPPV) versus servoventilation in patients with CPAP-induced central sleep apnea (complex sleep apnea)

STUDY OBJECTIVES

To compare the treatment effect of noninvasive positive pressure ventilation (NPPV) and anticyclic servoventilation in patients with continuous positive airway pressure (CPAP)-induced central sleep apnea (complex sleep apnea).

DESIGN

Randomized controlled trial.

SETTING

Sleep center.

PATIENTS

Thirty patients who developed complex sleep apnea syndrome (CompSAS) during CPAP treatment.

INTERVENTIONS

NPPV or servoventilation.

MEASUREMENTS AND RESULTS

Patients were randomized to NPPV or servo-ventilation. Full polysomnography (PSG) was performed after 6 weeks. On CPAP prior to randomization, patients in the NPPV and servoventilator arm had comparable apnea-hypopnea indices (AHI, 28.6 ± 6.5 versus 27.7 ± 9.7 events/h (mean ± standard deviation [SD])), apnea indices (AI,19 ± 5.6 versus 21.1 ± 8.6 events/h), central apnea indices (CAI, 16.7 ± 5.4 versus 18.2 ± 7.1 events/h), oxygen desaturation indices (ODI,17.5 ± 13.1 versus 24.3 ± 11.9 events/h). During initial titration NPPV and servoventilation significantly improved the AHI (9.1 ± 4.3 versus 9 ± 6.4 events/h), AI (2 ± 3.1 versus 3.5 ± 4.5 events/h) CAI (2 ± 3.1 versus 2.5 ± 3.9 events/h) and ODI (10.1 ± 4.5 versus 8.9 ± 8.4 events/h) when compared to CPAP treatment (all P < 0.05). After 6 weeks we observed the following differences: AHI (16.5 ± 8 versus 7.4 ± 4.2 events/h, P = 0.027), AI (10.4 ± 5.9 versus 1.7 ± 1.9 events/h, P = 0.001), CAI (10.2 ± 5.1 versus 1.5 ± 1.7 events/h, P < 0.0001)) and ODI (21.1 ± 9.2 versus 4.8 ± 3.4 events/h, P < 0.0001) for NPPV and servoventilation, respectively. Other sleep parameters were unaffected by any form of treatment.

CONCLUSIONS

After 6 weeks, servoventilation treated respiratory events more effectively than NPPV in patients with complex sleep apnea syndrome.

Effects of changes in energy homeostasis and exposure of noxious insults on the expression of orexin (hypocretin) and its receptors in the brain

This review summarizes data regarding the brain expression of the orexin (hypocretin) system including: prepro-orexin (PPO), orexin A (OxA), orexin B (OxB) and the two orexin receptors 1 and 2 (OxR1, OxR2). Clinical data is limited to OxA and OxB in cerebral spinal fluid and serum/plasma, thus necessitating the development of animal models to undertake mechanistic studies. We focus on changes in animal models that were either exposed to a regime of altered sleep, metabolic energy homeostasis, exposed to drugs and noxious insults. Many more expressional studies are available for PPO, OxA and OxB levels, compared to studies of the receptors. Interestingly, the direction and pattern of change for PPO, OxA and OxB is inconsistent amongst studies, whereas for the receptors, there tends to be increased expression for both OxR1 and OxR2 after alterations in energy homeostasis, and an increased expression after noxious insults or exposure to some drugs. The clinical implications of these results from animal models are discussed in light of the findings from human studies, and future research directions are suggested to fill knowledge gaps with regard to the orexin system, particularly during early brain development.

Investigation and management of childhood sleep apnoea

Sleep-disordered breathing includes disorders of breathing that affect airway patency, e.g. obstructive sleep apnoea syndrome, and also conditions that affect respiratory drive (central sleep disorders) or cause hypoventilation, either as a direct central effect or due to peripheral muscle weakness. Obstructive sleep apnoea syndrome (OSAS) is an increasingly-recognised clinical entity affecting up to 5.7% of children, which, if left untreated, is associated with adverse effects on growth and development including deleterious cognitive and behavioural outcomes. Evidence exists also that untreated OSAS impacts on cardiovascular risk. Close attention should be paid to assessment and investigation of this relatively common condition, instigating early and appropriate treatment to children with OSAS. First-line treatment in younger children is adenotonsillectomy, although other treatment options available include continuous positive airways pressure (CPAP), anti-inflammatory therapies (nasal corticosteroids and anti-leukotrienes), airway adjuncts and orthodontic appliances. Central sleep-disordered breathing may be related to immaturity of respiratory control and can be associated with prematurity as well as disorders such as Prader-Willi syndrome. In some cases, central apnoeas occur as part of a central hypoventilation disorder, which may be inherited, e.g. Congenital Central hypoventilation Syndrome, or acquired, e.g. Arnold-Chiari malformation, brain tumour, or spinal injury. The treatments of central breathing problems depend upon the underlying aetiology.

Impact of group education on continuous positive airway pressure adherence

STUDY OBJECTIVES

To compare the impact of a group educational program versus individual education on continuous positive airway pressure (CPAP) adherence.

METHODS

Post hoc assessment of a performance improvement initiative designed to improve clinic efficiency, access to care, and time to initiate therapy. Consecutive patients newly diagnosed with obstructive sleep apnea (OSA) initiating CPAP therapy participated in either an individual or group educational program. The content and information was similar in both strategies.

RESULTS

Of 2,116 included patients, 1,032 received education regarding OSA and CPAP through a group clinic, and 1,084 received individual education. Among the cohort, 76.6% were men, mean age 48.3 ± 9.2 years, mean body mass index 29.6 ± 4.6 kg/m(2), and mean apnea-hypopnea index was 33.3 ± 24.4 events/hour. Baseline characteristics were similar between groups. CPAP adherence was significantly greater in those participating in a group program than those receiving individual education. Specifically, CPAP was used for more nights (67.2% vs. 62.1%, p = 0.02) and more hours per night during nights used (4.3 ± 2.1 vs. 3.7 ± 2.8, p = 0.03). Further, fewer individuals discontinued therapy (10.6% vs. 14.5%, p < 0.001), more achieved regular use of CPAP (45.2%. vs. 40.6%, p = 0.08), and time to initiate therapy was shorter (13.2 ± 3.1 versus 24.6 ± 7.4 days, p < 0.001). Group education resulted in a 3- to 4-fold increase in the number of patients seen per unit time.

CONCLUSIONS

A group educational program facilitated improved CPAP adherence. If confirmed by prospective randomized studies, group CPAP education may be an appropriate alternative to individual counseling, may improve acceptance of and adherence to therapy, and decrease time to treatment.

Obstructive sleep apnea: a cardiometabolic risk in obesity and the metabolic syndrome. J Am Coll Cardiol. 2013;62:569-576. [PMID: 23770180 DOI: 10.1016/j.jacc.2013.05.045]

Obstructive sleep apnea (OSA) is an underdiagnosed condition characterized by recurrent episodes of obstruction of the upper airway leading to sleep fragmentation and intermittent hypoxia during sleep. Obesity predisposes to OSA, and the prevalence of OSA is increasing worldwide because of the ongoing epidemic of obesity. Recent evidence has shown that surrogate markers of cardiovascular risk, including sympathetic activation, systemic inflammation, and endothelial dysfunction, are significantly increased in obese patients with OSA versus those without OSA, suggesting that OSA is not simply an epiphenomenon of obesity. Moreover, findings from animal models and patients with OSA show that intermittent hypoxia exacerbates the metabolic dysfunction of obesity, augmenting insulin resistance and nonalcoholic fatty liver disease. In patients with the metabolic syndrome, the prevalence of moderate to severe OSA is very high (∼60%). In this population, OSA is independently associated with increased glucose and triglyceride levels as well as markers of inflammation, arterial stiffness, and atherosclerosis. A recent randomized, controlled, crossover study showed that effective treatment of OSA with continuous positive airway pressure for 3 months significantly reduced several components of the metabolic syndrome, including blood pressure, triglyceride levels, and visceral fat. Finally, several cohort studies have consistently shown that OSA is associated with increased cardiovascular mortality, independent of obesity. Taken together, these results support the concept that OSA exacerbates the cardiometabolic risk attributed to obesity and the metabolic syndrome. Recognition and treatment of OSA may decrease the cardiovascular risk in obese patients.

Effects of armodafinil on simulated driving and self-report measures in obstructive sleep apnea patients prior to treatment with continuous positive airway pressure

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) has been associated with an increased risk of motor vehicle crashes. This driving risk can be reduced (≥ 50%) by treatment with continuous positive airway pressure (CPAP). However residual excessive daytime sleepiness (EDS) can persist for some patients who regularly use CPAP. The current study was designed to assess the effect of armodafinil on simulated driving performance and subsequent CPAP treatment compliance in newly diagnosed OSA patients with EDS during a 2-week "waiting period" prior to initiation of CPAP.

METHODS

Sixty-nine newly diagnosed OSA patients, awaiting CPAP therapy, were randomized (1:1) to placebo or armodafinil (150 mg/day) treatment. Simulated driving tests and self-report measures were completed at baseline, after 2 weeks of drug treatment, and following 6 weeks of CPAP treatment. CPAP compliance was evaluated at the end of 6 weeks of CPAP.

RESULTS

Compared to placebo, armodafinil improved simulated driving safety performance in OSA patients awaiting CPAP therapy (p = 0.03). Improvement was seen in lane position deviation (p = 0.002) and number of lane excursions (p = 0.02). Improvement was also observed on measures of sleepiness using the Epworth Sleepiness Scale (ESS) and sleep related quality of life. Following 6 weeks of CPAP, there was also significant improvement observed on multiple measures of simulated driving performance. CPAP compliance did not differ between armodafinil-treated and placebo-treated patients (p = 0.80).

CONCLUSIONS

Armodafinil was found to improve simulated driving performance in OSA patients with EDS prior to initiation of CPAP. Treatment with armodafinil showed no effect on subsequent CPAP compliance.

Evaluation of lung function and deposition of aerosolized bronchodilators carried by heliox associated with positive expiratory pressure in stable asthmatics: a randomized clinical trial

While administration of medical aerosols with heliox and positive airway pressure are both used clinically to improve aerosol delivery, few studies have differentiated their separate roles in treatment of asthmatics. The aim of this randomized, double blinded study is to differentiate the effect of heliox and oxygen with and without positive expiratory pressure (PEP), on delivery of radiotagged inhaled bronchodilators on pulmonary function and deposition in asthmatics. 32 patients between 18 and 65 years of age diagnosed with stable moderate to severe asthma were randomly assigned into four groups: (1) Heliox + PEP (n = 6), (2) Oxygen + PEP (n = 6), (3) Heliox (n = 11) and (4) Oxygen without PEP (n = 9). Each group received 1 mg of fenoterol and 2 mg of ipratropium bromide combined with 25 mCi (955 Mbq) of Technetium-99m and 0.9% saline to a total dose volume of 3 mL placed in a Venticis II nebulizer attached to a closed, valved mask with PEP of 0 or 10 cm H2O. Both gas type and PEP level were blinded to the investigators. Images were acquired with a single-head scintillation camera with the longitudinal and transverse division of the right lung as regions of interest (ROIs). While all groups responded to bronchodilators, only group 1 showed increase in FEV1%predicted and IC compared to the other groups (p < 0.04). When evaluating the ROI in the vertical gradient we observed higher deposition in the middle and lower third in groups 1 (p = 0.02) and 2 (p = 0.01) compared to group 3. In the horizontal gradient, a higher deposition in the central region in groups 1 (p = 0.03) and 2 (p = 0.02) compared to group 3 and intermediate region of group 2 compared to group 3. We conclude that aerosol deposition was higher in groups with PEP independent of gas used, while bronchodilator response with Heliox + PEP improved FEV1 % and IC compared to administration with Oxygen, Oxygen with PEP and Heliox alone. Trial registration NCT01268462.

Heated, humidified high-flow nasal cannula versus nasal CPAP for respiratory support in neonates

BACKGROUND AND OBJECTIVE

Heated, humidified high-flow nasal cannula (HHHFNC) is commonly used as a noninvasive mode of respiratory support in the NICU. The safety and efficacy of HHHFNC have not been compared with other modes of noninvasive support in large randomized trials. The objective was to assess the efficacy and safety of HHHFNC compared with nasal continuous positive airway pressure (nCPAP) for noninvasive respiratory support in the NICU.

METHODS

Randomized, controlled, unblinded noncrossover trial in 432 infants ranging from 28 to 42 weeks' gestational age with planned nCPAP support, as either primary therapy or postextubation. The primary outcome was defined as a need for intubation within 72 hours of applied noninvasive therapy.

RESULTS

There was no difference in early failure for HHHFNC (23/212 [10.8%]) versus nCPAP (18/220 [8.2%]; P = .344), subsequent need for any intubation (32/212 [15.1%] vs 25/220 [11.4%]; P = .252), or in any of several adverse outcomes analyzed, including air leak. HHHFNC infants remained on the study mode significantly longer than nCPAP infants (median: 4 vs 2 days, respectively; P < .01), but there were no differences between study groups for days on supplemental oxygen (median: 10 vs 8 days), bronchopulmonary dysplasia (20% vs 16%), or discharge from the hospital on oxygen (19% vs 18%).

CONCLUSIONS

Among infants ≥28 weeks' gestational age, HHHFNC appears to have similar efficacy and safety to nCPAP when applied immediately postextubation or early as initial noninvasive support for respiratory dysfunction.

Treatment of obstructive sleep apnea reduces the risk of atrial fibrillation recurrence after catheter ablation

OBJECTIVES

The aim of this study was to examine the effect of continuous positive airway pressure (CPAP) therapy on atrial fibrillation (AF) recurrence in patients with obstructive sleep apnea (OSA) undergoing pulmonary vein isolation (PVI).

BACKGROUND

OSA is a predictor of AF recurrence following PVI. However, the impact of CPAP therapy on PVI outcome in patients with OSA is poorly known.

METHODS

Among 426 patients who underwent PVI between 2007 and 2010, 62 patients had a polysomnography-confirmed diagnosis of OSA. While 32 patients were "CPAP users" the remaining 30 patients were "CPAP nonusers." The recurrence of any atrial tachyarrhythmia, use of antiarrhythmic drugs, and need for repeat ablations were compared between the groups during a follow-up period of 12 months. Additionally, the outcome of patients with OSA was compared to a group of patients from the same PVI cohort without OSA.

RESULTS

CPAP therapy resulted in higher AF-free survival rate (71.9% vs. 36.7%; p = 0.01) and AF-free survival off antiarrhythmic drugs or repeat ablation following PVI (65.6% vs. 33.3%; p = 0.02). AF recurrence rate of CPAP-treated patients was similar to a group of patients without OSA (HR: 0.7, p = 0.46). AF recurrence following PVI in CPAP nonuser patients was significantly higher (HR: 2.4, p < 0.02) and similar to that of OSA patients managed medically without ablation (HR: 2.1, p = 0.68).

CONCLUSIONS

CPAP is an important therapy in OSA patients undergoing PVI that improves arrhythmia free survival. PVI offers limited value to OSA patients not treated with CPAP.

Mandibular advancement splint as short-term alternative treatment in patients with obstructive sleep apnea already effectively treated with continuous positive airway pressure

STUDY OBJECTIVES

CPAP is used as the first-line treatment for patients with severe OSA, but this machine is not always feasible to use on the long term. We performed a clinical trial to determine whether patients with OSA could use a mandibular advancement splint (MAS) as a short-term treatment alternative to CPAP.

METHODS

Twenty-two patients adherent with CPAP therapy were recruited to the study. Each patient used the MAS for approximately 4 months. The transition between CPAP to MAS was gradual, and patients were asked to start using MAS together with CPAP during the MAS titration until subjective improvement or maximum mandibular advancement was achieved. Sleepiness (ESS), quality of life (SAQLI), and polysomnography were recorded prior to and after MAS titration. Patients recorded CPAP or MAS usage for the following 3 months.

RESULTS

Seven women and 12 men with a mean age of 53.8 (± 12.1) years and mean body mass index of 28.1 (± 4.8) kg/m² completed the clinical trial. Prior to MAS, CPAP adherence was 5.8 h/night. AHI decreased significantly with MAS use compared to baseline (30.7 ± 23.1 vs 13.2 ± 11; p < 0.01). Fourteen patients (74%) had > 50% decrease in their AHI, while 2 patients had an increase in their AHI. There were no significant differences in SAQLI between MAS and CPAP treatment, while ESS decreased significantly on MAS. MAS self-reported usage was correlated with treatment efficacy (r = 0.52; p < 0.05). Seventy-five percent of the patients reported being sufficiently satisfied with MAS to continue to use it as an alternative short-term therapy.

CONCLUSIONS

MAS partially or completely reduced sleep disordered breathing in the majority of selected, successfully CPAP-treated severe OSA patients. Many patients can probably effectively use MAS as a short-term treatment alternative to CPAP.

Effect of adding postoperative noninvasive ventilation to usual care to prevent pulmonary complications in patients undergoing coronary artery bypass grafting: a randomized controlled trial

OBJECTIVE

We compared the efficacy of noninvasive ventilation with bilevel positive airway pressure added to usual care versus usual care alone in patients undergoing coronary artery bypass grafting.

METHODS

We performed a 2-group, parallel, randomized controlled trial. The primary outcome was time until fit for discharge. Secondary outcomes were partial pressure of carbon dioxide, forced expiratory volume in 1 second, atelectasis, adverse events, duration of intensive care stay, and actual postoperative stay.

RESULTS

A total of 129 patients were randomly allocated to bilevel positive airway pressure (66) or usual care (63). Three patients allocated to bilevel positive airway pressure withdrew. The median duration of bilevel positive airway pressure was 16 hours (interquartile range, 11-19). The median duration of hospital stay until fit for discharge was 5 days for the bilevel positive airway pressure group (interquartile range, 4-6) and 6 days for the usual care group (interquartile range, 5-7; hazard ratio, 1.68; 95% confidence interval, 1.08-2.31; P = .019). There was no significant difference in duration of intensive care, actual postoperative stay, and mean percentage of predicted forced expiratory volume in 1 second on day 3. Mean partial pressure of carbon dioxide was significantly reduced 1 hour after bilevel positive airway pressure application, but there was no overall difference between the groups up to 24 hours. Basal atelectasis occurred in 15 patients (24%) in the usual care group and 2 patients (3%) in the bilevel positive airway pressure group. Overall, 30% of patients in the bilevel positive airway pressure group experienced an adverse event compared with 59% in the usual care group.

CONCLUSIONS

Among patients undergoing elective coronary artery bypass grafting, the use of bilevel positive airway pressure at extubation reduced the recovery time. Supported by trained staff, more than 75% of all patients allocated to bilevel positive airway pressure tolerated it for more than 10 hours.

Obstructive sleep apnea and oxygen therapy: a systematic review of the literature and meta-analysis

BACKGROUND

Hypoxemia is an immediate consequence of obstructive sleep apnea. Oxygen (O2) administration has been used as an alternative treatment in patients with obstructive sleep apnea (OSA) who do not adhere to continuous positive airway pressure (CPAP) in order to reduce the deleterious effects of intermittent hypoxemia during sleep. This systematic review aims to investigate the effects of O2 therapy on patients with OSA.

METHOD

We conducted a systematic search of the databases Medline, Embase, Cochrane Central Register of Controlled Trials (1(st) Quarter 2011), Cochrane Database of Systematic Reviews (from 1950 to February 2011). Our search strategy yielded 4,793 citations. Irrelevant papers were excluded by title and abstract review, leaving 105 manuscripts. We reviewed all prospective studies that included: (1) a target population with obstructive sleep apnea, (2) O2 therapy and/or CPAP as a study intervention, (3) the effects of O2 on the apnea-hypopnea index (AHI), nocturnal hypoxemia, or apnea duration.

RESULTS

We identified 14 studies including a total of 359 patients. Nine studies were of single cohort design, while 5 studies were randomized control trials with 3 groups (CPAP, oxygen, and placebo/sham CPAP). When CPAP was compared to O2 therapy, all but one showed a significant improvement in AHI. Ten studies demonstrated that O2 therapy improved oxygen saturation vs. placebo. However, the average duration of apnea and hypopnea episodes were longer in patients receiving O2 therapy than those receiving placebo.

CONCLUSION

This review shows that O2 therapy significantly improves oxygen saturation in patients with OSA. However, it may also increase the duration of apnea-hypopnea events.

CPAP adherence of patients with obstructive sleep apnea

BACKGROUND

Continuous positive airway pressure (CPAP) and bi-level positive airway pressure (BPAP) are the gold standard treatments for obstructive sleep apnea syndrome (OSAS), but CPAP/BPAP is not well tolerated and requires long-term follow-up.

OBJECTIVE

We prospectively assessed subjective and objective adherence and factors that affect adherence in OSAS patients.

METHODS

Subjects using CPAP/BPAP were questioned about adverse effects of CPAP/BPAP and were assessed with the Epworth Sleepiness Scale (ESS) at the first, third, sixth, and twelfth month, and once every 6 months after the first year. CPAP/BPAP use and objective and subjective adherence were assessed. Subjects who used CPAP/BPAP for at least 4 hours per night for at least 70% of the days monitored were regarded as adherent, and those who did not were considered non-adherent. The relationships between adherence and demographic data, polysomnography findings, ESS scores, and adverse effects were statistically analyzed.

RESULTS

Six-hundred forty-eight subjects who were diagnosed with OSAS by polysomnography and accepted to use CPAP/BPAP in our sleep center between January 2005 and June 2011 were included. Four-hundred fifty-one subjects (69.6%) were men, and 197 (30.4%) were women. Two-hundred forty-eight (38.3%) subjects attended follow-ups, 246 (37.9%) were called by telephone, and 154 (23.8%) could not be reached. Of the whole population, 63.9% had obtained their CPAP/BPAP machine. In the 248 subjects who attended follow-ups, subjective adherence was 85.1% and objective adherence was 64.5%. Improvement in ESS score (P < .001) and satisfactory sleep (P < .001) were found to be significantly higher in the adherent group. Chest discomfort, difficulty falling asleep, and sleep disturbances were significantly higher in the non-adherent group (all P < .01).

CONCLUSIONS

Of the whole population, just 38.3% attended follow-ups. The objective adherence was lower than the subjective adherence in subjects who attended follow-ups. Younger subjects were more adherent, and the most important factors that correlated with adherence were substantial improvement of daytime sleepiness and effect of CPAP/BPAP on satisfactory sleep.

CONCLUSIONS

CPAP/BPAP adherence should be followed with objective monitoring.

Factors affecting CPAP acceptance in elderly patients with obstructive sleep apnea in Taiwan

BACKGROUND

The prevalence of obstructive sleep apnea (OSA) increases with age. Treatment often includes CPAP. CPAP adherence is correlated with disease severity and symptoms. We hypothesized that CPAP acceptance rates in elderly patients with OSA would be lower than in younger patients with OSA, and examined factors associated with CPAP acceptance.

METHODS

We reviewed the charts of 315 subjects with OSA (apnea-hypopnea index ≥ 5 events/h) who were treated at our hospital from 2008 to 2011 with CPAP therapy. All underwent CPAP titration testing before CPAP prescription. Subjects were grouped by age: young (25-40 y, n = 35), middle-age (41-65 y, n = 169), and elderly (> 65 y, n = 111). Demographic variables, excessive daytime sleepiness, overnight polysomnography study variables, CPAP acceptance, and CPAP adherence were compared. Regression analysis was performed to identify factors associated with acceptance.

RESULTS

The elderly subjects had less excessive daytime sleepiness and less pronounced alterations in overnight polysomnography variables than the subjects in the other groups, but had more cardiovascular comorbidities. The CPAP acceptance rate (overall 125/315, 39.7%) was significantly lower in the elderly group, compared with the younger group (31.5% vs 60%, P = .01). CPAP acceptance was associated with fewer comorbidities, higher excessive daytime sleepiness, and higher apnea-hypopnea index, but not age. CPAP adherence was not associated with age.

CONCLUSIONS

CPAP acceptance is low in elderly patients in Taiwan. CPAP acceptance, instead of CPAP adherence, is the critical issue with elderly patients with OSA.

Humidification performance of humidifying devices for tracheostomized patients with spontaneous breathing: a bench study

BACKGROUND

Heat and moisture exchangers (HMEs) are commonly used for humidifying respiratory gases administered to mechanically ventilated patients. While they are also applied to tracheostomized patients with spontaneous breathing, their performance in this role has not yet been clarified. We carried out a bench study to investigate the effects of spontaneous breathing parameters and oxygen flow on the humidification performance of 11 HMEs.

METHODS

We evaluated the humidification provided by 11 HMEs for tracheostomized patients, and also by a system delivering high-flow CPAP, and an oxygen mask with nebulizer heater. Spontaneous breathing was simulated with a mechanical ventilator, lung model, and servo-controlled heated humidifier at tidal volumes of 300, 500, and 700 mL, and breathing frequencies of 10 and 20 breaths/min. Expired gas was warmed to 37°C. The high-flow CPAP system was set to deliver 15, 30, and 45 L/min. With the 8 HMEs that were equipped with ports to deliver oxygen, and with the high-flow CPAP system, measurements were taken when delivering 0 and 3 L/min of dry oxygen. After stabilization we measured the absolute humidity (AH) of inspired gas with a hygrometer.

RESULTS

AH differed among HMEs applied to tracheostomized patients with spontaneous breathing. For all the HMEs, as tidal volume increased, AH decreased. At 20 breaths/min, AH was higher than at 10 breaths/min. For all the HMEs, when oxygen was delivered, AH decreased to below 30 mg/L. With an oxygen mask and high-flow CPAP, at all settings, AH exceeded 30 mg/L.

CONCLUSIONS

None of the HMEs provided adequate humidification when supplemental oxygen was added. In the ICU, caution is required when applying HME to tracheostomized patients with spontaneous breathing, especially when supplemental oxygen is required.

CPAP effect on recurrent episodes in patients with sleep apnea and myocardial infarction

BACKGROUND

Obstructive sleep apnea (OSA) is linked to increased cardiovascular risk, but the association between OSA and myocardial infarction (MI) remains controversial. Our objectives were to compare the frequency of OSA in patients with acute MI and in a population-based sample of control subjects, and to evaluate the impact of CPAP on recurrent MI and coronary revascularization.

METHODS

Case-control study with a 6-year follow-up of the case cohort. 192 acute MI patients and 96 matched control subjects without coronary artery disease (CAD) (ratio 2:1). After overnight polysomnography, CPAP was recommended if apnea-hypopnea index (AHI) ≥ 5, and a mean daily use >3.5h/day was considered necessary to maintain the treatment. Lipids, fasting glucose, blood pressure, spirometry, comorbidity and current treatment were also registered. End-points were recurrent MI or need of revascularization.

RESULTS

OSA was an independent predictor of MI, with odds ratio 4.9 (95% confidence interval [CI] 2.9-8.3, p=0.017). 63 MI patients without OSA, 52 untreated patients with OSA and 71 OSA patients treated with CPAP were included in the follow-up study. After adjustment for confounding factors, treated OSA patients had a lower risk of recurrent MI (adjusted hazard ratio 0.16 [95%CI 0.03-0.76, p=0.021]) and revascularization (adjusted hazard ratio 0.15 [95%CI 0.03-0.79, p=0.025]) than untreated OSA patients, and similar to non-OSA patients.

CONCLUSION

Mild-severe OSA is an independent risk factor for MI. Risk of recurrent MI and revascularization was lower in OSA patients who tolerated CPAP.

The comparison of CPAP and oral appliances in treatment of patients with OSA: a systematic review and meta-analysis

BACKGROUND

A systematic review and meta-analysis was performed to compare the outcomes of oral appliances (OAs) with those of CPAP in treatment of patients with obstructive sleep apnea (OSA).

METHODS

Relevant studies were retrieved from the following electronic databases, up to and including September 2012: MEDLINE, PubMed, EMBASE, and Central Register of Controlled Trials. The main outcomes were Epworth Sleepiness Scale score, health-related quality of life, cognitive performance, blood pressure, apnea-hypopnea index (AHI), arousal index, minimum SpO2, percent rapid eye movement sleep, treatment usage, side effects, treatment preference, and withdrawals.

RESULTS

Fourteen trials were finally included in this review. Our results demonstrated that the effects on Epworth Sleepiness Scale score (P = .31 and .09 in crossover and parallel-group trials), health-related quality of life, cognitive performance, and blood pressure of OAs and CPAP were similar. Besides, pooled estimates of crossover trials suggested a significant difference in favor of CPAP regarding AHI (P < .001), arousal index (P = .001), and minimum SpO2 (P < .001), while pooled estimates of parallel-group trials showed a significant difference in favor of CPAP regarding AHI (P < .001) and percent rapid eye movement sleep (P = .02). Moreover, OAs and CPAP yielded fairly similar results in terms of treatment usage (P = .26 for hours/night in crossover trials, and P = .14 for hours/night and P = .19 for nights/week in parallel-group trials), treatment preference, side effects, and withdrawals (P = .34 in parallel-group trials).

CONCLUSIONS

CPAP yielded better polysomnography outcomes, especially in reducing AHI, than OAs, indicating that OAs were less effective than CPAP in improving sleep-disordered breathing. However, similar results from OAs and CPAP in terms of clinical and other related outcomes were found, suggesting that it would appear proper to offer OAs to patients who are unable or unwilling to persist with CPAP.

CPAP adherence in patients with newly diagnosed obstructive sleep apnea prior to elective surgery

BACKGROUND

Obstructive sleep apnea (OSA) is prevalent in the surgical population, and it has been suggested that preoperative patients should be screened and treated for OSA. However, it remains unclear whether patients diagnosed with OSA in the preoperative period adhere to prescribed CPAP therapy.

OBJECTIVE

Our aim was to objectively quantify CPAP adherence, investigate predictors of poor CPAP adherence, and to establish an optimal CPAP setting in a cohort of presurgical patients diagnosed with OSA as part of the preoperative work-up.

METHODS

In a retrospective observational study, we collected data on all adult presurgical patients seen by the Anesthesia Perioperative Medicine Clinic (APMC) who screened positive for OSA on the STOP-Bang questionnaire and underwent an in-laboratory diagnostic polysomnogram (PSG) before surgery. CPAP was offered to patients with moderate or severe OSA. Objective CPAP adherence was recorded during the perioperative period. Factors associated with reduced CPAP adherence were delineated. Patient characteristics were compared between those with STOP-Bang scores of 3-4 and those with higher scores (STOP-Bang score ≥ 5).

RESULTS

During a 2-year period, 431 patients were referred and 211 patients completed a PSG. CPAP therapy was required in 65% of patients, and the optimal level was 9 ± 2 cm H(2)O. Objective CPAP adherence was available in 75% of patients who received CPAP therapy; median adherence was 2.5 h per night, without any significant difference between the STOP-Bang subgroups. African American race, male gender, and depressive symptomatology were independent predictors of reduced CPAP adherence. Severe OSA was significantly more prevalent in patients with a STOP-Bang score ≥ 5 than those whose score was 3-4 (55.1% versus 34.4%, p = 0.005). However, optimum CPAP pressure levels and adherence to therapy did not differ between the 2 STOP-Bang groups.

CONCLUSIONS

Adherence to prescribed CPAP therapy during the perioperative period was extremely low. African American race, male gender, and depressive symptoms were independently associated with reduced CPAP usage. Further research is needed to identify and overcome barriers to CPAP acceptance and adherence in the perioperative setting.

An implementation protocol for noninvasive ventilation prescription: the physiotherapist's role in an Italian hospital

BACKGROUND

For patients with chronic respiratory failure or sleep breathing disorders, adaptation and training are important prerequisites for successful home noninvasive ventilation (NIV) and CPAP. In Europe, management of NIV/CPAP is sometimes performed by physiotherapists (PTs). However, their role within the NIV/CPAP management team is not well defined.

OBJECTIVE

To describe the implementation of a standardized protocol to NIV adaptation for patients with chronic respiratory disease. Secondary outcomes were to evaluate the PT's role and time-consumption.

METHODS

We enrolled 201 patients with chronic respiratory disease, referred to the cardiopulmonary rehabilitation service (CPRS). Anthropometric and clinical data, adaptation sessions, ventilator typology, side effects, plus activities conducted by the CPRS were recorded. The time spent on a single protocol task plus total time spent on the entire management procedure for NIV/CPAP adaptation was also documented.

RESULTS

Adaptation to NIV/CPAP was completed in 8.2 ± 3.2 sessions, lasting 17.2 ± 15.4 min/session. Total CPRS activity included 61% adaptation procedures, 22% educational sessions, 8% evaluation, 7% monitoring and follow-up, and 2% administrative activities. CPRS time-consumption per patient was 149.5 ± 113.7 min. Total CPRS time-consumption was 28,870 min, corresponding to 1.52 hours/working day and 21% of total PT daily activity. After protocol implementation, PTs were able to cover 65% and 35% of the time devoted to ventilation procedures typically carried out by physicians and nurses, respectively. Amyotrophic lateral sclerosis/neuromuscular patients required more time for adaptation and education, compared to patients with obstructive sleep apnea syndrome (P < .001) and pulmonary restrictive disease (P < .001).

CONCLUSIONS

Our study has demonstrated that the PTs can play a key role in the respiratory care management of patients with chronic respiratory disease and sleep breathing disorders with neuromuscular diseases requiring higher time consumption, and the inclusion of PTs in the NIV/CPAP management procedure reduces the time spent by other health professionals. The cost effectiveness of this management needs to be verified in larger clinical trial settings.

Effective sleep apnoea treatment improves cardiac function in patients with chronic heart failure

BACKGROUND

Sleep disordered breathing (SDB) is highly prevalent in patients with chronic heart failure (CHF) and is associated with adverse effects on cardiac geometry and function. Continuous positive airway pressure (CPAP) has been proved an effective treatment modality for obstructive sleep apnoea (OSA), whereas adaptive servoventilation (ASV) is more effective in patients with central sleep apnoea (CSA). The impact of selection of therapy and effective apnoea alleviation on cardiac performance and reverse left ventricular remodelling (r-LVR) has not yet been evaluated.

METHODS

Eighty five patients with stable CHF were screened for SDB and underwent polysomnography and treatment according to the type of SDB. Clinical evaluation and a comprehensive echocardiographic study was performed before initiation of therapy and after six months of effective treatment (ventilator use >5h/day with AHI <5 events/h).

RESULTS

Seventeen compliant patients under effective treatment were included in the analysis (8 OSA under Autoset CPAP and 9 CSA under ASV). In both groups, a significant improvement in all measured, conventional and TDI LV systolic indexes was recorded, including LVEF (32% ± 6% vs. 27% ± 6%, p<0.001). A decrease in LV end-systolic volume (189 ± 94 ml vs. 211 ± 88 ml, p=0.015, difference >10%) was indicative of r-LVR. Furthermore, RV systolic parameters were also increased (TAPSE, p<0.001; systolic TDI wave from lateral tricuspid annular aspect, p=0.001), whereas right heart dimensions and areas were diminished, indicating better pulmonary haemodynamics. Moreover, a significant improvement in patients' clinical status, as evaluated by New York Heart Association Class was also documented at the end of six months follow-up.

CONCLUSIONS

Effective alleviation of SDB in CHF patients is associated with significant improvements in LV and RV systolic function and r-LVR. Longitudinal studies are needed to evaluate effects on morbidity and mortality.

Obstructive sleep apnea and type 2 diabetes: is there a link?

Type 2 diabetes is a chronic illness that is increasing in epidemic proportions worldwide. Major factors contributing to the development of type 2 diabetes include obesity and poor lifestyle habits (e.g., excess dietary intake and limited physical activity). Despite the proven efficacy of lifestyle interventions and the use of multiple pharmacological agents, the economic and public health burden of type 2 diabetes remains substantial. Obstructive sleep apnea (OSA) is a treatable sleep disorder that is pervasive among overweight and obese adults, who represent about two thirds of the U.S. population today. An ever-growing number of studies have shown that OSA is associated with insulin resistance, glucose intolerance and type 2 diabetes, independent of obesity. Evidence from animal and human models that mimic OSA provides potential mechanisms for how OSA may alter glucose metabolism. Up to 83% of patients with type 2 diabetes suffer from unrecognized OSA and increasing severity of OSA is associated with worsening glucose control. However, it is still unclear whether OSA may lead to the development of diabetes over time. More data from large-scale longitudinal studies with rigorous assessments of diabetes and OSA are needed. In addition, there is still controversy whether continuous positive airway pressure (CPAP) treatment of OSA improves glucose metabolism. Large-scale randomized-controlled trials of CPAP treatment of OSA with well-validated assessments of insulin sensitivity and glucose tolerance are needed. These studies may reveal that OSA represents a novel, modifiable risk factor for the development of prediabetes and type 2 diabetes.

Predictors of positive airway pressure therapy adherence in children: a prospective study

STUDY OBJECTIVES

Children with obstructive sleep apnea are increasingly being treated with positive airway pressure (PAP), particularly if they have underlying medical conditions. Although PAP is an effective treatment, its use is challenging due to poor adherence. We hypothesized that demographic, psychosocial, and polysomnographic parameters would be related to PAP adherence. We therefore prospectively collected data potentially pertaining to PAP adherence, and correlated it with PAP use.

METHODS

Fifty-six patients and their parents completed a series of psychosocial questionnaires prior to PAP initiation. Objective adherence data were obtained after 1 and 3 months of PAP use.

RESULTS

The population was primarily obese; 23% had neurodevelopmental disabilities. PAP adherence varied widely, with PAP being worn 22 ± 8 nights in month-1, but mean use was only 3 ± 3 h/night. The greatest predictor of use was maternal education (p = 0.002 for nights used; p = 0.033 for mean h used/night). Adherence was lower in African American children vs other races (p = 0.021). In the typically developing subgroup, adherence correlated inversely with age. Adherence did not correlate with severity of apnea, pressure levels, or psychosocial parameters other than a correlation between family social support and nights of PAP use in month-3.

CONCLUSIONS

PAP adherence in children and adolescents is related primarily to family and demographic factors rather than severity of apnea or measures of psychosocial functioning. Further research is needed to determine the relative contributions of maternal education, socioeconomic status and cultural beliefs to PAP adherence in children, in order to develop better adherence programs.

Long-term use of a nasal expiratory positive airway pressure (EPAP) device as a treatment for obstructive sleep apnea (OSA)

STUDY OBJECTIVES

Evaluate the long-term durability of treatment response and safety of a nasal expiratory positive airway pressure (EPAP) device used to treat obstructive sleep apnea (OSA).

DESIGN

A prospective, multicenter, single-arm, open-label extension to a 3-month EPAP vs sham randomized clinical trial

SETTING

13 sites including both academic and private sleep disorder centers

PATIENTS

OSA patients in the EPAP arm of the EPAP vs sham randomized study who used the EPAP device ≥ 4 h per night, ≥ 5 nights per week on average during months 1 and 2 of the 3-month trial and had ≥ 50% reduction in AHI or AHI reduction to < 10 documented by polysomnography, comparing the 3-month device-on PSG to the week-one device-off PSG.

INTERVENTIONS

Treatment with a nasal EPAP device (N = 41) for 12 months. Polysomnography (PSG) on the patients wearing the device was performed after 12 months of treatment. The month 12 device-on PSG data from the analyzable subject cohort (N = 34) was compared to the week 1 device-off PSG from the EPAP vs sham trial.

MEASUREMENTS AND RESULTS

Of the 51 patients eligible, 34 were still using the EPAP device at the end of 12 months. Median AHI was reduced from 15.7 to 4.7 events/h (week 1 device-off versus month 12 device-on). The decrease in the AHI (median) was 71.3% (p < 0.001). The median proportion of sleep time with snoring was reduced by 74.4% (p < 0.001). Over 12 months of EPAP treatment, the Epworth Sleepiness Scale decreased (11.1 ± 4.2 to 6.0 ± 3.2, p < 0.001), and the median percentage of reported nights used (entire night) was 89.3%.

CONCLUSIONS

Nasal EPAP significantly reduced the AHI, improved subjective daytime sleepiness and reduced snoring after 12 months of treatment. Long-term adherence to EPAP was excellent in those who had a positive clinical response at month 3 of the EPAP vs sham study.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov TRIAL NAME: Extension Study of Original Protocol AERO C009 for Obstructive Sleep Apnea-hypopnea (AERO C009E). URL: http://clinicaltrials.gov/ct2/show/NCT00849043?term=Ventus+Medical&rank=2.

REGISTRATION NUMBER

NCT00849043.

Respiratory event detection by a positive airway pressure device

STUDY OBJECTIVES

Compare automatic event detection (AED) of respiratory events using a positive airway pressure (PAP) device with manual scoring of polysomnography (PSG) during PAP treatment of obstructive sleep apnea (OSA).

DESIGN

Prospective PSGs of patients using a PAP device.

SETTING

Six academic and private sleep disorders centers.

PATIENTS

A total of 148 PSGs from 115 participants with OSA (apnea-hypopnea index [AHI] ≥ 15 events/hr) were analyzed.

INTERVENTIONS

A signal generated by the PAP device identifying the AED of respiratory events based on airflow was recorded during PSG.

MEASUREMENTS AND RESULTS

The PSGs were manually scored without visualization of the AED signal and scoring of a hypopnea required a ≥ 4% oxygen desaturation. The apnea index (AI), hypopnea index (HI), and AHI by manual score and PAP AED were compared. A customized computer program compared individual events by manual scoring and AED to determine the true positive, false positive, false negative, or true negative events and found a sensitivity of 0.58 and a specificity of 0.98. The AHI, AI, and HI by the two methods were highly correlated. Bland-Altman analysis showed better agreement for AI than HI. Using a manually scored AHI of ≥ 10 events/hr to denote inadequate treatment, an AED AHI ≥ 10 events/hr had a sensitivity of 0.58 and a specificity of 0.94.

CONCLUSIONS

An AHI < 10 events/hr by PAP AED is usually associated with good treatment efficacy. Differences between manually scored and AED events were primarily due to different criteria for hypopnea detection.

Randomized, double-blind clinical trial of two different modes of positive airway pressure therapy on adherence and efficacy in children

STUDY OBJECTIVES

To determine the effects of bilevel positive airway pressure with pressure release technology (Bi-Flex) on adherence and efficacy in children and adolescents compared to standard continuous positive airway pressure (CPAP) therapy. We hypothesized that Bi-Flex would result in improved adherence but similar efficacy to CPAP.

METHODS

This was a randomized, double-blinded clinical trial. Patients with obstructive sleep apnea were randomized to CPAP or Bi-Flex. Repeat polysomnography was performed on pressure at 3 months. Objective adherence data were obtained at 1 and 3 months.

RESULTS

56 children and adolescents were evaluated. There were no significant differences in the number of nights the device was turned on, or the mean number of minutes used at pressure per night for CPAP vs Bi-Flex (24 ± 6 vs 22 ± 9 nights, and 201 ± 135 vs 185 ± 165 min, respectively, for Month 1). The apnea hypopnea index decreased significantly from 22 ± 21/h to 2 ± 3/h on CPAP (p = 0.005), and 18 ± 15/h to 2 ± 2/h on Bi-Flex (p < 0.0005), but there was no significant difference between groups (p = 0.82 for CPAP vs Bi-Flex). The Epworth Sleepiness Scale decreased from 8 ± 5 to 6 ± 3 on CPAP (p = 0.14), and 10 ± 6 to 5 ± 5 on Bi-Flex (p < 0.0005; p = 0.12 for CPAP vs Bi-Flex).

CONCLUSIONS

Both CPAP and Bi-Flex are efficacious in treating children and adolescents with OSAS. However, adherence is suboptimal with both methods. Further research is required to determine ways to improve adherence in the pediatric population.