Hiroyuki Sawatari

Cumulative Hypoxemia During Sleep Predicts Vascular Endothelial Dysfunction in Patients With Sleep-Disordered Breathing

BACKGROUND Sleep-disordered breathing (SDB) is associated with repeated intermittent hypoxemia, and it is known as one of the risk factors for cardiovascular diseases. Previous studies assessing the effects of frequency and depth of hypoxemia on cardiovascular diseases have shown conflicting results. The aim of the current study was to clarify what SDB-related parameters most predict endothelial dysfunction to better understand the pathogenesis of endothelial dysfunction in patients with SDB. METHODS We conducted polysomnography (PSG) and measured flow-mediated vasodilation response (%FMD) in 50 outpatients suspected of SDB. Evaluated indices included: apnea-hypopnea index (AHI), 3% oxygen desaturation index (3%ODI), averaged arterial oxygen saturation (averaged SpO2), lowest arterial oxygen saturation (lowest SpO2), ratio of arterial oxygen saturation <90% (<SpO2 90%), and averaged time desaturation summation index (TDS: [100%-averaged SpO2] × total sleep time). RESULTS Significant differences were observed only in the TDS between the first and third (P = 0.03) and between the first and forth (P = 0.04) quartile groups, stratified by %FMD. The %FMD showed a significant relationship with TDS (β = -0.47, P = 0.001), even after adjusting for confounding factors (β = -0.33, P = 0.02). In contrast, AHI, 3%ODI, averaged SpO2, lowest SpO2, and <SpO2 90% showed no significant relationships. CONCLUSIONS This study shows the validity of TDS in predicting endothelial damage in patients with SDB. Cumulative hypoxemia, rather than the frequency of hypoxemic events presented as AHI, may be a greater contributing factor in causing endothelial dysfunction. A simple index like TDS may be a useful and novel indicator of the influence of SDB on the vasculature.

Influence of primary and secondary prevention indications on anxiety about the implantable cardioverter-defibrillator

Implantable cardioverter‐defibrillators (ICDs) have been established for primary and secondary prevention of fatal arrhythmias. However, little is known about the influence of ICD indications on quality of life (QOL) and psychological disturbances. This study aimed to examine whether there were differences in QOL and psychological distress in patients that have an ICD for primary or secondary prevention of fatal arrhythmias.

Obstructive sleep apnea-related symptoms in Japanese people with Down syndrome

This study evaluated the prevalence of obstructive sleep apnea-related symptoms and assessed the relationship with obesity or unusual sleep postures in Down syndrome patients in Japan. We obtained the demographic characteristics, sleep postures, and obstructive sleep apnea-related symptoms experienced by 90 people as reported by their caregivers. Although 71% reported snoring and 59% arousals, obstructive sleep apnea-related symptoms were not significantly different between obese and non-obese participants. The youngest age group had the fewest obstructive sleep apnea-related symptoms, especially symptoms of snoring. The odds for arousal, nocturia, and apnea tended to be higher in the unusual sleep-postures group. Unusual sleep postures were most frequent in the group 6-15 years of age. People with Down syndrome might sleep in unusual postures to avoid upper airway obstruction caused by other anatomical factors. For nurses and other health professionals working in mainstream service, it is important to screen all persons with Down syndrome for symptoms suggestive of obstructive sleep apnea, particularly those six years of age and older, and to refer them for further evaluation for sleep disorders.

Seasonal ambient changes influence inpatient falls

Background falls by inpatients often result in serious injuries and deterioration in a patients physical abilities and quality of life, especially among older individuals. Although various factors have been found to be associated with falls, the combined effects of behavioural and ambient factors are not fully evaluated. Objective we investigated the influence of both behavioural and ambient factors on inpatient falls, focusing on seasonal and diurnal variations. Design retrospective study. Methods we surveyed the incident reports related to falls from April 2010 to March 2014 and examined the relationship between the incidents and seasonal and diurnal variations in behavioural and ambient factors, including the sunrise time, the night-time length and temperature. Results we identified 464 fallers from 3,037 incident reports. The average fall-rate of the study population was 1.4 ± 0.5/1,000 occupied bed-days. The seasonal and diurnal variations in falls were compared. The number of falls around dawn in October-February was higher than that in April-September. Toileting was the behaviour most frequently related to the falls (56.9%, n = 264), and 57.1% of the falls occurred at night. A multivariate analysis showed that the night-time length was significantly related to an increase in night-time falls (P = 0.047). Conclusion these results suggested that the inpatient falls increased in the early morning from November to March and tended to be related to toileting activities. Considering these results, additional attention and support during the higher risk hours and seasons, especially in relation to toileting activities, might help to reduce the incidence of falls. Clinical trial name, URL and registration number N/A (Because of retrospective nature).

Different Physiological and Subjective Responses to the Hyperthermia Between Young and Older Adults: Basic Study for Thermal Therapy in Cardiovascular Diseases

BACKGROUND Thermal therapy has been used as adjuvant therapy in patients with cardiovascular disease. However, little is known about responses to thermal stress in older adults. We examined the effects of thermal stress in younger and older healthy Japanese individuals. METHODS The study included 12 young (mean age, 22 years) and 12 older (mean age, 68 years) healthy adults and was performed under strict temperature and humidity control to minimize confounding. Participants lay supine throughout three consecutive 30-minute phases: Phase I (heating at 70°C in a dome-shaped sauna), Phase II (insulation in the sauna), and Phase III (cool down). Physiological parameters and subjective thermal sensations were compared within and between two age groups. RESULTS Mean skin temperature increased significantly in both age groups (Phase I) and after the first 10 minutes was higher among older adults (by 6.8°C vs 6.0°C among younger; p < .01). Mean rectal temperature increased by 0.6°C in both groups (Phase II). Mean heart rate increased significantly in both age groups (Phase II) and was higher among younger adults (by 21.4 vs 11.3 beats/min among older adults; p < .05). Both systolic (by 15.1 mmHg) and diastolic (by 10.5 mmHg) blood pressure dropped significantly among older adults (Phase I), returning to baseline in Phase III; no changes were noted among those younger. There was no between-group difference in fluid loss or thermal sensations. CONCLUSIONS Compared with younger adults, older adults are more likely to drop blood pressure in response to thermal stress but had similar fluid loss and subjective responses.

Cardiac and respiratory effects of deep regional hyperthermia using an 8 MHz radiofrequency-capacitive device on patients with cancer

Abstract Purpose: Hyperthermia (HT), an adjuvant therapy for variable cancers, may cause physiological changes in the patients, which may lead to cardiovascular problems. Among various HT treatments, the physiological effects of deep regional HT are still unclear. We examined the physiological alterations throughout deep regional HT to improve the HT safety. Materials and methods: Thirty-one patients (age: 61 ± 12 years) with cancer received HT in the thoracic or upper abdominal regions using an 8-MHz radiofrequency-capacitive-device for 50 min. Rectal temperature (Trec), systolic and diastolic blood pressures (SBP and DBP), pulse rate (PR), respiratory rate (RR), percutaneous oxygen saturation (SpO2) and sweating volume were evaluated throughout HT. Results: At 50 min after starting HT, Trec, PR and RR were significantly increased compared with the baseline values (Trec: 38.2 ± 1.4 vs. 36.3 ± 0.8 °C, p < 0.001, PR: 104 ± 15 vs. 85 ± 16 bpm, p < 0.05, RR: 23 ± 3 vs. 21 ± 3/min, p < 0.05). Although the average SBP and DBP were both stable during HT in a recumbent position, these values dropped significantly in a standing position (SBP: 113 ± 16 vs. 127 ± 18 mmHg, p < 0.001, DBP: 70 ± 12 vs. 75 ± 13 mmHg, p < 0.01). The total amount of sweating was 356 ± 173 g/m2 on average. Conclusions: Deep regional HT increased the deep body temperature and resulted in an increase of sweating with peripheral vasodilatation. Consequently, a significant reduction in BP would be induced on standing after HT. Careful attention is needed for patients receiving HT, especially when standing after HT.

Left Ventricular Ejection Fraction Predicts Severity of Posttraumatic Stress Disorder in Patients With Implantable Cardioverter-Defibrillators.

Implantable cardioverter‐defibrillators (ICD) have provided effective therapy for fatal arrhythmia. However, ICD patients are known to develop psychological problems, such as posttraumatic stress disorder (PTSD), if they have experienced potentially fatal arrhythmia and ICD shocks. Little is known about the factors influencing PTSD in ICD patients.

A Nationwide Cross-sectional Study on Congenital Heart Diseases and Symptoms of Sleep-disordered Breathing among Japanese Down's Syndrome People

OBJECTIVE It is well known that people with Downs syndrome (DS) frequently complicate with congenital heart diseases (CHDs). Patients with heart diseases often have sleep-disordered breathing as a co-morbidity (SDB) which worsens the heart diseases. However, the relationship between SDB and CHDs in DS people has not yet been fully elucidated. The aim of this study was to establish the association between SDB and CHDs in DS people using data from a large nationwide questionnaire survey in Japan. METHODS We conducted a cross-sectional questionnaire survey of a randomly selected sample of 2,000 DS people and their caregivers throughout Japan to examine the associations between observed signs of SDB and CHDs in DS people. The questionnaire included the presence of SDB symptoms (snoring, apnea, arousal, nocturia, and napping) and CHDs (the presence and types of CHDs). RESULTS Of the 1,222 replies received from the caregivers, 650 reported complications of some type of CHDs. The observed apnea tended to be higher among DS people with CHDs than those without CHDs (OR=1.28, 95% CI=0.97-1.70, p=0.09). DS people with tetralogy of Fallot reported significantly more frequent apnea than those without CHDs (OR=3.10, 95% CI=1.36-7.05, p<0.01). CONCLUSION SDB prevailed among DS people with severe CHDs, such as tetralogy of Fallot. Careful attention to the signs of SDB in such patients may lead to earlier clinical intervention removing the vicious cycle between SDB and CHDs.

A nationwide, cross-sectional survey on unusual sleep postures and sleep-disordered breathing-related symptoms in people with Down syndrome

BACKGROUND People with Down syndrome (DS) often have sleep-disordered breathing (SDB). Unusual sleep postures, such as leaning forward and sitting, are observed in people with DS. This study aimed to clarify the prevalence of unusual sleep postures and their relationships with SDB-related symptoms (SDB-RSs), such as snoring, witnessed apnoea, nocturnal awakening and excessive daytime sleepiness. METHODS A questionnaire, including demographic characteristics and the presence of unusual sleep postures, as well as SDB-RSs, was completed by 1149 parents of people with DS from Japan. RESULTS Unusual sleep postures were recorded in 483 (42.0%) people with DS. These participants were significantly younger and had a history of low muscle tone more frequently than people without unusual sleep postures. In all ages, the leaning forward posture was more frequent than sitting. People with DS with unusual sleep postures suffered from SDB-RSs. Those who slept in the sitting posture had more frequent SDB-RSs than did those who slept with the leaning forward posture. Snoring, witnessed apnoea and nocturnal awakening were observed in 73.6, 27.2 and 58.2% of participants, respectively. Snoring increased with aging. Witnessed apnoea was more common in males and in those with hypothyroidism than in females and in those without hypothyroidism. CONCLUSIONS Our study shows that there is a close relationship between unusual sleep postures and SDB-RSs. We recommend that all people with DS with unusual sleep postures should be checked for the presence of SDB.

Effect of water bath temperature on physiological parameters and subjective sensation in older people

In Japan, the incidence of water bathing‐related cardiopulmonary accidents among older people is high in winter. The purpose of the present study was to investigate alterations in physiological characteristics and subjective thermal sensations of older people when bathing in a cool environment.