Taro Soga

Nagoya University, Nagoya-shi, Aichi-ken, Japan

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Publications (5)6.32 Total impact

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    ABSTRACT: Sleep disturbances manifesting as insomnia, daytime sleepiness, fatigue, and other symptoms are frequently found in patients with end-stage renal disease that is being treated with dialysis. Many factors, including neurosis, uremic symptoms, dialysis drugs, and sleep-wake rhythms have been suggested as potential causes for these sleep disturbances. We examined sleep apnea/hypopnea and heart rate variability (HRV) reflecting autonomic activity in hemodialysis patients on their hemodialysis and non-hemodialysis days using a home medical care device (Morpheus C, TEIJIN). Eleven hemodialysis patients and 14 healthy adults were enrolled in this study. We calculated the number of apnea/hypopnea episodes per hour (apnea/hypopnea index: AHI) and HRV (percentage of R-R intervals that differ by at least 50 ms from the previous interval: pNN50, very low frequency: VLF, low frequency: LF, high frequency: HF and LF/ HF). There was no significant difference in the AHI between hemodialysis and non-hemodialysis days. The heart rate in hemodialysis patients on non-hemodialysis days was significantly higher than in the controls, whereas the pNN50 was significantly lower in hemodialysis patients on non-hemodialysis days than in the controls. Although VLF was significantly lower in hemodialysis patients on non-hemodialysis days compared to the controls, there were no significant differences in LF, HF or LF/HF between the two groups. Hemodialysis itself might not be an important contributing factor in sleep-related breathing disturbances. The simultaneous analysis of HRV reflecting autonomic activity and sleep-disordered breathing on both hemodialysis and non-hemodialysis days provides important information.
    Nagoya journal of medical science 09/2008; 70(3-4):83-8.
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    ABSTRACT: The aim of this study was to clarify the interaction of lateral and supine sleeping positions with upper airway morphology in patients with obstructive sleep apnea syndrome (OSAS). Thirty-one patients with OSAS, whose apnea/hypopnea index (AHI: number of episodes of apnea or hypopnea per hour) was over 15, were enrolled in this study. Subjects were divided in two groups according to positional effects on their AHI. In six patients, a lateral posture decreased the AHI by 50% and more (responders); in the remaining 25, lateral positioning decreased the AHI by less than 50% or even increased the AHI (nonresponders). AHI and body mass index (BMI) of the responders tended to be lower and their mean age was younger than those of nonresponders, but these differences were not statistically significant. We compared the upper airway morphology between the responders and the nonresponders regarding the tonsil size, tongue position (modified Mallanpati grade, reflecting the space between the tongue and soft palate) and the width of the fauces and retroglossal space. In addition, we compared nasal resistance between the groups using active rhinomanometry. The width of the fauces was significantly greater (P=0.041) among the responders than among the nonresponders. However, the other parameters were not consistently different between the two, and these differences were not statistically significant either. The distance between the fauces was the sole morphological feature to distinguish the responders and the nonresponders to the positional therapy in patients with OSAS. Lateral positioning during sleep might be a recommended sleep hygiene for OSAS patients with wide fauces.
    Auris, nasus, larynx 08/2008; 36(3):305-9. · 0.58 Impact Factor
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    ABSTRACT: Continuous positive airway pressure (CPAP) is considered as the standard therapy for obstructive sleep apnea syndrome (OSAS), but some patients with OSAS are unable to accept CPAP due to nasal obstruction and poor nasal airflow. We assessed the influence of nasal resistance before beginning CPAP treatment on the initial acceptance of CPAP in OSAS patients. The study subjects comprised 77 patients (74 males, 3 females) with primary OSAS, all of whom received CPAP treatment with nasal masks. Before trials, all subjects underwent overnight polysomnography, and nasal resistance was measured with active anterior rhinomanometry in the seated position on the first day of CPAP trial. The CPAP treatment was accepted by 56 patients after the initial trials with overnight polysomnography. Body mass index, the number of apnea/hypopnea episodes per hour (apnea/hypopnea index; AHI), and the number of episodes per hour with an oxygen desaturation of >3% (oxygen desaturation index) were significantly higher (p<0.01) and nasal resistance was lower (p=0.003) in patients who accepted CPAP than in those who did not. Logistic regression analysis, with patient age, body mass index, Epworth sleepiness scale score, AHI, oxygen desaturation index, and nasal resistance before CPAP treatment as explanatory variables, showed that nasal resistance (OR+0.1 Pa/cm3/s: 1.48; p=0.002) and AHI (OR+1 event/h: 0.93; p=0.003) were significant factors for CPAP non-acceptance. Nasal resistance before the beginning of CPAP treatment has a significant effect on the acceptance of CPAP in OSAS patients, and hence, could be a predictive parameter for the initial acceptance of CPAP.
    Respiration 01/2007; 74(1):56-60. · 2.92 Impact Factor
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    ABSTRACT: Sleep disturbance and the use of hypnotic medications are common in patients on hemodialysis. Factors that contribute to sleep disturbance and the use of hypnotic medications in hemodialysis patients were investigated. With the use of a questionnaire-based survey, we examined the prevalence of symptoms that reflect sleep disorders such as insomnia, restless legs syndrome (RLS), and snoring and use of hypnotic medications in 252 hemodialysis patients. The overall prevalence of insomnia was 59.1%, with the prevalence of difficulty in initiating sleep (DIS), difficulty in maintaining sleep (DMS), and early morning awakening (EMA) being 47.6, 24.2, and 28.2%, respectively. Daytime sleepiness and habitual snoring were reported by 42.5 and 33.7%, respectively. The prevalence of routine use of hypnotic drugs was 25.8%. Both RLS and age were significantly associated with insomnia [odds ratio (OR), 3.75; p 0.001, OR, 1.03; p < 0.01]. RLS was a significant factor for DIS, DMS, and EMA (OR, 2.26; p < 0.05, OR, 3.44; p < 0.0005, OR, 4.25; p < 0.0005) and age was a significant factor for DMS and EMA (OR, 1.03; p = 0.053, OR, 1.05; p < 0.005). Both insomnia and snoring were associated with the use of hypnotic drugs (OR, 2.97; p < 0.001, 1.59; p=0.13). Both RLS and sleep-disordered breathing may contribute to sleep disturbance in hemodialysis patients. RLS in particular may be an important factor in insomnia, which in turn is likely responsible for the high prevalence of hypnotic drug use in hemodialysis patients.
    Internal Medicine 02/2006; 45(22):1273-8. · 0.97 Impact Factor
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    ABSTRACT: Obstructive sleep apnea syndrome (OSAS) is related to diurnal sympathetic hyperactivity and increased blood pressure, both factors that are likely to lead to the development of cardiovascular disease. The study investigated whether 24-h urinary catecholamines would reflect the effect of obstructive sleep apnea on autonomic activity. Standard polysomnography was performed in 17 patients with OSAS (age 53.7 +/- 13.5 years, mean +/- standard deviation). The number of apnea/hypopnea episodes per hour of sleep (apnea/hypopnea index [AHI]); number of oxygen desaturation episodes per hour (desaturation index [DSI]); arousals per hour (arousal index); lowest oxygen saturation (lowest SpO2); and percentages of stages 1, 2, 3/4, and rapid eye movement sleep (% stage 1, -2, and -3/4, and % REM, respectively) were measured. Overnight continuous positive airway pressure (CPAP) titration was performed the night after the baseline sleep measurements had been taken. Twenty-four-hour urinary adrenaline and noradrenaline were also examined. During the CPAP treatment, both 24-h urinary adrenaline and noradrenaline were significantly lower compared with natural sleep. Continuous positive airway pressure significantly decreased the AHI, DSI, % stage 1, and arousal index and significantly increased the lowest SpO2. There were no significant differences in % stage 2, % stage 3/4, and % REM between before and during CPAP treatment. Multiple analysis of covariance tests revealed that lowest SpO2 was the most important factor for increasing 24-h urinary noradrenaline levels (F = 4.75, p = 0.048). One night CPAP treatment could improve autonomic dysfunction. The assessment of 24-h urinary noradrenaline would provide important information for evaluating the effect of CPAP treatment.
    Clinical Cardiology 12/2005; 28(11):519-22. · 1.83 Impact Factor