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Biomedical subjects

M Kryger

Publications and source records attributed to M Kryger.

At least 19 recordsLinked to original sources
PubMed2006

Gender differences on polysomnographic findings in Greek subjects with obstructive sleep apnea syndrome.

BACKGROUND AND PURPOSE: Studies from North American clinics have reported that females with obstructive sleep apnea syndrome (OSAS) are about the same age as males but are heavier, have less severe apnea and make up a much smaller proportion of cases. We examined polysomnographic differences between Greek men and women with OSAS in order to study the influence of gender on clinical presentation and laboratory findings. PATIENTS AND METHODS: This retrospective study included a cohort of 1,010 Greek patients (844 males, 166 females) diagnosed with OSAS by overnight polysomnography (PSG), who were referred to the Sleep Disorders Center of Evangelismos Hospital, Athens Medical School, University of Athens. All patients were studied over a period of three consecutive years, during which time clinical and polysomnography (PSG) findings were compared. RESULTS: Body mass index (BMI) was similar in men and women with OSAS (BMI=31.6+/-5.5kg/m(2) in men versus BMI=32.5+/-8.1 (SD) kg/m(2) in women). Female patients were significantly older than male patients (56.9+/-10.6 versus 50.6+/-11.7 year, P=0.001). The mean apnea-hypopnea index (AHI) during total sleep time was higher in men than in women (42.4+/-28.2 versus 33.2+/-27.7 events/h, P<0.001). The AHI in non-rapid eye movement (NREM) sleep was higher in men than in women (42.9+/-28.9 versus 32.6+/-28.7 events/h, P<0.001), but in rapid eye movement (REM) sleep AHI was similar in men and women (36.0+/-23.3 versus 34.9+/-25.4 events/h). Forty percent of men had AHI-REM sleep >AHI-NREM compared to 62% of women, and the difference between REM and NREM-AHI was significantly less in men than in women (14.21+/-11.18 versus 19.76+/-13.43 events/h, P<0.001)). Several aspects of sleep were worse in women versus men: sleep efficiency index was lower (79.4+/-16.1% versus 85.1+/-12.5%, P<0.001); sleep onset latency (27.7+/-27.7 versus 17.9+/-18.1min, P<0.001), and REM onset latency (161.5+/-76.2 versus 145.7+/-71.4min, P<0.018) were longer; wake time after sleep onset (WASO) was also greater in women (42.6+/-46.5 versus 30.7+/-34.9min, P<0.003). CONCLUSIONS: In Greek subjects with OSAS, there was no difference in BMI, and female patients were significantly older than male patients. OSAS was diagnosed in men five times more often than in women. AHI was greater in men than in women, but women are more likely than men to have a higher AHI in REM than NREM. Sleep quality is worse in female than in male patients.

Adolescent↗
PubMed2004

Review article: sleep and its relationship to gastro-oesophageal reflux.

Gastro-oesophageal reflux disease (GERD) is among the most common gastrointestinal conditions in the USA. For most symptomatic patients, reflux events occur during both daytime and night-time hours. Whereas daytime reflux events tend to be frequent but brief, reflux events that occur during sleep are comparatively less frequent but significantly longer. Longer oesophageal acid-clearance and acid-mucosal contact times during sleep are at least partly due to several physiological changes associated with sleep, including dramatic declines in saliva production and frequency of swallowing, decreased conscious perception of heartburn and consequent arousal and clearance behaviours, and slower gastric emptying. Obstructive sleep apnea syndrome and obesity seem to predispose some patients to nocturnal GERD, and the presence of either of these conditions may help to identify patients with symptoms consistent with GERD. Recognition and treatment of night-time GERD are important because it can be associated with decreased quality of life (including sleep disruption) and increased risk of serious oesophageal and respiratory complications.

Circadian Rhythm↗
PubMed2001

Radiofrequency tissue reduction of the palate in patients with moderate sleep-disordered breathing.

OBJECTIVE: Radiofrequency volumetric reduction of the palate has been advocated as a treatment for mild sleep-disordered breathing (SDB). Our study examines the efficacy of this procedure on patients with mostly moderate SDB. DESIGN: Prospective, nonrandomized, consecutive series. SETTING: St. Boniface Hospital, Sleep Disorders Centre, University of Manitoba, Winnipeg. METHOD: Twelve patients with polysomnographically proven moderate SDB were given a total of 2400 to 3600 joules of radiofrequency energy to their soft palate over two to three treatments. Follow-up examined the effect of treatment on subjective and objective parameters including the Epworth Sleepiness Scale, loudness of snoring, Apnea-Hypopnea Index (AHI), and Arousal Index. RESULTS: Two of 12 patients had a good objective response to treatment in that their AHI dropped by more than 50% and to a value of less than 20. However, none of the patients claimed to have a satisfactory subjective response. There was a slight reduction in the mean AHI from 31.2+/-5.1 to 25.3+/-4.2 (p < .05), but no clinically significant difference was found between pre- and post-treatment groups with respect to other sleep parameters. There was no improvement in daytime sleepiness or snoring. CONCLUSIONS: Radiofrequency tissue ablation of redundant soft palate tissues lacks clinical efficacy in patients with moderate SDB.

Adult↗
PubMed1999

Decision making in obstructive sleep-disordered breathing: putting It all together

Obstructive sleep-disordered breathing consists of a spectrum ranging from the upper airway resistance syndrome to complete apnea. Although this disorder is relatively common, it is still under-recognized, resulting in a significant increase in morbidity and mortality. This article describes the rationale for treating this disorder. Then, using the best available evidence, develops a systemic approach to the problem, covering recognition, diagnosis, and treatment.

Journal Article↗
PubMed1998

Effect of pergolide on restless legs and leg movements in sleep in uremic patients.

Restless legs syndrome (RLS) and periodic limb movements in sleep (PLMS) are disorders that are common and disturbing to uremic patients. The treatment of these is problematic. Eight patients on chronic hemodialysis and continuous peritoneal dialysis completed a double-blind placebo-controlled crossover study using incremental doses of pergolide up to 0.25 mg at bedtime for treatment of RLS and sleep disruption. Five patients (62.5%) noted subjective improvement in restless legs symptoms and sleep quality. Objective results were improved only slightly by treatment. The percentage of the first hour in bed during which leg movements occurred decreased from 20.5 +/- 6.0 to 11.5 +/- 3.3, p < 0.05. However, findings during sleep were less positive. The following measures were not significant between placebo and treatment: leg movements per hour of sleep [53.7 +/- 22.3 vs 35.8 +/- 11.8 (p = 0.2)]; and percentage of sleep time spent with leg movements [5.5% +/- 3.2 vs 4.4% +/- 1.4 (p = 0.37)]. Patients continued to have very disrupted sleep, and we could not document an objective improvement in sleep architecture. Thus, although pergolide at the dose of 0.25 mg at bedtime provided subjective improvement in symptoms of restless legs and quality of sleep, and objectively decreased leg movements during the first hour in bed, objectively sleep continued to be disrupted. In this small patient group, the response to pergolide was not uniform, and further investigation is required to test effectiveness at higher doses.

Adult↗
PubMed1998

Decision making in obstructive sleep-disordered breathing. Putting it all together.

Obstructive sleep-disordered breathing consists of a spectrum ranging from the upper airway resistance syndrome to complete apnea. Although this disorder is relatively common, it is still under-recognized, resulting in a significant increase in morbidity and mortality. In this article, we describe the rationale for treating this disorder. Then, using the best available evidence, we try to develop a systemic approach to the problem, covering recognition, diagnosis, and treatment.

Clinical Trials as Topic↗
PubMed1996

Treatment of obstructive sleep apnea with a self-titrating continuous positive airway pressure (CPAP) system.

Conventional manually adjusted continuous positive airway pressure (CPAP) is an effective therapy for sleep-disordered breathing. We prospectively investigated the efficacy of a self-titrating nasal CPAP system in the acute treatment of obstructive sleep apnea (OSA) syndrome. Twenty patients with moderately severe OSA [apnea hypopnea index (AHI) > 15/hour] were enrolled in a randomized, controlled, prospective clinical trial. An initial diagnostic sleep study was performed, followed by randomization to a manually adjusted CPAP titration on one night and self titrating CPAP on the other night. On the conventional CPAP night, the CPAP was manually adjusted until abolition of all apneas and electroencephalographic (EEG) arousals, whereas the self-titrating CPAP was set in automatic mode at lights out. The self-titrating CPAP system utilized an algorithm based on airway vibration patterns to detect airway stability. The AHI decreased from 50.8 +/- 28.8/hour [mean +/- standard deviation (SD)] at baseline to 3.8 +/- 3.1/hour (p < 0.005) during manually adjusted and 6.1 +/- 5.3/hour (p < 0.005) during self-titrating CPAP. The arousal index (Ar-I) decreased from 34.1 +/- 23.1/hour (baseline) to 11.2 +/- 5.0/hour on manual adjustment (p < 0.005) and 11.3 +/- 0.3/hour on self titration (p < 0.005), whereas total sleep time was unchanged. No significant differences in any measure of oxygenation or sleep architecture were observed between the manually adjusted and self-titrating CPAP nights except that the lowest arterial oxygen saturation (SaO2) was higher with manual titration (84.4 +/- 4.2% vs. 79.9 +/- 9.7%, p < 0.05). The maximum pressure required for abolition of apneas and arousals was significantly lower (p < 0.05) during the self-titrating study (10.1 +/- 3.8 cmH2O) as compared to manually adjusted CPAP (12.3 +/- 3.9 cmH2O). Failure to increase pressure and failure to maintain minimum pressure occurred in 7 of the 20 subjects during the self-titrating study. This required manual resetting of the system in five subjects, but the system self-corrected in two subjects. An unsupervised study would have resulted in undertreatment of OSA. Based on a single-night laboratory study, self-titrating CPAP was well tolerated and improved OSA and sleep architecture comparable to manually adjusted CPAP. The future modifications of this prototype will require further research to assess its efficacy and safety in the laboratory and home environments before its recommendation for general long-term use.

Adult↗
PubMed1993

Nocturnal cluster headache associated with sleep apnea. A case report.

We describe a 49-year-old man with chronic cluster headache unresponsive to all medications. Following investigation in the sleep lab he was found to have obstructive sleep apnea (OSA) with associated oxygen desaturations during rapid eye movement (REM) sleep. He awakened during one of these episodes with a typical headache. Treatment with nasal CPAP abolished his OSA and desaturations, and largely abolished his headaches. He then developed central apneas during REM sleep. Further treatment with BiPAP, with a set backup rate, abolished both the apneas and the headaches. We conclude that there may be a link between nocturnal cluster headaches and sleep apnea.

Annexin A2↗
PubMed1993

A developmental study of the dose-response curve of the respiratory sensory reflex.

We have shown previously that inhalation of high concentration of CO2 (about 8%) inhibits breathing in preterm infants, presumably through an upper airway sensory reflex. To study the developmental aspects and the dose-response curve of this reflex, we studied eight preterm infants (body weight, 1.6 +/- 0.1 kg mean +/- SE; gestational age, 31 +/- 1 wk; postnatal age, 22 +/- 5 days) and eight term infants (body weight, 3.2 +/- 0.1 kg; gestational age, 39 +/- 1 wk; postnatal age, 8 +/- 6 days) using a flow-through system; eight adult subjects (weight, 67 +/- 5 kg; age, 30 +/- 4 yr) were studied during quiet sleep using a nasal mask. We gave 2, 4, 6, and 8% CO2 in 21+ O2 randomly for 20 to 30 s. A clear inhibition of breathing typically occurred during inhalation of 8% CO2 only in preterm infants, as reflected by the presence of an apnea of 11 +/- 1 s occurring at 7 +/- 2 s after the beginning of CO2 inhalation. Short apneas were occasionally observed with lower concentrations of CO2, but they were significantly fewer and shorter than with 8% CO2. No clear inhibition was observed in term infants or adult subjects, but pauses of 4 and 6 s were observed in the former group and a pause of 7 s was observed in the latter one. The associated changes in minute ventilation during inhalation of 2, 4, and 6% CO2 were not significantly different between the three groups. During inhalation of 8% CO2, minute ventilation decreased only in preterm infants (-26 +/- 10 compared with +32 +/- 10 in term infants and to +17 +/- 5% in adult subjects; p = 0.003 between groups).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

The effect of short-term nasal CPAP on Cheyne-Stokes respiration in congestive heart failure.

We studied male patients (BMI = 27.6 +/- 3.4, mean +/- SD), mean age 54.1 +/- 8.9 years, with stable NYHA class 3-4 congestive heart failure (CHF) (LVEF = 24.3 +/- 11.5 percent) and normal daytime arterial blood gas values. These patients underwent three consecutive nights of full polysomnography; adaptation, control, and treatment with nasal CPAP. Each night's study was followed during the day by cognitive testing and multiple sleep latency tests (MSLT). The purpose of the study was to document the effect of nasal CPAP on these variables. The main findings of the study showed no significant differences between control and treatment nights with respect to the amount of Cheyne-Stokes respiration (CSR) observed, the nocturnal oxygenation, or sleep quality. Both subjective and objective measures of sleep quality showed no change from night to night. In addition, the degree of cognitive functioning and daytime sleepiness (as measured by MSLT) showed no significant differences between control and treatment nights. We conclude that short-term treatment with nasal CPAP in patients with CHF does not improve either CSR, nocturnal oxygenation, or sleep quality. Furthermore, most of our patients did not tolerate nasal CPAP therapy.

Adult↗
PubMed1992

The importance of nasal resistance in obstructive sleep apnea syndrome.

The importance of nasal airflow resistance in the pathogenesis of obstructive sleep apnea syndrome (OSAS) remains contentious. We performed formal nocturnal polysomnography (PSG) on OSAS patients under conditions of baseline and reduced nasal resistance to answer two main questions. First, to what degree does baseline nasal airflow resistance influence upper airway collapse in OSAS patients? Second, in what proportion of the OSAS population is baseline nasal resistance contributing to the pathogenesis of upper airway collapse? Our study group consisted of 10 patients with a wide range of OSAS severity. Six of these patients had symptoms and clinical evidence of chronic nasal obstruction which, in some, was associated with markedly elevated nasal resistance. A placebo (normal saline) was instilled in the nose of each patient on the night of baseline data collection. On the treatment night of the study, nasal resistance was reduced by application of topical vasoconstrictor and insertion of vestibular stents designed to dilate the area of the nasal valve. Posterior rhinomanometry was used to measure resistance to nasal airflow immediately before and after each PSG study. Although treatment was associated with a subjective improvement in sleep quality and mean drop in nasal resistance of 73% (P less than 0.001), there was no significant improvement in sleep architecture, nocturnal oxygenation, or the amount of apnea experienced by patients. The most significant improvement was a reduced number of arousals/hour from 52.4 +/- 12.4 on placebo to 43.7 +/- 10.2 on treatment (P less than 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Sleep quality in children with asthma treated with theophylline or cromolyn sodium.

The effect of theophylline and cromolyn sodium on sleep was studied in 10 children with asthma who were 10 to 17 years of age (mean 13.5 +/- 2.4 years). Theophylline or cromolyn sodium was taken for 14 days in a double-blind, crossover, placebo-controlled trial. Theophylline blood levels before sleep were 10.2 +/- 4 micrograms/ml during the theophylline period. There was no difference in pulmonary function between the two periods. Theophylline did not disrupt sleep as measured by sleep latency, total sleep time, sleep efficiency, movement time, microarousals, and arousals. Apneic episodes (greater than or equal to 10 seconds) were of central origin and less frequent during the theophylline period (p less than 0.05). Arterial oxygen desaturation (greater than 5% decrease from baseline saturation when awake) was less frequent during the theophylline treatment (p less than 0.05). We conclude that theophylline treatment of the children's asthma did not disrupt sleep and appeared to have a protective effect in regard to apnea, hypopnea, and arterial oxygen saturation.

Adolescent↗