Oxygen desaturation during sedation for colonoscopy in elderly patients

BACKGROUND/AIMS: Conscious sedation increases the tolerance of patients to endoscopic examination, but arterial oxygen desaturation during endoscopy has often been reported. Elderly patients are considered to be at special risk. However, sedation-induced changes in cardiovascular function in the elderly have not been well investigated. Therefore, this study examined the effects of sedation on pulse rate, systolic blood pressure, and arterial oxygen saturation in elderly patients. METHODOLOGY: Twenty patients aged less than 60 years and 20 patients aged 60 years or more, scheduled to undergo colonoscopic removal of colorectal polyps, received 0.05 or 0.025 mg/kg body weight, respectively, of midazolam intravenously. Before, during, and after endoscopy, pulse rate, systolic blood pressure, and arterial oxygen saturation were recorded every 5 min with a pulse oximeter. RESULTS: Administration of midazolam had no significant effect on pulse and arterial systolic blood pressure in either group. In contrast, midazolam significantly reduced the levels of arterial oxygen saturation during and after endoscopy in both age groups. However, although patients aged 60 years or more received midazolam at half dosage, arterial oxygen saturation during endoscopy was significantly lower and the incidence of 5% or more oxygen desaturation was significantly higher than in the patients aged less than 60 years. CONCLUSIONS: Midazolam increases the tolerance of elderly patients to endoscopy, but it significantly lowers the level of arterial oxygen saturation and increases the incidence of desaturation. Continuous monitoring is especially valuable during endoscopy in the elderly.     

Polyneuropathy in patients with periodic leg movements during sleep

INTRODUCTION: Periodic legs movements of sleep (PLMS) are rhythmic, standard and repetitive contractions of muscles of the extremities during the sleep. It is known that the patients with restless legs syndrome (RLS) have disorders during the sleep: increase in the latency of the sleep, increased number of arousal, etc.; most of them have also periodic movements of the legs during the sleep. OBJECTIVE: The relationship of the periodic movements of the legs during the sleep with polyneuropathy is not clear. Some authors have found evidence of electrophysiological and pathological of signs of axonal mild polyneuropathy in patients with restless legs syndrome. In this work, we evaluated nine patients that were diagnosed of PLMS, to determine the prevalence of neuropathy in such sample. METHOD: Polysomnography of nocturnal sleep of 7-8 hours was performed, including electromyographic recording of both anterior tibialis muscles; and electroneurographic study of peroneal, sural, ulnar and median nerves. DISCUSSION: Just in none of the nine studied cases were obtained electrophysiological signs of neuropathy; though it has been able to demonstrate the existence of mild alteration of the peripheral nervous system, fundamentally of sensory character; nevertheless, C we think that it would have to be studied the existence of polyneuropathy in all the patients with PLMS in order to discard potentially tractable organic causes.     

Utility of nocturnal home oximetry for case finding in patients with suspected sleep apnea hypopnea syndrome

OBJECTIVE: To evaluate prospectively the validity of home oximetry for case finding in patients clinically suspected of having the sleep apnea hypopnea syndrome (SAHS). DESIGN: Blinded comparison of home oximetry and polysomnographic nocturnal recordings. SETTING: Sleep clinic of a tertiary referral center. PATIENTS: A total of 240 outpatients referred because of reported sleep disturbances or daytime hypersomnia compatible with the diagnosis of SAHS. MEASUREMENTS: All participants had nocturnal home oximetry followed by a conventional polysomnographic study. The two recordings were interpreted blindly. Home oximetry test results were classified as abnormal (suspicion of sleep-related breathing abnormalities) in the presence of repetitive, short-duration arterial oxyhemoglobin saturation. (SaO2) fluctuations without any absolute or relative decrease in the SaO2 threshold. The diagnosis of SAHS was confirmed when the apnea-plus-hypopnea index was greater than 10. RESULTS: Based on the results of the polysomnographic sleep study, 110 patients had SAHS (apnea-plus-hypopnea index, 38.1 +/- 2.5/h; mean +/- SE). Home oximetry test results were interpreted as abnormal in 176 patients (this included 108 patients with SAHS and 68 without SAHS) and were read as normal in 62 patients without SAHS and in 2 with SAHS. Home oximetry testing had a sensitivity of 108/110 or 98.2% (95% Cl, 93.6% to 99.8%); a specificity of 62/130 or 47.7% (Cl, 38.8% to 56.6%); a positive predictive value of 108/176 or 61.4%; and a negative predictive value of 62/64 or 96.9%. CONCLUSIONS: A negative home oximetry test result is helpful in ruling out the diagnosis of SAHS in patients clinically suspected of having this syndrome, because a negative test result reduced the probability from 54.1% to 3.1% in our patients. However, a positive oximetry test increased the probability from 46% to 61.4% in our group of patients.     

Twenty-four-hour ambulatory oxygen desaturation and electrocardiographic recording in obstructive sleep apnea syndrome

BACKGROUND: Although nocturnal pulseoximetry is routinely performed in obstructive sleep apnea syndrome (OSAS), pulseoximetry over a 24-h period has not been studied. HYPOTHESIS: The purpose of the study was to determine whether simultaneous 24-h oxygen desaturation and electrocardiographic (ECG) recording might be used to screen for daytime sleep sequelae in patients with OSAS. METHODS: Simultaneous recording of arterial oxygen saturation (SpO2) and ECG was conducted over a 24-h period in 18 male patients with OSAS (mean age 51.3 years) who were diagnosed by standard polysomnography (PSG), and in 15 age-matched healthy subjects (mean age 52.7 years) as controls to evaluate circadian variation of these parameters. The measures of heart rate variability (HRV) were calculated from 24-h ambulatory ECGs. Seventeen patients with OSAS showed excessive daytime sleepiness (EDS). We calculated the duration in which SpO2 decreased to < 90% (duration of SpO2 < 90%). The number of apnea/hypopneas per hour (AHI) during sleep was investigated with Apnomonitors (Chest MI, Co., Tokyo) on the same day as the SpO2 recordings. RESULTS: Controls showed no episodes of oxygen desaturation. In patients with OSAS, driving (33.3% of patients with OSAS) was the most common activity in which SpO2 decreased to < 90%, followed by daytime napping (27.8%) and resting after meals (22.2%). The duration of SpO2 < 90% over a 24-h period correlated significantly with the duration levels recorded during sleep (r = 0.99, p < 0.05) and in the afternoon (r = 0.62, p < 0.05), and with the AHI (r = 0.55, p < 0.05), but not with the duration of SpO2 < 90% in the morning. The number of ventricular premature beats correlated significantly with the duration of SpO2 < 90% for a 24-h period, but not with measures of HRV. Ventricular tachycardia was found in two (11.1%) and ST-T depression in three patients (16.6%) with underlying cardiac diseases. CONCLUSION: Our results suggest that daytime sleep attacks accompanied by oxygen desaturation in patients with moderate to severe OSAS may contribute to the occurrence of traffic or cardiovascular accidents. We conclude that 24-h ambulatory recordings of SpO2 and ECG are useful for screening for daytime sleep sequelae associated with the potential risk of this pathology in OSAS during social activities.     

Daytime melatonin infusions induce sleep in pigeons without altering subsequent amounts of nocturnal sleep

Magnetic retention devices based on cobalt/samarium alloy are new to dentistry, whereas precision attachments have been used for many years. In this study, the retentive forces of two magnetic systems were compared with two different precision attachment units. The retentive forces were evaluated with an Instron testing machine with a cross-head speed of 0.5 mm/min. Eight samples were used for each of the four attachments for a total of 32 samples. The attachments were embedded in an acrylic block and tested for initial retention and retention after 300 cycles. The retentive forces of the precision attachments were greater than the magnetic attachments for the initial retention. However, as more cycles were completed, the retentive force decreased in the precision attachments and increased in the magnetic attachments. The results were statistically significant among the four attachment systems (p = 0.0117).     

Periodic breathing during sleep at high altitudes in patients with bronchial asthma

Earlier we found that asthmatic patients treated at a high altitude sanatorium (3.200 m) had numerous episodes of arterial blood desaturation during the night. To investigate if periodic breathing (PB) was responsible for those episode we studied 5 asthmatics (A) (mean age 34 yrs) and 3 healthy controls (C) (mean age 28 yrs) using MESAM 4, a simple, portable system recording breathing sounds, heart frequency, arterial blood saturation and body position. A and C subjects were first investigated at low altitude (760 m). There was no PB at 760 m in either group. At high altitude MESAM 4 recordings were performed on the 2nd and the 7th night after the ascent. On the 2nd night in the A group subjects the number of PB cycles averaged 37.2 (22-54) occupying 3.2% (2-5%) of estimated sleep time. The number of no-PB episodes was 52.4 (23-109). In the C group subjects the number of PB cycles was 83.6 (10-147) occupying 9% (1-14%) of estimated sleep time. The number of no-PB episodes averaged 45.6 (6-84). On the 7th night in A the number of PB cycles was 46.6 (15-69) occupying 4% (1-7%) of estimated sleep time. The number of no-PB was 54.8 (13-147). In C the number of PB cycles averaged 29.3 (12-59) occupying 3.3% (2-6%) of estimated sleep time. The number of no-PB was 20.3 (9-37). We conclude that majority of desaturations during sleep in asthmatics at altitude of 3.200 m was not related to PB; the mechanisms of these desaturations require more investigations.     

Influence of sleep apnea on nocturnal blood pressure

In the present study, we subjected 65 patients to overnight monitoring and continuous nocturnal blood pressure measurement in order to assess the influence of sleep apnea on the circulatory system. Thirty-one patients were compared before and after surgery. The severity of sleep apnea was classified by Apnea Hypopnea Index (AHI), the duration of exposure to low-level oxygen (calculated as the desaturation time: DT), and increment of blood pressure. Before surgery, a significant correlation was noted between the DT and blood pressure changes. Therefore, this index was considered useful for assessing the influence of sleep apnea on nocturnal blood pressure. After surgery, improvement of AHI was greater than 50% in 19/31 patients (61.3%), and this result was almost the same as described in the literature. The improvements in DT and BP change were greater than 50% in 21/31 (67.7%) and 14/31 (45.2%), respectively. With regard to severity before surgery, AHI was > or = 50 and DT was > or = 40% in 10 and 18 patients, respectively. Nineteen patients had BP changes > or = 40 mmHg. After surgery, 1,5, and 2, patients, respectively, still showed these values. Thus, a beneficial effect of surgery was demonstrated.     

Left ventricular volume in patients with heart failure and Cheyne-Stokes respiration during sleep

In patients with congestive heart failure (CHF), elevated, left ventricular (LV) volume might lead to pulmonary congestion and hypocapnia, which would create a predisposition to the development of Cheyne-Stokes respiration with central sleep apnea (CSR-CSA). In addition, because LV volume affects cardiac output, it should influence the lengths of hyperpneas. We therefore evaluated LV volumes and transcutaneous PCO2 (PtcCO2) during wakefulness and stage 2 sleep in 16 patients with CHF due to nonischemic dilated cardiomyopathy (NIDC). Data were then compared between those with (n = 7) and those without CSR-CSA (n = 9). LV end-diastolic volume (LVEDV) was significantly higher in patients with than those without CSR-CSA (585 +/- 118 versus 312 +/- 41 ml, p < 0.05). Compared with patients without CSR-CSA, those with CSR-CSA had lower mean stage 2 sleep PtcCO2 (36.3 +/- 2.2 versus 41.2 +/- 1.2 mm Hg, p < 0.05) and a lesser change in PtcCO2 from wakefulness to stage 2 sleep (-0.4 +/- 0.3 versus 2.0 +/- 0.4 mm Hg, p < 0.001). Among patients with CSR-CSA, hyperpnea length was inversely related to LVEDV (R = 0.769, p = 0.043) owing to the direct relationship of cardiac output to LVEDV (R = 0.791, p = 0.034). We conclude that CSR-CSA in patients with CHF due to NIDC is associated with increased LV volumes possibly through the direct or indirect influence of LV volume on PaCO2 and cardiac output.     

Paroxysmal nocturnal haemoglobinuria clones in patients with myelodysplastic syndromes

Among acquired stem cell disorders, pathological links between myelodysplastic syndromes (MDS) and aplastic anaemia (AA), and paroxysmal nocturnal haemoglobinuria (PNH) and AA, have been often described, whereas the relationship between MDS and PNH is still unclear. We analysed blood cells of patients with MDS to determine the incidence of the PNH clone, and analysed the PIG-A gene to find mutations characteristic of the PNH clone in MDS. In four (10%) of 40 patients with MDS, flow cytometry showed affected erythrocytes and granulocytes negative for decay-accelerating factor (DAF) and CD59. The population of affected erythrocytes was smaller in MDS patients with PNH clone (MDS/PNH) than in patients with de novo PNH, and haemolysis was milder in the MDS/PNH patients. PIG-A mutations were found in granulocytes of all patients with MDS/PNH. In type and site, the PIG-A mutations were heterogeneous, similar to that observed in de novo PNH; i.e. no mutation specific to MDS/PNH was identified. Of note, three of four patients with MDS/PNH each had two PNH clones with different PIG-A mutations, suggesting that PIG-A is mutable in patients with MDS/PNH. In a MDS/PNH patient with trisomy 8, FISH detected a distinct karyotype in a portion of granulocytes with PNH phenotype, indicating that PNH and MDS partly shared affected cells. Thus, MDS predisposes to PNH by creating conditions favourable to the genesis of PNH clone. Considering the increasing prevalence and incidence of MDS, these disorders could be useful for investigating the mechanism by which PIG-A mutation is induced.     

Does mixed venous desaturation during a bed bath indicate cardiopulmonary decompensation in postoperative cardiac patients?]

The bed bath procedure consists of cleansing patients' body, passive position change, changing gown and making a bed. During the procedure, mixed venous desaturation was observed consistently in postoperative cardiac patients. We investigated the cause of the phenomenon in 22 patients undergoing cardiac surgery in their first postoperative day. The patients were breathing oxygen-enriched air via a Venturi mask. Cardiac index (CI), transluminal SvO2, arterial blood gas, Hb, DO2, VO2, FIO2, A-aDO2 and Qp/Qs were measured before and during the bed bath, while the patients were in the supine and left lateral position, respectively. Mean 8.5 +/- 1.5 minutes were required to complete the bed bath. During the bed bath, SvO2 decreased from 71 +/- 7% to 59 +/- 9% (P < 0.001), and returned to the baseline 6.5 +/- 7.4 minutes after the completion of the bed bath. VO2 increased markedly from 128 +/- 27 to 194 +/- 47 ml.min-1.m-2 (P < 0.001), while DO2 increased slightly from 480 +/- 91 to 513 +/- 110 ml.min-1.m-2 (P < 0.05). Among the determinants of DO2, CI increased slightly from 3.3 +/- 0.6 to 3.6 +/- 0.8 l.min-1.m-2, Hb remained unchanged and SaO2 decreased from 98.5 +/- 0.8 to 98.0 +/- 1.1%. FIO2 also decreased, while A-aDO2 and Qp/Qs remained unchanged. There was a negative correlation between VO2 change and SvO2 change, but no correlation between DO2 change and SvO2 change. There was a positive correlation between SaO2 change and SvO2 change, as well as between FIO2 change and SaO2 change. Therefore, the major cause of mixed venous desaturation was not the decreased DO2 or cardiopulmonary decompensation but the increased VO2 due to increased activity of the skeletal muscles. However, the decrease in SaO2 due to markedly increased O2 demand and the limited increase in CI might partially contribute to the marked decline in SvO2 through the limited increase in DO2.     

Anamnestic and polygraphic parameters in obstructive sleep apnea syndrome patients with reduced nasal respiration during the day in comparison with obstructive sleep apnea patients with normal nasal respiration

Nasal obstruction is a predictive factor for snoring and may contribute to the development of an obstructive sleep apnea syndrome (OSAS). The aim of this study was to further evaluate the impact of nasal obstruction in OSAS. Therefore, we investigated 2 groups of OSAS-patients, matched pairs concerning gender, age, and BMI: OSAS-patients with nasal obstruction (N, n = 28), total nasal airflow < 500 ccm/s (referred to 150 pa pressure of difference or unilateral nasal resistance > 1 pa/ccm/s), and 28 OSAS-patients without nasal obstruction (control-group K, total nasal airflow > 700 ccm/s [referred to 150 pa pressure of difference or unilateral nasal resistance > 1 pa/ccm/s]). We performed anterior rhinomanometry, lung-function testing, cardio-respiratory polygraphy, and patients answered a standardized questionnaire. We found the following significant differences: 1) N complained more often (n = 17) about dyspnea at night than K (n = 7, p < 0.05, Chi2-test). 2) N had a higher apnea index (20.4 +/- 19.0/h) than K (9.6 +/- 10.0/h, p < 0.05, Student's t-test). There were, however, no significant differences concerning lung function, number of nocturnal hypopneas, nocturnal SaO2 and heart rate. Our results underline the importance of nasal ventilation in the pathogenesis of OSAS. At least in moderate cases of OSAS a therapy of nasal obstruction might be of success in order to abolish nCPAP-therapy or might reduce nasal problems during nCPAP-therapy and thus ameliorate patient's therapy compliance.     

Elevated nocturnal profiles of serum leptin in patients with depression

Leptin, the protein product of the obese (ob) gene, has been suggested to play a role in the regulation of food intake. As depressive episodes are frequently characterized by loss of appetite, reduced food intake and weight loss, altered leptin secretion might also be expected in patients with depression. Therefore, we examined nocturnal (10.00 p.m. to 7.00 a.m.) secretion of leptin, cortisol, ACTH and growth hormone (GH) in a group of 15 patients with depression and age- and sex-matched controls (age range 23-71 years). In addition, the effects of pulsatile administration of growth hormone-releasing hormone (GHRH), thought to be an endogenous antagonist of corticotropin-releasing hormone (CRH), which in turn is believed to play a critical role for the pathophysiology of depression, on nocturnal hormone secretion were assessed. Patients with depression showed a trend towards elevated nocturnal cortisol secretion (F = 3.8, p < 0.05). Nocturnal serum leptin was significantly higher in patients, despite a reported weight loss (F = 8, p < 0.05), but showed the same sexual dimorphism as in controls (F = 20.9, p < 0.01). No significant differences were seen between patients and controls with regard to plasma GH and ACTH. GHRH treatment increased GH secretion in both patients and controls, while the other hormones were not affected. Furthermore, serum leptin was correlated with body mass index (BMI) in controls, but not in patients with depression, supporting an altered regulation of leptin secretion in depressive illness. Finally, we provide some evidence that in young female patients the normal nocturnal leptin surge is blunted. As glucocorticoids can prevent the fasting-induced decline in serum leptin, we propose that hypercortisolism in depression might counteract the reduction in leptin secretion caused by decreased food intake and weight loss. Elevated serum leptin in depression might in turn further promote CRH release, as shown in animals and, hence, contribute to HPA system hyperactivity seen in depression.     

Changes in EEG power density of non-REM sleep in depressed patients during treatment with trazodone

Recently, it was hypothesized that acute or cumulative suppression of non-REM sleep intensity might be related to the therapeutic effects of antidepressants. This intensity has been proposed to be expressed in the EEG power density in non-REM sleep. In the present study, the relationship was examined between the changes of EEG power density in non-REM sleep and the changes in clinical state in 8 depressed patients during treatment with trazodone. A 1-week wash-out period was followed by 1 week of placebo administration, a medication period of 5 weeks and a 1-week placebo period. To minimize systematic influences of sleep duration and non-REM-REM sleep alterations, EEG power was measured over the longest common amount of non-REM sleep stages 2-4 (168.5 min), accumulated from sleep onset onwards. During trazodone treatment, the 13- and 14-Hz bins showed a significant reduction in EEG power. No clear-cut change, however, was observed in the EEG power of the delta frequency range (1-4 Hz) which is considered to be the principle manifestation of non-REM sleep intensity. Furthermore, no overall significant relationship between EEG power suppression and clinical improvement could be demonstrated.     

Dreams recalled spontaneously following afternoon naps and nocturnal sleep.

Obtained 2 spontaneously recalled dreams from each of 37 undergraduates, 1 following a normal 8 hr. Of nocturnal sleep and 1 subsequent to an afternoon nap. The nap dreams were significantly less aggressive (p     

Sleep-related O2 desaturation and daytime pulmonary haemodynamics in COPD patients with mild hypoxaemia

It has been hypothesized but not firmly established that sleep-related hypoxaemia could favour the development of pulmonary hypertension in chronic obstructive pulmonary disease (COPD) patients without marked daytime hypoxaemia. We have investigated the relationships between pulmonary function data, sleep-related desaturation and daytime pulmonary haemodynamics in a group of 94 COPD patients not qualifying for conventional O2 therapy (daytime arterial oxygen tension (Pa,O2) in the range 7.4-9.2 kPa (56-69 mmHg)). Nocturnal desaturation was defined by spending > or = 30% of the recording time with a transcutaneous O2 saturation < 90%. An obstructive sleep apnoea syndrome was excluded by polysomnography. Sixty six patients were desaturators (Group 1) and 28 were nondesaturators (Group 2). There was no significant difference between Groups 1 and 2 with regard to pulmonary volumes and Pa,O2 (8.4+/-0.6 vs 8.4+/-0.4 kPa (63+/-4 vs 63+/-3 mmHg)) but arterial carbon dioxide tension (Pa,CO2) was higher in Group 1 (6.0+/-0.7 vs 53+/-0.5 kPa (45+/-5 vs 40+/-4 mmHg); p<0.0001). Mean pulmonary artery pressure (Ppa) was very similar in the two groups (2.6+/-0.7 vs 2.5+/-0.6 kPa (19+/-5 vs 19+/-4 mmHg)). No individual variable or combination of variables could predict the presence of pulmonary hypertension. It is concluded that in these patients with chronic obstructive pulmonary disease with modest daytime hypoxaemia, functional and gasometric variables (with the noticeable exception of arterial carbon dioxide tension) cannot predict the presence of nocturnal desaturation; and that mean pulmonary artery pressure is not correlated with the degree and duration of nocturnal hypoxaemia. These results do not support the hypothesis that sleep-related hypoxaemia favours the development of pulmonary hypertension.     

Intraoperative jugular desaturation during surgery for traumatic intracranial hematomas

Traumatic intracranial hematomas which are present on hospital admission or which develop during the hospital course are associated with a worse neurological outcome than diffuse injuries. The purpose of this study was to monitor jugular venous oxygen saturation (Sjvo2) during surgery for evacuation of traumatic intracranial mass lesions, to determine the incidence and the causes of jugular venous desaturation, and to assess the usefulness of Sjvo2 monitoring in this setting. Twenty-five severely head injured patients were monitored during 27 surgical procedures. At the start of the surgical procedure, the median Sjvo2 was 47% (range 25%-89%). Seventeen (63%) of the patients had a Sjvo2 less than 50%. Five patients had extremely low Sjvo2 values (< or = 30%). Upon evacuation of the intracranial hematoma, there was a significant (P < 0.001) increase in the median Sjvo2 to 65% (range 50%-88%). Intracranial hypertension was the primary cause of the low Sjvo2, as confirmed by the response to surgical evacuation. Hypotension (mean arterial pressure < 80 mm Hg) was a contributing factor in seven of the cases of jugular desaturation. The definitive treatment of a traumatic intracranial hematoma is surgical evacuation. However, during the period prior to evacuation of the hematoma, jugular venous desaturation was common, suggesting that monitoring Sjvo2 might provide useful information about the adequacy of cerebral perfusion.     

Arterial oxygen desaturation during non-sedated diagnostic upper gastrointestinal endoscopy

We studied oxygen saturation (SaO2) using a pulse oximeter in 120 patients undergoing non-sedated diagnostic upper gastrointestinal endoscopy. The baseline SaO2 was 98.3 +/- 1.0%. During the procedure, absence of oxygen desaturation (SaO2 > or = 95%) was found in 56%, mild oxygen desaturation (95% > SaO2 > or = 90%) in 35%, and severe oxygen desaturation (SaO2 < 90%) in 9%. Age (p = 0.56), gender (p = 0.47), smoking (p = 0.35), hemoglobin level (p = 0.52), body mass index (p = 0.27), or total endoscopy time (p = 0.72) was not related to the degree of oxygen desaturation. These results suggest that oxygen desaturation is frequently observed during non-sedated diagnostic upper gastrointestinal endoscopy although severe oxygen desaturation, which may induce rare but serious cardiopulmonary events, is not common. Furthermore, we cannot predict in which patients desaturation will occur. We therefore recommend continuous monitoring of arterial oxygenation in all patients during the procedure.     

Upper airway muscle activity during REM and non-REM sleep of patients with obstructive apnea

We measured electromyograms (EMGs) of genioglossus muscle (GG) and inspiratory intercostal muscle (IIM) in both rapid eye movement (REM) sleep and non-REM sleep of 12 patients with obstructive sleep apnea (OSA) to examine the influence of different sleep stages on upper airway muscle activity during sleep apnea. Quantifications of both muscle activities were assessed by their individual peak amplitude of integrated inspiratory EMG. Genioglossus and IIM activities showed a qualitatively similar cyclic change with an alteration of apneic and ventilatory phases during both non-REM and REM sleep. Both muscle activities increased gradually in the late apneic phase and reached each peak at the opening of the upper airway and, subsequently, decreased gradually. There were no significant differences in both muscles activities in either the ventilatory or early apneic phase between non-REM sleep and REM sleep. On the other hand, GG and IIM activities in the late apneic phase during REM sleep were significantly lower than those during non-REM sleep. The relative activity of GG to IIM in the late apneic phase was significantly lower during REM sleep than that during non-REM sleep. These results indicate that upper airway and intercostal muscle activation in the later apneic phase during REM sleep were inhibited compared with those during non-REM sleep and that this inhibition was observed predominantly in upper airway muscles.     

Enhanced slow wave sleep in patients with prolactinoma

Bidirectional interactions between nocturnal hormone secretion and sleep regulation are well established. In particular, a link between PRL and rapid eye movement (REM) sleep has been hypothesized. Short-term administration of PRL and even long-term hyperprolactinemia in animals increases REM sleep. Furthermore, sleep disorders are frequent symptoms in patients with endocrine diseases. We compared the sleep electroencephalogram of seven drug-free patients with prolactinoma (mean PRL levels 1450 +/- 1810 ng/mL; range between 146 and 5106 ng/mL) with that of matched controls. The patients had secondary hypogonadism but no other endocrine abnormalities. They spent more time in slow wave sleep than the controls (79.4 +/- 54.4 min in patients vs. 36.6 +/- 23.5 min in controls, P < 0.05). REM sleep variables did not differ between the samples. Our data suggest that chronic excessive enhancement of PRL levels exerts influences on the sleep electroencephalogram in humans. Our result, which seems to be in contrast to the enhanced REM sleep under hyperprolactinemia in rats, leads to the hypothesis that both slow wave sleep and REM sleep can be stimulated by PRL. These findings are in accordance with reports of good sleep quality in patients with prolactinoma, which is in contrast to that of patients with other endocrine diseases.