Thyroid Hormone Levels and TSH Activity in Patients with Obstructive Sleep Apnea Syndrome.

Obstructive sleep apnea syndrome (OSAS) is characterized by complete cessation of inspiratory flow (apnea) or upper airway airflow limitation (hypopnea) with increased respiratory muscle activity, which is repeatedly observed during sleep. Hypothyroidism has been described as a rare cause of OSAS, but it is considered to be the main cause of breathing disorders during sleep in patients in whom an improvement of OSAS is observed after thyroid hormone replacement therapy. Nevertheless, euthyreosis due to thyroxine replacement in patients with OSAS often does not improve the breathing disorder and treatment with continuous positive airway pressure is usually applied. The aim of this study was to assess thyroid function in patients with OSAS. We studied 813 patients in whom severe OSAS was diagnosed; the mean apnea-hypopnea index was 44.0. Most of the patients were obese (mean BMI 33.1 ± 6.6 kg/m2) and had excessive daytime sleepiness (ESS 12.8 ± 6.6). With the thyroid stimulating hormone (TSH) concentration as the major criterion, hypothyroidism was diagnosed in 38 (4.7%) and hyperthyroidism was diagnosed in 31 (3.8%) patients. Analysis of basic anthropometric data, selected polysomnography results, and TSH, fT3, and fT4 values did not reveal any significant correlations. In conclusion, the incidence of thyroid function disorders seems to be no different in OSAS than that in the general population. We did not find correlations between TSH activity and the severity of breathing disorders during sleep.

The effect of fiberoptic bronchoscopy on exhaled nitric oxide.

Nitric oxide has been extensively studied as a noninvasive marker of airway inflammation. Assuming that bronchoscopy can produce not only systemic but also local inflammatory response, we hypothesized that bronchofiberoscopy can be responsible for an increase in nitric oxide synthesis with resulting increase in fractional concentration of exhaled nitric oxide (FE(NO)). Fifty five subjects (F/M-23/32; mean age 53.9 +/-17.3 yr) undergoing diagnostic bronchoscopy participated in the study. The indications for bronchoscopy were as follows: interstitial lung diseases (n=13; 23.6%), lung cancer (n=11; 20.0%), hemoptysis (n=10; 18.2%), differential diagnosis of asthma/dyspnea (n=9; 16.4%), pulmonary infections (n=7; 12.7%), and others (n=5; 9.1%). During bronchoscopy bronchial washing (n=18), bronchoalveolar lavage (BAL) (n=26), and bronchial biopsies (n=24) were performed. FE(NO) was analyzed on-line with chemiluminescence analyzer (NIOX, Aerocrine, Sweden) according to the ATS guidelines, before and at 1, 2, 3 and 24 h after bronchoscopy. The mean FE(NO) before bronchoscopy was 21.0 +/-3.31(SE) ppb, it decreased to 14.8 +/-2.10 ppb 1 h after bronchoscopy, reached a nadir at 2 h (14.4 +/-2.28 ppb; P<0.05), and was not different from baseline 24 h after bronchoscopy (22.8 +/-2.90 ppb). There were no differences in the FE(NO) profile in BAL patients compared with those in whom only the bronchial washing was performed. We conclude that bronchoscopy leads to a decrease in FE(NO). The underlying mechanisms are at present unclear.

Observer variations in short period spectral analysis of heart rate variability.

25% of the corresponding mean LF/HF ratio. The smallest interobserver variations were found for the 'fixed frequency' method. The data showed that it is advantageous to select the 3-min ECG periods but not to select the frequency regions. Selection of the latter led to an increase in interobserver variation. The results of this study give a realistic impression of the intrasubject and interobserver variation to be expected when measuring the LF/HF ratio. This variation is considerable.

Hemodynamic patterns and spectral analysis of heart rate variability during dialysis hypotension.

Intradialytic hypotension, a major source of morbidity during hemodialysis and ultrafiltration, is often accompanied by paradoxical bradycardia. Relatively little is known about the sequential changes in autonomic nervous system activity up to and during the hypotensive episode. Continuous, beat-to-beat measurements of BP and heart rate were made during hemodialysis in patients prone (n = 8) and not prone (n = 11) to develop intradialytic hypotension. Off-line spectral analysis of heart rate variability (HRV) was performed to assess changes in autonomic nervous system activity during dialysis sessions both with and without hypotension. The low frequency (LF) component of HRV is thought to correlate with sympathetic nervous system activity, the high frequency (HF) component with that of the parasympathetic nervous system. In the sessions not complicated by symptomatic hypotension (n = 26), mean arterial BP (MAP) hardly fell, whereas heart rate increased from 77 +/- 2 to 89 +/- 5 bpm (P < 0.05). The LF component of HRV increased from 45.2 +/- 5.0 normalized units (nu) to 59.9 +/- 4.9 nu (P < 0.05), whereas the HF component fell from 54.8 +/- 5.0 to 40.2 +/- 4.4 nu (P < 0.05). These changes agree with compensatory baroreflex-mediated activation of the sympathetic nervous system (and suppressed parasympathetic activity) during ultrafiltration-induced intravascular volume depletion. In the sessions complicated by severe symptomatic hypotension (n = 22), the changes in heart rate and the results of spectral analysis of HRV were similar to those reported above up to the moment of sudden symptomatic (nausea, vomiting, dizziness, cramps) hypotension, whereas MAP had already fallen gradually from 94 +/- 3 to 85 +/- 3 mmHg (P < 0.05). The sudden further reduction in MAP (to 55 +/- 2 mmHg, P < 0.02) was invariably accompanied by bradycardia (heart rate directly before hypotension 90 +/- 2 bpm, during hypotension 69 +/- 3 bpm, P < 0.002). The LF component of HRV fell from 62.8 +/- 4.6 nu directly before to 40.0 +/- 3.7 nu (P < 0.05) during hypotension, whereas the HF component increased from 37.9 +/- 4.7 to 60.3 +/- 3.7 nu (P < 0.05). These findings agree with activation of the cardiodepressor reflex, involving decreased sympathetic and increased parasympathetic nervous system activity, respectively. These findings indicate that activation of the sympatho-inhibitory cardiodepressor reflex (Bezold-Jarisch reflex), which is a physiologic response to a critical reduction in intravascular volume and cardiac filling, is the cause of sudden intradialytic hypotension.

Life-span attachment: relations between attachment and socioemotional functioning in adult women.

Relations between the quality of adult women's attachments, their well-being, and their strategies for coping with stress were explored. In Study 1, we examined elderly women's (65-87 years of age) attachments to their adult children. No main effect differences were found, but extreme score analyses revealed that women with insecure attachments more often evidenced relatively extreme negative scores on measures of social, psychological, and physical well-being and reported using more strategies in coping with stress. In Study 2, we examined the quality of attachments of young adult (mean age = 20 years) and mature women (mean age = 38 years), respectively, to their closest attachment figure. Again, few main effects were found but extreme score analyses revealed that insecurely attached women more often scored in the clinical range on depression and reported more responses in coping with stress. Further friends independently reported more anxiety among insecurely attached women.