The effect of a very low-calorie diet-induced weight loss on the severity of obstructive sleep apnoea and autonomic nervous function in obese patients with obstructive sleep apnoea syndrome.

The aim of this study was to examine the effect of a very low-calorie diet (VLCD)-induced weight loss on the severity of obstructive sleep apnoea (OSA), blood pressure and cardiac autonomic regulation in obese patients with obstructive sleep apnoea syndrome (OSAS). A total of 15 overweight patients (14 men and one woman, body weight 114 +/- 20 kg, age 52 +/- 9 years, range 39-67 years) with OSAS were studied prospectively. They were advised to follow a 2.51-3.35 MJ (600-800 kcal) diet daily for a 3-month period. In the beginning of the study, the patients underwent nocturnal sleep studies, autonomic function tests and 24-h electrocardiograph (ECG) recording. In addition, 15 age-matched, normal-weight subjects were studied. They underwent the Valsalva test, the deep-breathing test and assessment of heart rate variability at rest. The sleep studies and autonomic function tests were repeated after the weight loss period. There was a significant reduction in weight (114 +/- 20 kg to 105 +/- 21 kg, P < 0.001), the weight loss being 9.2 +/- 4.0 kg (range 2.3-19.5 kg). This was associated with a significant improvement in the oxygen desaturation index (ODI4) during sleep (31 +/- 20-19 +/- 18, P < 0.001). Before the weight loss the OSAS patients had significantly higher blood pressure (150 +/- 18 vs. 134 +/- 20, P < 0.05, for systolic blood pressure, 98 +/- 10 vs. 85 +/- 13, P < 0.05, for diastolic blood pressure) and heart rate (67 +/- 10 beats min-1 vs. 60 +/- 13, P < 0.05) at rest than the control group. They had also lower baroreflex sensitivity (4.7 +/- 2.8 ms mmHg-1 vs. 10.8 +/- 7.1 ms mmHg-1, P < 0.01). During the weight reduction, the blood pressure declined significantly, and the baroreflex sensitivity increased by 49%. In conclusion, our experience shows that weight loss with VLCD is an effective treatment for OSAS. Weight loss improved significantly sleep apnoea and had favourable effects on blood pressure and baroreflex sensitivity that may have prognostic implications.

Cardiac sympathovagal balance during sleep apnea episodes.

The main acute cardiovascular effects of obstructive sleep apnea syndrome (OSAS) are elevation of blood pressure and reflectory bradycardia, which are followed by an abrupt tachycardia on resumption of breathing. This haemodynamic instability is related to hypoxemia and arousal, and may lead to increased risk from cardiac arrhythmias and sudden cardiac death, as well as to the development of chronic arterial hypertension, in these patients. The aim of this study was to apply frequency domain analysis of heart rate variability (HRV) measured from continuous electrocardiogram (ECG) recordings to evaluate how cardiac autonomic function, and especially cardiac sympathovagal tone, changes during sleep apnea episodes. We identified 41 apneas leading to more than 4%-unit arterial oxygen desaturation in 12 patients (11 men, 1 woman (correction for women), age range 27-67 years). Frequency domain analysis of HRV was performed from ECG recordings using 4 min epochs starting 20 min before apnea began and lasting 20 min after the beginning of apnea. The mean (+/-SEM) fall in oxygen saturation during the apnea was 6.8 +/- 0.6%-units. While high frequency band (HF, reflects cardiac vagal activity) remained unchanged, low frequency band (LF, mainly sympathetic activity) showed a constant increase, leading to significant change in the sympathovagal balance (LF/HF ratio). In conclusion, concordantly with previous peripheral sympathetic-nerve recordings, frequency domain analysis of HRV is able to detect sympathetic activation during sleep apnea episodes, leading to marked change in the sympathovagal balance.

The contralateral ear in patients with chronic otitis media.

The status and hearing function of the contralateral ears in 493 patients undergoing surgery for chronic otitis media were studied at the final follow-up examination of the patients (on average, 6.5 years after the surgical treatment). In only 37% of the patients was the contralateral ear found to be normal, with atrophy of the pars tensa and tympanosclerosis being the most common abnormal findings, followed by pars tensa and attic retractions. In 18% of the patients, the contralateral ear had also undergone surgery. In only 64% of the patients, the contralateral ears had normal (< or = 20 dB) hearing levels, and in 21%, the hearing levels were > 30 dB, the hearing function of patients with cholesteatoma being worse than that of other patients with chronic otitis media. In 14 (3%) of the patients, even the better hearing ear had a hearing level of > 60 dB, including one patient with both ears totally deaf. To improve the functional outcome of patients with chronic otitis media, earlier and more effective treatment of middle ear infections is needed.

Propofol-nitrous oxide versus thiopentone-isoflurane-nitrous oxide anaesthesia for uvulopalatopharyngoplasty in patients with sleep apnea.

A randomized prospective study was performed to compare the recovery in 41 patients undergoing uvulopalatopharyngoplasty (UPPP) with either propofol-nitrous oxide-fentanyl or thiopentone-isoflurane-nitrous oxide-fentanyl anaesthesia. The patients were referred to UPPP after examination including polysomnography and otorhinolaryngological examination. The propofol group received propofol 2 mg.kg-1 for induction followed by an infusion of 10 mg.kg-1.h-1 after intubation. The thiopentone-isoflurane group received 5 mg.kg-1 of thiopentone for induction followed by isoflurane (0.5-2%) after intubation. Other medication was similar in both groups. In the propofol group the patients had a significantly better oxygen saturation during the first postoperative hour (P < 0.05), and a higher rate of breathing (P < 0.05), indicating a more rapid recovery of the physiologic control of breathing. Pain as measured by visual analogue score was lower (P < 0.05) during the second postoperative hour compared with the isoflurane group. Apneic episodes occurred with similar frequency in both groups, and they were related to the severity of obstructive sleep apnea (OSA). We conclude that propofol is preferable to thiopentone-isoflurane in UPPP operations, because physiologic respiratory control recovers faster and postoperative pain is less intense.

Tympanomastoidectomy for chronic otitis media without cholesteatoma.

A series of 221 ears with chronic suppurative otitis media without cholesteatoma is presented--84% of the cases were treated using one-stage tympanomastoidectomy and 15% underwent cortical mastoidectomy with planned second-stage tympanoplasty. Mean follow-up period was 6.3 years. Control of infection succeeded in 92% after the primary operation. Failures were most common in ears infected with Pseudomonas aeruginosa. Postoperative cholesteatoma developed in 5 ears (2.2%). Hearing results were unsatisfactory; a postoperative air-bone gap within 20 dB was achieved in only 62%. In revision operations, retained mastoid air cells were found in 64% of ears with recurrent or persistent discharge. Thirty-seven percent of patients with unsuccessful outcome were observed to have a possible underlying or concomitant disease. The importance of intensive preoperative conservative treatment and careful surgical technique is stressed.

View from beneath: pathology in focus bilateral acinic cell tumours of the parotid gland.

A 55-year-old woman was operated because of bilateral parotid tumours which appeared with an interval of three years. Histopathologically, both of the tumours had characteristics typical of acinic cell tumour, so-called clear cell type. Both tumours were regarded to be multifocal. In the case of bilateral parotid tumours, acinic cell tumour should also be kept in mind and total parotidectomy is the treatment of choice.

A multi-centre evaluation of the FP-900 analyzing system.

The performance of the FP-900 Analyzing system manufactured by Labsystems Oy, Helsinki, Finland, was evaluated in a multi-centre study according to the principle outlined in the 1st Draft of the Standard for Instrument Testing produced by the European Committee for Clinical Laboratory Standards (ECCLS). The FP-900 System comprises a photometer for simultaneous measurement of the absorbance in a nine-compartment cuvette block, and the accessories for handling samples (sampler, simultaneous dispensing of 9 reagent charges, incubator with thermostat and shaker, and centrifuge); the photometer function, printout of results and data processing are programmable with a microprocessor. The performance specifications given by the manufacturer were checked when appropriate. As examples of typical methodologies cholesterol was selected as an end-point absorbance method, creatinine as a fixed-time (two-point) kinetic and aspartate aminotransferase as multi-point, continuous method. The within- and between-laboratory imprecision, deviation from assigned values of commercial control sera, and carry-over were determined. The performance was compared with other analytical systems: Mark I Autoanalyzer and Hitachi 705. The cost, speed and capacity was estimated from the results of the present study. The performance of the analyser and results of applying the ECCLS Draft to actual instrument testing are discussed.