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Biomedical subjects

R Jokic

Publications and source records attributed to R Jokic.

9 recordsLinked to original sources
PubMed1999

Effect of high versus low ambient humidity on the severity of obstructive sleep apnoea.

BACKGROUND: Surface tension forces appear to make a significant contribution to upper airway closure in patients with obstructive sleep apnoea (OSA). It is possible that drying of the upper airway mucosa at night might contribute to these surface tension forces and the severity of OSA might therefore change with alteration of the ambient humidity. METHODS: A randomised single blind crossover study of high ambient relative humidity (HRH) versus low ambient relative humidity (LRH) was performed in 12 men of mean (SD) age 49 (9) years with mild OSA (apnoea/hypopnoea index (AHI) 14 (5.2)). On one night patients slept in continuous HRH (85 (4)%, range 80-93%) and on the other in LRH (16 (4)%, range 11-22%). RESULTS: The AHI was similar on the HRH and LRH nights (mean difference 3; 95% CI -2 to 9, p = 0.20 and no statistically significant differences in AHI were observed on the two nights after standardising for body position and sleep stage. Sleep stage distribution and the proportion of time spent in the supine position were similar on the HRH and LRH nights. The number of non-respiratory arousals was also similar on the two nights. CONCLUSION: Altering ambient humidity alone has no significant impact on the severity of OSA.

Humans↗
PubMed1999

Positional treatment vs continuous positive airway pressure in patients with positional obstructive sleep apnea syndrome.

OBJECTIVES: The aim of this study was to compare the relative efficacy of continuous positive airway pressure (CPAP) and positional treatment in the management of positional obstructive sleep apnea (OSA), using objective outcome measures. DESIGN: A prospective, randomized, single blind crossover comparison of CPAP and positional treatment for 2 weeks each. SETTING: A university teaching hospital. PATIENTS: Thirteen patients with positional OSA, aged (mean+/-SD) 51+/-9 years, with an apnea-hypopnea index (AHI) of 17+/-8. MEASUREMENTS: (1) Daily Epworth Sleepiness Scale scores; (2) overnight polysomnography, an objective assessment of sleep quality and AHI; (3) maintenance of wakefulness testing; (4) psychometric test battery; (5) mood scales; (6) quality-of-life questionnaires; and (7) individual patient's treatment preference. RESULTS: Positional treatment was highly effective in reducing time spent supine (median, 0; range, 0 to 32 min). The AHI was lower (mean difference, 6.1; 95% confidence interval [CI], 2 to 10.2; p = 0.007), and the minimum oxygen saturation was higher (4%; 95% CI, 1% to 8%; p = 0.02) on CPAP as compared with positional treatment. There was no significant difference, however, in sleep architecture, Epworth Sleepiness Scale scores, maintenance of wakefulness testing sleep latency, psychometric test performance, mood scales, or quality-of-life measures. CONCLUSION: Positional treatment and CPAP have similar efficacy in the treatment of patients with positional OSA.

Cross-Over Studies↗
PubMed1998

Surface tension forces in sleep apnea: the role of a soft tissue lubricant: a randomized double-blind, placebo-controlled trial.

Upper airway obstruction in patients with sleep apnea may occur in the absence of a negative intraluminal upper airway pressure. We hypothesized that surface tension forces may play a role in the pathogenesis of obstructive sleep apnea (OSA), and that a topical soft tissue lubricant might reduce the severity of OSA. Ten male patients (age 49 +/- 10 yr [mean +/- SD]; body mass index [BMI] 31 +/- 5 kg/m2) with OSA (apnea-hypopnea index [AHI] 17 +/- 9) were studied. The arousal index was lower with the lubricant treatment than with placebo (mean difference 8; 95% CI 4 to 11 arousals/h; p = 0.001). The AHI was lower, in each of the 10 patients, on the lubricant treatment than the placebo (mean change 10, 95% CI 6 to 13; p = 0.0003). The lower AHI with lubricant as compared with placebo was present in both supine (mean difference 13; 95% CI 5 to 20; p = 0.006) and nonsupine (mean difference 6; 95% CI 0 to 12; p = 0.05) positions. There was no significant difference in sleep architecture between the lubricant and placebo treatments. Application of a topical lubricant consistently reduced the severity of OSA. This implies a pathogenetic role for surface tension forces in OSA, and a potential role for surface tension-reducing agents in the treatment of OSA.

Bronchi↗
PubMed1998

Continuous positive airway pressure requirement during the first month of treatment in patients with severe obstructive sleep apnea.

OBJECTIVES: (1) To compare the continuous positive airway pressure (CPAP) requirement at the time of diagnosis (T0), after 2 weeks (T2), and after 4 weeks (T4) of CPAP treatment, in patients with severe obstructive sleep apnea (OSA); and (2) to assess whether any alteration in CPAP requirement over the first 4 weeks of CPAP treatment would influence daytime alertness, subjective sleepiness, or mood. DESIGN: A prospective, controlled, single-blind crossover study. SETTING: University teaching hospital. PATIENTS: Ten patients with newly diagnosed and previously untreated severe OSA (aged 52+/-9 years, apnea hypopnea index [AHI] of 99+/-31) and subsequently 10 control patients (aged 52+/-11 years, AHI 85+/-17). MEASUREMENTS: Overnight polysomnography with CPAP titration to determine the CPAP requirement, which was standardized for body position and sleep stage, on all three occasions (T0, T2, T4). Objective sleep quality, daytime alertness, subjective sleepiness (Epworth Sleepiness Scale), and mood (Hospital Anxiety and Depression Scale). RESULTS: CPAP requirement decreased from T0 to T2 (median difference, 1.5 cm H2O, 95% confidence interval [CI], 1.1 to 2.7 cm H2O, p=0.0004) and did not differ between T2 and T4. Use of the lower CPAP pressure during T2 to T4 was associated with a decrease in Epworth scale (mean difference, 2.6, 95% CI, 1.2 to 4; p=0.01) and anxiety (median change, 2; 95% CI, 0.5 to 2.9, p=0.03) scores, as compared with the first 2 weeks. Daytime alertness did not differ between T0 to T2 and T2 to T4. CONCLUSION: CPAP requirement falls within 2 weeks of starting CPAP treatment. A change to the lower required CPAP was not associated with any deterioration in daytime alertness but was associated with small subjective improvements in sleepiness and mood.

Cross-Over Studies↗
PubMed1997

The current dilemma with spirometric inclusion criteria for asthma drug trials.

BACKGROUND: Spirometric inclusion criteria for asthma drug studies often require resting airflow obstruction and resting bronchoconstriction. By current standards, these criteria define suboptimal to poor asthma control. OBJECTIVE: To determine what proportion of asthmatic patients attending a tertiary University-based respiratory clinic meet typical drug study spirometric criteria of a baseline FEV1 of 50% to 80% predicted and > or = 15% delta FEV1 improvement following 200 micrograms inhaled albuterol. METHODS: A retrospective review was performed on charts of white caucasian asthmatic patients attending three respiratory physician outpatient clinics at a University-based tertiary referral center. We reviewed charts of all patients with chronic asthma under current therapy. We excluded subjects with additional lung diseases that might affect lung function. Spirometric data were extracted from the most recent scheduled outpatient visit. RESULTS: We reviewed 590 charts of patients with mean age 35.3 +/- 18.3 years (range 6 to 94), 43% male, and 50% atopic. There was objective evidence of variable airflow obstruction or airway hyperresponsiveness in 70.2%; the diagnosis of asthma was based on historical data alone in 29.8%. The majority of patients (87.5%) required inhaled corticosteroids with more than 50% using medium to high doses. Baseline FEV1 was > 80% in 84.6% of subjects, 50% to 80% in 14.4%, and < 50% in 1.0%. FEV1 improved by > or = 15% 10 to 15 minutes after 200 micrograms inhaled albuterol in 13.6%. Only 9.0% of the 590 asthmatic patients fulfilled both criteria (FEV1 50% to 80% and delta FEV1 > or = 15%). CONCLUSION: Less than 10% of asthmatic patients attending a tertiary referral respiratory clinic fulfilled typical spirometry inclusion criteria for asthma drug trials. We suggest this approach to enrollment in asthma drug studies be reevaluated.

Administration, Inhalation↗
PubMed1996

Obstructive lung disease and sleep.

There is a significant interaction between obstructive lung disease and sleep--sleep is associated with clinical deterioration in obstructive lung disease, and vice versa. Knowledge of the pathophysiology of deterioration in obstructive lung disease during sleep is essential to the understanding of the management of this problem. Recent information has helped to clarify this pathophysiology and has led to more aggressive treatment for deterioration of obstructive lung disease during sleep. Whether this newer and more aggressive treatment strategy improves survival or morbidity in these conditions is a challenge for future research.

Asthma↗
PubMedDate not supplied

Protease inhibitor phenotype BsaskatoonM is not associated with emphysema - a 20-year follow-up study.

OBJECTIVE: To investigate the association between the PiBsaskatoon variant of alpha-1 protease inhibitor (a1 Pi), present in the heterozygous state, and the development of emphysema. DESIGN: Twenty-year follow-up in the third generation of a family with the variant, naturally controlled with regard to both environmental influences and other genetic factors. SETTING: University teaching hospital. POPULATION STUDIED: Ten siblings, five with PiBsaskatoonM phenotype and five with PiM phenotype, 33 to 46 years of age. INTERVENTIONS: Respiratory symptoms and smoking histories; pulmonary function tests, including static lung volumes, dynamic lung volumes before and after salbutamol 200 mg, and diffusing capacity; allergen prick skin tests; serum a1 Pi level, chest radiographs and high resolution computerized tomography lung scans MAIN RESULTS: The two groups of siblings had similar mean ages, smoking histories and prevalence of current mild respiratory symptoms. Pulmonary function data showed normal mean values and no statistically significant differences for all the variables between the two groups. Chest radiographs were normal in all subjects. High resolution computerized tomography scans were normal in eight subjects, and demonstrated mild and very mild centrilobular emphysema in the two subjects with greatest smoking histories (approximately 30 pack-year each); both of these were PiBsaskatoonM phenotype. CONCLUSION: There is no evidence of an association between a1 Pi phenotype PiBsaskatoonM and the development of emphysema.

Adult↗