Continuous positive airways pressure for obstructive sleep apnoea

BACKGROUND

Obstructive sleep apnoea is the periodic reduction (hypopnoea) or cessation (apnoea) of breathing due to narrowing or occlusion of the upper airway during sleep. The main symptom is daytime sleepiness although there it has been linked to premature death, hypertension, ischaemic heart disease, stroke and road traffic accidents.

OBJECTIVES

The main treatment for sleep apnoea is with continuous positive airways pressure (CPAP) treatment, which consists of a flow generator and mask. These are used at night to prevent apnoea, hypoxia and sleep disturbance. The objective was to assess the effects of CPAP in the treatment of obstructive sleep apnoea in adults.

SEARCH STRATEGY

We searched the Cochrane Airways Group RCT register (MEDLINE 1966 to 2000, Embase 1974 to 2000, Cinahl 1982 to 2000) and the reference lists of articles. We consulted experts in the field.

SELECTION CRITERIA

Randomised trials comparing nocturnal CPAP with placebo or other treatments in adults with obstructive sleep apnoea and an apnoea/hypopnoea index greater than five per hour.

DATA COLLECTION AND ANALYSIS

Trial quality was assessed and two reviewers extracted data independently. Study authors were contacted for missing information.

MAIN RESULTS

Twelve trials involving 475 people were included. Most studies had methodological shortcomings. Most trials were of crossover design. Compared with placebo, CPAP showed significant improvements in objective and subjective sleepiness and several quality of life and depression measures. Patients preferred CPAP to placebo (odds ratio 0.4, 95% confidence interval 0.2 to 0.8). There was no significant effect on daytime blood pressure. Compared with oral appliances, CPAP significantly improved the apnoea/hypopnoea index (weighted mean difference -7.3, 95% confidence interval -10.0 to -4.7) and minimum oxygen saturation during sleep. Patients strongly preferred the oral appliance to CPAP (odds ratio 9.5, 95% confidence interval 4.3 to 21.1).

REVIEWER'S CONCLUSIONS

CPAP is more effective than placebo in improving sleepiness and quality of life measures for people with obstructive sleep apnoea. It is more effective than oral appliances in improving respiratory disturbances. Although patients prefer CPAP to placebo, they preference oral appliances to CPAP.

Exposure to increased pressure or hyperbaric oxygen suppresses interferon-gamma secretion in whole blood cultures of healthy humans

This study examines the effects of hyperoxia, increased atmospheric pressure, and hyperbaric oxygen on cytokine synthesis. Five healthy volunteers were exposed to 90 min of room air, 100% oxygen, 10.5% oxygen at 2 atm abs, or 100% oxygen at 2 atm abs (HBO2). All subjects were blinded and randomly exposed to each of the 4 conditions. Immediately before entering the chamber, immediately after exposure, and 3 and 24 h later, blood was drawn and stimulated ex vivo with phorbol myristate acetate (PMA) and phytohemagglutinin A (PHA). Since lymphocytes are the primary source of PMA/PHA-induced interferon-gamma (IFN-gamma), these results were expressed as IFN-gamma production per 10(6) lymphocytes. Following the HBO2 exposure, PMA/PHA-stimulated lymphocytes released 51% less IFN-gamma than cells obtained before the exposure. This suppression persisted for 24 h following HBO2 (P < 0.05). Surprisingly, increased atmospheric pressure alone also inhibited IFN-gamma secretion (P < 0.05). Room air and hyperoxia alone had no significant effect upon IFN-gamma release. HBO2's anti-inflammatory effect may, in part, be due to inhibition of IFN-gamma release.

The Otto E. Aufranc Award: The role of labral lesions to development of early degenerative hip disease

The current authors examined the hypothesis that labral lesions contribute to early degenerative hip disease. Between 1993 and 1999, 436 consecutive hip arthroscopies were done by the senior author. In addition, 54 acetabula were harvested from human adult cadavers. Two hundred forty-one of the 436 (55.3%) patients who had arthroscopies had a 261 labral tears, all located at the articular, not capsular margin of the labrum. Stereomicroscopic examination of the 54 acetabula from cadavers revealed 52 labral lesions. Overall, there was no significant difference between the arthroscopic and cadaveric populations in terms of the incidence of labral tears. (Overall, 73% of patients with fraying or a tear of the labrum had chondral change. Arthroscopic and anatomic observations support the concept that labral disruption and degenerative joint disease are frequently part of a continuum of joint disease.

Empowerment: a view of two low-income African-Americans communities

Field theory and empowerment were used as guiding conceptual frameworks to address empowerment issues in two low-income inner city African-Americans communities. Field theory and empowerment provided a conceptualization of these communities in terms of the possible impact of the physical environment of these communities on their residents and the health care professionals who worked with these residents. The most likely response is learned helplessness and depression that are antithetical to empowerment. These frameworks also were helpful in generating strategies to foster empowerment among these community residents. These strategies include helping residents to redefine their behavior as ways of coping with a hostile environment that confronts them with poverty and racism and to reconnect with natural supports in the community for the purpose of enhancing community coalitions and alliances.

The watershed labral lesion: its relationship to early arthritis of the hip

This study examined the hypothesis that labral lesions contribute to early degenerative hip disease. Between 1993 and 1999, 436 consecutive hip arthroscopies were performed by the senior author (J.C.M.). In addition, 54 acetabula were harvested from human adult cadavers and 10 hips underwent microangiography to determine labral blood supply. Of the 436 arthroscopic patients, 241 (55.3%) had a total of 261 labral tears, all located at the articular, not capsular, margin of the labrum. Stereomicroscopic examination of the 54 cadaver acetabula revealed a total of 52 labral lesions. Overall, there was no significant difference between the arthroscopic and cadaver populations in terms of the incidence of labral tears (P=.315). There was a high association between labral lesions and adjacent acetabular chondral damage. Arthroscopic and anatomic observations support the concept that labral disruption and degenerative joint disease frequently are part of a continuum of joint pathology.

Experimental infection of European red foxes (Vulpes vulpes) with canine herpesvirus

We report on the pathogenicity of canine herpesvirus (CHV) for European red foxes. In the first experiment, we inoculated 10 adult foxes intravenously with a canine isolate of CHV. All foxes became infected and shed CHV in saliva and genital secretions for up to 14 days post-inoculation (p.i.) as evaluated by PCR and/or by virus isolation. All foxes developed clinical signs such as fever, lethargy and evidence of respiratory tract disease. Two foxes died on day 6 p.i., one on day 7 p.i., and one fox was euthanased on day 6 p.i. Tissues taken from the four dead foxes were positive for CHV by PCR. The remaining six foxes recovered after approximately 14 days p.i. Virus particles with morphology typical of herpesviruses were found by electron microscopy in the liver of an infected animal. All surviving foxes developed serum anti-CHV antibodies. In a second experiment, six foxes were dosed perorally with CHV and paired with six untreated controls. Neither the perorally dosed nor the in-contact control foxes developed clinical signs of disease. Infectious CHV was not isolated from any of the dosed or the in-contact foxes but all perorally-infected foxes and one of the in-contact foxes tested PCR-positive for CHV on several occasions p.i. All perorally-infected foxes, but none of the in-contact foxes, seroconverted. In summary, intravenous CHV inoculation caused a clinical disease in adult foxes much more severe than observed in experimentally-infected adult dogs. No clinical disease or virus spread was observed after peroral dosing although viral infection occurred as evidenced by seroconversion.

Head lice infestation: bug busting vs. traditional treatment

The two main methods of managing head lice infestation in the UK are head lice lotions and bug busting; there is no conclusive evidence as to which of these methods is most effective. The aim of this study was to compare the effectiveness of the bug busting method with lotion. A pilot study in the form of a randomized controlled trial involving two semi-rural general practices was used. Thirty children aged 4-16 years were randomly assigned to two intervention groups. After initial dry combing to detect the presence of head lice, one group was treated with phenothrin lotion. The bug busting group received combing using special combs provided in the bug busting pack and hair conditioner. The main outcome measure was the number of adult live lice and nymphs at day 14. On day 14 in the bug busting group, total eradication of head lice had occurred in eight children; in the lotion group, total eradication had occurred in two children (P=0.052); number needed to treat 2.5 (95% CI: 2.19-2.81). These results suggest that bug busting performed by nurses in a controlled situation is an effective method of managing head lice infestation.

Randomized controlled trial of home-based exercise training to evaluate cardiac functional gains

There is evidence that multiple benefits can be obtained through exercise training that leads to increases in peak oxygen consumption (V(O(2))). It is unclear whether significant improvements can also be achieved through unsupervised low-budget home-based training regimes, especially in terms of cardiac functional gains. A randomized cross-over trial was conducted to investigate the effects of a home-based unsupervised exercise training programme of moderate intensity on aerobic capacity, cardiac reserve and peak cardiac power output in healthy middle-aged volunteers. Nine subjects with no known cardiovascular diseases performed symptom-limited treadmill cardiopulmonary exercise tests after an 8-week period of exercise training, and results were compared with those obtained after a similar 'non-exercising' control period. Cardiac output was measured non-invasively during exercise tests using the CO(2)-rebreathing method. With exercise training, resting heart rate decreased significantly from 88.3+/-3.4 to 78.7+/-3.2 beats.min(-1) (P<0.05), heart rate at a submaximal workload (V(O(2))=1.5 litres.min(-1)) decreased from 125.5+/-2.4 to 115.5+/-1.6 beats.min(-1), and peak V(O(2)) increased by 9% from 2.62+/-0.19 to 2.85+/-0.18 litres.min(-1) (P<0.01). Baseline cardiac power output was 1.11+/-0.05 W, and this remained unchanged with training. Peak cardiac power output increased by 16% from 4.1+/-0.3 to 4.7+/-0.3 W (P<0.001), and cardiac reserve increased by 21% (P<0.01). A major contribution to these increases was from the 11% increase in stroke volume, from 100.1+/-5.3 to 111.2+/-6.2 ml (P<0.001). All subjects reported more positive perceptions of their health (P<0.05), fitness (P<0.01) and levels of activity (P<0.01) after the training period. These results show that motivated subjects undergoing low-budget unsupervised home-based exercise training of moderate intensity can derive benefit in terms of symptoms, aerobic capacity and cardiac functional reserve.

Systematic review of clinical effectiveness of pressurised metered dose inhalers versus other hand held inhaler devices for delivering corticosteroids in asthma

OBJECTIVE

To determine the clinical effectiveness of pressurised metered dose inhalers (with or without spacer) compared with other hand held inhaler devices for the delivery of corticosteroids in stable asthma.

DESIGN

Systematic review of randomised controlled trials.

DATA SOURCES

Cochrane Airways Group trials database (Medline, Embase, Cochrane controlled clinical trials register, and hand searching of 18 relevant journals), pharmaceutical companies, and bibliographies of included trials.

TRIALS

All trials in children or adults with stable asthma that compared a pressurised metered dose inhaler with any other hand held inhaler device delivering the same inhaled corticosteroid.

RESULTS

24 randomised controlled trials were included. Significant differences were found for forced expiratory volume in one second, morning peak expiratory flow rate, and use of drugs for additional relief with dry powder inhalers. However, either these were within clinically equivalent limits or the differences were not apparent once baseline characteristics had been taken into account. No significant differences were found between pressurised metered dose inhalers and any other hand held inhaler device for the following outcomes: lung function, symptoms, bronchial hyper-reactivity, systemic bioavailability, and use of additional relief bronchodilators.

CONCLUSIONS

No evidence was found that alternative inhaler devices (dry powder inhalers, breath actuated pressurised metered dose inhalers, or hydrofluoroalkane pressurised metered dose inhalers) are more effective than the pressurised metered dose inhalers for delivery of inhaled corticosteroids. Pressurised metered dose inhalers remain the most cost effective first line delivery devices.

Systematic review of clinical effectiveness of pressurised metered dose inhalers versus other hand held inhaler devices for delivering beta (2 )agonists bronchodilators in asthma

OBJECTIVES

To determine the clinical effectiveness of pressurised metered dose inhalers compared with other hand held inhaler devices for delivering short acting beta(2) agonists in stable asthma.

DESIGN

Systematic review of randomised controlled trials.

DATA SOURCES

Cochrane Airways Group specialised trials database (which includes hand searching of 20 relevant journals), Medline, Embase, Cochrane controlled clinical trials register, pharmaceutical companies, and bibliographies of included trials.

TRIALS

All trials in children or adults with stable asthma that compared the pressurised metered dose inhaler (with or without a spacer device) against any other hand held inhaler device containing the same beta(2) agonist.

RESULTS

84 randomised controlled trials were included. No differences were found between the pressurised metered dose inhaler and any other hand held inhaler device for lung function, blood pressure, symptoms, bronchial hyperreactivity, systemic bioavailability, inhaled steroid requirement, serum potassium concentration, and use of additional relief bronchodilators. In adults, pulse rate was lower in those using the pressurised metered dose inhaler compared with those using Turbohaler (standardised mean difference 0.44, 95% confidence interval 0.05 to 0.84); patients preferred the pressurised metered dose inhaler to the Rotahaler (relative risk 0.53, 95% confidence interval 0.36 to 0.78); hydrofluoroalkane pressurised metered dose inhalers reduced the requirement for rescue short course oral steroids (relative risk 0.67, 0.49 to 0.91).

CONCLUSIONS

No evidence was found to show that alternative inhaler devices are more effective than standard pressurised metered dose inhalers for delivering acting beta(2 )agonist bronchodilators in asthma. Pressurised metered dose inhalers remain the most cost effective delivery devices.

Antral motility measurements by magnetic resonance imaging

Magnetic resonance imaging has been recently proposed as a promising, noninvasive technique to assess the motility of the gastric antrum. However, so far the reproducibility and dependence on test meal composition has not been evaluated. In this study, snapshot echo-planar magnetic resonance imaging was used to measure the frequency, propagation speed and percentage occlusion of antral contractions in 28 healthy volunteers. They were fed either liquid (n=12), mixed liquid/solid (n=8) or mixed viscous/solid (n=8) nutrient (1350 kJ) test meals, and a total of 208 motility measurements were performed. No effect of meal type on antral motility parameters was observed. Antral contraction frequency was 3.0 +/- 0.2 min(-1) (mean +/- SD, n=164), propagation speed was 1.6 +/- 0.2 mm s(-1) (n=164) and the percentage occlusion was 58 +/- 14% (n=76). Overall, 21% of measurements did not provide useful antral motility data, because, in the supine position, the antrum was not filled by the test meal. Simple methods to overcome this and reduce scanning time to a minimum are proposed. The results show that the noninvasive magnetic resonance imaging evaluation of antral motility is accurate and reproducible and has potential to become a standard tool for such investigations.

Diagnosis of culture-negative female genital tract tuberculosis with peritoneal involvement by polymerase chain reaction

BACKGROUND

Female genital tract tuberculosis (TB) is a common cause of infertility in developing countries. It is a paucibacillary form of the disease of which smears and cultures are usually negative.

CASE

We were able to use polymerase chain reaction (PCR) amplification of Mycobacterium tuberculosis DNA to support a clinical and histologic diagnosis of a typical case of culture negative female genital tract TB.

CONCLUSION

PCR may be a useful adjunct to diagnostic efforts in gynecologic tuberculosis.

Comparison of cross-sectional renal function measurements in African Americans with hypertensive nephrosclerosis and of primary formulas to estimate glomerular filtration rate

Renal function measurements were obtained in 1,703 African Americans with presumed hypertensive nephrosclerosis who were screened for entry into the African-American Study of Hypertension and Kidney Disease (AASK). We examined the effect of race on relationships involving renal variables by comparing African Americans enrolled into the AASK with non-African Americans enrolled into the Modification of Diet in Renal Disease (MDRD) study. We examined the effect of gender on renal variables by comparing African American men and women. We compared various methods for estimating glomerular filtration rate (GFR) with iodine 125-labeled ((125)I)-iothalamate GFR. AASK data were also used to derive a new formula for estimating GFR in African Americans. After adjusting for age, sex, and baseline GFR, African American patients on the AASK study were heavier and had larger body surface areas and body mass indices than either MDRD African Americans or non-African Americans. African Americans had greater serum creatinine levels and urinary creatinine excretions for any given level of GFR. Mean GFR was greater in African American men than African American women (59.7 versus 51.7 mL/min/1.73 m(2)), although serum creatinine levels were also greater in men (1.91 versus 1.73 mg/dL). Seventy-eight percent of women with serum creatinine levels between 1.2 and 1.5 mg/dL had GFRs less than 65 mL/min/1.73 m(2). For African Americans in the AASK, GFR was overestimated by the 24-hour creatinine clearance and underestimated by the Cockcroft-Gault formula. A prediction formula developed in the MDRD study more accurately predicted GFR in AASK patients than these measurements. AASK data were also used to derive a new five-term formula for estimating GFR that was slightly more accurate in the African Americans in the AASK than the MDRD formula (median percentage of error, 12.4% for the MDRD formula versus 12.1% for the AASK formula). Important differences exist in renal variables between African Americans and non-African Americans and between African American men and African American women. Formulas using demographic data and readily measured serum values estimate (125)I-iothalamate GFR.

Involving patients in research: setting up a service users' advisory group

Looks at some of the issues raised by patients' involvment in the research process. Uses the example of a service users' advisory group established as part of a diabetes service evaluation in the north of England. Key conclusions were: a precise role for the group should be specified at the outset; genuine user involvement is needed; wide and accurate representation of all relevant groups in society is essential; and, researchers must approach users with open minds with a view to shared decision making rather than control.

Do all patients in primary care who may benefit from eradication of Helicobacter pylori have access to effective care?

The purpose of this study was to identify those patients who would benefit from eradication therapy for Helicobacter pylori and to understand the scale of service changes needed to implement eradication therapy. All general practices in Bradford Health Authority were invited to take part in the study. Patients who had received more than one repeat prescription for proton pump inhibitors or H(2) receptor antagonists in the previous twelve months were identified using the repeat prescription systems in the participating practices. Their case notes were examined and the relevant data items extracted by a trained project worker. Forty-four out of 100 practices agreed to take part and they accounted for a population of 262 647 people. Of that population, 2.3% (6037) of patients were on long-term acid suppressing treatment. Seventy-nine percent (n=4784) of patients on long-term acid suppression had a diagnosis recorded in the records; 17% (n=1028) had duodenal ulcer; 5% (n=278) gastric ulcer and the rest, 58% (n=3478), consisted of patients labelled as dyspepsia, heartburn, gastritis, and non-ulcer dyspepsia. Only 131 (10%) of those patients with peptic ulcer had been prescribed eradication therapy. Endoscopy and barium meal examinations had been used to confirm the diagnosis in 2715 patients. In the remaining patients there was no information in the case notes to suggest whether the diagnosis had been confirmed by investigations.A substantial proportion of patients previously diagnosed as having peptic ulcer have not been offered eradication therapy demonstrating a delay in getting research evidence into practice. To ensure all patients within a health district who may benefit from eradication therapy, do benefit, a systematic approach including access to additional investigative facilities is required.

A phase I and pharmacologic study of 9-aminocamptothecin administered as a 120-h infusion weekly to adult cancer patients

PURPOSE

To define the toxicity profile and the recommended phase II doses of 9-aminocamptothecin (9-AC) administered as a weekly 120-h infusion.

METHODS

9-AC was administered over 120 h weekly to 55 adult cancer patients with solid tumors over doses ranging from 0.41 to 0.77 mg/m2 per day in a phase I and pharmacologic study. 9-AC formulated in dimethylacetamide/polyethylene glycol (DMA) was administered on a 3 of 4-week schedule, and the newer colloidal dispersion (CD) formulation was given on a 2 of 3-week schedule.

RESULTS

Overall, 193 courses of therapy were administered over 122 dose levels. On the 3 of 4-week schedule, 9-AC DMA infused at > or = 0.6 mg/m2 per day for 120 h weekly produced dose-limiting neutropenia, thrombocytopenia, and diarrhea, or resulted in 1-2-week treatment delays. Shortening treatments to 2 of 3 weeks resulted in dose-limiting neutropenia and fatigue at infusion rates > 0.72 mg/m2 per day. The ratio of 9-AC lactone to total (carboxylate + lactone) drug plasma concentrations at steady-state was 0.15 +/- 0.07. Clinical toxicities and drug pharmacokinetics were not substantially different between the DMA and CD formulations. One objective response was observed in a patient with bladder cancer and minor responses were observed in patients with lung and colon cancers. Plasma area under the concentration versus time curve for 9-AC lactone modestly correlated with the degree of thrombocytopenia (r=0.51) using a sigmoid Emax pharmacodynamic model.

CONCLUSION

The recommended phase II dose for the 9-AC DMA formulation is 0.48 mg/m2 per h over 120 h for 3 of 4 weeks and for the 9-AC CD formulation is 0.6 mg/m2 per day over 120 h for 2 of 3 weeks. Both regimens were well tolerated and feasible to administer.

Fluoride-releasing elastomeric modules reduce decalcification: a randomized controlled trial

OBJECTIVE

To determine whether fluoride releasing elastomeric modules reduced the incidence of decalcification around orthodontic brackets during a complete course of orthodontic treatment.

DESIGN

A randomised controlled, split mouth design.

SETTING

The study was carried out in the orthodontic department of Newcastle-upon-Tyne Dental Hospital, UK.

SUBJECT AND METHODS

21 consecutive patients (126 teeth) undergoing fixed appliance therapy were studied. A split mouth technique was adopted to examine the upper labial segment, where one side (left or right) was randomly assigned to the experimental group, and the opposite side served as a control throughout their course of orthodontic treatment.

INTERVENTIONS

The control teeth were ligated to the archwire using conventional modules. The experimental teeth were ligated to the archwire using Fluoride releasing elastomeric modules.

OUTCOME MEASURES

Standardised photographs were taken of the upper labial segment before and after completion of orthodontic treatment, and the degree of decalcification assessed in each tooth quadrant, using a modification of the Enamel Defect Score.

RESULTS

Decalcification was found to occur in both treatment groups, though to a significantly greater degree on the control side (p = 0.002). The fluoride module side showed significantly fewer serious decalcified lesions than the control (p = 0.013). No patients withdrew from the study.

CONCLUSIONS

It would appear that the use of fluoride releasing elastomeric modules reduces the degree of decalcification experienced during orthodontic treatment.

Vitamin E correlates inversely with non-transferrin-bound iron in sickle cell disease

Decreased serum vitamin E levels are found in homozygous sickle cell disease (SCD). Excessive transfusions may lead high non-transferrin-bound iron (NTBI). Hypothesizing a relationship between the two, vitamin E (measured using high performance liquid chromatography) was significantly lower in 30 SCD patients than in 30 age-/sex-matched controls (P < 0.001), but NTBI (bleomycin assay) was higher (P < 0.001). Vitamin E was lower in 10 transfused patients than in 20 non-transfused patients (P < 0.001) with a significant inverse correlation between the NTBI and vitamin E (r = -0.58, P < 0.001). NTBI associated with iron overload in SCD may increase the potential for oxidative damage and low vitamin E activity may compound this effect.

Are specialist outreach clinics for orthodontic consultation effective? A randomised controlled trial

OBJECTIVE

To develop outreach clinics for orthodontic consultation and evaluate their costs and effectiveness.

DESIGN

Single centre randomised controlled trial with random allocation of referred patients to outreach or main base consultation appointments.

SETTING

One hospital orthodontic department and three community health centre clinics in Greater Manchester. Subjects 324 patients who were referred for orthodontic treatment.

MAIN OUTCOME MEASURES

The outcome of consultation, the cost and duration of the visit and the consumer's perceptions of the visit.

RESULTS

There were no differences in outcome of the consultation. While consumer travel costs and the duration of appointments were significantly higher for the main base clinics, these differences were not great. However, consumers preferred to attend an appointment in an outreach clinic.

CONCLUSIONS

There do not appear to be marked advantages or disadvantages in providing consultation appointments for orthodontics in outreach clinics