PubMed Health⌕ Search

Biomedical subjects

D Cheung

Publications and source records attributed to D Cheung.

At least 19 recordsLinked to original sources
PubMed2006

Improved lung function and symptom control with formoterol on demand in asthma.

Many asthma patients remain symptomatic despite maintenance therapy with inhaled corticosteroids (ICS) and salbutamol as rescue medication. In the present study the relative efficacy and preference for as-needed formoterol compared with salbutamol was examined. In total, 211 patients with a mean age of 45 yrs (mean forced expiratory volume in one second (FEV1) 77% predicted normal), using ICS, were randomised to 3 weeks' double-blind treatment with as-needed formoterol 4.5 microg Turbuhaler and with as-needed salbutamol 100 mug Turbuhaler in a cross-over fashion. Overall, lung function and symptom control were better with as-needed formoterol than with as-needed salbutamol. During as-needed formoterol treatment daytime and night-time symptom scores were lower, peak expiratory flow and FEV1 were higher and patients experienced fewer disturbed nights (34%) compared with as-needed salbutamol. Patients preferred the formoterol treatment to salbutamol. Of the 162 patients expressing a preference, formoterol was preferred by 68% (95% confidence interval: 60-75). Subjective assessment of effectiveness also favoured formoterol, which was perceived as slightly faster acting than salbutamol. In conclusion, as-needed formoterol improved symptoms and lung function compared with salbutamol and was perceived as more effective and at least as fast acting for symptom relief.

Adult↗
PubMed2005

The consent and counselling of patients for cataract surgery: a prospective audit.

PURPOSE: The aims of ideal preoperative informed consent include educating the patient adequately to enable an autonomous decision to be made without causing undue anxiety. We study how the paternalistic and nonpaternalistic approaches meet this ideal. The influence of the new patient consent forms is also assessed. METHODS: Two cycles of a prospective clinical audit are presented. An assessment of relevant patient knowledge was performed by patient interview. Visual analogue scales were used to quantify patient anxiety. RESULTS: The first cycle, examining a paternalistic approach, demonstrated: 37% of patients understood what a cataract was and 48% understood what surgery involved. 48% misunderstood that cataract surgery was completely risk free. In total, 80% of patients undergoing second eye surgery believed that it was completely risk-free. Average anxiety visual analogue scores (VAS) for cataract surgery were low (2.89). The second cycle, examining the nonpaternalistic approach combined with the implementation of new consent forms showed that, despite more explicit repeated preoperative consent: 39% of patients understood correctly what a cataract was, 28% understood what surgery involved and 43% misunderstood that surgery was completely risk-free. All patients undergoing second eye surgery thought that it was risk-free. The average anxiety VAS for cataract surgery were moderate (5.00). CONCLUSIONS: Both paternalistic and non-paternalistic approaches to informed consent are inadequate in meeting the demands of the ideal informed consent. The new patient consent forms appear to have little effect in influencing patient knowledge about their surgery. Patients undergoing second eye surgery often have an overoptimistic view of cataract surgery.

Aged↗
PubMed2004

Brown deposits in the optic of foldable intraocular lenses in patients with uveitis.

PURPOSE: To report a new finding of brown deposits scattered in the substance of the optic of foldable intraocular lenses (IOL) following phakoemulsification in patients with uveitis. METHODS: Consecutive uveitis patients (54 patients, 71 eyes) who had undergone phakoemulsification with a foldable posterior chamber IOL between March 1996 and November 2000 were studied. A variety of biomaterials from seven different manufacturers had been implanted. One masked observer using slit-lamp biomicroscopy assessed deposits in the substance of the optic of the IOL. RESULTS: Brown deposits were detected in the substance of the optic of 25/71 (35%) IOLs with 18/22 (82%) of AcrySof MA60BM IOLs being affected. Using logistic regression analysis, the AcrySof MA60BM IOL was significantly associated with the presence of deposits (adjusted odds ratio=38.5, 95% CI 6.9-200, P<0.001). Using multiple regression analysis, there was a significant association between the severity of deposits and the use of the AcrySof MA60BM IOL (P=0.005). Compared with other foldable IOLs implanted, the AcrySof MA60BM IOL was 38.5 times more likely to develop intra-IOL deposits. There was no association with those eyes that had undergone increased intraocular manipulations. The deposits did not appear to affect visual acuity. CONCLUSIONS: To our knowledge the finding of brown intra-IOL deposits has not previously been described. These deposits are more frequent in the AcrySof MA60BM implant than the other foldable implants studied. They share some similarities with glistenings, but their exact nature remains unknown.

Adult↗
PubMed2003

Cataract surgery for natural rubber latex allergic patients.

The prevalence of reactions against natural rubber latex (NRL) is thought to be increasing in both the general public and healthcare workers. These can vary from mild benign skin reactions to bronchospasm, anaphylactic shock, and death. Difficulties exist for ophthalmic departments wishing to establish protocols in providing 'latex-free environments' for patients undergoing cataract surgery. Currently no legislation exists regarding the labelling of NRL-containing products in the United Kingdom with information on a product's NRL content provided by the manufacturer on a voluntary basis only. It is hoped this review article will act as a basic guide in the management of NRL-sensitive patients undergoing cataract surgery in the United Kingdom.

Aged↗
PubMed2003

Epidemic kerato-conjunctivitis--do outbreaks have to be epidemic?

PURPOSE: To study: the epidemiology of an outbreak of adenoviral keratoconjunctivitis in a UK teaching hospital; disease presentation and its effect on clinical diagnostic efficiency; patterns of viral transmission between staff and patients; the effectiveness of infection control procedures in minimising outbreaks. METHODS: Prospective/retrospective clinical audit and retrospective audit of virological culture results: all viral culture swabs taken during an outbreak of adenoviral keratoconjunctivitis were analysed. The case records of patients whose viral swabs were positive for adenoviral culture were traced. The time for viral cultures to become positive (culture positive time) was calculated. Analysis of the case notes was performed to elucidate (1) the source of infection and (2) the risk factors for acquisition of the infection. Retrospective clinical audit was performed to evaluate the effectiveness of infection control procedures. Adenovirus isolates underwent serotyping. RESULTS: During the 3-month period of study, there were 38 confirmed cases of adenoviral keratoconjunctivitis. This represented a 217% increase in the number of new cases per 3-month period. The case notes for five patients were untraceable. Of the remaining 33 patients, 21 (63%) had acquired their infection either directly or indirectly from the eye department and 22 (67%) had presented with unilateral disease. The rate of misdiagnosis was higher (9/22=42%) in patients presenting with unilateral disease than those presenting with bilateral disease (2/11=18%). Intradepartmental acquisition of infection was associated with invasive procedures, for example use of diagnostic/therapeutic contact lenses. Culture positive times ranged from 3 to 29 days. The introduction of infection control procedures was associated with a dramatic decrease in the incidence of departmentally acquired cases with no new cases after 2 weeks. Multiple serotypes of adenovirus were involved. CONCLUSION: Outbreaks of adenoviral keratoconjunctivitis are a serious public health issue concerning ophthalmic departments. This audit study illustrates several important points: (1) how hospital-acquired infection can account for a significant proportion of the cases seen, (2) how multiple types of adenovirus can be involved in a single outbreak, (3) that severe unilateral disease is associated with a higher rate of misdiagnosis; and (4) how standard viral culture techniques may not be satisfactory in confirming/disproving infection when the diagnosis is in doubt. The potential benefit of infection control procedures in minimising this outbreak could not be proven within this audit.

Adenoviridae↗
PubMed2003

A comparison of the ProSeal and classic laryngeal mask airways for airway management by inexperienced personnel after manikin-only training.

We compared the ProSeal (PLMA) and Classic (LMA) laryngeal mask airway for airway management by inexperienced personnel. Nine nurses from the post-anaesthesia care unit, with no prior experience of LMA or PLMA insertion, were observed inserting the LMA and PLMA in 60 ASA 1 to 2 anaesthetized, paralyzed adults following manikin-only training. The time to achieve an effective airway (2 consecutive expired tidal volumes (6 ml/kg; maximum 2 minutes allowed), the number of insertion attempts and the reasons for failure (inability to insert into pharynx or inadequate ventilation) were determined by analysis of digital video recordings. The first attempt success rate (LMA, 85%; PLMA, 83%), overall success rate (LMA, 88%; PLMA, 90%) and effective airway time (LMA, 39 +/- 13 s; PLMA, 43 +/- 19 s) were similar. Failure was from an inability to insert into the pharynx in five with the LMA and three with the PLMA, and inadequate ventilation with two from the LMA and three from the PLMA. Effective airway time and the number of failures were similar for the first and second device. Failure of both devices occurred in four patients. We conclude that airway management in anaesthetized, paralyzed adults is equally successful for the LMA and PLMA by inexperienced personnel following manikin-only training. The PLMA is worthy of consideration as a tool for emergency airway management by inexperienced personnel.

Adult↗
PubMed2001

Absence of a significant linkage between Na(+),K(+)-ATPase subunit (ATP1A3 and ATP1B3) genotypes and bipolar affective disorder in the old-order Amish.

Previous studies provide evidence for a genetic component for susceptibility to bipolar affective disorder (BPAD) in the old-order Amish population. El-Mallakh and Wyatt [1995: Biol Psychiatry 37:235-244] have suggested that the Na(+),K(+)-ATPase may be a candidate gene for BPAD. This study examines the relationship between BPAD in the old-order Amish cohort and the Na(+),K(+)-ATPase alpha1 and beta3 subunit genes (ATP1A3, ATP1B3). A total of 166 sibling pairs were analyzed for linkage via nonparametric methods. Suggestive levels of statistical significance were not reached in any stratification model for affective illness. Overall, the results do not support linkage of bipolar disorder to the Na(+),K(+)-ATPase alpha subunit gene (ATP1A3) and beta subunit gene (ATP1B3) in these old-order Amish families and they show that these Na(+),K(+)-ATPase subunit genes are not major effect genes (>or=fourfold increased genetic risk of disease) for BPAD in the old-order Amish pedigrees. We cannot exclude other genetic variants of the Na(+),K(+)-ATPase hypothesis for BPAD, whereby other loci may modifying Na(+),K(+)-ATPase activity.

Bipolar Disorder↗
PubMed2001

Preclinical evaluation of docusate as protective agent from herpes simplex viruses.

Prevention of sexually transmitted infections (STIs) is key to public health efforts to control these diseases. An effective vaginal microbicide could provide topical, broad-spectrum prevention against the transmission of several STI pathogens. Docusate is a sulfated surfactant and, as such, may inactivate viral pathogens by disrupting viral envelopes and/or denaturing/disassociating proteins. Accordingly, the in vitro efficacy and toxicity of docusate (dioctyl sodium sulfosuccinate; Zorex; Meditech Pharmaceuticals, Inc., Scottsdale, Arizona) against herpes simplex viruses (HSV) were evaluated. Docusate was effective in vitro against wild type and drug-resistant strains of HSV type 1 and 2 with EC(90-100) (effective concentration giving 90-100% virus yield reduction) of approximately 0.005% (w/v). Sodium dodecyl sulfate (SDS) was equipotent, however, docusate was somewhat less toxic to uninfected Vero cells compared with SDS after 2 days incubation (docusate CC(50) approximately 0.01% vs. SDS approximately 0.005%). The cytotoxicity profiles of docusate were time- and dose-dependent and thus associated with the frequency of use. Kinetics of inactivation examined by pre-mixing virus and drug in a time-course experiment demonstrated that docusate could reach its EC(90-100) within 30 min. Docusate pretreatment of cells was associated with a 45% reduction in infectivity of those cells, despite a triple washing procedure. Once infected, an approximate 30% plaque reduction was observed with treatment.

Animals↗
PubMed2000

Effects of biatrial pacing in prevention of postoperative atrial fibrillation after coronary artery bypass surgery.

BACKGROUND: Atrial fibrillation (AF) is common after coronary artery bypass surgery (CABG) and results in prolonged hospitalization. The purpose of this study was to evaluate the efficacy of biatrial pacing in preventing post-CABG AF compared with single-site atrial pacing. METHODS AND RESULTS: A total of 132 patients who had no history of AF and who underwent CABG were randomized to 1 of the following 4 groups: biatrial pacing (BiA), left atrial pacing (LA), right atrial pacing (RA), or no pacing (control) in postoperative period. Overdrive atrial pacing was performed for 5 days. The incidence of AF was significantly reduced in the BiA group (12.5%) compared with the other 3 groups (LA, 36.4%; RA, 33.3%; control, 41. 9%; P<0.05). The mean length of hospital stay was significantly reduced in the BiA group. At baseline, the mean P-wave duration (P(dur)) and dispersion (P(dis)) were not prolonged. BiA pacing resulted in the most significant percentage of reduction in P(dis) when compared with the LA or RA groups (BiA, 42+/-8%; LA, 13+/-6%; RA, 10+/-9%; P<0.05 for BiA versus LA or RA). No significant differences existed in mean P(dur) and P(dis) between patients who developed AF and those who remained in sinus rhythm at baseline. However, only those patients who remained in sinus rhythm had a significant reduction in mean P(dur) and P(dis) after pacing therapy. CONCLUSIONS: Biatrial overdrive pacing is more effective in preventing post-CABG AF than single-site atrial pacing; this therapy also results in a shortened hospital stay. The overall reduction in atrial activation time with BiA pacing was reflected in the reduction in P(dis).

Aged↗
PubMed1998

Repair of ruptured sinus of valsalva aneurysm: determinants of long-term survival.

BACKGROUND: Ruptured sinus of Valsalva aneurysm is a rare cardiac anomaly and long-term survival after surgical treatment is not well established. This study was designed to investigate the determinants of long-term survival after repair of ruptured sinus of Valsalva aneurysm. METHODS: From April 1978 to April 1996, 53 patients underwent operation for ruptured sinus of Valsalva aneurysm. The incidence among our cardiac surgical population was 0.56%. Long-term survival was investigated in 46 patients (13 to 65 years) who survived the operation, with 96.2% follow-up completeness (mean+/-standard deviation, 6.5+/-4.9 years; maximum, 17.2 years), by univariate and multivariate analyses. RESULTS: There was no early operative death and no recurrence after the initial repair. Actuarial survival was 83.8%+/-8.4% at 15 years. Reoperation, aneurysm draining into the left ventricle, aortic prosthetic dehiscence, bacterial endocarditis, and aortic cross-clamp time (<70 minutes) were significant factors in long-term survival (p < 0.05). Multivariate analysis revealed that only aortic prosthesis dehiscence was the significant factor influencing late survival (p = 0.0001). CONCLUSIONS: Surgical treatment for ruptured sinus of Valsalva aneurysm is safe and has satisfactory results. Aortic prosthesis dehiscence is the independent determinant for long-term survival. Other factors including bacterial endocarditis, concomitant ventricular septal defect repair, and aortic valve replacement did not independently influence long-term survival.

Adolescent↗
PubMed1998

Biopatch--a new concept in antimicrobial dressings for invasive devices.

A randomised controlled trial (RCT) was conducted to assess the reduction in the rate of catheter-related infections associated with the Biopatch dressing (Johnson & Johnson Medical Inc., Arlington, Texas, USA) used for insertion-site management of central venous catheters (CVCs) placed in the intensive care unit. Patients having a CVC placed were randomly assigned to receive either a Biopatch keyhole dressing to the occlusive Opsite IV 3000 (Smith and Nephew Medical Ltd., Hull, UK) (experimental group) or the Opsite IV 3000 alone (control group). There was a very low colonisation rate of CVC tip and skin exit-site swabs in both the experimental group (6 of 17) and the control group (5 of 16). No statistical difference was found between the two groups with regard to CVC or exit-site colonisation. A calculated sample size of 11,000 would be required to statistically demonstrate a 10 per cent reduction in CVC infection rate using the new Biopatch dressing. A much larger RCT would be required to demonstrate the efficacy of this new device.

Adult↗