Silicone oil (SO) is widely used as the long-term intraocular tamponade in treating various eye diseases such as complicated retinal detachment, proliferative vitreoretinopathy, proliferative diabetic retinopathy, giant retinal tear and ocular trauma. However, its propensity to emulsify is an inherent problem of its long-term use in-vivo. Dispersal of SO into many tiny oil droplets causes numerous complications such as inflammation, glaucoma and reproliferation. It may also be responsible for possible toxicity to both retina and optic nerve. Emulsification is one of the problems associated to the use of SO as a long-term intraocular tamponade. This study focused on the understanding on the physical nature and formation of in-vivo SO emulsion and the development of methods to reduce the complications associated with emulsification of SO by engineering approaches. A stepper motor driven mechanical platform was built to study the fluid flow of SO within an eye model chamber during eye-like movements and a quantitative method was established to study SO emulsification, both in-vivo and in-vitro. This method was used to compare the relative resistance of different SO against emulsification. In the last part of the thesis a novel rinse was proposed which aimed at removing the emulsified SO droplets in-vivo in an effective way. In the dynamic eye model experiment, both the increase in shear viscosity of SO and the extent of SO fill had an effect in reducing the shear. These effects were small compared to the effect of indents at reducing shear rate during eye-like movements. When SO emulsions from patients were analyzed it was found that over 90% of the emulsified droplets were outside the observable range under slit-lamp biomicroscopy. When the emulsification resistance of SO was tested using the quantitative method the result confirmed that SO with high-molecular-weight component (HMWC) was more emulsification resistant than SO with the same shear viscosity. The addition of HMWC increases the elasticity and thus increasing its resistance against emulsification. A novel rinse was also proposed to remove the emulsified droplets using physical phenomenon of double emulsification. To conclude, this study improved the understanding of the formation of SO emulsification. The clinical observable emulsified droplets are probably in all cases that was just the tip of the iceberg. Three practical suggestions were made: Firstly, the use of SO and encircling scleral buckling procedure in combination might reduce the shear rate. Secondly, the use of HMWC can reduce emulsification. Lastly, there may be a role in rinsing out the emulsified droplets using the proposed novel solution. The novel solution is going to fully developed and commercialized in the near future. / published_or_final_version / Ophthalmology / Doctoral / Doctor of Philosophy

No description available.

Objectives: To report the incidence of objective and subjective neurosensory disturbance (NSD) after orthognathic surgery in a major orthognathic centre in Hong Kong, and to investigate the risk factors that contributed to the incidence of NSD after orthognathic surgery. Materials and Methods: A retrospective cross-sectional study on NSD after orthognathic surgery in a local major orthognathic centre. Patients who had bimaxillary orthognathic surgery reviewed at post-operative 6 months, 12 months or 24 months were recruited to undergo a neurosensory test with subjective and 3 objective assessments. Possible risk factors of NSD including subjects’ age and gender, surgical procedures and surgeons’ experience were analyzed. Results: 238 patients with 476 sides each of maxillary and mandibular procedures were recruited. The incidences of subjective NSD after maxillary procedures were 16.2%, 13% and 9.8% at post-operative 6 months, 12 months and 24 months, respectively; the incidences of subjective NSD after mandibular procedures were 35.4%, 36.6% and 34.6% at post-operative 6 months, 12 months and 24 months, respectively. Objective neurosensory tests showed general reduced sensitivity in subjects with subjective NSD. Increased age was found to be a significant risk factor of NSD after orthognathic surgery at short term (at 6 months and 12 months) but not at 24 months. SSO has a significantly higher risk of NSD when compared to VSSO. SSO in combination with anterior mandibular surgery has a higher risk of NSD when compared to VSSO in combination with anterior mandibular surgery or anterior mandibular surgery alone. Gender of patients a nd surgeons’ experience were not found to be risk factors of NSD after orthognathic surgery. Conclusion: The incidence of NSD after maxillary and mandibular orthognathic procedures at post-operative 6 months, 12 months and 24 months was reported. Increased age was identified as a risk factor of short term post-operative NSD but not in long term (24 months or more). Specific mandibular procedures were related to higher incidence of NSD after orthognathic surgery. / published_or_final_version / Dental Surgery / Master / Master of Dental Surgery

Indiana University-Purdue University Indianapolis (IUPUI) / Complications following intestinal ostomy surgery can diminish quality of life for individuals living with an ostomy, resulting in physical and psychosocial limitations. Risk factors contributing to ostomy complications are not well established in the literature. The purposes of this study were to: 1) identify risk factors contributing to the development of fecal ostomy complications; 2) describe the incidence and severity of early fecal ostomy complications; and 3) estimate the reliability and validity of two newly developed instruments, Ostomy Risk Factor Index (ORFI) and Ostomy Complication Severity Index (OCSI). Using a prospective longitudinal design, 71 adult patients who had undergone ostomy surgery were recruited from three acute care settings. Data were collected through self-administered surveys, medical record review, and direct observation prior to discharge and at 30 to 60 days post-operatively. Data were analyzed using descriptive statistics, analysis of variance, chi-square tests, correlation, and multiple regression. Psychometric properties of the Ostomy Risk Factor Index and the Ostomy Complication Severity Index were examined using content validity indices, Cohen coefficient kappa, Pearson correlation coefficient, and intra-class correlation. Two risk factors were found to be predictive of ostomy complications scores, stoma/abdomen characteristics (p= .007) and BMI (p= .002). Ostomy complications and ostomy adjustment were significantly inversely correlated (r= - 0.27, p=.04) and stoma care self-efficacy and ostomy adjustment were significantly correlated (r= .599, p= .01). The ORFI and OCSI demonstrated acceptable content validity (CVI= 0.9). ORFI demonstrated acceptable inter-rater reliability for 10 of the 14 items (k= 1.0) and excellent intraclass correlation of total scores between raters (r= .998, p= .001). The OCSI demonstrated acceptable inter-rater reliability for all of the items (k= .71- 1.0) and excellent intra-class vii correlation of total scores between raters (r= .991, p= .000). The OCSI demonstrated acceptable internal consistency (Cronbach's alpha .68). In conclusion, this study provides new knowledge regarding risk factors, incidence and severity of ostomy complications, and provided support for the validity and reliability of two new instruments for the researcher and practitioner to reliably identify and describe important contributors (risk factors) and outcomes (complications) that affect care of the patient with an ostomy.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Typescript (photocopy). / Digitized by Kansas Correctional Industries

The purposes of this research were to: (1) describe selected fluid and electrolyte changes that occur during the first four hours after open heart surgery; (2) determine whether significant hourly changes occurred in: blood pH, fluid intake, exogenous potassum chloride replacement, fluid output, or serum and urinary sodium and potassium levels; and finally, (3) delineate which of the above variables were most strongly related to changes in serum and urinary, sodium and potassium levels. Fifty-three patients who had undergone cardiac surgery involving cardiopulmonary bypass were studied. Urine and blood samples were collected every hour for the first four hours postoperatively and were analyzed for sodium and potassium content using flame photometry. Blood pH and exogenous potassium chloride replacement were recorded from the anesthesiologist's and nurse's records. Fluid intake and fluid output were measured directly by the investigator. Analyses included both descriptive and correlational statistics. In addition, a repeated measures procedure (MANOVA) was performed to discern performance trends over time. The data showed that hypokalemia (defined as a serum potassium level less than 4.0 mEq/L) was present in approximately 52 percent of the subjects for the first two postoperative hours and that by the fourth hour only 15 percent of the subjects were hypokalemic. In addition, subjects were noted to retain 2.47 liters of fluid over the four hour period. Significant differences in fluid output were noted across time. Serum sodium levels did not change significantly across time even though serum potassium levels did. The data indicated that the best predictors of hypokalemia were fluid intake and fluid output. Both of these variables had a significance level of p = .000. Regression analysis showed that fluid intake and exogenous potassium chloride replacement explained 11.9 percent of the variance in serum potassium at a significance level of p = .008. Furthermore, fluid output explained 7.3 percent of the variance in urinary potassium (p = .030).

According to the World Health Organisation, hip fracture among elderly people is a global public health problem, with 1.7 million cases worldwide in 1991, a figure due to the aging population and believed likely to increase. Post-operative delirium is a common complication following hip-fracture surgery, and occurs in 25% to 65% of cases (Gustafson 1988). It not only affects the rehabilitation progress of the elderly, but also prolongs hospitalisation, which in turn increases the financial burden on the government. There are different ways of managing post-operative delirium among the elderly, including pharmacological and multifactorial interventions and education programmes. However, there is no standard nursing management of post-operative delirium in Hong Kong, and this affects both patient care and nursing standards. According to the National Institute for Health and Clinical Excellence (2011), multifactorial intervention is cost-effective and an effective method of reducing postoperative delirium, where nurses play an important role as gatekeepers, and thus allow such intervention to be introduced into the clinical setting. With this in mind, translational nursing research was performed by a review of four studies, to introduce the concept of multifactorial intervention to nurses, to formulate the implementation for the intervention, and finally to obtain feedback from colleagues. / published_or_final_version / Nursing Studies / Master / Master of Nursing

No description available.

Renal failure in patients undergoing Aortic surgery is associated with a poor outcome. The shortcomings of serum creatinine for measuring renal function are well documented. We examined the value of alternative markers in diagnosing and predicting renal damage in patients undergoing abdominal aortic surgery and those exposed to intravascular contrast media. Cystatin C lacks some of the reservations associated with serum creatinine when used as a marker of glomerular filtration rate. The protease inhibitor alpha-glutathione Stransferase (a-GST) is recovered in urine after injury to proximal tubular cells. Urine microalbumin is a marker of glomerular permeability. Together we used all four assays to detect and characterize the nature of renal injury after surgery and contrast exposure. Cystatin C had a marginally better sensitivity than serum creatinine at detecting baseline renal impairment. It also showed earlier changes in individual patients whose renal dysfunction deteriorated over time. The urinary markers showed an earlier significant rise after the onset of surgery when compared to serum markers, but only a-GST rose significantly after contrast exposure. Patients undergoing a supra-renal cross-clamp showed significantly higher a-GST levels (and not the other three markers) when compared to the infra-renal group. Cystatin C appears to have better sensitivity and specificity for predicting the need for dialysis in patients undergoing surgery. Peak serum creatinine and cystatin C after contrast exposure show good correlation with peak values after surgery. Cystatin C is equivalent to and may be better than serum creatinine in detecting preexisting and deteriorating renal impairment. Although the urinary assays are earlier markers of renal injury, their clinical significance needs to be determined. Elevation in creatinine and cystatin C after contrast exposure parallel those after surgical intervention and may be helpful in selecting out high-risk patients prior to surgery. / Thesis (M.Med.Sc.)-University of Natal, 2003.