Management of patients admitted with pneumothorax: a multi-centre study of the practice and outcomes in Hong Kong

ABSTRACT
Hong Kong Med J 2009;15:427-33 | Number 6, December 2009
ORIGINAL ARTICLE
Management of patients admitted with pneumothorax: a multi-centre study of the practice and outcomes in Hong Kong
Johnny WM Chan, Fanny WS Ko, CK Ng, Alwin WT Yeung, Wilson KS Yee, Loletta KY So, B Lam, Maureen ML Wong, KL Choo, Alice SS Ho, PY Tse, SL Fung, CK Lo, WC Yu
Department of Medicine, Queen Elizabeth Hospital, Hong Kong
 
 
OBJECTIVE. To examine the management practice of pneumothorax in hospitalised patients in Hong Kong, especially the choice of drainage options and their success rates, as well as the factors associated with procedural failures.
 
DESIGN. Retrospective study.
 
SETTING. Multi-centre study involving 12 public hospitals in Hong Kong.
 
PATIENTS. All adult patients admitted as an emergency in the year 2004 with a discharge diagnosis of 'pneumothorax' were included. Data on the management and outcomes of the various types of pneumothoraces were collected from their case records.
 
RESULTS. Altogether these patients had 1091 episodes (476 primary spontaneous pneumothoraces, 483 secondary spontaneous pneumothoraces, 87 iatrogenic pneumothoraces, and 45 traumatic pneumothoraces). Conservative treatment was offered in 182 (17%) episodes, which were more common among patients with small primary spontaneous pneumothoraces (71%). Simple aspiration was performed to treat 122 (11%) of such episodes, and had a success rate of 15%. Aspiration failure was associated with having a pneumothorax of size 2 cm or larger (odds ratio=3.7; 95% confidence interval, 1.2-11.5; P=0.03) and a smoking history (4.1; 1.2-14.3; P=0.03). Intercostal tube drainage was employed in 890 (82%) episodes, with a success rate of 77%. Failure of intercostal tube drainage was associated with application of suction (odds ratio=4.1; 95% confidence interval, 2.8-5.9; P<0.001) and presence of any tube complications (1.55; 1.0-2.3; P=0.03). Small-bore catheters (<14 French) were used in 12 (1%) of the episodes only. Tube complications were encountered in 214 (24%) episodes.
 
CONCLUSION. Notwithstanding recommendations from international guidelines, simple aspiration and intercostal tube drainage with small-bore catheters were not commonly employed in the management of hospitalised patients with the various types of pneumothoraces in Hong Kong.
 
Key words: Chest tubes; Drainage; Pneumothorax/therapy; Suction; Treatment outcome
 
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Frozen-thawed embryo transfer cycles

ABSTRACT
Hong Kong Med J 2009;15:420-6 | Number 6, December 2009
ORIGINAL ARTICLE
Frozen-thawed embryo transfer cycles
William SB Yeung, Raymond HW Li, TM Cheung, Ernest HY Ng, Estella YL Lau, PC Ho
Centre of Assisted Reproduction and Embryology, Department of Obstetrics and Gynaecology, The University of Hong Kong, Queen Mary Hospital, 102 Pokfulam Road, Hong Kong
 
 
OBJECTIVE. To review the outcomes of frozen-thawed embryo transfer cycles.
 
DESIGN. Retrospective review.
 
SETTING. Tertiary assisted reproduction centre, Hong Kong.
 
PATIENTS. Subfertile patients undergoing frozen-thawed embryo transfer between July 2005 and December 2007.
 
MAIN OUTCOME MEASURES. Clinical and ongoing pregnancy rates.
 
RESULTS. A total of 983 frozen-thawed embryo transfer cycles performed during the study period were reviewed. The clinical pregnancy and ongoing pregnancy rates were 35% and 30%, respectively. Factors associated with successful outcome included younger maternal age (<=35 years) and 4 or more blastomeres at replacement, but not the method of insemination, the cause of subfertility, or the type of frozen-thawed embryo transfer cycle. The overall multiple pregnancy rate was 18%. For cycles with a single embryo replaced, embryos having 4-cell or higher stages at replacement gave an ongoing pregnancy rate of 25%, whereas those with less than 4 cells had a significantly lower ongoing pregnancy rate of 5% only. Blastomere lysis after thawing significantly reduced the clinical pregnancy and ongoing pregnancy rates of cycles with one embryo replaced.
 
CONCLUSIONS. Clinical pregnancy and ongoing pregnancy rates of frozen-thawed embryo transfer cycles were 35% and 30%, respectively. Higher pregnancy rates were associated with younger maternal age (<=35 years), blastomere numbers of 4 or more, and no blastomere lysis after thawing.
 
Key words: Cryopreservation; Embryo transfer; Fertilization in vitro
 
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Change in prevalence of group B Streptococcus maternal colonisation in Hong Kong

ABSTRACT
Hong Kong Med J 2009;15:414-9 | Number 6, December 2009
ORIGINAL ARTICLE
Change in prevalence of group B Streptococcus maternal colonisation in Hong Kong
Michelle HY Tsui, Margaret Ip, PC Ng, Daljit S Sahota, TN Leung, TK Lau
Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong
 
 
OBJECTIVES. To re-examine the prevalence of group B Streptococcus colonisation in our antenatal population, and identify demographic factors associated with carriage.
 
DESIGN. Prospective observational study.
 
SETTING. A tertiary obstetrics unit in Hong Kong.
 
PARTICIPANTS. A total of 1002 pregnant women were recruited at the booking clinic in a tertiary obstetrics unit in Hong Kong. High and low vaginal swabs and rectal swabs were taken for group B Streptococcus culture. Demographic data and delivery outcomes of the recruits were analysed.
 
RESULTS. The prevalence of group B Streptococcus colonisation in our antenatal population was 10.4%. The majority of carriers were identified by low vaginal swabs (78%), while high vaginal swabs and rectal swabs only identified 31% and 30% of the carriers, respectively. Professional women yielded a higher carrier rate than housewives (21% vs 10%, P=0.03). There was no increase in preterm delivery rate in group B Streptococcus carriers.
 
CONCLUSIONS. We noted a dramatic increase in the prevalence of group B Streptococcus colonisation in the Hong Kong pregnant population at their booking visit. Professional women had a higher colonisation rate compared to other groups.
 
Key words: Pregnancy complications, infectious; Streptococcal infections; Streptococcus agalactiae; Vaginal smears
 
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Use of Onyx (a patented ethylene-vinyl alcohol copolymer formulation) embolisation of cerebral arteriovenous malformations in Hong Kong: initial experience

ABSTRACT
Hong Kong Med J 2009;15:359-64 | Number 5, October 2009
ORIGINAL ARTICLE
Use of Onyx (a patented ethylene-vinyl alcohol copolymer formulation) embolisation of cerebral arteriovenous malformations in Hong Kong: initial experience
George KC Wong, Simon CH Yu, XL Zhu, Michael KM Kam, WS Poon
Division of Neurosurgery, Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong
 
 
OBJECTIVE. To review the experience with Onyx embolisation of cerebral arteriovenous malformation.
 
DESIGN. Prospective study.
 
SETTING. A regional neurosurgical centre in Hong Kong.
 
PATIENTS. Data of patients with cerebral arteriovenous malformation who underwent Onyx embolisation over a 14-month period were prospectively collected.
 
RESULTS. Eleven sessions of Onyx embolisation were performed in nine patients with cerebral arteriovenous malformations, seven of which had ruptured. Total occlusion was achieved in three (33%) of the patients, and subtotal occlusion (over 80% occlusion) in three out of four with Spetzler-Martin grade-III/IV malformations. One patient developed mild permanent neurological deficit.
 
CONCLUSION. Onyx embolisation of cerebral arteriovenous malformations is feasible in Hong Kong. Careful patient and target selection are important.
 
Key words: Embolization, therapeutic; Intracranial arteriovenous malformations; Polyvinyls; Treatment outcome
 
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Imageless computer navigation in total knee arthroplasty

ABSTRACT
Hong Kong Med J 2009;15:353-8 | Number 5, October 2009
ORIGINAL ARTICLE
Imageless computer navigation in total knee arthroplasty
KW Cheung, KH Chiu
Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong
 
 
OBJECTIVES. To study the difference in clinical and radiological outcomes between imageless computer-navigated and the conventional technique for performing total knee arthroplasty.
 
DESIGN. Prospective case-control study.
 
SETTING. University teaching hospital, Hong Kong.
 
PATIENTS. Forty-seven patients with imageless computer-navigated total knee arthroplasty were matched with 47 patients with total knee arthroplasty using conventional technique over the period 2003 to 2007.
 
MAIN OUTCOME MEASURES. Postoperative radiological alignment, tourniquet time, Knee Society knee score and functional score, and range of motion.
 
RESULTS. The femoral anteroposterior, tibial anteroposterior, overall anteroposterior alignment of the lower limb, and lateral femoral lateral flexion angle had significantly less deviation from neutral alignment in those having computer-assisted total knee arthroplasty than conventional total knee arthroplasty. The former had significantly fewer outliers (>3 degrees from neutral alignment) than the latter, in both the coronal and sagittal planes of the femoral and tibial sides. The mean tourniquet time was significantly longer in the former (111 minutes) than in those having a conventional arthroplasty (98 minutes). There was no tracker/pin tract complication or wound infection in either group.
 
CONCLUSION. Computer-assisted navigation can give a better alignment than the conventional technique, but the tourniquet time was significantly longer. Computer-assisted navigation surgery can help the surgeon in determining limb alignment during the operation.
 
Key words: Arthroplasty, replacement, knee; Recovery of function; Surgery, computer-assisted
 
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Airway inflammatory and spirometric measurements in obese children

ABSTRACT
Hong Kong Med J 2009;15:346-52 | Number 5, October 2009
ORIGINAL ARTICLE
Airway inflammatory and spirometric measurements in obese children
Joyce SW Chow, Amelia SM Leung, Wincy WS Li, Teresa PK Tse, HY Sy, TF Leung
Faculty of Medicine, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong
 
 
OBJECTIVES. To investigate the association between obesity and airway inflammation and spirometric parameters in local children.
 
DESIGN. Cross-sectional and observational study.
 
SETTING. Paediatric clinics of a university-affiliated teaching hospital in Hong Kong.
 
PATIENTS. Chinese subjects aged 6 to 18 years were recruited from the paediatric clinics. Obesity was defined as being 120% or more of the median weight-for-height.
 
MAIN OUTCOME MEASURES. Airway inflammation assessed by exhaled nitric oxide concentration; lung function evaluated by measuring forced expiratory flow in 1-second and forced vital capacity using spirometry; and peak expiratory flow rate measured by using a mini-Wright peak flow meter.
 
RESULTS. Fifty-five subjects were recruited into four groups as follows: 13 non-obese controls, 16 obese non-asthmatics, 15 non-obese asthmatics, and 11 obese asthmatics. The median (interquartile range) exhaled nitric oxide concentrations of these groups were 17.6 (14.4-20.9), 33.3 (26.1-75.4), 65.7 (32.0-110.0) and 49.2 (41.1-82.6) parts per billion, respectively (P=0.001 for trend). Post-hoc analysis revealed higher exhaled nitric oxide concentration in the latter three groups (obese and/or asthmatic subjects) than controls (P<=0.002). Exhaled nitric oxide concentration did not differ among obese non-asthmatics, non-obese asthmatics, and obese asthmatics (P>0.1 for all). In non-asthmatics, exhaled nitric oxide concentration correlated positively with age (P=0.048), weight-for-height z-score (P=0.001), and forced vital capacity (P=0.009). Weight-for-height z-score correlated positively with forced vital capacity (P=0.041), but inversely with the forced expiratory flow in 1-second/forced vital capacity ratio (P=0.049). Such correlations were not observed in asthmatic children.
 
CONCLUSION. Increased airway inflammation as revealed by exhaled nitric oxide concentration was found in obese non-asthmatic children. Weight-for-height z-score as an indicator of childhood obesity correlated with exhaled nitric oxide concentration and spirometric parameters in children without asthma. Nonetheless, concomitant obesity does not influence exhaled nitric oxide concentration in asthmatic children. Further studies are needed to identify the pathophysiologic mechanisms for such associations.
 
Key words: Asthma; Bronchitis; Child; Obesity; Spirometry
 
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Outcome of inoperable hepatocellular carcinoma patients receiving transarterial chemoembolisation: a real-life retrospective analysis in a Hong Kong regional hospital

ABSTRACT
Hong Kong Med J 2009;15:339-45 | Number 5, October 2009
ORIGINAL ARTICLE
Outcome of inoperable hepatocellular carcinoma patients receiving transarterial chemoembolisation: a real-life retrospective analysis in a Hong Kong regional hospital
WM Yip, HG Hung, KH Lok, KF Li, KK Li, ML Szeto
Division of Gastroenterology and Hepatology, Department of Medicine and Geriatrics, Tuen Mun Hospital, Tuen Mun, Hong Kong
 
 
OBJECTIVE. To evaluate survival and prognostic factors in patients with advanced hepatocellular carcinoma treated by transarterial chemoembolisation in a real-life clinical practice setting.
 
DESIGN. Retrospective study.
 
SETTING. Regional hospital, Hong Kong.
 
PATIENTS. Patients with inoperable hepatocellular carcinoma diagnosed from January 1998 to December 2003 who received transarterial chemoembolisation.
 
RESULTS. A total of 74 patients were identified, and had a median survival of 214 days. The cumulative survival rates at 1, 2, and 3 years were 28%, 12%, and 7%, respectively. By multivariate analysis, superselective cannulation performed in transarterial chemoembolisation (hazard ratio=0.47; 95% confidence interval, 0.23-0.95; P=0.034), embolisation with gelfoam (0.30; 0.11-0.80; P=0.017), and treatment intervals of more than 45 days (0.33; 0.15-0.72; P=0.006) were independent predictors of good survival. Child-Pugh grade B cirrhosis (hazard ratio=5.62; 95% confidence interval, 2.11-14.97; P=0.001), and high pre-treatment serum alpha-fetoprotein level (2.93; 1.50-5.73; P=0.002) were independent predictors of poor survival.
 
CONCLUSIONS. In real-life clinical practice, survival of patients with inoperable hepatocellular carcinoma remains grave despite treatment. Patients with Child-Pugh grade A cirrhosis or with low pretreatment alpha-fetoprotein level are more suitable for this form of treatment. The procedure should be performed with superselective cannulation and embolisation with gelfoam.
 
Key words: Carcinoma, hepatocellular; Chemoembolization, therapeutic; Liver neoplasms; Prognosis; Survival rate
 
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Competence in evidence-based medicine of senior medical students following a clinically integrated training programme

ABSTRACT
Hong Kong Med J 2009;15:332-8 | Number 5, October 2009
ORIGINAL ARTICLE
Competence in evidence-based medicine of senior medical students following a clinically integrated training programme
NM Lai, CL Teng
Department of Paediatrics, School of Medicine and Health Sciences, Monash University Malaysia, JKR 1235, Bukit Azah, 80100, Johor Bahru, Johor Darul Takzim, Malaysia
 
 
OBJECTIVE. To assess the impact of a structured, clinically integrated evidence-based undergraduate medicine training programme using a validated tool.
 
DESIGN. Before and after study with no control group.
 
SETTING. A medical school in Malaysia with an affiliated district clinical training hospital.
 
PARTICIPANTS. Seventy-two medical students in their final 6 months of training (senior clerkship) encountered between March and August 2006.
 
INTERVENTION. Our educational intervention included two plenary lectures at the beginning of the clerkship, small-group bedside question-generating sessions, and a journal club in the paediatric posting.
 
MAIN OUTCOME MEASURES. Our primary outcome was evidence-based medicine knowledge, measured using the adapted Fresno test (score range, 0-212) administered before and after the intervention. We evaluated the performance of the whole cohort, as well as the scores of different subgroups that received separate small-group interventions in their paediatric posting. We also measured the correlation between the students' evidence-based medicine test scores and overall academic performances in the senior clerkship.
 
RESULTS. Fifty-five paired scripts were analysed. Evidence-based medicine knowledge improved significantly post-intervention (means: pre-test, 84 [standard deviation, 24]; post-test, 122 [22]; P<0.001). Post-test scores were significantly correlated with overall senior clerkship performance (r=0.329, P=0.014). Lower post-test scores were observed in subgroups that received their small-group training earlier as opposed to later in the clerkship.
 
CONCLUSIONS. Clinically integrated undergraduate evidence-based medicine training produced an educationally important improvement in evidence-based medicine knowledge. Student performance in the adapted Fresno test to some extent reflected their overall academic performance in the senior clerkship. Loss of evidence-based medicine knowledge, which might have occurred soon after small-group training, is a concern that warrants future assessment.
 
Key words: Education, medical, undergraduate; Evidence-based medicine
 
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Prophylactic thyroidectomy in ethnic Chinese patients with multiple endocrine neoplasia type 2A syndrome after the introduction of genetic testing

ABSTRACT
Hong Kong Med J 2009;15:326-31 | Number 5, October 2009
ORIGINAL ARTICLE
Prophylactic thyroidectomy in ethnic Chinese patients with multiple endocrine neoplasia type 2A syndrome after the introduction of genetic testing
Gregory SK Lau, Brian HH Lang, CY Lo, Annette Tso, Merce M Garcia-Barcelo, Paul K Tam, Karen SL Lam
Department of Surgery, University of Hong Kong Medical Centre, Queen Mary Hospital, Pokfulam Road, Hong Kong
 
 
OBJECTIVE. To evaluate the impact of genetic testing in the management of familial multiple endocrine neoplasia 2A patients.
 
DESIGN. Retrospective study.
 
SETTING. University teaching hospital, Hong Kong.
 
PATIENTS. Twenty-two patients from eight multiple endocrine neoplasia 2A families underwent prophylactic total thyroidectomy based on a positive RET mutation genetic testing. All mutations were located at codon 634 of exon 11. Nineteen patients had preoperative basal serum calcitonin measured, and the 12 with normal levels had pentagastrin stimulation tests. Preoperative thyroid ultrasound examination was performed for 17 patients.
 
RESULTS. There were 13 females and 9 males with a median age of 25.1 (range, 6.1-71.9) years. Histopathology revealed medullary thyroid carcinoma in 17 (77%), C-cell hyperplasia in four (18%), and normal pathology in one (5%) of the patients. Five patients with either C-cell hyperplasia or normal pathology were among the youngest (age range, 6-9 years). The youngest patient with medullary thyroid carcinoma was nearly 9 years old. The median size of medullary thyroid carcinomas was 8.3 (range, 0.1-18) mm, but there were no lymph node metastases. Of 15 patients with normal basal calcitonin levels, 10 had medullary thyroid carcinoma, though two tested negative with the pentagastrin-stimulated calcitonin assay. Five of six patients with normal preoperative ultrasonographic examinations had medullary thyroid carcinoma. Three (14%) of the patients were prescribed long-term calcium and vitamin D supplementation. After a median follow-up of 49 (range, 13-128) months, no patient had recurrence of medullary thyroid carcinoma.
 
CONCLUSIONS. Genetic testing has replaced conventional biochemical and radiological modalities to identifying multiple endocrine neoplasia 2A carriers, in order to offer them prophylactic thyroidectomy. Chinese multiple endocrine neoplasia 2A patients with codon 634 mutation seem to have less aggressive forms of medullary thyroid carcinoma, for whom prophylactic thyroidectomy can be considered at the age of 8 years.
 
Key words: Genetic screening; Multiple endocrine neoplasia type 2a; Proto-oncogene proteins c-ret; Thyroid neoplasms; Thyroidectomy
 
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Limb lengthening in short-stature patients using monolateral and circular external fixators

ABSTRACT
Hong Kong Med J 2009;15:280-4 | Number 4, August 2009
ORIGINAL ARTICLE
Limb lengthening in short-stature patients using monolateral and circular external fixators
Chester WH Lie, W Chow
Department of Orthopaedics and Traumatology, Duchess of Kent Children's Hospital, Pokfulam, Hong Kong
 
 
OBJECTIVES. To review the results of distraction osteogenesis in short-stature patients in our centre and analyse outcomes including complications.
 
DESIGN. Retrospective study.
 
SETTING. University teaching hospital, Hong Kong.
 
PATIENTS. Eight patients with short stature (three had achondroplasia, three constitutional short stature, and two hypochondroplasia) operated on for limb lengthening using monolateral or circular external fixators between 1995 and 2006 were reviewed.
 
RESULTS. The mean age at the time of surgery was 20 years (range, 9-39 years). The fixators used were either Ilizarov or Orthofix. The average gain in length per bone segment was 5.2 cm (range, 3.2-8.0 cm), and the average percentage lengthening was 21% (range, 7.9-40%). The mean time in frame was 8 months (range, 4-14 months), and the average healing index was 48 days per cm of lengthening (18-110 days per cm). Minor complications (pin tract infection and transient joint stiffness) were common, and after excluding the latter the overall complication rate was 0.6 per bone segment.
 
CONCLUSION. In our series, limb lengthening of up to 40% of the initial length of the bone segment can be achieved without significant long-term sequelae. However, the procedures were complex and prolonged, and required a special psychological approach directed at both parents and the patients. Complications are quite common, for which patients have to be well prepared before starting the procedures.
 
Key words: Body height; Bone lengthening; Ilizarov technique; Leg/growth & development; Osteogenesis, distraction
 
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