Original Article

LL Phoa, WY Pek, WS Yap, A Johan
Correspondence: Dr Phoa Lee Lan, lee_lan_phoa@ttsh.com.sg

ABSTRACT
Objectives To study the outcome of unplanned extubation (UE) in the Medical Intensive Care Unit (MICU) and to identify factors which predict the need for reintubation.
Methods A prospective study of all mechanically ventilated patients admitted to MICU in 1998. Patients were enrolled into the study at the point of their first UE. The primary endpoint was reintubation after UE and secondary endpoint was death from any cause during hospitalisation.
Results A total of 543 patients were admitted to MICU of which 312 were mechanically ventilated. UE accounted for 8.7% of our mechanically ventilated patients. The mean APACHE 11 score was 20 (+/- 10), mean time between intubation and UE was 3.1 days (+/- 3.1), mean length of MICU stay was 10.1 days (+/- 10.2) and mean hospital stay was 27.0 days (+/- 36.1). Eighty-seven percent of the UE was deliberate. The rate of reintubation after failed UE was 58.3% of which 71.4% had immediate reintubation. Twenty-nine percent of patients were undergoing weaning during UE. The in-hospital mortality was 25%. All deaths occurred in the group who failed UE. Patients who failed UE had a higher mean APACHE 11 score, a higher mean pre-extubation FiO2 level and a lower mean PaO2/ FiO2 ratio (p < 0.05).
Conclusion UE accounted for 8.7% of our mechanically ventilated patients and 58.3% of these patients required reintubation. Failed UE was associated with a higher mortality. A higher APACHE 11 score, higher pre-extubation FiO2 level and a lower PaO2/FiO2 ratio were associated with reintubation after failed UE.

Keywords: outcome, reintubation, mortality, predicting factors
Singapore Med J 2002; 43(10): 504-508

CE Ezenwaka, NV Offiah
Correspondence: Dr C E Ezenwaka, ezenwaka@ttst.net.tt

ABSTRACT
Objective To assess the cardiovascular disease (CVD) risk factors in elderly (> or = 60 years) and younger patients with Type 2 diabetes visiting two primary care clinics in Trinidad.
Materials and Methods Fasting blood samples were taken from one hundred and ninety-one (127 females, 64 males) patients with Type 2 diabetes visiting two primary care clinics between 1 January and 30 April 2000. Anthropometric indices, blood pressure, plasma glucose, serum lipids and insulin were measured. Homeostasis Model Assessment (HOMA) was used to assess basal insulin resistance (IR).
Results Of the 191 patients studied, 58.6% were <60 years old while 41.4% were > or = 60 years old. The younger patients had higher prevalence rates of cigarette smoking and use of alcoholic drinks (p < 0.05). The female younger patients had significantly higher mean body mass index (BMI), glycated haemoglobin (HbA1c), triglyceride, total-cholesterol, fasting plasma glucose and IR than the elderly female patients (p < 0.05). Similarly, the younger male patients had significantly higher mean HbA1c, creatinine, fasting plasma glucose, IR and lower HDL-cholesterol levels than the elderly male patients (p < 0.05). Generally, the younger patients had significantly higher prevalence rates of hypertriglyceridaemia, obesity, poorer glycaemia and blood pressure control.
Conclusion The results indicate that younger patients withType 2 diabetes had poorer metabolic control and higher prevalence rates of CVD risk factors than the elderly patients. The greater risk of CVD in younger patients was not independent of gender and ethnicity.

Keywords: cardiovascular disease, elderly, primary care, Type 2 diabetes
Singapore Med J 2002; 43(10): 497-503

LKP Yap, KHK Ow, JYR Hui, WS Pang
Correspondence: Dr L K P Yap, philip_yap@alexhosp.com.sg

ABSTRACT
Aim To determine the size of the problem of premature discharge in a community hospital (CH) and to ascertain the reasons for it.
Method A retrospective review of all admissions in year 2000 which resulted in premature discharge i.e. discharge within one week of admission, was conducted in a community hospital, St Luke's Hospital for the Elderly. Information collected on the selected cases included biodata, reason for CH stay, admitting diagnosis, source of admission, duration of stay and reason for terminating stay prematurely. For cases which required acute hospital transfer or ended in death in the CH, the type and day of onset of the respective medical problems were documented.
Results Out of 924 admissions in year 2000, 12% resulted in premature discharge. Within this category of patients, 54% were discharged within the first three days and median duration of stay was three days. Majority of the admissions were for rehabilitation (83%) and respite care (15%). Neurological (60%) and orthopaedic (18%) problems constituted the bulk of the admitting diagnoses. The main reason for premature discharge was acute hospital transfer (90%) for medically unstable patients and those with unresolved medical problems.
Conclusion Premature discharge in the CH is an important issue and the greater cause lies in the need to transfer medically unstable patients or patients with unresolved medical problems back to the acute hospital. Stricter enforcement of admission criteria into CHs, increased vigilance on the part of acute hospitals and implementation of subacute care in CH can be solutions to the problem.

Keywords: premature discharge, community hospital, subacute care, intermediate care, rehabilitation
Singapore Med J 2002; 43(9): 470-475

Mohan Tiru, SH Goh, BY Low
Correspondence: Dr Mohan Tiru, Mohan_Tiru@cgh.com.sg

ABSTRACT
Traumatic hip pain is a common clinical problem in the emergency department. There is significant morbidity in discharging a patient with an undiagnosed undisplaced hip fracture. The auscultatory percussion technique is a useful method to risk stratify patients who present with traumatic hip pain and with normal radiographs. We sought to study the sensitivity and specificity of the auscultatory percussion technique in a prospective study.

Keywords: Hip fracture, auscultatory percussion, normal radiography, sensitivity, specificity
Singapore Med J 2002; 43(9): 467-469

Michael Ong CC
Correspondence: Dr C C M Ong

ABSTRACT
Naval Medicine Hyperbaric Centre (NMHC) was approached by the Land Transport Authority (LTA) to provide medical support for the North Eastern Line MRT Project. The medical support provided by NMHC focused on providing training, audits and ensuring that safety and health infrastructure were in place even before the commencement of compressed air tunnelling. The extensive use of the EPBM (Earth Pressure Balance Machine) tunnelling machines for the first time in Singapore necessitated a reassessment of the medical support system and paradigm that was based primarily on the older form of tunnelling. The survey results showed that human exposure to compressed air works with the use of EPBM was minimal and no decompression illness was reported. However, there was still a total of 28 cases of barotrauma that were reported which were mainly from the tunnels dug using the open face compressed air tunnelling method. As such, medical providers should still exercise careful planning for the medical support of compressed air works.

Keywords: Underground tunnelling, Compressed air works, Earth Pressure Balance Machine, Decompression Sickness, Barotrauma
Singapore Med J 2002; 43(9): 463-466

LHY Lim, KC Soo, YK Chong, F Gao, GS Hong, TH Lim
Correspondence: Soo Khee Chee, admskc@nccs.com.sg

ABSTRACT
Aims 1) Determine the patient and tumour characteristics for well-differentiated thyroid carcinoma--towards developing a unique risk classification for our largely Chinese population. 2) Assess extent of thyroid surgery required. 3) Document prognostic value of UICC and AMES classification.
Methods Retrospective review of 175 patients treated for primary thyroid epithelial malignancy by the Department of General Surgery at the Singapore General Hospital.
Results There were 78% papillary carcinomas (PC) and 19% follicular carcinomas (FC). Female: male ratio was 3:1. Patient distribution in the UICC stages I, II, III, IV is respectively 56, 11, 31 and 2%. Twenty-six percent had hemithyroidectomy, and 74% total thyroidectomy. Neck dissections were required in 6% of FC compared to 34% of PC. Mean follow-up was 40 months. Extent of surgery did not affect PC/FC survival nor recurrence rates (p=0.53 and 0.06 respectively). Recurrences occurred in 15% FC and 9% PC. Death occurred in one FC and two PC. Survival correlated with UICC stage I/II and stage III/IV groups (p=0.04), and recurrence correlated with AMES High and Low Risk groups (p=0.004). No statistically significant difference was shown for survival between PC and FC or AMES groups and recurrence between PC and FC or UICC groups.
Conclusion Extent of thyroid surgery does not significantly affect local recurrences of PC/FC. The characterisation of thyroid carcinoma here is an important step towards developing a risk classification unique to our largely Chinese population.

Keywords: Thyroid carcinoma, Chinese, risk-group classification, extent surgery
Singapore Med J 2002; 43(9): 457-462

SP Ho, TH Ho
Correspondence: Dr Ho Sio Ping, kho@pacific.net.sg

ABSTRACT
Objectives To review the clinico-pathological features of malignant mixed Mullerian tumours of the uterine corpus, their prognosis and treatment outcome.
Methods A retrospective study of malignant mixed Mullerian tumours of the uterus seen at KK Women's & Children's Hospital from January 1989 to December 1998.
Results and Conclusion Twenty-six patients with mean age of 56.5 years were analysed. Twenty (76.9%) were menopausal. None had previous pelvic irradiation. Vaginal bleeding and uterine enlargement were the commonest presenting symptom and sign. Diagnostic dilatation and curettage obtained the diagnosis in 15 patients. Majority of patients had surgery with adjuvant chemotherapy, while adjuvant radiotherapy was offered only recently. Positive peritoneal washings were significantly associated with advanced disease. There were seven patients with stage I, four with stage II, nine with stage III and four with stage IV disease. There were 17 homologous and nine heterologous tumours. Presence of heterologous stromal components did not influence the stage of the disease. Increasing depth of myometrial invasion was associated with poorer survival. Prognosis of patients with stage III and IV disease were poor, with none surviving to two years. All the patients with stage I disease were still alive at the end of the study period. In conclusion, malignant mixed Mullerian tumours of the uterine corpus are aggressive tumours associated with poor prognosis.

Keywords: malignant mixed Mullerian tumours
Singapore Med J 2002; 43(9): 452-456

H-K Goh, EJC Lee
Correspondence: Dr Evan J C Lee, leejc@nuh.com.sg

ABSTRACT
The profile of admissions to an acute dialysis care facility of the National University Hospital Renal Centre, Singapore was studied in an attempt to identify the needs of these patients so that admissions may be possibly reduced. All patients above the age of 18 years who were admitted to the dialysis centre in the National University Hospital for dialysis between 1 Jan 2000 and 31 Mar 2000 inclusive were studied. A total of 124 patients were studied. Almost all the patients had end stage renal failure. The commonest cause of end stage renal failure was diabetic nephropathy (58.8%). There were a total of 157 admissions. Most of the admissions were associated with end stage renal failure (96%). Vascular access problems caused 40% of all admissions and 68% of all multiple admissions. The data suggest that a dialysis facility in a multidisciplinary acute hospital needs to meet the requirements of mainly patients who are already in end stage renal failure, those who have vascular access problems and those who have diabetes.

Keywords: end stage renal failure, diabetes mellitus, dialysis, vascular access, Singapore
Singapore Med J 2002; 43(9): 447-451

YC Yee, A Gough, G Kumarasinghe, TK Lim
Correspondence: Dr T K Lim, mdclimtk@nus.edu.sg

ABSTRACT
Background Several nucleic acid amplification (NAA) tests are available for the rapid detection of Mycobacterium tuberculosis (MTB) in clinical specimens.
Aims To identify the pattern of utilisation and accuracy of the AMPLICOR test in routine clinical practice in an acute care setting.
Design A retrospective descriptive study.
Method We studied 159 consecutive specimens in which the AMPLICOR (Roche; Branchburg, NJ) test was requested by attending doctors. The sensitivities and specificities of the AMPLICOR for detection of active tuberculosis (TB) were calculated in relation to types of specimens, smear and culture results.
Results The number of requests more than doubled from 1999 to 2000. Thirty-eight percent of the specimens were not from the respiratory tract. The majority of the specimens had requests for one or more additional test (mean 1.8). The rate of active TB was 18%. The sensitivities of the AMPLICOR on per specimen, per patient, per smear negative specimen and per smear negative patient basis were found to be 81%, 80%, 66.7% and 71.4% respectively. The specificities for these groups accordingly were 99%, 98.6%, 99% and 98.6% respectively. The sensitivity and specificity for respiratory specimens were 97.5% and 98.5%, while for non-respiratory specimens, they were 60% and 100%. In smear negative specimens, the sensitivity and specificity for respiratory specimens were 60% and 98.5%, while for non-respiratory specimens, they were 75% and 100%. The AMPLICOR assay was negative in all 21 specimens of pleural or spinal fluid.
Conclusion There is a growing demand for NAA in the rapid diagnosis of TB with a high proportion of non-respiratory specimens. The number of additional diagnostic tests performed on each specimen should be limited. In routine clinical practice, the AMPLICOR assay is a useful confirmatory test for active pulmonary TB. The utility of the AMPLICOR assay for MTB detection in exudative fluid specimens needs further evaluation.

Keywords: nucleic acid amplification, tuberculosis, sensitivity
Singapore Med J 2002; 43(8): 415-420

TS Chua, KM Fock, EK Teo, TM Ng
Correspondence: Dr Chua Tju Siang, Tju_Siang_Chua@cgh.com.sg

ABSTRACT
Introduction Several tests are available for determining the presence of Helicobacter pylori (H. pylori) infection. These may be invasive or non-invasive. The carbon urea breath test (C-UBT) is generally considered to be a simple, non-invasive and accurate test for the detection of H. pylori infection both before and after treatment. Commercially available 13C-UBT kits are generally validated in their country of manufacture and the stated accuracy of their tests may not be applicable to our local population.
Aim The aim of our study was to determine the accuracy of a commercial 13C-urea breath test kit, Hp-Plus (Utandningstester i Sverige AB, Sweden), in the Singapore population.
Patients and Methods One hundred patients for oesophago-gastro-duodenoscopy (OGD) were recruited into this prospective study. Gastric biopsies were obtained for the biopsy urease test and histological examination. Blood samples were obtained for H. pylori serology. Breath samples were then obtained at baseline and after consumption of 100 mg of labelled 13C-urea. The presence of H. pylori infection was defined by a positive result on any two of the three tests (biopsy urease test, histology, serology) performed for the detection of H. pylori. Using this "gold standard", the sensitivity, specificity, and positive and negative predictive values of the 13C-UBT were calculated.
Results In the Singapore population, the 13C-UBT (Hp plus) has a sensitivity and specificity of 94.2% and 100% respectively for the detection of H. pylori infection. The positive predictive value and negative predictive value of the 13C-UBT is 100% and 88.6% respectively.
Conclusion The 13C-UBT is a simple, safe, and accurate non-invasive test for the detection of H. pylori infection, making it a valuable tool in local clinical practice.

Keywords: Helicobacter pylori, urea breath test
Singapore Med J 2002; 43(8): 408-411