MyMedR

A novel method of deriving the effect compartment equilibrium rate constant for propofol

Lim TA

Br J Anaesth, 2003 Nov;91(5):730-2.

BACKGROUND: Calculation of the effect compartment concentration (Ce) in non-steady-state conditions requires the equilibrium rate constant, keo. Most studies of propofol derive the keo using EEG measurements. This study investigated an alternative method. Starting from a predicted concentration-time profile, a keo value was included so that the predicted Ce at a specific pharmacodynamic end-point was the same when using three different methods of injection.

METHODS: Seventy-five patients were given propofol for induction of anaesthesia. Twenty-five patients received a single bolus, 25 patients received an infusion, and 25 patients received a bolus followed by an infusion. Computer simulation was used to derive the central compartment concentration. The keo that brought about the same value for Ce at loss of the eyelash reflex using the three methods of injection was derived.

RESULTS: Keo was found to be 0.80 min(-1). Mean (SD) Ce at loss of the eyelash reflex was 2.27 (0.69) microg ml(-1).

CONCLUSIONS: The effect compartment equilibrium rate constant and concentration at loss of the eyelash reflex can be derived without the use of electronic central nervous system monitors.

Predicted effect compartment concentration of thiopental at loss of eyelash reflex

Lim TA, Inbasegaran K

Br J Anaesth, 2001 Mar;86(3):422-4.

PMID: 11573534

We derived the predicted effect compartment concentration of thiopental, at loss of the eyelash reflex, following three different injection regimens. Sixty patients were given thiopental for induction of anaesthesia. Twenty patients received multiple small boluses, 20 patients received a single bolus and 20 patients received an infusion. Computer simulation was then used to derive the effect compartment concentration. The median concentration was not significantly different between the three groups. EC50, derived after combining all three groups was 11.3 microg ml(-1). The EC05-EC95 range was 6.9-18.3 microg ml(-1), suggesting wide inter-individual variation.

Fulltext Factors influencing post-operative hyperglycaemia in type 2 diabetes mellitus patients managed without intra-operative insulin

Tan BL, Lim TA

Med J Malaysia, 2006 Mar;61(1):122-4.

PMID: 16708751

Surgery induces a 'stress' state leading to post-operative hyperglycaemia. To investigate this effect on patients with Type 2 Diabetes Mellitus, we reviewed the records of 50 diabetic patients who underwent surgery without intraoperative insulin. Demographic features together with pre-operative and post-operative blood glucose readings were noted. 27.3% of patients with well controlled pre-operative blood glucose levels developed post-operative hyperglycaemia. In contrast, 84.6% of patients with poorly controlled levels developed the same. Poor control of blood glucose and duration of operation were the only significant predictors of post-operative hyperglycaemia.

Fulltext Pre-operative investigations: yield and conformity to national guidelines

Juliana H, Lim TA, Inbasegaran K

Med J Malaysia, 2003 Mar;58(1):5-16.

PMID: 14556321

Routine ordering of pre-operative investigations yields a low true positive rate and is not cost effective. In this study, case notes of 251 adults who underwent elective surgery were reviewed. Pre-operative investigations were classified as 'indicated' or 'not indicated', based on the national guidelines. Only 56% of all tests done were indicated. The overall rates of expected and unexpected abnormal values from pre-operative blood investigations were 51.1% and 34.4% respectively. This study found that selective testing based on guidelines was beneficial. However, the results also suggest that the local guidelines need to be reviewed.

Fulltext Peri-operative blood pressure changes in normotensive and hypertensive patients

Poh KS, Lim TA, Airini IN

Med J Malaysia, 2007 Jun;62(2):97-103.

PMID: 18705438

Controversy surrounds the acceptance of hypertension as an independent risk factor for anaesthesia. In an attempt to identify variables that are associated with increased haemodynamic instability during surgery, the blood pressure profiles of 128 patients were analysed. The two variables that contributed most to the instability were pre-operative control of blood pressure and anaesthetic technique. To reduce the fluctuation in blood pressure, it is advisable for patients to be given a regional anaesthetic. Current therapy for hypertension appears to exaggerate the depressant effects of anaesthetic drugs. Care must be taken not only to prevent hypertensive episodes during surgery, but also hypotension.

Fulltext Anaesthesia for a patient with long QT syndrome undergoing renal transplantation

Lim KY, Lim TA, Wong WH

Med J Malaysia, 2005 Dec;60(5):647-9.

PMID: 16515119

Anaesthetizing patients with Long QT Syndrome is a major challenge, as the potential for sudden catastrophic cardiovascular collapse is well known. We present a 15-year-old boy with Long QT Syndrome who presented for an elective renal transplant. All electrolyte concentration abnormalities were corrected preoperative and adequate beta-blockade was maintained. The patient was given a target controlled infusion of propofol, together with opioids and atracurium. Anaesthesia was uneventful and the patient was extubated at the end of the surgical procedure.

Effect-compartment equilibrium rate constant (keo) for propofol during induction of anesthesia with a target-controlled infusion device

Lim TA, Wong WH, Lim KY

J Anesth, 2006;20(2):153-5.

PMID: 16633780

The effect-compartment concentration (C(e)) of a drug at a specific pharmacodynamic endpoint should be independent of the rate of drug injection. We used this assumption to derive an effect-compartment equilibrium rate constant (k(eo)) for propofol during induction of anesthesia, using a target controlled infusion device (Diprifusor). Eighteen unpremedicated patients were induced with a target blood propofol concentration of 5 microg x ml(-1) (group 1), while another 18 were induced with a target concentration of 6 microg x ml(-1) (group 2). The time at loss of the eyelash reflex was recorded. Computer simulation was used to derive the rate constant (k(eo)) that resulted in the mean C(e) at loss of the eyelash reflex in group 1 being equal to that in group 2. Using this population technique, we found the k(eo) to be 0.57 min(-1). The mean (SD) effect compartment concentration at loss of the eyelash reflex was 2.39 (0.70) microg x ml(-1). This means that to achieve a desired C(e) within 3 min of induction, the initial target blood concentration should be set at 1.67 times that of the desired C(e) for 1 min, after which it should revert to the desired concentration.

Fulltext Perceived skill and utilisation of information technology in medical education among final year medical students, Universiti Putra Malaysia

Lim TA, Wong WH, Lim KY

Med J Malaysia, 2005 Oct;60(4):432-40.

PMID: 16570704

The objective of this survey was to obtain a self-reported assessment of the use of information technology (IT) by final year medical students. Two hundred and sixty five students responded to a questionnaire survey. 81.5% of students considered their computer skills adequate, while 87.9% had access to computers outside the campus. Most students reported adequate skills at word processing, e-mailing and surfing the Internet. Fifty three percent of students spent three hours or more each week on the computer. While students indicated a general willingness to access Internet-based materials, further steps need to be taken to increase the use of this method of instruction.

Fulltext A review of the acute pain service in Hospital Kuala Lumpur

Neelima G, Chieng DC, Lim TA, Inbasegaran K

Med J Malaysia, 2003 Jun;58(2):167-79.

PMID: 14569736 MyJurnal

This study is a review of the Acute Pain Service in Hospital Kuala Lumpur for the years 1998 to 2001. 5042 records from post-operative patients were analysed. The majority of patients (81.8%) had satisfactory pain control. Eighty-two percent of patients experienced only mild pain at rest on the first post-operative day. The highest pain score occurred on the first day in 68.3% of patients. Nausea or vomiting occurred in 23.2% of the patients. Eight patients had respiratory depression. The low pain scores recorded by most patients and the low incidence of side effects reflect the efficiency of the service provided.

The association between physical activity and burnout among anaesthesia postgraduate trainees in Malaysia

Jaishree S, Chong KW, Lim TA

Med J Malaysia, 2022 Nov;77(6):655-660.

PMID: 36448381

INTRODUCTION: Burnout is a psychological problem which is becoming more prevalent among medical professionals resulting in various negative outcomes. Physical activity has been found to be an effective method in alleviating burnout. The aim of this study was to determine the association between physical activity and burnout among postgraduate anaesthesia trainees in Malaysia. The study also intended to determine the level of physical activity among trainees, the factors affecting this practice, and the prevalence of burnout among anaesthesia trainees.

MATERIALS AND METHODS: An online self-administered questionnaire was sent out to all postgraduate anaesthesia trainees between August 2020 and January 2021 via email and respondents were recruited on a voluntary basis.

RESULTS: The prevalence of burnout among postgraduate anaesthesia trainees was high (54%). This prevalence was higher among trainees with low a level of physical activity. Half of the trainees (50.8%) engaged in moderate physical activity while only 12% reported a high level of physical activity. The postgraduate study year was found to be a significant factor affecting the practice of physical activity.

CONCLUSION: There is a significant association between physical activity and burnout among postgraduate anaesthesia trainees in Malaysia. Physical activity has the potential to be an essential method of reducing burnout. Hence, measures should be implemented to improve the practice of physical activity among healthcare professionals in order to reduce workplace burnout.

Automation of anaesthesia: a review on multivariable control

Chang JJ, Syafiie S, Kamil R, Lim TA

J Clin Monit Comput, 2015 Apr;29(2):231-9.

PMID: 24961365 DOI: 10.1007/s10877-014-9590-6

Anaesthesia is a multivariable problem where a combination of drugs are used to induce desired hypnotic, analgesia and immobility states. The automation of anaesthesia may improve the safety and cost-effectiveness of anaesthesia. However, the realization of a safe and reliable multivariable closed-loop control of anaesthesia is yet to be achieved due to a manifold of challenges. In this paper, several significant challenges in automation of anaesthesia are discussed, namely model uncertainty, controlled variables, closed-loop application and dependability. The increasingly reliable measurement device, robust and adaptive controller, and better fault tolerance strategy are paving the way for automation of anaesthesia.

Utilization of information technology in medical education: a questionnaire survey of students in a Malaysian institution

Nurjahan MI, Lim TA, Yeong SW, Foong AL, Ware J

Med J Malaysia, 2002 Dec;57 Suppl E:58-66.

PMID: 12733195

OBJECTIVE: The objective of this survey was to obtain a self-reported assessment of the use of Information and Communication Technology (ICT) by medical students at the International Medical University, Malaysia.
MATERIALS AND METHODS: Students' perceived skills and extent of usage of ICT were evaluated using a questionnaire. Chi-square analysis were performed to ascertain the association between variables. Further statistical testing using Chi-square test for trend was done when one of the variables was ordered, and Spearman rank correlation when both variables were ordered.
RESULTS: Overall, (98%) of students responded to the questionnaire. Twenty seven students (5.7%) did not use a computer either in the university or at home. Most students surveyed reported adequate skills at word processing (55%), e-mailing (78%) and surfing the internet (67%).
CONCLUSION: The results suggests that in order to increase the level of computer literacy among medical students, positive steps would need to be taken, for example the formal inclusion of ICT instruction in the teaching of undergraduate medicine. This will enhance medical students' ability to acquire, appraise, and use information in order to solve clinical and other problems quickly and efficiently in the course of their studies, and more importantly when they graduate.

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