Ann Acad Med Singap
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Malignant hyperthermia (MH) is a pharmacogenetic disorder of skeletal muscle. In humans, MH is inherited in an autosomal dominant fashion; in swine, the principal model for MH, it is in a recessive fashion. Those with MH susceptibility usually are asymptomatic except in the presence of certain "triggering" anaesthetic agents such as isoflurane, enflurane and the muscle relaxant succinylcholine. ⋯ The pathophysiology of MH centres around a defect in calcium flux in skeletal muscle. A specific base pair change in the gene that codes for the ryanodine receptor calcium channel in muscle has been demonstrated in susceptible swine, but occurs rarely in humans. It is hoped that the understanding of the molecular genetics of MH will lead to a simpler diagnostic test than is currently available, and enhance our understanding of MH and its relation to other myopathies.
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Ann Acad Med Singap · Nov 1994
Case ReportsHigh resolution computed tomography of the temporal bone: preliminary experience.
High Resolution Computed Tomography (HRCT) can demonstrate the detailed anatomy and pathology of the temporal bone and is fast becoming an important imaging modality in the diagnosis and preoperative management of our local patients with temporal bone diseases. We present our experience in the usage of HRCT in temporal bone lesions in Tan Tock Seng Hospital, using 8 cases as illustration. ⋯ We also give an overview of those clinical conditions whereby HRCT can provide information which will help surgeons in the management of their patients. These clinical conditions are hearing loss, external auditory canal atresia, middle ear inflammation/cholesteatoma, temporal bone trauma, pulsatile tinnitus and vascular tympanic membrane.
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Ann Acad Med Singap · Nov 1994
Physiologic chart for rapid identification of causes of abnormal haemodynamics.
The systemic haemodynamic state is expressed by paired values of Mean Arterial Pressure (MAP) and Stroke Index (SI), varying for every heart beat. Algebraic product of SI and Heart Rate (HR) then defines the perfusion-related Cardiac Index (CI), which is the dynamic modulator of Oxygen Delivery Index (DO2I). Since MAP, SI and CI can each attain a normal, infranormal or supranormal level, there is a total of 9 haemodynamic states, plus 3 CI states. ⋯ The deviation in CI from its normal level then determines the deviation in chronotropy. In contrast to current management methodology of trial and error, the HMC enables the clinician to continuously manage a patient's haemodynamics within the HTG. This is expected to produce a shorter therapy and improved outcome.
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Formal Quality Assurance programmes have been widely promoted and applied in anaesthesia departments in the United States of America. The rationale of three well-known programmes is examined. Although they may be of use as a method of examining one's own practice, there is little objective evidence to support the idea of measuring an anaesthesiologist's competence. There is also a danger that licensing authorities will misuse such spurious information.
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Although epidural and spinal blocks are well-accepted regional techniques in obstetrics, they have several disadvantages. Combined spinal-epidural (CSE) technique reduces or eliminates the risks of these disadvantages. The sequential CSE technique can reduce the incidence and severity of maternal hypotension. ⋯ Before any injection in the epidural catheter, its position should always be confirmed by aspiration test. The technique should be used only by those who are experienced in spinal and epidural blocks. CSE is an important addition to the armamentarium of the obstetric anaesthesiologist.