Ann Acad Med Singap
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The immune system is a powerful, complex entity composed of numerous cell types and regulated by autocrine, paracrine, and hormonal mechanisms. Trauma and haemorrhagic shock induce numerous changes within this system which are ultimately deleterious and contribute to the high incidence of organ dysfunction and infectious complications seen following injury. Regional hypoxia and depletion of intracellular energy stores occur in response to diminished microcirculatory blood flow, and these changes alter cellular signalling and result in the release of pro-inflammatory cytokines and prostanoids which mediate further suppression of immune function. ⋯ The resulting depression in cell mediated and humoral immunity renders the organism susceptible to microbial infection and contributes to the morbidity and mortality associated with nosocomial infections. Hormonal modulation of the immune response is highly evident following trauma and haemorrhage, and the preponderance of male morbidity associated with sepsis can be explained by the depression in immune function seen in males, but not females in the pro-oestrous state. Despite the multitude of changes induced by trauma and haemorrhage, experimental studies have revealed several promising pharmacologic interventions which may serve to blunt the effect of injury on the immune system, and render the host competent to withstand the bacterial and viral challenges responsible for so much of the late mortality following severe injury.
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Ann Acad Med Singap · Jan 1999
Efficacy of contraction uncoupling by 2,3-butanedione monoxime during initial reperfusion versus cardioplegic arrest for protection of isolated hearts.
The efficacy of 2,3-butanedione monoxime (BDM) as additive to St. Thomas Hospital II solution (STH) as compared to initial BDM reperfusion with regard to myocardial ischaemia/reperfusion injury was investigated in isolated guinea pig hearts. Isolated guinea pig hearts were perfused with Krebs-Henseleit buffer in the Langendorff technique at constant pressure of 55 mmHg. ⋯ Addition of BDM to the cardioplegic STH solution did not protect isolated hearts from cellular injury or depression of post-ischaemic function. In contrast, initial BDM reperfusion alone attenuated reperfusion contracture, prevented LDH release, and improved recovery of systolic and diastolic myocardial function. The combination of BDM treatment during cardioplegic arrest with initial BDM reperfusion provides no additional protection from reperfusion injury.
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Ann Acad Med Singap · Nov 1998
Risk factors for predicting mortality in a paediatric intensive care unit.
Rapid advances in critical care technology and rising cost of medical care have spurred the development of outcome analysis including mortality risk prediction. The main objective of this study was to assess the risk factors contributing to mortality in our paediatric intensive care unit (PICU). This is a cohort study, consisting of consecutive admissions to the PICU from 1 January to 31 December 1997. ⋯ Univariate analysis showed that need for mechanical ventilation, renal replacement therapy, presence of MODS involving 3 or more organs and PRISM III-24 scores were significantly associated with outcome (P < 0.0005). Relative risk of mortality in the presence of MODS and PRISM III-24 scores > or = 8 were 11.3 (95% CI: 3.3 to 38.3) and 15.8 (95% CI: 2.0 to 127.8), respectively. Using Cox Proportional Hazards model, the relative risk of mortality for any new admission could be calculated by the equation RR = e0.1032 x P, where P = PRISM III-24 scores.
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Ann Acad Med Singap · Nov 1998
Computed tomographic and magnetic resonance imaging findings in paranasal sinus involvement in nasopharyngeal carcinoma.
Nasopharyngeal carcinoma (NPC) may spread to the paranasal sinuses. This retrospective study describes the features of paranasal sinus involvement in NPC on computed tomography (CT) and magnetic resonance imaging (MRI). One hundred and fourteen patients with histologically proven NPC underwent staging with both CT and MRI. ⋯ Using MRI as the standard, the rates of CT separating tumour from inflammation are: maxillary sinus (100%), sphenoid sinus (43%) and ethmoid sinus (25%). Histological confirmation of tumour involvement in the paranasal sinuses is not available. It is important to separate sinusitis from tumour infiltration as prognosis and treatment planning may be affected.
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Ann Acad Med Singap · Nov 1998
Is it feasible to use magnesium sulphate as a hypotensive agent in oral and maxillofacial surgery?
We report the results of a feasibility study using intravenous magnesium sulphate for deliberate hypotension in 16 ASA 1 patients undergoing major oral and maxillofacial surgery. All the patients received a standard nitrous oxide, oxygen, isoflurane, opioid and muscle relaxant anaesthetic. Magnesium sulphate was infused at 40 g/h until the mean arterial pressure reached 55 +/- 5 mmHg, followed by a maintenance dose of 5 g/h until 30 minutes prior to the end of surgery. ⋯ On completion of surgery, the prothrombin time was significantly increased (P < 0.05), and the partial thromboplastin time significantly decreased (P < 0.05) in all the patients (when compared to preoperative values); the clinical significance of this is unclear. The use of intravenous magnesium sulphate for deliberate hypotension is feasible in ASA 1 patients using a standard nitrous oxide, oxygen, isoflurane, opioid and muscle relaxant technique. This study forms the basis for a larger controlled study where the issues of postoperative sedation and weakness and coagulopathy can be dealt with in greater detail.