Best practice & research. Clinical anaesthesiology
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Best Pract Res Clin Anaesthesiol · Mar 2004
ReviewAcid-base balance in acute renal failure and renal replacement therapy.
The approach to acid-base balance based on the concept of strong ions, initially proposed by Stewart, is briefly overviewed. The anion gap and the strong anion gap are both discussed. ⋯ The consequences of renal metabolic acidosis are described. Finally, the impact of renal replacement therapy on acid-base balance is exposed; different modalities of renal replacement are considered in regard to their alkalinizing performance.
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Malignant hyperthermia (MH) is an uncommon, life-threatening, acute pharmacogenetic disorder of the skeletal muscle cell. It manifests in susceptible individuals as a hypermetabolic response on exposure to halogenated volatile anaesthetics and depolarizing muscle relaxants. There may also be a relationship between susceptibility to MH, heat stroke and exercise-induced rhabdomyolysis. ⋯ Immediate discontinuation of triggering agents, oxygenation, and correction of acidosis and electrolyte abnormalities, cooling and dantrolene are essential for treatment of the syndrome. Thanks to clinical and research investigations, widespread education and the introduction of dantrolene sodium, the mortality from MH is less than 5%. This chapter provides an overview and an update of MH.
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Best Pract Res Clin Anaesthesiol · Dec 2003
ReviewPerioperative hypothermia in the high-risk surgical patient.
Perioperative hypothermia is common in high-risk surgical patients. Anaesthesia impairs central thermoregulation, allowing re-distribution of body heat. Cool ambient temperatures and high-volume fluid administration accelerate loss of heat to the environment. ⋯ The most effective means of preventing perioperative hypothermia is active pre-warming. High ambient temperatures, warmed intravenous fluids and active cutaneous warming are useful intra-operatively, while active cutaneous warming and intravenous pethidine abolish post-operative shivering. Proper thermal management may reduce complications and improve the outcome in high-risk surgical patients.
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Anaesthesia alters normal thermoregulatory control of the body, usually leading to perioperative hypothermia. Hypothermia is associated with a large number of serious complications. To assess perianaesthetic hypothermia, core temperature should be monitored vigorously. ⋯ Intravenous fluid warming is also helpful when large volumes are required. In some patients, induction of mild therapeutic hypothermia may become an issue for the future. Recent studies indicate that patients suffering from neurological disease may profit from rapid core cooling.
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Hypothermia is common during anaesthesia and surgery owing to anaesthetic-induced inhibition of thermoregulatory control. Perioperative hypothermia is associated with numerous complications. However, for certain patient populations, and under specific clinical conditions, hypothermia can provide substantial benefits. ⋯ Mild hypothermia has been shown to improve outcome after cardiac arrest in humans. Randomized trials are in progress to evaluate the potential benefits of mild hypothermia during aneurysm clipping and after stroke or acute myocardial infraction. However, as hypothermia can cause unwanted side-effects, further research is needed to better quantify the risks and benefits of therapeutic hypothermia.