Difficult Extubation: Calming the Sympathetic Storm

Tracheal extubation can evoke an equally strong haemodyamic stress response as tracheal intubation. We present a patient with myocardial infarction who repeatedly failed tracheal extubation. He developed acute pulmonary oedema following each attempt at tracheal extubation due to sympathetic overactivity. A change of approach with extubation under propofol sedation followed by continued sympatholysis with dexmedetomidine infusion allowed successful extubation.

Use of recombinant factor VIIa to treat life-threatening non-surgical bleeding in a post-partum patient

Ongoing bleeding from patients who have an acquired coagulopathy post-surgery is a common problem. Strategies that are available to combat this problem revolve around the replacement of coagulation factors, platelets, and red blood cells as necessary. These strategies are not always successful and a more direct approach to activating the coagulation system can be more effective and in some instances life saving. We describe the use of recombinant factor VIIa in a patient with ongoing post partum bleeding.

Management of bee-sting anaphylaxis

A retrospective case analysis of 101 adverse reactions to bee-stings and a prospective questionnaire analysis of the proposed management by local medical practitioners and resident hospital staff members of three hypothetical bee-sting reactions has revealed that understanding of the use of adrenaline in patients with reactions to bee envenomation is confused with regard to the indications for its use, dosage and route; that corticosteroid agents are used or are recommended too frequently, sometimes as the sole therapeutic agent; and that there is a lack of awareness of the need for volume replacement in hypotensive shocked patients. These conclusions highlight the urgent need for a greater understanding of the optimal forms of management for patients with acute anaphylactic reactions to bee envenomation.

Anaesthesia and the kidney

Applied anatomy and physiology of the kidney are briefly reviewed. This includes an account of renal blood flow, glomerular filtration rate, juxtaglomerular apparatus, renal autoregulation and intra-renal blood flow distribution, tubular transport mechanisms, solute handling in proximal tubule, function of loop of Henle and distal tubule system. This section concludes with a summary of changes in tubule fluid along the length of the nephron. Acute effects of anaesthesia are reviewed in detail. Indirect effects include those on circulatory and sympathetic nervous systems, autoregulation, endocrine systems such as those involving anti-diuretic hormone, adrenaline and noradrenaline, renin-angiotensin and aldosterone. Direct effects of anaesthesia on renal function have now been confirmed both in vitro and in vivo. Delayed direct nephrotoxicity of anaesthetics relates predominantly to methoxyflurane (MOF) and its metabolism to inorganic fluoride. Other factors are MOF dose, genetics, age, enzyme induction, obesity, other nephrotoxic drugs. Clinical implications are presented. Enflurane nephrotoxicity is rare but aetiologic factors are similar to the foregoing. Isoflurane and halothane are not nephrotoxic. A consideration of the influence of anaesthetic management on the incidence and severity of postoperative acute renal failure concludes the review.