Cerebral arteriovenous malformations in children

The treatment of cerebral arteriovenous malformations (AVM) or vascular anomalies are challenging neurosurgical procedures for an anaesthetist. Large AVMs are uncommon in children. Only 18% of AVMs become symptomatic before the age of 15 yr. This series reviews the experience at this institution during the period of 1982 to 1992. The symptoms at the time of presentation are varied and include haemorrhage (50%), seizures and hydrocephalus (36%) or congestive cardiac failure (18%). Symptoms of congestive heart failure predominate in the new-born whilst neurological symptoms, such as stroke, seizures or hydrocephalus occur more commonly in infants and older children. Approximately one third of AVMs in childhood present acutely. Radiological investigations, e.g., CT scan, MRI and cerebral angiography are essential to identify the precise location of the lesion. Therapeutic intervention in the acute presentation may involve craniotomy for evacuation of haematoma and treatment of increased intracranial pressure (ICP). Control of seizures and congestive heart failure may take priority and allow time to plan the elective procedures of embolization and surgical excision of the AVM. Operative intervention is hazardous and peroperative complications can be expected in more than 50% of patients. The morbidity and mortality associated with cerebral AVM are high, especially in infants who present in the neonatal period with congestive cardiac failure. The overall mortality in this series was 20%. Children presenting with intracranial arteriovenous malformations require a multidisciplinary approach. The successful management of anaesthesia either for embolization or surgical resection necessitates an understanding of the disciplines of paediatric and neuroanaesthesia. Special care and specific attention to detail may contribute to reduce the high morbidity and mortality encountered in these compromised children.     

Is residual impairment after alcohol an effect of repeated performance?

BACKGROUND: The study examines the residual impairment of performance due to alcohol on the descending limb of the blood alcohol curve. The occurrence of residual impairment at low or zero levels of blood alcohol is well established but its cause is uncertain. It is hypothesized that residual impairment may be due in part to the methodological procedure of repeated performance testing in the post-ingestion period. METHODS: There were 80 volunteers randomly allocated to one of four treatment conditions: a) alcohol and repeated performance (A-R) where psychomotor tasks were performed at 20-min interval for 2 h post ingestion; b) alcohol and double performance (A-D) where tasks were performed only at 1 h and 2 h from ingestion; c) placebo and repeated performance (P-R); and d) placebo and double performance (P-D). Alcohol was administered as vodka to achieve a peak blood-alcohol concentration (BAC) of approximately 80 mg per 100 ml. Performance effects were assessed by a dual task of primary pursuit tracking and secondary visual reaction time, and a visual sustained attention task. RESULTS: Alcohol caused significant impairment of secondary reaction time, the effect being greatest at peak BAC. Sustained attention was also impaired by alcohol but the effect just missed significance. Repeated performance conditions were associated with significantly greater impairment of secondary reaction time and sustained attention when compared with double performance conditions. The factor of performance condition did not, however, interact with that of alcohol. CONCLUSIONS: The monotony and boredom that may be associated with repeated performance do not contribute to residual alcohol impairment.     

Antioxidant effects of aminosalicylates and potential new drugs for inflammatory bowel disease: assessment in cell-free systems and inflamed human colorectal biopsies

BACKGROUND: The therapeutic efficacy of 5-aminosalicylic acid in inflammatory bowel disease may be related to its antioxidant properties. AIM: To compare in vitro the antioxidant effects of conventional drugs (5-aminosalicylic acid, corticosteroids, metronidazole), with new aminosalicylates (4-aminosalicylic acid, balsalazide) and other potential therapies (ascorbate, N-acetylcysteine, glutathione, verapamil). METHODS: Compounds were assessed for efficacy in reducing the in vitro production of reactive oxygen species by cell-free systems (using xanthine/xanthine oxidase, with or without myeloperoxidase) and by colorectal biopsies from patients with ulcerative colitis using luminol-amplified chemiluminescence. RESULTS: 5-aminosalicylic acid and balsalazide were more potent antioxidants than 4-aminosalicylic acid or N-acetyl-5-aminosalicylic acid in cell-free systems. 5-aminosalicylic acid (20 mM) and balsalazide (20 mM) inhibited rectal biopsy chemiluminescence by 93% and 100%, respectively, compared with only 59% inhibition by 4-aminosalicylic acid (20 mM). Hydrocortisone, metronidazole and verapamil had no significant effect on chemiluminescence in any system. Ascorbate (20 mM) inhibited chemiluminescence by 100% in cell-free systems and by 60% in rectal biopsies. N-acetyl cysteine (10 mM), and both oxidized and reduced glutathione (10 mM), completely inhibited chemiluminescence in cell-free systems, but not with rectal biopsies. CONCLUSIONS: The antioxidant effects of compounds varies between cell-free systems and inflamed colorectal biopsies. The effect of drugs on the chemiluminescence produced by these two assay systems is useful for screening potentially new antioxidant treatments for inflammatory bowel disease. Ascorbate seems worth further study as a novel therapy.