BRIrNm 19that might prove advantageous is the substitution of 5 % dextrose for 0.9 % saline in those patients who are initially hypernatraemic.The values for salicylate clearance given in Table II and Fig. 2 cannot be compared with those of other authors as they are based on total serum salicylate concentrations-as measured by the method of Trinder (1954)-and not on the unbound fraction only. They are presented, nevertheless, because they provide the clinician with a rough estimate of the rate of salicylate excretion that he may obtain with acetazolamide and sodium bicarbonate infusion at any given serum salicylate level. In Fig. 2 creatinine clearance values are also shown, since the glomerular filtration rate is sometimes low in salicylate overdosage and may be further depressed by acetazolamide (Milne, 1963). The effectiveness of the treatment regimen might be limited by this, and also by competition for tubular secretion between acetazolamide and salicylate (Weiner et al., 1959).Although this paper lays greater emphasis on a very high urine pH than a very high urine flow, it is clear that the rate of flow must still be a factor limiting salicylate clearance. When rehydration is not promptly followed by a brisk diuresis the use of an osmotic diuretic may therefore still be of value. We have unpublished data to show that the addition of mannitol to the present treatment regimen can further increase salicylate clearance. It should, however, be borne in mind that mannitol may cause complications of its own (Morgan et al., 1968).It is not suggested that acetazolamide and sodium bicarbonate treatment will replace haemodialysis in the severest cases of salicylate intoxication, for in these there may be other indications for dialysis than the serum salicylate concentration. However, the concentration itself may often be brought down to a safer level during the time required to transfer a patient to a dialysis unit. We have recently treated two such patients prior to dialysis, reducing the serum salicylate in one from 136 to 107 mg./100 ml. in two hours, and in the other from 104 to 69 mg./100 ml. in three hours.

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