Szemészet, 1975 (112. évfolyam, 1-3. szám)
1975 / 3. szám
Procedure: 5000 ml of bidistilled water are poured into a 20 000 ml container, saturated with nitrogen and 475 g of sodium bicarbonate are then added and dissolved. Under the nitrogen flow, the solution is stirred for some minutes. Then, the nitrogen flow is stopped and, gradually, 1000 gs of ascorbic acid are added to the alkaline solution. At this moment, it is necessary to proceed carefully as there is a considerable development of carbon dioxide and the solution becomes fairly cold. When the ascorbic acid is completely dissolved, more distilled water is added until there is no more undissolved substance, whilst the solution is being continuously agitated and brought to room temperature by heating. The solution, whose pH measures now approximately 6,5, is maintained under vacuum for about 30 minutes in order to eliminate the residual carbon dioxide and then saturated with nitrogen. Thyoglycerol (20 grams) and Phenol (5 grams) are now dissolved. Pure glycerol (1000 grams) is furthermore added. With 2% sodium hydrate, which has been prepared separatedly, the pH of the solution is brought to the value of 7.4, by proceeding slowly and agitating continuously. Finally bidistilled water is added to make a volume of 10 000 ml. The solution is first sterilized through porcelain filter (G4 porosity) and then filtered in asepsis through a 0,45 /л membrane under nitrogen pressure. The filtered solution is distributed in asepsis in 250 ml bottles, which are carefully tightened under nitrogen flow and sealed. In preparing the solution, contact with air and light should be avoided. The solution, stored at + 5 °C, can be maintained for at least two years. Clinical trial Fifty fasting patients, submitted to surgical intervention for cataract and glaucoma, received intravenously 0,6—1 g/Kg body weight (the dosage was calculated according to the total solution concentration, e.g. 20%) of 10% glycerol + 10% sodium ascorbate. Administration was performed at a rate of 80 to 100 drops per minute, 30 to 60 minutes prior to surgery. In 22 patients, the intraocular pressure was measured at different time intervals (20—30—60 minutes) after the start of the infusion. In 7 patients, besides measuring the intraocular pressure, the following determinations were carried out at different time intervals: — serum osmolality — blood sugar levels — natremia and kalemia. Urines were tested for the presence of blood by microscopic examination (urinary sediment obtained by centrifugation) and their amount measured after 30 and 60 minutes from the start of the infusion. The intraocular pressure was evaluated by means of the Mackay-Marg electronic tonometer. The osmotic pressure was determined by means of the Fiske Osmometer. Blood sugar levels were evaluated with the ortho-Toluidine method, which is based on the photometric determination of the coloured compound which is formed by glucose and o-toluidine in acid medium and in hot water-bath. It should be emphasized that we had to discard both the enzymatic methods (because sodium ascorbate interferes in the reaction) and the other methods based on the determination of the reducing substances. As a matter of fact, 167
