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AVERTIN FOR CHILDREN
270
CLINICAL OXYGEN ESTIMATION
research fellowships at 1:250 per annum for candidates of similar qualifications who have already had some experience in the use of research methods. Each fellowship will be tenable for one year, and possibly for a second year at S300 per annum. These fellowships are intended as probationary appointments for research in clinical science or experimental pathology under suitable direction in this country. Research expenses will be provided in addition to stipend. Forms of application can be obtained from the Secretary, Medical Research Council, 38, Old Queenstreet, London, S.W.1, and should be filled up and returned to him before Oct. 12th, 1936. AVERTIN FOR CHILDREN
’
THE advantages of basal narcosis for children-i.e., the easy introduction of some drug which robs the child of all fear before the actual administration of an an2esthetic-are undoubted, whatever opinions may be held with regard to the same procedure for adult patients. Without some aid of this kind it is easy to cause in the small child an amount of alarm which is literally never forgotten. Every anaesthetist of has of this in the apparently had experience proof unreasonable terror exhibited by an otherwise normal child who is to take an anaesthetic and remembers an earlier experience. Not the blandishments of the most sympathetic or skilful can always allay these fears ; but an appropriate dose of avertin will not upset the small patient in any way and will allow an anaesthetic to be given in perfect peace. Some anaesthetists prefer paraldehyde for young subjects and we do not think that its objectionable smell matters, so far as the patient is concerned, to the extent that Dr. H. K. Ashworth,’ who has recently been investigating the subject, appears to hold. He is concerned, however, to demonstrate the special value of avertin for producing nasal narcosis in children. His article is based on nearly 6000 administrations and gives in detail the dosage, technique, and after-care employed. There was one death in the series, of a boy 21 hours after being given avertin, and although full details are given, the true explanation of the fatality is not clear. Dr. Ashworth certainly makes out a strong case for the routine use of avertin before operations on young children. CLINICAL OXYGEN ESTIMATION
IN using the oxygen tent it is necessary to analyse the air in the tent at about hourly intervals to control the supply of the gas. It is essential that the apparatus for doing this should be foolproof and able to give standard results in the hands of different and inexperienced assistants. On p. 250 in a note on the tent, Dr. D. C. Reavell recommends certain improvements in the method generally used for estimating oxygen. This was devised by E. P. Poulton and J. W. Shackle,2 and consists of a pipette fitted with a tap, a small glass side-tube, and a rubber bulb that can hold about 2 oz. of fluid. The part nearest the tap, 4 cm. long, is graduated in percentages and the fluid level in the pipette can be altered by pushing in or out a glass plunger held in the side-tube by rubber tubing. The apparatus is filled with a mixture of pyrogallic acid and caustic potash ; it can be emptied of air by squeezing the bulb and filled with the sample through rubber tubing leading from the tent ; after repeated inversions the percentage of oxygen absorbed can be read. Dr. Reavell suggests that the side-tube and the base 1 Arch. Dis. Child., June, 1936, p. 157. 2 THE LANCET, 1933, i., 248.
should be made of stainless steel, the fluid level being adjusted by a piston moved by a screw, and the rubber bulb fitted to a metal adapter. It happens that J. E. F. Risemaii and G. Lesnick3 have just described an alternative method which gives an error of only 2 per cent. compared with 5 per cent. for Poulton and Shackle’s original pipette. Though it is rather more complicated, they say that it can be used for the first time without difficulty by nurses and others unskilled in gas analysis. The apparatus is similar in principle to that used in the classical Haldane’s method. The nozzles of ordinary 10 c.cm. and 30 c.cm. hypodermic syringes are connected end-to-end by a three-way valve. The larger syringe, the absorbing chamber, contains tightly rolled copper gauze, and its piston is replaced by a rubber stopper holding a glass U-tube. Riseman and Lesnick find that a solution of ammonium nitrate in ammonium hydroxide is the most satisfactory absorbing fluid. By withdrawing the piston of the 100 c.cm. syringe the sample of air is taken through the three-way valve, by a turn of which the air can be driven into the large syringe. As the oxygen is absorbed the level in the U-tube falls, and when it becomes stationary the percentage can be read off from a scale. The air is expelled by turning the valve to the third position, and the apparatus is ready for the next estimation. The absorbing fluid allows 40 of these estimations before it needs to be renewed, when a sediment forms ; refilling is a simple and quick operation. The apparatus is mounted in a wooden box fixed permanently to the oxygen tent. The greater expense of Dr. Reavell’s modifications and of this apparatus would be excused by greater accuracy and simplicity in action and by the time saved in making the many necessary estimations. ACUTE HÆMORRHAGIC PANCREATITIS
AN experimental and histological study of the pathogenesis of acute hsemorrhagic pancreatitis suggests to A. R. Rich and G. Lyman Duff 4 that in this disease a peculiar type of vascular necrosis occurs in the pancreas. This necrosis, according to the authors, affects both arteries and veins ; it is patchy in its distribution and is associated with a hyaline appearance of the wall resembling that found in the vessels of subjects of hypertension. They look upon the haemorrhage which occurs into the gland as the result of this vascular lesion, and believe its cause to be escape of trypsin into the gland-
tissue. The action of this ferment upon the vessels demonstrated by injecting it into the abdominal wall in dogs, which were subsequently found to show an identical condition of the regional vessels. Similar experiments with sterile bile gave negative results. Trypsinogen, obtained directly from the pancreatic duct, had precisely the same effect as trypsin activated by enterokinase. Boiling rendered the trypsin inactive in this respect. The escape of trypsinogen into the tissues of the gland may result from trauma, infarction and necrosis of the acini, infection, retrojection of bile, and rupture of the acini or backpressure due to obstruction of the ducts. The latter is held to be the common cause. Evidence of ductobstruction in the shape of dilated ductules or acini was found in 23 out of a series of 24 cases of acute haemorrhagic pancreatitis examined post mortem. It was rarely ofa gross character (e.g., a gall-stone in the common duct) ; much more commonly it resulted from metaplasia of the duct epithelium in the smaller was
3 New Eng. Med. Jour., July 9th, 1936, p. 65. 4 Bull. Johns Hopkins Hosp., March, 1936, p. 212
CLINICAL OXYGEN ESTIMATION
research fellowships at 1:250 per annum for candidates of similar qualifications who have already had some experience in the use of research methods. Each fellowship will be tenable for one year, and possibly for a second year at S300 per annum. These fellowships are intended as probationary appointments for research in clinical science or experimental pathology under suitable direction in this country. Research expenses will be provided in addition to stipend. Forms of application can be obtained from the Secretary, Medical Research Council, 38, Old Queenstreet, London, S.W.1, and should be filled up and returned to him before Oct. 12th, 1936. AVERTIN FOR CHILDREN
’
THE advantages of basal narcosis for children-i.e., the easy introduction of some drug which robs the child of all fear before the actual administration of an an2esthetic-are undoubted, whatever opinions may be held with regard to the same procedure for adult patients. Without some aid of this kind it is easy to cause in the small child an amount of alarm which is literally never forgotten. Every anaesthetist of has of this in the apparently had experience proof unreasonable terror exhibited by an otherwise normal child who is to take an anaesthetic and remembers an earlier experience. Not the blandishments of the most sympathetic or skilful can always allay these fears ; but an appropriate dose of avertin will not upset the small patient in any way and will allow an anaesthetic to be given in perfect peace. Some anaesthetists prefer paraldehyde for young subjects and we do not think that its objectionable smell matters, so far as the patient is concerned, to the extent that Dr. H. K. Ashworth,’ who has recently been investigating the subject, appears to hold. He is concerned, however, to demonstrate the special value of avertin for producing nasal narcosis in children. His article is based on nearly 6000 administrations and gives in detail the dosage, technique, and after-care employed. There was one death in the series, of a boy 21 hours after being given avertin, and although full details are given, the true explanation of the fatality is not clear. Dr. Ashworth certainly makes out a strong case for the routine use of avertin before operations on young children. CLINICAL OXYGEN ESTIMATION
IN using the oxygen tent it is necessary to analyse the air in the tent at about hourly intervals to control the supply of the gas. It is essential that the apparatus for doing this should be foolproof and able to give standard results in the hands of different and inexperienced assistants. On p. 250 in a note on the tent, Dr. D. C. Reavell recommends certain improvements in the method generally used for estimating oxygen. This was devised by E. P. Poulton and J. W. Shackle,2 and consists of a pipette fitted with a tap, a small glass side-tube, and a rubber bulb that can hold about 2 oz. of fluid. The part nearest the tap, 4 cm. long, is graduated in percentages and the fluid level in the pipette can be altered by pushing in or out a glass plunger held in the side-tube by rubber tubing. The apparatus is filled with a mixture of pyrogallic acid and caustic potash ; it can be emptied of air by squeezing the bulb and filled with the sample through rubber tubing leading from the tent ; after repeated inversions the percentage of oxygen absorbed can be read. Dr. Reavell suggests that the side-tube and the base 1 Arch. Dis. Child., June, 1936, p. 157. 2 THE LANCET, 1933, i., 248.
should be made of stainless steel, the fluid level being adjusted by a piston moved by a screw, and the rubber bulb fitted to a metal adapter. It happens that J. E. F. Risemaii and G. Lesnick3 have just described an alternative method which gives an error of only 2 per cent. compared with 5 per cent. for Poulton and Shackle’s original pipette. Though it is rather more complicated, they say that it can be used for the first time without difficulty by nurses and others unskilled in gas analysis. The apparatus is similar in principle to that used in the classical Haldane’s method. The nozzles of ordinary 10 c.cm. and 30 c.cm. hypodermic syringes are connected end-to-end by a three-way valve. The larger syringe, the absorbing chamber, contains tightly rolled copper gauze, and its piston is replaced by a rubber stopper holding a glass U-tube. Riseman and Lesnick find that a solution of ammonium nitrate in ammonium hydroxide is the most satisfactory absorbing fluid. By withdrawing the piston of the 100 c.cm. syringe the sample of air is taken through the three-way valve, by a turn of which the air can be driven into the large syringe. As the oxygen is absorbed the level in the U-tube falls, and when it becomes stationary the percentage can be read off from a scale. The air is expelled by turning the valve to the third position, and the apparatus is ready for the next estimation. The absorbing fluid allows 40 of these estimations before it needs to be renewed, when a sediment forms ; refilling is a simple and quick operation. The apparatus is mounted in a wooden box fixed permanently to the oxygen tent. The greater expense of Dr. Reavell’s modifications and of this apparatus would be excused by greater accuracy and simplicity in action and by the time saved in making the many necessary estimations. ACUTE HÆMORRHAGIC PANCREATITIS
AN experimental and histological study of the pathogenesis of acute hsemorrhagic pancreatitis suggests to A. R. Rich and G. Lyman Duff 4 that in this disease a peculiar type of vascular necrosis occurs in the pancreas. This necrosis, according to the authors, affects both arteries and veins ; it is patchy in its distribution and is associated with a hyaline appearance of the wall resembling that found in the vessels of subjects of hypertension. They look upon the haemorrhage which occurs into the gland as the result of this vascular lesion, and believe its cause to be escape of trypsin into the gland-
tissue. The action of this ferment upon the vessels demonstrated by injecting it into the abdominal wall in dogs, which were subsequently found to show an identical condition of the regional vessels. Similar experiments with sterile bile gave negative results. Trypsinogen, obtained directly from the pancreatic duct, had precisely the same effect as trypsin activated by enterokinase. Boiling rendered the trypsin inactive in this respect. The escape of trypsinogen into the tissues of the gland may result from trauma, infarction and necrosis of the acini, infection, retrojection of bile, and rupture of the acini or backpressure due to obstruction of the ducts. The latter is held to be the common cause. Evidence of ductobstruction in the shape of dilated ductules or acini was found in 23 out of a series of 24 cases of acute haemorrhagic pancreatitis examined post mortem. It was rarely ofa gross character (e.g., a gall-stone in the common duct) ; much more commonly it resulted from metaplasia of the duct epithelium in the smaller was
3 New Eng. Med. Jour., July 9th, 1936, p. 65. 4 Bull. Johns Hopkins Hosp., March, 1936, p. 212