THE CLEVEDON POSITIVE-PRESSURE RESPIRATOR

THE CLEVEDON POSITIVE-PRESSURE RESPIRATOR

971 in similar circumstances. If this is impossible, drainage must be provided, with the intention at a later date of implanting the fistula into the ...

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971 in similar circumstances. If this is impossible, drainage must be provided, with the intention at a later date of implanting the fistula into the alimentary tract. to

adopt

external

SUMMARY

A case is described of traumatic rupture of the hepatic ducts in a child, treated by choledochojejunostomy. The aetiology, clinical findings and surgical treatment are

discussed.

described the principles of the apparatus, the engineering details were not defined. With the financial approval of the South-Western Regional Hospital Board and the expertassistance of Mr. M. J. Willcocks, of Willcocks (Clevedon), Ltd., Instruments Section, a prototype was produced. Improved patterns were available by the middle of July, 1953. We now offer a preliminary report. ,

APPARATUS

-

REFERENCES

Edington, G. H. (1933) Brit. J. Surg. 20, 697. Garré, C. (1908) Festschrift f. L. Hermann. p. 22. Grimault, M. L. (1947) Mém. Acad. Chir. 73, 205. Lewis, K. M. (1938) Ann. Surg. 108, 237. Lysaght, A. C. (1939) Brit. J. Surg. 26, 646. O’Malley, R. D., Aufses, A. H. jun., Whipple, A. O. (1951) Surg. 134, 797. Rudberg, H. (1921) Münch, med. Wschr. 68, 1680. Waugh, G. E. (1916) Brit. J. Surg. 3, 868.

Ann.

THE CLEVEDON POSITIVE-PRESSURE

RESPIRATOR JAMES MACRAE M.D.

Glasg., F.R.F.P.S.,

D.P.H.

RESIDENT PHYSICIAN

G. D. W. MCKENDRICK M.A., B.M. Oxfd, M.R.C.P. DEPUTY PHYSICIAN

J. M. CLAREMONT M.B. Brist. ASSISTANT MEDICAL OFFICER

E. M. SEFTON M.R.C.S., D.C.H. ASSISTANT MEDICAL

OFFICER

R. V. WALLEY B.A., M.B. Camb.

The characteristics of the apparatus are evident in the accompanying figure. It consists of a slide-valve operated by electromagnets which in turn are actuated by electrolytic switches in a U-tube partly filled with acidified sodium-sulphate solution. The machine is powered by a 12V battery delivering 1 amp., maintained by a trickle The Clevedon machine is similar to that charger. designed by Bang, but the valve gear is original and electrolyte is used instead of floats in the U-tube. Medical air (British Oxygen Co.), enriched with oxygen, is supplied from large cylinders through a humidifier to a reservoir bag (an ordinary -football bladder) and so through the inlet valve of the machine to the patient in a circuit closed by the tracheal-tube cuff. The pulmonary pressure built up by the inspired air pushes the electrolyte fluid up to the second switch, which opens the expiratory valve, thus releasing expired air to the atmosphere. The electrolyte falls under gravity to reach the original switch and so opens the inspiratory valve for another cycle. The amount of air-oxygen mixture, the speed, the depth, and the inspiration/expiration ratio of respiration can all be controlled. The machine is of self-demand type and has an automatic safety valve. There is only one moving part, and the valve mechanism can be changed in less than 30 seconds without undoing any nuts or bolts. Relays are used to reduce the current passed by the electrolyte to about 30 mA, thus minimising electrolysis and sparking. The apparatus is relatively cheap (about 60), is portable, and can operate independently of a main

ASSISTANT MEDICAL OFFICER

HAM GREEN

HOSPITAL,

BRISTOL

THE

WHEN Lassen (1953) demonstrated in Copenhagen last year that positive-pressure respiration combined with tracheotomy could save life in certain types of poliomyelitis, it was obvious that treatment of this sort should be available in this country. Lassen’soriginal

method

electricity supply. MACHINE IN

USE

well-developed man, aged 21, was admitted at on Sept. 28, 1953, with severe poliomyelitis. At 7.30 A.M. he was placed in a Drinker-type tank respirator because of partial failure of his respiratory A

6.30

A.M.

re-

quired manual operation of the respirator and an almost indefinite supply of trained personnel. The advantages of an automatic type of positive-pressure apparatus was evident in Denmark, and Bang (1953) published details of such a machine. It is understood that automatic respirators have now been used in Denmark with varying success. In this country Pask (1953), Beaver (1953), and Russell and Schuster (1953) have developed similar equipment. In April of this year we acquired for this hospital a manual respirator such as was used in Denmark, and later added the Oxford inflator described by Macintosh (1953).

Since it seemed very difficult provide sufficient personnel to operate manual respirators in any number, we constructed an automatic respirator similar to that to

described by Bang.

Although Bang

The

apparatus : A, air and oxygen cylinders ; B, reservoir bag ; C, automatic respirator ; D2 trickle charger ; F, humidifier ; G, gas tube to patient ; H, tracheotomy tube ;;

battery ; E, J,

gas

inlet ; K,

relays.

gas

exhaust ; L, valve gear ;

M,

electrolytic switches

in

U-tube ;N,

electrical ,

972 muscles. During the day his paralysis spread, and by 6 P.M. the respiratory-muscle paralysis was almost complete. In addition he had developed bulbar involvement, with inability to swallow, and was accumulating pharyngeal mucus. Continued treatment in the tank respirator was obviously going to prove rapidly fatal, since it was impossible to keep the airway clear. It was decided to try the positive-pressure machine. The patient was transferred to a bed, and respiration was maintained with the manually operated Oxford inflator through a face mask. Tracheotomy under local anaesthesia was performed by one of us (J. M.), a small window being cut in the trachea and a cuffed endotracheal tube inserted. This was connected to the automatic respirator and satisfactory breathing was established at once. Maximum comfort was obtained with a mixture of 4 litres of air and 2 litres of oxygen a minute at a respiratory rate of 12 breaths a minute. The inspiration pressure was 16-20 cm. H2O. With this régime good air entry could be heard throughout all areas of both lung fields. The success of the respirator was best shown by the fact that the patient fell asleep for the first time in two

days. Nursing

carried out at a postural tilt of about From the beginning there was completely adequate aeration of the lungs. This automatic respirator has maintained the patient’s life up to the time of writing, and minor adjustments only have been required. For long periods the respirator The patient has been has worked without attention. comfortable and cheerful and has had adequate sleep. Heavy sedation has not been required. Œsophageal tubefeeding was instituted on the second day. General nursing, postural treatment, and catheterisation were all easily achieved and found to be a welcome change from the performance of similar tasks in the tank respirator. The patient started to recover his ability to swallow on the sixth day, and oesophageal tube-feeding is no longer necessary. On the twelth day some spontaneous respiration recommenced, and now (Oct. 27) the patient is able to breathe himself for periods of an hour. was

20°, head down.

Secretions accumulate in the tube and suction of the tube has been necessary at intervals of two to six.hours. It has only occasionally been necessary to suck out the main bronchi. The indications for suction seem to be simply the sound of rales in the tube audible at the bedside or conducted to the lung fields and heard through a stethoscope. There have been no signs of fluid accumulating in the smaller bronchi or alveoli. The endotracheal tube has been changed about daily. Although the difficulties of management have been considerably less than anticipated, there has been a doctor present in the ward at all times, and we feel that this is essential for safe supervision. SUMMARY

positive-pressure respirator which has only one moving part and works independently of a main electricity supply is presented. A case in which it is still being used is described. A

Our sincere thanks are due to Mr. M. J. Willcocks and his colleagues for the generous help and beautiful engineering technique which they have put at our disposal in producing this machine. many

REFERENCES

Bang, C. (1953) Lancet, i, 723. Beaver, R. A. (1953) Ibid, ii, 200. Lassen, H. C. A. (1953) Ibid, i, 37. Macintosh, R. R. (1953) Brit. med. J. ii, 202. Pask, E. A. (1953) Lancet, ii, 141. Russell, W. R., Schuster, E. (1953) Ibid, p. 707.

Medical Societies BRITISH ORTHOPÆDIC ASSOCIATION THE association’s annual meeting was held at Birmingham on Oct. 23 and 24. Sir REGINALD WATSON-JONES was in the chair on the first day; and on the second day he was succeeded by the new president, Prof. BRYAN McFARLAND. For the first time in the association’s history an instructional course in orthopaedic surgery was given on the day before the meeting. This course was attended by nearly two hundred young surgeons and senior orthopaedic registrars, as well as by some of the fellows and members of the association. Presidential Address

Sir REGINALD WATSON-JONES, the retiring president, said that the association had created strong ties between the orthopaedic surgeons of Great Britain, the Common. wealth countries, and the U.S.A. ; it had given strong support to the foundation of the New Zealand Ortho. paedic Association and the South African Orthopædic Association ; and with equal generosity from the United States and Canada had secured the foundation of travelling fellowships for young orthopsedic surgeons between the United States, Canada, and Britain, with a share by other countries of the Commonwealth. The association, mindful of the value of tradition, had recently taken steps to stimulate interest in historical treasures relating to orthopaedic and allied subjects. A collection of such treasures was to be housed at the Royal College of Surgeons of England, where a selection would always be on view in the college hall.

Acrylic Replacement in Fractures of Femur Mr. DAVID LE VAY described his experiences with replacement arthroplasty of the hip by a prosthesis of the Judet type as the primary treatment of subcapital fractures of the neck of the femur. The method was well justified in the elderly. Most patients had been allowed up 4-5 weeks after the operation, and the average length of stay in hospital was 10 weeks. Although there had been a tendency for the head to migrate into a varus position a point of stability was reached beyond which no further displacement occurred. Insertion of the prosthesis to lie in slight valgus offered advantages. Mr. 0. J. VAUGHAN-JACKSON, who had done replacement arthroplasty in 34 cases, suggested that it was still too early finally to assess its merits. At best it did not give a normal joint, which was not true of a successful nailing operation; it could therefore not be recommended for all patients with femoral-neck fractures-certainly not for those in their fifties or sixties. Of his 34 cases, the operation was tolerated well in 32 and poorly in 1 ; 1 patient died. The main local complication was fracture of the prosthesis (4 cases); the use of metal prostheses in place of plastic would probably solve the problem of breakage. Walking -was resumed 5-6 weeks after operation. Most patients preferred to use sticks for at least 6 months, but none complained of severe pain. Mr. G. N. GOLDEN (Guildford) reported 60 cases of Judet arthroplasty for fracture which he had reviewed in collabora. tion with Mr. C. C. M. Murray (Southsea) and Mr. A. G. Ord (Portsmouth). The results were good in 70% and satisfactory in a further 15%.

The

Valgus Foot

Mr. G. K. RosE (Shrewsbury) said that the dividing-line between the normal and the " valgus " or " pronated" foot was ill-defined, and the indications for treatment indefinite. He had undertaken a long-term investigation of the feet of 177 children aged 6-8 years. His conclusions were that some valgus shift was normal, but that there was no difference in the valgus index between boys and girls. The significance of valgus shift was greatest when the axis of the knee was medial to that of the foot and least when the axis of the knee The essential pathological was lateral to that of the foot. feature in the abnormal valgus foot was strain of the peritalar joint, not simply an abnormal position of the joint.