Correspondence
successfully, that the flexible hoses for individual gases should be manufactured in materials of different colours. I understand that the British Standard hose for nitrous oxide will be manufactured in blue when the standard is introduced. In my own District, strict procedures have been approved for work on pipelines and even I respect the discipline of not ‘botching’. We tell engineers when the colour bands on the pipelines become insecure and have instituted a routine test of the gases produced by the anaesthetic machines using a cheap portable oxygen meter. I believe that the Association should press for colour coding of gas pipelines now if further delay of the standard is anticipated, and that the need to be alert to faults in the equipment which we use should be repeatedly stressed to all concerned with anaesthesia. Lewisham Hospital, Lewisham High Street, London, SE13 6LH
J.M. CUNDY
A comment
As Chairman of the B.S.I. Sub-committee SGS/15/3, which is attempting to formulate a ‘pipeline standard‘, I am grateful for the opportunity of replying to Dr Cundy’s letter. Obviously, Dr Cundy has not seen the Draft pipeline standard which was distributed in May 1977, the closing date for comment being 29/7/1977. Some 3000 copies of this draft were sent out including one to each A.H.A. The fact that D r Cundy has evidently not seen it is but additional evidence of the failure of communication in administrative circles in the N.H.S.,which I tried to rectify in the September issue (Anaesthesia, 1977, 32, 809). Most of the points Dr Cundy raises are answered in the draft. The remarkable delay in the production of the draft (11 years) is in no way due to the Association of Anaesthetists, who only became involved directly with the work of this Committee two years ago. It says much for the willingness of members of the Sub-committee drawn from industry, the D.H.S.S. and anaesthetists that we produced such detailed recommendations based upon exhaustive trials within 2 years. Perhaps I could be allowed a general comment on colour coding of hoses? This must never be considered a primary safety factor as experience has shown how easily it can be defeated; we believe
923
will lie with inspection of hoses and their replacement with manufactured hose assemblies which comply with the provisions and tests of the standard; colour coding is thus of secondary importance. Even so, we have recently tested completely coloured hose of foreign manufacture, which met the anti-static precautions. This has been done by making the hose in two parts, the inner pressure hose being of low electrical resistance approximately I0 Kohms/cm with an outer sheath of normal rubber mix, coloured appropriately, which has a resistance of > 50 Mohm/ cm. This high resistance outer sheath is then effectively earthed to prevent build up of static electricity. Such hoses are not precluded by the terms of the standard. Finally, may I comment on the use of an oxygen analyser? If any test equipment is to be used we must know what questions we hope it will answer. There are three generally accepted terms used in pipeline testings; identity, purity and pollutant contamination. The oxygen analyser will identify the oxygen pipeline, but will not test the purity or pollutant content of the issuing gas. It will not test N 2 0even by exclusion-the issuing gas could well be North Sea gas. I believe the use of oxygen analysers is unwarranted because the recommendations of the standard will provide a greater degree of safety for all piped gases and it is not only misconnection of the oxygen hoses which must be prevented. This type of accident has been the commonest in the past, but we must legislate for the future. The testing of piped gases for identity, purity and freedom from pollution can be done by the use of the new quadrapole mass spectrometers provided sensitive chemical methods are used to identify the presence of the higher oxides of nitrogen which would occur naturally from pure NzO in the ion chamber of the mass spectrometer. This aspect of quality control is not part of the standard but we have demonstrated its use in the field by testing a suspect pipeline 40 miles from this department, within 20 minutes of arrival; the mass spectrometer maintaining its vacuum during transportation in the boot of a car. We hope to publish results of this mode of use of this instrument when the instrument can be released for further trials, such is the demand for its use in other fields of research. Department of Anaesthesia, Queen Elizabeth Hospital, Birmingham, B15 2TH
JOHN S . ROBINSON Chairman BSI Committee SGS/15/3
Anaesthetic management of insulinorna Other reports It is surprising that the authors of ‘Anaesthetic management of insulinoma’ (Anaesthesia, 1977, 32, 261) should state that only four cases have been
previously reported in the literature. They would appear to be unaware of two recent interesting papers by Colella and Vandam (1972) and Yasunaka (1973) in which the anaesthetic management of
924
Correspondence
hyperinsulinism is considered.'S2 Furthermore, many cases have been described from a swgical ~iewpoint.~.~ The choice of anaesthetic technique for these patients is of little significance. We have used both halothane and neuroleptanalgesia without difficulty. Provided that blood sugar estimations are frequent and appropriate quantities of dextrose are administered intravenously preoperatively and during surgery, severe hypoglycaemia should neither occur, nor should the effects of anaesthetic agents cause confusion. Department of Anesthesiology, Mount Sinai Medical Center, New York, New York 10029
R. MILLER A.U. PATEL
A reply from Dr Chari
If Dr Miller and Dr Patel have used halothane and neuroleptanalgesia without any difficulty, we certainly would not like to contradict their experience. We also, in our communication have made the point that maintenance of adequate blood sugar levels during pre-operative and intra-operative period before enucleation of the adenoma is of prime importance to prevent problems. There, of course, is no doubt that there is no paucity of literature from a surgical viewpoint. But we have deliberately
References 1. COLELLA, J.J. & VANDAM, L.D. (1972) Diethyl ether
anesthesia for a patient with hyperinsulinism. Anesthesiology, 37, 254. 2. YASUNAKA, H. (1973) Management of atients with insulinoma. Japanese Journal of Anaesthesiology, 22, 829.
3. HARTSUCK, J.M.& BROOK, J.R. (1969) Functioning beta islet cell tumors. American Journal of Surgery, 117, 541. 4. SCHNELLE, N., MOLNAR, G.D. & FERRIS,D.O. (1971). Circulating glucose and insulin in surgery for insulinomas. Journal of the American Medical Association, 217, 1072.
omitted these references because we concentrated mainly on anaesthetic management. At the same time we would like to thank Drs Miller and Patel for bringing to our notice the papers by Colella and Vandam, and Yasunaka, which we, unfortunately, had overlooked. Department of Anaesthesiology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
P. CHARI
Stress in operating theatre personnel In recent years attention has been focussed on the health risk run by operating theatre personnel. Rosenberg and Kirves' in the Finnish survey suggested that excessive work loads rather than anaesthetic gases are the major cause of obstetrical disturbances among nurses working in operating rooms. Smitha pointed out that we should not necessarily seek a single cause for these alleged potential hazards of being an anaesthetist. Contributory causes could include occupational stress arising from the incidence of uncertainty and anticipation exacerbated by irregular routine, fatigue and emotional factors. This study was undertaken to establish whether or not working in an operating theatre environment led to increased stress as evidenced by altered physiological and biochemical responses and to compare some of the findings with those obtained in nurses working in wards. Two series of experiments were undertaken, the first on two separate groups of workers. The first group was composed of nine male and six female volunteers, ranging in age from 24 to 60 years, who normally worked in the operating theatre as doctors, nurses and technicians. The second group consisted of six male and nine female nurses from the wards, their ages ranging from 26 to 57 years. All subjects were in normal health and were
not taking any drugs, and were studied between the hours of 9.00 a.m. and 12.00 noon; there was no systematic difference in the time of day during which different groups were investigated. The measurements of pulse rate and blood pressure were taken at 9.00 a.m. and again at 12.00 noon. Blood pressure was taken by auscultatory method. Blood samples for cortisol estimation were also withdrawn at 9.00 a.m. and 12.00 noon. The measurement of plasma cortisol was made by the method of M a t t i n g l ~In . ~ the second series, the urinary output of adrenaline and noradrenaline was estimated in six healthy male volunteers, ranging in age from 26 to 48years, comprising of three anaesthetists, two surgeons and one theatre technician. The urine samples were collected in two periods from
9.00a.m.to12.00noonand2.00p.m.to5.00p.m.,on operating days and non-operating days, thus using each subject as his own control. The details in the experimental studies were strictly standardised, including food and fluid intake and urine collections. The volume of urine was measured during each period. Catecholamines were extracted from the acidified urine by the method of Varley.' Adrenaline and noradrenaline were estimated fluorimetrically by the method of Weil-Malherbe and Bone.5 The results showed that there was no obvious o r
successfully, that the flexible hoses for individual gases should be manufactured in materials of different colours. I understand that the British Standard hose for nitrous oxide will be manufactured in blue when the standard is introduced. In my own District, strict procedures have been approved for work on pipelines and even I respect the discipline of not ‘botching’. We tell engineers when the colour bands on the pipelines become insecure and have instituted a routine test of the gases produced by the anaesthetic machines using a cheap portable oxygen meter. I believe that the Association should press for colour coding of gas pipelines now if further delay of the standard is anticipated, and that the need to be alert to faults in the equipment which we use should be repeatedly stressed to all concerned with anaesthesia. Lewisham Hospital, Lewisham High Street, London, SE13 6LH
J.M. CUNDY
A comment
As Chairman of the B.S.I. Sub-committee SGS/15/3, which is attempting to formulate a ‘pipeline standard‘, I am grateful for the opportunity of replying to Dr Cundy’s letter. Obviously, Dr Cundy has not seen the Draft pipeline standard which was distributed in May 1977, the closing date for comment being 29/7/1977. Some 3000 copies of this draft were sent out including one to each A.H.A. The fact that D r Cundy has evidently not seen it is but additional evidence of the failure of communication in administrative circles in the N.H.S.,which I tried to rectify in the September issue (Anaesthesia, 1977, 32, 809). Most of the points Dr Cundy raises are answered in the draft. The remarkable delay in the production of the draft (11 years) is in no way due to the Association of Anaesthetists, who only became involved directly with the work of this Committee two years ago. It says much for the willingness of members of the Sub-committee drawn from industry, the D.H.S.S. and anaesthetists that we produced such detailed recommendations based upon exhaustive trials within 2 years. Perhaps I could be allowed a general comment on colour coding of hoses? This must never be considered a primary safety factor as experience has shown how easily it can be defeated; we believe
923
will lie with inspection of hoses and their replacement with manufactured hose assemblies which comply with the provisions and tests of the standard; colour coding is thus of secondary importance. Even so, we have recently tested completely coloured hose of foreign manufacture, which met the anti-static precautions. This has been done by making the hose in two parts, the inner pressure hose being of low electrical resistance approximately I0 Kohms/cm with an outer sheath of normal rubber mix, coloured appropriately, which has a resistance of > 50 Mohm/ cm. This high resistance outer sheath is then effectively earthed to prevent build up of static electricity. Such hoses are not precluded by the terms of the standard. Finally, may I comment on the use of an oxygen analyser? If any test equipment is to be used we must know what questions we hope it will answer. There are three generally accepted terms used in pipeline testings; identity, purity and pollutant contamination. The oxygen analyser will identify the oxygen pipeline, but will not test the purity or pollutant content of the issuing gas. It will not test N 2 0even by exclusion-the issuing gas could well be North Sea gas. I believe the use of oxygen analysers is unwarranted because the recommendations of the standard will provide a greater degree of safety for all piped gases and it is not only misconnection of the oxygen hoses which must be prevented. This type of accident has been the commonest in the past, but we must legislate for the future. The testing of piped gases for identity, purity and freedom from pollution can be done by the use of the new quadrapole mass spectrometers provided sensitive chemical methods are used to identify the presence of the higher oxides of nitrogen which would occur naturally from pure NzO in the ion chamber of the mass spectrometer. This aspect of quality control is not part of the standard but we have demonstrated its use in the field by testing a suspect pipeline 40 miles from this department, within 20 minutes of arrival; the mass spectrometer maintaining its vacuum during transportation in the boot of a car. We hope to publish results of this mode of use of this instrument when the instrument can be released for further trials, such is the demand for its use in other fields of research. Department of Anaesthesia, Queen Elizabeth Hospital, Birmingham, B15 2TH
JOHN S . ROBINSON Chairman BSI Committee SGS/15/3
Anaesthetic management of insulinorna Other reports It is surprising that the authors of ‘Anaesthetic management of insulinoma’ (Anaesthesia, 1977, 32, 261) should state that only four cases have been
previously reported in the literature. They would appear to be unaware of two recent interesting papers by Colella and Vandam (1972) and Yasunaka (1973) in which the anaesthetic management of
924
Correspondence
hyperinsulinism is considered.'S2 Furthermore, many cases have been described from a swgical ~iewpoint.~.~ The choice of anaesthetic technique for these patients is of little significance. We have used both halothane and neuroleptanalgesia without difficulty. Provided that blood sugar estimations are frequent and appropriate quantities of dextrose are administered intravenously preoperatively and during surgery, severe hypoglycaemia should neither occur, nor should the effects of anaesthetic agents cause confusion. Department of Anesthesiology, Mount Sinai Medical Center, New York, New York 10029
R. MILLER A.U. PATEL
A reply from Dr Chari
If Dr Miller and Dr Patel have used halothane and neuroleptanalgesia without any difficulty, we certainly would not like to contradict their experience. We also, in our communication have made the point that maintenance of adequate blood sugar levels during pre-operative and intra-operative period before enucleation of the adenoma is of prime importance to prevent problems. There, of course, is no doubt that there is no paucity of literature from a surgical viewpoint. But we have deliberately
References 1. COLELLA, J.J. & VANDAM, L.D. (1972) Diethyl ether
anesthesia for a patient with hyperinsulinism. Anesthesiology, 37, 254. 2. YASUNAKA, H. (1973) Management of atients with insulinoma. Japanese Journal of Anaesthesiology, 22, 829.
3. HARTSUCK, J.M.& BROOK, J.R. (1969) Functioning beta islet cell tumors. American Journal of Surgery, 117, 541. 4. SCHNELLE, N., MOLNAR, G.D. & FERRIS,D.O. (1971). Circulating glucose and insulin in surgery for insulinomas. Journal of the American Medical Association, 217, 1072.
omitted these references because we concentrated mainly on anaesthetic management. At the same time we would like to thank Drs Miller and Patel for bringing to our notice the papers by Colella and Vandam, and Yasunaka, which we, unfortunately, had overlooked. Department of Anaesthesiology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
P. CHARI
Stress in operating theatre personnel In recent years attention has been focussed on the health risk run by operating theatre personnel. Rosenberg and Kirves' in the Finnish survey suggested that excessive work loads rather than anaesthetic gases are the major cause of obstetrical disturbances among nurses working in operating rooms. Smitha pointed out that we should not necessarily seek a single cause for these alleged potential hazards of being an anaesthetist. Contributory causes could include occupational stress arising from the incidence of uncertainty and anticipation exacerbated by irregular routine, fatigue and emotional factors. This study was undertaken to establish whether or not working in an operating theatre environment led to increased stress as evidenced by altered physiological and biochemical responses and to compare some of the findings with those obtained in nurses working in wards. Two series of experiments were undertaken, the first on two separate groups of workers. The first group was composed of nine male and six female volunteers, ranging in age from 24 to 60 years, who normally worked in the operating theatre as doctors, nurses and technicians. The second group consisted of six male and nine female nurses from the wards, their ages ranging from 26 to 57 years. All subjects were in normal health and were
not taking any drugs, and were studied between the hours of 9.00 a.m. and 12.00 noon; there was no systematic difference in the time of day during which different groups were investigated. The measurements of pulse rate and blood pressure were taken at 9.00 a.m. and again at 12.00 noon. Blood pressure was taken by auscultatory method. Blood samples for cortisol estimation were also withdrawn at 9.00 a.m. and 12.00 noon. The measurement of plasma cortisol was made by the method of M a t t i n g l ~In . ~ the second series, the urinary output of adrenaline and noradrenaline was estimated in six healthy male volunteers, ranging in age from 26 to 48years, comprising of three anaesthetists, two surgeons and one theatre technician. The urine samples were collected in two periods from
9.00a.m.to12.00noonand2.00p.m.to5.00p.m.,on operating days and non-operating days, thus using each subject as his own control. The details in the experimental studies were strictly standardised, including food and fluid intake and urine collections. The volume of urine was measured during each period. Catecholamines were extracted from the acidified urine by the method of Varley.' Adrenaline and noradrenaline were estimated fluorimetrically by the method of Weil-Malherbe and Bone.5 The results showed that there was no obvious o r
