- Email: [email protected]
OPERATING-THEATRES
1169
itself of its normal output of carbon dioxide despite the lowered partial pressure of carbon dioxide, and it can do so only
of double-ended autoclaves with one end accessible the sink room and the other only from the zone C.
by some adjustment in the distribution and flow of gas in the lungs, whether by a response of a respiratory centre to a high bicarbonate level, or by some other mechanism.
Air Changes Dr. Blowers 2 has previously shown that the background count of bacteria is reduced as the number of air changes rises. It appears, therefore, that far cleaner air would be achieved if the minimum number of changes in the operating-room and sterile work room were at least 20 per hour and in all other rooms within the suite were at least 10 per hour.
Carbohydrate metabolism produces equal quantities of hydrogen and bicarbonate ions. If too much of the hydrogen ion leaks through the kidneys, some bicarbonate must be stranded; and no amount of breathholding short of anoxia will prevent the consequent high concentration of bicarbonate, raised pH and lowered pCÛ2’ Hospital for Sick Children, London, W.C.1.
T. H. HUGHES-DAVIES.
OPERATING-THEATRES
SiR,—The report to the Medical Research Council (Nov. 10, p. 945) is a very thorough survey of problems associated with the ventilation of operating-room suites, but the inadequacy and vagueness of some of the conclusions show that a considerable amount of research has still to be done before definite recommendations can be given to architects and engineers in the form of a typical specification. Would it not have been wiser for the committee to have integrated their findings with those of the hospital engineering research unit at Glasgow and also to have tapped the wealth of information, about air filtration and bacteria, that is available at the War Department’s Establishments at Porton ? And made reference to the recent official American publication1 compiled by the U.S. Department of Health, Education and Welfare and the Department of U.S. Army Chemical Corps ? The following observations are submitted not as conclusions but as points of discussion: Position of the Operating-suite It is agreed that " stack effect " will cause airborne particles to rise to the top floor, but good architecture and ventilating design can readily prevent contamination of top-floor operating-suites. The importance of having space to house ventilation ducts, piped services, fans, filters, &c., cannot be over-emphasised. Operating-suites on lower floors restrict the space available for services, maintenance, alterations, and additions, so unless funds are available to provide a very preferable to adequate basement or service area, it appears " service floor ". use the top floor with a roof space to use as a Careful design can deal with noise and solar heat.
Arrangement of Rooms and their Ventilation The recommended zoning arrangement is in principle very satisfactory-especially the provision of airlocks ". But in the detailed design would it not be desirable to recommend that the changing-rooms be divided into " dirty " and clean areas, whereby dirty clothes are removed in the dirty area, the staff then wash or shower before entering the clean area, to don the sterile garments ? The air pressure in the "
"
"
"
"
"
"
"
"
clean
area
would of
course
be above that of the
dirty
area.
Sterilising-room In view of the dissipation of heat in the sterilising-room and the resultant convection currents which cause air transference to adjacent rooms, it seems that a recommendation should be made to house the autoclaves in a room, within zones B or C but separated from the operating-room by a ventilated lobby, and to provide the sterilising-room with about 30 air changes per hour of dust-free sterile air, from its own plenum ventilation plant. By a method of this sort, the ambient temperature of the sterilising-room can be maintained at about that of the communicating corridor or lobby and therefore undesirable air transference reduced. More consideration could have been given to the provision 1. Air Filtration of Microbial Particles. U.S. Education and Welfare Department of U.S.
June, 1962.
Department of Health Army Chemical Corps.
only from
Air Pressure It seems that what to do with the air discharged from the various rooms has not been seriously considered. Both the methods recommended have hazards from the bacteriological viewpoint. Firstly, the report stated that the exhaust apertures can discharge into a common duct. The hazard here is that the resistance to air-flow in the duct would vary as the different doors in the suite were used; this could cause a back pressure in the common duct that might result in air from a bacteriologically dirty duct or room flowing into a sterile room and general disturbances to the design. The other suggestion is " to reduce the total air volume of ventilating air, and the number of balanced flaps required, by allowing the air to pass from one zone into an adjacent part of the neighbouring lower pressure zone ". Surely this must be wrong; even with clean operations the air passing from the operating-room must be classed as dirty ", but when a dirty operation is carried out it is known that the air can become very heavily contaminated with pathogenic organisms. Can it be prudent to purposely pass this air into the corridor or the changing-room where the sterile clothes are stored ? The stated relative working pressures are lower than thought desirable. The pressure difference between clean rooms and corridors in pharmaceutical laboratories, &c., is frequently 0-1 in. water gauge (w.g.) and more. Why therefore are differences of 0-02 in. w.g. recommended ? In practice, such low pressures are difficult to maintain; minimum pressure differences of 0-1 in. w.g. should be sought, and inclined gauges 0-0-5 in. w.g. (type 504, Airflow Developments Ltd.) should be fitted to indicate pressure differences. "
Air Filtration It is stated that " filtration of the input air down to 5 microns is bacteriologically adequate ". Is this in fact beyond dispute ? To achieve clean and sterile air conditions in laboratory animal houses, pharmaceutical laboratories, and various other clean areas, it has been found necessary to install filtration plant that virtually removes all particles down to the size of less than 0-01 microns. The filters recommended in the report are used normally as pre-filters for the above applications or as the final filters for normal commercial filter applications. These filters permit the transfer of many hundreds or even a thousand times more dust particles, each of which possibly may become a carrier of germs liberated by the patient or theatre staff. From the report it can be assumed that germs or agglomeration of germs of less than 5 microns will not cause infection ? It is understood there are a number of modern operatingtheatres where the 5-micron standard of filters were installed and have not proved satisfactory, resulting in the installation of additional high-grade terminal filters’ (E. N. Mackley Ltd., Gateshead). Apart from supplying sterile air into the theatre and ancillary rooms the terminal filters prevent convection currents causing the air ducts to become contaminated if the ventilation plant fails or is shut down. They also will remove bacteria that might breed in the air washers, &c. The maintenance cost of these terminal filters, which have to be changed about once every five years, is in the order of C30 per year for one operating-theatre. The cost of infection of even one patient is anything up to ten times this (E300) apart from the hazard of pain and death. If these facts are so, the risk of filtering down to only 5 microns seems hardly worth taking. 2.
Blowers, R., Crew, B. J. Hyg., Camb. 1960, 58, 427
1170 Recirculation It can be calculated that by the introduction of 75% recirculation of the theatre-suite air (excluding the sterilisingroom) the size of refrigeration plant is a third of that required for 20 air changes with 100% fresh air. By provision of additional high-quality filters in the recirculated air ducts, dust-free and sterile air can be supplied to the theatre area. The capital saving on the refrigeration plant will more than pay for the high-quality air filters. The saving on the heating and cooling requirements of a two-theatre suite could be in the region of E500 a year. Thus, such a system would save E300 a year, and in addition to this there is no reason why the number of air changes in the operating-room should not be stepped up to 40 or 50 per hour, thus achieving a far higher standard of air sterility without upsetting the balance of air pressures. It is also interesting to note that the total resistance to air flow across the high-quality filters need be only in the order of 0-2 in. w.g. (total).
These are by no means all the points that we think further discussion or research, and, while in many ways the standards laid down are generally higher than those previously recognised, the emphasis appears to be on saving money on ventilation plant, rather than saving far more money by reducing to a minimum the possibility of infection by airborne particles. There may be a case for more careful consideration before such an authoritative report is put out. For instance, it seems particularly important, in view of the large hospital programme now under way, that the widest possible authorities should be consulted and the findings carefully assessed before being given as a guide to the professions concerned. P. B. D. SUTHERLAND J. E. FIRMAN.
require
SURVIVAL IN AIR AFTER BREATHING FLUID SIR,-Adult mice1 and rats2 have been kept alive for hours submerged and breathing a balanced saline solution containing a sufficient amount of dissolved oxygen. Attempts to resuscitate the animals, however, remained unsuccessful. Clearly if applied in man, as in the fcetal incubator suggested by Goodlin,3the person must survive after returning into the atmosphere, and preferably without residual damage. This now seems possible since submerged dogs have been made to breathe an isotonic salt solution for seven to twenty minutes, and the animals afterwards lived and breathed in air again, being apparently
quite healthy. The investigation was done in a pressure-chamber filled with air at a tension of four atmospheres absolute to permit intravenous administration of adequate amounts of oxygen,4 as well as to promote rapid absorption of trapped nitrogen from the airspaces of the submerged animals. Adult anxsthetised and intubated dogs were submerged in a bath containing a 0-9% saline solution at body temperature (32-35°C in the anaesthetised animals, as determined rectally). While submerged, the dogs received oxygen injected through a catheter into the inferior vena cava. Judged by the jets of liquid exhaled regularly through the endotracheal cannula fluid breathing occurred spontaneously and quite vigorously. Fluid breathing was terminated by connecting a hose with the endobronchial cannula and draining as much liquid as possible from the lungs. The dogs were then quickly removed from the bath and the intravenous oxygen insufflation was discontinued. The 1. Kylstra, J. A., Tissing, M. O., van der Maën, A. Trans. Amer. Soc.
lungs were inflated several times with oxygen and, after a few minutes, the dogs resumed breathing spontaneously. They were given oxygen to breathe throughout the period of chamber
they had
A full report of these
be
given elsewhere.
Holland.
J. A. KYLSTRA.
A SPINAL BRIDGE
SIR,-Mr. Turgill (Nov. 17) states that a new spinal bridge developed in Hungary is now being used in this country. Might I point out that the method of using a relaxed extension, in order to increase the range of extension of the spine in the stiff back of middle age, has been in use for years in this country and was described in 1958.1 My technique with special padded blocks has advantages, for these are graduated in height, so that strain can be avoided at first, and higher blocks used as the range of extension increases. This, however, is only part of the treatment. The patient must also practise active extension exercises and learn to stretch, but the popular extension exercises carried out in the prone position should be avoided. The rationale of the treatment was discussed2 in The Lancet. W. H. GERVIS. W. H. GERVIS. Tunbridge Wells. CANCER OF THE VULVA SIR,-Had you read the article3 to which you refer in your annotation of Nov. 17 (without, incidentally, including the name of my co-author and pathologist colleague, Dr. A. S. Woodcock) you could hardly have concluded that my view is that " leucoplakia " is not a precursor of squamous-cell carginoma of the vulva. Lest the misrepresentation does a disservice to your readers and
their patients, it seems important to restate what the article in question explains quite clearly. Our views are based not on a clinical impression, as you suggest, but on: (a) a prolonged personal follow-up of 103 women suffering from a chronic vulval dystrophy which, in most cases and by most clinicians, would have been diagnosed as leucoplakia; and (b) the findings in all the other published prospective studies of vulval skin diseases in relation to the subsequent development of cancer.4-7 As a result of such evidence, which is all that is available other than retrospective assumptions on which the traditional opinion was first rooted, the conclusions are:
(i) When leucoplakia is diagnosed on the histological finding of disorderly basal cell hyperplasia, and not on the macroscopic appearance of the skin, the condition clearly carries a real risk of the subsequent development of cancer. (ii) Leucoplakia (or lichen sclerosus) diagnosed by the clinician on naked-eye appearances shows variable and nonspecific histological features. (iii) If all vulvas described as leucoplakic on clinical grounds are subjected to biopsy, approximately 5% are found to be cancerous at the outset. And the malignant change is then often primary and not secondary. (iv) Of the remainder, approximately 5% will become malignant during the next 3-25 years, but this complication occurs only when the original biopsy shows a clear threat of
2.
artif. intern. Organs, 1962, 8, 378. Pegg, J., Horner, T., Wahrenbrock, E. Physiologist, August, 1962,
3. 4.
p. 194. Goodlin, Singh, I.
6. 7.
137, 318.
experiments will
Applied Physiology Division, Department of Physiology, University of Leiden,
1. 2. 3. 4. 5.
R. C. Lancet, 1962, i, 1356. Arch. int. Pharmacodyn. 1962,
decompression and intermittently thereafter until sufficiently from the anaesthesia.
recovered
Gervis, W. H. Orthopaedics in General Practice. London, 1958. Gervis, W. H. Lancet, 1961, i, 1353. Jeffcoate, T. N. A., Woodcock, A. S. Brit. med. J. 1961, ii, 127. Hunt, E. Diseases affecting the Vulva. London, 1954. Langley, I. I., Hertig, A. T., Smith, G. van S. Amer. J. Obstet. Gynec. 1951, 62, 167. Böttger, H., Dittmann, E., Geburtsh. u. Frauenheilk, 1957, 17, 1097. McAdams, A. J., Kistner, R. W. Cancer, 1958, 11, 740.
itself of its normal output of carbon dioxide despite the lowered partial pressure of carbon dioxide, and it can do so only
of double-ended autoclaves with one end accessible the sink room and the other only from the zone C.
by some adjustment in the distribution and flow of gas in the lungs, whether by a response of a respiratory centre to a high bicarbonate level, or by some other mechanism.
Air Changes Dr. Blowers 2 has previously shown that the background count of bacteria is reduced as the number of air changes rises. It appears, therefore, that far cleaner air would be achieved if the minimum number of changes in the operating-room and sterile work room were at least 20 per hour and in all other rooms within the suite were at least 10 per hour.
Carbohydrate metabolism produces equal quantities of hydrogen and bicarbonate ions. If too much of the hydrogen ion leaks through the kidneys, some bicarbonate must be stranded; and no amount of breathholding short of anoxia will prevent the consequent high concentration of bicarbonate, raised pH and lowered pCÛ2’ Hospital for Sick Children, London, W.C.1.
T. H. HUGHES-DAVIES.
OPERATING-THEATRES
SiR,—The report to the Medical Research Council (Nov. 10, p. 945) is a very thorough survey of problems associated with the ventilation of operating-room suites, but the inadequacy and vagueness of some of the conclusions show that a considerable amount of research has still to be done before definite recommendations can be given to architects and engineers in the form of a typical specification. Would it not have been wiser for the committee to have integrated their findings with those of the hospital engineering research unit at Glasgow and also to have tapped the wealth of information, about air filtration and bacteria, that is available at the War Department’s Establishments at Porton ? And made reference to the recent official American publication1 compiled by the U.S. Department of Health, Education and Welfare and the Department of U.S. Army Chemical Corps ? The following observations are submitted not as conclusions but as points of discussion: Position of the Operating-suite It is agreed that " stack effect " will cause airborne particles to rise to the top floor, but good architecture and ventilating design can readily prevent contamination of top-floor operating-suites. The importance of having space to house ventilation ducts, piped services, fans, filters, &c., cannot be over-emphasised. Operating-suites on lower floors restrict the space available for services, maintenance, alterations, and additions, so unless funds are available to provide a very preferable to adequate basement or service area, it appears " service floor ". use the top floor with a roof space to use as a Careful design can deal with noise and solar heat.
Arrangement of Rooms and their Ventilation The recommended zoning arrangement is in principle very satisfactory-especially the provision of airlocks ". But in the detailed design would it not be desirable to recommend that the changing-rooms be divided into " dirty " and clean areas, whereby dirty clothes are removed in the dirty area, the staff then wash or shower before entering the clean area, to don the sterile garments ? The air pressure in the "
"
"
"
"
"
"
"
"
clean
area
would of
course
be above that of the
dirty
area.
Sterilising-room In view of the dissipation of heat in the sterilising-room and the resultant convection currents which cause air transference to adjacent rooms, it seems that a recommendation should be made to house the autoclaves in a room, within zones B or C but separated from the operating-room by a ventilated lobby, and to provide the sterilising-room with about 30 air changes per hour of dust-free sterile air, from its own plenum ventilation plant. By a method of this sort, the ambient temperature of the sterilising-room can be maintained at about that of the communicating corridor or lobby and therefore undesirable air transference reduced. More consideration could have been given to the provision 1. Air Filtration of Microbial Particles. U.S. Education and Welfare Department of U.S.
June, 1962.
Department of Health Army Chemical Corps.
only from
Air Pressure It seems that what to do with the air discharged from the various rooms has not been seriously considered. Both the methods recommended have hazards from the bacteriological viewpoint. Firstly, the report stated that the exhaust apertures can discharge into a common duct. The hazard here is that the resistance to air-flow in the duct would vary as the different doors in the suite were used; this could cause a back pressure in the common duct that might result in air from a bacteriologically dirty duct or room flowing into a sterile room and general disturbances to the design. The other suggestion is " to reduce the total air volume of ventilating air, and the number of balanced flaps required, by allowing the air to pass from one zone into an adjacent part of the neighbouring lower pressure zone ". Surely this must be wrong; even with clean operations the air passing from the operating-room must be classed as dirty ", but when a dirty operation is carried out it is known that the air can become very heavily contaminated with pathogenic organisms. Can it be prudent to purposely pass this air into the corridor or the changing-room where the sterile clothes are stored ? The stated relative working pressures are lower than thought desirable. The pressure difference between clean rooms and corridors in pharmaceutical laboratories, &c., is frequently 0-1 in. water gauge (w.g.) and more. Why therefore are differences of 0-02 in. w.g. recommended ? In practice, such low pressures are difficult to maintain; minimum pressure differences of 0-1 in. w.g. should be sought, and inclined gauges 0-0-5 in. w.g. (type 504, Airflow Developments Ltd.) should be fitted to indicate pressure differences. "
Air Filtration It is stated that " filtration of the input air down to 5 microns is bacteriologically adequate ". Is this in fact beyond dispute ? To achieve clean and sterile air conditions in laboratory animal houses, pharmaceutical laboratories, and various other clean areas, it has been found necessary to install filtration plant that virtually removes all particles down to the size of less than 0-01 microns. The filters recommended in the report are used normally as pre-filters for the above applications or as the final filters for normal commercial filter applications. These filters permit the transfer of many hundreds or even a thousand times more dust particles, each of which possibly may become a carrier of germs liberated by the patient or theatre staff. From the report it can be assumed that germs or agglomeration of germs of less than 5 microns will not cause infection ? It is understood there are a number of modern operatingtheatres where the 5-micron standard of filters were installed and have not proved satisfactory, resulting in the installation of additional high-grade terminal filters’ (E. N. Mackley Ltd., Gateshead). Apart from supplying sterile air into the theatre and ancillary rooms the terminal filters prevent convection currents causing the air ducts to become contaminated if the ventilation plant fails or is shut down. They also will remove bacteria that might breed in the air washers, &c. The maintenance cost of these terminal filters, which have to be changed about once every five years, is in the order of C30 per year for one operating-theatre. The cost of infection of even one patient is anything up to ten times this (E300) apart from the hazard of pain and death. If these facts are so, the risk of filtering down to only 5 microns seems hardly worth taking. 2.
Blowers, R., Crew, B. J. Hyg., Camb. 1960, 58, 427
1170 Recirculation It can be calculated that by the introduction of 75% recirculation of the theatre-suite air (excluding the sterilisingroom) the size of refrigeration plant is a third of that required for 20 air changes with 100% fresh air. By provision of additional high-quality filters in the recirculated air ducts, dust-free and sterile air can be supplied to the theatre area. The capital saving on the refrigeration plant will more than pay for the high-quality air filters. The saving on the heating and cooling requirements of a two-theatre suite could be in the region of E500 a year. Thus, such a system would save E300 a year, and in addition to this there is no reason why the number of air changes in the operating-room should not be stepped up to 40 or 50 per hour, thus achieving a far higher standard of air sterility without upsetting the balance of air pressures. It is also interesting to note that the total resistance to air flow across the high-quality filters need be only in the order of 0-2 in. w.g. (total).
These are by no means all the points that we think further discussion or research, and, while in many ways the standards laid down are generally higher than those previously recognised, the emphasis appears to be on saving money on ventilation plant, rather than saving far more money by reducing to a minimum the possibility of infection by airborne particles. There may be a case for more careful consideration before such an authoritative report is put out. For instance, it seems particularly important, in view of the large hospital programme now under way, that the widest possible authorities should be consulted and the findings carefully assessed before being given as a guide to the professions concerned. P. B. D. SUTHERLAND J. E. FIRMAN.
require
SURVIVAL IN AIR AFTER BREATHING FLUID SIR,-Adult mice1 and rats2 have been kept alive for hours submerged and breathing a balanced saline solution containing a sufficient amount of dissolved oxygen. Attempts to resuscitate the animals, however, remained unsuccessful. Clearly if applied in man, as in the fcetal incubator suggested by Goodlin,3the person must survive after returning into the atmosphere, and preferably without residual damage. This now seems possible since submerged dogs have been made to breathe an isotonic salt solution for seven to twenty minutes, and the animals afterwards lived and breathed in air again, being apparently
quite healthy. The investigation was done in a pressure-chamber filled with air at a tension of four atmospheres absolute to permit intravenous administration of adequate amounts of oxygen,4 as well as to promote rapid absorption of trapped nitrogen from the airspaces of the submerged animals. Adult anxsthetised and intubated dogs were submerged in a bath containing a 0-9% saline solution at body temperature (32-35°C in the anaesthetised animals, as determined rectally). While submerged, the dogs received oxygen injected through a catheter into the inferior vena cava. Judged by the jets of liquid exhaled regularly through the endotracheal cannula fluid breathing occurred spontaneously and quite vigorously. Fluid breathing was terminated by connecting a hose with the endobronchial cannula and draining as much liquid as possible from the lungs. The dogs were then quickly removed from the bath and the intravenous oxygen insufflation was discontinued. The 1. Kylstra, J. A., Tissing, M. O., van der Maën, A. Trans. Amer. Soc.
lungs were inflated several times with oxygen and, after a few minutes, the dogs resumed breathing spontaneously. They were given oxygen to breathe throughout the period of chamber
they had
A full report of these
be
given elsewhere.
Holland.
J. A. KYLSTRA.
A SPINAL BRIDGE
SIR,-Mr. Turgill (Nov. 17) states that a new spinal bridge developed in Hungary is now being used in this country. Might I point out that the method of using a relaxed extension, in order to increase the range of extension of the spine in the stiff back of middle age, has been in use for years in this country and was described in 1958.1 My technique with special padded blocks has advantages, for these are graduated in height, so that strain can be avoided at first, and higher blocks used as the range of extension increases. This, however, is only part of the treatment. The patient must also practise active extension exercises and learn to stretch, but the popular extension exercises carried out in the prone position should be avoided. The rationale of the treatment was discussed2 in The Lancet. W. H. GERVIS. W. H. GERVIS. Tunbridge Wells. CANCER OF THE VULVA SIR,-Had you read the article3 to which you refer in your annotation of Nov. 17 (without, incidentally, including the name of my co-author and pathologist colleague, Dr. A. S. Woodcock) you could hardly have concluded that my view is that " leucoplakia " is not a precursor of squamous-cell carginoma of the vulva. Lest the misrepresentation does a disservice to your readers and
their patients, it seems important to restate what the article in question explains quite clearly. Our views are based not on a clinical impression, as you suggest, but on: (a) a prolonged personal follow-up of 103 women suffering from a chronic vulval dystrophy which, in most cases and by most clinicians, would have been diagnosed as leucoplakia; and (b) the findings in all the other published prospective studies of vulval skin diseases in relation to the subsequent development of cancer.4-7 As a result of such evidence, which is all that is available other than retrospective assumptions on which the traditional opinion was first rooted, the conclusions are:
(i) When leucoplakia is diagnosed on the histological finding of disorderly basal cell hyperplasia, and not on the macroscopic appearance of the skin, the condition clearly carries a real risk of the subsequent development of cancer. (ii) Leucoplakia (or lichen sclerosus) diagnosed by the clinician on naked-eye appearances shows variable and nonspecific histological features. (iii) If all vulvas described as leucoplakic on clinical grounds are subjected to biopsy, approximately 5% are found to be cancerous at the outset. And the malignant change is then often primary and not secondary. (iv) Of the remainder, approximately 5% will become malignant during the next 3-25 years, but this complication occurs only when the original biopsy shows a clear threat of
2.
artif. intern. Organs, 1962, 8, 378. Pegg, J., Horner, T., Wahrenbrock, E. Physiologist, August, 1962,
3. 4.
p. 194. Goodlin, Singh, I.
6. 7.
137, 318.
experiments will
Applied Physiology Division, Department of Physiology, University of Leiden,
1. 2. 3. 4. 5.
R. C. Lancet, 1962, i, 1356. Arch. int. Pharmacodyn. 1962,
decompression and intermittently thereafter until sufficiently from the anaesthesia.
recovered
Gervis, W. H. Orthopaedics in General Practice. London, 1958. Gervis, W. H. Lancet, 1961, i, 1353. Jeffcoate, T. N. A., Woodcock, A. S. Brit. med. J. 1961, ii, 127. Hunt, E. Diseases affecting the Vulva. London, 1954. Langley, I. I., Hertig, A. T., Smith, G. van S. Amer. J. Obstet. Gynec. 1951, 62, 167. Böttger, H., Dittmann, E., Geburtsh. u. Frauenheilk, 1957, 17, 1097. McAdams, A. J., Kistner, R. W. Cancer, 1958, 11, 740.