ECONOMIC PREREQUISITES FOR APPLYING IN HEALTH INSTITUTIONS STEL ELECTROCHEMICAL DEVICES FOR SYNTHESIS OF WASHING, DISINFECTANT AND STERILIZING SOLUTIONS

ECONOMIC PREREQUISITES FOR APPLYING IN HEALTH INSTITUTIONS STEL ELECTROCHEMICAL DEVICES FOR SYNTHESIS OF WASHING, DISINFECTANT AND STERILIZING SOLUTIONS

V.M. Bakhir, V.I. Vtorenko, V.I. Prilutsky, N.Yu. Shomovskaya

RF Academy of Medical Technical Sciences

A tendency towards higher incidence of communicable diseases in Russia observed in the early 1990s is still here today. A need arises to produce and apply antimicrobial agents as well as radically improve epidemiological service. The concept of nosocomial infections’ prevention (NI) [1] aimed at combating spread of infections in health institutions estimates minimal economic damage caused by NI of 5 billion rubles (in 1999 prices). Actual economic damage nationwide is much greater. The concept of NI prevention envisages a number of measures including “developing optimal conditions and modes of application of new disinfection equipment” as well as “developing a system of economic measures stimulating domestic manufacturers of up-to date disinfectant agents”, a more thorough economic analysis of sanitary and epidemiologic service efficiency taking into account expenditures on disinfection and sterilization. Economic analysis in conditions of Russian health system reforms is of particular importance considering lack of material resources.

It is clear that if health establishments are viewed as high epidemiological risk objects, the corresponding services should be transformed into disinfection rooms or departments with a number of specific functions, actually, a kind of small enterprises producing working solutions of detergent and antimicrobial agents. The requirement for antimicrobial agents in in-patient health establishments is 2.5-2.8 l per bed a day. The total number of hospital beds in the country being 108 per 10,000 people (1,566,000 beds) [2], the annual demand for working solutions of antimicrobial and washing agents is approximately 1.4-1.6 million tons a year (for in-patient facilities alone). Distribution of cost values of 1 liter of disinfectant working solutions is given in Table 1.

Table 1. Distribution of prices for 1 liter of disinfectant working solutions (rub/l) having declared market value

P, rub.

0.2

0.3-0.5

0.6-1.5

1.6-3.0

3.0-6.0

6.0-10.0

> 10

C

1

2

3

4

5

6

7

N

3

5

14

10

19

11

9

Note: P – price of 1 liter of working solution, C – category of cost value, N – number of included disinfectant names (brands).

According to the data presented in Table 1, an average cost of 1 liter of disinfectant working solution is 5-6 rubles. According to the findings of St. Petersburg sanitary and epidemiological services, among routinely used antimicrobial agents there prevail “Chloramin” (4.5 rub/l), “Lyzopharmin-300” (5 rub/l), “Aminalol” (1.5 rub/l), “Septodor” (from 1 to 66 rub/l depending on its concentration) as well as some other expensive preparations. The above data suggest that the 5 ruble average cost of 1 liter of disinfectant working solution makes total expenditures on antimicrobial agents in all Russian in-patient facilities equal to » 7-8 billion rubles, which exceeds losses due to NI. Under such conditions, undoubtedly critical NI control becomes economically unsound. To eliminate this paradox it is necessary to reduce the price of disinfectants while maintaining their efficiency and relative safety for man and environment. Estimated commercial price of 1 liter of antimicrobial and/or detergent working solution equivalent to NI losses is less or equal to » 3 rub/l. This calculation requires observance of the following inequality:

(1)

where С – cost of 1 liter of disinfectant working solution, rub/l;
Y - sum of NI losses (in this case it is 5 billion rubles);
Q – total required amount of disinfectant working solutions used in health facilities (» 1.5 billion liters per year);

Conditions of health establishments with high risk of NI demand decontaminating agents efficient not only against vegetative bacterial forms (non-specific flora), but also viruses, fungi, Candida species, spores. The problems with NI and general aggravation of epidemiological situation are known to be due to increased quantity of microorganism strains resistant to disinfectants and antiseptics, which are to be applied in solutions in increased concentrations. The cost of such solutions becomes higher. Simultaneously, a certain part of antimicrobial agents, to which there exist resistant microorganism strains, is applied actually in vain being only “partially efficient”. A special notion can be introduced for antimicrobial agents – “decontamination efficiency cost index” (IC), which can be expressed in the following manner:

(2)

where R - share of moderately sensitive and resistant strains, in shares from 1.0 ~ 100% resistance.

For instance, according to [3], the number of Staphilococcus Aureus, enterobacteria and non-fermenting gram-negative bacteria strains resistant to “Chloramin-B” (tests on Petri-dishes with meat-peptone agar, i.e. under elevated organic load) is 19.6% (0.196 unit fractions), moderately sensitive – 40.7% (0.407), sensitive – 39.7% (0.397). Correspondingly: 1 - R = 1 – (0.196 + 0.407) = 0.397; IC = 1/0.397 = 2.52. It means that the real cost of microflora decontamination in these conditions rises by approximately 2.5 times to 11 rub/l (4.5 rub/l ´ 2.5). The physical meaning of index IС here means that in addition to expenditures on Chloramin-B there are necessary expenditures on eradicating resistant flora, and that, together with previous expenditures, rise approximately 2.5-fold if agents of the same cost are used. Expenditure increase when using disinfectant to which resistant flora has been developed in real life can be higher or lower than the estimated value. Therefore, index IC is only a reference. Thus, if an agent is not capable of eradicating NI in a particular facility (R of resistant strain = 1), IC ® ¥ , which signifies “infinite” increase of expenditures on NI elimination given the continued use of ineffective agents.

The cost of “Septodor” used for suppressing viral and specific bacterial flora varies between 4.4 and 11 rubles per 1 liter of working solution, on the average about 7-8 rub/l; 68.5% of investigated strains [3] are sensitive to this preparation. In this case, IС = 1/0.685 » 1.5. Total expenditures on quality disinfection using other agents of similar cost will be equivalent to approx. 12-14 rub/l of working solution. Therefore, in terms of cost efficiency “Septodor” is inferior to “Chloramin B”, and in both cases additional resources are necessary as well as search for new preparations capable of suppressing resistant microflora.

The findings in source [3] should not be overemphasized for the following reasons: the tests were carried out in conditions of considerable organic load (nutrient medium on Petri dish), far from all microbial strains were tested, and there were no tests of viral and fungal pathogens. These examples show that an agent’s novelty and the results of laboratory tests are not fully informative as to its efficiency. Exhaustive information including economic impact is contained only in data received in the process of controlled employment. According to St. Petersburg sanitation and epidemiological service, “Septodor” is applied in 16 health establishments, “Chloramin-B” - in 41. This is probably due to financing matters.

Since antimicrobial agents are needed not only in in-patient health establishments but also in out-patient clinics, in veterinary practice, agriculture, food industry, at home, in transport vehicles, water supply and sewage decontamination systems etc., the demand for disinfectants greatly increases and can achieve dozens of million tons of working solutions a year, and correspondingly, expenditures can approach 1011 rub/year. Therefore, the problem of making disinfectants cheaper becomes critical. Risk of appearance of strains resistant to different antimicrobial agents strongly depends on chemical stability of those agents and on accumulation in the environment of their degradation products, to which microorganisms readily adapt themselves. Antimicrobial substances containing active components (AC), such as quaternary ammonium compounds, aldehydes, cationic surface active agents (SAA) and alcohols are based on combination of substances, stable by nature, or forming stable products after transformation, which maintain initial AC characteristics for a lengthy period of time. That results in microorganism ability to adapt themselves to the above-indicated stable substances and thus to increased number of resistant strains. Therefore, in conformity with the formula (2) actual cost of decontamination will continuously grow, as suppression of resistant microflora will demand new agents and establishment of additional microbiological services for testing flora sensitivity in every health establishment. Microbiological analyses’ cost will be added to total expenditures on acquisition of a wide scope of disinfectants. At the same time, the total expenses can even now take up a considerable portion of the national budget.

Routinely used chlorine-containing chemicals produced today under dozens of names contain various compounds (including chlorine organic ones) but practically in all cases the AC of those chemicals is either hypochlorous acid resulting from reactions with a neutral organic substrate (рН » 7), or molecular chlorine generated in acid media (рН < 5) [4]. Hypochlorous acid and molecular chlorine are chemically unstable (meta-stable). Hypochlorous acid decomposes into chloride ion (Cl- ) and active oxygen. Chloride ion is biologically inert and does not affect the formation of resistant microbial strains. Active oxygen is meta-stable and is not accumulated in the environment, which makes microbial selection for adaptation to such agent nearly impossible. For aerobic forms its action from the point of view of adaptation is not taken into consideration because “aerobes” require common molecular oxygen (О2). Molecular oxygen is sublimated into atmosphere and cannot accumulate in the area of microbial reproduction. Molecular chlorine behaves similarly (Cl2). Owing to the above meta-stability factors, chlorine agents of the old generation (beginning with Semmelweis’s “chlorine water”) have efficiently helped combat infections for almost a century and a half. At present, meta-stable chemicals based on peroxide compounds as AC have proved to be efficient disinfectants and antiseptics [5, 6, 7]. Among the latter, the most well known one is hydrogen peroxide. According to the source [3], only 3.1% of strains from 226 tested ones are absolutely resistant to hydrogen peroxide. The cost of this agent (according to data obtained from Moscow pharmacies) is 34 rub/l. Nevertheless, the preparation is one of the most frequently used in clinics.

Recently, a new generation of electrochemically synthesized biocidal chlorine-containing and oxygen-containing solutions have been developed and introduced into practice. They include: sodium hypochlorite produced in static electrolyzers, and ANK neutral anolyte (рН 6.8-7.8) generated in STEL devices (manufactured by ОАО NPО EKRAN, Moscow) fitted with a flow-through membrane electrochemical reactor based on FEM modules (FEM-3 in the last generation), using electrochemical activation technology (ECA). At pH values close to neutral ANK anolyte contains as AC hypochlorous acid (HClO), hypochlorite ion (ClO- ), ozone, hydrogen peroxide, other peroxide type meta-stable compounds including active oxygen (8). In foreign literature such AC compositions produced electrochemically are called “mixed oxidants” (7). Meta-stability is a distinguishing feature of ECA solutions. ANK anolyte leaves no dirt, is not accumulated in the body and the environment, and has a detergent effect. AC content in ANK anolyte is hundredth shares of a whole weight percent (0.02-0.09 %), being much lower than “active chlorine” concentration in chlorine-containing antiseptics of old generation (chloramin, chlorinated lime and so on). As required, ANK anolyte AC amount can be adjusted within wider limits. Low concentrations of “active chlorine” in anolyte considerably decrease chances of toxic halogen-containing compound (HCC) formation in conformity with a well-known chemical law of mass action. ANK anolyte either has no odor of oxidants, or it is no more intensive than the odor of chlorinated water in a swimming pool, and is not smelled at a distance of 1-2 m from an open tank with the solution. Large quantities of ANK anolyte can be prepared on site, which is considered to be an advantage.

According to the findings of the Research Institute of Preventive Toxicology and Disinfection (9) ANK-type anolytes synthesized in STEL devices, with “active chlorine” content of 0.02-0.09% (200-900 mg/l ¸ 3 – 12.5 mmol/l) belong to toxicity Class IV. The ANK anolyte ACs are attributed to the category of eubiotics – substances produced by the body in the process of phagocytosis. ANK anolyte is well compatible with body tissues and can be used in septic wound treatment causing no irritation of granulation tissue (10). ANK anolyte modifications have been developed producing no corrosive action on metal objects during cold sterilization. Correspondingly, ANK anolyte scope of action extends to nearly all areas of liquid disinfectants’ use in medicine and other industrial and economic spheres.

There are no data on the presence of microflora resistant to ANK anolyte. In practice, it has been proved by the results of controlled STEL devices’ operation at the Moscow Clinical Hospitals 15 and 52. Today these clinics use ANK anolyte to satisfy more than 90 % of their requirements for disinfectants. The number of improper bacterial samples has decreased about 10-fold. Before ANK anolyte application, hepatitis B incidence in the above-mentioned hospitals was 0.45-0.50 %. After the beginning of anolyte use the figure decreased to 0.06-0.08 % (6-7 times) (11). If there had appeared microflora resistant to anolyte, such results could have never been possible. Similar information came from a hospital in Rostov-on-Don. (12). In St. Petersburg, ANK anolyte is used in 25 hospitals. In Samara region, about 100 various device modifications are operating (А.G.Ryabov, ООО “Clean world”): of them, 75% are models with 40 and 80-liter capacity, 20% are devices with 20-l/h capacity; 5% are devices of higher capacity (120-250 liters per hour). Most devices are used in hospitals in Samara (over 50%), Togliatti, Novokuibyshevsk, Chapayevsk (about 30%) and in central hospitals of rural areas (20%). STEL devices operate in Ulyanovsk hospitals (Central Clinical Hospital data), in the towns of Budyonnovsk and Yelets in the Lipetsk region, in the health establishments in Tver, Ivanovo, Voronezh, Novosibirsk, Belgorod regions; in Vitebsk region (Belarus, the data of Health Department of the Vitebsk region Executive Committee for 2003), in Khlebnikovo Military Hospital (13). In Moscow, ANK anolyte has been used for a number of years in City Clinical Hospital 40, War Veterans’ Hospital 3, Military Medicine Institute, CITO (Central Institute for Traumatology and Orthopedics), and a number of other facilities.

STEL devices are used in the USA, Mexico, South Korea, South African Republic, Lithuania, the Ukraine, in Central Asian republics, in South-Eastern Asia and other countries. ECA disinfectants are applied in Japan.

There are data on STELs’ good self-recoupment in Russia – approximately 1.5-3 months, depending on the operating regime and taking into account capital investments, nonrecurring and operating costs for anolyte production. Competitiveness of ANK anolyte and STEL devices on home and foreign markets is evident. Of crucial importance here is a low cost of ANK anolyte production formed from nonrecurring costs of STEL device purchase and installation, and of operating costs related to consumption of source substances, power, device maintenance, end-product control, running the premises, staff salary etc.

ANK anolyte cost calculation per 1 liter of working solution in conditions of the Russian Federation.

Expenditure pattern for anolyte production in a STEL device by the example of STEL-10Н-120-01 with 70-75 l/h anolyte output.

  1. Purchase of the device » 30,000 rub. (in 2003 prices) – nonrecurring costs with allowance made for working place setting up;
  2. Salt costs: no more than 5 g/l per year (252 working days, 5.5 hours a day, salt price: 3.5 rub/kg) – 1700-1800 rub/year;
  3. Power consumption: 0.00875 kW/l/h, 1.62 rub/kW/h ~ 1400-1500 rub/year;
  4. Purchase of hydrochloric acid to wash the device (0.07 l/day, 30 rub/l) – 530 rub/year.
  5. Depreciation cost for item 1 on the basis of the device’s 5-year warranty period – 6,000 rub.

The maximum sum of expenditures for items 2-5 is » 9,800 rub/year spent on production of » 100,000 liters of anolyte, which is equivalent to » 0.1 rub/l.

Economic situation corresponding to items 1-5 is equivalent to one-time interest-free crediting under the item “disinfectant purchase” of 30,000 rubles for 5 years. At 10% annual inflation that ensures a profit of » 2,800 rub/year.

Expenditures for ANK anolyte production decrease due to increased solution output during a shift using devices of a larger nominal size, two-shift operation and synthesis of anolyte with lower mineralization level (up to 1 g/l of salt). Taking into consideration the above factors, the cost of producing 1 l of anolyte is 0.05-0.07 rub/l.

Maximum nominal size STEL device is designed to produce 700 l/h being able to operate during three shifts for 15 hours a day. The device capacity is 2 kW/h. With adequate technical maintenance, the device provides anolyte with specific oxidant content 1000 mg/l and mineralization 2.2 g/l. The cost of producing one liter of such anolyte in conditions of one-shift operation is 0.19 rub/l, three-shift operation – 0.07-0.08 rub/l. One liter of initial anolyte can produce 2 or 3 liters of working solution costing 0.02-0.01 rub/l (depending on operation regime). According to calculations made in Samara, the production cost of 1 l of ANK anolyte is 0.12 rub/l. This calculation does not take into account cost of water used for preparation of working solutions of disinfectants of any brand.

Low cost of ANK anolyte production, absence of resistance to it, a wide scope of action and good biocompatibility make anolyte and its modifications promising disinfectants and antiseptics in terms of its main functional parameters (antimicrobial and detergent action) as well as cost effectiveness. The gap between anolyte cost price and the rate of its application cost-effectiveness (see expression [1]) is no larger than 2.9 rub/l. On-site anolyte production (in disinfection departments, directly in therapeutic units or utility rooms) will require some additional expenditures (60 l holding tanks, supply system) and training of personnel operating STEL devices (probably the establishment of a new position), but will eliminate spending on the following expenditure items:

  • Warehouses for long-term storage will be substituted by a few holding tanks, or none at all;
  • No emergency and reserve preparation stocks are needed;
  • There is no need to purchase imported agents and to transport them for considerable distances (inside the Russian Federation or from abroad; from the store to a hospital);
  • Risk of allergic and toxic effects is greatly reduced;
  • Need for a huge chemical industrial complex with chemical production capacity of about hundreds of thousand tons a year from the stage of mineral extraction to processing and production of concentrated disinfectants, from which working solutions are made, dramatically decreases;
  • General toxicological pressure on ecosystem becomes lower.

If taking into consideration all sorts of expenditures the final price of 1 l of anolyte is 1.5 rubles, corresponding per capita spending in Russia will fall by approximately 3,7 times, which is equivalent to saving no less than $ 1.4 per head ~ $ 200 million for the whole population. In fact, with regard to requirements in other fields the saving will be dozens of times greater. Therefore, ECA disinfection technologies can considerably reduce the State budget expenditures.

References

  1. V.I. Pokrovsky. A concept of nosocomial infections’ prevention. Moscow. RAMN. 1999.
  2. (Summary). Health of Russian population and health facilities’ activity in 2001. MZ RF. Department of establishment and development of community-oriented medical care. Section of statistics and informatics. Item. 2.11. Article. 121. M. 2002.
  3. V.A. Bondarev, G.B. Altayskaya, Z.A. Gorbunova. Organization of Lipetsk region disinfection and sterilization center work for evaluating disinfectant efficiency in regard to various microorganism species (J.) Dezinfektsionnoye delo, N 2, 1999, pp. 4-7.
  4. V.M. Bakhir, B.I. Leonov, S.А. Panicheva et al. (J.) Meditsinskiy alfavit, N 9, 2003, pp. 20-23.
  5. V.S. Kasatkin. General information on peroxides. Information letter. RGSKhA. Moscow. 12.09.2003. 7 pp.
  6. V.N. Sherasimov, Ye.А. Golov, I.V. Babich et al. Investigation of the mechanism of action of a new class of peroxide disinfectants – peroxide-hydrates. (J) Dezinfektsionnoye delo, N 1, 1999, pp. 14-18.
  7. Beth Hamm. Disinfection By-Product Reduction. Using On-Site Generation Mixed Oxidants in Groundwater Treatment. Company of Tetra Tech. Inc. Lexington. Kentucky. 2002.
  8. V.М. Bakhir, B.I. Leonov, S.А. Panicheva et al. Efficiency and safety of chemicals used for disinfection, pre-sterilization cleansing and sterilization. (J) Dezinfektsionnoye delo, N 1, 2003, pp. 29-35.
  9. In the book “Disinfectants”. P.1. Ed.1. Ed. by А.А. Monisov, M.G. Shandala.
  10. N.V. Loktionova et al. (CITO, Moscow). In the book “All-Russian Conference on Methods and Means of Sterilization and Disinfection in Medicine”, VNIIMT, Moscow, 1993, pp. 9-12.
  11. V.B. Rovinskaya, О.I. Sukhova. Case history of using electrochemically activated solutions in a multi-functional hospital. “Proceedings of the First International Symposium “Electrochemical activation in medicine, agriculture and industry”. M.: VNIII of Medical Engineering, 1997. – pp. 70-72.
  12. L.К. Brusova, V.I. Semilet, А.S. Sokolov, Ye.V. Moskalenko et al. Case history of using today’s disinfectants in health establishments in Rostov-on-Don (J) Dezinfektsionnoye delo, N 1, 2003, pp. 46-47.
  13. S.N. Mikhailov, V.V. Mistryukov, I.М. Chuyeva. Voyenno-meditsinskiy zhurnal, N 9, 1999. pp. 56-58.

Published in the journal Meditsinskiy alfavit, N 11, 2003, pp. 24-25, N 1, 2004, pp. 25-27.