*The paper based on research carried out within the doctoral dissertation defended by Piotr Pałaszkiewicz, MD at the Medical Faculty of Poznań University of Medical Sciences in 2009.

An increasingly high interest taken in the issues of risks associated with prolonged exposure of the medical personnel of operating rooms to inhalation anaesthetics led to the initiation of the first, extensive, national survey regarding ecological conditions of operating theatres in Poland. The survey was conducted at the Medical University of Poznań in 1996 [1]. The extent of contamination demonstrated was a good reason to carry out comprehensive studies involving more hospitals [1]. Recently, thanks to the efforts of research teams, several papers were published describing the conditions of operating room environment of some hospitals in Great Poland, the region of Lublin, Łódź and Wrocław [2, 3, 4, 5]. However, extensive epidemiological surveys covering several hundreds of Polish hospitals have not been carried out.

The available literature addressing the issues in question [6, 7, 8] documented the relations between the extent of contamination and increased frequency of known risk factors, mainly faulty technical infrastructure of operating rooms, lack of suitable anaesthetic devices or polluting methods of anaesthesia. The repetitiveness of those relations prompted us to estimate the extent of risks by analysing the known risk factors of operating room contamination with inhalation anaesthetics.

METHODS

In the period between 15.10.2006 – 31.01.2007, the survey questionnaire consisting of 35 questions, was sent to 484 hospitals and addressed by name to the heads of departments  of anaesthesiology and intensive therapy. The survey questions referred to infrastructure of operating rooms, characteristics of anaesthetic devices, and methods of anaesthesia. For the research purposes, hospitals were classified according to their referral levels (teaching, regional/specialist and county). To assess possible regional differences in ecological safety of operating rooms, the territory of Poland was divided into three regions: north-west, central and west (Table 1).

The data were statistically analysed. The Pearson χ 2 or Fisher-Freeman-Halton test was used for category data. Once the test result was significant, individual percentages were compared using the Gauss test. The ranked data were compared using the non-parametric Kruskal-Wallis test for many groups followed by the Dunn’s multiple range test. The level of significance was set at p<0.05.

RESULTS

Two hundred and seventy (55.8%) questionnaires were returned. Their data provided information about 1280 operating rooms from all regions of Poland (Table 2).

The highest percentage of operation rooms < 100 m3 was found in county hospitals. Moreover, compared to teaching and regional hospitals, county hospitals showed the lowest percentage of operating rooms equipped with air-conditioning and ventilation systems (Fig. 1).

The comparison of gas scavenging and compressed air systems available in operating rooms demonstrated the lowest deficits in teaching hospitals; the lowest availability of these devices was found in county hospitals. The systems of central N2O distribution were present in more than half of teaching hospitals; in the majority of operating rooms of county hospitals, N2O was supplied from cylinders (Fig. 2). Lack of ventilation and scavenging systems  was observed in every fifth operating room of county hospitals. The differences in technical infrastructure were statistically significant.

In county hospitals, almost half of anaesthetic machines were older than 10 years; 2/3 of them did not have devices for automated seal testing (the difference significant compared to higher-level hospitals). One in five operating rooms in county hospitals was not equipped with a capnograph; in almost 50% anaesthetic gas analysers were not available (the difference significant compared to teaching and regional hospitals). Moreover, anaesthetic ventilators were lacking in significantly higher number of operating rooms of county hospitals (Fig. 3). The comparison of answers to the question concerning the use of low and minimal flows of gases and inhalation anaesthetic vapours disclosed higher incidences of the application of such techniques in teaching and regional hospitals.

According to the answers concerning the use of TIVA, no significant differences were found between the types of hospitals. In lower referral level hospitals, the key barrier of more frequent use of TIVA were financial and equipment shortages; for the respondents from teaching hospitals, the barrier was related to their habitual use of other anaesthesia methods; however, the differences did not reach the threshold of significance.

The question about everyday testing of anaesthetic machines (leakage) was answered positively by 95% of respondents; 50% of respondents gave positive answers to the question regarding equipment testing before each anaesthesia.

The highest number of positive answers about possible discontinuation of N2O use until 2010 came from county hospitals – 73%, followed by regional – 64% and teaching hospitals – almost 60%. N2O as an anaesthetic was no longer used by 7% of respondents from regional hospitals, 3% - from teaching hospitals and 1.3 % – from county hospitals, although the differences were not significant.

DISCUSSION

For the reasons of ecological safety, the essential elements of operating room equipment are ventilation and scavenging systems.

The most effective ventilation system is air conditioning equipped with laminar flows with a suitable number of air exchanges per one hour. According to Krajewski and co-workers [2], an alternative to expensive air-conditioning systems is the use of efficient ventilation systems, provided that a suitable suction system of anaesthetic gases is available. Our findings suggest that 2/3 of operating rooms in county hospitals have no air-conditioning; half of them are not equipped with any ventilation systems and in over 40% – scavenging systems are lacking. The situation seems serious considering that almost 20% of operating rooms in county hospitals are not equipped with any ventilation and gas elimination systems.

The conditions in teaching and regional hospitals are better, yet some shortages were also observed. Compared with the data presented by Szulc and co-workers [5], some improvement has been observed. According to Szulc and co-workers, who assessed the extent of pollution of operating room air in two macro-regions of Poland in the years 2001-2003, 37.9% of operating rooms lacked any devices to clean air. Nowadays, general anaesthesia with inhalation anaesthetics in rooms deprived of ventilation or scavenging systems should not be performed.

Another element of technical infrastructure of operating rooms that may affect anaesthetic-related contamination is the distribution of nitrous oxide. Łukaszewski and colleagues [4] demonstrated higher air contamination with N2O in the operating rooms in which nitrous oxide cylinders were used. In the present study, markedly lower availability of central distribution of this anaesthetic was found in operating rooms of county hospitals compared to higher referral level institutions. Moreover, it should be stressed that wall gas-outlet sockets may also have leaks [4, 9, 10].

The factor determining the extent of contamination of operating rooms with inhalation anaesthetics is also its cubic capacity: in rooms with the capacity < 100 m3, the admissible concentrations of inhalation anaesthetics were found to be more exceeded [5]. The data from our respondents suggest that the capacity of over half of operating rooms in county hospitals was lower than 100 m3. In this respect, the situation in teaching and regional hospitals was better.

The use of air, by providing the respiratory mixture deprived of N2O, may indirectly reduce the operating room contamination with this anaesthetic; in cases of general intravenous anaesthesia, it may eliminate inhalation anaesthetics. The best situation is found in teaching hospitals. In regional hospitals, every forth operating room has no access to compressed air; in county hospitals – every third. Such findings indicate that lower referral level hospitals cannot limit the use of N2O or more frequently apply TIVA due to economic and technical barriers.

The leak of anaesthetic devices is one of the major reasons of operating room contamination with inhalation anaesthetics. The analysis of studies conducted in Poznań between 1996-1997 indicated lower levels of contamination in the operating rooms with the brand new anaesthetic machines [1]. The next survey involving two macro-regions of Poland demonstrated a significantly higher number of exceeded upper limits of anaesthetics in cases when the anaesthetic devices used were older than 10 years [5]. In Poland, following the wave of protests of the anaesthesiologists, the regulation regarding the equipment standards was brought into effect in 1998, which contributed to the replacement of anaesthetic devices or supplementation of their shortage. However, the data obtained for the purposes of the present study show that 33-45% of anaesthetic machines, depending on the hospital type, was older than 10 years.

For further comprehensive assessment of the anaesthetic equipment-related conditions of operating rooms, the availability of anaesthetic ventilators, capnographs and anaesthetic gas analyzers was evaluated. Their presence may indirectly result in decreased pollution by enabling the use of anaesthetic procedures with low and minimal gas flows. The deficits demonstrated were most commonly observed in hospitals of the lowest referral level. The design of 2/3 of anaesthetic machines in county hospitals do not allow automatic testing, which undoubtedly facilitates the detection of leaks. In hospitals of higher referral levels, such problems were found in half of the machines used. 

Even the best technical equipment may not be sufficient for effective protection of operating room staff against exposure to inhalation anaesthetics once any uncontrolled emission occurs due to underestimation or ignorance of the problem. The awareness of risks and proper management may improve the conditions of operating rooms, especially those with deficits in technical infrastructure. This is the easiest and cheapest measure to reduce contamination, as it does not require financial outlays.

The basic standards of anaesthesia safety include everyday checking of anaesthetic devices [11]. In the present survey, 95% of respondents confirmed everyday leakage testing of anaesthetic machines; however, it seems that a one-time seal test may be insufficient for effective prevention of pollution.

Appropriate anaesthetic techniques contribute to the reduction of operating room pollution with inhalation anaesthetics. One of them is the use of low and minimal flows of fresh gases [12]. Our findings suggest that this method of anaesthesia was significantly more commonly used in hospitals of higher referral levels. Lack of equipment in county hospitals was the likely reason of rarer use of such anaesthesia methods. The release of inhalation anaesthetics to the operating room air would be limited by more frequent use of total intravenous anaesthesia. The questionnaire results show that the predominating method of anaesthesia applied in our country uses inhalation anaesthetics. According to respondents from teaching hospitals, the major impediment of wider use of TIVA is the force of habit; respondents from lower referral level hospitals considered financial and equipment limitations the main reason of such a situation.

The place of N2O in modern anaesthesiology has been widely discussed [13, 14]. In our survey, the vast majority of respondents admit discontinuation of its use by 2010; 1-7% of respondents state that N2O has not been used any more. The commonest prerequisite of its cessation was related to better technical equipment of operating rooms and no financial limitations; however, some respondents think that elimination of this agent should be dependent on the introduction of suitable standards and legal regulations. The majority of opponents of N2O cessation believe that this anaesthetic is cheap, well known and its emission from medical sources is very low [14].

According to 90% of respondents, operating room contamination with inhalation anaesthetics should be measured, irrespective of the hospital referral level. This seems to be an encouraging opinion as for the perception of environmental pollution by the Polish anaesthesiologists. 

Furthermore, to get more information, possible differences between three regions of our survey were analysed. The differences, however, do not allow concluding that in any of those regions the risk of operating room pollution is higher.

The exposure to inhalation anaesthetics is not the only harmful risk factor amongst many thousands of operating room workers. Ionizing, electromagnetic radiation or effects of disinfectants are equally or more hazardous; nevertheless, the reduction in inhalation anaesthetic pollution should be considered essential. Additionally to suitable technical equipment of operating rooms and regular testing of air cleanliness, awareness of potential risks and education regarding the methods reducing pollution risks are necessary.

The data presented in our study show the ecological conditions of operating rooms in all provinces at the end of the first quarter of 2007. The successive introduction of new anaesthetic devices and continuous further professional education of anaesthesiologists were likely causes of more common use of ecologically safer methods of anaesthesia. It should be hoped that since the time the completed questionnaires were returned or in the nearest future the modernization of Polish operating rooms should improve their conditions. The initiation or near plans of renovations of operating rooms were signalled by some respondents of our questionnaire. To provide ecologically safe work places, which are our common interest, the standards of operating room equipment ought to be followed by the hospital staff and authorities.

CONCLUSIONS

1. The risk of operating room air contamination with inhalation anaesthetics in Polish hospitals is still high, which is related to poor technical infrastructure of those rooms. 

2. The incidence of risk factors is related to the referral levels of hospitals yet not to their geographic location.

3. The ecological safety of Polish operating rooms is also affected by the human factor, which is associated with routine, but not always suitable measures of anaesthetic management.

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REFERENCES

1.    Szulc R, Taeger K, Jurczyk W, Harth M, Sobczyński P, Sobieszczyk S, Paradowski S: Skażenie środowiska sal operacyjnych wziewnymi środkami znieczulenia. Ocena stanu w Akademii Medycznej w Poznaniu. Nowiny Lekarskie 1998; 67: 671-690.

2.    Krajewski W, Kucharska M, Wesołowski W, Stetkiewicz J, Wrońska-Nofer T: Occupational exposure to nitrous oxide – the role of scavenging and ventilation systems in reducing the exposure level in operating rooms. Int J Hyg Environ Health 2007; 210: 133-138.

3.    Krajewski W, Kucharska M, Wesołowski W, Wrońska-Nofer T: Occupational exposure to anaesthetics: monitoring of airborne concentrations of nitrous oxide and halogenated anaesthetics in operating rooms. Pol J Environ Studies 2003; 12 (Suppl. I): 115-119.

4.    Łukaszewski M, Kübler A, Durek G: Spektrofotometryczna ocena poziomu zanieczyszczenia podtlenkiem azotu miejsca pracy personelu anestezjologicznego na blokach operacyjnych. Pol Merk Lek 2004; 101: 438-442.

5.    Szulc R, Nestorowicz A, Sobczyński P, Fijałkowska A, Stachecki I: Anestetyki wziewne w atmosferze sal operacyjnych. Badanie w dwóch makroregionach Polski. Anest Inten Terap 2004; 36: 113-118.

6.    Byhahn C, Wilke HJ, Westphal K: Occupational exposure to volatile anaesthetics: epidemiology and approaches to reducing the problem. CNS Drugs 2001; 15: 197-215.

7.    Marx T: Belastung des Arbeitsplatzes mit volatilen Anaesthetika und Lachgas. Anaesthesiol Intensivmed Notfallmed Schmerzther 1997; 32: 532-540.

8.    Pothmann W, Shimada K, Goerig M, Fuhlrott M, Schulte am Esch J: Belastungen des Arbeitsplatzes durch Narkosegase. Ursachen und Praevention. Anaesthesist 1991; 40: 339-346.

9.    Byhahn C, Westphal K: Causes of nitrous oxide contamination in operating rooms. Anesthesiology 1999; 91: 1960-1961.

10.    Meier A, Jost M, Ruegger M, Knutti R, Schlatter C: Narkosegasbelastung des Personals in der Kinderanaesthesie. Anaesthesist 1995; 44: 154-162.

11.    Kübler A: Standardy i wytyczne bezpiecznego znieczulenia w Polsce. Anest Inten Terap 1994; 26: 63-67.

12.    Imberti R, Preseglio I, Imbriani M, Ghittori S, Cimino F, Mapelli A: Low flow anaesthesia reduced occupational exposure to inhalation anaesthetics. Environmental and biological measurements in operating room personnel. Acta Anaesthesiol Scand 1995; 39: 586-591.

13.    Schoenherr ME, Hollmann MW, Graf B: Lachgas. Sinn oder Unsinn für die heutige Narkoseführung? Anaesthesist 2004; 53: 796-812.

14.    Stenqvist O, Husum B, Dale O: Nitrous oxide: an ageing gentleman. Acta Anaesthesiol Scand 2001; 45: 135-137.

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*Piotr Pałaszkiewicz

Landkreis Mittweida Krankenhaus gGmbH
Anaesthesie und Intensivtherapie
Gaertnerstrasse 2
09306 Rochlitz (Niemcy)
tel.: 0049/37377875334
fax: 0049/37377875110
e-mail: p.palas@t-online.de

received: 12.02.2010
accepted: 27.05.2010