Occupational exposure to volatile anaesthetics: epidemiology and approaches to reducing the problem

A study of worker isoflurane exposure levels in Australian veterinary workplaces

Isoflurane is commonly used in veterinary clinics to anesthetize patients and has known acute and chronic health effects. Exposure to isoflurane should be kept as low as reasonably achievable, to minimize the risk of potential health impacts on workers. This study aimed to evaluate the effectiveness of recommended hazard controls for the management of isoflurane exposure to veterinary staff performing regular anesthesia procedures in equine and small animal settings. Isoflurane exposures were assessed via personal passive sampling using a gas and vapor monitor. It was found that when commonly recommended controls are utilized, including active scavenging systems, leak testing circuitry before use, using a cuffed endotracheal tube, avoiding chamber or mask inductions, and recovering the patient on pure oxygen before disconnection from anesthetic circuitry, worker exposures were below the lowest international Occupational Exposure Standard (OEL) of 2 ppm, in both an equine and small animal setting, with exposures in the equine clinic results having an estimated arithmetic mean of 0.52 ppm (GSD = 1.52) and exposures in the small animal clinics results having an estimated arithmetic mean of 0.34 ppm (GSD = 2.06). Results indicate that additional hazard controls could reduce exposures further and include limiting the total minutes of exposure to isoflurane, delivering the lowest effective isoflurane % to the patient, minimizing the number of times vaporizers are refilled during a work shift, and ensuring that surgery room ventilation is maximized.

The occupational hazards of anesthesiologists: A literature review and evidence-based approach to prevention

BACKGROUND

An occupational hazard is any workplace condition that poses a risk to an employee's health. Occupational hazards are ubiquitous in the field of anesthesiology and often go underappreciated. These hazards warrant careful assessment and strategic preventative planning.

OBJECTIVE

This narrative literature review examines the occupational hazards encountered by anesthesiologists and discusses evidence-based techniques to mitigate these risks. Facilitating the health and safety of anesthesia professionals protects not only the providers themselves but also enhances patient care by reducing the possibility of medical errors due to occupational fatigue, stress, and injuries.

METHODS

A targeted search of PubMed and other databases (SCOPUS, Web of Science) was used to review the literature. Safety standard handbooks by the International Atomic Energy Agency, The Pan American Health Organization, The World Health Organization, and Food and Agriculture of the United Nations, were also consulted to provide the current guidelines for hazards discussed. Articles and information were included if they provided information about the occupational hazards of anesthesiologists or evidence-based prevention techniques for mitigating the hazards.

RESULTS

The occupational hazards are classified into physical, chemical, and biological categories. Evidence-based preventive measures are proposed and examined for each category.

CONCLUSION

This paper examines the challenges faced by anesthesiologists by categorizing the physical, chemical, and biological occupational hazards. Each identified hazard is accompanied by evidence-based strategies to mitigate its impact. By illuminating these issues, increased awareness among healthcare professionals, policymakers, and the public can foster a collective effort to improve the safety of the work of anesthesia providers.

Reduction of greenhouse gases emission through the use of tiletamine and zolazepam

Isoflurane is an anaesthetic gas widely used in both human and veterinary medicine. All currently used volatile anaesthetics are ozone-depleting halogenated compounds. The use of total intravenous anaesthesia (TIVA) allows to induce the effect of general anaesthesia by administering drugs only intravenously without the use of anaesthetic gases. This allows you to create a protocol that is safe not only for the patient, but also for doctors and the environment. However, so far, no anaesthetic protocol based on induction of anaesthesia with tiletamine-zolazepam without the need to maintain anaesthesia with anaesthetic gas has been developed. Our study showed that the use of this combination of drugs for induction does not require the use of additional isoflurane to maintain anaesthesia. Thanks to Dixon's up-and-down method we proved that with the induction of anaesthesia with tiletamine-zolazepam at a dose of 5 mg/kg the use of isoflurane is not needed to maintain anaesthesia in minimally invasive surgical procedures. Until now, this dose has been recommended by the producer for more diagnostic than surgical procedures or for induction of general anaesthesia. The maintenance was required with anaesthetic gas or administration of another dose of the tiletamine-zolazepam. The results obtained in this study will allow for a significant reduction in the consumption of isoflurane, a gas co-responsible for the deepening of the greenhouse effect, having a negative impact on patients and surgeons. These results are certainly the first step to achieving a well-balanced and safe TIVA-based anaesthetic protocol using tiletamine-zolazepam, the obvious goal of which will be to maximize both the safety of the patient, people involved in surgical procedures, and the environment itself. Being aware of the problem of the greenhouse effect, we are committed to reducing the consumption of anaesthetic gases by replacing them with infusion agents.

Environmental and Occupational Considerations of Anesthesia: A Narrative Review and Update

With an estimated worldwide volume of 266 million surgeries in 2015, the call for general inhalation anesthesia is considerable. However, widely used volatile anesthetics such as N2O and the highly fluorinated gases sevoflurane, desflurane, and isoflurane are greenhouse gases, ozone-depleting agents, or both. Because these agents undergo minimal metabolism in the body during clinical use and are primarily (≥95%) eliminated unchanged via exhalation, waste anesthetic gases (WAGs) in operating rooms and postanesthesia care units can pose a challenge for overall elimination and occupational exposure. The chemical properties and global warming impacts of these gases vary, with atmospheric lifetimes of 1-5 years for sevoflurane, 3-6 years for isoflurane, 9-21 years for desflurane, and 114 years for N2O. Additionally, the use of N2O as a carrier gas for the inhalation anesthetics and as a supplement to intravenous (IV) anesthetics further contributes to these impacts. At the same time, unscavenged WAGs can result in chronic occupational exposure of health care workers to potential associated adverse health effects. Few adverse effects associated with WAGs have been documented, however, when workplace exposure limits are implemented. Specific measures that can help reduce occupational exposure and the environmental impact of inhaled anesthetics include efficient ventilation and scavenging systems, regular monitoring of airborne concentrations of waste gases to remain below recommended limits, ensuring that anesthesia equipment is well maintained, avoiding desflurane and N2O if possible, and minimizing fresh gas flow rates (eg, use of low-flow anesthesia). One alternative to volatile anesthetics may be total intravenous anesthesia (TIVA). While TIVA is not associated with the risks of occupational exposure or atmospheric pollution that are inherent to volatile anesthetic gases, clinical considerations should be weighed in the choice of agent. Appropriate procedures for the disposal of IV anesthetics must be followed to minimize any potential for negative environmental effects. Overall, although their contributions are relatively low compared with those of other human-produced substances, inhaled anesthetics are intrinsically potent greenhouse gases and pose a risk to operating-room personnel if not properly managed and scavenged. Factors to reduce waste and minimize the future impact of these substances should be considered.

Chemical risk in hospital settings: Overview on monitoring strategies and international regulatory aspects

Chemical risk in hospital settings is a growing concern that health professionals and supervisory authorities must deal with daily. Exposure to chemical risk is quite different depending on the hospital department involved and might origin from multiple sources, such as the use of sterilizing agents, disinfectants, detergents, solvents, heavy metals, dangerous drugs, and anesthetic gases. Improving prevention procedures and constantly monitoring the presence and level of potentially toxic substances, both in workers (biological monitoring) and in working environments (environmental monitoring), might significantly reduce the risk of exposure and contaminations. The purpose of this article is to present an overview on this subject, which includes the current international regulations, the chemical pollutants to which medical and paramedical personnel are mainly exposed, and the strategies developed to improve safety conditions for all healthcare workers.

A 3D-printed Apparatus for Imaging Multiple Rats Simultaneously

CT (computerized tomography) is a necessary imaging modality for cancer staging and disease monitoring. Rodent models of cancer are commonly studied prior to human clinical trials, but CT in rodents can be difficult due to their small size and constant movement, which necessitates general anesthesia. Because microCT equipment is not always available, clinical CT may be a viable alternative. Limitations of microCT and clinical CT include biosecurity, anesthesia to limit image distortion due to motion, and cost. To address several of these constraints, we created a 3D-printed apparatus that accommodated simultaneous imaging of as many as 9 rats under gas anesthesia. Rats were anesthetized in series and placed in a 3 × 3 arrangement. To assess differences in attenuation between individual chambers and rows or columns in the device, we first imaged a standardized phantom plug as a control. We hypothesized that attenuation of specific rat organs would not be affected regardless of the location or position in the 3D-printed device. Four organs-liver, kidney, femur, and brain-were evaluated in 9 rats. For both the phantom and kidneys, statistically significant, but clinically negligible, effects on attenuation were noted between rows but not between columns. We attribute this finding to the absence of a top layer of the apparatus, which thus created asymmetric attenuation and beam hardening through the device. This apparatus allowed us to successfully image 9 rats simultaneously in a clinical CT machine, with negligible effects on attenuation. Planned improvements in this apparatus include completely enclosed versions for biosecure imaging.

Influence of Isoflurane Exposure for 15 Consecutive Days on Ovarian Function in Adult Female Mice

Female infertility after occupational exposure to inhaled anesthetic agents has attracted critical attention, but systematic studies focusing on the impact of inhaled anesthetics on the female reproductive system have not been well-established. We used a murine model to study the effect of isoflurane exposure on infertility in female adult mice and investigated the potential underlying mechanism. One hundred adult female C57 mice were randomly allocated into 5 groups exposed in air containing 0, 2500, 5000, 10 000 or 20 000 ppm isoflurane for 15 consecutive days. Estrous cycle length was measured based on vaginal smear examination, ovarian histopathologic enumeration of follicles, and serum estradiol (E₂), anti-Mullerian hormone (AMH), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) levels to assess the effect of isoflurane on ovarian reserve. Compared to the control group, significant prolongation of the estrous cycle of the adult female mice was observed in the 20 000 ppm isoflurane exposure group. Serum AMH was significantly decreased, and FSH and LH levels profoundly increased in the 5000, 10 000, and 20 000 ppm isoflurane exposure groups compared to the control group. The histopathologic examination revealed a reduced number of developing follicles and an increased number of atretic follicles after isoflurane exposure, but the difference was not statistically significant. Thus, exposure to a higher concentration of isoflurane might have an adverse effect on ovarian reserve in sexually-mature female mice.

Probabilistic health risk assessment of occupational exposure to isoflurane and sevoflurane in the operating room

Risk assessment is an important tool in predicting the possible risk to health. It heightens awareness by estimating the probability of adverse health effects in humans who are exposed to chemicals in the course of their work. Therefore, the present work aims to determine the occupational exposure of operating room staff to the volatile anesthetic gases, isoflurane and sevoflurane, and estimates non-cancer risk using the United States Environmental Protection Agency method. Air samples from the breathing zone of staff members were collected using the Occupational Safety and Health Administration Method 103 and analyzed using gas chromatography-mass spectroscopy. The results indicate that the measured concentrations of isoflurane and sevoflurane are below the National Institute of Occupational Safety and Health standard (2 ppm) for technicians and nurses, but not for anesthesiologists and surgeons. Moreover, the estimated non-cancer risk due to isoflurane is above the acceptable value for anesthesiologists (but acceptable for other occupational categories). A sensitivity analysis indicates that exposure time has the most effect on calculated risk (53.4%). Occupational exposure to anesthetic gases may endanger the health of operating room personnel. Therefore, control measures, such as daily testing of anesthetic devices, ensuring the effectiveness of ventilation systems, advanced scavenging methods, and regular training of staff are highly recommended.

Occupational exposures to hazardous chemicals and agents among healthcare workers in Bhutan

BACKGROUND

Occupational exposures to hazardous chemicals among healthcare workers can result in long-term adverse health outcomes. Research on such exposures from low- and middle-income countries is limited. The aim of this study was to estimate the prevalence of exposures to a range of chemicals used in healthcare settings among Bhutanese healthcare workers.

METHODS

A cross-sectional study was conducted among healthcare workers (n = 370) working in three hospitals in the western region of Bhutan. Demographic and occupational information was collected, and exposures to asthmagens, carcinogens, ototoxic and other agents were assessed using a web-based tool. The prevalence of exposure to these chemicals was calculated and the circumstances resulting in such exposures were examined.

RESULTS

The prevalence of exposure to one or more asthmagen, carcinogen, and ototoxic agent was 98.7%, 28.1%, and 7.6%, respectively; and was 6.2% for anesthetic gases and 2.2% for antineoplastic drugs. The most common exposures were to latex, and cleaning and disinfecting agents in the asthmagens group; formaldehyde in the carcinogens group; and p-xylene among ototoxic agents. The circumstances resulting in exposures were using latex gloves, using bleach and chlorhexidine for cleaning, using formaldehyde as a disinfectant and in the laboratory, and using p-xylene in the laboratory.

CONCLUSIONS

The results indicate that a large proportion of Bhutanese healthcare workers are occupationally exposed to chemicals linked to chronic diseases, with exposure prevalence higher than in high-income countries. The study provides information that can be used to formulate policies and to implement control measures to protect healthcare workers.

Selective bond breaking of halothane induced by electron transfer in potassium collisions

We present novel experimental results of negative ion formation of halothane (C₂HBrClF₃) upon electron transfer from hyperthermal neutral potassium atoms (K°) in the collision energy range of 8-1000 eV. The experiments were performed in a crossed molecular beam setup allowing a comprehensive analysis of the time-of-flight (TOF) mass negative ions fragmentation pattern and a detailed knowledge of the collision dynamics in the energy range investigated. Such TOF mass spectra data show that the only negative ions formed are Br^-, Cl^- and F^-, with a strong energy dependence in the low-energy collision region, with the bromine anion being the most abundant and sole fragment at the lowest collision energy probed. In addition, potassium cation (K⁺) energy loss spectra in the forward scattering direction were obtained in a hemispherical energy analyser at different K° impact energies. In order to support our experimental findings, ab initio quantum chemical calculations have been performed to help interpret the role of the electronic structure of halothane. Potential energy curves were obtained along the C-X (X = Br, Cl) coordinate to lend support to the dissociation processes yielding anion formation.

Polymorphism in GSTM1 and GSTT1 genes influence DNA damage in personnel occupationally exposed to volatile anaesthetics (VA), from Peshawar, Pakistan

Objectives

The objective of this study was to assess the influence of antioxidant gene GSTM1 and GSTT1 on DNA damage in personnel occupationally exposed to volatile anaesthetics (VA).

Methods

The study groups were composed of 50 exposed subjects (anaesthesia workers) and 49 controls. Blood samples were collected from both subjects. DNA damage was analysed through the comet assay technique. Biomarker genes GSTM1 and GSTT1 were inspected through PCR technique for polymorphism.

Results

The comet assay technique showed that the Total Comet Score (TCS) in exposed subjects was significantly higher (p=0.0001) than the control. Age and smoking had significant effects on TCS in the study groups (p<0.05). Duration of occupational exposure had significant positive correlation (r=0.755, p<0.001) with DNA damage. The null polymorphism in GSTM1 and GSTT1 gene showed a significant effect (p<0.001 and p<0.000) on the DNA damage.

Conclusions

The polymorphism in GSTM1 and GSTT1 gene significantly damage DNA in personnel occupationally exposed to VA.

High concentrations of waste anesthetic gases induce genetic damage and inflammation in physicians exposed for three years: A cross-sectional study

This cross-sectional study analyzed the impact of occupational waste anesthetic gases on genetic material, oxidative stress, and inflammation status in young physicians exposed to inhalational anesthetics at the end of their medical residency. Concentrations of waste anesthetic gases were measured in the operating rooms to assess anesthetic pollution. The exposed group comprised individuals occupationally exposed to inhalational anesthetics, while the control group comprised individuals without anesthetic exposure. We quantified DNA damage; genetic instability (micronucleus-MN); protein, lipid, and DNA oxidation; antioxidant activities; and proinflammatory cytokine levels. Trace concentrations of anesthetics (isoflurane: 5.3 ± 2.5 ppm, sevoflurane: 9.7 ± 5.9 ppm, and nitrous oxide: 180 ± 150 ppm) were above international recommended thresholds. Basal DNA damage and IL-17A were significantly higher in the exposed group [27 ± 20 a.u. and 20.7(19.1;31.8) pg/mL, respectively] compared to the control group [17 ± 11 a.u. and 19.0(18.9;19.5) pg/mL, respectively], and MN frequency was slightly increased in the exposed physicians (2.3-fold). No significant difference was observed regarding oxidative stress biomarkers. The findings highlight the genetic and inflammatory risks in young physicians exposed to inhalational agents in operating rooms lacking adequate scavenging systems. This potential health hazard can accompany these subjects throughout their professional lives and reinforces the need to reduce ambient air pollution and consequently, occupational exposure.

Detrimental effects detected in exfoliated buccal cells from anesthesiology medical residents occupationally exposed to inhalation anesthetics: An observational study

Operating room professionals are scarcely aware of their individual occupational exposure to waste anesthetic gases (WAGs). Medical residents spend several hours per day in operating rooms and consequently experience occupational exposure to WAGs. Considering that no studies have yet evaluated the potential toxicity in medical residents exposed to WAGs using the buccal micronucleus cytome (BMCyt) assay, this pioneering study aimed to compare the BMCyt assay markers, including DNA damage, cell proliferation, and cell death in the exfoliated buccal cells of surgery and anesthesiology residents occupationally exposed to WAGs. The study enrolled a total of 60 physicians, including internal medicine residents (unexposed group), and residents from surgery and anesthesiology programs who were occupationally exposed to sevoflurane, isoflurane and nitrous oxide. WAGs were measured, and the mean values were higher than the international recommendation. The anesthesiology residents (high exposure) showed statistically significant lower frequencies of basal cells, and statistically significant higher frequencies of micronuclei, karyorrhexis, pyknosis, and differentiated cells than did the unexposed group; karyolysis frequencies were significantly higher in anesthesiology residents than were those in the unexposed group or in surgical residents (low exposure). The findings suggest a genetic risk for young professionals exposed to WAGs at the beginning of their careers. Thus, exposure to high WAGs concentrations leads to impairment of the buccal cell proliferative potential, genomic instability and cell death, especially in anesthesiology residents, demonstrating an early impact on their health.

Environmental and biological measurements of isoflurane and sevoflurane in operating room personnel

PURPOSE

The present study aimed to compare the concentration of isoflurane and sevoflurane in the individual's breathing zone and ambient air of operating rooms (ORs), to investigate the correlation between breathing zone levels and urinary concentrations, and to evaluate the ORs pollution in the different working hours and weeks.

METHODS

Environmental and biological concentrations of isoflurane and sevoflurane were evaluated at 9ORs. Air samples were collected by active sampling method and urine samples were collected from each subject at the end of the work shift. All samples were analyzed using gas chromatography.

RESULTS

The geometric mean ± GSD concentration of isoflurane and sevoflurane in breathing zone air were 1.41 ± 2.27 and 0.005 ± 1.74 ppm, respectively, while in post-shift urine were 2.42 ± 2.86 and 0.006 ± 3.83 µg/l_urine, respectively. A significant positive correlation was found between the urinary and environmental concentration of isoflurane (r ² = 0.724, P < 0.0001). The geometric mean ± GSD values of isoflurane and sevoflurane in ambient air were 2.30 ± 2.43 and 0.004 ± 1.56 ppm, respectively. The isoflurane concentration was different for three studied weeks and significantly increased over time in the ambient air of ORs.

CONCLUSIONS

The occupational exposure of OR personnel to isoflurane and sevoflurane was lower than national recommended exposure limits. The urinary isoflurane could be a good internal dose biomarker for monitoring of occupational isoflurane exposure. Considering the accumulation of anesthetic waste gases in the studied ORs, real-time air monitoring is better to be done at the end of the work shift.

Economic Evaluation of Pharmacologic Pre- and Postconditioning With Sevoflurane Compared With Total Intravenous Anesthesia in Liver Surgery: A Cost Analysis

BACKGROUND

Pharmacologic pre- and postconditioning with sevoflurane compared with total IV anesthesia in patients undergoing liver surgery reduced complication rates as shown in 2 recent randomized controlled trials. However, the potential health economic consequences of these different anesthesia regimens have not yet been assessed.

METHODS

An expostcost analysis of these 2 trials in 129 patients treated between 2006 and 2010 was performed. We analyzed direct medical costs for in-hospital stay and compared pharmacologic pre- and postconditioning with sevoflurane (intervention) with total IV anesthesia (control) from the perspective of a Swiss university hospital. Year 2015 costs, converted to US dollars, were derived from hospital cost accounting data and compared with a multivariable regression analysis adjusting for relevant covariables. Costs with negative prefix indicate savings and costs with positive prefix represent higher spending in our analysis.

RESULTS

Treatment-related costs per patient showed a nonsignificant change by -12,697 US dollars (95% confidence interval [CI], 10,956 to -36,352; P = .29) with preconditioning and by -6139 US dollars (95% CI, 6723 to -19,000; P = .35) with postconditioning compared with the control group. Results were robust in our sensitivity analysis. For both procedures (control and intervention) together, major complications led to a significant increase in costs by 86,018 US dollars (95% CI, 13,839-158,198; P = .02) per patient compared with patients with no major complications.

CONCLUSIONS

In this cost analysis, reduced in-hospital costs by pharmacologic conditioning with sevoflurane in patients undergoing liver surgery are suggested. This possible difference in costs compared with total IV anesthesia is the result of reduced complication rates with pharmacologic conditioning, because major complications have significant cost implications.

Exposure to volatile anaesthetics is not followed by a massive induction of single-strand DNA breaks in operation theatre personnel

Volatile anaesthetics such as halothane, isoflurane and others were expected to produce a health challenge for operation room personnel because of prolonged occupational exposure to anaesthetic gases. To estimate a molecular background of adverse health effects, a cohort of 100 exposed individuals was studied by the single-cell gene electrophoresis (comet assay) test. DNA lesions in lymphocytes of the exposed group did not differ significantly compared with non-exposed blood donors. Then, the exposed group was further divided according to job position. A highest level of DNA lesions was established in nurses but without significant difference compared with other groups. When a time period of exposure was taken into account, a tendency to cumulate DNA lesions was found only in the group of anaesthesiologists. A very weak genotoxic effect established in this study is discussed in relation to DNA repair, adaptative response and potential self-elimination of sensitive individuals.

Application of predictive models for estimation of health care workers exposure to sevoflurane

OBJECTIVES

The aim of this study was to assess the potential use of predictive models to estimate professional exposure to chemicals in the workplace, such as the operating room, by simultaneous determination of the levels of exposure using a model and measurements.

METHODS

Measurements included determinations of sevoflurane (SEV) in the workplace air of 117 operating rooms of 31 hospitals in one Polish region. Measurements were carried out at the time of various surgical procedures during administration of anaesthetics by endotracheal intubation. The measurement results were compared with the values estimated using two models: ECETOC TRA and Stoffenmanager.

RESULTS

In one case the ECETOC TRA estimated the exposure concentration almost equal to the measured concentration but, because of the need to maintain a margin of safety in case of modelling, it can be concluded that the model underestimated the concentration. The Stoffenmanager model provided accurate exposure estimates in the examined case, and it can be used as a screening tool for the assessment of occupational inhalation exposure of medical personnel to anaesthetics.

CONCLUSIONS

The results are of particular importance to the circumstances in Eastern Europe, where the levels of anaesthetics often exceed the relevant occupational exposure limits.

Breath gas concentrations mirror exposure to sevoflurane and isopropyl alcohol in hospital environments in non-occupational conditions

Anaesthetic gases and disinfectants are a primary source of air contamination in hospitals. A highly sensitive sorbent-trap methodology has been used to analyse exhaled breath samples with detection limits in the pptv range, which allows volatile organic compounds (VOCs) to be detected at significantly lower levels (5-6 orders of magnitude below) than the recommended exposure limits by different organizations. Two common VOCs used in hospital environments, isopropyl alcohol (IPA) and sevoflurane, have been evaluated. Forced-expiratory breath samples were obtained from 100 volunteers (24 hospital staff, 45 hospital visitors and 31 external controls). Significant differences for IPA were found between samples from volunteers who had not been in contact with hospital environments (mean value of 8.032 ppbv) and people staying (20.981 ppbv, p  =  0.0002) or working (19.457 ppbv, p  =  0.000 09) in such an environment. Sevoflurane, an anaesthetic gas routinely used as an inhaled anaesthetic, was detected in all samples from volunteers in the hospital environment but not in volunteers who had not been in recent contact with a hospital environment. The levels of sevoflurane were significantly higher (p  =  0.000 24) among staff members (0.522 ppbv) than among visitors to the hospital (0.196 ppbv). We conclude that highly sensitive methods are required to detect anaesthetic gas contamination in hospital environments.

Biomonitoring occupational sevoflurane exposure at low levels by urinary sevoflurane and hexafluoroisopropanol

This study aimed to correlate environmental sevoflurane levels with urinary concentrations of sevoflurane (Sev-U) or its metabolite hexafluoroisopropanol (HFIP) in order to assess and discuss the main issues relating to which biomarker of sevoflurane exposure is best, and possibly suggest the corresponding biological equivalent exposure limit values. Individual sevoflurane exposure was measured in 100 healthcare operators at five hospitals in north-east Italy using the passive air sampling device Radiello(®), and assaying Sev-U and HFIP concentrations in their urine collected at the end of the operating room session. All analyses were performed by gas chromatography-mass spectrometry. Environmental sevoflurane levels in the operating rooms were also monitored continuously using an infrared photoacoustic analyzer. Our results showed very low individual sevoflurane exposure levels, generally below 0.5 ppm (mean 0.116 ppm; range 0.007-0.940 ppm). Sev-U and HFIP concentrations were in the range of 0.1-17.28 μg/L and 5-550 μg/L, respectively. Both biomarkers showed a statistically significant correlation with the environmental exposure levels (Sev-U, r=0.49; HFIP, r=0.52), albeit showing fairly scattered values. Sev-U values seem to be influenced by peaks of exposure, especially at the end of the operating-room session, whereas HFIP levels by exposure on the previous day, the data being consistent with the biomarkers' very different half-lives (2.8 and 19 h, respectively). According to our results, both Sev-U and HFIP are appropriate biomarkers for assessing sevoflurane exposure at low levels, although with some differences in times/patterns of exposure. More work is needed to identify the best biomarker of sevoflurane exposure and the corresponding biological equivalent exposure limit values.

Long-term allergic dermatitis caused by sevoflurane: a clinical report

BACKGROUND

Allergy to volatile anaesthetics is extremely rare, but capable of damaging the professional career.

METHODS

This article presents the case of a 60-year-old surgeon who developed a skin rash on the reverse of hands, which progressively worsened and extended to distant fold areas. Blood tests were normal but for eosinophilia and risen total IgE, with normal specific globulins and skin prick tests for common allergens. After 8 years, a malfunction in the anaesthetic gas scavenging system was found, and symptoms remitted within a week following its replacement. Repeated open application test with sevoflurane led to the appearance of the same lesions in the tested areas and in distant body folds.

RESULTS

We hypothesize that the most probable mechanism for the reaction in our patient is systemic allergic contact dermatitis, which is caused by repeated systemic exposure to a hapten that reaches the skin through haematogenous transport in a sensitized patient.

CONCLUSIONS

The report aims to warn about the potential aetiological relationship between exposure to inhaled anaesthetics and allergic manifestations with cutaneous symptoms.

Quantitative chemical analysis of surgical smoke generated during laparoscopic surgery with a vessel-sealing device

BACKGROUND

Exposure to surgical smoke in the operation room has been a long-standing concern. Smoke generated by the interaction between lasers or electrocautery devices with biological tissue contains several toxic and carcinogenic substances, but only a few studies so far have provided quantitative data necessary for risk assessment.

METHODS

With laser and Fourier-transform infrared spectroscopy, we investigated the chemical composition of smoke produced with a vessel-sealing device in an anoxic environment during laparoscopic surgery.

RESULTS

Harmless concentrations of methane (<34 ppm), ethane (<2 ppm), and ethylene (<10 ppm) were detected. Traces of carbon monoxide (<3.2 ppm) and of the anesthetic sevoflurane (<450 ppm) were also found. CONCLUSIONS. Gas leaking or gas being released from the pneumoperitoneum could therefore increase pollution by waste anesthetic gas in the operating room. Most toxic compounds found in earlier studies remained undetected. Adverse health effects for operating room personnel due to some of those substances (e.g., toluene, styrene, xylene) can be excluded, assuming no significant losses or changes in the chemical composition of the samples occurred between our sampling and measurements.

Environmental implications of anesthetic gases

For several decades, anesthetic gases have greatly enhanced the comfort and outcome for patients during surgery. The benefits of these agents have heavily outweighed the risks. In recent years, the attention towards their overall contribution to global climate change and the environment has increased. Anesthesia providers have a responsibility to minimize unnecessary atmospheric pollution by utilizing techniques that can lessen any adverse effects of these gases on the environment. Moreover, health care facilities that use anesthetic gases are accountable for ensuring that all anesthesia equipment, including the scavenging system, is effective and routinely maintained. Implementing preventive practices and simple strategies can promote the safest and most healthy environment.

Evaluation of tetrahydrobiopterin pathway in operating room workers: changes in biopterin status and tryptophan metabolism

The aim of the study was to evaluate the effect of anesthetics as operating room contaminants on tetrahydrobiopterin pathway in 40 operating room personnel and 30 healthy controls by measuring biopterin, dihydrobiopterin reductase, tryptophan, kynurenine and serotonin. Biopterin concentrations were 124 ± 12.3 µmol/mol creatinine in workers and 88 ± 5.7 µmol/mol creatinine in controls whereas kynurenine concentrations were 1.75 ± 0.09 µM and 1.95 ± 0.06 µM, respectively (both, p < 0.05). It can be claimed that enhanced biopterin and diminished kynurenine levels may play a triggering role in disruption of metabolic events in operating room personnel.

Effects of isoflurane inhalation on the male reproductive system in rats

The 15-day intact adult male assay was used to evaluate effects of isoflurane on the testes and sexual hormones. Forty adult male Sprague-Dawley rats were divided into five groups exposed to air containing 0, 50, 300, 1800 or 10,800 ppm isoflurane. After the treatments, serum was collected for the hormones assay. The right testis was to be used for daily sperm production. The left testis was processed for histopathology and electron microscopy observation. Daily sperm productions were significantly decreased at doses of 300, 1800 and 10,800 ppm. Impaired seminiferous tubules were noted at doses of 300, 1800 and 10,800 ppm. Ultrastructural changes included nucleus agglutination of spermatocytes, big lipid drops and autophagosome in cytoplasm. The serum follicle-stimulating hormone and testosterone concentrations reduced significantly at doses of 1800 and 10,800 ppm. Isoflurane induced impairments of seminiferous tubules and spermatogenesis. The testicular damages caused by isoflurane can be related to the imbalances in the sexual hormones.

Occupational exposure to isoflurane during anaesthesia induction with standard and scavenging double masks in dogs, pigs and ponies

Induction of anaesthesia using a face mask may cause workplace pollution with anaesthetics. The aim of this study was to compare the effect of the use of a standard versus a scavenging double face mask on isoflurane pollution during induction of anaesthesia in experimental animals: six dogs, 12 pigs and five ponies. Pigs were anaesthetized only once using either mask type randomly ( n = 6). Dogs and ponies were anaesthetized twice, using different mask types for each occasion in a random order with at least 14 days between experiments. The masks were attached to a Bain breathing system (dogs and pigs) or to a circle system (ponies) using a fresh gas flow of 300 or 50 mL/kg/min, respectively, with 5% vaporizer dial setting. Isoflurane concentrations were measured in the anaesthetist's breathing zone using an infrared photoacoustic spectrometer. The peak isoflurane concentrations (pollution) during baseline and induction periods were compared with Wilcoxon test in all species, and values between the mask types were compared with either Wilcoxon (ponies and dogs) or Mann–Whitney tests (pigs) ( P < 0.05). Pollution was higher during induction when compared with baseline regardless of the mask type used but it was only statistically significant in dogs and pigs. Pollution was lower during induction with double versus single masks but it was only significant in pigs. Despite the lack of statistical significance, large and consistent differences were noted in all species, hence using scavenging masks is recommended to reduce isoflurane workplace pollution.

Setting standards for simulation in anesthesia: the role of safety criteria in accreditation standards

PURPOSE

In this article, we describe a critical event which occurred in a simulation centre, and we also review possible safety issues for participants and staff involved in medical simulation training.

PRINCIPAL FINDINGS

The authors report an incident with the potential of harming trainees and staff which occurred during a full-scale simulation. The episode raised the question of training safety in simulation centres. In this instance, the computer program controlling the mannequin enabled a continuous and non-regulated outflow of carbon dioxide which led to an intense reaction in the soda lime canister. The absorbent canister became too hot to be touched (a temperature probe, later placed in the centre of the front canister, measured 53°C). All activities involving the mannequin and anesthesia machine were stopped immediately.

CONCLUSIONS

Simulation in healthcare is a valuable educational tool to train for a variety of clinical encounters in a safe environment without harming a patient. Due to technological progress and the use of authentic equipment recreating near real environments, simulation training has become exceedingly realistic. The Society for Simulation in Healthcare (SSH) has published revised accreditation standards for simulation centres which incorporate training safety sub-criteria to address and manage. By highlighting recommendations of other high-risk industries on this issue, SSH proposes a possible approach to enhance safety in medical simulation.

Intravenous thiamylal and local anesthetic infiltration for pediatric facial repair procedures performed in emergency departments

Thiamylal is widely used for procedural sedation in emergency departments (ED); however, there are limited safety data for doses of thiamylal > 5 mg/kg in children. We investigated whether intravenous thiamylal in combination with local anesthetics is safe and effective for pediatric procedural sedation in the ED and to identify the association between increasing doses thiamylal and adverse events. Between July 2004 and June 2008, 227 children who underwent procedural sedation met the inclusion criteria, including 105 males (46.3%) and 122 females (53.7%). Facial laceration was the most common indication for procedural sedation. All children received an intravenous injection of thiamylal, with a loading dose of 5 mg/kg. Eighty-one children (35.7%) received a supplemental dose of 2.5 mg/kg thiamylal because of inadequate sedation. Of these, 27 (11.9%) received a second supplemental dose of 2.5 mg/kg because of inadequate sedation. Sixty-six patients (29.1%) experienced 75 mild and self-resolving adverse events, and most of which (15/75; 20%) were drowsiness. Four (1.8%) patients experienced oxygen saturation below 96%, which was related to the supplemental dose of thiamylal (p = 0.002). No children suffered from any lasting or potentially serious complications. Our results indicate that intravenous thiamylal in combination with local anesthetic infiltration is a well tolerated for therapeutic procedures in the ED. Thiamylal offers rapid onset of sedation without compromising the patient's cardiorespiratory function during pediatric procedural sedation.

Sedation management in Australian and New Zealand intensive care units: doctors' and nurses' practices and opinions

OBJECTIVE

To explore the use of sedatives and analgesics, tools for scoring level of sedation, sedation and pain protocols, and daily interruptions in sedation in Australian and New Zealand intensive care units and to examine doctors' and nurses' opinions about the sedation management of critically ill patients.

METHODS

A cross-sectional Internet-based survey design was used. In total, 2146 members of professional critical care organizations in Australia and New Zealand were e-mailed the survey during a 4-month period in 2006 through 2007.

RESULTS

Of 348 members (16% response rate) who accessed the survey, 246 (71%) completed all sections. Morphine, fentanyl, midazolam, and propofol were the most commonly used medicines. Newer medicines, such as dexmedetomidine and remifentanil, and inhalant medications, such as nitrous oxide and isoflurane, were rarely used by most respondents. Respondents used protocols to manage sedatives (54%) and analgesics (51%), and sedation assessment tools were regularly used by 72%. A total of 62% reported daily interruption of sedation; 23% used daily interruption for more than 75% of patients. A disparity was evident between respondents' opinions on how deeply patients were usually sedated in practice and how deeply patients should ideally be sedated.

CONCLUSIONS

Newer medications are used much less than are traditional sedatives and analgesics. Sedation protocols are increasingly used in Australasia, despite equivocal evidence supporting their use. Similarly, daily interruption of sedation is common in management of patients receiving mechanical ventilation. Research is needed to explore contextual and personal factors that may affect sedation management.

Do we need inhaled anaesthetics to blunt arousal, haemodynamic responses to intubation after i.v. induction with propofol, remifentanil, rocuronium?

BACKGROUND

The aim of this study was to determine whether, after propofol, rocuronium and remifentanil rapid sequence induction, inhaled anaesthetic agents should be started before intubation to minimize autonomic and arousal response during intubation.

METHODS

One hundred ASA I and II patients were randomized to receive 1 MAC of desflurane or sevoflurane during manual ventilation or not. Anaesthesia was induced with an effect-site-controlled infusion of remifentanil at 2 ng ml(-1) for 3 min. Patients then received propofol to induce loss of consciousness (LOC). Rocuronium (0.6 mg kg(-1)) was given at LOC and the trachea was intubated after 90 s of manual breathing support (=baseline) with or without inhaled anaesthetics. Vital signs and bispectral index (BIS) were recorded until 10 min post-intubation to detect autonomic and arousal response.

RESULTS

A significant increase in BIS value after intubation was seen in all groups. The increases were mild, even in those not receiving pre-intubation inhaled anaesthetics. However, in contrast to sevoflurane, desflurane appeared to partially blunt the arousal response. Heart rate, systolic and diastolic pressure increase similarly in all groups.

CONCLUSIONS

Desflurane and sevoflurane were unable to blunt the arousal reflex completely, as measured by BIS, although the reflex was significantly less when desflurane was used. Rapid sequence induction with remifentanil, propofol and rocuronium and without inhaled anaesthetics before intubation can be done without dangerous haemodynamic and arousal responses at intubation after 90 s.

Oxidative stress in operating room personnel: occupational exposure to anesthetic gases

Health professionals exposed to anesthetic gases are at higher risk of reproductive, neurological, hematological, immunological, hepatic and renal system diseases. We investigated if oxidative stress induced by chronic exposure to anesthetic gases has any association with this matter. Plasma lipid peroxidation, total antioxidant capacity and total thiol molecule levels were measured in 66 operating room staff in comparison with 66 controls. The exposed group had a significantly higher level of lipid peroxidation with decreased thiol groups compared to control subjects. Total antioxidant capacity of the body was no different among exposed and not exposed subjects. Increased lipid peroxidation in the blood of exposed subjects warns that oxygen free radicals have increased in the body and thus might attack cells, which, in the long-term, results in multi-organ damage. The remaining blood total antioxidant capacity at normal values is promising and means that other non-thiol antioxidants, such as uric acid, transferrin, ceruloplasmin, albumin, and vitamin antioxidants, such as alpha-tocopherol and ascorbic acid, have been stimulated to maintain the total anti-oxidant power of the body at normal state.

Halothane, an effective infrequently used drug, in the treatment of pediatric status asthmaticus: a case report

Asthma is the most common chronic disease of childhood. Despite a better understanding of the disease process and its management, status asthmaticus continues to be a life-threatening event. The use of volatile inhaled anesthetics is infrequently reported as adjunctive therapy to conventional treatment of this condition. We report the use of halothane in a mechanically ventilated pediatric patient with life-threatening status asthmaticus who was admitted to the pediatric intensive care unit (PICU) after failing to respond to standard medical therapy and noninvasive positive pressure ventilation. A 12-year-old African American male was seen in the emergency department and treated with intravenous corticosteroids, beta-agonist therapy. He deteriorated rapidly and required endotracheal intubation and mechanical ventilation. Two hours later, the patient developed an acute, severe respiratory acidosis (pH=6.97, PaCO2=171, PaO2=162, BE=1.7). Halothane was started at 2% by using the Siemens Servo 900C anesthesia ventilator. Improvement in both arterial blood gases and exhaled tidal volume were noted 30 minutes after initiation of the anesthetic gas. The patient remained on halothane for a total of 36 hours. No adverse effects associated with the use of halothane were noted. The patient was extubated to BiPAP 16/6, FiO2=0.30 at 68 hours and was discharged home 5 days later.

Effect of volatile anesthetics on oxidative stress due to occupational exposure

Possible health hazards from long-term exposure to inhalation anesthetics cannot yet be definitively excluded. One of the adverse effects of general anesthetics is the exogen sources of reactive oxygen radicals that are responsible for several diseases. We designed the present study to determine the effect of volatile anesthetics on oxidative stress due to occupational exposure. We enrolled 30 anesthesia and surgery personnel who had been exposed to inhalation anesthetics for 3 years and 30 healthy volunteer personnel who had not been exposed to inhalation anesthetics at any period of their life as the control group. Blood samples were taken from both groups for determination of superoxide dismutase, glutathione peroxidase, and their cofactors, which are selenium, copper, and zinc levels. Our results revealed that plasma and erythrocyte antioxidant activity and trace element levels were significantly lower in operating room personnel compared to that in the control groups. We concluded that the antioxidant defense system was affected by free radical injury in anesthesia and surgery personnel who had been exposed to inhalation anesthetics chronically. Therefore, minimizing occupational exposure to volatile anesthetics is important for protecting operation room personnel from hazards. Operating room personnel should also take antioxidant supplements.

Urinary sevoflurane and hexafluoro-isopropanol as biomarkers of low-level occupational exposure to sevoflurane

OBJECTIVES

Sevoflurane is an inhalation halogenated anaesthetic widely used in day and paediatric surgery. We were interested in evaluating biological markers of exposure to sevoflurane, which should improve the health surveillance of occupationally exposed personnel.

METHODS

A group of 36 subjects (13 male, 23 female) occupationally exposed to volatile anaesthetics in paediatric operating rooms was studied in a 2-week survey. Post-shift urine samples and specimens from passive samplers (for personal monitoring) were collected after 1.75-6 h morning exposure and analysed by headspace gas chromatography-mass spectrometry (GC-MS). Multiple determinations were assumed as independent values (in total, n = 78: 24 from men, 54 from women; 25 from smokers, 53 from non-smokers).

RESULTS

Median sevoflurane external values were 0.13 parts per million (ppm) (range 0.03-18.82) (n = 78), urinary sevoflurane 0.6 microg/l urine (ND-18.5)(n = 76) and total urinary hexafluoro-isopropanol (HFIP) 0.49 mg/l urine (ND-6833.4) (n = 75). A lower limit of detection (LOD) was achieved for urinary sevoflurane (0.03 microg/l urine), allowing quantitation of all but one of the samples; >25% of urine samples were unquantifiable by HFIP and were assigned a value equal to half the LOD of 0.10 mg/l(urine). Urinary sevoflurane correlated well with breathing-zone data (r2 = 0.697 at log-log linear regression), whereas total urinary HFIP (r2 = 0.562 at log-log linear regression) seemed to be better described by a three-parameter logistic function and appeared to be influenced by smoking habits. Biological indices corresponding to National Institute for Occupational Safety and Health (NIOSH) exposure limits, calculated as means of linear regression slope and y intercept, were 3.9 mug/l(urine) and 1.4 microg/l urine for sevoflurane (corresponding to 2 ppm and 0.5 ppm, respectively), and 2.66 mg/l urine and 0.82 mg/l urine for HFIP.

CONCLUSIONS

On the basis of our data, urinary unmodified, sevoflurane seems to be a more sensitive and reliable biomarker of short-term exposure to sevoflurane with respect to total urinary metabolite HFIP, which appears to be influenced by physiological and/or genetic individual traits, and seems to provide an estimate of integrated exposure.

Assessing the health implications for healthcare workers of regulatory changes eliminating locally developed occupational exposure limits in favor of TLVs: an evidence-based bipartite approach

In response to the intention of the Workers' Compensation Board of British Columbia (WCB of BC) to eliminate made-in-BC occupational exposure limits (OELs) and adopt threshold limit values (TLVs), this study assessed the potential health impacts on healthcare workers (HCWs) of the proposed change, by (1) reviewing the processes used to establish the OELs and TLVs, (2) selecting of substances of health concern for HCWs, (3) identifying chemicals with discordances between existing OELs and the 2002 TLVs, and 4) reviewing the discordances and assessing the potential health implications. Differences in philosophies, policies and processes that influenced the setting of OELs and TLVs were substantial. The TLV process involves U.S. and international priorities; in BC, a tripartite committee determined OELs taking into consideration how OELs should be interpreted in the local context. 47 chemicals of concern to BC HCWs were discordant, with significant discordances totalling 57; 15 compounds had BC 8-hour OELs lower than their respective TLVs and three TLVs were lower than the 8-hour BC OELs. Review of six chemicals with discordances suggested a potential for increased risks of adverse health effects. Eliminating the local capacity and authority to set OELs is unlikely to cause major health problems in the short run, but as chemicals in use locally may not have up-to-date TLVs, eliminating the capacity for local considerations should be undertaken with great caution. While the WCB of BC did implement the change, the present report resulted in procedural changes that will provide better protection for the workforce.

Veterinary pharmacovigilance. Part 4. Adverse reactions in humans to veterinary medicinal products

Although seemingly rare, adverse reactions to veterinary products do occur. These may arise from inadvertent exposure during use or as a result of occupational accidents. They are often mild in nature and include adverse effects such as minor skin reactions. However, more serious reactions may occur, and they are not restricted to the effects of the veterinary medicines themselves. For example, high-pressure injection injuries may occur as a result of accidents occurring during animal vaccination operations. This paper reviews some of these events, mentions where appropriate the regulatory actions taken, and describes some of the measures used to minimise such effects in the future, and serves to bring the issues discussed here to the attention of pharmacologists, pharmacoepidemiologists and others who train those who use veterinary medicinal products.