Anaesthesia practice and reproductive outcomes: Facts unveiled

Occupational Exposure to Inhalational Anesthetics and Teratogenic Effects: A Systematic Review

(1) Background: In the current healthcare environment, there is a large proportion of female staff of childbearing age, so, according to existing conflicting studies, the teratogenic effects that inhalational anesthetics may have on exposed pregnant workers should be assessed. This investigation aims to analyze the teratogenic effects of inhalational anesthetics in conditions of actual use, determining any association with spontaneous abortion or congenital malformations. (2) Methods: A systematic review was carried out according to the PRISMA statement based on PICO (problem of interest–intervention to be considered–intervention compared–outcome) (Do inhalational anesthetics have teratogenic effects in current clinical practice?). The level of evidence of the selected articles was evaluated using the SIGN scale. The databases used were PubMed, Embase, Scopus, Web of Science, Google academic and Opengrey. Primary studies conducted in professionals exposed to inhalational anesthetics that evaluate spontaneous abortions or congenital malformations, conducted in any country and language and published within the last ten years were selected. (3) Results: Of the 541 studies identified, 6 met all inclusion criteria in answering the research question. Since many methodological differences were found in estimating exposure to inhalational anesthetics, a qualitative systematic review was performed. The selected studies have a retrospective cohort design and mostly present a low level of evidence and a low grade of recommendation. Studies with the highest level of evidence do not find an association between the use of inhalational anesthetics and the occurrence of miscarriage or congenital malformations. (4) Conclusions: The administration of inhalational anesthetics, especially with gas extraction systems (scavenging systems) and the adequate ventilation of operating rooms, is not associated with the occurrence of spontaneous abortions or congenital malformations.

Effect of simultaneous exposure to inhalational anesthetics and radiation on the adaptive response in operating room personnel

Some operating room personnel, such as orthopedic surgeons, are exposed simultaneously to inhalational anesthetics (IAs) and radiation that both can cause DNA damage. Some studies have shown that low doses of radiation reduce DNA damage when the cells are followed by a higher dose of the same or related agent. This study, therefore, set out to compare DNA damage in the anesthesiologists, radiologists, orthopedic surgeons, and healthcare staff (non-exposed group). In this cross-sectional study, breathing zone concentrations of anesthetic gas nitrous oxide (N₂O) were measured in the studied groups using standard method. Additionally, DNA damage was measured by micronucleus (MN) assay. The mean concentrations of N₂O in the anesthesiologists and orthopedic surgeons were 450.27 ± 327.44 ppm and 313.64 ± 216.14 ppm, respectively. The mean annual exposure to X-rays radiation in radiologists and orthopedic surgeons was 15.65 ± 8.46 mSy/year and 3.56 ± 1.32 mSy/year, respectively. MN frequencies were significantly higher in anesthesiologists and radiologists exposed to IAs and X-rays radiation respectively than in the non-exposed healthcare staff. While, there were no statistically significant differences between MN frequencies of orthopedic surgeons exposed to both IAs and radiation and healthcare staff. These findings suggest that an earlier exposure of orthopedic surgeons to a small dose of ionizing radiation can increase their resistance to genotoxicity caused by high doses of N₂O, a phenomenon that is called adaptive response.

Spontaneous abortion in women occupationally exposed to inhalational anesthetics: a critical systematic review

Occupational exposure to inhalational anesthetics has been associated with health problems, including reproductive issues. Considering the scarcity and outdated nature of reviews concerning this relevant topic, which has implications for indoor pollution/environmental science/public health, this critical review aimed to systematically evaluate whether exposure to inhalational anesthetics is associated with abortion. Seven databases were searched with no language or year restrictions. Of the 3881 search results, 18 observational studies were included. Some studies demonstrated a significant association between occupational exposure to inhalational anesthetics and spontaneous abortion, especially among professionals who work for longer periods and/or in an environment without gas scavenging/ventilation systems, which may favor the occurrence of abortion in this population. Due to considerable heterogeneity and limitations, it cannot be concluded whether an association exists between occupational exposure to anesthetics and the occurrence of abortion. However, more well-designed studies should be performed, especially in less economically developed countries that do not have access to quality anesthetic gas scavenging/ventilation systems, thereby bringing this issue into sharp focus. This review highlights the need for scientific knowledge in this area and the extensive use of scavenging equipment and in the workplace to minimize exposure and reduce the risk of abortion.

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.

Neuroendocrine, epigenetic, and intergenerational effects of general anesthetics

The progress of modern medicine would be impossible without the use of general anesthetics (GAs). Despite advancements in refining anesthesia approaches, the effects of GAs are not fully reversible upon GA withdrawal. Neurocognitive deficiencies attributed to GA exposure may persist in neonates or endure for weeks to years in the elderly. Human studies on the mechanisms of the long-term adverse effects of GAs are needed to improve the safety of general anesthesia but they are hampered not only by ethical limitations specific to human research, but also by a lack of specific biological markers that can be used in human studies to safely and objectively study such effects. The latter can primarily be attributed to an insufficient understanding of the full range of the biological effects induced by GAs and the molecular mechanisms mediating such effects even in rodents, which are far more extensively studied than any other species. Our most recent experimental findings in rodents suggest that GAs may adversely affect many more people than is currently anticipated. Specifically, we have shown that anesthesia with the commonly used GA sevoflurane induces in exposed animals not only neuroendocrine abnormalities (somatic effects), but also epigenetic reprogramming of germ cells (germ cell effects). The latter may pass the neurobehavioral effects of parental sevoflurane exposure to the offspring, who may be affected even at levels of anesthesia that are not harmful to the exposed parents. The large number of patients who require general anesthesia, the even larger number of their future unexposed offspring whose health may be affected, and a growing number of neurodevelopmental disorders of unknown etiology underscore the translational importance of investigating the intergenerational effects of GAs. In this mini review, we discuss emerging experimental findings on neuroendocrine, epigenetic, and intergenerational effects of GAs.

Toxic responses of the liver and kidneys following occupational exposure to anesthetic gases

This study was undertaken to determine whether exposure of operating room personnel to inhalation anesthetics, including nitrous oxide, isoflurane, and sevoflurane was associated with any hepatotoxic or nephrotoxic changes. Fifty-two operating room personnel and 52 non-exposed subjects were studied. A questionnaire pertaining to demographic characteristics and medical history of participants was completed. Fasting blood samples were taken from all subjects to measure the functional parameters of kidneys and liver. Biological monitoring was also performed to detect the urinary concentration of IAs. Urinary concentrations of nitrous oxide, isoflurane, and sevoflurane were found to be 175.8 ± 77.52, 4.95 ± 3.43, and 15.0 3± 16.06 ppm, respectively. The mean levels of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, gamma-glutamyltransferase, Alpha-glutathione-S-transferase, as well as the serum levels of kidney injury molecule-1, creatinine and calcium were significantly higher in the exposed group. Statistically significant associations were observed between exposure to inhalation anesthetics and the mean levels of aspartate aminotransferase, alanine aminotransferase, and gamma-glutamyltransferase, serum creatinine, kidney injury molecule-1, and calcium. Under the exposure scenario described in the present study, occupational exposure to inhalation anesthetics was associated with subtle, subclinical, pre-pathologic changes in the parameters of liver and kidneys. Additionally, Alpha-glutathione-S-transferase and kidney injury molecule-1 were found to be sensitive markers for early detection of subclinical changes in the parameters of kidney and liver function in subjects who are exposed to inhalation anesthetics.

Intergenerational Effects of Sevoflurane in Young Adult Rats

BACKGROUND

Sevoflurane administered to neonatal rats induces neurobehavioral abnormalities and epigenetic reprogramming of their germ cells; the latter can pass adverse effects of sevoflurane to future offspring. As germ cells are susceptible to reprogramming by environmental factors across the lifespan, the authors hypothesized that sevoflurane administered to adult rats could induce neurobehavioral abnormalities in future offspring, but not in the exposed rats themselves.

METHODS

Sprague-Dawley rats were anesthetized with 2.1% sevoflurane for 3 h every other day between postnatal days 56 and 60. Twenty-five days later, exposed rats and nonexposed controls were mated to produce offspring.

RESULTS

Adult male but not female offspring of exposed parents of either sex exhibited deficiencies in elevated plus maze (mean ± SD, offspring of both exposed parents vs. offspring of control parents, 35 ± 12 vs. 15 ± 15 s, P < 0.001) and prepulse inhibition of acoustic startle (offspring of both exposed parents vs. offspring of control parents, 46.504 ± 13.448 vs. 25.838 ± 22.866%, P = 0.009), and increased methylation and reduced expression of the potassium ion-chloride ion cotransporter KCC2 gene (Kcc2) in the hypothalamus. Kcc2 was also hypermethylated in sperm and ovary of the exposed rats. Surprisingly, exposed male rats also exhibited long-term abnormalities in functioning of the hypothalamic-pituitary-gonadal and -adrenal axes, reduced expression of hypothalamic and hippocampal Kcc2, and deficiencies in elevated plus maze (sevoflurane vs. control, 40 ± 24 vs. 25 ± 12 s, P = 0.038) and prepulse inhibition of startle (sevoflurane vs. control, 39.905 ± 21.507 vs. 29.193 ± 24.263%, P < 0.050).

CONCLUSIONS

Adult sevoflurane exposure affects brain development in male offspring by epigenetically reprogramming both parental germ cells, while it induces neuroendocrine and behavioral abnormalities only in exposed males. Sex steroids may be required for mediation of the adverse effects of adult sevoflurane in exposed males.

Maternal wellbeing and pregnancy outcomes in anaesthetic trainees

The importance of supporting and maintaining doctors’ health and wellbeing cannot be overstated. Combined with the undisputed status of work in medicine as both strenuous and stressful, pregnancy is a unique time during which the mother and unborn baby may be at risk of adverse outcomes.

A narrative literature review is presented with a focus on studies of relevance to pregnancy in anaesthesia trainees, however much of the evidence is drawn from studies involving anaesthetic consultants, trainees in other specialties and pregnant workers in general. After a brief exploration into historical concepts in occupational hazards and adverse pregnancy outcomes, further discussion ensues on more recent evidence in relation to specialist training (or ‘residency’), the impact of work stressors and maternal psychological state on pregnancy outcomes and attitudes towards pregnancy during specialist training. Finally, occupational guidelines are considered along with the rationale for ‘pregnancy-friendly’ workplaces and suggestions for future research in this area for both the profession and employers.

Genotoxicity of inhalational anesthetics and its relationship with the polymorphisms of GSTT1, GSTM1, and GSTP1 genes

Due to their wide applications, concern exists regarding possible genotoxic effects of inhalational anesthetics (IAs) among operating room personnel. This study was undertaken to examine genotoxic properties of co-exposure to nitrous oxide, sevoflurane, and isoflurane on induction of micronucleus (MN) and chromosomal aberrations (CAs) and to determine whether any associations exist between polymorphisms of GST genes and the level of genomic damage measured by MN and CAs assays. Sixty operating room personnel and 60 unexposed referent nurses were studied. The workers' exposure to the IAs was determined. DNA damage was evaluated by MN and CAs assays. Additionally, the GSTM1, GSTT1, and GSTP1 polymorphisms were detected. The mean concentrations of nitrous oxide, isoflurane, and sevoflurane were found to be 850.92 ± 919.78, 2.40 ± 0.86, and 0.18 ± 0.14 ppm, respectively. The frequency of MN and CAs in the exposed group was significantly higher than that of the non-exposed group. The frequency of MN was significantly higher in referent nurses with null GSTT1, compared to referent nurses with positive GSTT1. The frequency of MN was significantly higher in exposed individuals carrying the combined genotype of GSTT1 (-), GSTM1 (-), and GSTP1 AG as compared with subjects carrying a combination of GSTT1 (+), GSTM1 (+), and GSTP1 AA. Statistically significant associations were noted between exposure to the IAs, gender, and the combination of the three GSTs genotypes with MN frequency. These findings indicate that inhalation exposure to IAs induces genotoxic response and the polymorphisms of GSTs genes might modulate the effect of exposure to IAs on MN.

Waste anesthetic gas exposure and strategies for solution

As inhaled anesthetics are widely used, medical staff have inevitably suffered from exposure to anesthetic waste gases (WAGs). Whether chronic exposure to WAGs has an impact on the health of medical staff has long been a common concern, but conclusions are not consistent. Many measures and equipment have been proposed to reduce the concentration of WAGs as far as possible. This review aims to dissect the current exposure to WAGs and its influence on medical staff in the workplace and the environment, and summarize strategies to reduce WAGs.

Are female children more likely to be born to Indian anesthesiologists? – A nationwide survey

Context:

Exposure to medications (prescribed or over-the-counter) or exposure to chemicals (unintentional or occupational) during pregnancy have always been of great scientific concerns.

Aims:

This study aims to ascertain whether the recently documented offspring sex ratio (OSR) skew in medical literature is reproducible among our respondent population and how our respondents' characteristics relate to the OSR skew (if any) in our respondent population.

Settings and Design:

A survey questionnaire uploaded on the SurveyMonkey^® Online Portal.

Subjects and Methods:

The survey was completed by the Indian anesthesiologists about themselves and their spouses during the periconceptional periods of their offspring.

Statistical Analysis Used:

Analysis of variance for means and Chi-square test for proportions with P < 0.05 as statistically significant.

Results:

Respondents (irrespective of gender) who sired first-born or second-born male children were anyway more likely to sire male children as reflected in the personal sex ratios among all offspring sired by them, and similarly respondents (irrespective of gender) who sired first-born or second-born female children were anyway more likely to sire female children. Male parents were significantly more common to have worked in operating rooms around the time of conception of first-born or second-born children. As compared to female anesthesiologists, male anesthesiologists significantly reported that they were practicing inhalational induction of anesthesia more often around the conception of their second-born female children as compared to around the conception of their second-born male children.

Conclusions:

Practice of inhalational induction of anesthesia was reportedly more common among Indian male anesthesiologists during periconceptional period of their second-born female children.

Does exposure to inhalation anesthesia gases change the ratio of X-bearing sperms and Y-bearing Sperms? A worth exploring project into an uncharted domain

According to recent surveys performed in United States and India, anesthesia care providers were observed to have sired female offspring in a higher proportion than male offspring as their firstborn progeny; however, the reasons for the skew are not clear. Our hypothesis is that the underlying biological evidence may be elucidated by unraveling differences (if any) between the concentrations of X-bearing sperms and Y-bearing sperms in the semen samples obtained from males exposed to varied levels of anesthetics in their lifetimes. Therefore, the objectives of the envisaged study would be to conduct a three-stage investigative study on in-vitro human semen samples to determine (a) X-bearing sperms and Y-bearing sperms concentrations' ratio in male pediatric anesthesia care providers' semen samples, (b) changes in X-bearing sperms and Y-bearing sperms concentrations' ratios between the pre-rotation and post-rotation semen samples of male medical student volunteers/observers, and (c) changes in X-bearing sperms and Y-bearing sperms concentrations' ratios between the pre-operative and post-operative day-3 semen samples of male patients presenting for outpatient procedures under inhalational anesthesia. The expected outcomes would be (a) linear and positive correlation of the anesthetic gas usage (exposure) with increased X-bearing sperms/Y-bearing sperms ratio in post-anesthesia day 3 sample as compared to the baseline preoperative sample, (b) linear and positive correlation of the anesthetic gas usage (exposure) with increased X-bearing sperms/Y-bearing sperms ratio in post-rotation sample as compared to the baseline sample, and (c) observation of high X-bearing sperms/Y-bearing sperms ratio in the pediatric anesthesia care providers. In summary, effects (if any) of occupational or personal exposure to inhalational anesthetic gases on the X-bearing sperms and Y-bearing sperms ratio is a worthy project wherein lots of questions that have arisen over decades could find the path to their definitive answers, based on envisaged laboratory investigations into this uncharted domain.

Effect of bispectral index versus end-tidal anesthetic gas concentration-guided protocol on time to tracheal extubation for halothane-based general anesthesia

BACKGROUND AND AIMS

Early extubation is a desirable goal after general anesthesia. Very few studies have compared the effect of bispectral index (BIS) monitoring versus standard end-tidal anesthetic gas (ETAG) concentration monitoring on tracheal extubation time for halothane-based anesthesia. The aim of this study was to compare the effect of BIS versus ETAG-guided anesthesia on time to tracheal extubation for halothane-based anesthesia in general surgical setting.

METHODS

This was a randomized, controlled double-blind study. Sixty patients with the American Society of Anesthesiologists physical status Class 1 or 2, receiving halothane-based general anesthesia were randomized to BIS-guided (n = 30) and ETAG-guided anesthesia (n = 30). Time to tracheal extubation was measured. In BIS group, BIS value was kept between 40 and 60 while in ETAG group; ETAG value was kept between 0.7 and 1.3 minimum alveolar concentration. The two groups were compared using Student's t-test, and P < 0.05 was considered statistically significant. Data were processed and analyzed using SPSS version 17 software.

RESULTS

Mean time to tracheal extubation was significantly longer in BIS group (9.63 ± 3.02 min) as compared to ETAG group (5.29 ± 1.51 min), mean difference 4.34 min with 95% confidence interval (3.106, 5.982) (P < 0.05).

CONCLUSION

In our study, the extubation time was significantly longer in BIS-guided anesthesia as compared to ETAG-guided anesthesia. ETAG monitoring promotes earlier extubation of patients as compared to BIS monitoring during halothane anesthesia.