Substance misuse-related poisoning deaths, England and Wales, 1993–2016

Context

In recent years there has been an increase in the availability of ‘novel psychoactive substances (NPS)’ or ‘legal highs’. In turn, there is concern as to the risks these compounds pose as compared to those posed by traditionally misused substances such as illicit diamorphine (heroin), methadone, cocaine, and amfetamines.

Methods

We reviewed deaths where opiates/opioids, stimulants, hypnosedatives, hallucinogens, or volatile substances were mentioned on the death certificate in England and Wales, 1993–2016 as recorded on the Office for National Statistics drug poisoning deaths database. Deaths were analysed by year of registration of death, age, sex, intent, drug(s) involved, and the presence of alcohol (ethanol).

Results

There were 68,347 drug-related deaths in England and Wales (includes both licit and illicit substances), of which 15,457 were either coded as, or had mention of, drug dependent/non-dependent substance abuse on the death certificate. Opioids, particularly diamorphine/morphine and methadone, featured in most deaths. Diamorphine/morphine-related deaths (17,402) increased from 155 in 1993 to 981 in 2001, and then remained relatively stable until 2010 (791). Thereafter, annual numbers of deaths fell to 579 in 2012, but have since increased to 1,209 (2016). Deaths in the age group 20–29 years declined from 46% (1993), to 13% (2016), whereas in those aged 40–49 years the percentage of deaths increased from 13% (1993) to 33% (2016). Methadone was mentioned in 7,894 deaths (1993–2016). Annual numbers of such deaths increased from 206 to 437, 1993–7, then declined, but have since increased, reaching 413 in 2016. As to age, a similar pattern as to diamorphine/morphine-related deaths is apparent. Annual numbers of deaths involving cocaine (1993–2016: 3,342), reached 235 in 2008, declined, but have since increased (2011: 112, 2016: 371). Annual numbers of deaths involving methylenedioxyamfetamine/ methylenedioxyethamfetamine/ methylenedioxymetamfetamine (‘ecstasy’) (1993–2016: 853), have also increased steadily in recent years (2010; 8, 2016: 65). There were relatively few mentions of ‘novel stimulants’ (1993–2016: 386) on death certificates and such deaths have declined in recent years (2015: 88, 2016: 57). Mephedrone was most frequently mentioned (122), as was para-methoxyamfetamine/ para-methoxymetamfetamine (88). Conversely, although synthetic cannabinoids were mentioned infrequently (1993–2016: 37), such deaths have increased recently (2015: 8, 2016: 26).

Conclusions

Illicit diamorphine (heroin) and methadone continue to be the principal drugs of abuse involved in fatal poisonings in England and Wales. The increase in such deaths in recent years has been largely due to an increase in deaths amongst older users, although the role of potent synthetic opioids such as carfentanil is a cause for concern. Overall, stimulants and related compounds have been implicated in an increasing number of deaths annually. The impact of the plethora of NPS that have appeared in recent years on fatal poisonings may have been mitigated by legislation.

Sedentary Work by Females in Hot Environments

Performance by females on sedentary work tasks did not show meaningful decrement as a function of work place temperatures. In general, females showed less effect on performance in hot environments than did male subjects engaged in the same work activities.

Pharmacokinetics of Fluazifop-butyl in Human Volunteers II: Dermal Dosing

1 The absorption of the herbicide fluazifop-butyl (f-b), has been determined from plasma and urine measurements in groups of six male volunteers following dermal administration of 2.5, 25 and 250 ?g cm-2 from standardized formulations containing 0.05, 0.5 and 5.0% (w/v) fluazifop-butyl to a skin area of 800 cm2.

2 Urinary excretion rate of the principal metabolite fluazifop, following dosing with the 5% formulation, was described by a two-compartment pharmacokinetic model; the average elimination half-lives of initial and terminal phases were 18 h and approximately 70 h, respectively. For the other dose levels the elimination half-life was estimated to be 17 h; urine concentrations at later time points were too low to characterize a second compartment.

3 The estimated total fluazifop-butyl absorbed was 8.0, 3.4 and 1.6% of the applied dose for the 0.05, 0.5 and 5.0% formulations, respectively.

4 Up to 50% of the applied fluazifop-butyl was readily removed by skin washing and the majority of the remainder was transferred to clothing during the 24 h following application.

5 When six volunteers were given a daily dermal dose of the 0.5% formulation for five consecutive days, the plasma and urinary excretion kinetics of fluazifop could be accurately predicted by simple mathematical extrapolation of the kinetic data from the single exposure study at the equivalent daily dose.

6 It is concluded that fluazifop-butyl is only slowly and poorly absorbed through human skin and has a low potential to accumulate in man.

In Silico Prediction of Mechanism of Action for Cancer Therapeutics

Cancer is currently the second leading cause of death in the U.S. and is projected to become the principal cause in the near future. While radiation and surgery are common cancer treatment methods, chemotherapy remains a key treatment option, offering distinct advantages over other therapy options, especially in the management of metastasized tumors. Understanding the mechanism of action (MoA) of current and newly developed drugs is crucial to ongoing drug development research. Foreknowledge of how a candidate drug works can yield a wealth of information, including which cancers a drug may treat more effectively based on the susceptibility of the cancer to drugs with the same MoA. Previous studies concerning prediction of MoA have relied on costly experimental measurements as input for their predictions. We have developed an a priori quantitative structure-activity relationship (QSAR) for the in silico prediction of MoA without the need for experimental measurements. This model enables us to relate structural features of a chemical to its efficacy with a predictive accuracy of over 80 %, thus identifying the MoA of a candidate drug without costly, time-consuming experimental tests.

On meta-analyses of imaging data and the mixture of records

Neumann et al. (2010) aim to find directed graphical representations of the independence and dependence relations among activities in brain regions by applying a search procedure to merged fMRI activity records from a large number of contrasts obtained under a variety of conditions. To that end, Neumann et al., obtain three graphical models, justifying their search procedure with simulations that find that merging the data sampled from probability distributions characterized by two distinct Bayes net graphs results in a graphical object that combines the edges in the individual graphs. We argue that the graphical objects they obtain cannot be interpreted as representations of conditional independence and dependence relations among localized neural activities; specifically, directed edges and directed pathways in their graphical results may be artifacts of the manner in which separate studies are combined in the meta-analytic procedure. With a larger simulation study, we argue that their simulation results with combined data sets are an artifact of their choice of examples. We provide sufficient conditions and necessary conditions for the merger of two or more probability distributions, each characterized by the Markov equivalence class of a directed acyclic graph, to be describable by a Markov equivalence class whose edges are a union of those for the individual distributions. Contrary to Neumann et al., we argue that the scientific value of searches for network representations from imaging data lies in attempting to characterize large scaled neural mechanisms, and we suggest several alternative strategies for combining data from multiple experiments.

Use of ventricular stroke work index and ventricular function curves in assessing myocardial contractility

Cardiac output and cardiac index values are traditionally used by critical care nurses as indicators of myocardial contractility. Due to the incidence of compensatory tachycardia in many critically ill patients, however, the value of LVSWI as an indicator of myocardial contractility is enhanced, because the formula for its calculation does not emphasize the variable of heart rate. The advantages of using LVSWI are the following: It is easily calculated at the bedside by using an integrated hemodynamic software package or by using the formula provided. It is readily available to the nurse and indicates sensitive changes in myocardial function. When used in LV function curves in the nursing assessment of myocardial contractility of critically ill adults, its use can direct changes in fluid and pharmacologic interventions. Factors that affect ventricular end-diastolic pressure such as altered myocardial compliance or increased transmural pressure alters PCWP. Although LVSWI is not completely independent of these factors and may be less precise with altered PCWP, the LVSWI does enhance the data base used to manage patients with altered ventricular function. Ideal LVSWI values may not be achievable in patients with poor myocardial contractility; however, tracking the LVSWI provides sensitive and immediate feedback on the efficacy of pharmacologic intervention. Critical care nurses should use the LVSWI for any hemodynamically unstable patient whose myocardial contractility might be compromised. This information allows the nurse to optimize the patient's hemodynamic performance with a more accurate assessment of heart function.

Use of ventricular stroke work index and ventricular function curves in assessing myocardial contractility

Cardiac output and cardiac index values are traditionally used by critical care nurses as indicators of myocardial contractility. Due to the incidence of compensatory tachycardia in many critically ill patients, however, the value of LVSWI as an indicator of myocardial contractility is enhanced, because the formula for its calculation does not emphasize the variable of heart rate. The advantages of using LVSWI are the following: It is easily calculated at the bedside by using an integrated hemodynamic software package or by using the formula provided. It is readily available to the nurse and indicates sensitive changes in myocardial function. When used in LV function curves in the nursing assessment of myocardial contractility of critically ill adults, its use can direct changes in fluid and pharmacologic interventions. Factors that affect ventricular end-diastolic pressure such as altered myocardial compliance or increased transmural pressure alters PCWP. Although LVSWI is not completely independent of these factors and may be less precise with altered PCWP, the LVSWI does enhance the data base used to manage patients with altered ventricular function. Ideal LVSWI values may not be achievable in patients with poor myocardial contractility; however, tracking the LVSWI provides sensitive and immediate feedback on the efficacy of pharmacologic intervention. Critical care nurses should use the LVSWI for any hemodynamically unstable patient whose myocardial contractility might be compromised. This information allows the nurse to optimize the patient's hemodynamic performance with a more accurate assessment of heart function.

Task performance in heat: a review

A wide array of variable conditions, tasks, subject populations, etc., have been included in studies that have produced data on perceptual motor performance in the heat. This paper uses a methodology for comparing these studies, regardless of the inherent differences, which allows determination of whether thermal effects are dominant enough to persist through diverse combinations of variables. Approximately 160 individual studies of perceptual motor performance reported in the literature were summarized based on thermal level, duration of exposure and the type of task performed. Results indicated no dominant effect of duration of exposure to the heat and no dominant effect of thermal level on mental/cognitive tasks. For perceptual motor tasks other than very simple or mental tasks, an onset of performance decrement was noted in the 30-33 degrees C WBGT range of temperature. This temperature level is consistent with the Recommended Exposure Limits for work in the heat at low levels of metabolic heat.

The predictive accuracy of in vitro measurements for the dermal absorption of a lipophilic penetrant (fluazifop-butyl) through rat and human skin

The predictive accuracy of in vitro measurements in estimating dermal absorption has been evaluated in rat and human skin using fluazifop-butyl (FB), a lipophilic model compound, at dosage rates of 2.5, 25, and 250 micrograms/cm2. In vitro studies used rat and human epidermal membranes mounted in static diffusion cells with radiolabeled FB and receptor fluids of 50% aqueous ethanol (Aq Et), 6% polyethylene glycol 20 oleyl ether in saline (PEG), or tissue culture medium (TCM). In vivo rat studies with radiolabeled FB were carried out to parallel previously published human volunteer studies. For rat skin, in vitro measurements with all types of receptor fluid provide an adequate prediction (generally within a factor of 3) of in vivo absorption. Absorption data for human epidermal membranes with a receptor fluid of Aq Et were adequately predictive of the in vivo absorption. In contrast, membranes with PEG or TCM significantly underestimated the in vivo absorption. The results support the conclusion that in vitro studies are useful to predict in vivo dermal absorption in rat and man, when appropriate receptor fluids are used.

Modelling dermal pharmacokinetics using in vitro data. Part I. Fluazifop-butyl in the rat

The pharmacokinetics of the herbicide fluazifop-butyl have been determined in female rats following oral and intravenous dosing, and described by a mathematical model. Penetration of fluazifop-butyl through epidermal membranes has been determined using three different receptor fluids. It is demonstrated how this in vitro absorption data can be used with a pharmacokinetic model derived from oral and i.v. dosing studies to predict plasma concentrations and urinary excretion profiles following dermal dosing. Model predictions are compared with experimental measurements and found to be in good agreement.

Modelling dermal pharmacokinetics using in vitro data. Part II. Fluazifop-butyl in man

In a previous paper it was demonstrated that dermal absorption of the herbicide fluazifop-butyl in the rat could be modelled by combining a knowledge of the pharmacokinetics following intravenous and oral dosing with in vitro measurements of dermal absorption. This paper demonstrates the validation of a similar model for the dermal absorption of fluazifop-butyl in man. Pharmacokinetic parameters derived from an oral dosing study are combined in a mathematical model with in vitro measurements of dermal absorption of fluazifop-butyl. Model predictions of the rate and extent of dermal absorption of fluazifop-butyl are compared with the results of dermal absorption studies in human volunteers. Good agreement is found between the model predictions and the experimental measurements. These results have implications for improved risk assessment. The model provides a tool for risk assessment based on both internal dose (e.g. peak plasma concentration, plasma area under the curve) as well as total absorbed dose. However, further work is required to evaluate whether the same techniques are applicable to a wider range of compounds.

Further validation of an in vitro method to reduce the need for in vivo studies for measuring the absorption of chemicals through rat skin

Current requirements for the registration of agrochemicals, particularly in the U.S.A., often require the provision of dermal absorption data. In this process the rat is often used and complex in vivo studies, using large numbers of animals, are performed. We have compared the data obtained from in vivo and in vitro dermal absorption studies using eight pesticides with a range of physicochemical properties. Measurements were made of the 14C-labeled pesticides which could be washed from the skin, were associated with (on/in) skin, or absorbed through the skin following dermal applications in vivo and in vitro at various time points over a 24-hr exposure period. Good agreement was found between the amounts washed from and associated with the skin in vivo and in vitro. Over the time period 4-24 hr after application the in vitro experiments predicted the in vivo absorption within a factor of 2-3. These results show that, with a range of pesticide molecules, the in vitro method accurately predicted in vivo absorption supporting the utilization of the in vitro method for risk assessment from exposure to pesticides and other chemicals.

Detection and identification of volatile substances by headspace capillary gas chromatography to aid the diagnosis of acute poisoning

Headspace gas chromatography with split flame-ionization-electron-capture detection is a simple method of screening for a wide range of volatile substances in biological fluids. A 60 m x 0.53 mm i.d. thick-film (5 microns) fused-silica capillary coated with SPB-1 (Supelchem) with split flame-ionization-electron-capture detection provides a valuable alternative to packed columns in this work. Most commonly abused compounds, including many with very low boiling-points such as bromochlorodifluoromethane (BCF), butane, dimethyl ether, FC 11, FC 12, isobutane and propane, can be retained and differentiated at an initial column temperature of 40 degrees C followed by programming to 200 degrees C. The total analysis time is 26 min. Retention and detector response data were generated for 244 compounds. Good peak shapes are obtained for polar analytes such as ethanol and injections of up to 0.30 cm3 of headspace can be performed with no discernable loss of efficiency. The sensitivity is thus at least as good as that attainable with packed columns. Of the commonly encountered compounds, only isobutane-methanol and paraldehyde-toluene are at all difficult to differentiate. Quantitative measurements can be performed either isothermally or by using the temperature programme.

An introduction to the clinical toxicology of volatile substances

Acute poisoning with organic solvents and other volatile compounds now usually follows deliberate inhalation (volatile substance abuse) or ingestion of these compounds. Solvents from adhesives, typewriter correction and dry cleaning fluids, cigarette lighter refills (butane) and aerosol propellants are commonly abused. The major risk is that of sudden death. Arrhythmias leading to cardiac arrest are thought to cause most deaths, but anoxia, respiratory depression and vagal stimulation leading to cardiac arrest may also contribute, as may indirect causes such as aspiration of vomit or trauma. In the United Kingdom (UK), 3.5 to 10% of young people have at least experimented with volatile substance abuse and mortality is more than 100 per annum. The products abused are cheap and readily available despite legislation designed to limit supply. Volatile substance abuse is not illegal and only a minority of abusers are known to progress to heavy alcohol or illicit drug use. Prevention of abuse by education, not only of children but also of parents, teachers, retailers and health care workers, is important in limiting the problem. However, volatile substance abuse-related deaths are still increasing in the UK despite many measures aimed at prevention. Clinically, volatile substance abuse is characterised by a rapid onset of intoxication and rapid recovery. Euphoria and disinhibition may be followed by hallucinations, tinnitus, ataxia, confusion, nausea and vomiting. It is important not to further alarm the patient if signs of serious toxicity are present, since a cardiac arrest may be precipitated. Further exposure should be prevented and the patient resuscitated and given supplemental oxygen if necessary. Cardiac arrhythmias should be treated conventionally and respiratory failure managed supportively. Long term exposure to n-hexane is associated with the development of peripheral neuropathy, while prolonged abuse (notably of toluene or chlorinated solvents) can cause permanent damage to the central nervous system, heart, liver, kidney and lungs. Knowledge of the routes of absorption, distribution and excretion of volatile compounds, and of the rates governing these processes, is important in understanding the rate of onset, intensity and duration of intoxication, and rate of recovery after volatile substance abuse. In addition, such knowledge is helpful when the clinician is attempting to interpret the results of toxicological analyses performed on samples (blood, other tissues, urine) from such patients. Many volatile substances are partly metabolised, the metabolites being eliminated in exhaled air or in urine. Although metabolism normally results in detoxification, enhanced toxicity may also result as with carbon tetrachloride, chloroform, dichloromethane, n-hexane, trichloroethylene and possibly halothane.(ABSTRACT TRUNCATED AT 400 WORDS)

Analytical toxicology

1. Major advances in analytical toxicology followed the introduction of spectroscopic and chromatographic techniques in the 1940s and early 1950s and thin layer chromatography remains important together with some spectrophotometric and other tests. However, gas- and high performance-liquid chromatography together with a variety of immunoassay techniques are now widely used. 2. The scope and complexity of forensic and clinical toxicology continues to increase, although the compounds for which emergency analyses are needed to guide therapy are few. Exclusion of the presence of hypnotic drugs can be important in suspected 'brain death' cases. 3. Screening for drugs of abuse has assumed greater importance not only for the management of the habituated patient, but also in 'pre-employment' and 'employment' screening. The detection of illicit drug administration in sport is also an area of increasing importance. 4. In industrial toxicology, the range of compounds for which blood or urine measurements (so called 'biological monitoring') can indicate the degree of exposure is increasing. The monitoring of environmental contaminants (lead, chlorinated pesticides) in biological samples has also proved valuable. 5. In the near future a consensus as to the units of measurement to be used is urgently required and more emphasis will be placed on interpretation, especially as regards possible behavioural effects of drugs or other poisons. Despite many advances in analytical techniques there remains a need for reliable, simple tests to detect poisons for use in smaller hospital and other laboratories.

Sample handling and storage for the quantitative analysis of volatile compounds in blood: the determination of toluene by headspace gas chromatography

The problems associated with the handling and storage of blood samples for the analysis of toluene in toxicological casework using headspace gas chromatography have been investigated. Significant losses of toluene and the internal standard, ethylbenzene, from solution may be observed during handling. Toluene may be lost into the headspace above the blood in a storage container while such headspaces can also be detrimental, leading to the formation of n-hexanal, a possible interference with the assay. Large differences in the stability of toluene were seen for blood samples in different types of storage container. Storage containers in which the sample was only in contact with glass, teflon, or aluminum foil were most satisfactory. It is recommended that blood samples should be stored in appropriate containers with minimum headspace under cold conditions (4 degrees C). Transfers of blood should also be made at cold temperatures. The applicability of these guidelines to the analysis of other volatile compounds is discussed.

In vitro absorption of some o-phthalate diesters through human and rat skin

The absorption of undiluted phthalate diesters [dimethyl phthalate (DMP), diethylphthalate (DEP), dibutyl phthalate (DBP) and di-(2-ethylhexyl)phthalate (DEHP)] has been measured in vitro through human and rat epidermal membranes. Epidermal membranes were set up in glass diffusion cells and their permeability to tritiated water measured to establish the integrity of the skin before the phthalate esters were applied to the epidermal surface. Absorption rates for each phthalate ester were determined and a second tritiated water permeability assessment made to quantify any irreversible alterations in barrier function due to contact with the esters. Rat skin was consistently more permeable to phthalate esters than the human skin. As the esters became more lipophilic and less hydrophilic, the rate of absorption was reduced. Contact with the esters caused little change in the barrier properties of human skin, but caused marked increases in the permeability to water of rat skin. Although differences were noted between species, the absolute rates of absorption measured indicate that the phthalate esters are slowly absorbed through both human and rat skin.

Comparison of the in vivo and in vitro percutaneous absorption of a lipophilic molecule (cypermethrin, a pyrethroid insecticide)

The absorption of a pyrethroid insecticide, cypermethrin, through rat skin has been measured both in vitro and in vivo. Cypermethrin did not penetrate in vitro through whole skin but did penetrate epidermal membranes. The in vitro absorption was influenced by the choice of receptor fluid in the glass diffusion cell. There was good agreement between in vivo and in vitro data using 50% aqueous ethanol, 6% Volpo 20, or total calf serum receptor fluids. Rat epidermal membranes in vitro were more than 20 times more permeable to cypermethrin than human epidermal membranes, indicating that cypermethrin would be less readily absorbed in humans than in the rat. The percutaneous absorption in vitro technique using epidermal membranes was successfully used with this lipophilic chemical to predict the in vivo absorption in the rat.

The prediction of temperatures and heat stress limits in the workplace with natural ventilation

This paper presents a simple procedure for using the climatic factors reported by weather bureaus to predict levels of heat stress and conditions of risk in the workplace. For an aluminum reduction plant with natural ventilation, the study showed that the air temperature inside followed the same pattern of annual changes as the normal maximum ambient temperature outside the building. The Wet Bulb Globe Temperature (WBGT) was correlated significantly with air temperature (ta). With limited measurements, WBGT was predicted for the entire year at different locations in the shop.

Deaths from abuse of volatile substances: a national epidemiological study

A survey of the United Kingdom detected 282 deaths from abuse of volatile substances during 1971-83. Deaths appeared to have increased in the most recent years, reaching 80 in 1983. Age at death ranged from 11 to 76 years but most deaths (72%) occurred under 20 years. Ninety five per cent of the subjects were male, and in 1983 deaths from volatile substance abuse accounted for 2% of all deaths in males aged 10-19. All areas of the United Kingdom were affected, the rates being highest in Scotland and urban areas. All social classes were affected, though rates were highest in social class V and the armed forces. The volatile substances abused were gas fuels (24%), mainly butane; aerosol sprays (17%); solvents in glues (27%); and other volatile substances, such as cleaning agents (31%). In 51% of cases death was attributed to the direct toxic effects of the substance abused, in 21% to plastic bag asphyxia, in 18% to inhalation of stomach contents, and in 11% to trauma. Deaths associated with the abuse of glues were more likely to be traumatic, but all substances appeared capable of killing directly by their toxic effects, probably by a cardiac mechanism. Only a small proportion of deaths (6%) were due to the abuse of glues among children under 16; hence current attempts to limit access of children to glues will probably have little impact on overall mortality.

Measurement of dextropropoxyphene and nordextropropoxyphene in biological fluids

Detection, identification and measurement of dextropropoxyphene and its principal plasma metabolite, nordextropropoxyphene, can be important in the diagnosis of acute poisoning. A combination of thin-layer chromatography (TLC) and gas-liquid chromatography (GLC) of solvent or solid-phase extracts of urine or gastric contents usually serves to detect these and many other compounds, and an homogeneous enzyme immunoassay (EMIT-DAU) is also available for dextropropoxyphene. Measurement of dextropropoxyphene by GLC is complicated by the instability of this compound under certain conditions. However, a relatively polar stationary phase such as Carbowax 20M together with nitrogen-selective detection can give adequate sensitivity and selectivity for the measurement of the plasma concentrations attained after overdosage. High-performance liquid chromatography (HPLC) has not been widely applied in the assay of dextropropoxyphene and nordextropropoxyphene since these compounds have no pronounced ultraviolet absorption or fluorescence spectra. However, electrochemical oxidation detection can be used with a silica column/non-aqueous ionic eluent system. This gives good selectivity and sensitivity, and can facilitate the measurement of both compounds in plasma specimens after single oral dosage.

The role of the laboratory in the investigation of solvent abuse

1 A wide range of compounds which may be abused by inhalation such as butane, the halons, 1,1,1-trichloroethane, trichloroethylene and toluene can be detected and identified in blood specimens by means of headspace gas chromatography. Quantitative analysis of a number of the less volatile compounds of interest may also be accomplished. 2 The measurement of the urinary concentrations of benzoic and hippuric acids (metabolites of toluene) and of the toluric acids (metabolites of the xylenes) by high performance liquid chromatography may provide useful information. In general, a hippurate/creatinine ratio of greater than 1 is indicative of recent toluene exposure. 3 Analysis of the product abused by vapor-phase infra-red spectrophotometry and/or gas chromatography may also be valuable, especially since manufacturers' data as to the constituents of a given product are not always accurate. 4 Toxicological analyses can provide clinically valuable diagnostic information where inhalational abuse of volatile substances is suspected, and provide the only unequivocal means of defining the agent(s) abused by a given population.

An investigation of 140 deaths associated with volatile substance abuse in the United Kingdom (1971-1981)

1 In the UK, from 1971 to 81, 140 deaths associated with volatile substance abuse (VSA) were identified from press reports and a variety of other sources. Data about each death were obtained from inquest proceedings, post-mortem and toxicological reports, and death certificates. 2 Based on the year 1981, in which 39 deaths occurred, VSA deaths accounted for over 1% of deaths from all causes, and nearly 2% of deaths from injury and poisoning in males aged 10-19 years. 3 The median age was 16.8 years (range 11-63), and 79% were under age 20. The male to female ratio was 13:1. 4 Death rates were highest in conurbations, and in Scotland, Northern Ireland and Northern England. Deaths tended to be more frequent among manual social classes but this association was not marked. 5 The chief substances were butane (28%), solvents in adhesives (23%), other solvents (26%), aerosols (15%) and fire extinguishing agent (5%). Solvents in adhesives were more important with increasing age. 6 Most deaths occurred alone, at home. In about 41% of cases, death appeared to be only indirectly associated with VSA (trauma 8%, plastic bag over head 19%, and inhalation of stomach contents 14%). In 49% death was attributed to the direct toxic effects of the substance; this proportion was highest with aerosols and lowest with solvents in adhesives. 7 The implications of these findings for prevention, monitoring and research are discussed.

Suspected solvent abuse in cases referred to the Poisons Unit, Guy's Hospital, July 1980-June 1981

1 From July 1980 to June 1981, requests for information as to management or prognosis were received concerning 324 patients (219 male, 91 female) aged 3-31 y (median 15 y) in whom 'solvent abuse' was suspected.

2 The principal symptoms reported were unconsciousness (37), drowsiness (62), 'collapse' (7), convulsions (6), ataxia (35), chest pain (9), nausea/vomiting (20), renal impairment (3) and behavioural disturbances (84). At least 105 patients were admitted to hospital, and 1 was dead on arrival.

3 The products abused in 290 clinically diagnosed cases were: adhesives (214), correcting fluids (23), chlorinated solvents (17), fuel gases (18), petrol (5), BCF fire extinguishing agent (5) and others (17). The co-ingestion of alcohol or other drugs was suspected in only 27 cases.

4 Specimens of blood and/or urine were received for analysis from 117 patients. The clinical diagnosis of solvent abuse was confirmed in 71 cases and solvents were detected in 2 further instances. Ethanol/other drugs were detected in 18 instances, either together with solvent(s) (9) or alone (9), although no compounds were detected in the remaining 35 cases.

5 Toluene (and/or raised urinary hippurate/creatinine ratio) was detected in 52 of the analyses, 1,1,1-trichloroethane in 14 and trichloroethylene (and/or trichloroethanol) in 12. Ethanol was detected in 7 instances, and other drugs (principally benzodiazepines) in 13.

6 Although the presenting symptoms and outcome were usually unremarkable, these results emphasise that some patients can develop serious illness such as collapse or convulsions, which may prove fatal, while chronic solvent abuse can be associated with renal impairment.

Detection and identification of volatile organic compounds in blood by headspace gas chromatography as an aid to the diagnosis of solvent abuse

A gas chromatographic method has been developed for the detection and identification of some volatile organic compounds in whole blood, plasma or serum. After incubation of the sample (200 microliters) together with the internal standard solution in a sealed vial, a portion of the headspace is analysed using a 2-m glass column packed with 0.3% (w/w) Carbowax 20M on Carbopack C, 80-100 mesh. The column oven, after a 2-min isothermal period, is programmed from 35 to 175 degrees C at 5 degrees/min and held for 8 min. The effluent is monitored by both flame-ionisation and electron-capture detection, and peak assignment is by means of retention time and relative detector response. The method has proved applicable to the detection of bromochlorodifluoromethane, n-butane, carbon tetrachloride, chlorobutanol, cryofluorane (Halon 114), dichlorodifluoromethane (Halon 12), ethyl acetate, halothane, isobutane, isopropanol, isopropyl nitrate, methyl ethyl ketone, propane, tetrachloroethylene, toluene, 1,1,1-trichloroethane, 2,2,2-trichloroethanol, trichloroethylene and trichlorofluoromethane (Halon 11) in blood specimens obtained from patients suspected of abusing these agents.

Comparison between male and female subjective estimates of thermal effects and sensations

Thirty-one male subjects aged between 18 and 40 years and 15 female subjects aged between 18 and 24 years were used to compare male and female subjective estimates of the effect of heat on thermal sensation, drowsiness, boredom and fatigue. The subjects were exposed to climatic conditions between 74 degrees and 110 degrees F (23.3 degrees and 43.3 degrees C) Wet Bulb Globe Temperature (WBGT) while performing perceptual-motor tasks. Linear regression equations relating thermal sensation and ambient temperature were developed. These equations showed that the preferred temperature for males (71.6 degrees F (22 degrees C) WBGT) is significantly lower than that for females (77.1 degrees F (25 degrees C) WBGT). Females tend to feel more uncomfortable than males at both high and low temperature extremes. The subjective responses of thermal sensation take the same pattern as the subjective estimates of physiological responses to heat. Subjective estimates of thermal sensation in the heat relate directly to actual changes occurring in body temperature and heart rate. The subjective estimates by both males and females of drowsiness, boredom and fatigue form inverted U-curves when plotted against increasing temperature. The peaks of the inverted U or arousal curves for the two groups occur at 90 degrees F (32.2 degrees C) WBGT. The females reported higher levels of both drowsiness and boredom than the males at all temperatures, and the males reported higher fatigue than the females at the upper temperature levels.

Subjective estimates of physiological responses and perceptual-motor performance in the heat

A total of 31 male and 15 female subjects were selected for the present investigation. The subjects were all in excellent health and ranged in age between 18 and 40 years for the male group and 18 to 24 years for the female group. Four levels of temperature were used: 74 degrees , 90 degrees , 100 degrees and 110 degrees F Wet Bulb Globe Temperature (23.3 degrees , 32.2 degrees , 37.8 degrees and 43.3 degrees C WBGT respectively). The subjects performed four different perceptual-motor tasks. Results indicate that the subjective estimates of physiological responses to heat can be used as a good indicator of the actual changes occurring in physiological responses due to heat exposure. The subjects were more sensitive to changes occurring in body temperature than to changes occurring in the cardio vascular system. Under the extreme hot condition (110 degrees F (43.3 degrees C) WBGT) subjects underestimated the effect on their physiological responses. Perceptual-motor performance is poorly estimated by subjects during heat exposure.

Gas--liquid chromatographic retention indices of 296 non-drug substances on SE-30 or OV-1 likely to be encountered in toxicological analyses

The advent of the widespread use of selective detectors (electron capture detector, phosphorus/nitrogen dectector) for gas--liquid chromatography used in toxicological analyses has revealed the presence of hitherto unseen interfering materials. These substances may be conveniently grouped into (1), anti-oxidants; (2), putrefactive and endogenous compounds; (3), pesticides; (4), food additives, flavours and fragrances; (5) plasticisers, plastic additives and vulcanising agents and (6), scintillation reagents. To facilitate the identification of these materials, retention indices on the dimethyl silicone phases SE-30 or OV-1 have been compiled by the two laboratories to include 296 such compounds. Most gave single peaks, but some gave complex patterns indicating that they were mixtures of compounds. Of the 296 compounds, 14 did not give observable peaks, 8 gave 2 or 3 peaks and 44 gave more than 3 peaks. To determine the interlaboratory difference between retention index measurements, 17 compounds were chromatographed by both laboratories: the mean difference was +/- 13 retention index units with only one greater than +/- 50 retention index units. Examples of how these materials may be encountered during toxicological analyses are given. Data are also presented on compounds which have been used as internal standards.

Mepacrine pigmentation in systemic lupus erythematosus. New data from an ultrastructural, biochemical and analytical electron microscopic investigation

A case of mepacrine pigmentation occurring in a patient with systemic lupus erythematosus has been investigated by fluorescent light microscopy, gas--liquid chromatography and analytical electron microscopy. There is strong evidence for the presence of mepacrine itself within the typical granules, which have been shown by electron microscopy to be membrane bound and intracellular. Analytical electron microscopy also showed that the granules contain large quantities of iron and smaller quantities of sulphur.

Isodecrement curves for task performance in hot environments

This paper proposes a set of isodecrement curves for performance of perceptual motor tasks as a function of temperature and exposure time. Tasks studied include reaction time, mental tasks, vigilance, tracking, complex tasks, and combination of these tasks.

Abbreviated guidelines for heat stress exposure

A wide array of recommendations, rules and research results have been arregated into a simplified set of decision criteria for estimating threshold levels of heat stress. The WBGT is used as a basis, with appropriate modification for metabolic heat generated during work, velocity of air movement, state of acclimatization, amount of clothing (e.g., shorts, jackets, coats, enclosed suits), age, obesity, and sex. When WBGT levels for the person-task-environment combination are exceeded, initiation of appropriate engineering and work practices are indicated.

Damage risk: an evaluation of the effects of exposure to 85 versus 90 dBA of noise

The purpose of this study was to compare the damage risk of 85 and 90 dBA of white noise for equivalent full-day exposures. The damage risk of the two noise levels was determined by comparing the temporary threshold shift (TTS) of 12 subjects exposed to either 85 or 90 dBA of white noise for equivalent half- and full-day exposures. TTS was determined by comparing the pre- and postexposure binaural audiograms of each subject at 1, 2, 3, 4, 6, and 8 kHz. It was concluded that the potential damage risk, that is, hazardous effect, of 90 dBA is greater than 85 dBA of noise for equivalent full-day exposures. The statistical difference between the overall effects of equivalent exposures to 85 dBA as compared to 90 dBA of noise could not be traced to any one frequency. The damage risk of a full-day exposure to 85 dBA is equivalent to that of a half-day exposure to 90 dBA of noise. Within the limits of this study, TTSt was as effective as TTS2 for estimating the damage risk of noise exposure.

Salicylate removal by charcoal haemoperfusion in experimental intoxication in dogs:an assessment of efficacy and safety

The removal of salicylate by extracorporeal circulation of blood through a column of encapsulated activated charcoal (haemoperfusion) has been studied experimentally in intoxicated dogs (greyhounds). The average time taken to reduce the whole blood salicylate level to one-half of the initial equilibrium level in 30 kg dogs was 2 hrs. A half-life of 3 hrs is predicted for salicylate removal by haemoperfusion in a 70 kg man and this rate of removal is shown to be comparable to that reported for haemodialysis. No unacceptable adverse physiological, biochemical, or haematological effects were found to result from haemoperfusion. The possible use of this technique in the management of severe salicylate poisoning in man is discussed. Haemoperfusion is foreseen as providing a method of rapid removal of salicylate in circumstances where forced diuresis is contra-indicated or inadequate and haemodialysis is not readily available.

Heat stress limits for the sedentary worker

Performance on four sedentary tasks was monitored during temperatures of 85 degrees f, 95 degrees F, and 105 degrees F WBGT for work periods up to 2 hours. Results were compared with limits recommedned for occupational safety and health regulations. It is suggested that this limit is not a single line, but rather a range of temperture-time combinations. Further, man's compensating nature during short exposures supports a higher temperature limit for brief work bouts.