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Biomedical subjects

S N Kales

Publications and source records attributed to S N Kales.

At least 19 recordsLinked to original sources

Firefighters' hearing: a comparison with population databases from the International Standards Organization.

We investigated firefighters' hearing relative to general population data to adjust for age-expected hearing loss. For five groups of male firefighters with increasing mean ages, we compared their hearing thresholds at the 50th and 90th percentiles with normative and age- and sex-matched hearing data from the International Standards Organization (databases A and B). At the 50th percentile, from a mean age of 28 to a mean age of 53 years, relative to databases A and B, the firefighters lost an excess of 19 to 23 dB, 20 to 23 dB, and 16 to 19 dB at 3000, 4000, and 6000 Hz, respectively. At the 90th percentile, from a mean age of 28 to a mean age of 53 years, relative to databases A and B, the firefighters lost an excess of 12 to 20 dB, 38 to 44 dB, 41 to 45 dB, and 22 to 28 dB at 2000, 3000, 4000, and 6000 Hz, respectively. The results are consistent with accelerated hearing loss in excess of age-expected loss among the firefighters, especially at or above the 90th percentile.

Adult↗

Spirometric surveillance in hazardous materials firefighters: does hazardous materials duty affect lung function?

We analyzed spirometry results for 351 male hazardous materials firefighters from 1996 to 1999 who underwent one or more annual medical surveillance/fitness for duty examinations: 276 (79%) technicians and 75 (21%) support members. Support members had a very limited potential for hazardous materials exposure and served as referents. In cross-sectional comparisons, the technicians' average forced vital capacity and forced expiratory volume in 1 second were either statistically better or not significantly different from that of the support members at all four examinations. Longitudinally, no statistically significant differences were seen for forced vital capacity. The mean percent of predicted forced expiratory volume in 1 second decreased by 3% for technicians (P = 0.029), support controls (P = 0.433), and the total cohort (P = 0.014). Although respiratory irritants are the most common type of exposure in hazardous materials releases, the results suggest that hazardous materials technicians do not lose pulmonary function at a more accelerated rate than support team firefighters.

Adult↗

Prospective study of hepatic, renal, and haematological surveillance in hazardous materials firefighters.

OBJECTIVES: To evaluate possible health effects related to work with hazardous materials as measured by end organ effect markers in a large cohort over about 2 years, and in a subcohort over 5 years. METHODS: Hepatic, renal, and haematological variables were analysed from 1996-98 in hazardous materials firefighters including 288 hazardous materials technicians (81%) and 68 support workers (19%). The same end organ effect markers in a subcohort of the technicians were also analysed (n=35) from 1993-98. Support workers were considered as controls because they are also firefighters, but had a low potential exposure to hazardous materials. RESULTS: During the study period, no serious injuries or exposures were reported. For the end organ effect markers studied, no significant differences were found between technicians and support workers at either year 1 or year 3. After adjustment for a change in laboratory, no significant longitudinal changes were found within groups for any of the markers except for creatinine which decreased for both technicians (p<0.001) and controls (p<0.01). CONCLUSIONS: Health effects related to work are infrequent among hazardous materials technicians. Haematological, hepatic, and renal testing is not required on an annual basis and has limited use in detecting health effects in hazardous materials technicians.

Adult↗

Correlates of fitness for duty in hazardous materials firefighters.

BACKGROUND AND METHODS: From a statewide medical examination program, we identified firefighters who were deemed unfit for duty by attending physicians (ATTENDING FAIL, n=9) and those who would have been disqualified by the application of selected numerical criteria from the 1997 National Fire Protection Association (NFPA) guidelines (NFPA FAIL, n=27) and criteria from a Medical Workshop (WORK FAIL, n=16). The subjects who were unfit for duty or failed numerical criteria were compared with those who were fit for duty and passed all objective criteria (FIT group, n=302). All subjects were given an overall morbidity rating by a board certified internist. Comparisons on two surrogate measures of fitness, VO(2) max predicted and predicted coronary heart disease (CHD) risk, were also performed. RESULTS: We found a significant tendency towards worse results (e.g. higher blood pressure or lower spirometric function) among the three FAIL groups compared with the FIT group. The FAIL groups shared only a small overlap, however, with the firefighters with the highest morbidity ratings, lowest predicted VO(2) max, and highest CHD risks. Increasing morbidity was associated with higher age, lower spirometric function, lower predicted VO(2) max, increasing cholesterol, greater BMI, and higher predicted 10 year CHD risk. CONCLUSIONS: Although the presence of a single serious or poorly controlled condition may render an individual unfit for safe performance as a firefighter, examination of our cohort suggests that multiple risk factor models or overall clinical assessments are superior means of identifying firefighters with poor health status and increased CHD risk.

Adult↗

Lung cancer and occupational risk factors in Greece.

This study estimated the proportion of lung cancer in Greece that was attributable to occupational exposure. Two hundred eighty-two patients with lung cancer and 494 controls were interviewed about their socioeconomic characteristics, sex, age, and occupational, smoking, and residential histories. Each subject was classified as exposed or unexposed to known occupational lung carcinogens. Because of the small number of females exposed, only males were included in the multivariate analyses. When the occupationally exposed subjects were compared with the unexposed subjects and an adjustment for smoking was made, the relative risk for lung cancer was 2.9 (95% confidence interval, 1.95-4.31). If 5% to 10% of the Greek population were occupationally exposed, the attributable risk would be 9.9% to 16.6%, respectively. Occupational exposures conferred an additional risk that was approximately threefold that of smoking alone. Risks increased in a dose-response fashion with increasing cigarette consumption.

Adult↗

Correlates of body mass index in hazardous materials firefighters.

We analyzed results from the medical examinations of 340 hazardous materials (HAZMAT) firefighters and observed the relationships between selected parameters and body mass index (BMI). Heights and weights were available for 98% of the subjects (333 of 340). The mean BMI was 28.9 +/- 4.1 kg/m2. Eighty-seven percent (290 of 333) of subjects were overweight (BMI > or = 25) and 34% (113 of 333) were obese (BMI > or = 30). Two percent (7 of 333) were morbidly obese (BMI > or = 39). For comparison purposes, we divided subjects into low (BMI < 27), medium (BMI 27 to < 30), and high (BMI > or = 30) BMI groups. The results demonstrated adverse associations between increasing BMI and resting blood pressures, forced vital capacity, alanine aminotransferase, aspartate aminotransferase, serum cholesterol, and overall morbidity scores. The high prevalence of overweight and obesity and the associated adverse health effects support the development and implementation of fitness-promotion programs for firefighters.

Adult↗

Methylene chloride poisoning in a cabinet worker.

More than a million workers are at risk for methylene chloride exposure. Aerosol sprays and paint stripping may also cause significant nonoccupational exposures. After methylene chloride inhalation, significant amounts of carbon monoxide are formed in vivo as a metabolic by-product. Poisoning predominantly affects the central nervous system and results from both carboxyhemoglobin formation and direct solvent-related narcosis. In this report, we describe a case of methylene chloride intoxication probably complicated by exogenous carbon monoxide exposure. The worker's presentation of intermittent headaches was consistent with both methylene chloride intoxication and carbon monoxide poisoning. The exposures and symptoms were corroborated by elevated carboxyhemoglobin saturations and a workplace inspection that documented significant exposures to both methylene chloride and carbon monoxide. When both carbon monoxide and methylene chloride are inhaled, additional carboxyhemoglobin formation is expected. Preventive efforts should include education, air monitoring, and periodic carboxyhemoglobin determinations. Methylene chloride should never be used in enclosed or poorly ventilated areas because of the well-documented dangers of loss of consciousness and death.

Adult↗

Fitness for duty evaluations in hazardous materials firefighters.

We analyzed results from the medical examinations of 340 hazardous materials firefighters and applied various objective standards in simulated fitness for duty determinations. Ten percent had elevated blood pressures, 13% had far visual acuity worse than 20/30 in one or both eyes, and 38% had abnormal audiometry. The strictest standards for resting blood pressure and corrected visual acuity would have failed 2% and 1% of the cohort, respectively. For audiometry, 0%-5% of the cohort would have failed, depending on the hearing requirements set. The strictest hearing standard did not allow for corrective devices so that few failures would be reversible. Visual and audiometric testing and measurement of resting blood pressure all have significant clinical yields. Studies of simulated firefighting are needed to establish minimum hearing requirements and determine whether corrective devices can be worn safely during duty.

Adult↗

Prognostic factors in patients with methanol poisoning.

OBJECTIVE: To identify prognostic factors in methanol poisoning and determine the effect of medical interventions on clinical outcome. METHODS: Retrospective review of all patients treated for methanol poisoning from 1982 through 1992 at The Toronto Hospital. Presenting history, physical examination, results of laboratory tests, medical interventions, and final outcomes after hemodialysis were abstracted. RESULTS: Of 50 patients treated for methanol poisoning, 18 (36%) died, 32 (64%) survived. Seven of the 32 survivors sustained visual sequelae (22%), the remaining 25 (78%) recovered completely. Patients presenting with coma or seizure had 84% (16/19) mortality compared to 6% (2/31) in those without (p < 0.001). Initial arterial pH < 7 was also associated with significantly higher mortality (17/19, 89% vs 1/31, 3%, p < 0.001). There were no differences in time from presentation to dialysis between survivors and fatalities (8.4 +/- 3.6 vs 7.6 +/- 3.5 hours, p = 0.47). The deceased patients had higher mean methanol concentration than the survivors (83 +/- 53 vs 41 +/- 25 mmol/L, p = 0.004). Subgroup analysis of 19 patients presenting with visual symptoms who survived showed prolonged acidosis (5.4 +/- 2.3 vs 3.0 +/- 2.1 hours, p = 0.06) in those with persistent visual sequelae. CONCLUSIONS: Coma or seizure on presentation and severe metabolic acidosis, in particular initial arterial pH < 7, are poor prognostic indicators in methanol poisoning. Survivors presented with lower methanol concentrations. Patients with residual visual sequelae had more prolonged acidosis than those with complete recovery. Future studies will be needed to confirm the effect of correction of acidosis on final clinical outcome.

Acidosis↗

Injuries caused by hazardous materials accidents.

STUDY OBJECTIVE: To describe exposures that prehospital and ED personnel may encounter as a result of hazardous material incidents. METHODS: Retrospective analysis of hazardous material incident reports from six district hazardous material teams in Massachusetts from their inception through May 1996. RESULTS: The chemicals most frequently involved were various hydrocarbons and corrosive materials. Chlorine derivatives were involved in 18% of all incidents and 23% of all incidents resulting in victims. Victims were produced by 47 of 162 (29%) incidents. Respiratory exposures were the most frequent type of exposure and resulted in the largest number of victims transported to a hospital. Overall 24 of 26 (92%) incidents with chemical exposures resulted in symptomatic victims and 33 of 35 (94%) incidents produced victims requiring hospital transport. Respiratory symptoms were the most frequent, both in the number of incidents where they were observed and the total number of victims with symptoms. CONCLUSION: Multiple victim transport to EDs from a single hazardous material incident is most likely to result from an inhalation exposure to a respiratory irritant. Information from descriptive studies should allow improved preparation for potential hazardous material victims.

Accidents↗

Medical surveillance of hazardous materials response fire fighters: a two-year prospective study.

Hazardous materials releases can cause substantial morbidity and mortality, and an increasing number of communities have developed hazardous materials (HAZMAT) teams to deal with such incidents. Little is known, however, about the health effects of chemical accidents on HAZMAT team participants. Baseline and periodic medical surveillance of all 40 fire fighters from the Metrofire Haz-mat team was conducted in 1992/1993 and 1995, respectively. A database on incidents responded to by the team during the study period was also developed. From June 1990 through April 1995, the team responded to a total of 34 hazardous materials incidents. No injuries to HAZMAT team members were reported. Few biochemical abnormalities were observed, and those that were could not be linked to specific exposures or incidents. Four individuals had abnormal audiometry on both occasions. There was a trend toward a lower percent predicted FEV1 for the entire group on follow-up: 106 +/- 13% vs 105 +/- 12%, P = 0.07. For fire fighters older than age 35 (n = 21), the percent predicted FEV1 was significantly lower at follow-up: 108 +/- 12% vs 106 +/- 14%, P = 0.01. The results suggest significant noise exposure and exposure to pulmonary irritants, which support the use of baseline and periodic audiometry and spirometry. The potential utility of other laboratory testing is also discussed.

Adult↗

Mechanisms of and facility types involved in hazardous materials incidents.

The purpose of this study was to systematically investigate hazardous materials (hazmat) releases and determine the mechanisms of these accidents, and the industries/activities and chemicals involved. We analyzed responses by Massachusetts' six district hazmat teams from their inception through May 1996. Information from incident reports was extracted onto standard coding sheets. The majority of hazardous materials incidents were caused by spills, leaks, or escapes of hazardous materials (76%) and occurred at fixed facilities (80%). Transportation-related accidents accounted for 20% of incidents. Eleven percent of hazardous materials incidents were at schools or health care facilities. Petroleum-derived fuels were involved in over half of transportation-related accidents, and these accounted for the majority of petroleum fuel releases. Chlorine derivatives were involved in 18% of all accidents and were associated with a wide variety of facility types and activities. In conclusion, systematic study of hazardous materials incidents allows the identification of preventable causes of these incidents.

Data Collection↗

Epidemiology of hazardous materials responses by Massachusetts district HAZMAT teams.

Hazardous materials releases can cause substantial morbidity and mortality, but very few studies have systemically investigated them. We analyzed responses by Massachusetts' six district hazardous materials (HAZMAT) teams from the time of their inception through February 1994. Spills, leaks, and other escapes of materials caused or contributed to 67 of 85 (79%) incidents. Transportation-related accidents accounted for 13 of 83 (16%), whereas the remainder of the releases occurred at fixed facilities. The chemicals most frequently involved were various hydrocarbons and corrosive materials. Most incidents (60 of 85 [70%]) had no reported injuries. Civilians were injured in 18 of 85 (21%) incidents; regular fire fighter and/or police were injured in eight of 85 (9%) incidents; and HAZMAT team members in one of 85 incidents (1%). Systematic study is needed to identify preventable causes of HAZMAT responses as well as ideas for better control of secondary health effects.

Accidents, Occupational↗

Are reference intervals for carboxyhemoglobin appropriate? A survey of Boston area laboratories.

CO is a leading cause of poisoning deaths in the US today. Treating physicians use the carboxyhemoglobin (COHb) % saturation to guide the diagnosis and treatment of CO intoxication. We conducted a telephone survey of hospitals and laboratories in the Boston area, focusing on methodology for COHb determination and accompanying COHb reference intervals. Among 130 facilities, 23 (18%) provide COHb analysis. All facilities that perform the COHb test utilize dedicated multiwave-length photometry. Reference intervals for COHb varied widely among facilities. Eight of 21 (38%) facilities give unacceptably high "normal intervals" for nonsmokers when compared with values available in the literature. Thirteen of 20 (65%) use reference intervals for smokers that are too low, and 3 of 20 (15%) use values that are too high. These reference values provided by the testing facilities may be misleading to the ordering physicians unfamiliar with background COHb saturations. This may lead to misdiagnoses, false reassurances, and perhaps less aggressive treatment than might be warranted. The results of this study argue for wider adoption of COHb reference intervals supported by the current literature.

Boston↗

Lead poisoning from mobilization of bone stores during thyrotoxicosis.

We describe a case of thyrotoxicosis accompanied by markedly elevated blood lead levels (initially 53 micrograms/dl) in a 37-year-old woman. No current source of lead exposure was found; the woman gave a history indicative of lead exposure as a child and as an adult 7 years previously, however. In addition, she was found to have markedly elevated bone lead levels, as measured by K-x-ray fluorescence (154 +/- 5 in the mid-tibia and 253 +/- 6 micrograms/g bone mineral in the patella), and an increased serum osteocalcin level (2.76 nmol/l), reflecting the increased bone turnover that often accompanies hyperthyroidism. During treatment with propylthiouracil, serial observations demonstrated a decline in serum osteocalcin that paralleled a decline in blood lead levels. Bone lead levels did not change appreciably. The patient also continued to have lingering neuropsychological symptoms consistent with chronic lead effects. We suggest that increased bone turnover accompanying thyrotoxicosis led to clinically significant lead poisoning in this patient, due to mobilization of accumulated bone lead stores acquired many years earlier. This phenomenon raises the general issue of more subtle forms of lead exposure from increased bone turnover states (e.g., osteoporosis).

Adult↗

Carboxyhemoglobin levels in patients with cocaine-related chest pain.

Carboxyhemoglobin (COHb) levels were measured in patients who came to an emergency department complaining of acute chest pain. For subjects not receiving prior oxygen therapy, those with cocaine-related chest pain (n = 10) had a higher mean COHb level than a comparison group (n = 28) with nonischemic chest pain (4.50 +/- 2.40 vs 2.73 +/- 0.66; p < 0.05). Four of the seven (57 percent) who smoked crack had COHb levels greater than 4.5 percent, while only one of six (17 percent) smokers of only tobacco had such a level. These findings suggest an additional mechanism, the formation of COHb, which could aggravate cocaine-induced cardiotoxicity.

Acute Disease↗