Effect of smoking cessation on chronic waterpipe smoke inhalation-induced airway hyperresponsiveness, inflammation, and oxidative stress.

Waterpipe smoking (WPS) prevalence is increasing globally. Clinical and laboratory investigations reported that WPS triggers impairment of pulmonary function, inflammation, and oxidative stress. However, little is known if smoking cessation (SC) would reverse the adverse pulmonary effects induced by WPS. Therefore, we evaluated the impact of WPS inhalation for 3 mo followed by 3 mo of SC (air exposure) compared with those exposed for either 3 or 6 mo to WPS or air (control) in C57BL/6 mice. To this end, various physiological, biochemical, and histological endpoints were evaluated in the lung tissue. Exposure to WPS caused focal areas of dilated alveolar spaces and foci of widening of interalveolar spaces with peribronchiolar moderate mixed inflammatory cells consisting of lymphocytes, macrophages, and neutrophil polymorphs. The latter effects were mitigated by SC. Likewise, SC reversed the increase of airway resistance and reduced the increase in the levels of myeloperoxidase, matrix metalloproteinase 9, granulocyte-macrophage colony-stimulating factor, tumor necrosis factor-α, interleukin (IL)-6, and IL-1ß in lung tissue induced by WPS. In addition, SC attenuated the increase of oxidative stress markers including 8-isoprostane, glutathione, and catalase induced by WPS. Similarly, DNA damage, apoptosis, and the expression of NF-κB in the lung induced by WPS inhalation were alleviated by CS. In conclusion, our data demonstrated, for the first time, to our knowledge, that SC-mitigated WPS inhalation induced an increase in airway resistance, inflammation, oxidative stress, DNA injury, and apoptosis, illustrating the benefits of SC on lung physiology.

COVID-19: smoke testing of surgical mask and respirators.

BACKGROUND: Fluid Resistant Surgical Masks have been implemented in UK personal protective equipment (PPE) guidelines for COVID-19 for all care sites that do not include aerosol-generating procedures (AGPs). FFP3 masks are used in AGP areas. Concerns from the ENT and plastic surgery communities out with intensive care units have questioned this policy. Emerging evidence on cough clouds and health care worker deaths has suggested that a review is required. AIMS: To test the efficacy of Fluid Resistant Surgical Mask with and without adaptions for respiratory protection. To test the efficacy of FFP and FFP3 regarding fit testing and usage. METHODS: A smoke chamber test of 5 min to model an 8-h working shift of exposure while wearing UK guideline PPE using an inspiratory breathing mouthpiece under the mask. Photographic data were used for comparison. RESULTS: The Fluid Resistant Surgical Mask gave no protection to inhaled smoke particles. Modifications with tape and three mask layers gave slight benefit but were not considered practical. FFP3 gave complete protection to inhaled smoke but strap tension needs to be 'just right' to prevent facial trauma. Facial barrier creams are an infection risk. CONCLUSIONS: Surgical masks give no protection to respirable particles. Emerging evidence on cough clouds and health care worker deaths suggests the implementation of a precautionary policy of FFP3 for all locations exposed to symptomatic or diagnosed COVID-19 patients. PPE fit testing and usage policy need to improve to include daily buddy checks for FFP3 users.

Effectiveness of a Voice Smoke Alarm Using the Child's Name for Sleeping Children: A Randomized Trial.

OBJECTIVES: To test maternal voice alarm effectiveness under residential conditions and determine whether personalizing the maternal voice alarm message with the child's first name improves effectiveness. STUDY DESIGN: Using a randomized, nonblinded, repeated measures design, we compared 3 maternal voice smoke alarms with respect to their ability to awaken 176 children 5-12 years old from stage 4 slow-wave sleep and prompt their performance of an escape procedure. A conventional residential high-frequency tone smoke alarm was used as a comparative reference. Children's sleep stage was monitored in a residence-like research setting. RESULTS: Maternal voice alarms awakened 86%-91% of children and prompted 84%-86% to escape compared with 53% awakened and 51% escaped for the tone alarm. A sleeping child was 2.9-3.4 times more likely to be awakened by each of the 3 voice alarms than the tone alarm. The median time to awaken was 156 seconds for the tone alarm and 2 seconds for each voice alarm. The proportions of children who awakened and escaped differed significantly between the tone alarm and each voice alarm, but no significant differences were found between each pair of the voice alarms, regardless of whether the child's first name was included in the alarm message. CONCLUSIONS: The maternal voice alarms significantly outperformed the tone alarm under residential conditions. Personalizing the alarm message with the child's first name did not increase alarm effectiveness. These findings have important implications for development of an effective and practical smoke alarm for children. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01169155.

SOCS-1 ameliorates smoke inhalation-induced acute lung injury through inhibition of ASK-1 activity and DISC formation.

Smoke inhalation leads to acute lung injury (ALI), a devastating clinical problem associated with high mortality. Suppressor of cytokine signaling-1 (SOCS-1) is a negative regulator of apoptosis and pro-inflammatory cytokine signaling, two major contributors to the pathogenesis of ALI. We have found that SOCS-1 protects lung epithelial cells from smoke-induced apoptosis through two mechanisms. One is that SOCS-1 enhances degradation of ASK-1 and diminishes cleavage of pro-caspase-3 to repress smoke-triggered apoptosis in lung epithelial cells. The other is that SOCS-1 represses smoke-triggered DISC formation through altering TRADD-caspase-8 interaction rather than TNFR-1-TRADD interaction or TNFR-1-TRAF-2 interaction. In conclusion, SOCS-1 relieves smoke inhalation-induced lung injury by repressing ASK-1 and DISC-mediated epithelium apoptosis.

Health benefits and costs of filtration interventions that reduce indoor exposure to PM2.5 during wildfires.

Increases in hospital admissions and deaths are associated with increases in outdoor air particles during wildfires. This analysis estimates the health benefits expected if interventions had improved particle filtration in homes in Southern California during a 10-day period of wildfire smoke exposure. Economic benefits and intervention costs are also estimated. The six interventions implemented in all affected houses are projected to prevent 11% to 63% of the hospital admissions and 7% to 39% of the deaths attributable to wildfire particles. The fraction of the population with an admission attributable to wildfire smoke is small, thus, the costs of interventions in all homes far exceeds the economic benefits of reduced hospital admissions. However, the estimated economic value of the prevented deaths exceed or far exceed intervention costs for interventions that do not use portable air cleaners. For the interventions with portable air cleaner use, mortality-related economic benefits exceed intervention costs as long as the cost of the air cleaners, which have a multi-year life, are not attributed to the short wildfire period. Cost effectiveness is improved by intervening only in the homes of the elderly who experience most of the health effects of particles from wildfires.

Risk factors associated with unintentional house fire incidents, injuries and deaths in high-income countries: a systematic review.

OBJECTIVE: To identify the distinguishing risk factors associated with unintentional house fire incidents, injuries and deaths. STUDY DESIGN: Systematic review. METHODS: A range of bibliographical databases and grey literature were searched from their earliest records to January 2016. To ensure the magnitude of risk could be quantified, only those study types which contained a control group, and undertook appropriate statistical analyses were included. A best evidence synthesis was conducted instead of a meta-analysis due to study heterogeneity. RESULTS: Eleven studies investigating a variety of risk factors and outcomes were identified. Studies ranged from medium to low quality with no high quality studies identified. Characteristics commonly associated with increased risk of house fire incidents, injuries and fatalities included: higher numbers of residents, male, children under the age of 5 years, non-working households, smoking, low income, non-privately owned properties, apartments and buildings in poor condition. Several risk factors were only associated with one outcome (eg, living alone was only associated with increased risk of injurious fires), and households with older residents were at increased risk of injurious fires, but significantly less likely to experience a house fire in the first place. CONCLUSIONS: This best evidence synthesis indicates that several resident and property characteristics are associated with risk of experiencing house fire incidents, injuries or death. These findings should be considered by the Fire and Rescue Services and others with a role in fire prevention. Future research should adopt robust, standardised study designs to permit meta-analyses and enable stronger conclusions to be drawn.

Home Fire Safety Practices and Smoke Detector Program Awareness in an Urban Pediatric Emergency Department Population.

OBJECTIVES: Risk factors for residential fire death (young age, minority race/ethnicity, and low socioeconomic status) are common among urban pediatric emergency department (ED) patients. Community-based resources are available in our region to provide free smoke detector installation. The objective of our study was to describe awareness of these resources and home fire safety practices in this vulnerable population. METHODS: In this cross-sectional study, a brief survey was administered to a convenience sample of caregivers accompanying patients 19 years of age or younger in an urban pediatric ED in Washington, DC. Survey contents focused on participant knowledge of available community-based resources and risk factors for residential fire injury. RESULTS: Five hundred eleven eligible caregivers were approached, and 401 (78.5%) agreed to participate. Patients accompanying the caregivers were 48% male, 77% African American, and had a mean (SD) age of 6.5 (5.9) years. Of study participants, 256 (63.8%) lived with children younger than 5 years. When asked about available community-based resources for smoke detectors, 240 (59.9%) were unaware of these programs, 319 (79.6%) were interested in participating, and 221 (55.1%) enrolled. Presence of a home smoke detector was reported by 396 respondents (98.7%); however, 346 (86.3%) reported testing these less often than monthly. Two hundred fifty-six 256 (63.8%) lacked a carbon monoxide detector, and 202 (50.4%) had no fire escape plan. Sixty-five (16%) reported indoor smoking, and 92 (22.9%) reported space heater use. CONCLUSIONS: In this urban pediatric ED population, there is limited awareness of community-based resources but high rates of interest in participating once informed. Whereas the self-reported prevalence of home smoke detectors is high in our study population, other fire safety practices are suboptimal.

[Modern aspects of the conservation and promotion of health of firefighters].

On the basis of complex hygienic studies there were determined conditions of the work of firefighters in liquidation of foci of fires at the incipient stage, identified the complex of toxic substances, their quantitative content in the area of the smoke of fires. The analysis of the etiological role of occupational factors in the shaping of the morbidity and the physiological and clinical manifestations, established indices of the risk for occupational and industrial-caused pathology have allowed to substantiate the relationship of a number of nosological forms associated with working conditions of firefighters. There was developed a system of preventive activities for the promotion and preservation of the health of firefighters, as well as a conceptual model for monitoring of working conditions and state of health.

Tiotropium bromide suppresses smoke inhalation and burn injury-induced ERK 1/2 and SMAD 2/3 signaling in sheep bronchial submucosal glands.

The effects of tiotropium bromide on ERK 1/2, SMAD 2/3 and NFκB signaling in bronchial submucosal gland (SMG) cells of sheep after smoke inhalation and burn injury (S + B) were studied. We hypothesized that tiotropium would modify intracellular signaling processes within SMG cells after injury. Bronchial tissues were obtained from uninjured (sham, n = 6), S + B injured sheep 48 h after injury (n = 6), and injured sheep nebulized with tiotropium (n = 6). The percentage (mean ± SD) of cells showing nuclear localization of phosphorylated ERK 1/2, pSMAD 2/3, and NFκB (p65) was determined by immunohistochemistry. Nuclear pERK 1/2 staining was increased in injured animals as compared to sham, (66 ± 20 versus 14 ± 9), p = 0.0022, as was nuclear pSMAD, 84 ± 10 versus 20 ± 10, p = 0.0022. There was a significant decrease in pERK 1/2 labeling in the tiotropium group compared to the injured group (31 ± 20 versus 66 ± 20, p = 0.013), and also a decrease in pSMAD labeling, 62 ± 17 versus 84 ± 10, p = 0.04. A significant increase for NFκB (p65) was noted in injured animals as compared to sham (73 ± 16 versus 7 ± 6, p = 0.0022). Tiotropium-treated animals showed decreased p65 labeling as compared to injured (35 ± 17 versus 74 ± 16, p = 0.02). The decrease in nuclear expression of pERK, pSMAD and NFκB molecules in SMG cells with tiotropium treatment is suggestive that their activation after injury is mediated in part through muscarinic receptors.

Protective Effects of Coenzyme Q10 on Testicular Histology in Rats Exposed via Chronic Mosquito Coil Smoke Inhalation.

OBJECTIVE: To determine the preventive effect of coenzyme Q10 (CoQ10) on the testicular histology of rats exposed chronically to mosquito coil smoke. STUDY DESIGN: Experimental study. Place and Duration of the Study: Department of Anatomy, Army Medical College/National University of Medical Sciences, Rawalpindi, Pakistan, from January to December 2020. METHODOLOGY: Thirty male Sprague Dawley rats were divided into three groups of 10 rats each. Group A was the healthy control. Group B rats were exposed to allethrin-based mosquito coil smoke for 12 weeks (4 hours/day). Group C rats received coenzyme Q10 (CoQ10, 10mg/kg/day) through oral gavage, in addition to 12 weeks of mosquito coil smoke exposure (4 hours/day). At the end of the study, testicular histology was compared among three groups including the germinal epithelium height, seminiferous tubule diameter, and testicular capsule thickness, while adjusting for the body weight variations among rats. RESULTS: The rats in Group B, exposed only to mosquito coil smoke showed testicular disruption, characterised by dilated seminiferous tubules (p <0.001), reduced germinal epithelial height (p <0.001), and thickened testicular capsule (p <0.007), as compared to the control group rats. However, the germinal epithelium height (p = 0.73) and testicular capsule thickness (p = 0.31) of rats receiving CoQ10 in addition to mosquito coil smoke inhalation were not significantly different from the control group. CONCLUSION: Prolonged inhalation of allethrin-based mosquito coil smoke can cause testicular disruption among rats. The oral CoQ10 administration can effectively prevent the histomorphological adverse effects on the testis among rats exposed to mosquito coil smoke. KEY WORDS: Allethrin, Coenzyme Q10, Germinal epithelium, Mosquito coil, Seminiferous tubules, Testicular capsule.

Occupational exposures and symptoms among firefighters and police during the carmel forest fire: the Carmel cohort study.

BACKGROUND: From 2 to 5 December 2010, Israel experienced the most severe forest fire In its history, resulting in the deaths of rescue workers. Little research exists on the health risks to emergency responders during forest fires, and there is no published research to date on occupational health among firefighters in Israel. OBJECTIVES: To describe the exposures experienced by emer gency responders to smoke, fire retardants and stress; the utilization of protective equipment; and the frequency of corresponding symptoms during and following the Carmel Forest fire. METHODS: A cohort of 204 firfighers and 68 police who took part in rescue and fire-abating activites during the Carmel Forest fire were recruited from a representative sample of participating stations throughout the country and interviewed regarding their activities during the fire and their coinciding symptoms. Unpaired two-sample t-test compared mean exposures and symptom frequency for firefighters and police. Chi-square estimates of OR and 95%CI are provided for odds of reporting symptoms, incurring injury or being hospitalied for various risk factors RESULTS: Of the study participants, 87% reported having at least one symptom during rescue work at the Carmel Forest fire,with eye irritation (77%) and fatigue (71%) being the most comon. Occupational stress was extremely high during the fire; the average length of time working without rest was 18.4 hours among firefighters. CONCLUSION: Firefighter and police were exposed to smoke and ocupational stress prolonged periods during the fire. Further research is needed on the residual health effects from exposure to forest fires among emergency responders, and to identify areas for improvement in health preparedness.

Purinergic receptor inhibition prevents the development of smoke-induced lung injury and emphysema.

Extracellular ATP acts as a "danger signal" and can induce inflammation by binding to purinergic receptors. Chronic obstructive pulmonary disease is one of the most common inflammatory diseases associated with cigarette smoke inhalation, but the underlying mechanisms are incompletely understood. In this study, we show that endogenous pulmonary ATP levels are increased in a mouse model of smoke-induced acute lung inflammation and emphysema. ATP neutralization or nonspecific P2R-blockade markedly reduced smoke-induced lung inflammation and emphysema. We detected an upregulation the purinergic receptors subtypes on neutrophils (e.g., P2Y2R), macrophages, and lung tissue from animals with smoke-induced lung inflammation. By using P2Y(2)R deficient ((-/-)) animals, we show that ATP induces the recruitment of blood neutrophils to the lungs via P2Y(2)R. Moreover, P2Y(2)R deficient animals had a reduced pulmonary inflammation following acute smoke-exposure. A series of experiments with P2Y(2)R(-/-) and wild type chimera animals revealed that P2Y(2)R expression on hematopoietic cell plays the pivotal role in the observed effect. We demonstrate, for the first time, that endogenous ATP contributes to smoke-induced lung inflammation and then development of emphysema via activation of the purinergic receptor subtypes, such as P2Y(2)R.

Wildland smoke exposure values and exhaled breath indicators in firefighters.

Smoke from forest fires contains significant amounts of gaseous and particulate pollutants. Firefighters exposed to wildland fire smoke can suffer from several acute and chronic adverse health effects. Consequently, exposure data are of vital importance for the establishment of cause/effect relationships between exposure to smoke and firefighter health effects. The aims of this study were to (1) characterize the relationship between wildland smoke exposure and medical parameters and (2) identify health effects pertinent to wildland forest fire smoke exposure. In this study, firefighter exposure levels of carbon monoxide (CO), nitrogen dioxide (NO2), and volatile organic compounds (VOC) were measured in wildfires during three fire seasons in Portugal. Personal monitoring devices were used to measure exposure. Firefighters were also tested for exhaled nitric oxide (eNO) and CO before and after their firefighting activities. Data indicated that exposure levels during firefighting activities were beyond limits recommended by the Occupational Exposure Standard (OES) values. Medical tests conducted on the firefighters also indicated a considerable effect on measured medical parameters, with a significant increase in CO and decrease in NO in exhaled air of majority of the firefighters.

Validity of smoke alarm self-report measures and reasons for over-reporting.

OBJECTIVES: Many residential fire deaths occur in homes with no or non-functioning smoke alarms (SAs). Self-reported SA coverage is high, but studies have found varying validity for self-report measures. The authors aim to: (1) determine over-reporting of coverage, (2) describe socio-demographic correlates of over-reporting and (3) report reasons for over-reporting. METHODS: The authors surveyed 603 households in a large, urban area about fire safety behaviours and then tested all SAs in the home. 23 participants who over-reported their SA coverage were telephoned and asked about why they had misreported. RESULTS: Full coverage was reported in 70% of households but observed in only 41%, with a low positive predictive value (54.2%) for the self-report measure. Most over-reporters assumed alarms were working because they were mounted or did not think a working alarm in a basement or attic was needed to be fully protected. CONCLUSIONS: If alarms cannot be tested, researchers or those counselling residents on fire safety should carefully probe self-reported coverage. Our findings support efforts to equip more homes with hard-wired or 10 year lithium battery alarms to reduce the need for user maintenance.

Igniting interest in prevention: using firefighter focus groups to inform implementation and enhancement of an urban canvassing program.

CONTEXT: Smoke alarm canvassing is recognized as an empirically based, effective intervention for increasing access to and the presence of smoke alarms in homes. OBJECTIVES: We sought to inform the implementation of an intervention designed to enhance an existing fire department smoke alarm canvassing program through an empirically grounded, participatory process. DESIGN: We conducted a series of focus groups with fire union leaders and firefighters involved with the canvassing program in 1 US city, shared the results with the participants, and presented the resulting recommendations to fire department leadership. SETTING: This research occurred in Baltimore, Maryland. PARTICIPANTS: Focus group participants included firefighters who participate in the Fire Department's smoke alarm canvassing program and representatives from the local firefighters' union. MAIN OUTCOME MEASURES: The focus groups sought to capture firefighters' experiences with and opinions about the canvassing program and how to improve it as well as challenges to canvassing work. RESULTS: We conducted 10 focus groups with 65 participants. Firefighters' perspectives on the canvassing program and their recommendations for improving it were expressed through 3 categories of themes concerning program management, canvassing challenges, and attitudes about the program and the community. We also discuss the process of presenting these findings and recommendations to the participants and the fire department leadership, and describe how implementation of some of the recommendations has progressed. CONCLUSIONS: Both the process and outcomes of this formative work inform how to develop and implement community-based public health interventions in real-world settings through academic-community partnerships. The findings also have implications for how canvassing programs are being implemented.

Do nuisance alarms decrease functionality of smoke alarms near the kitchen? Findings from a randomised controlled trial.

BACKGROUND: Many home fires begin in the kitchen. Kitchen smoke alarms are more likely to produce nuisance alarms, but few previous studies have examined the role of alarm sensor and battery types on the functionality of smoke alarms located nearest to the kitchen. METHODS: Data were analysed from a 2×2 factorial randomised controlled trial conducted in rural Iowa homes (n=628). Enrolled households were randomly assigned into one of four smoke alarm/battery combinations: ionisation/zinc, ionisation/lithium, photoelectric/zinc and photoelectric/lithium. Alarm functionality was determined using a smoke test. Alarm type and battery type were compared using an intent-to-treat analysis. Logistic regression was used to identify factors that might impact the functionality of smoke alarms located nearest to the kitchen 42 months after installation. RESULTS: Photoelectric alarms with lithium batteries had the highest rate of functionality (90.2%), whereas ionisation alarms with carbon/zinc batteries had the lowest (76.5%). Forty-two months following installation, 6.4% more of photoelectric alarms were functional than ionisation alarms, and 7.9% more of alarms with lithium batteries were functional than those with carbon/zinc batteries. Logistic regression revealed that when the indicator of nuisance alarms was included, the effect of alarm type became statistically insignificant and ionisation alarms were less likely to be functional at 42 months, partly due to increased nuisance alarms. CONCLUSIONS: Alarm type is an important consideration for certain locations. Photoelectric alarms may be more appropriate for installation nearest to the kitchen despite their increased cost. These findings can help guide consumer choices to increase protection against home fire-related injuries and deaths.

Comprehensive smoke alarm coverage in lower economic status homes: alarm presence, functionality, and placement.

The objectives of this study are to estimate smoke alarm coverage and adherence with national guidelines in low- to mid-value owner-occupied residences, and to identify resident demographic, behavioral, and building characteristics and other fire and burn safety practices associated with smoke alarm utilization. Baseline visits were conducted with 779 households in King County, Washington, for a randomized trial of smoke alarm functionality. Presence, functionality, features, and location of pre-existing smoke alarms were ascertained by staff observation and testing. Household and building descriptors were collected using questionnaires. Households were classified by presence of smoke alarms, functional alarms, and functional and properly mounted alarms placed in hallways and on each floor but not in recommended avoidance locations. Smoke alarms were present in 89%, and functional units in 78%, of households. Only 6-38% met all assessed functionality and placement recommendations. Homes frequently lacked alarms in any bedrooms or on each floor. Building age, but not renovation status, was associated with all dimensions of smoke alarm coverage; post-1980 constructions were 1.7 times more likely to comply with placement recommendations than were pre-1941 homes (95% CI: 1.1-2.6). Respondent education and race/ethnicity, children <5 years, residency duration, number of floors, wood stoves and fireplaces, number of smoke alarms, recency of smoke alarm testing, carbon monoxide monitors, and fire ladders displayed varying relationships with alarm presence, functionality, and placement. Strategies for maintaining smoke alarms in functional condition and improving compliance with placement recommendations are necessary to achieve universal coverage, and will benefit the majority of households.

Empiric management of cyanide toxicity associated with smoke inhalation.

Enclosed-space smoke inhalation is the fifth most common cause of all unintentional injury deaths in the United States. Increasingly, cyanide has been recognized as a significant toxicant in many cases of smoke inhalation. However, it cannot be emergently verified. Failure to recognize the possibility of cyanide toxicity may result in inadequate treatment. Findings suggestive cyanide toxicity include: (1) a history of an enclosed-space fire scene in which smoke inhalation was likely; (2) the presence of oropharyngeal soot or carbonaceous expectorations; (3) any alteration of the level of consciousness, and particularly, otherwise inexplicable hypotension (systolic blood pressure ≤90 mmHg in adults). Prehospital studies have demonstrated the feasibility and safety of empiric treatment with hydroxocobalamin for patients with suspected smoke inhalation cyanide toxicity. Although United States Food and Drug Administration (FDA)-approved since 2006, the lack of efficacy data has stymied the routine use of this potentially lifesaving antidote. Based on a literature review and on-site observation of the Paris Fire Brigade, emergency management protocols to guide empiric and early hydroxocobalamin administration in smoke inhalation victims with high-risk presentations are proposed.

Do Sleeping Children Respond Better to a Smoke Alarm That Uses Their Mother's Voice?

OBJECTIVE: Being asleep at the time of a residential fire increases fire-related fatality risk. This study tested whether children awaken from slow wave sleep and perform an escape procedure better to a voice smoke alarm that uses their mother's voice compared with a female stranger's voice or a low-frequency tone alarm. METHODS: Using a randomized, nonblinded, repeated measures design, 176 children 5 to 12 years old were exposed during stage 4 slow wave sleep to 4 smoke alarm signals: 1) the voice of the child's mother, 2) the voice of a female stranger, 3) low-frequency 500 Hz square wave tone, and 4) conventional residential high-frequency tone. The alarms were assessed regarding their ability to awaken the children and prompt their performance of an escape procedure. RESULTS: Among the 176 subjects, 78.4%, 83.0%, 88.1%, and 49.4% awakened and 78.4%, 81.3%, 85.8%, and 48.3% successfully performed the escape procedure within 5 minutes of alarm onset in response to the mother's voice, stranger's voice, low-frequency tone, and high-frequency tone alarms, respectively; while the median time-to-escape was 23.0, 24.0, 41.5, and >300 seconds for these 4 alarms, respectively. CONCLUSIONS: The 2 voice alarms and low-frequency tone alarm significantly outperformed the high-frequency tone alarm, with the low-frequency tone alarm and female stranger's voice alarm performing best. Compared with the voice of a female stranger, personalizing the alarm message with the voice of the child's mother did not increase alarm effectiveness. These findings provide important information for development of an effective and practical smoke alarm for children.