ARTICLES

Effects of HEPA Air Cleaners on Unscheduled Asthma Visits and Asthma Symptoms for Children Exposed to Secondhand Tobacco Smoke

AUTHORS: Bruce P. Lanphear, MD, MPH,a,b Richard W. WHAT’S KNOWN ON THIS SUBJECT: Exposure to secondhand Hornung, DrPH,b Jane Khoury, PhD,b Kimberly Yolton, smoke (SHS) is associated with asthma exacerbations in PhD,b Michelle Lierl, MD,b and Amy Kalkbrenner, PhDc children. Anticipatory guidance has failed to reduce SHS in aChild and Family Research Institute, British Columbia Children’s controlled trials. It is not known whether high-efficiency, particle- Hospital and Faculty of Health Sciences, Simon Fraser arresting (HEPA) air cleaners can reduce SHS or improve asthma b University, Vancouver, British Columbia, Canada; Cincinnati symptoms in children. Children’s Environmental Health Center, Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio; and cDepartment of Epidemiology, School of WHAT THIS STUDY ADDS: HEPA air cleaners led to reductions in Public Health, University of North Carolina, Chapel Hill, North unscheduled asthma visits and fine airborne particle levels but Carolina not asthma symptoms or cotinine levels. HEPA air cleaners may KEY WORDS be useful as part of a multifaceted strategy to reduce asthma asthma, children, secondhand smoke, air cleaner, randomized morbidity among children. controlled trial, unscheduled asthma visits, exacerbations ABBREVIATIONS HEPA—high-efficiency, particle-arresting SHS—secondhand smoke This trial has been registered at www.clinicaltrials.gov (identifier NCT00006565). abstract www.pediatrics.org/cgi/doi/10.1542/peds.2009-2312 OBJECTIVE: The goal was to test the effects of high-efficiency, particulate- doi:10.1542/peds.2009-2312 arresting (HEPA) air cleaners on unscheduled asthma visits and symp- Accepted for publication Oct 1, 2010 toms among children with asthma exposed to secondhand smoke. Address correspondence to Bruce P. Lanphear, MD, MPH, 3415 METHODS: We enrolled 225 eligible children who were 6 to 12 years of age, Ash St, Vancouver, British Columbia, Canada V5Z 3E5. E-mail: had physician-diagnosed asthma, and were exposed to Ն5 cigarettes per [email protected] day. We conducted a double-blind, randomized trial. Children were as- PEDIATRICS (ISSN Numbers: Print, 0031-4005; Online, 1098-4275). signed randomly to receive 2 active or inactive HEPA air cleaners. Copyright © 2011 by the American Academy of Pediatrics RESULTS: Of 225 enrolled children, 110 (49%) were assigned to the FINANCIAL DISCLOSURE: The authors have indicated they have intervention group and 115 (51%) to the control group; 215 (95%) no financial relationships relevant to this article to disclose. completed the trial. During the trial, there were 42 fewer unscheduled Funded by the National Institutes of Health (NIH). asthma visits among children in the intervention group (18.5% [95% confidence interval: 1.25%–82.75%]; P ϭ .043), compared with those in the control group, after adjustment for baseline differences. There was a significant difference in the reductions of levels of particles of Ͼ0.3 ␮m according to group assignment; there was a 25% reduction in particle levels in the intervention group, compared with a 5% reduction in the control group (P ϭ .026). There were no significant differences in parent-reported asthma symptoms, exhaled nitric-oxide levels, air nic- otine levels, or cotinine levels according to group assignment. CONCLUSIONS: These results hold promise for using HEPA air cleaners as part of a multifaceted strategy to reduce asthma morbidity, but further research is necessary before they can be recommended rou- tinely for the medical management of asthma. Pediatrics 2011;127:93– 101

PEDIATRICS Volume 127, Number 1, January 2011 93 Downloaded from www.aappublications.org/news by guest on September 24, 2021 Exposure to secondhand smoke (SHS) to reduce environmental triggers blend of cotton and polyester fibers), is associated with wheezing and among children with asthma, but it which also were present in the active asthma exacerbations in children.1–7 was not possible to quantify the spe- air cleaners. At the end of the trial, we Children who are exposed to SHS are cific contribution of the air cleaners offered to install HEPA filters in the air ϳ1.5 times more likely to have because the studies involved multiple cleaners for families assigned to re- physician-diagnosed asthma or wheez- environmental interventions.28,29 We ceive inactive air cleaners during the ing than are unexposed children, speculated that children with asthma trial. which accounts for 130 000 excess who were exposed to SHS would par- The Cincinnati Children’s Hospital Med- cases of asthma among US children.3,7 ticularly benefit by using air cleaners. ical Center institutional review board The mechanism for asthma exacerba- The purpose of this double-blind, ran- approved this study. Parents or legal tions resulting from SHS is not clear, domized trial was to test the efficacy of guardians provided written consent but cigarette smoke is the major HEPA air cleaners in reducing un- before enrollment. source of airborne particles in house- scheduled asthma visits, asthma holds with smokers.8 Indeed, concen- symptoms, and SHS exposure among Study Participants Ͻ children with asthma. trations of airborne particles of 2.5 We screened children and their fami- ␮m are 2 to 3 times higher in house- METHODS lies for eligibility from May 31, 2001, holds with smokers than in house- through March 27, 2003, by using a 8–10 holds without smokers. More than Study Design sampling frame of children who had 20% of US children are exposed to The Cincinnati Asthma Prevention received treatment for asthma at a household SHS.11 Study was a randomized, double-blind clinic, emergency department, or hos- Numerous studies have tested the effi- trial to test the effects of HEPA air pital affiliated with Cincinnati Chil- cacy of anticipatory guidance to re- cleaners, in the homes of 225 SHS- dren’s Hospital Medical Center or duce SHS exposure for children, but exposed children with physician- Group Health Associates. Initially, we the majority failed to show significant diagnosed asthma, on unscheduled mailed letters to families. Potential reductions in children’s SHS exposure asthma visits and symptoms. Families participants were able to decline any by using measurements of cotinine, a assigned to the intervention group re- further involvement or telephone con- metabolite of nicotine, or improve- ceived 2 active HEPA air cleaners (Aus- tact by returning a prepaid postcard ments in asthma symptoms.12–23 This tin Healthmate [Buffalo, NY]), that is, or by telephoning our research coordi- problem might be overcome if there HEPA air cleaners surrounded by a car- nators. If the family did not decline par- was a technology to reduce SHS bon-potassium permanganate-zeolite ticipation within 10 days, then a re- exposure passively, such as high- insert, whereas families in the control search coordinator contacted the efficiency, particulate-arresting (HEPA) group received 2 inactive (placebo) air family to describe the study, to deter- air cleaners. cleaners. For both groups, 1 air mine eligibility, and, if the family was There are limited data on the efficacy cleaner was installed in the main activ- eligible, to invite the members to par- of HEPA air cleaners in reducing ity room and the other was installed in ticipate in the trial. asthma symptoms. More than 10 trials the child’s bedroom at the baseline Children were eligible if they were 6 to have tested the effects of HEPA air home visit. The air cleaners were 12 years of age at enrollment, had cleaners, but the largest involved 45 equipped with monitors to measure physician-diagnosed asthma in the subjects; only 2 studied children exclu- the number of hours they operated. previous 12 months, according to In- sively.24,25 None of those trials tested There were no attempts to reduce to- ternational Classification of Diseases, HEPA air cleaners among SHS-exposed bacco use or other asthma triggers. Ninth Revision, billing codes (from hos- children with asthma, but HEPA air HEPA air cleaners are certified to re- pital records, emergency department cleaners can reduce levels of airborne move Ͼ99% of airborne particles of visit records, or primary care physi- particles and nicotine.26,27 Reisman et Ͼ0.3 ␮m in a 1500-ft2 room. The cian records), experienced Ն1 exacer- al26 reported a 73% reduction in the carbon-potassium permanganate- bation requiring an unscheduled visit level of airborne particles of Ն0.3 ␮m zeolite filter insert was designed to ab- in the past year, were exposed to the with HEPA air cleaners. Bascom et al27 sorb odors and gases. The inactive air smoke of Ն5 cigarettes per day in and reported 50% reductions in levels of cleaners, which were indistinguish- around the house, and lived within a airborne particles and nicotine. Other able from the active HEPA air cleaners, 9-county area surrounding Cincinnati. trials incorporated HEPA air cleaners contained 3 layers of prefilter cloth (a Children were excluded if they were al-

94 LANPHEAR et al Downloaded from www.aappublications.org/news by guest on September 24, 2021 ARTICLES ready using an air cleaner, if their would have a rate of attrition of Ͻ10%. concentrations of indoor particles home lacked electricity, if they had co- Secondary outcome measures in- (particles per cubic foot) at the base- existing medical problems (eg, mental cluded asthma symptoms assessed line and 6- and 12-month visits. We took retardation, congenital heart disease, with the Child Health Asthma Survey measurements of the numbers of air- or cystic fibrosis), or if their family (an instrument shown to be reliable, borne particles of Ͼ0.3 ␮m and Ͼ5 planned to move in the next year. internally consistent, and able to dis- ␮m; each reading was the average of tinguish levels of asthma severity30,31), ten 6-second measurements taken Random Assignment tobacco smoke exposure, indoor air- over 1 minute in 3 different locations in Children were assigned randomly to borne particle levels, and exhaled each housing unit. The data used in the receive active HEPA air cleaners or in- nitric-oxide levels. analysis are the mean of 3 readings active air cleaners. Allocation conceal- Air nicotine levels, which provide an from the main activity room, the child’s ment was performed by using opaque objective measure of ambient tobacco bedroom, and the kitchen, taken at the envelopes, which were opened by a re- smoke exposure, were measured in beginning of each home visit. search assistant immediately before each subject’s home by using nicotine We assessed nitric-oxide levels in ex- the baseline home visit was con- dosimeters.32–34 For standardization, haled air at the baseline and 6- and ducted. With the exception of the serial the dosimeters were housed in a metal 12-month visits. Exhaled air was col- numbers, the active and inactive HEPA compartment on the air cleaner that lected in Mylar balloons from each air cleaners were indistinguishable. was located in the main activity room. participant by using a validated offline All of the investigators, research staff Dosimeters were placed at the base- technique to assess the effect of HEPA members, and participants were line and 6-month visits and were re- air cleaners on airway inflamma- masked to group assignment until the trieved at the 6- and 12-month visits, tion.38,39 A model 280i nitric-oxide ana- end of the trial, except for the biostatisti- respectively. The dosimeters, which lyzer (Sievers Instruments, Boulder, cian (Dr Hornung), who was responsible have a limit of detection of 0.01 ␮g per CO) was used for nitric-oxide analysis. for random permutation of the air clean- filter, were analyzed by using a stan- As described previously, exhaled ers by using serial numbers. dardized protocol.32–34 nitric-oxide concentrations were im- Outcome Measures To test the efficacy of the HEPA air puted when the exhaled nitric-oxide analysis did not occur within 24 hours We conducted extensive surveys at cleaners in reducing children’s SHS ex- after collection.40 baseline to characterize the children, posure, we measured cotinine levels in their families, and the home environ- children’s serum and hair at baseline Serum samples were obtained at the 35 ment. Research assistants surveyed and at 6 and 12 months. Serum sam- baseline visit by a trained pediatric the children’s parent or guardian at ples were analyzed at the National Cen- phlebotomist, for determination of baseline and at 3-month intervals ter for Environmental Health, Centers allergen-specific immunoglobulin E by about unscheduled asthma visits, for Disease Control and Prevention (At- using the ImmunoCap test (Pharmacia asthma symptoms, therapy, and to- lanta, GA), by using high-performance Diagnostics, Portage, MI). Children bacco exposure. Our primary outcome liquid chromatography linked to atmo- with class I or higher immunoglobulin Ն measure was asthma exacerbation, spheric pressure chemical ionization/ E levels ( 0.35 kU/L) for dust mite, defined as any unscheduled visit to a tandem mass spectrometry.36 The de- dog, cat, or cockroach allergen were health care provider (clinic visit, emer- tection limit for cotinine in serum was considered to have atopy. gency visit, or hospitalization). We se- 0.05 ng/mL. We collected 20 strands of lected unscheduled asthma visits as hair from the occipital region of the Statistical Analyses our primary outcome measure a priori scalp. The hair samples were analyzed We calculated descriptive statistics because it was the most-objective for cotinine at the Hospital for Sick according to group assignment. For measure of asthma exacerbation. We Children (Toronto, Ontario, Canada), by continuous variables, we calculated estimated that, to detect a 20% reduc- using a radioimmunoassay.37 The de- means, SDs, and ranges. For categori- tion in unscheduled visits attributable tection limit for cotinine in hair was cal variables, we calculated frequen- to asthma exacerbations with Ն80% 0.005 ng/mg.37 cies and proportions. All analyses power, we would require a sample size To test the effect of the HEPA air clean- were performed according to the in- of 110 children per group, or a total of ers on airborne particles, we used a tention to treat. For continuous vari- 220 children (␣ ϭ .05, 2-tailed test). GT-321 particle counter (Met One In- ables, we used multivariate regression This calculation assumed that we struments, Grant Pass, OR) to measure analyses for either the untransformed

PEDIATRICS Volume 127, Number 1, January 2011 95 Downloaded from www.aappublications.org/news by guest on September 24, 2021 FIGURE 1 Enrollment, random assignment, and retention of Cincinnati Asthma Prevention study participants. or logarithmically transformed out- of Diseases, Ninth Revision, billing dren were exposed to a geometric come, as appropriate. For repeated- codes, and resided in a 9-county area mean of 13 cigarettes per day. Num- measures analyses over the 12 months surrounding Cincinnati, we screened bers of unscheduled asthma visits and of the study, we used mixed-effects lin- 1694 (76%) for eligibility between May airborne particle levels were signifi- ear models with an autoregressive co- 31, 2001, and March 27, 2003. Of these cantly greater in the control group. variance structure. The interaction of children, 353 (21%) were eligible to Some other measures of asthma se- group assignment and time was tested participate (Fig 1). Of the 353 eligible verity tended to be greater in the con- as the primary hypothesis of an inter- children and their families, 225 (64%) trol group, but these differences were vention effect. When the outcome was agreed to participate in the trial. not statistically significant (Tables 1 a rate or count (eg, unscheduled There were no significant differ- and 2). Of the 225 children enrolled in asthma visits), the generalized esti- ences in children’s age, gender, the trial, 215 (95%) completed the mating equation version of Poisson re- asthma severity, or race, parents’ study (Fig 1). gression was used for repeated mea- education, marital status, household In unadjusted analyses, there were sures, in a manner similar to the income, or health insurance, or num- fewer unscheduled asthma visits at mixed-effects linear model. In second- ber of cigarettes smoked in or ary a priori analyses, we tested the ef- follow-up assessment in the interven- around the house per day for fami- ϭ ficacy of the HEPA air cleaners for fam- tion group (189 vs 274 visits; P .046). lies that chose to participate versus ilies who used either HEPA air cleaner This difference persisted after adjust- those that chose not to participate. for Ͼ6130 hours (ie, Ն70% of the ment for baseline differences in the entire trial). Of the 225 families that agreed to par- multivariate analyses. With adjust- ticipate, 110 (49%) were assigned ran- ment for baseline differences, there RESULTS domly to the intervention group and was a significant difference in the rate Of the 2240 children in the sampling 115 (51%) to the control group. At of decrease in the number of unsched- frame who were 6 to 12 years of age, baseline, the mean age of the children uled asthma visits among children in had physician-diagnosed asthma ac- was 8.6 years (range: 5.3–11.7 years); the intervention group, compared with cording to International Classification 62% of the children were male. Chil- the control group (Fig 2). The adjusted

96 LANPHEAR et al Downloaded from www.aappublications.org/news by guest on September 24, 2021 ARTICLES

TABLE 1 Baseline Characteristics of Study Population According to Group Assignment 0.8 Characteristics Intervention Control Group P Group (N ϭ 115) (N ϭ 110) 0.6 Age, mean Ϯ SD, y 8.8 Ϯ 1.8 8.4 Ϯ 1.8 .160 Male, n (%) 74 (67) 65 (57) .097 Race, n (%) .565 Black 65 (59) 60 (52) — 0.4 White 43 (39) 52 (45) — Other 2 (2) 3 (3) — Annual household income, mean Ϯ SD, $ 30 524 Ϯ 24 416 29 595 Ϯ 21 649 .767 0.2 No. of unscheduled asthma visits in previous 0.6 Ϯ 1.0 1.0 Ϯ 1.4 .013

3 mo, mean Ϯ SD Mean No. of unscheduled asthma visits Measures of asthma severity, n (%) Allergy severity (moderate to very severe) 47 (43) 55 (48) .443 0.0 036912 Shortness of breath (moderate to very severe) 46 (42) 61 (53) .104 Time, mo Tightness in chest (moderate to very severe) 29 (27) 37 (33) .317 FIGURE 2 Wheeze (moderate to very severe) 44 (40) 46 (40) .955 Mean numbers of unscheduled asthma visits in Difficulty sleeping (moderate to very severe) 42 (38) 53 (46) .208 the previous 3 months, reported at quarterly Steroid therapy in previous 3 mo 30 (27) 37 (34) .305 intervals during the trial, according to group Long-acting steroid therapy 58 (53) 60 (52) .877 assignment, with adjustment for differences in the numbers of unscheduled asthma visits at Duration of asthma, mean Ϯ SD, d 9.8 Ϯ 18.7 10.2 Ϯ 11.7 .841 baseline. The solid line and closed circles indi- Serum immunoglobulin E levels of Ն0.35 kU/L for 74 (67) 70 (61) .310 cate the intervention group; dashed line and common allergens, n (%) open circles, control group. Exhaled nitric-oxide level, mean Ϯ SD, ppb 14.7 Ϯ 10.0 16.3 Ϯ 12.3 .302

TABLE 2 Baseline Exposure to Environmental Tobacco Smoke and Indoor Airborne Particles There was a significant difference in According to Group Assignment the reductions in the numbers of air- Characteristics Intervention Group Control Group P borne particles of Ͼ0.3 ␮m according (N ϭ 110) (N ϭ 115) to group assignment (P ϭ .026) (Table Tobacco exposure 4). The absolute mean reduction in lev- No. of cigarettes smoked around house 12.9 Ϯ 1.8 13.3 Ϯ 2.2 .716 Ͼ ␮ per d, mean Ϯ SD els of airborne particles of 0.3 m Serum cotinine level, mean Ϯ SD, ng/mL 1.18 Ϯ 3.9 1.23 Ϯ 3.3 .622 during the trial was 1.1 ϫ 106 particles Hair cotinine level, mean Ϯ SD, ng/mg 0.14 Ϯ 3.8 0.14 Ϯ 3.5 .970 per ft3 for the intervention group, Ϯ 6 3 No. of airborne particles, mean SD, 10 /ft which was equivalent to a 25% reduc- Particles of Ͼ0.3 ␮m 4.0 Ϯ 2.56 4.7 Ϯ 2.58 .003 Particles of Ͼ5 ␮m 0.003 Ϯ 2.31 0.004 Ϯ 2.14 .154 tion in airborne particle levels. In con- trast, there was a reduction of only 0.3 ϫ 106 particles per ft3 (5%) for the mean number of unscheduled visits In a secondary analysis, developed a control group. There was no signifi- for the intervention group decreased priori, we examined the effect of HEPA cant difference in levels of airborne by 8.9% per month, compared with a air cleaners among 141 (68%) of 207 particles of Ͼ5 ␮m according to group decrease of 0.9% per month in the con- families with functioning monitors assignment (Table 4). trol group. With adjustment for base- who used 1 or both air cleaners Ͼ70% line differences, there were 185 un- of the time. With adjustment for base- There were no significant differences scheduled asthma visits among line differences in unscheduled between groups with respect to sever- children in the intervention group, asthma visits, the rate of reduction in ity of asthma symptoms, medication compared with 227 unscheduled the number of unscheduled asthma use, exhaled nitric-oxide levels, air nic- asthma visits among children in the visits over time was significantly otine levels, serum cotinine levels, or control group, a reduction of 42 visits greater in the intervention group, com- hair cotinine levels during the trial (Ta- (95% confidence interval: 1.25–82.75 pared with the control group (P ϭ ble 3). There were no significant group- visits; P ϭ .043). This is equivalent to a .006). The number of unscheduled season (P ϭ .328) or group-allergy se- reduction of 18.5% (95% confidence in- asthma visits for the intervention verity (P ϭ .583) interactions for terval: 1%–36%) in the number of un- group decreased by 12.7% per month, unscheduled asthma visits. scheduled asthma visits during the compared with an increase of 0.7% per To validate parents’ reports of un- study (Table 3). month in the control group. scheduled visits, we examined the rate

PEDIATRICS Volume 127, Number 1, January 2011 97 Downloaded from www.aappublications.org/news by guest on September 24, 2021 TABLE 3 Numbers of Unscheduled Asthma Visits, Asthma Symptoms, Reported Exposure to visits) were in agreement with billing Tobacco Smoke, and Exhaled Nitric-Oxide Levels According to Group Assignment records for each 3-month interval. Characteristics 3 mo 6 mo 9 mo 12 mo P No. of unscheduled asthma visits in previous 3 mo, mean .043a DISCUSSION Intervention group (n ϭ 110) 0.7 0.5 0.4 0.3 Control group (n ϭ 115) 0.6 0.5 0.9 0.6 We found, in a randomized, double- Moderate/severe allergy in previous 3 mo, % .618 blind trial, that HEPA air cleaners led to Intervention group (n ϭ 110) 35 32 40 33 Control group (n ϭ 115) 38 40 34 34 an 18.5% reduction in unscheduled In previous 2 wk, how much of time has Ͻchild’s nameϾ asthma visits. The differences in un- had scheduled asthma visits were appar- Shortness of breath (some, most, or all of time), % .415 Intervention group (n ϭ 110) 34 28 29 19 ent only at 9 and 12 months. We also Control group (n ϭ 115) 36 27 24 28 found a significant difference in the re- Tightness in chest (some, most, or all of time), % .612 duction of levels of airborne particles Intervention group (n ϭ 110) 22 16 18 14 Ͼ ␮ Control group (n ϭ 115) 22 10 16 17 of 0.3 m in the intervention group, Wheeze (some, most, or all of time), % .168 compared with the control group. In Intervention group (n ϭ 110) 32 15 22 13 contrast, there were not significant re- ϭ Control group (n 115) 25 20 15 19 ductions in levels of the gaseous phase Difficulty sleeping (some, most, or all of time), % .299 Intervention group (n ϭ 110) 26 21 27 21 of SHS exposure, asthma symptoms, or Control group (n ϭ 115) 27 18 16 18 exhaled nitric oxide. These data sug- Prescription for steroid therapy in previous 3 mo, % .811 gested that HEPA air cleaners reduced Intervention group (n ϭ 110) 19 13 16 19 Control group (n ϭ 115) 27 25 18 27 unscheduled asthma visits for chil- Prescription for long-acting steroid therapy in previous .135 dren by reducing exposure to airborne 3 mo, % particles of Ͼ0.3 ␮m but without a Intervention group (n ϭ 110) 36 43 42 39 Control group (n ϭ 115) 46 39 30 37 corresponding reduction in the gas- No. of episodes of asthma, mean .294 eous phase of tobacco smoke. Intervention group (n ϭ 110) 8.9 4.3 6.5 4.5 Control group (n ϭ 115) 9.3 6.0 6.3 6.8 Although these results are somewhat Exhaled nitric-oxide level, mean, ppb .313 paradoxical, our results are consistent Intervention group (n ϭ 110) — 16.4 — 16.1 with other controlled trials of environ- Control group (n ϭ 115) — 15.0 — 16.8 No. of cigarettes smoked around house per d, mean .977 mental interventions. In a multifaceted Intervention group (n ϭ 110) 7.5 11.2 7.5 9.5 trial to reduce indoor pollutants that Control group (n ϭ 115) 7.5 10.6 7.1 9.5 included portable HEPA air cleaners, a Test of group difference in trends over time (group-time interaction), adjusted for differences in the number of baseline visits. Morgan et al28 reported a 13.6% reduc- tion in the number of unscheduled vis- TABLE 4 Exposures to Tobacco and Indoor Particles, According to Group Assignment, During Study its attributable to asthma and a signif- Characteristic Baseline 6 mo 12 mo P icant reduction in asthma symptoms. Serum cotinine level, mean, ng/mL .738 In a trial of multiple environmental in- Intervention group (n ϭ 110) 1.1 1.1 1.1 terventions that included HEPA air Control group (n ϭ 115) 1.2 1.1 1.0 Hair cotinine level, mean, ng/mg .984 cleaners, Eggleston et al29 reported a Intervention group (n ϭ 110) 0.1 0.12 0.15 significant improvement in asthma Control group (n ϭ 115) 0.1 0.11 0.15 Air nicotine level, ␮g .191 symptoms but no difference in un- Intervention group (n ϭ 110) — 3.1 2.5 scheduled asthma visits according to Control group (n ϭ 115) — 2.5 2.7 No. of particles of Ͼ0.3 ␮m, mean Ϯ SD, 106/ft3 .026a group assignment. In a trial to reduce Intervention group (n ϭ 110) 4.0 2.5 3.0 exposures to indoor asthma triggers Control group (n ϭ 115) 4.7 4.6 4.4 No. of particles of Ͼ5 ␮m, mean Ϯ SD, 106/ft3 .219a among inner-city children that did not Intervention group (n ϭ 110) 0.0033 0.0029 0.0027 include portable air cleaners, Krieger Control group (n ϭ 115) 0.0037 0.0028 0.0024 et al41 reported a 15% reduction in un- a Test of differences in group means, including baseline particle levels. scheduled asthma visits but no signifi- cant improvement in asthma symp- of agreement of parent-reported un- Children’s Hospital Medical Center. We toms. It is not clear whether the scheduled asthma visits by using med- found that 87% of parent-reported un- differences across these studies are ical billing records from the Cincinnati scheduled asthma visits (714 of 824 attributable to the type or intensity of

98 LANPHEAR et al Downloaded from www.aappublications.org/news by guest on September 24, 2021 ARTICLES the environmental intervention, sam- as cotinine levels, reported, and from HEPA air cleaners in the main activity ple size, or eligibility criteria. Collec- another study a significant reduction rooms, might not have provided rep- tively, however, these trials provide in the number of unscheduled asthma resentative measurements of house- evidence that environmental interven- visits was reported.12,13 Collectively, hold exposure. Finally, by focusing on tions can reduce asthma morbidity in these trials raise serious questions older children, who are less vulnera- children.42 about whether it is prudent to continue ble to SHS exposure,7,43,44 we might Results of studies that have exam- to rely on anticipatory guidance to re- have decreased our chances of showing ined the contribution of SHS expo- duce children’s exposure to tobacco an effect of HEPA air cleaners. smoke. Our failure to show a reduction sure to asthma exacerbations in chil- CONCLUSIONS dren Ͼ3 years of age have been in the gaseous phase of children’s ex- posure to SHS by using a passive envi- inconsistent. Several studies found Our ultimate goal should be to elimi- ronmental intervention provides addi- that SHS was associated with asthma nate tobacco use and SHS exposure tional support for regulations to ban exacerbations or bronchial hyperac- for children. Despite efforts to re- smoking in public places and residen- Ͼ tivity in older children, whereas oth- duce exposure, 20% of US children tial settings to reduce children’s expo- are exposed to SHS in their homes.11 ers did not.3,6,7,43,44 The vast majority sure to tobacco smoke. Moreover, air quality in housing of- of studies relied on parents’ reports ten is inadequate.10 Therefore, it is of smoking behavior to quantify the There are some limitations of this critical to identify ways to reduce ex- risk of asthma, wheezing, or dimin- study. First, our primary outcome posure to SHS and other pollutants, ished pulmonary functions associ- measure, that is, numbers of un- especially for children with asthma. ated with SHS exposure; fewer stud- scheduled asthma visits, and air- We found that HEPA air cleaners led ies used objective biomarkers such borne particle levels were not to significant reductions in numbers as cotinine levels.7,43,44 Although we equally distributed in our 2 treat- of unscheduled asthma visits and found a significant reduction in the ment arms at baseline; although the levels of fine airborne pollutants but number of unscheduled asthma vis- decreases in the number of unsched- uled asthma visits and levels of air- not in parent-reported asthma symp- its among children, there was not a borne particles of Ͼ0.3 ␮m re- toms, cotinine levels, or exhaled corresponding reduction in the gas- mained statistically significant after nitric-oxide levels. These results hold eous phase of tobacco smoke, as as- adjustment for baseline differences, promise for using HEPA air cleaners sessed with objective measures of this suggests that the 2 groups were as part of a multifaceted strategy to air nicotine levels and biomarkers of not equivalent. Second, we examined reduce asthma morbidity, but they internal doses. In contrast, there many relevant end points and our also emphasize the importance of was a reduction in the levels of fine primary result, that the air cleaners finding ways to reduce the sources of indoor particles, the predominant led to a significant reduction in the exposure further. size generated by tobacco smoke. number of unscheduled asthma vis- Therefore, this study provides some its, might have been spurious. This is ACKNOWLEDGMENTS evidence that airborne particles unlikely, however, because we ob- This work was funded by National Insti- from SHS or other pollutants repre- served a larger effect among the tutes of Health grant RO1-65731. Austin sent a risk factor for asthma exacer- families who used the air cleaners Air provided the HEPA air cleaners at a bations in children. consistently. Third, use of a different reduced cost, but the company was not More than 10 trials have tested the HEPA air cleaner might have led to involved in study design, data interpre- efficacy of anticipatory guidance re- different results. Fourth, we used tation, or manuscript preparation. garding children’s exposure to to- only 2 HEPA air cleaners in each We acknowledge the contributions of bacco smoke, by using cotinine as an housing unit. A portable HEPA air Katharine Hammond, the Cincinnati objective biomarker of exposure.12–23 cleaner is certified to clean 1 Asthma Prevention Study research staff Only from 1 of those studies was a sus- average-sized room and not an en- members, and the pediatricians at Cin- tained reduction in exposure to envi- tire house. Fifth, the air nicotine do- cinnati Children’s Hospital Medical Cen- ronmental tobacco smoke, measured simeters, which were placed on the ter and Group Health Associates.

PEDIATRICS Volume 127, Number 1, January 2011 99 Downloaded from www.aappublications.org/news by guest on September 24, 2021 REFERENCES

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MISTAKES IN THE HOSPITAL: Patients are taken to the hospital to get better. Unfortunately, hospitalization carries with it a significant risk for adverse events. As reported on NewYorkTimes.com (November 16, 2010:1–3), one of every seven hospitalized Medicare beneficiaries is harmed as a result of the medical care received. The report on patient safety from the Inspector General for the Department of Health and Human Services is based on an exhaustive review of a representative sample of 780 patient files. The report estimates that in October 2008 alone, approximately 134,000 hospitalized Medicare beneficia- ries experienced at least one adverse event. Events ranged from mild and tem- porary to severe and permanent including death. Almost 44% of these events were likely preventable. Medication errors leading to such problems as exces- sive bleeding were the most frequent adverse event. Poor patient management, e.g. leading to fluid overload was also common. Hospital acquired infections continue to be a major issue. Extremely infrequent are problems that should never happen under any condition such as performing surgery on the wrong patient. While physicians and hospitals have designed systems to help prevent errors, errors continue to happen at a distressing rate. The report recommends not only to broaden the definitions of error and harm in the hospital but to give hospitals financial incentives to reduce errors. While pediatricians infrequently take care of Medicare patients, the report emphasizes that we all need to be mindful of a cardinal rule in medicine: first, do no harm. Noted by WVR, MD

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