How to help clinicians retrieve clinically relevant and scientifically sound reports of studies, quickly and efficiently, using validated search strategies.

Background

The Challenge: How to find useful information quickly?
Biomedical information repositories such as Ovid MEDLINE and Embase on Ovid, contain tens of millions of database records on past and currently available medical literature. Updated on a regular basis, they are large, diverse, highly structured and relentlessly dynamic general purpose resources. This can present challenges to health care professionals in clinical settings, for whom (a). only a sub-set of the database is relevant to them, and (b). they need to be able to quickly locate references that they can be sure are both clinically relevant and scientifically sound.

The Solution: Tested and trusted search filters
An important category of tried, tested and trusted database search filters are validated search filters. These are search strategies made available by subject matter and information experts who have constructed and developed them using a reference set of data as a ‘gold standard’. The resulting search filters are then tested against a test set of references in order to assess their effectiveness in terms of targeted and reliable information retrieval. Where they consistently exceed a certain threshold they are deemed ‘validated’. Although such search filters, as is here the case, may only be comprised of 4-6 search expression lines, the fact of their validation accords them a preferred status in terms of being an information retrieval option. In short, validated search filters are high quality, reliable ‘knowledge assists’ that help both clinicians and those that advise them on information retrieval matters, e.g. librarians and information specialists, to find useful information quickly.

The Source: Clinical Queries from McMaster University in Canada
As used here by Focused Searches, the phrase ‘clinical queries’ refers to database search filters that have been developed by the Health Information Research Unit (HIRU), based at McMaster University in Canada. Made available as part of their Hedges Project, the clinical query validated search filters cover dedicated ‘purpose categories’ surrounding human health disorders. The purpose categories are causation (etiology), course (prognosis), diagnosis, treatment and therapy, clinical predictions, the economics around human health disorders, studies of quality improvement of health services as well as continuing education of health care professionals. For fuller information on clinical queries, their origins as well as a list of accompanying references, please see  https://hiruweb.mcmaster.ca/hkr/hedges/ .

How to make best use of clinical queries?
This Focused Search presents the clinical query for the HIRU ‘purpose category’ Reviews, in three versions. The first version (see #1 in the table below), when used in combination with a human health disorder, has been tuned for maximized sensitivity. This is a broad search that will seek to return the highest proportion of relevant results pertaining to treatments and therapies related to the specified human health disorder. It may also include some less relevant results. By contrast its counterpart (see #2 in the table below) which is tuned for maximized specificity, constitutes a narrow search. It will seek to return the highest possible proportion of least relevant results. Being then such a targeted search, designed to include only the most relevant results, it may in doing so miss some of these otherwise wished for references. A third option (see #3 in the table below) is a search that has been tuned to seek a middle way between the broad and narrow search options, that is, to obtain the best balance between sensitivity and specificity. 

Adapted from https://hiruweb.mcmaster.ca/hkr/hedges/medline/

Are these search filters still up to date?
Yes, the clinical query validated search filters are up to date. For further information, please refer to the publications listed in Re: Search Filter - Currency: in the References section below.

Why does the Focus Search display as a list of search lines?
The format of the rendered Focused Search for this clinical query is in two parts. The first part is a single line which contains all the clinical query’s relevant terms and expressions. The second part splits the constituent terms and expressions into their component sub-parts and then lists these line by line. At the bottom of the list of component sub-parts the OR operator is then used to obtain an overall result for all the terms and expressions in combination. This result should always be the same as the very first line. The aim of unpacking the clinical query line by line in this way is to ensure the purpose behind each line is understood as is the Ovid syntax used in the line’s construction.

Ovid Syntax Check

• An .mp or ‘multi-purpose’ search, searches across a set of default fields for the database.
• ‘pt’ stands for ‘publication type’, a specifically indexed field in Ovid MEDLINE.
• ‘tw’ stands for ‘text word’, a field in Ovid MEDLINE covering both title (TI) and abstract (AB).
• The expression ‘di.xs’ indicates a search on the MeSH subheading ‘diagnosis’, but as an exploded floating subheading (.xs), i.e. not bound to a specific MeSH term.
• The character ‘:’ is a wildcard denoting truncation. Ovid now more usually uses ‘$’ or ‘*’.
• Search lines can be connected one after the other using the OR operator. Alternatively the search line can be grouped together using the expression ‘or/2-4’ where ‘or’ refers to the OR operator and  the numbers 2-4 refer to the search lines #2, #3 and #4.

Strategy

search:.tw. or meta analysis.mp,pt. or review.pt. or di.xs. or associated.tw. [CQ - Reviews - Maximizes sensitivity]     

search:.tw.

meta analysis.mp,pt.

review.pt.

di.xs. [Searches for 'diagnosis' as an exploded floating subheading (xs)]

associated.tw.

2 or 3 or 4 or 5 or 6 [CQ - Reviews - Maximizes sensitivity]

How to locate specific information on mpox quickly on Ovid MEDLINE.

Background

On 13th August 2024, the African Centres for Disease Control and Prevention (African CDC) issued a public health warning, highlighting the spread of a particular strain of the mpox virus (formerly called the monkeypox virus). (1) The next day, the Director-General of the World Health Organisation (WHO) declared the mpox (monkeypox) outbreak to be a public health emergency of international concern. (2)

Wary of the informational challenges presented only just recently by the onset and impact of the covid 19 pandemic, researchers, health care professionals and policy decision makers all have a pressing need to acquire up to date information on mpox. Be it the virus, the disease or the vaccine or vaccines.

Nomenclature Changes
Locating information relating to mpox has its own unique challenges as the description of the virus and disease has undergone a nomenclature change. On 28th November 2022, the World Health Organisation (WHO) recommended a new name for monkeypox disease, namely ‘mpox’. (3) The recommended change was in keeping with the 2015 WHO publication on best practices in naming diseases.  

“According to these best practices, new disease names should be given with the aim to minimize unnecessary negative impact of names on trade, travel, tourism or animal welfare, and avoid causing offence to any cultural, social, national, regional, professional or ethnic groups.”(3)

However, the name of the virus would remain unchanged – for the time being – to reflect its use in scientific literature. And in doing so, to continue to make relevant documents discoverable and retrievable. Biomedical databases, reflecting scientific publications and their terminological use over decades, have also used the term ‘monkeypox’ in their controlled vocabularies. For database searchers, be they novices or experienced searchers, this semantic transition from old to new, has consequences for database search query design.

Search Blocks
This Focused Search presents three search blocks that will help you quickly locate scientific literature on mpox, and that on the virus, the disease and vaccines, respectively. For ease of initial viewing the three search blocks are listed as a single search history which can be viewed via the Actions / Display option. The same search can be run directly in Ovid by clicking on Actions / Launch.

Search Design
Although listed in the Focused Search as a sequence of three searches, the search blocks were individually designed, constructed and tested. Their construction followed the conventional concept search approach of a database thesaurus search followed by a free term search, followed by the combination of the thesaurus and free term search using the Boolean operator, OR.

In all three cases, the thesaurus term’s Scope Note was used as the initial source of free terms. This was done in anticipation of a degree of similar coverage between the thesaurus term and its kindred free terms. However, where the Scope Note omitted terms or listed terms that, when tested were not found in the scientific literature, the free term search expression was amended accordingly. The details for each of the three search blocks are given in the table below.

The search blocks were peer reviewed by members of the Ovid Training Team

Search Assistance
The purpose of this Focused Search is to help kick-start your searches related to mpox, the virus, the disease and the vaccine(s). And this, for your own purposes as well as to help you assist those you advise and teach. By saving these blocks (with your own amendments and changes) in My Workspace you could combine them with Clinical Queries, for example. Or with respect to the vaccine, with the EMA’s search filter on adverse events. If you would like further assistance on or with this Focused Search, as well as on any aspects related to it, please click on Actions / Ovid Coaching and an Ovid Trainer will contact you. Alternatively, please send an e-mail to us at [email protected] .

Strategy

Monkeypox virus/

(mpxv or monkeypox virus$ or monkey pox virus$ or mpox virus$).mp.

1 or 2  [VIRUS SEARCH: Thesaurus and Free Terms]

"Mpox (monkeypox)"/  

(monkeypox or monkey pox or mpox).mp.

4 or 5  [DISEASE SEARCH: Thesaurus and Free Terms]

Smallpox Vaccine/

(mpxv vaccine$ or monkeypox vaccine$ or monkey pox vaccine$ or mpox vaccine$).mp.

7 or 8  [VACCINE SEARCH: Thesaurus and Free Terms]   

How to incorporate an adverse events search filter from an external, third-party source into your own Ovid search libraries and documents (Part 1).

Background

One of the main drivers behind the OvidGO! / Focused Searches project is to make searches, and especially search filters, discoverable, actionable and useable. Search filters, searches designed to achieve a specific outcome, are particularly challenging. On the one hand they are spread across a large variety of publication vehicles, e.g. journal articles, systematic reviews, websites etc.. A consequence being that many of them are “locked” in analogue formats, most notably print. On the other hand, the role and value of search strategies, filters or otherwise, as the informational foundation of systematic reviews is understated. And as a result, problematic.

An analysis of critically assessed systematic reviews using the KSR Evidence database (also available on Ovid), demonstrates – dramatically – that a large number of currently available systematic reviews have to be marked as having a high risk of bias because they have not at all, or only partially, reported on the search strategies employed for their construction. Ovid’s search strategy construction and sharing functionality, used purposefully and systematically, can help remedy this situation. 

Taking as its reference the Adverse Events (AE) filter published by the European Medicines Agency (EMA), this Focused Search provides an example of what is meant by making search filters, discoverable, actionable and useable.

As part of its pharmacovigilance obligations and activities the EMA is mandated to keep a watching brief over some 300 substance groups and 100 herbal substance groups. Specifically, to monitor medical literature and enter relevant information into the EudraVigilance database. This the EMA does by running search strategies on ‘MEDLINE’ (i.e. via PubMed) that combine (a). a comprehensive list of terms describing the target drug or herbal substances, together with (b). an extensive list of terms and phrases that refer to adverse events in a variety of ways. The list of substances and the AE filter used is available from the EMA and is published and updated regularly. A link to the published document is given below.

The current version of the AE filter, displayed below, can be found on page 13.

AND (Drug-Related Side Effects and Adverse Reactions [MeSH Terms] OR adverse drug reaction[Title/Abstract] OR "adverse effects”[Subheading] OR adverse[Title/Abstract] OR side effects[Title/Abstract] OR side effect[Title/Abstract] OR drug overdose[MeSH Terms] OR drug overdose[Title/Abstract] OR drug overdose*[Title/Abstract] OR drug misuse[MeSH Terms] OR drug misuse[Title/Abstract] OR misus*[Title/Abstract] OR "Substance-Related Disorders"[MeSH Terms] OR drug abuse[Title/Abstract] OR substance abuse[Title/Abstract] OR abus*[Title/Abstract] OR pregnancy[MeSH Terms] OR pregnancy[Title/Abstract] OR pregnan*[Title/Abstract] OR Pregnancy Complications[MeSH Terms] OR "Lactation"[MeSH Terms] OR "Breast Feeding"[MeSH Terms] OR ("milk, human"[MeSH Terms] AND "Bodily Secretions"[MeSH Terms]) OR "Fertility"[MeSH Terms] OR "Reproduction"[MeSH Terms] OR "Fetus"[MeSH Terms] OR "Embryonic Structures"[MeSH Terms] OR "Teratogens"[MeSH:NoExp] OR "Teratogenesis"[MeSH:NoExp] OR terato*[Title/Abstract] OR drug efficacy[Title/Abstract] OR "Substance Withdrawal Syndrome"[MeSH Terms] OR "Medication Errors"[MeSH Terms] OR "Death"[MeSH Terms] OR death*[Title/Abstract] OR "Fatal Outcome"[MeSH:NoExp] OR fatal*[Title/Abstract] OR "Drug Interactions"[MeSH Terms] OR Drug Interaction*[Title/Abstract] OR "Carcinogens"[MeSH:NoExp] OR carcinogen*[Title/Abstract] OR "Mutagens"[MeSH:NoExp] OR "Mutagenesis"[MeSH:NoExp] OR mutagen*[Title/Abstract] OR "Off-Label Use"[MeSH Terms] OR "Occupational Exposure"[MeSH Terms] OR "toxicity”[Subheading] OR toxic*[Title/Abstract] OR pharmacotox*[Title/Abstract] OR "Neurotoxicity Syndromes"[MeSH:NoExp] OR Neurotox*[Title/Abstract] OR "Cardiotoxicity"[MeSH:NoExp] OR Cardiotox*[Title/Abstract] OR nephrotox*[Title/Abstract] OR immunotox*[Title/Abstract] OR hepatotox*[Title/Abstract] OR cytotox*[Title/Abstract] OR "Cytotoxicity, Immunologic"[MeSH:NoExp] OR immunocytotox*[Title/Abstract] OR intoxication[Title/Abstract] OR "Congenital, Hereditary, and Neonatal Diseases and Abnormalities"[MeSH Terms] OR "Treatment Failure"[MeSH Terms] OR "Case Reports”[Publication Type] OR case report*[Title/Abstract] OR "Environmental Exposure"[MeSH Terms] OR "Contraindications"[MeSH Terms] OR "Wounds and Injuries"[MeSH Terms] OR "Suicide"[MeSH:NoExp] OR suicide[Title/Abstract] OR "Poisoning"[MeSH Terms] OR "Drug Tolerance"[Majr] OR "Drug Resistance"[MeSH Terms] OR "Substance-Related Disorders"[MeSH Terms]) AND (inprocess[sb] OR medline[sb]) AND ("humans"[MeSH Terms] OR "humans"[All Fields] OR "human"[All Fields])

So that you can also use this search filter on Ovid, we have translated the PubMed syntax into Ovid MEDLINE syntax. Availing of the ABC format options behind Focused Searches, you can display the Ovid rendered version by clicking on ACTIONS / Display. Alternatively, ACTIONS / Launch will run the filter in Ovid MEDLINE. If you would like to talk to a member of the Ovid Training Team about the filter, select ACTIONS / Ovid Coaching. Once in the database you can combine the filter with substances relevant to your investigation. You can also save the filter in My Workspace for re-use as part of your own or institutional library of searches and search blocks. 

The accompanying Focused Search, Search Blocks in Line Format (EMA AE Filter) – Ovid MEDLINE (Part 2), will consider the relative merits of this filter in its paragraph format vis-à-vis a line-by-line format. 

Strategy

(exp “Drug-Related Side Effects and Adverse Reactions”/ OR adverse drug reaction.ti,ab,kf. OR ae.xs OR adverse.ti,ab,kf. OR side effects.ti,ab,kf. OR side effect.ti,ab,kf. OR exp drug overdose/ OR drug overdose.ti,ab,kf. OR drug overdose*.ti,ab,kf. OR exp drug misuse/ OR drug misuse.ti,ab,kf. OR misus*.ti,ab,kf. OR exp Substance-Related Disorders/ OR drug abuse.ti,ab,kf. OR substance abuse.ti,ab,kf. OR abus*.ti,ab,kf. OR exp pregnancy/ OR pregnancy.ti,ab,kf. OR pregnan*.ti,ab,kf. OR exp Pregnancy Complications/ OR exp Lactation/ OR exp Breast Feeding/ OR (exp Milk, Human/ AND exp Bodily Secretions/) OR exp Fertility/ OR exp Reproduction/ OR exp Fetus/ OR exp Embryonic Structures/ OR Teratogens/ OR Teratogenesis/  OR terato*.ti,ab,kf. OR drug efficacy.ti,ab,kf. OR exp Substance Withdrawal Syndrome/ OR exp Medication Errors/ OR exp Death/ OR death*.ti,ab,kf. OR Fatal Outcome/ OR fatal*.ti,ab,kf. OR exp Drug Interactions/ OR Drug Interaction*.ti,ab,kf. OR Carcinogens/ OR carcinogen*.ti,ab,kf. OR Mutagens/ OR Mutagenesis/ OR mutagen*.ti,ab,kf. OR exp "Off-Label Use"/ OR exp Occupational Exposure/ OR to.fs OR toxic*.ti,ab,kf. OR pharmacotox*.ti,ab,kf. OR Neurotoxicity Syndromes/ OR Neurotox*.ti,ab,kf. OR Cardiotoxicity/ OR Cardiotox*.ti,ab,kf. OR nephrotox*.ti,ab,kf. OR immunotox*.ti,ab,kf. OR hepatotox*.ti,ab,kf. OR cytotox*.ti,ab,kf. OR Cytotoxicity, Immunologic/ OR immunocytotox*.ti,ab,kf. OR intoxication.ti,ab,kf. OR exp "Congenital, Hereditary, and Neonatal Diseases and Abnormalities"/ OR exp Treatment Failure/ OR case reports.pt. OR case report*.ti,ab,kf. OR exp Environmental Exposure/ OR exp Contraindications/ OR exp "Wounds and Injuries"/ OR Suicide/ OR suicide.ti,ab,kf. OR exp Poisoning/ OR exp *drug tolerance/ OR exp Drug Resistance/ OR exp Substance-Related Disorders) AND (in process.st. or medline.st.) AND (exp "humans"/ OR "humans".af OR "human".af)

A look at the relative merits of search filters in a paragraph format vis-à-vis a line-by-line format, using as an example the EMA AE Filter for Ovid MEDLINE (Part 2).

Background

Generally speaking, search filters, whether displayed on screen or reported in scientific literature come in three formats. These are, firstly the “line-by-line” format where search expressions are entered or displayed as a list, one on top of the other, literally line by line. The second format, here referred to as the “paragraph” format has all the search expressions bundled into a single line that appears as a block of text. This provides for a more compact display, and can in turn, be also run as a single line search. Thirdly, the “hybrid” format describes search strategies that contain a mixture of line-by-line and paragraph format search expressions.

Opting for one format over another depends upon many factors. These vary from available screen space to the capacity of the reporting vehicle, e.g. a printed journal, to simply personal choice.

The purpose of this Focused Search is to raise a note of caution when using the paragraph format without firstly verifying whether or not the search expressions (a). run in the target database, and (b). are relevant to the task at hand. The AE Filter as shown above, unpacked, extends to 78 lines listed line-by-line. This way the relative presence of the terms and phrases can be more easily assessed. As too can be the balance between free term and thesaurus-based searches, and with respect to the latter,  whether they have been exploded. Using Ovid’s Edit function (Actions / More / Edit) a thesaurus expression can have the “exp” command function deleted or added to see what a difference this makes.

It is recommended that your key search filters be saved and stored in both paragraph and line-by-line formats. The former for ease of execution and display. The latter for verification, updating and overall knowledge asset management. 

Ovid Trainer Tips

• Command line Syntax: Lists of search expressions can be neatly combined using the OR operator as displayed in line #74 above, i.e. or/1-73.
• Ovid Search History Launcher Tool: Having unpacked a paragraph formatted search using for example, Notepad, the resulting list of search expressions can be easily imported into Ovid using the Ovid Search History Launcher Tool. See https://tools.ovid.com/ovidtools/launcher.html .
• Share Search History: Conversely, searches regardless of format can be exported from Ovid into other applications for eventual re-use, for peer review and reporting purposes. Located in the Search History section of the Ovid interface, the three Share Search History options are, Email All Search History, Copy Search History Link and Copy Search History Details.

Strategy

exp "Drug-Related Side Effects and Adverse Reactions"/

adverse drug reaction.ti,ab,kf.

ae.xs.

adverse.ti,ab,kf.

side effects.ti,ab,kf.

side effect.ti,ab,kf.

exp drug overdose/

drug overdose.ti,ab,kf.

drug overdose*.ti,ab,kf.

exp drug misuse/

drug misuse.ti,ab,kf.

misus*.ti,ab,kf.

exp Substance-Related Disorders/

drug abuse.ti,ab,kf.

substance abuse.ti,ab,kf.

abus*.ti,ab,kf.

exp pregnancy/

pregnancy.ti,ab,kf.

pregnan*.ti,ab,kf.

exp Pregnancy Complications/

exp Lactation/

exp Breast Feeding/

exp Milk, Human/ and exp Bodily Secretions/

exp Fertility/

exp Reproduction/

exp Fetus/

exp Embryonic Structures/

Teratogens/

Teratogenesis/

terato*.ti,ab,kf.

drug efficacy.ti,ab,kf.

exp Substance Withdrawal Syndrome/

exp Medication Errors/

exp Death/

death*.ti,ab,kf.

Fatal Outcome/

fatal*.ti,ab,kf.

exp Drug Interactions/

Drug Interaction*.ti,ab,kf.

Carcinogens/

carcinogen*.ti,ab,kf.

Mutagens/

Mutagenesis/

mutagen*.ti,ab,kf.

exp "Off-Label Use"/

exp Occupational Exposure/

to.fs.

toxic*.ti,ab,kf.

pharmacotox*.ti,ab,kf.

Neurotoxicity Syndromes/

Neurotox*.ti,ab,kf.

Cardiotoxicity/

Cardiotox*.ti,ab,kf.

nephrotox*.ti,ab,kf.

immunotox*.ti,ab,kf.

hepatotox*.ti,ab,kf.

cytotox*.ti,ab,kf.

Cytotoxicity, Immunologic/

immunocytotox*.ti,ab,kf.

intoxication.ti,ab,kf.

exp "Congenital, Hereditary, and Neonatal Diseases and Abnormalities"/

exp Treatment Failure/

case reports.pt.

case report*.ti,ab,kf.

exp Environmental Exposure/

exp Contraindications/

exp "Wounds and Injuries"/

Suicide/

suicide.ti,ab,kf.

exp Poisoning/

exp *drug tolerance/

exp Drug Resistance/

exp Substance-Related Disorders/

or/1-73

(in process or medline).st.

74 and 75

exp "humans"/ or "humans".af. or "human".af.

76 and 77

Development and validation of PubMed and Ovid MEDLINE search filters for exposure pathways linking climate change with human health

Background

Climate Change Search Filters - 99% sensitivity cutoff

1. Air quality

exp Fires/ or exp Particulate Matter/ or exp Air Pollution/ or exp Smoke/ or (wildfire* or PM10 or PM 10 or PM2 or air pollution or air quality or "PM 2.5" or ozone or weather or pollutant* or humid* or ambient or asthma).ti,ab.

Click < here > to run in Ovid MEDLINE ALL <1946 to Present>.

2. Extreme weather events

Floods/ or Cyclonic Storms/ or exp Disasters/ or exp Climate/ or (river* or hurricane* or flood* or disaster* or drought* or weather or rainfall*).ti,ab.

Click < here > to run in Ovid MEDLINE ALL <1946 to Present>.

3. Food supply and safety

Child Nutrition Disorders/ or Cholera/ or exp Rain/ or exp Food Supply/ or Droughts/ or exp Salmonella Infections/ or exp Foodborne Diseases/ or Food Microbiology/ or Seasons/ or (salmonellos* or stunt* or drought* or underweight or foodborne or malnutrition or weather or salmonella*).ti,ab.

Click < here > to run in Ovid MEDLINE ALL <1946 to Present>.

4. Heat stress

Extreme Heat/ or exp Heat Stress Disorders/ or exp Hot Temperature/ or Seasons/ or exp Climate/ or (daily mortality or heat wave* or heat related or extreme heat or heatwave* or weather or meteorologic* or ambient temperature* or climate change or air pollution or summer* or climate* or hot or high temperature* or ambient).ti,ab.

Click < here > to run in Ovid MEDLINE ALL <1946 to Present>.

5. Vector distribution and ecology

Rain/ or Climate/ or Insect Vectors/ or Climate Change/ or Seasons/ or transmission.fs. or Disease Outbreaks/ or (rain* or mosquito* or climat* or humi* or borne or endemic* or epidemic* or fever or vector* or surveillan*).ti,ab.

Click < here > to run in Ovid MEDLINE ALL <1946 to Present>.

6. Water quality and quantity

Cholera/ or Floods/ or exp Vibrio cholerae/ or Water Microbiology/ or exp Water Supply/ or exp Disasters/ or exp Climate/ or (heavy rain* or waterborne or rainfall* or flood* or diarrh* or cholera* or season*).ti,ab.

Click < here > to run in Ovid MEDLINE ALL <1946 to Present>.

See also the same search but in the line-by-line format: 

Cholera/ 
Floods/ 
exp Vibrio cholerae/ 
Water Microbiology/ 
exp Water Supply/ 
exp Disasters/ 
exp Climate/ 
heavy rain*.ti,ab.
waterborne.ti,ab.
rainfall*.ti,ab. 
flood*.ti,ab. 
diarrh*.ti,ab. 
cholera*.ti,ab.
season*.ti,ab.

Click < here > to run in Ovid MEDLINE ALL <1946 to Present>.

Strategy

exp Fires/ or exp Particulate Matter/ or exp Air Pollution/ or exp Smoke/ or (wildfire* or PM10 or PM 10 or PM2 or air pollution or air quality or "PM 2.5" or ozone or weather or pollutant* or humid* or ambient or asthma).ti,ab.