Heart, lung, and acute care
Peripheral Artery Disease and the Ankle-Brachial Index
Recognize peripheral artery disease: what claudication feels like, why legs ache when walking, and how the ankle-brachial index confirms it.
Health & Evidence Library
Heart, lung, and acute care
Evidence guides on cardiovascular and respiratory health, acute symptoms, diagnostic safety, and recovery after serious illness.
50 guides · Page 1 of 1
Heart, lung, and acute care
Atrial Fibrillation: Rate Control, Rhythm Control, and Early Rhythm Control
How rate control, rhythm control, and early rhythm control differ in atrial fibrillation, what EAST-AFNET 4 changed, and how the choice is made.
Heart, lung, and acute care
Cold, Flu, COVID, or RSV: How These Illnesses Are Told Apart
Flu, COVID, colds, and RSV overlap heavily. Compare symptoms, testing, and how long each stays contagious, plus when to test and seek care.
Heart, lung, and acute care
Acute Bronchitis and the Cough That Lingers
Acute bronchitis is almost always viral. The cough can last up to three weeks, and antibiotics rarely help. Here is the evidence and the red flags.
Heart, lung, and acute care
Who Should Be Tested for Alpha-1 Antitrypsin Deficiency?
Testing for alpha-1 antitrypsin deficiency belongs in routine COPD care and several lung, liver, skin, vascular, and family settings.
Heart, lung, and acute care
What Troponin Measures, and Why a High Result Is Not a Diagnosis
Cardiac troponin detects heart-muscle injury. A heart attack diagnosis also requires a changing pattern and evidence of ischemia.
Heart, lung, and acute care
What the Vaping Lung Injury Outbreak Taught Us About Causation
The EVALI investigation linked vitamin E acetate in THC vaping products to lung injury through epidemiology, product tests, and lung-fluid analysis.
Heart, lung, and acute care
What the Fleischner Rules Say About an Incidental Lung Nodule
Fleischner guidance uses nodule size, solidity, number, and cancer risk to limit unnecessary follow-up while finding nodules that need closer evaluation.
Heart, lung, and acute care
What the FEV1/FVC Ratio Actually Measures on a Spirometry Report
FEV1/FVC describes how much of a forced breath leaves in the first second. It detects obstruction but does not name the cause or severity alone.
Heart, lung, and acute care
What the DLCO Test Reveals About Gas Transfer
DLCO estimates how readily carbon monoxide moves from inhaled gas into blood. Learn what lowers or raises it, how technique matters, and why KCO differs.
Heart, lung, and acute care
What the Apnea Hypopnea Index Does and Does Not Tell You
The apnea hypopnea index counts breathing events per hour of sleep. It does not fully measure oxygen stress, symptoms, sleep disruption, or individual risk.
Heart, lung, and acute care
What Lipoprotein(a) Measures and Why It Matters
Lipoprotein(a) is an inherited apoB particle linked to atherosclerotic disease and aortic stenosis. Learn testing, units, interpretation, and limits.
Heart, lung, and acute care
What Ejection Fraction Measures
Ejection fraction is the percentage of a ventricle's filled volume pumped out with each beat. Learn what it measures, how methods differ, and what it misses.
Heart, lung, and acute care
What BNP and NT-proBNP Measure
Learn what BNP and NT-proBNP reflect, how they help evaluate heart failure, and why age, kidney function, obesity, rhythm, medicines, and setting matter.
Heart, lung, and acute care
Why Sleep Apnea Screening Received an I Statement
Why the USPSTF found insufficient evidence for screening adults without recognized symptoms, despite available questionnaires and treatment.
Heart, lung, and acute care
Why Reliever-Only Asthma Treatment Was Abandoned
Why treating asthma with a short-acting bronchodilator alone no longer meets current GINA safety standards and what replaced it.
Heart, lung, and acute care
Why Lung Function Reference Equations Are Removing Race
Why laboratories are adopting race-neutral lung function equations, what changes on a spirometry report, and why clinical context still matters.
Heart, lung, and acute care
What a Coronary Calcium Score Means
A coronary calcium score measures calcified coronary plaque and can refine preventive treatment decisions when estimated cardiovascular risk is uncertain.
Heart, lung, and acute care
TAVR Versus SAVR in Low-Risk Aortic Stenosis
Low surgical risk does not make TAVR and surgery interchangeable. Learn how long-term trials, anatomy, valve durability, and lifetime planning shape the choice.
Heart, lung, and acute care
Statin Intolerance and the Nocebo Effect
Blinded n-of-1 trials show that symptoms are real while their timing often cannot distinguish statin effects from placebo and background symptoms.
Heart, lung, and acute care
Why How Your Blood Pressure Is Measured Changes the Diagnosis
How office technique, home readings, and 24-hour monitoring can each decide a hypertension diagnosis, and what the 2025 AHA/ACC guideline changed.
Heart, lung, and acute care
What the LoDoCo2 Trial Says About Low-Dose Colchicine for Residual Cardiovascular Risk
A plain-language appraisal of LoDoCo2, the trial testing daily 0.5 mg colchicine for residual cardiovascular risk in chronic coronary disease.
Heart, lung, and acute care
The 0.70 Cutoff in COPD Diagnosis: Fixed Ratio Versus Lower Limit of Normal
Why GOLD keeps a fixed FEV1/FVC below 0.70 for COPD, and where it overdiagnoses older adults and underdiagnoses younger ones versus LLN.
Heart, lung, and acute care
STRONG-HF and the Four Pillars: What the Trial Really Tested About Heart-Failure Therapy
What the STRONG-HF trial tested about rapid up-titration of heart-failure drugs, why it stopped early, and how to read speed and sequencing claims.
Heart, lung, and acute care
How to Read ARISTOTLE: Apixaban Versus Warfarin in Atrial Fibrillation
A plain-language appraisal of the ARISTOTLE trial and the ordered testing plan that let a non-inferiority study report apixaban as superior to warfarin.
Heart, lung, and acute care
How the Evidence Separates COPD From Asthma
Why no single test tells COPD from asthma, and how history, spirometry, and bronchodilator response combine to sort them out.
Heart, lung, and acute care
How Researchers Define a Moving Target Called Long COVID
Why the broad 2024 NASEM clinical definition and the narrower NIH RECOVER symptom score disagree about who has Long COVID, and what that means for research.
Heart, lung, and acute care
How LDL Targets Are Set in the 2026 Cholesterol Guideline
How the 2026 ACC/AHA dyslipidemia guideline turns trial data into risk-based LDL goals and a statin, ezetimibe, PCSK9 treatment cascade.
Heart, lung, and acute care
How Idiopathic Pulmonary Fibrosis Is Diagnosed and Slowed
How the 2022 ATS/ERS/JRS/ALAT guideline diagnoses IPF from the UIP pattern and multidisciplinary discussion, and how antifibrotics slow FVC decline.
Heart, lung, and acute care
How Biomarkers Pick a Biologic for Severe Asthma
How blood eosinophils, FeNO, and IgE map type 2 airway inflammation and steer the choice among anti-IL-5, anti-IL-4/13, anti-IgE, and anti-TSLP biologics.
Heart, lung, and acute care
How a High-Sensitivity Troponin 0/1-Hour Rule-Out Pathway Works
What a 0/1-hour high-sensitivity troponin pathway measures, why one hour is enough, and how to read the 99 percent sensitivity and NPV claims.
Heart, lung, and acute care
Home Oxygen for COPD: What the Trials Actually Show
Home oxygen extends COPD survival only in severe resting hypoxemia; the 2016 LOTT trial found no benefit for moderate desaturation.
Heart, lung, and acute care
Heart Failure With Preserved Versus Reduced Ejection Fraction
What ejection fraction tells you about heart failure, why the preserved type is harder to diagnose, and why the two types have such different proven treatments.
Heart, lung, and acute care
Does Treating Sleep Apnea Prevent Heart Attacks?
A randomized trial (SAVE) found CPAP did not cut heart attacks, despite strong observational links between sleep apnea and heart disease. Here is why.
Heart, lung, and acute care
Does Pulmonary Rehabilitation Work for COPD? Reading the Trial Evidence
A physician reads the Cochrane trial evidence on pulmonary rehabilitation for COPD, and why the benefits are large enough to feel.
Heart, lung, and acute care
Does Adding a Second Drug to Your Statin Prevent More Heart Attacks? What the Trials Show
Whether adding ezetimibe or a PCSK9 inhibitor on top of a statin actually prevents cardiovascular events, and how big the benefit really is.
Heart, lung, and acute care
Do Inhaled Steroids Help Every COPD Patient? What Blood Eosinophils Predict
Blood eosinophil counts help predict which COPD patients benefit from inhaled steroids, and where the GOLD treatment thresholds came from.
Heart, lung, and acute care
Did Triple Inhaler Therapy Really Lower COPD Deaths?
Reading the ETHOS and IMPACT mortality signal honestly, and why the comparator, not the third drug, drives the result.
Heart, lung, and acute care
When to call emergency services without hesitating
The situations where calling for emergency help is clearly the right move, and why hesitation is the common, avoidable mistake that costs the most.
Heart, lung, and acute care
When chest pain is an emergency, and when to call for help
How to think about chest pain, the features that mean call for help now, and why you should not wait or drive yourself to the hospital.
Heart, lung, and acute care
Sepsis: the emergency many people have never heard of
What sepsis is, the warning signs to know, and why recognizing it early and seeking emergency care quickly can be lifesaving.
Heart, lung, and acute care
Recognizing a stroke: why every minute matters
The FAST warning signs of a stroke, the other symptoms to know, and why calling for emergency help immediately can save a life and a future.
Heart, lung, and acute care
Heat and cold emergencies: recognition and response
How to tell heat exhaustion from heat stroke and hypothermia from frostbite, what to do for each, and the red flags that mean call emergency services now.
Heart, lung, and acute care
Heart attack warning signs, including the easy-to-miss ones
The classic and the easily missed signs of a heart attack, why symptoms can differ between people, and why calling for help fast matters.
Heart, lung, and acute care
Fever in adults: when it is just a fever and when it is not
Most fevers in adults are not emergencies. Learn the red flags, like confusion, a stiff neck, or trouble breathing, that mean you should seek care fast.
Heart, lung, and acute care
ER, urgent care, or primary care: choosing the right one
A practical guide to where to go for what, the emergency red flags that always mean the ER, and how to choose calmly when it is not clear.
Heart, lung, and acute care
Controlling severe bleeding before help arrives
Practical first aid for serious bleeding: firm direct pressure, when a tourniquet helps, and why to call emergency services right away.
Heart, lung, and acute care
Common myths about emergencies and first aid
Gentle, evidence-based corrections to widespread first-aid myths, from nosebleeds and burns to CPR and stroke, with what current guidelines actually advise.
Heart, lung, and acute care
Choking and CPR: awareness that can save a life
What to do when someone is choking, the basics of Hands-Only CPR, and why a hands-on certified course is the thing that truly prepares you.
Heart, lung, and acute care
Anaphylaxis and severe allergic reactions
How to recognize a severe allergic reaction, why epinephrine is the first and most important treatment, and why to call for emergency help every time.