airway hyperresponsivness bronchoconstriction reversible airway obstruction

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Asthma and COPD January 6, 2010

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Page 1: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Asthma and COPD January 6, 2010

Page 2: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Airway hyperresponsivness

Bronchoconstriction

Reversible airway obstruction

Page 3: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Early asthmatic responseResult of release of preformed

mediators to airway stimulus

Late asthmatic response4-6 hours later as a result of

generation and recruitment of other inflammatory mediators in response to airway stimulus

Page 4: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Case 1 28 yo female

Known asthmatic

On ventolin inhaler (using every 2-3 hours – 1 puff)

Seasonal allergies, Diabetes Type 1 (insulin)

Cough and runny nose 3 days (nocturnal cough)

36.7oC, 110bpm, RR36, 120/80, 94% RAO2, 5.7mM

Short sentences, SCM use

BS decreased to bases, expiratory wheezes

PEFR 60%

Page 5: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

No clinical sign is good enough by itself

Clinical findings correlate poorly with severity of airway obstructionTachypnea (RR>40)Accessory muscle useTachycardia (HR >120bpm)Pulsus paradoxus Upright position/inability to lie supineSweatingDifficulty finishing sentencesCyanosis Decreased LOC“Quiet chest”

Page 6: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Risk factors for death in Asthma

>2 hospitalizations in the past year for asthma >3 ED visits in the past year for asthma Hospitalization/ED visit in past month for asthma Current/recent systemic steroid use >2 canisters of beta-agonist use in the past month Difficulty perceiving severity of airway obstruction ICU/intubation for asthma Low socioeconomic status Significant psychosocial issues Illicit drug use Cardiac comorbidity Chronic lung disease Severe psychiatric Illness

Page 7: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Any objective measures?What is your objective measure of choice?

Peak expiratory flow rate (PEFR) vs FEV1

Spirometry is the gold standard for diagnosing and categorizing severity of airflow limitation in obstructive lung disease

We don’t have ready access to spirometry in the emergency department (RTs have machine in their office but need to carry it up)

We do have ready access to Peak Flow Meters for PEFR measurements

Page 8: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

PEFR and FEV1 not interchangeable

Aggarwal AN, Gupta D, Jindal SK. The relationship between FEV1 and peak expiratory flow in patients with airways obstruction is poor. Chest. 2006 Nov;130(5):1454-61. Cross-sectional, retrospective study 6,167 adult patients showing obstructive pattern

on spirometry over a 6-year period

“we found that in patients with severe airway obstruction (FEV1 < 40% of predicted), PEF% overestimated FEV1 %, whereas exactly the opposite happened in patients with less severe airway obstruction”

Page 9: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Correlation is better in Severe asthma (FEV <40%)

The greatest utility of PEFR measurements is response to treatment

Page 10: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Asthma PathwayOne exists for adults! (for those with known

asthma) Oxygen PEFR pre-treatment Ventolin by MDI Atrovent (ipratropium bromide) by MDI Prednisone PEFR post-treatment

Page 11: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

What diagnostic tests are people doing?

Blood tests rarely indicated

CXR rarely indicated (only to look for superimposed infection or complications)

ABGs rarely indicated

Page 12: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

TreatmentOxygen

Beta-agonists No difference between MDI vs nebulizers

Hospital admissions, time in ED, PEFRSide effects: change in RR, heart rate

Anticholinergics Synergy with beta-agonist treatment for

Decreasing hospital admissions (NNT = 14) Increasing PEFR

Especially in those with severe asthma, multiple doses of anticholinergics

Page 13: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

TreatmentCorticosteroids

Reduce hospital admissions (NNT = 8)NNT = 5 in severe asthma

Improve PEFR Reduce rates of relapse at 7-10 days Reduce number of relapses requiring admission Reduce beta-agonist use

Page 14: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Re-assessmentCalled back to the bedside, patient done

treatment, RAO2 88%

O/E: Feels better A/E better, faint wheeze on full end expiration Decreased work of breathing

What do you want to do?

Why is the RAO2 worse?

Page 15: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

What if this patient was pregnant?

Conflicting studies Possible IUGR, preterm delivery, preeclampsia in

those with poorly controlled asthma Therapy as is

Potential harmful role of systemic epinephrine on uterine vasoconstriction

Page 16: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Discharge Instructions? Discharge Medications?

2 puffs ventolin q4-6h depending on symptoms

Return to ER if >16 puffs day

Check sugars more frequently (QID) because of corticosteroids WHAT ARE STAFF IN THE ROOM DOING?

When do you prescribe something in addition to their Ventolin? WHAT ARE STAFF IN THE ROOM DOING? If using SABA >2days/week, add low dose corticosteroid (Flovent) If using SABA daily, add low dose corticosteroid + LABA

(Advair/Symbicort)

Referral to Calgary COPD & Asthma Program Spirometry, Education, Smoking Cessation, Action Plan

Page 17: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Case 2 RAPID call from High River

18yo male with known asthma

1 week of increasing wheezing, shortness of breath, cough

Increasing ventolin use, 2 puffs every hour since yesterday

Meds: Ventolin, Advair, Singulair

Past Med Hx: 2 asthma ED visits last year, 1 admission at age 15 (+ICU/not intubated)

Smoker

Vitals: 37.2oC, RR40, 132bpm, 130/88, 85% on 10L O2 by mask

Shallow fast breathing, minimal wheezes, very minimal air entry, drowsy

Page 18: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

What they’ve done in High River

Ventolin X 3 back to back

Atrovent X 3 back to back

Prednisone 60 mg

High flow oxygen on non-rebreather mask

CXR – no infiltrate, no pneumothorax

ABG – 7.24/60/85/23

What do you tell them to do?

Page 19: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

MagnesiumRowe et al. Magnesium sulfate for treating

exacerbations of acute asthma in the emergency department. Cochrane Airways Group Cochrane Database of Systematic Reviews. 2000.

Pooled study results show no significant difference

Reduces hospitalizations and improves pulmonary function scores in those with “severe” asthma Severe asthma defined as PEFR < 25% post-

treatment with beta-agonists

Page 20: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Epinephrine Epinephrine – B2 effects, but also alpha effect: decreased

airway edema, inflammation, and secretions. Alpha may cause bronchoconstriction.

Nebulized epinephrine not any better than nebulized ventolin Plint et al. 2000. Prospective RCT - No difference in pulmonary

index score, O2 sat, O2 requirements, admission rates, length of ED stay, length of hospital stay

SC epinephrine equivalent to nebulized beta-agonist in in mild/moderate asthma Sharma and Madan 2001 Indian Journal of Pediatrics Vol 68.

Prospective randomized study SC epinephrine equivalent to nebulized salbutamol on PEFR Excluded severe asthmatics – therefore not useful to our severe

patient population

Page 21: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Epinephrine IM epinephrine

No evidence for IM epinephrine Extrapolated from SC data/Anaphylaxis data

IV epinephrine No evidence for IV epinephrine Theoretical benefits and used only in severe

refractory cases Serious adverse events are somewhere <4%

SVT, chest pain with ECG changes, increased TnT, hypotension

Putland et al. 2006. Vol 47(6) Annals of Emergency Medicine

Page 22: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Intravenous VentolinTravers et al. 2002 Systematic Review

Looked at population with ‘severe’ asthma (defined differently – HR, pulmonary index scores, PFT) in EDs. No benefit for IV beta-agonists compared to nebulized beta agonists with non-statistically significant increase autonomic adverse effects, but no data on IV in addition to inhaled.

3 of 9 studies in children

Page 23: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Leukotriene InhibitorsStudies showing modest improvements in PEFR

but no effect on hospitalizations We also do not have the IV montelukast or PO

zafirlukast on our formulary used in the studies

Page 24: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Methylxanthines Not recommended (Evidence A)

National Asthma Education and Prevention Program: Expert Panel Report III. 2007

Cochrane Review: Parameswaran et al. 2000No statistical signficance airflow outcomes More palpitations/arrhythmias

Page 25: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

HelioxCochrane Review: Rodrigo et al. 2010

10 trials, 544 patientsNo significant difference in PFTs, admissions to

hospitalSignificant difference in PFT in severe

subgroup (N = 3, SMD 0.61; 95% CI 0.21 to 1.00)

Page 26: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Back to the patient It’s now been 1 hour since the patient received the

back-to-back ventolin/atrovent and steroids

Vitals: 37.2oC, RR38, 126bpm, 130/88, 83% on 10L O2 by mask

Shallow fast breathing, minimal wheezes, very minimal air entry, drowsy (but less so than before)

ABG – 7.24/60/85/23 and Pulse oximeter reading 85%

You’re working with Arun, explain the ABG/O2 discrepancy

Page 27: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Would anyone BiPAP this patient?

Cochrane Review, Ram et al. 2005 1 study, N=30 BiPAP (8/5 to 15/3 max) vs Sham (1/1 with holes

in tube) No intubations, deaths Decreased hospital admissions, PEFR, RR No difference treatment failure, length of ICU

stay, heart rate

Since then, only one study has come out looking at BiPAP in place of bronchodilators in mild/moderate asthma

WHAT IS STAFF EXPERIENCE WITH BIPAP?

Page 28: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

How would you intubate this patient?

Ketamine

Succinycholine

Page 29: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

How would you set your ventilator settings?

FiO2 100%

RR 6-8

Small tidal volumes 6-8cc/kg (partly guided by evidence in ALI)

Long expiratory times (I:E ratio > 1:2)

PEEP < 5 cm H20 (start with 0)

Target plateau pressures < 20 cm H20

Oxygenation > 90%

Permissive hypercapnea (pH >7.20) to prevent barotrauma

Page 30: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Once intubated, patient becomes hypotensive and O2 sats decreasing

What do you do? Disconnect the patient from the ventilator Decompress the Chest Consider bilateral chest tubes Fluid bolus Suction tube

Page 31: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

COPD

Page 32: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

DefinitionInflammatory lung disease with

progressive airflow limitation that is not fully reversible

Page 33: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Case 151 yo female smoker with 2 days increasing cough,

shortness of breath, and sputum production.

Med Hx: COPD (no home O2), HTN, hard of hearing

Meds: Ventolin, Spiriva

No allergies

No chest pain, CHF symptoms, fever/chills

O/E: 375, 139 bpm, RR 36, 210/120,221/123, 45% on RA02,

72% on NRB, 10.5mM

Page 34: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Case 1 Physical ExamAlert, answering appropriately in short phrases

Anxious

Central and peripheral cyanosis

++accessory muscle use

Decreased breath sounds throughout

Inspiratory and expiratory wheezes throughout

No extra heart sounds, pulses equal bilat, no edema

Page 35: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

What is your definition of AECOPD?

Acute exacerbation of COPD A change in the patient’s dyspnea, cough, or

sputum that is beyond normal day-to-day variation

Page 36: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Investigations Bloodwork usually not helpful

PFTs not as helpful as in asthma; majority of disease is non-reversible

Arterial Blood Gas usually not helpful unless Unable to obtain O2 sat

Severe exacerbation Hospitalization Prior to NIPPV

CXRay Helpful in decision making and ruling out DDx Changes management in ~15-20% cases

What would you expect to see on an ECG? ECG

Right axis deviation, RVH, Right atrial enlargement, low voltage Atrial arrhythmias are most common: A. Fib, MAT

Page 37: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Results of InvestigationsCBC: Hgb 199, WBC 21.2 (Neuts 18.6), Plt 215

Electrolytes: Na 141, K 4.7, Cl 95, HCO3 28

Creatinine 101

TnT < 0.03

CXRay – extensive bilateral nodularity with confluent opacities at lung bases

ABG: 7.31/56/80/27 – What is her normal PCO2?

Page 38: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

TreatmentOxygen – to maintain saturation ~90%

Bronchodilators Beta-agonists are first-line

Improve airway function/reduce hyperinflation Anticholinergics

No difference when compared with beta-agonistsMinimal evidence for synergistic effect with beta-

agonist, but we add it anyways to avoid intubation

Page 39: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

TreatmentCorticosteroids

Moderate/Severe AECOPD (Evidence 1A)dose/duration/type needs to be individualized

7 to 10 days recommended (GOLD Guidelines 2009)

Cochrane Review: Walters et al. 200910 RCTs, 1051 patientsFewer treatment failures within 30 days (NNT = 10)Decreased duration hospitalization Improved FEV1, breathlessness, blood gas valuesNo effect on mortalityIncreased adverse events (NNH = 6)

Adverse events: hyperglycemia, increased appetite, weight gain, insomnia

Page 40: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Who do you give antibiotics to?

3 of 3 for: dyspnea, sputum volume, sputum purulence

Sputum purulence if accompanied by dyspnea or sputum volume

Mechanical ventilation

NNT mortality = 8

NNT treatment failure = 3

Adverse effects: Increased diarrhea

Page 41: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Which antibiotics?Dimopoulos et al. 2007. Comparison of

first-line with second-line antibiotics for acute exacerbations of chronic bronchitis. Chest; 132:447-455More treatment failures with 1st line Abx VS

2nd line Abx (OR 0.51, 95% CI 0.34 to 0.75)No differences in adverse effects

Page 42: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

What antibiotics?Depends on the presence of high risk features:

Severe COPD Recent antibiotic use (<3 months) Frequent exacerbations (>3/year) Presence of comorbid disease

No and mild exacerbation? B-lactam/B-lactamase inhibitor, tetracycline, TMP-

SMX, macrolide, 2nd/3rd generation cephalosporin

Yes or >moderate exacerbation? B-lactam/B-lactamse inhibitor, floroquinolone,

2nd/3rd generation cephalosporin

Page 43: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Who would BiPAP this patient?

Indications for NIPPV Moderate to severe dyspnea

RR>25Accessory muscle useParadoxical abdominal breathing

Moderate severe acidosis pH < 7.35PaCO2 > 45

Page 44: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Which patients would you not BiPAP?

Exclusion Criteria Systemic

Respiratory arrest Hemodynamic instability (hypotension, arrhythmia, MI) Change in mental status/uncooperative patient

Anatomic High aspiration risk Copious/viscous secretions Recent facial/GI surgery Craniofacial trauma Fixed nasopharyngeal abnormality Extreme obesity Burns

Page 45: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

What does BiPAP do for you?

Cochrane Review, Ram et al. 2004 Respiratory failure patients due to AECOPD with PaCO2

>45 Excluded patients with primary diagnosis of pneumonia 14 studies (758 patients)

Outcomes Decreased mortality (NNT 10) Decreased need for intubation (NNT 4) Decreased treatment failures (NNT 5) More rapid improvement in first hour of pH, PaCO2, RR

Decreased complications associated with treatment Decreased hospital length of stay (pH<7.30 subgroup

only)

Page 46: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

When is BiPAP failing?NIPPV Failure

Lethargy Exhaustion Worsening respiratory rate Worsening oxygen saturation Speechlessness Paradoxical abdominal breathing

Page 47: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Back to our patientAfter 3 hours on BiPAP

Repeat ABG: 7.34/53/74/27 with markedly improved work of breathing. Having conversations in full sentences No longer cyanotic

Page 48: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

Not recommended Methylxanthines

No difference FEV1 No difference hospital admissions/length of stay No difference relapses Increased adverse effects with methylxanthine

Heliox (insufficient evidence to support use) No clinical outcomes reported (mortality, intubation)

Improved peak inspiratory flow rate Decreased PaCO2

Decreased dyspnea scores

Respiratory Stimulants Doxapram

Improved blood gas exchange in first few hours of treatment, but NIPPV may be more effective

Page 49: Airway hyperresponsivness Bronchoconstriction Reversible airway obstruction

What is your approach to intubating this patient?

Much the same as intubating the asthma patient Want to avoid intubation if possible Same RSI technique Same ventilator settings

Want to avoid hyperventilation alkalosis These patients usually have metabolic alkalosis

(compensation for chronic respiratory acidosis) Can result in seizures, dysrhythmias