Transcript Respirology - Dr. Peter McLeod

Arterial Blood gas
interpretation
 pH
 pH
PaCO2 PO2 on FIO2 =….
then PCO2 for acid-base balance
– for an acute change in PCO2 of 10, the pH
goes 0.08 units in the other direction.
 PCO2
and PO2 and FIO2 for gas
exchange
Examples of AcidBase Imbalance:
Bicarbonate is never
measured, it is calculated
from the HendersonHesselbach equation using
measured pH and paCO2
Describe the Acid-Base Imbalance (1):
 pH=7.42,
 PaCO2
PCO2=48
is slightly high
 pH is on the alkaline side of normal
 This is most probably a
compensated metabolic alkalosis
Describe the Acid-Base Imbalance (2):
 pH=7.36,

PCO2=52
PaCO2 is high
 pH
is normal, but on the acid side of
7.40
 This
is most probably a
compensated respiratory acidosis
Describe the Acid-Base Imbalance (3):
 pH=7.20,
 pH
PCO2=52
is quite acid
 PaCO2 is less high than you expect
for a pure respiratory acidosis,
(PCO2 up by 12, pH should go down
by ~ .10 units)
 this is a mixed acidosis
Assessment of Gas Exchange:
 Question:
While breathing room air, a
comatose hyperpneic youth arrives in the
ER. He is pink. An ABG shows:
– pH=7.15; PCO2=20, PO2=95
 Acid-base
status? Acute Metabolic
Acidosis
 Are his lungs normal? NO as A-a DO2 is
The Flow-Volume loop
1
2
 A. Normal
– Identify
» 1 Peak flow rate
» 2 RV
» 3 TLC
 What
is B?
3
The Flow-Volume loop
 A.
Normal
 B.
Restrictive
 C.
Large airway
fixed obstruction
 D.
Small airways
variable obstruction
 E.
Extra-thoracic
variable obstruction
Exercise Testing: Stage I
Screening
 Quantitate
exercise capacity c.f.
predicted
 Assess oxygen saturation on
exertion
 Factors limiting Exercise
– Pulmonary Mechanics
– Pulmonary Vascular
– Cardiac or peripheral (including
unfitness)
– Anxiety
Inhaler Devices:
Dry powder inhalers (DPI) - (Diskus or
Turbuhaler or Handihaler)
 Pressurized
Metered Dose Inhalers(Freon-free) (HFA MDIs) eg Advair 250,
Qvar,Salbutamol, Mometasone
– pulmonary deposition may be
improved
– side-effects decreased
 Patients
still need careful instruction
in the use of any inhaler device
Inhaled Steroids: (IS)
 Fluticasone
(Flovent) , Budisonide
(Pulmicort), Ciclesonide (Alvesco)
 all have similar local side effects sore throat, thrush, dysphonia ( try a
spacer and do a swish, gargle and
spit) (Ciclesonide may be exception)
 Enough absorption to cause bruising
Inhaled Steroids (IS): Potential sideeffects if long-term, high dose therapy:
 Cataracts,
 Osteoporosis
– osteoporosis prevention may be
important with children on high dose IS,
but not adults.
– Inactivity due to uncontrolled asthma
promotes osteoporosis also
 Delayed
growth
 Adrenal insufficiency
Long-lasting B2 Agonists
(LABAs):
 Examples:
– Salmeterol (Serevent) 25 ug p ii bid
– Formoterol (Oxeze) 12 ug p i bid
 Second-line
drug for ongoing acute
bronchospasm despite optimal
inhaled steroids
 Decreases nocturnal exacerbations
 Does not eliminate the need for
short-acting B2-agonists
 Not a rescue medication
Combination IS/LABA:
 Examples:
– Advair discus(fluticasone + salmeterol
– Symbicort turbuhaler (budisonide +
formoterol
 Indication
in Asthma:
– When IS in doses of 500-1000 ug/day
are insufficient to eliminate frequent
rescue with SABAs
 Indication
in COPD:
– May increase interval between AECB .
Leukotriene Antagonists
 Montelukast
(Singulair) 10 mgm qhs
 Block leukotriene-derived mediators
(SRS-ALTC4 and LTD4, but not
prostaglandins
 Montelukast is accepted for children
down to age 6 years (5 mgm
strength)
 It is helpful in a minority of
asthmatics
Leukotriene Antagonists
 Role:
– a second line drug
– If inhaled steroids are insufficient to control
symptoms or are contra-indicated
– May help:
» ASA-sensitive individuals
» restore sense of smell (Systemic distribution)
» may be useful to prevent progressive asthma
 Side
effects - None
IgE Antagonists: Omalizumab (Xolair)
 Monoclonal
antibodies block action
of IgE on mast cell
 Effective if IgE levels are only
slightly elevated (500-1200)
 Monthly injection
 Extremely expensive ?$45,000/year
 Use if frequent need for oral steroids
despite optimum conventional Rx
and patient has drug plan or $$$
Acute asthma, ER management
Mild: B2 agonist; start IS
Moderate: add O2, oral steroids
Severe: add continuous B2 aersols,
Ipatropium, 100% O2
Near
death: add intubation,
ventilation, kitchen sink (Theophylline,
MgSO4, Halogenated anesthetic)
Discharge criteria: track record,
response to B2 agonists, prior
steroids, compliance
Chronic asthma management
 Minimal:
B2 agonist prn.
 Mild: add inhaled steroids
 Moderate :
– Leucotriene antagonist
– long lasting B2 agonist
– Short course oral prednisone
 Severe:
– add oral steroids dose large enough, duration
long enough to return patient to “personal
best”
– “Bronchial barbecue”- bronchial thermoplasty
Asthma Consensus Guidelines
Next edition
Treatment Continuum
?2009
**
µg
Additional Therapy
*
0
250
500
10001500
Short-acting ß2-agonist on demand
Environmental Control and Education
Very Mild
Mild
Moderate
Moderately Severe
Severe
Preclinical
Intermittent
Persistent
* ß2 agonist need < 3 times/week (excluding 1 dose/day before exercise)
** ICS dose required > 400-500 mcg/day (as beclomethasone equivalent)
LABAs,
LTRAs
?Pred.
Dose
Lower
COPD
 4%
of Canadians
 4th leading cause of death
 Over 40 years of age
 Mortality rate rising, especially for females
 Occasionally occupation causes COPD
COPD Guidelines
 Do
not screen asymptomatic smokers
 Assess with spirometry if symptomatic
–
–
–
–
Cough
SOBOE
wheeze
persisting colds
 FEV1/
 Do
FVC< .7
ABG if FEV1 <40% predicted
COPD-Assesment: (FEV1/ FVC< .7)

Mild– SOBOE if hurrying

>80%
50%<80%
Severe
– SOB on ADL
– Resp failure
– R CHF

FEV1% predicted
Moderate
– Stops after walk of few
minutes


Very Severe
– SOB at rest
30%<50%
<30%
Continuum of COPD Management
CTS guidelines, Canadian Respiratory J 2008;SuppA 15:1-8
COPD- Management
 Education
 Smoking
cessation
 Pharmacotherapy
 Regular exercise is part of therapyEducation!
 Inhaled steroids only for repeated
AECB responding to prednisone
Smoking Cessation
 Counseling
 If
patient is motivated to quit :
+/- Nicotine replacement (patch,
gum, etc) -(doubles success)
+/- Bupropion (Zyban) start 1week
prior to quit day (doubles success)
+/- Combination =4x as successful(40%non smokers after 1 year, c.f.
10%)
Champix (varenicline tartrate) –a
pseudonicotine new kid on the block
Champix (varenicline tartrate)
 Pseudonicotine
 ..more
effective than Bupropion initially
 Side efect nausea 15-30%
 Dose: (half in renal disease)
– .5 mgm qd x 3d
– .5mgm bid x 4 d then D/C cigarettes
– 1 mgm bid x 12 weeks
 Cost:
$3.37/day (~ to “patch”; c.f.
$1.84/day for Zyban)
Inhaled Anti-Cholinergics:
Tiotropium (Spireva)
 Useful
in COPD
– significant increase in Vital Capacity
– may help FEV1
 Supplants
Ipatropium (Atrovent) as
DPI
 No side effects (?glaucoma
exacerbation)
 Dose: 18 ug tablet DPI inhaled qAM
via Handihaler
 Not a limited use drug
COPD long-term management
- continued
 Bronchodilators
– B2 (SABA-> LABA)
– and/or Ipatropium/Tiotropium
 Steroids:
only 10% respond - document
response!
 Combination IS/LABA may increase
time between exacerbations
 Theophyllines: popularity fluctuates
 Annual Influenza vaccination
 ? Pneumovax q 5-10 years
COPD long-term management
- continued
 Long-term
O2 prolongs life:
– if PaO2= or<55 mmHg
– if SpO2= or<88%
– if pulmonary hypertension,
polycythemia, nocturnal desaturation
PaO2<60, SpO2<90
– Palliative grounds allowed
 Antibiotics
for purulent bronchitis –
Trimethoprim, Tetracycline, Clavulin,
Cefuroxime, Clarithromycin, respiratory
quinolone
COPD long-term management
- continued
 Rehabilitationcomplex)
 Breathing
exercise! (GOYA to
exercises (? unproven)
 Surgery:
– Lung Volume reduction
» extra 2 years survival
– Lung transplantation
» No longer smokes
» Even if alpha 1 pt.
» Patient not on a ventilator
» Median survival 2-4years
AECB= Acute exacerbation of
Chronic Bronchitis
 Over
50% associated with infections
 Average of 2 AECBs/year
 Diagnose if patient has 2 or 3 of the
following symptoms:
– Increase in Dyspnea
– Increase in sputum volume
– Purulent sputum
Management of AECB
 Usual
bronchodilator Rx
 Prednisone 25-50 mgm x 7-14 days
 Antibiotics will attenuate the AECB
– Faster resolution of clinical criteria and Peak
Flow Rates, reduced LOS*
– Choice based on antibiotic hx and local
factors
*Anthonisen NR, et al.: Ann Intern Med 1987; 106(2):196-204.
Microbiology of AECB:
Most Common Pathogens by Class

Mild COPD
– H. influenzae, other Haemophilus species,
S. pneumoniae, M. catarrhalis

Moderate COPD with risk factors
– Class I pathogens
– Klebsiella sp.
– Increased likelihood of beta-lactam-resistance

Severe COPD,
– needs hospitalization
– Class I and II pathogens
– Increased risk of P. aeruginosa
AECB: Antibiotic Therapy
 Simple
– COPD mild-moderate; FEV1 >50% pred
– RX: Tetra, Amoxi, Cephalosporin GI or GII, Macrolide
GII or GIII (clarithromycin or telithromycin)
 Complicated
– COPD severe; FEV1 <50% pred
– Any of
» <4 AECB/year, Chronic O2 rx, Recent antibiotics,
CAD, other chronic illness
– RX: Respiratory quinolone, (Gemflox, Levoflox,
Moxiflox)
Acute on chronic
respiratory failure
 Determine
cause
– ?Pneumonia
– ?AECB
– ?CHF
– ?Sedatives
 Assess
with spirometry and ABG
 Oxygenate temperately: avoid greed
 Drugs: as per asthma, plus
Ipatropium (Atrovent)
–Pathogens in CAP
Outpatients
Inpatients
Nursing Home
S. Pneumoniae
H. Influenzae
Atypicals (2)*
S. pneumoniae
H. Influenzae
Atypicals (3)**
GNR
S. pneumoniae
H. Influenzae
Atypicals (3) **
GNR**
* Atypicals (2) = M. pneumoniae, C. pneumoniae
** Atypicals (3) = M. pneumoniae, C. pneumoniae, Legionella spp.
GNR = Gram negative rods
** Negated in EU guidelines
CAP: Selecting Treatment
Type of pneumonia
Modifying factors and/or
pathogens
First-choice therapy
Second-choice
therapy
Outpatient w/out
modifying factors
—
Macrolide
Doxycycline
Outpatient w/
modifying factors
– COPD (no recent anti-biotics
or oral steroids within past 3
months)
– COPD (recent antibiotics or
oral steroids within past
3 months)—H. influenzae &
enteric Gram-negative rods
– Suspected macroaspiration—
oral anaerobes
Macrolides
Doxycycline
Respiratory
fluoroquinolone
Amox/clav + macrolide
or 2nd-gen. cephalosporin + macrolide
Amox/clav +/- macrolide, or 4th-gen.
cephalosporin
3rd-gen cephalosporin +
clindamycin or
metronidazole
S. pneumoniae, enteric Gramnegative rods (?),
H. influenzae
Respiratory
fluoroquinolone alone
or amox/clav +
macrolide
2nd-gen. cephalosporin
+ macrolide
Nursing-home
residents in nursing
home
Mandell LA, et al.: Can J Inf Dis 2000; 11(5):237-47.
Adopted by the CIDS and the CTS
CAP: Selecting Treatment (cont’d)
Type of pneumonia
Modifying factors and/or
pathogens
First-choice therapy
Inpatient ward
—
Resp quinolone
ICU
– Pseudomonas negative
Resp. quinolone
plus
B-lactam/B-l inhibitor
or cefotaxime
Pseudomoonas positive
Cipro plus
antipseudomonal Blactam
Mandell LA, et al.: Can J Inf Dis 2000; 11(5):237-47.
Alternative
–Cephalosporin
+ Macrolide
–Macrolide plus
–ceftriaxone or Blactam/B-l inhibitor
–Antipseudomonal
B-lactam plus
–aminoglycoside plus
–macrolide
Pulmonary Arterial
Hypertension - Classification
 Ideopathic
-includes Collagen
vascular disease, portal
hypertension, HIV, anorexogens
 Secondary
to Pulmonary venous
hypertension - esp CHF
 Hypoxemic
related PAH
 Thrombo-embolic
PAH
Pulmonary Arterial Hypertension:
Diagnosis
 Unexplained
exertional dyspnea
 Isolated impairment of DCO
 Exercise test
 Echocardiogram
 Specialized tests (one or more of):
– Spiral CT
– V/Q scan
– Pulmonary angiogram
Pulmonary Arterial Hypertension:
Therapy of Primary PHtn
 Refer
to specialty clinic
 Oxygen if indicated
 Medications
– …Calcium channel blockers
– Epoprostenol (prostacycline analog)
– Bosentan
(endothelin antagonist)
– Sildenofil
(PDE5 inhibitor)
 Lung
transplantation
Dyspnea management in
palliation:
 Reverse
what can be reversed
 Oxygen for hypoxemia or preemptive
 Opiates – Morphine oral
»15-120 mgm q12h
»s/c route 5-10 mgm q1-6h.
– Dilaudid s/c .5-1.0 mgm q1-6h
Obstructive Sleep Apnea Syndrome
 Heavy
snoring
 Daytime hypersomnolence
 Obesity
 Other manifestations:
– Hypertension
– Unexplained Cor Pulmonale
– Nightmares
– Impotence
– Depression
Obstructive Sleep Apnea Syndrome
Diagnosis:
 Sleep
–
–
–
–
–
–
study or Polysomnography
EEG to stage sleep
Electro-oculography
EKG
Oronasal airflow
Respiratory effort
SpO2
Obstructive Sleep Apnea
Syndrome
 RDI=
Respiratory disturbance index
= # of apneas or hypopneas/hr
Mild OSARDI 5-15
Moderate OSA RDI 16-30
Severe OSA
RDI >30
 Therapy:
– Weight reduction
– CPAP / BiPAP
– Mandibular Prosthesis, Tracheostomy
LMCC topics understressed
 Hemoptysis:
– Refer if major (>200 ml / 24 hours)
– Treat the cause
– Antibiotics
 Pleural
–
–
–
–
effusion
Treat the cause
Drain if pus
Pleurex indwelling catheter if chronic
Pleurodesis if cancer prognosis>3 months and
pleurex support not available