6.4 COPD Flashcards
You take a telephone call from a concerned nurse regarding a 70-year-old female patient with COPD being admitted on the surgical ward.
The patient has a productive cough, respiratory rate of 32/min, and sats 88%
(on oxygen).
The patient is awaiting an incisional hernia repair.
can you define COPD?
Chronic lung disease characterised
by airflow limitation due to progressive inflammatory disease,
which is not fully reversible,
often complicated by significant
systemic manifestations and comorbidities.
Classic symptoms COPD
- productive cough,
- dyspnoea,
- wheeze,
- frequent winter bronchitis,
- exercise intolerance.
The pathogenesis of COPD
The pathogenesis of COPD is
thought to arise from the combined effects of
inflammation,
increased oxidative stress,
an imbalance between proteinases and anti-proteinases.
Historically there are two types:
emphysema and chronic bronchitis.
Pathologic changes of COPD
Pathologic changes of COPD
are present throughout the lung.
- Large central airways:
enlarged mucous glands,
loss of cilia,
decreased ciliary function,
increased smooth muscle
connective tissue deposition in the airway walls - Small airways:
collagen deposition
airway remodeling
How do you diagnose COPD?
Spirometry is used to confirm the diagnosis
classify the severity of COPD
but will be more robust
when complemented with clinical status
and radiology investigations.
Both the NICE and the GOLD offer guidelines
for the diagnosis and assessment of CoPD.
- Airflow obstruction
- Airflow obstruction
Defined by a ratio of forced expired volume in one second
to forced vital capacity (FEV1/FVC) < 0.7
is used to diagnose COPD.
° If FEV1 is > 80% of the predicted value,
then COPD is diagnosed only in presence
of respiratory symptoms.
° Reversibility testing with corticosteroids or bronchodilators is
unnecessary for the diagnosis but they are used to differentiate CoPD
from asthma.
Classification based on FEV1% pred
FEV1% predicted GOLD criteria (2008) NICE (2010)
- < 80% Mild Stage 1—mild
- 50%–79% Moderate Stage 2—moderate
- 30%–49% Severe Stage 3—severe
- < 30% Very severe Stage 4—very severe
What are the complications in untreated COPD patients?
- Expiratory airflow limitation arises
due to airway inflammation and
hyperplasia,
mucus accumulation,
fibrosis,
bronchospasm. - Expiratory flow is decreased and expiratory time prolonged
with resultant hyperinflation,
which increases total lung capacity,
functional residual
capacity, and residual volume,
giving rise to exertional dyspnoea.
- V/Q mismatch due to increase in physiologic dead space and shunt.
- Chronic hypoxia leads to
secondary polycythemia,
pulmonary hypertension,
eventually right ventricular dysfunction
cor pulmonale.
How do you manage COPD?
Preventive
- Smoking cessation is the only intervention that slows the progression.
- Yearly influenza vaccination has been shown to significantly reduce
morbidity and mortality and is recommended for all patients with COPD.
How do you manage COPD?
Pharm
Pharmacologic management
* Early-stage COPD: Short-acting inhaled bronchodilators
.
* Severe COPD:
° Long-acting inhaled bronchodilators (tiotropium)
improve lung function
and relieve dyspnoea.
° Inhaled corticosteroids
decrease frequency of exacerbations and slow
the rate of decline in FEV1.
° Combination therapy seems to show additive benefits.
Treatment of acute exacerbations:
- Oxygen
* Domiciliary oxygen therapy for patients with hypoxia - Drugs
* Appropriate antibiotics if suspected infection
* Escalate bronchodilator therapy
* Systemic corticosteroids to shorten the recovery time - Ventilation
* Progressive hypercarbia and respiratory acidosis
warrant noninvasive mechanical ventilation
to avoid the need for intubation.
- Patients with severe acidosis,
refractory hypoxemia, or
respiratory arrest require intubation
and mechanical ventilation.
Treatment of end-stage disease
Treatment options for advanced CoPD are limited.
* Domiciliary oxygen therapy. Aim for sats > 90%
- Lung volume reduction surgery—
high-risk palliative treatment, which is
performed especially for upper-lobe emphysema - Lung transplantation
How will you manage this patient?
Patients with CoPD have a two- to five-fold increase in risk of perioperative
pulmonary complications such as atelectasis, pneumonia, and respiratory
failure.
Preoperative management
- ABCD approach; optimise oxygen and drug therapy.
- Risk assessment—patient and surgical factors.
- Investigations—
besides routine investigations,
a bedside spirometry and a chest radiograph is
obtained to influence clinical management.
Consider echocardiography if ECG reveals right heart disease
(right ventricular hypertrophy or strain).
A baseline ABG on room air with
PaCo2 > 5.9 kPa
Pao2 < 7.9 kPa
predict a worse outcome.
- Advice smoking cessation.
- Appropriate antibiotics for suspected bacterial infection,
systemic corticosteroid,
escalate bronchodilator therapy.
- Appropriate antibiotics for suspected bacterial infection,
If permissible, delay surgery until after full recovery
from an acute CoPD exacerbation.
Intraoperative management
- Where possible,
neuraxial analgesia and peripheral nerve blockade for
postoperative pain relief are offered.
- Where possible,
- Airway manipulation can worsen the condition
and may be treated with short-acting bronchodilators
such as β2 agonists or anticholinergics.
- Airway manipulation can worsen the condition
Bronchodilating volatile anaesthetics
(isoflurane, sevoflurane, halothane, enflurane)
also may reverse acute bronchospasm.
- Titrated dose of neuromuscular blockers is crucial
as is adequate reversal at the end of operation.
- Titrated dose of neuromuscular blockers is crucial
- Ventilation strategy:
Avoidance of dynamic hyperinflation
by the use of a slow respiratory rate,
long expiratory time,
minimal tidal volume to avoid excessive hypercapnia.
- Ventilation strategy:
Use extrinsic PEEP judiciously to replace intrinsic PEEP.
- Fluid balance is crucial in patients with cor pulmonale
where appropriate right ventricular preload is
essential to produce adequate cardiac output
when the right ventricular afterload is high.
- Fluid balance is crucial in patients with cor pulmonale
