18/Oct/2005Dr. David P. Breen1 COPD- Burden of Disease Initial management of an acute exacerbation.

18/Oct/2005 Dr. David P. Breen 1

COPD- Burden of Disease

Initial management of an acute exacerbation


DefinitionCOPD is a disease state characterized by

airflow limitation that is not fully reversible. The airflow limitation is usually both progressive and associated with an abnormal inflammatory response of the lungs to noxious particles or gases.

Symptoms, functional abnormalities, andcomplications of COPD can all be explained on the basison this underlying inflammation and the resulting pathology

www.goldcopd.com


Lung Function decline


Spirometry is the GOLD Standard for the diagnosis of COPD


Exacerbations of COPD

Acute exacerbations of COPD present as a worsening of a previously stable conditionImportant symptoms include

Increased sputum purulenceIncreased sputum volumeIncreased dyspnoeaIncreased wheezeChest tightnessFluid retention


Exacerbation

A new respiratory event or complication superimposed upon established diseaseNew events

PneumoniaPneumothoraxLVF/ Pulmonary OedemaLung CancerUpper airway Obstruction


Acute exacerbation of COPD1. Airflow Obstruction

a) Dyspnoeab) Wheezec) Chest tightness

2. Respiratory Failurea) Hypoxia

i. Dyspnoea, tachypnoea, cyanosis, confusion

b) Hypercapniai. Warm hands, dilated veins, tachycardia, bounding pulse, flapping

tremor, chemosis, papilloedema, confusion, agitation

3. Cor pulmonalea) Loud P2, RV (L Parasternal Heave), raised JVP, peripheral oedema

4. Infectiona) Increased sputum volume/purulence, fever, raised WCC


Investigations

Full Blood CountRenal ProfileArterial Blood GasChest X-Ray

PneumoniaBronchiectasisPneumothoraxLVF

Spirometry prior to discharge


TREATMENT

Airflow Obstruction Bronchodilators- Salbutamol, ipratropium Corticosteroids

Respiratory Failure See later

Cor Pulmonale Daily weight, accurate input/output chart Diuretics Monitor renal function carefully

Infection Antibiotics physiotherapy


Acute Respiratory Failure

ABG Normal PO2 10.5-12.5 KPa

Normal PCO2 4.5- 6.0 KPa

Type 1 Failure PO2 PCO2 N or

Type 2 Failure PO2 PCO2


Normally we breath mainly in response to raised PCO2 In Type 1 failure, this response is maintained

High O2 is safeIn COPD, there is usually chronic CO2

retentionThe brain gets tired of responding to the raised PCO2

The main stimulus to breathe is then a decreased PO2


So, How much O2 should we give?

Oxyhaemoglobin dissociation curve

0

20

40

60

80

100

1 2 3 4

PO2 (KPa) Arterial Blood Gas

O2

del

iver

y to

tis

sues

H

b s

atu

rati

on

(%

)


In Type 2 Respiratory Failure

PO2 Hypoxic Drive SaO2 O2 Delivery

7.5 maintained 90% adequate/good

<7 maintained <90% poor

5.0 maintained <70% dangerously low

7.5 maintained 90% adequate/good

>8 decreasing >90% good

10 very poor 95% good


ThereforeLook first at PO2

Maintain PO2 around 7.5-8.0 (SaO2 90-92%)

Do not be afraid to give enough O2 to achieve this

Do not push PO2 above this – very little extra delivery of O2 to all tissues and loss of hypoxic drive now becomes a problem

Monitor PCO2 and clinical conditionIf PCO2 elevated or clinical condition poorConsider N.I.VStart with 24-28% and titrate upwardsMonitor Sats and ABG


But remember :

Cigarettes are the main culprit!!


Non-Invasive Ventilation:


Selection Criteria

Respiratory distressModerate to severe dyspnoeaAccessory muscle useParadoxical movement of abdominal

musclespH<7.35 with PaCO2>6kPaRespiratory rate >25breaths/min

At least two criteria should be present


Exclusion Criteria (Absolute)

Respiratory Arrest situationCardiorespiratory instability

HypotensionArrhythmiaMyocardial infarction

Uncooperative patientRecent facial, oesophageal or gastric

surgery


Exclusion Criteria (Absolute)

Craniofacial trauma or burnsHigh aspiration risk

Absent gag reflexInability to manage secretions

Fixed anatomical abnormalities of the nasopharynx


Relative Contraindications

Extreme anxietyMassive obesityCopious secretionsAdult Respiratory distress

syndrome-ARDS

American Respiratory Care Foundation.


Complications

Local damage related to mask/strap pressureGastric distensionEye irritationSinus painNasal congestionBarotraumaAir leaksAdverse Haemodynamic effects rareNosocomial pneumonia rare


Predicting Poor Outcome

Higher APACHE II score (15 Vs 20)Acute physiological and chronic health

evaluationLower pH in those who failed

7.22 Vs 7.28 Ambrosino et alLower FVC Presence of pneumonia

Soo Hoo et al Crit Care Med 1994


Suggested settingsNIPPY

Aim for IPAP of 20Normal breathing= 1sec insp, 2sec exp,will

probably need to be shortenedSet trigger low eg. 0.5 = less effort required by

patientBIPAP

Suggest starting with IPAP 10 or 12May increase to 20 or higherSuggest starting with EPAP of 4Never use less than EPAP of 4 = CO2

rebreathingMay increase EPAP to 6, seldom require higher


Effectiveness

Significant decrease in mortality (9% Vs 29%) Brochard et al NEJM 1995


Effectiveness

Significant decrease in ICU length of stay (13 Vs 32 days) Wysocki et al Chest 1995

Significant decrease in hospital length of stay (23 Vs 35 days) Brochard et al NEJM 1995

18/Oct/2005Dr. David P. Breen1 COPD- Burden of Disease Initial management of an acute exacerbation.

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