Exacerbation of COPD/CO2 narcosis

Question 1

A 60 year old man is admitted to hospital with an acute exacerbation with COPD. Within hours of his admission, the nursing staff report that he has become drowsy and difficult to rouse. How would you assess and manage him?

Imp/DDx/Goals

Answer 1

Impression
This patient has an altered mental state/obtunded in the context of exacerbation of COPD and likely CO2 retention and narcosis. This may be related to over-zealous 02 therapy [removing hypoxic drive for respiration]. Concerned about respiratory arrest and respiratory acidosis. Would want to rule out life-threatening causes of this presentation including stroke, ACS, and PE.

DDx

• ACS, PE
• Delirium (hypoactive)
• medications
• intercurrent infections
• hypoglycaemia, other electrolyte derangement.

Goals

• Thorough H/E/I to identify underlying aetiology of mans altered mental state, start with ABCDE resuscitative approach and urgent VBG, reduce Fi02 therapy and aim sats of 88-92.
• Institute appropriate emergent and ongoing management to prevent complications

Question 2

CO2 narcosis - Assessment

Answer 2

Assessment
A - patent, maintaining own. adjuncts as required
B - RR, sats, supplemental 02. aim for sats of 88-92 if chronic CO2 retainer. check patient notes for past history of COPD, previous treatments. Consider invasive ventilation if not adequately saturating (escalate care to ICU). Provide therapy for COPD exacerbation; SABA and SAMA +/- systemic corticosteroids
C - 2xIVC, bloods (VBG is urgent), BP monitoring. Blood pressure support as required. Serial ECG. ABG (PaC02 > 45 mmHg, pH, HCO3, etc). RSI if intubating emergently
- correct electrolyte derangements
D - GCS
E - Secondary survey
F - Fluid status

Question 3

C02 Narcosis - History

Answer 3

History

• sx: SOBOE, exercise tolerance, recent illnesses, productive cough, WOB, use of medications, timeline of presentation
• REDF: weight loss, night sweats, fevers, palpitations, chest pain
• HxPC: previous exacerbations
• PMHx: cardiac disease, renal disease
• Medications
• SNAP

Question 4

C02 Narcosis - Examination

Answer 4

Examination:

• General obs + vitals
• Cardiorespiratory examination: distress, cyanosis, peripheral warmth/erythema (C02 is vasodilator), hypotension.

Question 5

C02 Narcosis - Investigations

Answer 5

Investigations

• as per ABCDE assessment
• Imaging: CXR at patient bedside (rule out complications/ddx)

Question 6

C02 Narcosis - Management

Answer 6

Management
Definitive
- resus as described in A to E assessment
- ICU referral/retrieval as necessary
- then depends on underlying aetiology: COPD = antibiotics, + ongoing long-term mx,

Supportive

• ensure sats maintained at 88-92 if a C02 retainer
• regular obs and medical review

Ongoing

• ?home 02
• prophylactic ABx for future exacerbations
• allied health input and rehabilitation