Flashcards in ILA 7: Resp disease & anaesthesia Deck (13)
Mr. Jones is a 60 year old retired cab driver who has come in for a revision knee replacement. He is seen regularly in chest clinic with COPD. His BMI is 31.5.
- How will you assess Mr Jones respiratory status?
- Acute symptoms: current infection, SOB, reduced exercise tolerance, etc.
- Long-term disease control: medications, admissions (esp. HDU/ITU), oral steroid courses, HMV/LTOT
- Resp exam (paraphernalia, clubbing, hypoxia, accessory muscles, talk fluently, focal signs)
- FEV1 (<0.3 = very severe, 0.3-0.5 = severe, 0.5-0.8 = moderate, >0.8 = mild)
- FEV1/FVC ratio (<0.7 = COPD)
- Blood gas (well-compensated?)
- Possible CXR if focal signs suspected
Pathophysiology of COPD
Inflammation of the airways, causing thickening of the epithelium and mucus production, resulting in airways obstruction (irreversible).
Leads to air-trapping and emphysema.
- Medications: SABA, LABA, ICS, etc.
Breathlessness: MRC classification
(note: NYHA is used for cardiac disease)
1 - not troubled by SOB except on strenuous exercise
2 - SOB when hurrying on level ground or walking up slight hill
3 - walks slower than normal people or stops after 15 mins walking at own pace
4 - stop after a few hundred yards/few mins on the flat
5 - too breathless to leave house/breathless on undressing
How can cardiorespiratory function be measured?
How can functional status be measured?
How can you prepare this COPD man for surgery?
- Stop smoking ideally 6-8 weeks pre-surgery (and at least 12 hours before)
- Optimise medications to alleviate symptoms
- Weight loss
- Physiotherapy - increase exercise tolerance
Mr Jones’ wife comments in pre-assessment clinic that he snores loudly. What relevance might this have? What further questions would you like to ask Mr Jones and his wife? How may you take this further?
- May indicate airway obstruction
- Upon extubation, airway may obstruct due to anaesthetic effects
- Opiates may worsen this
OSA: risk factors
Mnemonic - STOP BANG
(0-2: low risk of OSA, 3-4: moderate, 5-8: high risk)
Tiredness during the day
Neck circumference >40cm
OSA: operative management
Pre-op: blood gas, book HDU bed post-op
Op: avoid GA and sedation if possible, if need GA then use ETT.
Post-op: extubate carefully, HDU
Why spinal may be preferable to GA
- You shouldn't put someone under GA (if can be avoided) where they are at risk of difficult extubation
- Less post-op issues: when spinal wears off, they will probably be okay to go home
- BP lower: less blood loss
- Improved venous circulation: lower VTE risk
Oral steroids can cause adrenal suppression and subsequent inadequate response during stress, such as the peri-operative period.
What should you do about this?
Convert oral steroids (pred) to IV hydrocortisone. Conversion ratio = 1:4 (10mg pred = 40mg hydrocortisone)