Preop Assessment Flashcards
Bruce Protocol
- Seven stages of 3 mins, but normally do around 12 mins.
- Ideally should reach 85% of max HR (220-age for men, 210- age for F).
- Stage 1: 1.7mph up 10% incline (4.8 METs).
- Look for abnormal ST response (horizontal or down-sloping ST depression >1mm)
- Not to be done if MI in last 6 days, unstable angina in last 48 hours, CCF, myocarditis/pericarditis, DVT, sysBP>220 or DBP>110, severe AS or HOCM.
Predisposing conditions for obstructive sleep apnoea
Obesity Age 40–70 yr Male gender Excess alcohol intake Smoking Pregnancy Low physical activity Unemployment Neck circumference >40 cm Surgical patient Tonsillar and adenoidal hypertrophy Craniofacial abnormalities (e.g. Pierre Robin, Down's syndrome) Neuromuscular disease
STOP-BANG questionnaire questions
≥3 questions=high risk of OSA.
<3 questions=low risk of OSA
STOP
S (snore) Loud snoring
T (tired) Daytime tiredness
O (observed) observed cessation of breathing during sleep
P (blood pressure) Have or being treated for high blood pressure
BANG B (body mass index) BMI >35 kg m−2 A (age) Age >50 yr N (neck) Neck circumference >40 cm G (gender) Male
Objective investigation of OSA.
What is PSG?
polysomnography (PSG) will establish the extent and severity of OSA.
PSG examinations include:
- heart rhythm (ECG),
- electroencephalography (EEG),
- eye movements
- electromyography.
OSA.
What is AHI?
The apnoea/hypopnoea index (AHI) is calculated from the number of apnoea and hypopnoea periods lasting 10 s or longer per hour of sleep.
Objective criteria for diagnosis of OSA
The severity of OSA is categorized from an AHI of ≥5, ≥15, and ≥30 designating mild, moderate, and severe OSA, respectively.
In settings without access to PSG, OSA may be assessed by the number of peripheral oxyhaemoglobin desaturations >4% h−1 (oxygen desaturation index, ODI).
An ODI of ≥5 is considered significant.
