LUNG AND ANAESTHESIA Flashcards
How do we diagnose COPD in a patient?
- Strong smoking history
- Chronic cough
- Long expiration >6s
- Wheezing on expiration
- Right heart failure
- Signs of hypercarbia
Can we do elective surgery if there is active bronchospasm?
No
What are the predictors of risk for post-operative pulmonary complications?
- Over 60
- Smoking in the last 6-8 weeks of surgery
- Thoracic or upper abdominal surgery
- BMI of 27
- Abnormal chest X-ray
- PaCO2>6kPa, FEV<1L
What are the types of obstructive lung diseases?
- acute-asthma
- chronic-chronic bronchitis, and emphysema
What is emphysema?
-destruction and dilatation of the air spaces distal To the respiratory bronchioli
What is the main problem in these patients? Inspiration or expiration and why?
- expiration is the main problem
- the more the patients exhales the more the equal pressure point is compressed
How do we make a diagnosis of chronic bronchitis?
-usually diagnosed as a result of sputum production for 3 months a year for 3 years
In regards to chronic bronchitis, what causes the excess sputum?
-the hypertrophy of the mucus producing glands
What is the goal for the pre-op assessment for patients with COPD?
- assess the severity
- develop the anaesthetic plan for the patient
- manage the comobidities
- end organ disease
What do you need to do pre-operatively in patients with COPD?
- History, examination
- side room examination
- special investigations
What questions do you need to ask in history?
- how long they had been smoking for
- whether they are on treatment-inhalers,steroids
- end organ disease(Right heart failure and pulmonary hypertension)
- How well controlled they are-ask them to climb two flights of stairs
What special investigations would you do in these patients?
- Flow volume loop
- ECG
- CHEST X-ray (look for active infection and right heart failure)
- Blood gas test: PaCO2>6kPA
What changes on the ECG would you expect in a patient with right heart failure/cor pulmonale?
- I would expect RBBB
- p pulmonale
- right axis deviation
What do we need the patient to do before the operation?
- stop smoking 4-8 weeks prior to reduce perioperative complications
Stop smoking 24/48 hrs to help with mucociliary clearance - Chest physiotherapy
- Start on antibiotics if active disease
What is important to consider in patients with COPD in regards to premedication?
- It is important to be wary of the use of opiates and benzodiazepines because the. Respiratory depression is more dramatic
- continue chronic medication
- consider additional short acting nebs
What is the first thing you need to do in the first 20-30 minutes before anaesthesia=?
- Give anticholinergic medication intravenously (glycopyrrolate) to block the vagus nerve to prevent bronchoconstriction
Which local block do we need to stay away from in order to prevent possible diaphragmatic paralysis?
-brachial plexus block
What are the effects of anaesthesia on the respiratory function?
- Functional residual capacity decreases which leads to faster desaturation and increased work of breathing
- Atelectasis
- inhibited response to PaCO2, PaO2 and acidosis
Which IV induction agent is best in this case?
-Ketamine or propofol because it has minimal respiratory suppression
Which inhalational drugs would you use in COPD?
- sevoflurane
- isoflurane
- halothane and avoid desflurane
What ventilator settings do you need to place for this patient?
-expiratory time on the ventilator must be prolonged
-larger tidal volume
-reduce the number of breaths per time unit
-
What do we need to do post-operatively?
- supplemental oxygen or CPAP
- physiotherapy
- analgesia
- early moboilisation
What drug is glycopyrrolate?
-anticholinergic and is used pre-op in COPD patients to prevent bronchospasm
