Pulmonary Disease Flashcards
What are some common post op resp complications? How common are they?
- 8% of all surgeries
- atelectasis
- infection (pneumonia, bronchitis)
- bronchospasm
- exacerbation of COPD
- prolonged mechanical ventilation and resp failure (>48hrs)
What is the most common type of pneumonia? what are some findings?
CXR - infiltrate in right middle zone, right heart blurred but preserved right hemidiaphragm
CT chest - alveolar spaces opacified with air bronchograms
tend to see RML pneumonia as aspiration most direct route.
What is the pathophysiology for post op pulmonary complications?
1) Change in physiologic parameters
- vital capacity reduced, FRC and tidal volume reduction
- increased resp rate (?pain)
2) Diaphragmatic dysfunction
- damage to phrenic nerve (thoracic)
3) Pain and splinting
4) Reduced resp drive and drowsiness (opioids/anaesthesia)
5) Cough attenuation
- - retained airway secretions
6) microatelectasis
increased atelectasis
shunting
impaired mucous clearance
pnuemonia
What are some risk factors that contribute to likelihood of post op cx?
Patient factors
- advanced age
- ASA class >2 (ASA 3 or higher)
- COPD (meds)
- active asthma
- smoking
- general health (cog/function)
- CCF (orthopnoea, PND, oedema)
- OSA (snoring, daytime somnalence, STOPBANG)
- pul HTN
Procedure factors
- aortic aneurysm repair
- surg location (incisional site from diaphragm)
- emerg surg
- prolonged surgery (>4hrs)
What does the STOP BANG acronym stand for?
Snoring Tired Observed you stop breathing Pressure - high SBP BMI - >35 Age - >50 Neck size (43cm in males 41cm in females) Gender - male
What are some features on exam you would look for?
- decreased breath sounds
- prolonged expiration
- wheeze
- crackles
- sats <90%
- OSA
- pul HTN (raised JVP, loud P2, peripheral oedema)
What are some investigations you can use pre-op? In what instances would you?
Spirometry
- lung resection, bypass, COPD/asthma, SOBOE/poor tolerance
not recommended routinely
CXR - >50 with thoracic surg
ABG - chronic hypercapneoa in oxygen dependent COPD or advanced restricted lung disease
CPET - lung resection surg
- preop FEV1, DLCO, VO2 max of 15ml/kg/min
- <10ml/kg/min = preop risk
What are the parameters you look at for spirometry?
FEV1/FVC ratio
- <70 = obstructive
- degree of obstruction - % FEV1 pred
- bronchodilator response (>12% or 200mls)
- FEV1 from 1.4L-1.8L
FEV1 <50% mortality of 5.6%
What are some management of COPD principles?
COPD X
- confirm diagnosis (FEV1) with spirometry
- optimise function - pulmonary rehab, physical activity, nutrition, educate, consider co-morbidities (OP, CVD, Lung ca, dep)
- prevent deterioration
- develop support and self management
- manage exacerbations
How do you rank the severity of COPD? When should you add in medications?
% predicted FEV1
mild 60-80%
- short acting relievers (SABA)
- symptom relief (LABA/LAMA)
mod 40-60%
- ICS/LABA combo
- written action plan
severe <40%
- low dose theophylline, oxygen therapy, surgery, palliation
GOLD classification (based on post bronchodilator FEV/FVC ratio)
1 - FEV1 >80%
- influenza, SABA if needed
2 - mod FEV >50% < 80%
- LABA/LAMA
- severe FEV1 <50% but >30%
- inhaled glucocorticosteroids if recurrent exacerbations - very severe FEV1 <30%
- long term O2
- surgical therapies
How do you stratify asthma pre-op and does it alter management?
- stable (similar to non asthmatics)
- asthma meds 30 days prior (postpone non emerg surg)
- consider staroid therapy in poorly controlled asthmatics (40mg once daily for 5 days or 8hrly 100mg IV hydrocort preop if ETT required)
airflow limitation, mucus hypersecretion and airway hyperresponsiveness predispose to complications.
What are the two modifiable risk factors to reduce post op pul complications in thoracic surgery? How do you modify these?
BMI and smoking
Smoking cessation >8 weeks prior to surgery
- NRT
- quit.org.au
What things can you do post op to reduce complications?
- Lung expansion modalities (CPAP, incensitve spirometry, deep breathing exercises)
- Sitting upright
- ANalgesia
- Avoid heavy sedatives
- VTE prophylaxis
- Early physio
Abdo:
- selective NGt decompression
- short acting neuromuscular blockage
What can be used as a predictor of post op pulmonary complications?
ARISCAT Score
- age
- preop spO2
- resp function in last mth
- preop anaemia
- surgical incision
- duration of surgery
- emergency procedure
What is the post op O2 target in COPD patients?
- CO2 retainers the target is reduced as CO2 is their ventilatory drive.
- aim 88-92%
How can you categorise partly vs uncontrolled asthma?
3 or more of the following
- daytime symptoms more than 2x/wk
- limiting activities
- nocturnal symptoms
- needing a reliever >2x/wk
- <80% predicted lung function
- one or more exacerbations a year
What is the stepwise management of asthma?
- inhaled short acting beta 2 agonist (SABA)
- regular preventor (ICS 200-800microg/day
- LABA
- if minimal response to LABA increase ICS if nil response stop LABA and increase ICS
- uptitrate ICS to 2000microg/day
- addition of leukotriene receptor antagonist, SR theophylline, beta 2 agonist
- daily steroid tablet
Which medications should be ceased periop in asthmatics?
Continue all regular medication including inhaled glucocorticoids
Cease theophylline the evening prior to surgery.
What ventilation strategies should be used to reduce the rate of postop complications?
differentiation between normal and injured lung
Intraop
- 6-8ml/kg tidal volume with minimal PEEP
- PEEP reduces atelectasis and maintain O2 in non abdo surgery
- high intraop FiO2 should be avoided to minimise atelectasis.
Postop
- CPAP
- intermittent positive pressure breathing
- suctioning
- chest physical therapy
- deep breathing exercises
- use of HFNO in obese patients
What is the most frequently identified risk factor for postop complications?
COPD
- odds ratio for postop pul cx is higher than other patient factors
A COPD patient in preop clinic produces large amounts of sputum at baseline with unilateral crackles, would you:
a) prescribe Aug DF for 5 days
b) do nothing
c) organise high res CT chest
d) 5 days of pred
e) refer to COPD outreach
c -
chronic suppuration with unilateral crackles may be focal bronchiectasis.
- chest physio and sputum expectoration are vital
In an asthmatic which medication would you not consider prescribing?
a) salmeterol
b) salbutamol
c) budesonide
d) flutucasone/salmetrol
e) budesonide/eformoterol
a) salmeterol
- never give LABA without ICS
asthma is inflammatory and treatment of airway constriction alone for bronchospasm masks the underlying inflammation predisposing to acute/sudden asthma attacks
