Week 7 Flashcards
What are PPC’s?
Post operative pulmonary complications that increase morbidity, mortality and length of stay in hospital
What general effects can surgery have on respiratory function?
decreased lung volumes (due to atelectasis, hypoxemia, drop in FRC and VC from positioning and immobility)
decreased mucociliary function (due to anaesthetic use, mechanical ventilation & pain medication)
decreased diapragm excursion (due to paralysis effect of anaesthetics & supine positioning not allowing good movement of the diaphragm)
What defines that a patient has PPC’s?
patient will usually have 4 or more of the signs & symptoms described by the Melbourne Group Scale
What are the 8 signs & symptoms of PPC’s according to the Melbourne Group Scale?
- CXR atelectasis/consolidation
- temp >38 after day 1
- raised white blood cell count or prescription of antibiotics specific for lung infection
- SPO2 <90% ORA
- new production of yellow/green sputum
- positive signs of infection on sputum microbiology
- diagnosis of pneumonia
- readmission to or prolonged stay >36 hours in ICU
Describe the pathophysiology of microatelectasis following surgery.
Small areas of collapse within the lungs due to insufficient ventilation & reduced surfactant production (due to anaesthesia, drying O2 use, mechanical ventilation, infection)
this can also be due to absorption atelectasis following surgery which is when a bronchus or bronchiole is blocked and not allowing ventilation to sections of alveoli
What are Allie’s S’s that increase the risk of atelectasis post surgery?
surgery
sore/pain
shallow breathing
supine/slumped position
increased secretions
decreased surfactant
senior/advanced age
supplemental O2
synthetic/mechanical ventilation
no sighs (to reinflate airways)
smoking history
size (obesity)
Describe the factors that reduce mucociliary clearance post surgery.
decreased cilial beating (due to drying out with O2, dehydration, endotracheal intubation, retained secretions/poor cough effectiveness)
increased secretions (due to underlying lung disease i.e. CF, infection, dehydration)
What are some patient-related risk factors for PPC’s?
advanced age
impaired functional status
respiratory & cardiac disease
smoking history
reduce serum albumin levels
sleep apnoea
ASA comorbidity scale class 3-5
cancer (healing capacity)
malnutrition
immunocompromised
impaired cognitive function (unable to follow post op instruction)
What are some procedure-related risk factors for PPC’s?
anaesthesia >180 minutes
type of surgery i.e. upper abdominal, thoracic, neuro, head & neck, vascular, aortic aneurysm repair
emergency vs elective surgery (no pre-hab)
Why is advanced age risk factor for PPC’s?
higher closing capacity and reduced FRC already
decreased elastic recoil of the lungs
generally weaker respiratory muscles
Describe the ASA comorbidity scale.
A scale used to classify patients by comorbidities to predict those at higher risk of developing PPC’s.
ASA classification of 3-5 includes what kinds of patients?
those with systemic disease that is severe to life threatening
What are the adverse effects of general anaesthesia on the respiratory system?
drying of cilia
secretion retention
loss of cough reflex
reduced FRC
respiratory inhibition
atelectasis
decreased alveolar ventilation
What are the adverse effects of post surgical pain on the respiratory system?
poor cough
impaired ability to breath deeply & sigh
can lead to respiratory distress
What are the adverse effects of pain medications?
respiratory depression
postural hypotension
nausea, vomiting
drowsiness
paralytic ileus
urinary retention
