Anaesthesia for Thoracic Surgery Flashcards
what is the main anaesthetic consideration when opening the thorax?
ventilation
why is ventilation a concern when opening the thorax?
opening the thorax removes negative pressure in the pleural space
what is the impact of the removal of negative pressure through opening the thorax?
when the chest wall expands on inhalation there is little or no air entry into the lungs as the pressure in the lungs is the same as atmospheric pressure
ventilation is inadequate and gas exchange impaired
what is needed during thoracic surgery to ensure adequate ventilation?
manual or automatic IPPV throughout surgery
what is caused by opening the thoracic cavity?
atelectasis
what is decreased by atelectasis?
total lung capacity
vital capacity
functional residual capacity
what is commonly seen during thoracic surgery even with IPPV?
atelectasis
what can worsen atelectasis during thoracic surgery?
packing off lung lobes
manipulation of blood vessels altering supply
leak testing
pathology patient was admitted with
what is functional residual lung capacity?
gas left in the lungs after expiration
what is the role of functional residual capacity?
reserve gas exchange occurs between breaths
which surgical approach to the thorax is more painful?
sternotomy - more retraction required and more muscle damage than thoracotomy
what thoracic surgical approach is least painful?
thoracoscopy
what must be considered when patients are undergoing thoracoscopy?
large volume of CO2 insufflation
lungs can become compressed
when may ventilation be required from the start of abdominal surgery?
diaphragmatic hernia repair
why is thoracotomy so painful?
skin incision
nerve damage
retraction of ribs to allow access leading to muscle damage
inflammation at surgical site
what can be caused by poor analgesia during thoracic surgery?
hyperalgesia
what is the impact on patient ventilation following thoracic surgery?
ventilation less effective as lung inflation is compromised due to pain making patient unwilling to move their chest
what are the main reasons for thoracic surgery?
respiratory system
cardiovascular
oesophageal FB
thoracic duct ligation
what are the main respiratory system reasons for opening the thorax?
lung lobe torsion
bulla
neoplasia
abscess
what are the main considerations for thoracic surgery involving the respiratory system?
pre existing pneumothorax
hypoventilation
hypoxaemia
pre-disposed to decompensation
pathology already compromising respiration
what are the main cardiovascular system reasons for opening the thorax?
patent ductus arteriosus
persistent right aortic arch
pericardectomy
heart surgery
what are the main considerations for thoracic surgery involving the cardiovascular system?
CVS changes due to primary lesion or surgical manipulation
bleeding
hypotension
risk of arrhythmias
what are the main considerations for persistent right aortic arch?
paediatric
present with regurgitation
risk of aspiration
may be malnourished
what should you be aware of during PDA closure?
may be significant changes
bradycardia and hypertension
what are the main considerations for opening the thorax for non-respiratory/CVS reasons?
contamination risk
infection
pain
risk of aspiration
risk of regurgitation
sepsis
what is vital for thoracic surgery?
preparation
what is involved in preparation for thoracic surgery?
blood type
check blood availability
hypotension treatment plan (drugs/fluids)
pre oxygenation
check ventilator or IPPV facilities
ensure monitoring equipment ready
analgesia plan
what must happen before thoracic surgery?
patient is as stable as possible
how may patients be stabilised for thoracic surgery?
chest drainage
pre-oxygenation
fluids
what must be considered about pre-oxygenation?
must not cause further stress as may worsen respiratory function
method should be best available for patient
what is the aim with all anaesthetic drugs for thoracic surgery?
minimal CVS depression
analgesia
what drug type might be avoided in thoracic surgery patients?
alpha-2 agonists
ACP
what drugs may likely be needed during thoracic surgery?
inotropes (e.g. noradrenaline)
additional analgesia infusions (e.g. fentanyl)
what is etomidate used for?
induction
CRI
is etomidate licensed for animals in the UK?
no
what type of drug is etomidate?
IV
ultra short acting
nonbarbituate
what are the advantages of etomidate?
minimal CVS depression
what are the disadvantages of etomidate?
poor quality of induction unless premed is very good or the animal is very sick
what is the main benefit of fentanyl during anaesthesia?
MAC sparing
what is the benefit of giving MAC sparing drugs such as fentanyl during anaesthesia?
reduce CVS/respiratory system depression seen with volatile anaesthetic agents as the level can be reduced
what is the speed of onset of action of fentanyl?
within 5 minutes