Anaesthesia for Airway/Dental/Ocular Surgery Flashcards
What general considerations can we have for dental anaesthesia?
Restricted access to head
Lots of water - cold/aspiration
Geriatric patients/underlying conditions
Painful!
What anaesthetic considerations should we have for dental surgery?
Pain
Haemorrhage
Hypothermia
Aspiration of water/fluids
Length of procedure
Concurrent disease
What anaesthetic considerations should we have for geriatric dental patients?
Reduced CV reserve - baroreceptor function reduced = more prone to hypotension
Reduced functional residual capacity (FRC) - more prone to hypoxia
Reduced muscle mass - prone to hypothermia
Reduced liver/kidney function - drug dosages, length of action
What pre-op considerations should we have for dental patients?
Blood/urine testing
Other diagnostics e.g. X-rays?
Full clinical exam - anorexia? common in cats with dental dx
Other disease processes?
Fluid therapy - pre/peri/post?
Premedication - may already be on abx/NSAIDs
Breathing system selection
What analgesia can we consider for dental surgery and why?
Consider local blocks
Analgesia is vital! - MAC sparing properties
What peri-op considerations should we have for dental patients?
Cuffed ET tube essential
Risk of aspiration due to water from machine - mouth pack must be in place
Care when turning - ensure ET tube not kinking/twisting
Avoid spring-loaded mouth gags esp. in cats
Haemorrhage risk
Positioning - pad joints/consider atelectasis
What does an infraorbital (rostral maxillary) nerve block numb?
Soft tissues, incisor/canine and premolar teeth
Where do we carry out an infraorbital (rostral maxillary) nerve block?
In dogs - located on maxilla, dorsal to third maxillary premolar
Care in cats and small/brachy dogs - foramen is at the level of the medial canthus of the eye
What does a caudal maxillary nerve block numb?
All bones of maxilla
Soft and hard palates
Soft tissues of nose and upper lip
Dentition rostral to maxillary second molar
Where do we carry out a caudal maxillary nerve block?
Just caudal and central to last maxillary molar
What does a mandibular nerve block numb?
Entire hemimandible teeth of lower jaw (therefore bilateral discouraged due to risk of damage in recovery)
Where do we carry out a mandibular nerve block?
Percutaneously at ventral angle of mandible
What does a mental nerve block numb?
Lower incisors, skin and tissues rostral to foramen
Where do we carry out a mental nerve block?
Ventral to rostral root of second premolars
Easily palpated in large animals but tough to locate in smaller animals
What equipment is required for local nerve block placement?
Sterile needle and syringe
Local agent (lidocaine/bupivacaine - factor in use of Intubeaze in cats!)
Scrub
Alcohol wipe/liquid
Sterile gloves
Record of doses/times
What post-op considerations should we have for dental patients?
Analgesia!
Keep warm, dry off as much as possible
Remove mouth pack!
Tempt to eat
Continue fluids if needed
Discharge for owners - expect some bleeding etc.
What pre-op considerations should we have for ocular surgery patients?
Pain?
Possibility of rupture?
Concurrent diseases?
Procedure being performed?
Premedication drugs
Clip and prep - iodine solution
What peri-op considerations should we have for ocular surgery?
General anaesthetic considerations
Prevent further trauma e.g. Bair huggers
Maintenance of central eye for intraocular procedures
Analgesia
Manage intraocular pressure
Oculo-cardiac reflex
What is normal IOP?
15-20mmHg
How can we manage IOP?
Avoid acute increases e.g. coughing, straining, vomiting
Avoid drugs that may emetic effects e.g. morphine
Maintain a normal CO2
Avoid neck restraint/jugular pressure
Positioning - avoid ‘head down’ position
Describe the oculo-cardiac reflex.
Sudden reduction in heart rate associated with traction on the eye or surrounding structures
Due to stimulation of trigeminal and vagal nerves
How can we maintain a central eye for intraocular surgery?
Most common technique is to use neuromuscular blocking agents
Describe analgesia regimes for ocular patients.
Pre-emptive and multi-modal
Vital to prevent self-mutilation
Opioids, NSAIDs, topical local drops etc.
Retrobulbar block
What does a retrobulbar block numb?
Cranial nerves II, III, IV, V (ophthalmic and maxillary branches) and VI
What post-op considerations should we have for ocular patients?
Analgesia
Buster collar
IVFT if needed
Continue medication e.g. topical
Feed, opportunities to toilet
Prevent coughing/vomiting esp. if IOP increased
Consider re-sedation/top-up if anxious/fractious
What airway surgeries can be undergone?
Treatment of airway condition e.g. BOAS laryngeal paralysis
Investigative bronchoscopy e.g. chronic cough, tracheal FB
Tracheal stenting
What are the primary abnormalities associated with BOAS?
Stenotic nares
Aberrant nasal turbinates
Elongated/thickened soft palate
Tracheal hypoplasia
How do BOAS patients compensate for their primary abnormalities?
Pulling harder of inspiration
Creates negative pressure in throat, neck and chest
What secondary abnormalities can BOAS patients get?
Laryngeal collapse
Eversion of laryngeal saccules
GI - reflex/regurgitation
What pre-op considerations should we have for BOAS patients?
IV access vital - rapid induction and intubation
Prevent stress
Observation! - sedated patients can easily obstruct and regurgitate
Control temperature - consider naturally hyperthermic
How can we protect the airways of BOAS patients during anaesthesia?
Pre-oxygenation
Intubation stylet?
Range of ET tube sizes
Cuff!
Risk of regurg and aspiration - suction available, head down until airway secured
What peri-op considerations should we have for BOAS patients?
Airway management - may need ventilation support
Careful monitoring - ETCO2, BP, SpO2, ECG
Maintain heat but avoid overheating
Eye care crucial
What post-op considerations should we have for BOAS patients?
Observation is key!
Do not remove ET tube until actively swallowing and can maintain patent airway
Be prepared for re-intubation
Mild sedation can be useful in recovery for agitated patients
Care with warming
Oxygen supplementation, pulse ox.
Discharge ASAP
How can we manage post-op respiratory distress in brachycephalics?
Adrenaline in a nebuliser
Careful with NSAID use pre-/peri-op - steroids may be needed post-op for resp crisis
What are the typical clinical signs of laryngeal paralysis?
Stridor (high-pitched breathing sounds)
Exercise intolerance
Panting
Coughing
Hoarse bark
How can nurses initially manage a dog presenting with suspected laryngeal paralysis?
Quiet/stress-free environment
No stress - do not immediately place IVs etc.
Use a fan to cool and blow air into airways
Oxygen supplementation if not increasing stress
Start hosp records and monitor RR
Speak to vet (butorphanol?)
Leave alone until calm and observe from a distance!
What is the name of laryngeal paralysis surgery?
Unilateral Arytenoid Lateralisation (UAL) ‘tie-back’
What pre-op considerations should we have for laryngeal paralysis patients?
Risk of regurg/aspiration
Pre-oxygenate, reduce stress
Surgeon will want to assess laryngeal function under light plane of anaesthesia prior to intubation - consider pre-med/induction doses
Pain management!
What post-op considerations should we have for laryngeal paralysis?
Close observation
Anti-tussive drugs
Aspiration pneumonia a huge risk in recovery period
Pain assessment
Avoid collars etc. - use harnesses
Feed from height with balls of wet food
Avoid excitement/consider sedation
What clinical signs/diseases may indicate a need for bronchoscopy?
Variable presentation
Chronic cough
Suspected lung infection
Feline asthma
Airway parasites
Chronic aspiration pneumonia
Neoplasia
What bronchodilators can be given to a dyspnoeic patient prior to bronchoscopy?
Terbutaline - but be aware of CVS effects e.g. tachycardia
Why would we want to perform a bronchoscopy?
For the collection of samples (Bronchial Alveolar Lavage BAL)
What pre-op stabilisation can we offer to bronchoscopy patients?
O2 and sedation if needed
Inhalational bronchodilators
Systemic steroids and anti-tussive medication
What peri-op considerations should we have for bronchoscopy patients?
May not be able to keep ET tube in place - consider TIVA and flow-by oxygen
Airway protection crucial
Animal can get cold due to use of coupage etc.
What pre-op considerations should we have for bronchoscopy patients?
Minimal stress
Propofol and ketamine have bronchodilatory effects
Appropriate depth for induction
Large diameter ET tube - scope might be able to pass through, otherwise will need to be removed
Use of pulse ox./Doppler can be useful
What potential peri-op complications can occur during bronchoscopy?
Hypoxia
Bronchoconstriction (after BALs)
Desaturation and shark-fin capnograph
Reduced compliance
Laryngeal oedema - cats
Airway/lung rupture - possible during FB removal or biopsy
What equipment do we need for bronchoscopy?
Endoscope (take pre sample!)
Sterile saline
Collection pots
Mouth gag?
Urinary catheter (for flow-by oxygen)
Syringes
Crash box/induction agent
3 people minimum!
What post-op considerations should we have for bronchoscopy patients?
May have a cough
Can easily occlude airway e.g. by low head carriage
Constant monitoring until walking!
Keep head elevated and use towels to prevent occlusion
Monitor SpO2 - provide oxygen supplementation as tolerated
Pneumothorax can manifest clinically later in recovery period
What post-op complications can occur for bronchoscopy patients?
Haemorrhage in airways
Desaturation of oxygen
Pneumothorax due to damaged bronchi
May be tension pneumothorax
When might we consider pharyngostomy intubation?
To avoid oral cavity
Or where orotracheal intubation is not possible
