11513522
Description
Flashcards by Rachael Jones, updated more than 1 year ago
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Created by Rachael Jones
over 6 years ago
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| Question | Answer |
| What is the preparation required for anaesthesia? | - Induction (and recovery) are risky phases - Stressful - Preparation - Anticipation - Team approach |
| How is induction of anaesthesia achieved? | Administering a drug, usually IV, as a bolus or to effect in to facilitate endotracheal intubation - Some times achieved by IM or inhalant agents |
| What is it a good idea to fill out before induction, post induction, pre intra and post surgery? | A checklist |
| What equipment needs preparing before induction of anaesthesia? | - Anaesthetic machine - Breathing System - IV catheter equipment - Intubation equipment - Monitoring - Fluids - Draw up and label drugs |
| What equipment is required for endotracheal intubation? | - Laryngoscope - Tubes - Local anaesthetic (cats) - Tie - Cuff syringe - Swab, suction, mask for pre-oxygenation, stylet / bougie |
| What features of the endotracheal tube need to be considered? | - The size (width) of the tube - The length |
| How can you select the right size endotracheal tube? | - Direct palpation of the mid neck region of the trachea - Assessment of the width of the nasal septum - Previous experience |
| What is the general rule with sizes of the endotracheal tube? | 10mm ETT is suitable for a 20kg dog, an 8mm ETT for a 10kg dog and a 4.5-5mm uncuffed tube is suitable for a typical adult cat |
| What considerations are there with brachycephalic breeds? | - Preparation is key because may need to assist breathing quickly - May have hypoplastic tracheas so smaller required |
| What is the rule for using an ETT? | Largest tube than can be inserted and atraumatically should be used as the resistance to breathing increases 16 fold as the radius of the tube is halved |
| What is considered with the length of the ETT? | - Cut to size - Connector should be level with the incisor arcade and the tip at the point of the shoulder |
| What happens if the ETT is too long? | Resistance and dead space will increase and there is the risk of endobronchial intubation resulting in one lung ventilation and hypoxaemia |
| What happens if the ETT is too short? | - May be dislodged and the cuff may damage the larynx |
| Why is the use of a cuff in cats controversial? | Trachea can be easily damaged in cats |
| What are the pros and cons of using a cuff? | Uncuffed: - can use a larger diameter ETT - less trauma to the trachea Cuffed: - allow mechanical ventilation - extra care needed when moving animal |
| What should occur when moving an animal that has an ETT? | Great care - when changing recumbency the ETT should be disconnected from the breathing system after turning the vaporiser off |
| How do you prepare the animal? | - Thorough pre-anaesthetic assessment - Anticipate problems - Optimise condition - Premedication - Time for drugs to work - Calm environment - Avoid stress |
| What is the technique for induction of anaesthesia? | - Minimal effective restraint: i. animal in sternal or lateral recumbency ii. no hands around neck iii. one hand holds the upper jaw just behind the canines (use a tie?) iv. the other hand supports the base of skull - Never scruff cats - Optimise ventilation - don't compress chest |
| What is done in the induction of anaesthesia? | - IV catheter - Pre-oxygenation - Monitoring equipment - IV agent - Fluids |
| What is it always a good idea to do first before trying to place the endotracheal tube? | Preoxygenate for 2-5 mins with 100% oxygen at 3l/min |
| How can you test the depth of sedation? | Assess jaw tone (no fingers in mouth) and palpebral reflex |
| What is sprayed on cats arytenoids to prevent laryngospasm? | Lidocaine (check concentration and make sure that you're not going to overdose the cat) |
| What is the point at which an endotracheal tube can be placed? | Palpebral reflex is sluggish and jaw relaxed with no tongue curl when the mouth is opened |
| In what position should the head be held for placement of ETT? | Head and neck slightly hyperextended to allow visualisation of larynx (straight line) |
| How should the ETT be placed? | - Laryngoscope blade on base of tongue under epiglottis - Gentle pressure on base of tongue to displace soft palate - Advance ETT between arytenoids - Cough or reacts, additional injectable agent given - Resistance encountered, a gentle twist - Visually confirm placement |
| What occurs after the tube has been placed? | - Tied in place around the connector and then head or muzzle - Connected to breathing system and start administering 100% oxygen |
| How do you inflate the cuff? | - Inflate it - Listen carefully to the escape of air around the tube while your assistnat closes the APL valve and squeezes the reservoir bag at pressure of 15-20cmH2O - Inflate the cuff until no gas is heard to be escaping |
| What is the gold standard for confirming tracheal intubation? | Capnography |
| How else can it be confirmed that the tube is positioned correctly? | - Visualisation of the tube between the vocal folds - Condensation inside tube - Appreciation of air movement (don’t use hair) - Don’t press on thorax!: False positive, Reflux, Reduce FRC |
| What happens if the cuff is leaking? | - Difficult to achieve a stable plane of anaesthesia as volatile agent is not being delivered effectively - Waste anaesthetic gas pollution - Airway not protected in event of regurgitation and risk of aspiration |
| What is the risk if the cuff is over inflated? | Tracheal damage fibrosis, necrosis, tears, rupture |
| How should the ETT be placed if there is cervical damage? | Animal in lateral recumbency |
| What should happen is the animal is at risk of regurgitation/vomiting? | - Head and neck kept extended - Not to compress stomach - Quick induction and intubation - Cuff inflated whilst head up - Head can be lowered once inflated cuff |
| What is essential with an animal with intracranial disease during ETT? | Don't increase the intracranial pressure anymore |
| When is induction with a mask and inhalant gas performed? | Puppies Cats Exotics When an IV catheter cannot be placed before induction |
| What are essential features of the mask for inhalant induction agent? | - Proper size - Transparent - Takes longer with mask than IV - Not recommended in patients at risk of regurgitation/aspiration - Higher pollution |
| What is the issue with inhalant agents? | Pungent and cause airway irritation with consequent laryngeal spasm, salivation and increase airway secretions - Isoflurane more aversive than sevoflurane |
| When is induction of anaesthesia with a chamber and inhalant agent used? | Fractious cats and exotic animals |
| What are features of the chamber and inhalant agent for induction? | - Chamber appropriate size, transparent and airtight - Connected to non-rebreathing system - Cage opened once anaesthesia is induced and ambient pollution should be minimised by closing it immediately after moving animal |
| When can pharyngostomy intubation be used? | When oral surgery is being performed - Need to be trained |
| What are the most common complications during induction of anaesthesia? | - Apnoea - Laryngospasm - Failed intubation - Airwar occlusion |
| Why does apnoea occur? | Generally caused by respiratory depression after administration of induction agent: - Administered over 60-90 seconds at appropriate dose - Assisted ventilation should be available |
| In what species is laryngospasm most seen? | Cats |
| How should larygnospasm be prevented? | Lidocaine on arytenoids, 30-60s before ET intubation - Attempt intubation when adequate depth of anaesthesia is achieved |
| What should happen is larygnospasm occurs? | - Provide 100% O2 - Increase depth of anaesthesia by administering more injectable agent - Have a stylet and small sizes ready - If ETT cannot be placed a urinary catheter may be inserted into the trachea via the larynx and the ETT threaded over it - Consider letting the animal recover / use a larygneal mask airway / facemask rather than repeatedly attempting intubation and causing swelling of the larynx |
| What should occur if there is failed intubation? | Confirm using visual inspection and capnography - Re-insert if oesophageal intubation occurred |
| When may airway occlusion occur? | Between sedation and induction of anaesthesia - Paradoxical ventilation may indicate upper respiratory tract obstruction |
| What should be in a box ready to deal with difficult intubations? | - ETT of different sizes - Stylet - Urinary catheter - Laryngoscope - Lidocaine - Small oxygen cylinder - Tracheostomy kit - Suction device should be available |
| What is the technique of laryngeal mask airways in dogs and cats? | - Supraglottic airway device - Proximal end similar to ETT and connected to an elliptical mask with cuff on the distal end - Non-invasive method to create an airtight seal - Correct placement confirmed by capnogram, no audible leak, no abnormal respiratory noise and adequate thoracic excursions during respiration |
| When can laryngeal mask airways be useful? | - Difficult airway intubation - Multiple anaesthetics - Situations where tracheal trauma should be minimised |
| Why are perianaesthetic morbility and mortality higher in rabbits than cats and dogs? | - Underlying and often subclinical disease - Lack of familiarity - Small size: difficult placement of IV catheter, difficult doing of drugs, difficult dosing of fluid therapy, problems with equipment - Challenging endotracheal intubation - Delicate gastro-intestinal system |
| What needs to be remembered in the preparation of rabbits? | - Starving rabbits is not necessary - Stabilise the rabbit before GA - Avoid any stress - Use gentle handling - Place an IV catheter before induction of anaesthesia: the use of EMLA cream may be beneficial - Pre-oxygenation may be useful - Uncuffed endotracheal tubes are generally used in rabbits |
| How might induction of anaesthesia be achieved in rabbits? | - IV induction agent (preferable) - Inhalant agent administered via a mask or induction chamber |
| What are the 3 methods for endotracheal intubation in rabbits? | - Blind endotracheal intubation - Endotracheal intubation with otoscope or laryngoscope - Endotracheal intubation with endoscope |
| What is blind endotracheal intubation? | - Hold the head of the rabbit with your non-dominant hand and extend the neck - Introduce gently the endotracheal tube down the trachea while listening to breath sounds - The rabbit may cough when you reach the larynx - If breath sounds are not heard any more, oesophageal intubation may have occurred |
| What is endotracheal intubation with otoscope or laryngoscope? | - Visualization of the larynx is facilitated by the use of an otoscope or laryngoscope - A boogie or stylette is introduced in the trachea (avoid trauma to the trachea) - The endotracheal tube is threaded over the boogie or stylette |
| What is endotracheal intubation with endoscope? | - Visualization of the larynx is facilitated by the use of an endoscope - A boogie or stylette is introduced in the trachea (avoid trauma to the trachea) - The endotracheal tube is threaded over the boogie or stylette |
| What are techniques for use of laryngeal mask airways in rabbits? | - Placement of a LMA is usually easier than endotracheal intubation - The dose of induction agent required to place a LMA is lower than endotracheal intubation |
| What should occur immediately after tracheal intubation? | - Peripheral pulses palpated - Endotracheal tube secured - Cuff inflated - Depth of anaesthesia assessed - Maintenance of anaesthesia monitored - Hands on monitoring of vital parameters and records made |
| During maintenance of anaesthesia what should happen? | - Record data on the anaesthetic record - Monitor depth of anaesthesia |
| Why should ocular lubrication be applied as soon as possible after induction and regularly during anaesthetic and occassionally post surgery? | - Formation of pre-corneal tear film is reduced during anaesthesia and sedation - Eyes become dry and predisposed to damage, and vulnerable to trauma when moving |
| Why does body temperature have to be controlled for animals during anaesthesia? | Body temperature controlled by hypothalamus and so hypothermia is common during anaesthesia |
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