Essentials of recovery

What are the risk factors of undergoing anaesthesia in dogs & cats?

• Age 

• Weight 

• Higher ASA status 

• Emergency procedures 

• Nature of procedure 

• Breed 

What are the risk factors of undergoing anaesthesia in horses?

• ASA status

• Age Surgery type

• Prolonged duration of anaesthesia

• OOH surgery

What are the causes of anaesthesia-associated mortality in horses?

• Intraoperative cardiopulmonary arrest (usually within first 30mins)

• Fractures 

• Post-anaesthesia myopathy 

• Spinal cord malacia 

• Post-anaesthesia neuropathies 

• Post-anaesthesia airway obstruction 

What are the factors affecting quality of recovery in horses?

• Anaesthesia time 

• OOH 

• Surgery type 

• Increased age 

• Temperament 

• High body weight 

• ASA status

• Recumbency

• Orthopaedic procedure

• Hypotension, hypoxaemia 

• Time to stand 

Why is the recovery phase of anaesthesia dangerous?

• Level of physiological support (e.g. secure airway, oxygen, fluids) greatly reduced

• Level of monitoring reduced

• Some problems manifest themselves after a delay

• May be specific dangers relating to species, breed, health status or type of surgery

List some common recovery problems

• Hypothermia

• Emergence delirium

• Hypoxaemia

• Hypo/hypertension

What are the causes of hypothermia post anaesthesia?

Anaesthesia: drugs, clipping, surgical spirit, open body cavity

What are the consequences of hypothermia post anaesthesia?

• Reduced MAC requirement

• Delayed recovery

• Shivering —> increased oxygen consumption

• Delayed wound healing

How can hypothermia in anaesthesia be prevented?

• Heat pads, forced air blankets, flush body cavities with warm fluids, blankets

• Make sure to monitor temperature —> be aware of potential hyperthermia and/or burns —> never allow direct contact between patient’s skin & heating devices 

How long does emergence delerium last, and who is at risk when patient suffering with it?

Self limiting, 5-15 minutes

Risk of injury to animal and handlers

How is emergence delirium prevented/treated?

• Chemical (sedation) or physical restraint

• Reduce stimulation, reduce noise and light level

• Ensure adequate analgesia

What are the possible causes of hypoxaemia in recovery?

• Airway obstruction

• Inadequate ventilation (e.g. patient still too deeply anaesthetised or too painful to breathe post-thoractotomy)

• Poor gas exchange (e.g. pnuemonia/ congested lungs/ atelectasis)

What are the clinical signs of hypoxaemia in recovery?

• Cyanotic mucus membranes

• Tachypnoea/dyspnoea

• Stertor/stridor (obstructed airflow)

• Reduced level of consciousness

How do you treat hypoxaemia in recovery?

• Ensure patent airway

• Ventilate

• Oxygen supplementation

(investigate potential causes & treat accordingly)

—> Analgesia

How can hypoxaemia in recovery be prevented?

Only extubate when animal can protect its own airway

How can you prevent/treat hypotension/hypertension in recovery?

Utilise fluid therapy/vasoactive drugs during and after anaesthesia

(Only tends to be a problem when animal critically ill)

List some of the GI complications that can occur in dogs and cats in recovery?

Gastric reflux/regurgitation/aspiration stricture

What may increase the risk of gastric reflux post anaesthesia in dogs and cats?

• Repeated anaesthetics

• Frequent recumbency change 

• Orthopaedic surgeries

• Large/ giant breed dogs

• Barrel-chested dogs

What is the protocol for gastric reflux in dogs?

• Check ET tube cuff

• Head down and suction oropharynx

• Check pH of regurgitate

• Place stomach tube and lavage stomach and oesophagus until clear fluid comes out

• ?bicarbonate / sucralfate

What complications may happen in cats during recovery from anaesthesia?

• Tracheal tear/rupture

  • Related to over inflation of ET tube cuff and predominantly in dental cases

• Blindness

  • Related to cerebral ischaemia because of hypotension or use of mouth gags

How can tracheal tear in cats be prevented?

Consider pharyngeal packing as an alternative measure to protect the airway

What complications may happen in horses during recovery from anaesthesia?

• Colic

• Myopathy/neuropathy

• Fracture

What complications may happen in ruminants during recovery from anaesthesia?

• Regurgiation/aspiration

• Bloat

What complications may happen in pigs during recovery from anaesthesia?

• Respiratory obstruction

• Hyperthermia/sunburn

How can recovery problems be reduced?

• Monitor animals as much as possible —> HR, RR, palpate pulse, pulse oximetry etc.

• Should be able to lift head and swallow unaided —> only extubate once swallowing (if not swallowing and extubate = can regurg)

• Make sure at adequate temp —> avoid hypothermia

• Quiet, non-slippery environment (particularly for horses, who try to get up too early)

• Try and make sure bladder empty prior to anaesthesia (a2 agonists potent diuretics)

• Extubate cat earlier than other species —> prone to laryngeal spasm —> observe closely

• Communication to others if they will be responsible for recovery about any complications

• Anticipate any problems if possible

• Rapid recognition/ intervention reduces severity

Why is the recovery phase of anaesthesia where most patients die?

(recovery phase = within 48 hours post anaesthesia)

Patient is no longer under constant monitoring but drugs still in system & physiological functions still compromised

How is laryngeal spasm (cats) treated?

• Re-anaethetise if in resp distress i.e. get IV access & induce again, everything relaxes and able to get ET tube down (larynx relaxes) —> avoid hyperventilation

• No IV in/can’t get another IV in? —> calm (sedate) by IM a2 agonist or butorphanol to relax

• Dog urinary catheter used to get through laryngeal spasm —> get airflow through with 2ml syringe, disconnect plunger, administer O2 from ET tube connected to end of syringe

• Can’t get anything through laryngeal spasm (arytenoids clamped shut) - needle through tracheal rings to provide airway —> as big a needle as poss e.g. 18G —> not likely to get infection in lungs, so deal with consequences later

• Can leave ET tube in trachea to keep airway patent

When should you need to give a breath during post-induction apnoea?

• Check cuff adequately inflated —> give breath, see if leak can be heard around ET tube

• If sPO2 starts dropping —> move pulse oximeter because may be inaccurate

• Should start breathing again on their own but if not give a breath when it has been ~2-5mins

• Want CO2 to build up to give stimulus to breathe on their own so don’t want to give a breath straight away

• If too light plane of anaesthesia? Give breath to flow inhalational agent through

• Severe resp distress (hypoxaemic) = give breath

• Raised intracranial pressure e.g. brain tumour or RTA = high CO2 build up = vasodilation of brain = even more increase intracranial pressure = GIVE BREATH