2. In spite of safer anaesthetic protocols and anaesthetic
techniques serious accidents and emergencies are not
uncommon
Induction of general anaesthesia affects
◦ Cardiac output
◦ Blood pressure
◦ Peripheral perfusion
◦ Alveolar ventilation
◦ Temperature regulation
◦ Intracranial pressure.
Further, addition of detrimental consequences of surgery
add to the impact of anaesthesia
3. Anesthetic emergencies
▪Respiratory complications that result in anesthetic
emergencies
▪Cardiovascular complications that result in anaesthetic
emergencies
▪Other complications that result in anesthetic emergencies
▪Cardiopulmonary resuscitation
4. Human error
Miscalculation of drug dose: Common
Mislabeling of syringes or misfiling of
wrong vaporizers
Equipment failure or misused devices
Inadequate monitoring
5. Aspiration
Occurs in absence of endotracheal intubation
Foreign material with acidic pH (stomach contents)
Causes:
◦ Insufficient preoperative fasting
◦ increased intra abdominal pressure due to surgical manipulation
◦ Mega-esophagus
Prevention
◦ Position head lower than oesophagus
◦ Use cuffed endotrachealtubes
◦ Suction of gastric or oesophageal contents:Horses
◦ Postponesurgery if required
◦ Use safer anaesthetic/preanestheticswith antiemetic property.
Treatment
◦ Cleaning and suction of aspirated contents
◦ Broad spectrumantibiotics, analgesics and steroids
7. Apnea
Most often induced by I/V induction
agent.
Treatment: correctthe cause
Causes
overdose of anaestheticagent –
thiopentone, propofol , etomidate,
alfaxalone, ketamine
Large dose of drug given in rapidbolus
Depression of CNS
Jerky
respiration
Limb and jaw
movement
gasping
No tone in
muscles
Signs of
apnoea
If overdose
of inhalant
anaesthetic
–artificial
ventilation
If overdose of
injectable
anaesthetic-
I/V fluids
Opioid depression-
antagonist
Naloxone
Etorphine-
diprenorphine
Alpha 2 agonist-
yohimbine /
atipamezole
Analeptic drugs
– Doxapram-
upto 2mg/kg I/V
.
Propofol, etomidate ,
alfaxalone given slowly .
If still ,no respiration-
controlled ventilation @ 10-
15/min with oxygen will be
necessary for several minutes.
8. Hypoventilation:
It occurs when alveolarventilation decreases , resulting in increase in arterial carbon dioxide
tension(paco2) above normal.
Causes : 1. Anaesthetic drugs – halothane, isofluraneafter opioid premedicationin dogs and
in cats due to ketamine.
2. neurologicaldisease , Lung disease
3.restricted air flow – partialairway obstruction
4. Anaestheticmachine malfunction–sodalime canisterexhausted
5. Movementof ribs restricted – due to external pressure , fracture , neuromuscularblocking
agents.
DIAGNOSIS –slow respirationrate, rapid shallowbreathing,
confirmed by ETCO2values 45 mmHg in arterial blood.
Treatment :
spontaneousventilationgiven if patient is young and healthy.
Lighten the anaesthesia
controlledventilationwhen breathing is moderatelyor severely depressed or in geriatric and
sick animals.
9. Loss of airway :
Loss of airway is a conditionthat has resultedinthe
deaths of healthy patients andis a primary reasonfor
anesthetic emergenciesinall species.
due tothe CNS depressionandrespiratory depression
inducedby general anesthetics.
Inadvertent extubationandplacement of the
endotracheal tube intothe esophagus , blindintubation.
Brachycephalic breeds–elongatedsoft palate , can’t
breathe withnostrils.
Endotracheal tube occlusionby mucous plugs or blood.
Kinking of the endotracheal tube.
Overinflationof the endotracheal tube cuff.
Endotracheal tube is tooshort.
Endotracheal tube is toolong, resulting inone-lung
ventilationfromimproper tube placement.
Laryngeal paralysis or tracheal collapse- obstruction
during recovery.
Prevention
Extend neck and draw tongue out
in non intubated animals
Apply local anaesthetic spray at
larynx during intubation so that
animal retains tube for longer time.
Remove all clots before ending the
operation esp. during tonsillectomy
, tooth extraction .
Keep animal in lateral position
during recovery
Try to keep ETT in place for longer
period during recovery.
10. Hypoxemia:
Hypoxemia is a common complicationof general anesthesia.
The major causes of hypoxemiaor when low arterial oxygen tension
PaO2 levelsare 50–60 mmHg
due to equipmentfailure-oxygenflow meter is not turned on , empty
cylinder , faulty valve.
endotrachealtube becomes kinked or obstructed
▪DIAGNOSIS- signs and via pulse oximetry or bloodgas analysis
Treatment – supply 100% oxygen by ETT, ambu bag
Check airway obstruction, anaestheticmachine .
The administrationof positive end expiratorypressure(PEEP) can be
helpful in the hypoxemic patient, as it increases alveolarparticipation
in gas exchange and may recruit collapsedalveoli.
Hypoxia secondary to hypoventilation canlead to prolonged recovery
and adverse consequences such as blindness when cerebral blood flow
and oxygen delivery are compromised during general anaesthesia.
Animal appears to
be waking up or at
light depth of
anaesthesia
Gasping, cyanotic
or white mucus
membrane
CVS- initially
tachycardia ,
hypertension
Later on
bradycardia ,
hypotension
11. Tachypnea
Rapid , shallow breathing
Causes :
Lighter plane of anaesthesia
Anaesthetic drugs – opioids ,
halothane
High inspired CO2 – exhausted
sodalime canister
Hypoxemia
Hyperthermia – temp > 102.5 F
Diagnosis – panting , Hypercarbia
( high ETCO2) and hyperthermia
Naloxone
@ 0.02 –
0.04mg/kg
IV
Artificial
ventilation
Check
anaesthestic
machine
Treatment
13. Haemorrhage
Acute hemorrhage from lacerationof major vessel:Immediate clamping and
ligation
In general- PCV >20% and TP >3.5 g/dl in the anesthetizedpatient is desirable.
If bloodloss is >20 ml/kg and PCV and TP are lower than the above values-
results in shock – signs like tachycardia , hypotension, weak pulse, white mm ,
labouredbreathing.
Normal bloodvolume of dog – 88ml/kgand cats – 56ml/kg
Signs:
◦ Weakpulse, Lower bloodpressure,Deeper anaesthesia, Palemucous
membranes
Fluidand bloodloss
Suctionof blood from operativefield
lactatedringer’s solution@2.5 times volumeof bloodlost or hypertonic saline
solution-LA
Colloidsolutions, plasma or bloodtransfusion-SA
17. Hypotension
Inadequate tissue perfusion
◦ Vital organs, Myopathy
◦ MAP in healthy dogs and cats – 90-100mmHg
◦ Inhalant anaesthetic in dogs decreases MAP to 60mmHg
◦ Causes
Anaesthetic overdose
Hypovolemia due to intra-operative bleeding or peri-operative fluid
deficit
Treatment
Lighten anaesthetic depth
Treat hypotension with fluids i/v fluids- crystalloids @ 10ml/kg over
15min or dextran @ 5ml/kg
Positive inotropes: Dobutamine/Dopamine @ 3-10ug/kg/min I/V
epinephrine
18. Premature ventricular contractions
May lead to ventricular fibrillation
Causes
Myocardial contusions from trauma
GDV, Pain, Acidemia, Hypoxia or hypercapnia
Sympathetic imbalance
Drug induced: Thiopental, halothane
Treatment
Correct/Remove cause(s)
Drugs:
◦ Lidocaine (1-2 mg/kg)
◦ Beta adrenergic blockers: Propranolol(0.02-0.06 mg/kg)
19. Cardiac arrest
Causes
Hypoxia is the ultimate cause
Signs
Absence of pulse or a palpable or audible heart
Other symptoms
◦ Apnea, Loss of consciousness, loss of corneal ocular reflexes,
eyes are fixed, wide open, pupil dilated with absence of light
reflex
20. Cardio-pulmonary resuscitation
Aim to develop effective blood flow and re-establishing
heart beat and respiration/ventilation
Rules of ABCDEF
A. Airway
B. Breathing
C. Circulation
D. Drugs
E. Evaluation
F. Follow up
21. A. Airway
Establish patent airway
Clear the airway from obstructions: Aspirate
Endotracheal intubation or
Transtracheal catheter ventilation or tracheostomy
22. B. Breathing
Administer pure oxygen (6-12 breath / min) to alveoli and to
eliminate carbon dioxide
Visible respiratory movements of chest wall and diaphragm similar
to sleeping animal
Simultaneous chest compression: 5/breath
IPPV-LA
23. C. Circulation
Lateral recumbency on firm surface and compress chest.
Compress heart from both sides (small dogs) or at the junction of
dorsal and middle third of 5th-7th ICS (large dogs).
Compress the chest to depress the chest wall by 30%
Blood flow by compression will temporary sustain cerebral &
myocardial viability, if oxygen adequate.
Complications:
◦ Sternal and Rib fractures
◦ Blunt traumatic damage
◦ Pneumothorax
EXTERNAL CARDIAC COMPRESSION (3-4 minutes)
24. Circulation…..
Open Chest cardiac message: for 5 mins
Cardiac message @ 80-100/min
Drug administration into heart
Often required in pneumothorax, hemothorax, flail chest, severe
obesity, DH
25. D. Drugs
Epinephrine: 0.02-0.2 mg/Kg. repeat after 3-5
minutes, if needed
Sodium bicarbonate: 0.5-1mEq/kg for each 10 minutes of arrest.
Intravenous fluid: 10-20 ml/kg
26. Routes of drug administration
Central vein (Jugular)
Tracheal tube lumen (Ephedrine, atropine, lidocaine -2-3 times iv
dose)
Intra osseous and sublingual routes (dogs)
Intra cardiac, when chest is open: epinephrine
28. F. Follow up
Post-resuscication cardiac arrest is very common.
Ionotropic support (dopamine 5-10 mcg/kg/min)
Intensive monitoring at least for 24 hours.
29. Temperature monitoring
HYPOTHERMIA: Most common cause of death during recovery
◦ Depression of hypothalamus
◦ Long surgeries
◦ Maintenance of ambient temperature at least 26ºC
◦ Wrapping in warm water blankets
◦ Luke warm IV / IP fluids
HYPERTHERMIA
◦ High ambient temperature
◦ Closed circuit
30. Malignant hyperthermia
Decreased control of intracellular calcium resulting in
release of free unbound ionized calcium
Increased metabolism to provide ATP to drive calcium
pumps to maintain homostasis
Rigidity occurs when unbound calcium approximates the
contractile threshold
Dantrolene (2mg/kg): blocks sarcoplasmic calcium
release without affecting uptake
Avoid potent inhalation anaesthetics (halothane) and
depolarizing muscle relaxants
31. Brachycephalic Breed concerns
Anatomical handicaps
◦ Stenotic nares
◦ Elongated soft palate
◦ Everted laryngeal ventricles
◦ Hypoplastic trachea
◦ Large thick tongue
Goals
◦ Rapid smooth induction
◦ Pre-oxygenate using face mask
◦ Quick smooth recovery
◦ Avoid drugs with known emetic reflex
◦ Leave endotracheal tube as long as possible
◦ Observe recovery
32. Perivascular injections
Causes pain, abscess, necrosis, thrombosis
Displaced catheters, leaky vessels
Use of irritant drugs: Thiopental: Barbiturate slough
Treatment
Use catheters
Dilution with saline
Subcutaneous lidocaine
Subcutaneous steroid
Pressure bandage application
33. Injuries
Position of animal and its parts
Limbs are tied too tight and inhibit venous drainage
◦ Radial paralysis
◦ Myositis
Corneal dehydration: Eye ointment
Laryngeal trauma with endotracheal tube: Cough
Over inflation of cuff
High pressure induced injury
Noxious stimuli
34. Post anaesthetic accidents/ emergencies
Myositis: Horses and bulls
• Prolonged recumbency and stormy recovery
• NSAIDs, Fluid therapy
• Comfortablelying area
• Use rubbertubings/paddedor Pneumatic beds
• Provided padded recovery room
Radial paralysis: Heavy bovine and horses
• Prolnged recumbency and cross tying
• NSAIDs and nerve tonics
• Provide comfortable lying area
• Use padded tables/pneumaticbeds
Coughing: Dog/cat : Injury to larynx/trachea, Overinflation of cuff
• Use xylocaine gel/liquid paraffin/lignocaine spray during intubation
• Use fresh/disposable endotracheal tubes
Drying of cornea
• Use eye ointment
Regurgitation: Cattle/buffalo/dogs (rarely)- Horses do not vomit
• Use cuffed endotracheal tubes
• Lower head of animal
35. Contd……
Prolonged recovery: dogs
• Fluid therapy and urinary cathterization
• Provide oxygen: ET/nasal tube
Limb injuries/Fractures: During recovery from general anaesthesia and
epidural/spinal anaesthesia
• Provision of slings in recovery room
• Avoid over dose of local anaesthetic
Always flush mouth of horse/bovine to prevent feed going into trachea
While operating on young foal
• Use sedatives for dam: Dam is a patient too
Unusual recubency
• Monitor oxygenation
