reaching purpose; students quick and easy reference

1. ANESTHETIC EMERGENCIES
Dr Warson Monsang

2. -The most serious emergencies during anesthesia are related to INSUFFICIENCY or
FAILURE of respiration or blood circulation.
- Regurgitation, Vomition, Anesthetic overdose, Abolition of body temperature
regulation may also occur.
- Untreated RESPIRATORY FAILURE eventually leads to CIRCULATORY FAILURE.
- Irreversible brain damage occurs 4-6 mins after RESPIRATORY ARREST and 2-4 mins
after CIRCULATORY ARREST.

3. - Causes of respiratory emergencies -
i. Drug depression
ii. Air-way obstruction
iii. Faulty positioning of the animals
iv. Low levels of inspired oxygen
v. Mechanical interference with the movement of thoracic wall or diaphragm
vi. Diseases of respiratory and / or cardiovascular system
1. RESPIRATORY INSUFFICIENCY & ARREST

4. RESPIRATORY INSUFFICIENCY & ARREST

5. RECOGNITION OF RESPIRATORY INSUFFICIENCY AND ARREST
1. Both tidal volume and respiratory rate is decreased.
2. PARADOXICAL RESPIRATION – in deep anesthesia, the intercostal muscles become
paralyzed and the thoracic wall moves inward rather than outward during inspiration.
3. Cyanosis – a sign of inadequate oxygenation is present. An animal breathing 100% oxygen
will not become cyanotic for 8-10 mins after total respiratory arrest.
4. Increased heart rate, cardiac output and blood pressure are seen as a result of
sympathetic stimulation.
Pale mucous membranes, flaring of the nostrils and movement of the mouth and larynx
on inspiration may also be observed.
Hypoxia and cardiac arrhythmia may also occurred.

6. TREATMENT OF RESPIRATORY INSUFFICIENCY AND ARREST
1. Initiating cause should be removed and high levels of oxygen be administered.
2. Assisted or controlled ventilation either manually or with the aid of mechanical
ventilator should be provided.
3. Air way patency and circulatory adequacy should be checked and artificially,
controlled ventilation with 100% oxygen be started by compressing rebreathing bag
or use of mechanical ventilator.
4. In case of reflex respiratory failure due to endotracheal catheterization, the tube
should be removed and larynx be totally desensitized with topical anesthetic.

7. 5. Bronchial spasm is usually self limiting and may require treatment with MEPERIDINE
1-2 mg/kg or AMINOPHYLLINE 1-2 mg/kg in dogs.
6. If respiratory failure is partially or completely due to NARCOTIC depression,
antagonists like NALORPHINE or LEVELLORPHAN may be given intravenously to
effect or specific antagonists be used.

8. - Causes of respiratory emergencies -
i. Excessive anesthetic or narcotic depression
ii. Severe hypotension
iii. Hypovolaemia
iv. Peripheral vasoconstriction (traumatic shock) or vasodilation (septic shock)
v. Obstruction of venous return. Intermittent positive pressure ventilation, presence
of excess intra-abdominal gas or fluid or pressure of mass on posterior vena cava
like gravid uterus leading to reduced cardiac output.
vi. Hypoxia, hypercapnia
vii. Severe electrolyte imbalance
2. CARDIOVASCULAR INSUFFICIENCY & ARREST

9. CARDIOVASCULAR INSUFFICIENCY & ARREST

10. RECOGNITION OF CARDIAC INSUFFICIENCY AND ARREST
1. Sudden changes in the respiratory pattern, cyanosis of mucous membranes or surgical
site, reduced bleeding at the surgical site, increased capillary refill time, complete loss of
peripheral arterial pulse, decrease in the intensity of heart sounds, progressive and
persistent tachycardia or bradycardia, and pulse and electro-cardiographic irregularities.
2. Arrhythmia mainly ventricular premature contraction. Atrial flutter, atrial fibrillation,
atrioventricular block and ventricular tachycardia are also seen.
3. Estimation of adequacy of blood pressure by palpating femoral or lingual artery.
Recording of capillary refill time – prolonged capillary refill time may be due to reduction
of cardiac output or blood pressure or to a compensatory sympathetic vasoconstriction.

11. MANAGEMENT OF CARDIOVASCULAR INSUFFICIENCY
INITIAL TREATMENT –
1. Administration of anesthesia should be immediately stopped and adequate
oxygenation is achieved by manual or assisted ventilation and administration of high
levels of oxygen.
- the patency of airway should be ensured.
- the anterior end of the animal should be lowered by 20-30 degrees.
2. Closed-thoracic cardiac massage should be commenced as quickly as possible and
should not be interrupted as it takes 1-2 mins to re-establish an effective blood
pressure.

12. 3. Blood or plasma expander or balanced electrolyte solution low in potassium should
be rapidly infused in Dog at the dosage as high as 50-100 ml/kg.
4. Sodium bicarbonate should be administered at the rate of 25mEq/10kg BW per 10
mins of circulatory failure.
5. Central venous pressure and arterial blood pressure, temperatures, acid-base and
ECH monitoring should be commenced immediately, if facilities are available.
6. If external cardiac massage is ineffective either due to presence of fractured rib,
cardiac temponade, pneumothorax and ventricular fibrillation, a decision to open
the thorax and open heart message be taken.

13. 7. The heart should be grasped between thumb and fingers and squeezed gently and
firmly after opening the thorax through 5th or 6th left intercostal space.

14. MANAGEMENT OF CARDIOVASCULAR INSUFFICIENCY
DEFINITIVE TREATMENT –
1. Cardiac stimulants – intracardiac injection of 0.5 – 2 ml of 1:10,000 epinephrine
solution is used. The animal should not be under halothane, methoxyflurane,
cyclopropane or chloroform anesthetics.
2. Isoproterenol is a safer cardiac stimulant for use with halogenated anesthetics. The
initial dose is 0.05 mg in 500-600 ml electrolyte solution and the solution is given to
effect.
3. NE (nor-epinephrine) can also be used to reverse cardiac asystole. 1 mg of 1:100
solution should be diluted in 500-600 ml of fluid and given to effect.

15. 4. CALCIUM GLUCONATE, 5-10 ml of 10% solution or CALCIUM CHLORIDE, 1-3 ml of 10%
solution should be used to strengthen the already existing heart beat.
5. CARDIAC DEFIBRILLATION can be achieved by oxygenation and perfusion of heart in
smaller animals. In order to maintain it, LIDOCAINE 1 ml/kg should be given
followed by cardiac massage with a further attempt by electrical defibrillation.

16. POST-RESUSCITATIVE MEASURES –
1. Administration of high level of GLUCOCORTICOIDS:
HYDROCORTISONE 50-75 mg/kg
DEXAMETHASONE 1-2 mg/kg, with an osmotic diuretic like MANNITOL 1mg/kg BW.
2. Animal should be kept n high levels of oxygen and its ventilation monitored closely.
3. Vital signs, arterial and venous blood pressure, ECG and acid-base should be
monitored to assess the circulatory adequacy.
4. Body temperature of the animal should be kept above 350C.

17. - REGURGITATION is the passive discharge while VOMITING is the active discharge of
stomach contents into the pharynx.
- regurgitation occurs in small animals during anesthesia in dorsal recumbency since
relaxation of the cardia allows gastric contents to flow in the esophagus.
- in RUMINANTS, pressure on the rumen produced by recumbency along with relaxation
of cardia are the probable cause of regurgitation.
3. REGURGITATION & VOMITION

18. REGURGITATION & VOMITION

19. REGURGITATION & VOMITION

20. Following steps should be taken into considerations to minimize the hazards of
regurgitation –
1. Intubation should be performed as soon as possible. Cuff of the tube should be
inflated, if laryngospasm is suspected. Intubation should be done under a topical
anesthesia to suppress laryngeal and tracheal reflexes.
2. Ruminants should be positioned in recumbency in such a way so as to minimize
regurgitation and aspiration. Sternal recumbency with head down is preferred or
chest be preferably be higher than both the abdomen and head.
3. As soon as the retching movements occur after vomiting in small animals, the
operating table should be tilted so that the patient is positioned with its head down
and 100% oxygen given either through the mouth or nasal catheter.

21. 4. Pharynx should be cleared off from vomitus manually or through suction.
Endotracheal tube should be inserted after cleaning the trachea, and the cuff of the
tube should be inflated to prevent further aspiration. Oxygen administration should
be continued.
5. If gastric juice goes into the trachea, apnoea, cyanosis, tachypnoea, hypotension,
bronchospasm may develop. On account of presence of gastric juice, pulmonary
oedema, patchy atelectasis, hemorrhagic areas may develop in the lungs.
- Following drug therapy is indicated to support the patient and to prevent infection and
inflammation of respiratory tract.

22. 1. HYDROCORTISONE injection intratrachealy and intravenously followed by
intramuscular injections for next 2-3 days.
2. Broad spectrum antibiotics wither intramuscular or intravenous to minimize
secondary complications.
3. Adequate oxygenation by continued administration of 100% oxygen through a nasal
catheter or with a tracheostomy tube.
4. Bronchodilator like AMINOPHYLLINE, 0.05 – 0.2 gm intravenously in DOGS for 2-3
days.
5. Expectorant cough mixture may be used to remove vomitus.

23. - Overdose can occur after administration of inhalant or parenteral agents like
barbiturates. Inhalation anesthetics can be removed from the body by controlled
ventilation and barbiturates once administered can not be removed quickly.
-- on account of overdosage, respiration is depressed and leads to RESPIRATORY
ACIDOSIS.
4. ANESTHETIC OVERDOSE

24. - Following measures should be taken to manage patients with barbiturates overdosage -
i. Hyperventilation to reduce CO2 tension and increase blood pH.
ii. Sodium-bicarbonate intravenous to increase pH and for ionization of barbiturate.
iii. Blood volume and urinary output are maintained by administration of fluids, saline
solution or diuretics like FUROSEMIDE intravenous or intramuscular.
Diuretics may be repeated every6-8 hrs .
iv. Normal body temperature is maintained and hypostastic congestion of lungs prevented
by frequent turning of the animal.

25. - Body temperature regulation is abolished during anesthesia.
-- several agents reduce peripheral vasoconstriction and facilitate heat exchange.
-- heat also dissipates from the body due to the use of non-rebreathing techniques,
surgical exposure of tissues and body cavities ad by intravenous administration of fluids
of low temperature.
- as the body temperature falls, the requirement for anesthetic is reduced and the
animal may be slow to recover and exhibit depressed reflexes after the operation.
5. TEMPERATURE REGULATION

26. TEMPERATURE REGULATION

27. - It is therefore essential to observe the following points to maintain body temperature
during anesthesia –
i. operation theatre temperature should be at least 1000F (37.90C) and the animal be
kept warm during anesthesia by pads, lamps, etc.
- animal coming out of anesthesia should be kept in warm and comfortable
place. It should be kept in mind that excessive heat or injudicious use of warming
devices may cause burn or even death of the animal.
ii. Intravenous fluids being administered should be warmed to body temperature.