VPB 121: Veterinary Physiology - II (2+1)

ARTIFICIAL RESPIRATION

• Artificial respiration is resorted to in cases of
  • cessation of respiration while under general anaesthesia
  • drowning where the animal has been rescued from water – mainly applicable for small animals;
  • poisoning by narcotics or paralytic substances
  • asphyxia from fumes, smoke, gases etc.

Method of administration

In large animals

• The animal is released from all restraints, head and neck are extended to allow a straight passage of air into the lungs and the tongue is pulled out. The elastic ribs are compressed by alternately leaning the whole weight of the body of a person on the hands kept pressed on the ribs and then releasing the pressure about once every 4 or 5 seconds, for the purpose of stimulating normal movements of breathing. As an alternative, a heavy person may sit himself with some vigour astride the ribs for about 4 or 5 seconds, rise for a similar period and then reseat himself.
• Inhalation of strong of ammonia upon a piece of cotton and held about a foot from the upper nostrils assists in inducing a gasp, which is sign of returning of respiration. The animal is turned on its sides every 2 or 3 minutes to prevent stasis of blood. As long as the heard continues to beat, attempts at resuscitation should be pursued. Resuscitators or mechanical ventilators are useful to give artificial respiration.  For pigs and sheep, the same procedures can be applied.

Dogs and cat

• Mouth-to-mouth or mouth-to-nose ventilation, which uses exhaled air to provide 16% O 2 can be used for artificial ventilation. The preferred technique is use of endotracheal intubation and providing ventilation with an anesthetic machine or mechanical ventilator.
• In another technique, the animal is laid on its side with the head at a lower level than the rest of the body. The palm of a hand is placed flat over the upper side of the abdomen and the other hand is placed on the rib cage, weight is placed on the hands for a second or two and then the pressure is released. The motions of artificial respiration should be faster than normal respiration, but a slight pause should always be observed before each rhythmic movement.

Resuscitators

• A frequently used resuscitator consists of mechanism for applying intermittent positive pressure and a facemask or a connector to connect the equipment with endotracheal tube. These apparatus forces air through the mask into the lungs during positive pressure cycle an allow air to flow passively out of lungs during the remaining periods.
• For controlled positive pressure ventilation, either orotracheal intubation or tracheotomy is indicated. The technique is used in comatose, anaesthetized or sedated animals