Canis ISSN: 2398-2942

Anesthesia: for thoracic surgery

Contributor(s): Sheilah Robertson

Special considerations

Ventilation
  • Negative intra-thoracic pressure is lost once the pleural cavity is open to the atmosphere. Therefore intermittent positive pressure ventilation (IPPV) is essential.
  • Ventilation must be adequate to supply oxygen to, and remove carbon dioxide from, the alveoli.
  • Difficulties can be expected when pre-existing problems of adequate oxygenation are present or develop as a sequel of mismanagement before or during anesthesia.
  • Insufficient ventilation under anesthesia on room air will result in the partial pressure of oxygen in the alveoli becoming insufficient so that unsaturated hemoglobin leaves the lungs (hypoxemia). Also, the elimination of carbon dioxide is decreased ’ hypercapnia and respiratory acidosis Acid base imbalance.
  • If 100% oxygen is administered then hypoventilation will result only in hypercapnia and acidosis (without hypoxaemia) unless hypoventilation is marked.
  • The cardiovascular system must be maintained to supply oxygen and substrates to and remove carbon dioxide and waste metabolites from the tissues.
Dysrhythmia
  • Manipulation within the thorax may cause cardiac dysrhythmias Heart: dysrhythmia , occlude major blood vessels and compress lobes of the lungs.
    Communication between anesthetist and surgeon throughout the procedure is essential
Hypothermia
  • Hypothermia develops quickly when the thoracic cavity is open, especially in small animals. Every attempt should be made to prevent this ’ use circulating hot water beds, bubble wrap, thermovent and a warm operating environment.
Hemorrhage
  • There is the potential for severe, acute hemorrhage. Have a venous catheter in place before induction of anesthesia and provide appropriate fluid therapy throughout.
Analgesia
  • Thoracotomy is a very painful procedure. Effective analgesia Analgesia: overview will reduce post-operative morbidity and speed recovery.

Pre-operative assessment

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Management

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Positioning

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Analgesia

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Further Reading

Publications

Refereed papers
  • Wagner A E et al(1998)Monitoring adequacy of ventilation by capnometry during thoractomy in dogs. JAVMA212(3), 377-379.

Other sources of information

  • Hall L W & Clarke K W (1991)Veterinary Anaesthesia.9th edn. Balliere Tindall. pp 363-367. ISBN 0 7020 1421 4.


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