Anesthesia and surgery in birds

• These notes discuss anesthesia and surgery in birds.

Introduction

• Birds are highly susceptible to stress.
• They are small in size and not accustomed to handling.
• Anesthesia or sedation is frequently needed for various procedures.
• Limitations include the bird's size.

Anesthetic Indications

• Sedation is useful for exploration and minor procedures.
• Minor procedures include radiography and blood extraction.
• Anesthesia is also indicated for surgery and endoscopy.

Sedation

• It's useful in birds not accustomed to handling.
• Midazolam can be administered intranasally at 1-2mg/kg.
• It can also be given intramuscularly at 0.5-1mg/kg.
• If midazolam is not enough then, butorphanol can be administered at 1-2mg/kg to macaws.
• The maximum effect is observed within 7-10 minutes.
• Sedation makes physical examinations, radiographs, blood draws and wound care possible.
• Flumazenil is used for reversal at 0.05mg/kg IM or IN.

Anesthesia: Considerations

• Prior to anesthesia, several factors should be considered.
• These include the bird's health status and whether fasting is necessary.
• Analgesia and supportive care are important.
• Also consider the duration of the procedure.

Health Status

• Key factors in determining health and need for anesthesia include the animal's history and anamnesis should be known.
• It's important to observe the bird for dyspnea or diarrhea prior to exploration.
• The need to immobilize.
• Pre-anesthetic tests include hematology, biochemistry, minimum Hto, PT, frotis, and radiographic study.

Fasting

• The crop should be empty to prevent regurgitation, and aspiration if required.
• There is a low risk of hypoglycemia.
• Recommendations include fasting for psittacines (400-1000g) for 3/4 hours for long procedures, not necessary for short ones.
• Raptors should fast for 6-9 hours.

Analgesia

• Pain should get treated before it occurs; the number of studies regarding limitations is few, and there are limited results.
• Options include local anesthetics like lidocaine, bupivacaine, and benzocaine.
• Take caution of the toxic risk due to overdose.
• Avoid corticosteroids due to immunosuppression in birds.
• COX1/2, are used in meloxicam and carprofen.
• Psittacidae is a K>mu butorphanol receptor.
• Raptors/passeriformes are mu>k buprenorphine receptors.
• Butorphanol is now the more recommend anti- inflammatory treatment.

Anesthesia: Premedication

• Premedication results in smoother inductions and reduces induction dose and maintenance.
• Midazolam 1mg/kg + butorphanol 0.5-1 mg/kg is used for psittacidae.

Anesthesia: Induction

• Induction can be achieved through injectable or inhalant methods.
• Inhalant is indicated in most cases.
• Isoflurane/sevoflurane is used, sevoflurane is more rapid.
• Preoxygenation must occur, inductions should go from less to more and maintenance is at 2-3%.
• Intubation is required due to cranial glottis.
• ET tubes without a balloon because of complete tracheal rings
• Use a T-ayre circuit for animals under 5 kg.

Monitoring

• Monitoring involves several key aspects, most importantly temperature.
• Heat causes loss through convection by air around the animal, so it's suggested to cover patient and minimize feather removal.
• Conduction occurs through contact with a cold surface.
• Radiations caused by temperature differences between the animal and their environment need to be worked on within environments at room temperature with a heat source.
• Also keep in mind evaporation caused by respiration and exposure of organs, and keep hydrated anesthetic gases.

Monitoring aspects

• Ensure experienced personnel Pay attention to:
• Reflexes
• Doppler
• Pulse oximetry
• Capnography (if intubated)
• Temperature: preventing hypothermia.

Reflexes to monitor:

• Palpebral
• Corneal
• Withdrawal
• Cera
• Reaction to positional changes
• Mandibular tone
• Anesthetic Phase Reflexes

Phase 1

• All reflexes (palpebral, podal, cera), movement of the third eyelid.

Phase 2

• Loss of all reflexes.
• Is is common to see relaxation of the muscles, head dropping, slow breathing.
• Sometimes excitation stage

Phase 3

• There are no voluntary movements, but there are still reflexes.
• Respirations regulate, fast, and deep. There is some mandibular tone present, and doesn not respond to sounds.

Phase 4

• All reflexes and muscle relaxation are absent.
• Respirations are fast, deep, and slow with no tone in mandibular.
• The final and dangerous phase contains slow and shallow respiration with dilated pupils.

Anesthesia: Recovery phase

• Monitor the patient during recovery.
• Provide hydration, temperature, and food. Provide also analgesia.

Surgery

• For surgery, preparation and instrumentation is key.
• Betadine should be used instead of alcohol.
• Additionally, remove piumes but do not shave.

Surgical Principles

• The reduction of hemorrhaging and traumatization is important.
• The focus should be on reducing surgical time to avoid complications.
• Provide post-surgical and analgesia support.

Frequent surgeries of the soft tissue

• The doctor can perform some Ingluviotomía in order to make it possible to achieve some distinct aperture quirurgica del buce.
• Canulation of the air sack
• Selenotomy
• Surgery for reproduction
• Orthopedic repair
• Endoscopic method
• Sexing procedure

Surgery: Ingluviotomy

• Opening of the surgical crop
• Indications:
• Burns
• Foreign bodies.
• Do perform surgery because sometimes the part becrosada can be amplified.
• It's suggested to wait to assess to prevent leaving tissue no viable.
• It is useful to remove foreign items

Fistula from burns

• Intubate patient
• Remove necrotic tissue
• Clean well with diluted chlorhexidine
• Desbride axles of fistula to sepear wall from structures
• Separate the crop from the skin using some blunt dissection
• Close in 2 layers
• Invert the structure of a burn, creating a fistula that must be repaired using surgery. Fistucla should be closed.

Coeliotomy

• Opening of the surgical celioma.
• Indications are reproductive, or, removal of tumors, liver, kidney biopsy pancreas or gonads. Extraction can be used for organs as well.

Celiotomy lateral

• On the right side
• Access to the left celoma is available
• Can explore the proventriculo

Selenotomy medial-

• The surgeon accesses it in the middle or paramedial

Digestive Surgery

• To remove foreign bodies
• Enterotomy
• Enterectomy
• Magnification is needed

Most frequent surgeries are ovarian removal

• Indicators:
  • Neoplasia
  • Quiste persistence

Salpingohisterectomy

Orthopedic repairs

Resolution Prolapses

Endoscopy

• Utilized in birds, due to short recovery and minimally-invasive measures reducing the risk of patient stress. Useful for
• Diagnostics, such as sexing, biopsies, and sample-taking
• Therapeutics, such as removals of foreign objects
• Small and rigid instruments with diameters for inspection

Celioscopy

• It may be useful to find the estomago, or avoid the estomago from torsion. For example, for small issues you can do it in the celoaca as well, in order to prolapse.
• Used to observe inside and use it as a guide
• Entrances should start around the caudal to be more precise

Endoscopic Sexing

• Done mostly from the abdominal perspective
• Ovaries show many follicles and vascularity.

Theraputic Endoscopy:

• It's used to take some of the
  • Liver
  • Kidney
  • Bazo