Respiratory Disease Anesthesia Flashcards
what are the goals of anesthetic management of animals with respiratory disease?
- minimize stress
- pre-oxygenate
- intubate rapidly
- ventilate
- monitor closely into and during recovery
what are the primary components of BOAS? what do they cause? (5)
- elongated and thickened soft palate
- stenotic nares
- hypoplastic trachea
- aberrant turbinates
- relative microglossia/redundant pharyngeal tissue
the primary components and congenital and cause negative pressure during inspiration which leads to the secondary characteristics of BOAS
what are the secondary characteristics of BOAS? (7)
caused by the negative pressure during inspiration from the primary components
- everted laryngeal saccules (grade I laryngeal collapse)
- laryngeal collapse (progressive; grade II and III)
- bronchial collapse
- everted tonsils
- pharyngeal/laryngeal edema
- esophagitis/regurgitation/aspiration
- cor pulmonale (R sided heart failure due to increase in pulmonary pressure)
describe preparation and induction of a patient with BOAS
- minimize stress:
-trazodone and gabapentin PO before drop off
-butorphenol +/- acepromazine IV PRN
-cool them down if hot - after pre-meds watch them closely!
- pre-oxygenate: increase O2 in functional residual capacity, buys you more time before they stop breathing
- have suction ready
- have a wide selection of cuffed ETs available (hypoplastic tracheas!!)
- give corticosteroids IV prior to surgery to minimize laryngeal swelling (NO NSAIDS)
- oxygen insufflation during laryngeal exam: attach oxygen tube to laryngoscope to provide oxygen without intubation
-for all animals, not just brachycephalics! - intubate rapidly: propofol, alfaxolone
-induce anesthesia rapidly but do cause apnea! - use GI drugs: before induction!
-prokinetics: metaclopramide
-gastroprotectants: famotidine or omeprazole
-antiemetics: maropitant or ondansetron
describe the caudal maxillary block; give 3 approaches
blocks maxillary nerve to block maxilla, soft palate, and tonsils
- maxillary tuberosity or intraoral approach
- subzygomatic or transcutaneous approach
- infraorbital approach
describe recovery of a BOAS patient
- ETT in place until dog is alert, may need to reverse drugs if possible
- monitor closely for hours to ensure airway obstruction does not occur
-very common to swell after tube removed!! - signs of obstruction:
-exaggerated airway movements without obvious air movement
-cyanosis
-mental distress
-too quiet - be prepared to re-anesthetize and re-intubate or do tracheostomy
-keep an ETT on cage door
describe treatment of/care for laryngeal paralysis patients
- in older larger breed dogs, a tie back surgery is performed
- this condition can cause partial or complete airway obstruction
-tranquilizer (acepromazine) + oxygen will minimize stress - monitor very closely
-general anesthesia might be needed urgently - IV anesthesia to do laryngeal exam
-propofol or alfaxolone better for laryngeal exam (propofol does snot affect arytenoid movement much once they start breathing again)
-may need doxapram to assess laryngeal function (stimulates another breath) - anti-inflammatory corticosteroids
-NO NSAIDS ON BOARD
describe management of laryngeal paralysis patients
- avoid full mu agonists
-increased risk of regurgitation and aspiration - sedation:
-acepromazine + dexmedetomidine (low doses) +/- butorphenol - induction:
-propofol or alfaxolone better for laryngeal exam
-may need doxapram to assess laryngeal function - analgesia:
-lidocaine CRI, ketamine CRI, butorphenol if needed
-anti-inflammatory corticosteroids (make sure no NSAIDs on board) - regurgitation intra-op and at extubation a possibility and huge problem!!!
-use metoclopramide and maropitant
describe rhinoscopy and rhinotomy
- obstruction can be unilateral or bilateral
-possibly with open mouth breathing
-cats can present with severe symptoms - main anesthetic concerns:
-pain: use full mu agonist opioids, ketamine, dexmedetomidine (when indicated), and local blocks
-blood loss: monitor and use blood product when necessary
-aspiration: ETT with cuff (good seal) + pharyngeal gauze packs (remove before extubation)
-post-procedural obstruction: monitor and intervene promptly
- caudal maxillary block!
describe common causes of intrapulmonary disease (4)
- infectious diseases
-bacteria, viral, fungal pneumonia - inflammatory disease
-chronic bronchitis, canine eosinophilic bronchopneumopathy, feline asthma - neoplastic disease
-primary pulmonary tumors and metastatic disease - miscellaneous diseases
-traumatic (lung contusion)
-pulmonary thromboembolism
-cardiogenic and non-cardiogenic pulmonary edema
describe treatment and management of intrapulmonary disease patients (5)
- may need general anesthesia
-for diagnostic procedures (bronchoscopy and bronchoalveolar lavage)
-unrelated to intrapulmonary disease (ex. has pneumonia but also has a foreign body) - minimize stress
- provide O2 flow-by before induction
- best to secure the airway quickly
-propofol or alfaxolone for induction - maintenance:
-inhalants: may not be able to use like with normal or upper airway disease patients
-injectable: propofol or alfaxolone CRI
–for bronchoscopy in small dogs and cats (if ET tube is too small for the endoscope to fit through and have to remove ET tube)
–for bronchoalveolar lavage
-if using injectable, we usually start them on it right away instead of starting on inhalant and then switching to injectables
describe causes of extraparenchymal pulmonary disease (4)
- pleural space:
-pleural effusion
-pneumothorax - chest wall:
-traumatic (flail chest, rib fracture)
-neoplasia - diaphragmatic hernia
- obesity and abdominal (organ) distension
- neurologic dysfunction
describe management of pneumothorax and pleural effusion patients
- thoracocentesis to remove air or fluid prior to anesthesia!!
-help them breathe and oxygenate better, and also to help make diagnostic imaging more clear and interpretable
-keep sternal! ventilate them!
method:
1. sedation to minimize stress
-butorphenol IM +/- low dose of dexmedetomidine if necessary
- place IV catheter for administration of more drugs and for emergency
- can be performed under general anesthesia but before the surgical/diagnostic procedure
- chest tubes if there is significant amount of air or fluid
describe recovery of pneumothorax patients
- continuous oxygen therapy
-flow by oxygen cage
-nasal cannula
-high flow nasal cannula: high flow warm air - monitoring:
-reflecting SpO2 probes
-for respiratory distress - pain management: opioids and ketamine
- sedation when indicated to reduce stress
-acepromazine, dexmedetomidine, gabapentin
describe anesthetic management of diaphragmatic hernia
- pre-anesthetic considerations
-provide oxygen therapy
-minimize stress
-place the patient in an upright or sternal position to improve ventilation
-perform thoracocentesis if indicated
-can be acute or chronic; acute is better for anesthesia, chronic may have more adhesions and release free radicals once those adhesions are released
- sedation:
-opioids
-benzodiazepines - +/- alfaxolone
- +/- low dose dexmedetomidine if cardiovascularly
- anesthesia:
-monitoring before inductions if possible
-plan ahead for complications: have emergency drugs calculated and ready
-induction:
–rapid sequence induction: secure airway quickly
–use controlled ventilation: to maximize lung expansion and gas exchange, necessary for thoracotomies
–remember!!: for these patients, if you open the abdomen you are also opening the chest (they communicate through the hernia hole), so provide ventilation!!!
-maintenance: inhalants, can tilt the table (head up) to release some of the compression caused by the herniated organs
