Don t Panic! Dr. Karau s Guide to Respiratory Emergencies November 4, 2018
Objectives Oxygen delivery methods Emergent diagnostic tests Differentiating between upper and lower respiratory disease Respiratory lookalikes Case example
Goals of oxygen therapy? Fraction of inspired oxygen (FiO2) of room air is 21%. Goal of O2 therapy is to increase FiO2 to 40-50% in most cases Flow-by: 25-40% at 2-3 L/min. Can use higher flow rates, but patient may not tolerate the wind. O2 Cage: 40-50% Nasal O2: 30-70%. Flow rates over 100 ml/kg/min may cause discomfort Endotracheal intubation: 100%
Oxygen delivery methods Flow by oxygen +/- mask Simple, affordable Labor-intensive
Oxygen delivery methods Oxygen cage Hands-off management of stressed patients - cats! Plastic wrap will work in a pinch - leave a gap to let heat/humidity/co2 to escape. Need high O2 flow rates to maintain an oxygen -rich environment Size limitations
Oxygen delivery methods E-collar/oxygen tent Works well for large dogs that won t tolerate nasal oxygen or have contraindications such as coagulopathy. When using plastic wrap, leave approx 25% of the e-collar uncovered at the top to allow CO2 to escape.
DIY Oxygen cage and Oxygen Hood
Oxygen delivery methods Nasal oxygen catheters Ideal for medium to large dogs. Red rubber catheter, usually -10 5 fr. Apply proparacaine to the nares.will need to -apply re q 2-4 hours. Measure from the alar fold to the medial canthus. Insert into the naris, directing the tube ventromedial along the floor of the nasal cavity. Staple or suture using tape butterflies. Flow rates at 50-150 ml/kg/min.
Nasal Oxygen
Oxygen delivery methods Endotracheal intubation Severe laryngeal edema Respiratory arrest/near -arrest
Upper respiratory disease Disorders of the pharynx, larynx, and trachea Typically functional or mechanical obstruction Noisy! Stertor, stridor, cough Inspiratory dyspnea
Common causes of upper respiratory disease Dogs: brachycephalic airway syndrome, laryngeal paralysis, tracheal collapse, masses foreign objects, infections Cats: laryngeal masses, nasopharyngeal polyps, foreign objects, severe URI
Emergency management of upper airway disease Oxygen supplementation! Sedation Butorphanol - 0.1-0.4 mg/kg IM or IV +/- acepromazine 0.01-0.03 mg/kg IM or IV General anesthesia for endotracheal intubation and laryngeal exam Rapid induction agent: propofol or alfaxalone Diagnosis can often be obtained with sedated oral/laryngeal exam. Before intubating, pause to evaluate laryngeal function. IV fluids if hyperthermic or dehydrated IV steroids if significant laryngeal edema Anti-inflammatory dose of Dexamethasone SP - 0.15 mg/kg. Tracheostomy if intubation not possible
Complications of upper respiratory disease Hyperthermia/fever Laryngeal edema Secondary non-cardiogenic pulmonary edema Aspiration pneumonia ***Take thoracic radiographs after the pet is stabilized***
Lower respiratory disease Abnormal lung sounds Expiratory dyspnea - airway inflammation Paradoxical breathing Orthopnea Shallow breaths - pleural space disease History and signalment are important!
Common causes of lower respiratory disease Dogs: cardiogenic edema, bacterial or fungal pneumonia, hemorrhage, neoplasia, pulmonary hypertension, pulmonary thromboembolism, non-cardiogenic pulmonary edema, acute respiratory distress syndrome, pleural effusion, pneumothorax, diaphragmatic hernia
Common causes of lower respiratory disease Cats: cardiogenic edema, inflammatory airway disease, pleural effusion, non - cardiogenic pulmonary edema, acute respiratory distress syndrome, neoplasia, pneumonia, diaphragmatic hernia
Emergency management of lower respiratory disease Oxygen Light sedation - butorphanol at 0.1-0.4 mg/kg IM Furosemide for suspected CHF cases Dogs with murmurs, most cats 2-4 mg/kg IM TFAST - focused ultrasound Thoracocentesis Dull/absent lung sounds Ventral = fluid, dorsal = air Radiographs General anesthesia for endotracheal intubation and manual/mechanical ventilation
Respiratory Look-alikes Non-respiratory causes of increased respiratory rate and/or effort Compensation for metabolic acidosis Decreased oxygen content (anemia, methemoglobinemia, CO toxicosis) Pain/stress/anxiety Hyperthermia Electrolyte/metabolic imbalances (severe hypokalemia, hypoglycemia, hypocalcemia) Disorders of the peripheral or central nervous system Severe abdominal distension
Thoracocentesis Supplies Needles - butterfly or over-the-needle catheter. 20-22 ga for cats. 14-18 ga for dogs. Long catheters may be required for large dogs. 3-way stopcock Extension set - can skip if using a butterfly 12-60 cc syringe Clippers, scrub Red and purple-top tubes, collection vessel
Thoracocentesis Procedure Patient positioning: standing, sternal, or lateral recumbency (patient preference) Centesis site: 7th to 9th intercostal space, or ultrasound -guided Clip and aseptic prep Choose the upper ⅓ -½ of the thorax to tap a pneumothorax, the lower ⅓ to obtain fluid Avoid the caudal border of the rib when inserting the needle (bevel down). Advance the needle slowly until it pops through the pleura. If tapping fluid, you should see fluid in the needle hub. If using a catheter, remove the stylet and connect your extension set. If using a butterfly, direct the needle ventrally along the thoracic wall to avoid lacerating the lung.
Thoracocentesis sites Air Fluid
Tracheostomy Ventral midline incision starting at the cricoid cartilage, -32 cm After separating the sternohyoid muscles, make a horizontal incision between the 3rd and 4th or 4th and 5th tracheal cartilages. Incision should be <½ the circumference of the trachea Place long stay sutures around the cartilages adjacent to the incision. These are helpful during tube insertion and replacement. Tie tube in place.
Lower Respiratory Disease - Video https://photos.app.goo.gl/36heyyrrzeec9emu6
Joe Signalment and history: 3 year old MI GSD Progressive dyspnea over -54 days Physical exam Orthopnea, shallow respirations Auscultation: Absent lung sounds ventrally, mildly increased lung sounds dorsally Tachycardia with irregularly irregular rhythm and asynchronous pulses
Joe, continued Radiographs
Joe, continued Joe was ultimately diagnosed with atrial fibrillation and secondary CHF. He was treated with diuretics, pimobendan, and diltiazem. Joe was euthanized 5 months after diagnosis due to progressive clinical signs.
Questions?