Exam 2 Clinical Examples Flashcards
A 12 yr old Golden Retriever dog arrives in the ICU on a Friday afternoon. The dog has severe inspiratory dyspnea, cyanosis, and an exaggerated, labored thoracic and abdominal breathing pattern. A quick physical exam reveals a rectal temperature of 41.1 C, and stridor localized to the larynx. Laryngeal paralysis is suspected.
How will you initially stabilize this patient? Be specific.
Laryngeal paralysis is a type of upper airway obstruction, which is considered extrapulmonary. We want to bypass the obstruction to secure an open airway and provide O2 as needed. Sedate to decrease stress.
A 12 yr old Golden Retriever dog arrives in the ICU on a Friday afternoon. The dog has severe inspiratory dyspnea, cyanosis, and an exaggerated, labored thoracic and abdominal breathing pattern. A quick physical exam reveals a rectal temperature of 41.1 C, and stridor localized to the larynx. Laryngeal paralysis is suspected. After initial attempts to stabilize the dog, soft tissue surgery service decides to do a laryngeal exam followed by placing a laryngeal suture prosthesis to abduct one of the arytenoid cartilages.
a. What is your choice of premedication agent? Why?
b. What is your choice of induction agent? Why?
c. What is your choice of maintenance agent? Why? d. What is your choice of postoperative analgesic? Why?
a. Acepromazine, it calms them down and allows them to breathe easier.
b. Light level of propofol. Can sometimes use doxapram during laryngeal exam to stimulate respiration.
c. Iso, keep at lowest MAC to limit respiratory depression.
d. NSAIDs to decrease swelling
Oncology service presents you with a 14 yr old mixed breed dog for diagnostic workup prior to placing on hyperfractionated radiation therapy (ie. multiple daily doses of XRT so that the total radiation dose can be higher without excessive normal tissue toxicity). Lung metastases are noted on the awake chest radiographs. What effect, if any, will lung metastases have on your anesthetic plan?
These will inhibit gas exchange within the lung locally where they have metastasized so we will increase fraction of inspired oxygen
- During anesthesia for shoulder arthroscopy, a 450 kg standardbred horse is noted to be difficult to keep anesthetized, requiring a higher than expected vaporizer setting. An arterial blood gas is drawn. FIO2 is 100%, and the horse is being mechanically ventilated with a tidal volume of 7 L, frequency of 6 breaths/min, and a peak inspiratory pressure of 25 cm H20.
pH: 7.35
pO2: 63 mmHg
pCO2: 43 mmHg
HCO3: 26 mEq
What is likely happening here? What can you, as the anesthetist, do to resolve this problem?
The horse is hypoxic because pO2 is less than 80 mmHg (he is close to severely hypoxic, which is <60 mmHg)
We fix this by combating the hypoxia.
A puppy with cleft palate has aspiration pneumonia but has to be anesthetized anyway. What can you do to optimize its respiratory status during the anesthetic period? Be specific
Intubate with ET tube to ensure oxygen flow. Pneumonia is a parenchymal pulmonary dz so he has a low PaO2, low V/Q ratio. We fix this by increasing FiO2 (increasing FiO2 should increase PaO2 and allow for a normal V/Q ratio).
You are the anesthetist for an 11 yr old cat undergoing computed tomography (CT) of a mass in the lower lumbar region. The cat is placed on a mechanical ventilator in the CT suite and no problems are noted during the procedure.
During recovery from anesthesia, you notice that the cat has dusky mucous membranes and tongue color even though the cat is still on oxygen and is intubated. Spontaneous respiratory efforts by the cat are mainly abdominal and labored, with little movement of the reservoir bag on the non-rebreathing circuit. When you assist ventilation, the cat’s color improves to a nice healthy pink color, but when you stop, the labored abdominal breathing pattern returns, and the color deteriorates over the next few minutes.
a. What do you suppose is going on here? What physical examination techniques could you use in the recovery area to aid in your diagnostic rule out?
b. What is your tentative diagnosis? How could you definitively confirm this diagnosis?
c. What is your treatment?
a. Cat cannot breathe on its own, baroreceptor trauma induced pneumothorax. We can do a thoracic auscultation- muffled sound.
b. Pneumothorax. Confirm with radiographs.
c. Butterfly needle under skin over the top of one or two ribs into pleural space. Hook up syringe and pull air out until its gone.
It is a typical day in Mississippi in late July. The VTH air conditioning is out of order, and the temperature in the OR’s is approaching 90 F. A Huskie/Shepard mixed breed dog is undergoing a radial fracture repair under several heavy drapes. The anesthesia student notices the dog is panting heavily and the heart rate is increasing.The blood pressure is stable, there are no eye reflexes, jaw tone is nonexistant, and there is no purposeful response to surgical stimuli. The circulating water heating blanket is noted to be on.
a. How will you make the definitive diagnosis?
b. How will you treat this animal?
a. Take a rectal temperature
b. For hyperthermia, we want to decrease temperature by surface cooling methods. Water is more effective than alcohol because it does not cause vasoconstriction (alcohol causes vasoconstriction and limits heat loss). You can put a bag of ice over suitable skin area
A 4kg dachshund dog is anesthetized for a myelogram prior to a hemilaminectomy. After 2 hrs in radiology, the heart rate has fallen to 49 beats/min, and multiple doses of glycopyrolate have had no effect.
a. How will you make the definitive diagnosis?
b. How will you treat this animal?
a. Take a rectal temperature
b. For hypothermia, give him a bair hugger, warm water blanket, heater, warm lavage fluids, shorten anesthesia time, etc.
Glycopyrrolate likely not working because it is inactive at lower temperatures.
A miniature schnauzer dog arrives in ICU on the same July day as in question 1. It was locked it in a closed car for 30 min while its owner was running some errands. The dog is unconscious and has a weak, rapid pulse.
a. How will you make the definitive diagnosis?
b. How will you treat this animal?
a. Take a rectal temp
b. Hyperthermia. Put water on pads of feet (more effective than alcohol). Surface cooling is more effective than lavage or cold-water enemas.
Do this gradually to avoid shock or cardiac rhythm disturbances.
- You are responsible for providing anesthesia for a dog undergoing surgical repair of a tetralogy of Fallot. Since we don’t have a cardiac bypass machine, surface hypothermia is the method of choice to induce deep hypothermia to a core temperature of 20C in order to preserve brain function during the 30 min of complete cardiac arrest necessary to make the repair.
a. How much isoflurane anesthesia will be needed to anesthetize this dog at a body temperature of 20C?
b. A turtle blood gas is taken at 20C. The temperature corrected value (corrected to the patient temperature at time of sampling) for pH is noted to be 7.8 and the pCO2 is 18 mmHg. Is the turtle hyperventilated?
c. The muscle relaxant atracurium was used to provide skeletal muscle relaxation. Would you expect the duration of action to be increased, decreased, or remain the same at 20C?
a. MAC decreases 5% for each degree under 37 C- so it would decrease 17x5= 85%. So we only need 15% of normal MAC iso to keep patient anesthetized.
b. Yes, turtle is hyperventilated (low pCO2- we want pCO2 around 35-40 mmHg. He also has increased pH). We can say this because the temperature corrected value lets us interpret all blood gases at 37⁰ C, it gives us a common basis to make comparisons using familiar values. The decrease in pCO2 shows us that too much CO2 is being blown off- loss of acid leads to basic blood pH.
c. Actracuriam inactivation is decreased at lower temperatures, so it increases duration of action
