What are some potential clinical signs you might see with anaphylaxis or anaphylactoid reactions?
- CV: hypotension, cardiac arrest/collapse, tachycardia, arrhythmias
- Resp: cyanosis or hypoxemia, labored breathing, bronchospasm, laryngeal edema
- Cutaneous: uticarial rash (small localized or large edematous), hypermia of skin, thickening of lips/eyelids/skin folds
- Others: muscle rigidity or flaccidity, defecation
What should you use if trying to anesthetize a cat with complete laryngospasm?
Administer succinylcholine IV and initiate IPPV
What should you administer if a patient has a known high risk of reactions to anesthetic agents?
- Dexamethasoneor prednisolone sodium succinate and diphenhydramine
What are some situations in which a relative anesthetic overdose might happen?
- Patients with reduced anesthetic requirements: geriatric, advance pregnancy, hypoT4, patients w/ CNS depression, Addison’s, debilitated patients
- patients w/ reduced volume of redistribution: hypovolemia, obesity
- altered ionization or hypoproteinemia
What are some special considerations that you should have for patients that had vomiting as a clinical finding?
- Glycopyrrolate to decrease acidity
- Cimetidine to decrease gastric acid secretion
- Metoclopramide and famotidine to minimize regurg
- Rapid sequence induction
- Cricoid pressure while intubating
- Cuff deflation and extubation only once patient has regained the protective airway reflexes
Malignant hyperthermia always results in what two things?
High increases in PaCO2 and severe metabolic acidosis
What are some things that can cause anaphylaxis or anaphylactoid reactions?
- Anesthetic drugs: thiopental, thiamylal, atropine, morphine, meperidine, tubocurarine, procaine, xylazine
- antibiotics: penicillin
- plasma, blood, Dextran
- iodinated contrast material
Why is there still an aspiration risk even if you pre-med with an antiemetic, atropine or glycopyrrolate followed by ace?
Because they reduce the incidence of vomiting but not regurgitation
What should you do in the case of a barbiturate overdose?
Administer sodium bicarbonate —> will alter blood pH and ionization of the drug, resulting in nonionized (inactive) form
What are various causes for vomiting or regurgitation in an anesthetic patient?
Drugs causing relaxation of esophageal sphincters: atropine, ace, xylazine
Drugs stimulating the vomiting centers: morphine, hydromorphone, xylazine
Why might cyanosis be difficult to detect in an anemic patient?
Because cyanosis is a function of hemoglobin and oxygen concentration
How do you manage anaphylaxis or an anaphylactoid reaction in an anesthetic patient?
- Stop administration of causative agents, and anesthetic agents if severe hypotension present
- intubate and oxygenate if not already done, otherwise inhalants will counteract bronchospasm
- adminstered crystalloid boluses
- give Epi IV(0.01 mg/kg), H1 blocker (diphenhydramine) IM, aminophylline (if bronchospasm present), and corticosteroids
What are the clinical signs of giving a perivascular injection?
- Pain during injection
- Inappropriate response to the dose of an anesthetic administered
- Obvious swelling at injection site
- Slight resistance when injecting and agent into an indwelling IV catheter that is out of the vein
What is the difference between anaphylaxis and an anaphylactoid reaction?
- Anaphylaxis - reaction involves antigen and IgE antibodies; previous sensitization to antigen is required
- Anaphylactoid reaction - reaction mediated by histamine; previous sensitization to antigen not required and can happen even with first exposure
If MH is strongly suspected, what steps should be taken?
- Discontinue inhalant immediately
- ventilate 100% oxygen using different machine
- administer dantrolene (decr Ca released —> reduced contraction of sk mm)
- administer sodium bicarbonate
- cooling mechanisms
What is the difference between an absolute and relative overdose?
- Absolute: dose or concentration of anesthetic substantially greater than desired
- Relative; desired dose or concentration of anesthetic causes cardiopulmonary compromise
What are some reasons an anesthetic patient might be experiencing tachypnea?
- Use of opioids: morphine, meperidine, hydro (reset thermoregulatory mechanism)
- Hypercarbia from equipment failure
- Light anesthesia
- Hyperthermia: malignant hyperthermia, hypermetabolic state (sepsis), excessive application of outside heat
How do you manage/treat giving a perivasular injection?
- Infiltrate tissues w/ saline until moderately distended
- If thiopental or thiamylal —> SQ lidocaine (w/o epi) up to 2 mg/kg PLUS saline
- Frequently apply hot pack
- DMSO gel topically q12h x 3d (anecdotal)
What are 4 agents that may cause tissue irritation if given perivascularly?
- Thiopental
- Thiamylal
- 20-50% dextrose
- Sodium bicarbonate
What are the clinical signs of an anesthetic overdose?
- Respiratory arrest or profound resp depression
- Fixed and dilated pupil
- Severe hypotension
- Bradycardia
- PEA or cardiac arrest
Describe malignant hyperthermia
- Genetic condition - defect in cell membrane of skeletal muscle
- triggered by stress or a drug
- Uncontrollable elevation in myoplasmic Ca resulting in hypermetabolism and muscle contraction —->increased heat production
- Most episodes associated w/ halothane
- temp elevaion is often late sign of MH
What are the clinical signs of endobronchial intubation?
- changes in oxygenation: either decreased O2 saturation (shunting) or remains the same with FiO2 of 100%
- decreased breath sounds on non-ventilated side
- uneven chest movement with controlled ventilation
- increased peak insp pressure with mechanical ventilation
- end tidal CO2 behavior is unpredictable
How should you proceed if your patient has pulmonary edema?
- Intubate and supply 100% oxygen
- Control ventilation
- apply PEEP
- administer furosemide, morphine, and dobutamine or dopamine, if there’s hypotension
