Crisis Scenarios Flashcards
What process occurs to cause a bronchospasm?
Reflex Bronchiolar Constriction
What are the two mechanisms in which bronchospasms occur?
Centrally mediated
Local reaction
What two things occur in a bronchospasm that would cause air trapping and hyperinflation?
Constriction
Mucus hyper secretion
What complication could occur from excessive air trapping after a bronchospasm has occurred?
May result in pneumothorax
How would a bronchospasm eventually lead to cardiac collapse?
Alveolar distention increases intrathoracic pressure
Decreased venous return and cardiac output
Results in cardiac collapse
What are the causes of a bronchospasm?
Airway Manipulation Noxious Stimuli Cold Air Airway Irritants Acute Exposure to Allergens Stress of Surgery Histamine Releasing Medications (morphine, vancomycin, atracurium)
What other pathologies should be ruled out from wheezing?
Pneumothorax, endotracheal tube obstruction, anaphylaxis, pulmonary edema, pulmonary aspiration
What are the signs of a bronchospasm that an anesthetic provider may see?
Mucus Hyper secretion
High inspiratory pressures
Blunted expiratory CO2 waveform
Hypoxemia
How might an awake patient present with a bronchospasm?
Tachypnea & Dyspnea
What can wheezing tell us about a bronchospasm?
Degree of wheezing is a poor indicator of the extent of obstruction
What is the immediate treatment for a bronchospasm in the OR setting?
Check endotracheal tube position for carinal stimulation
Deepen the level of anesthetic, volatile agents are usually sufficient, if ventilation impaired, use IV sedative
Increase FiO2 to 100%
Administer a short-acting β2-agonist
What are some additional treatments for a bronchospasm if unable to relax the tissue?
Administer IV/IM epinephrine (10 mcg/kg)
Administer IV corticosteroids (Hyrdrocortisone 2-4 mg/kg)
Consider IV aminophylline if long term mechanical ventilation is planned
When does negative pressure pulmonary edema occur?
Usually occurs during emergence
What two events usually cause negative pressure pulmonary edema?
Result of two events:
Airway obstruction
Patient initiated forceful breath
What type of pulmonary edema is experienced by patients with negative pressure pulmonary edema?
Non-cardiogenic
What physiologic process occurs with negative pressure pulmonary edema?
Forceful inhalation attempt against a “closed glottis” creates extreme negative intrapleural pressure
Increased pulmonary transcapillary hydrostatic pressure
Rapid movement of fluid into lung interstitium, pulmonary lymphatic system overwhelmed
What is the primary cause of NPPE?
Laryngospasm
What other processes can also contribute to causing NPPE?
Airway Obstruction
Forceful inhalation
What other forms of pulmonary edema should be ruled out when considering NPPE?
Congestive heart failure & fluid overload
Acute respiratory distress syndrome
Aspirate gastric contents
How does NPPE present once the laryngospasm has resolved?
Bilateral rales heard on auscultation
Rapid onset
May progress to hypoxemia
What is a late sign of NPPE?
Frothy, pink sputum or frank bloody secretions indicate alveolar injury
What is the most important components in treating NPPE?
Quick recognition is critical (vigilance) critical to treat before hypoxia and alveolar injury
What is the typical treatment for NPPE?
Identify and resolve airway obstruction Supportive Therapies, oxygen & CPAP May require (re)intubation for mechanical ventilator support
What medications may be used to treat symptoms related to NPPE?
Consider steroids to stabilize capillary membranes
Important! – Diuretics are not always indicated
What is the typical treatment for NPPE?
Identify and resolve airway obstruction Supportive Therapies, oxygen & CPAP May require (re)intubation for mechanical ventilator support
What is pulmonary aspiration?
Misdirection of oropharyngeal or gastric contents into the larynx and lower respiratory tract.
What is another name for Aspiration Pneumonitis?
Mendelson’s syndrome
How does an infection occur after aspiration if the fluid is acidic?
Acid aspiration pneumonitis reduces host defenses, increasing the risk of superinfection
Infection develops if aspirated material is colonized with bacteria, or when airway burns allow infection to develop from commensal pathogens.
What determines the severity of aspiration pneumonitis?
Varies directly with the volume of aspirate & indirectly with its pH.
When is aspiration most likely to occur?
Largest number of aspirations occur during induction and emergence.
How is aspiration diagnosed?
Visualization of gastric content in ET tube
ABG results
Infiltrates in perihilar and dependent regions with pulmonary edema
What is the hallmark sign of intraoperative aspiration?
Arterial hypoxemia
What actions should be taken if a patient vomits during induction?
Turn paFent’s head to the side, put bed in trendelenburg
Suction mouth and pharynx
Intubate using RSI as soon as possible
Perform tracheal suctioning and check pH of aspirate
What actions should be taken if a patient vomits during induction?
Turn patient’s head to the side, put bed in trendelenburg
Suction mouth and pharynx
Intubate using RSI as soon as possible
Perform tracheal suctioning and check pH of aspirate
What treatment should a patient receive if aspiration occurs?
Supportive Treatment
Oxygenation to minimal extent necessary
Aspiration of caustc material can increase likelihood of O2 toxicity
PEEP (after suctioning!) to treat/prevent atelectasis • Bronchodilators
• Empirical antibiotic/steroid treatment is discouraged
What are the functions of the laryngeal muscles?
Swallowing
Breathing
Coughing
Speech
What is the purpose of the laryngeal adductor reflex?
Essential reflex
• Allows swallowing without aspiration
• Protects lower airway
• Medullar mediation
What is a laryngospasm?
A prolonged and intense exaggeration of the glottic closure reflex
Mediated through vagal stimulation of the superior laryngeal nerve
What are patient specific risk factors for a laryngospasm?
Patient factors: • Hypocalcemia • Hypoparathyroidism • Reactive airway disease • Airway trauma
What procedures can predispose a patient to a laryngospasm?
Parathyroid surgery
Septoplasty or rhinoplasty surgery
What population is at a higher risk for laryngospasm?
Pediatrics
What risk factors are associated with laryngospasm?
Recent or current URI
Exposure to secondhand tobacco smoke
GERD
Oropharyngeal secretions
What two conditions must be present for a laryngospasm to occur?
Noxious stimuli
Inadequate anesthetic depth (stage II)
What drugs can be administered to prevent a laryngospasm for occurring?
IV lidocaine
Topical lidocaine
IV magnesium
Deep extubation
What is Larson’s maneuver?
Forceful jaw thrust with bilateral digital pressure on body of mandible, anterior to mastoid process
What dose of succinylcholine should be given initially to a patient with a laryngospasm?
0.1 -0.5mg/kg, usually 10-20mg
If a small dose of succinylcholine does not break the spasm can an additional dose be given?
Use intubating dose (1-1.5mg/kg) followed with tracheal intubation
If the anesthetic provider is unable to intubate the patient what should be done?
Perform percutaneous airway
When does a type I allergic reaction occur?
Occurs in those previously exposed and sensitized
The antigen joins IgE antibodies to mast cells or basal cells
Histamine is released acting on H1 or H2 receptors
What causes a type II allergic reaction to occur?
IgG and IgM antibodies!
What is a type III allergic reaction?
Immune complex disease, antigen- antibody complex causes tissue damage
What is a type IV allergic reactions?
Delayed-type hypersensitivity
What is an anaphylactoid reaction?
Caused by mediator release from basophils and mast cells in response to a non-IgE-mediated triggering event!
What receptors does histamine agonize and what are their functions?
H1: vasodilation, bronchoconstriction, increased vascular permeability
H2: cardiac stimulation, stimulation of gastric secretion
What are the top six causes of anaphylaxis in the medical field?
NMB: 69.2% Latex: 12% ABX: 8% Colloids: 2.3% Opioids: 2.2% Hypnotics: 1.1%
What two NMBA are most likely to cause an anaphylactic reaction?
Succinylcholine and rocuronium are responsible for the highest frequency of allergic reactions
What type of allergic reactions can be seen with latex use?
Type I or Type IV hypersensitivity reaction
What populations are at risk for latex allergies?
Healthcare workers
Multiple surgeries
Congenital NTDs
Fruit allergies to avocado, banana, and kiwi!
What drug is known to cause majority of the fatal drug reactions that can occur?
Penicillin allergy accounts for 75% of the most fatal anaphylactic drug reactions
What are the three types of transfusion reactions?
Febrile: caused by the interaction between recipient’s antibodies and antigens present on leukocytes or platelets of the donor
Allergic: reaction to properly typed and cross- matched blood
Hemolytic: reaction to wrong blood type causing intravascular hemolysis
What immediate steps should be taken if intraoperative anaphylaxis is suspected?
Stop the infusion/remove the allergen
Administer Epinephrine!
Manage ABC: Maintain airway and administer 100% oxygen
What fluids can be given to help with the hypotensive effects of anaphylaxis?
NS: 10-25 ml/kg for 20 minutes; total of 2-4 L
Colloid: 10 ml/kg
How does epinephrine help an anaphylactic reaction?
Stabilizes mast cells, Alpha 1 effects support BP, Beta 2 effects produce array smooth muscle relaxation
How do antihistamines help an anaphylactic reaction?
May reverse hypotension refractory to EPI and fluids; particularly useful for uticaria and
angioedema
How should an anaphylactic reaction be immediately investigated?
Circulatory serum tryptase (predominant mast cell protease), plasma histamine, specific IgE assays: high circulating levels strongly suggest an immunological reaction
What follow up precautions should a patient with an anaphylactic reaction take?
Skin tests should be carried out 4-6 weeks after the reaction
Should be performed with all drugs used during anesthesia, excluding inhalation agents
What signs are typically the first to be recognized in an anaphylactic reaction?
Bronchospasm and circulatory collapse are the first recognized signs of anaphylaxis
What gender is more likely to experience anaphylaxis?
Females
What individuals are at an increased risk for allergy to propofol and latex?
Atopic individuals with increased IgE
What precautions should be taken in the OR if a patient has a latex allergy?
For patients with a latex allergy in non-latex free environments, the patient should be scheduled first in the OR since latex allergens remain airborne.
