Complications Flashcards
What is considered perioperative mortality?
Death that occurs within 48 hrs of surgery
Current rate of anesthesia related death is 1 per 100,000 anesthetics
*prior to 80s death rate significantly higher
Goals of the ASA closed claims project
- identify major areas of loss in anesthesia
- identity patterns of injury
- identity strategies for prevention
Difference between preventable vs unpreventable anesthetic mishaps
Unpreventable
- sudden death syndrome
- fatal idiosyncratic drug reactions
- poor outcomes despite proper mgmt
Preventable
- human error
- equipment malfunction
Top 3 ASA closed claims in the 1990s
Death: 22%
Nerve injury: 18%
Brain damage: 9%
*% of law suits
What are emerging claims areas?
Regional anesthesia: 16%
Chronic pain mgmt: 18%
Acute pain: 9%
What are some human errors that lead to preventable anesthetic accidents?
- unrecognized breathing circuit disconnect
- medication errors
- airway mgmt (not preparing)
- anesthesia machine misuse (too big volumes, too little anesthetic)
- fluid mgmt
- IV line disconnection
What are some example of equipment malfunctions that lead to preventable anesthetic accidents?
- breathing circuit
- monitoring device
- ventilator
- anesthesia machine
- laryngoscope
Some factors associated with human error and equipment misuse
- inadequate preparation
- inadequate experience or training
- environmental limitations (ie inability to visualize surgical field, poor communication with surgeon)
- physical and emotional factors (fatigue)
Improvements that have helped prevent anesthetic complications
- improved pt monitoring
- improved anesthetic techniques
- improved education of anesthesia providers
- comprehensive protocols
- active risk mgmt programs
*focus on pt safety is the most important factor that has improved safety
Examples of complications of anesthesia
- airway injury (sore throat)
- peripheral nerve injury
- awareness
- eye injury
- cardiopulmonary arrest during spinal anesthesia
- hearing loss
- allergic reactions
Examples of types of airway injury
Sore throat Dysphasia Dental injury TMJ (risk of locked jaw) Vocal cord paralysis Vocal cord granuloma (typically with long intubation) Arytenoid dislocation Esophageal perforation
Complications related to positioning
Peripheral nerve injury
Hypotension
Incidence of anesthesia awareness
0.2-0.4% in most studies
When awareness does occur, pt may exhibit what symptoms
Mild anxiety Sleep disturbance Nightmares Post-traumatic stress disorder Social difficulties
Types of surgeries most associated with awareness
Major traumas: 43%
Obstetrics: 1.5%
Cardiac surgery: 0.4%
*in many instances awareness is related to the depth of anesthesia that can be tolerated
Ways to prevent intraoperative recall
- use inhaled agents at a level consistent with amnesia
- MAC 0.6 when used with opioids and N2O
- MAC 0.8-1.0 when used alone
- add benzo or IV scopolamine
- BIS monitor if available
*IV scopolamine has retrograde amnesia affects
How to treat pt that has had intraoperative awareness
- obtain detailed account of the pts experience
- by sympathetic
- answer pt questions
- refer pt for psychological counseling if appropriate
Types of eye injury
- corneal abrasion: most common and transient eye injury
- Blindess
- pt movement during ophthalmic surgery
- during general or MAC anesthesia
- ischemic optic neuropathy (ION)
- most common cause of posts-op loss of vision
- optical nerve infarction due to decrease O2 delivery via one or more arteriole supplying the optic nerve
Ischemic Optic Neuropathy is commonly reported after these surgeries
Cardiopulmonary bypass
Radical neck dissection
Abdominal and hip procedures
Prone spinal surgeries
Pt factors that contribute to ION
HTN
DM
CAD
Smoking
Surgical and anesthetic factors that contribute to ION
- Intra-op deliberate hypotension
- anemia
- prolonged surgical time in position that compromises venous outflow
- prone
- head down
- compressed ABD
Symptoms of ION
- range from decreased visual acuity to complete blindness
- onset immediately and through 12th post-op day
How to prevent ION
- enhance venous outflow by positioning the pt head up
- minimize ABD constriction
- monitor BP carefully with a-line
- lipid degree and duration of deliberate hypotension
- avoid anemia in pts at risk for ION
- consider staging long surgical procedures in pts at risk for ION
Some fun facts about cardiopulmonary arrest during spinal anesthesia based on closed claims case analysis of 14 pts
-average age: 36
-ASA: 1-2
-high level of block prior to arrest (T4 level)
-
Signs and symptoms prior to arrest during spinal anesthesia
- gradual decline in HR and BP (20% below baseline values)
- bradycardia
- hypotension
- cyanosis
Treatment for arrest after spinal anesthesia
- ventilatory support
- ephedrine
- atropine
- epinephrine
- do no hesitate to use epi in small doses (5-10mg) for bradycardia that is unresponsive to atropine and ephedrine. Use larger doses if necessary
- CPR (average duration 11 min)
- once arrest occurs begin ACLS protocols and doses
Cause of hearing loss after spinal anesthesia and treatment
- due to CSF leak
- Rx with blood patch
Causes of hearing loss after GA
- less predictable
- surgical manipulation
- middle ear barotrauama
- vascular injury
- ototoxicity of drugs
- s/p cardiopulmonary bypass
Common documentation errors to avoid
- completing entries for events before they occur
- incomplete descriptions of procedures or mgnt
- inaccurate of conflicting times between records
- loss of critical pt data
- signing documents without reading them
- failure to document meetings with the pt or family
- failure to obtain supporting documentation from others
These are exaggerated immunologic responses to antigenic stimulation in a previously sensitized individual
Allergic reactions
The allergen or antigen is typically what type of molecule that is covalently bound to a carrier protein
Protein, polypeptide, or smaller molecule
Ways in which a pt is exposed to allergens
Nose, lungs, eyes, skin, GI tract, IV injection
T/F: anaphylactic reaction can happen after the first exposure to a substance
False
First response triggers production of IgE antibodies. After subsequent exposure to same antigen, mast cells release histamine and others mediators
What are the 4 types of hypersensitivity reactions?
Type I: immediate
Type II: Cytotoxic
Type III: immune complex
Type IV: delayed, cell-mediated
What is Type I allergic reaction?
Immediate
- major type of reaction
- atropy
- urticaria - angioedema
- anaphylaxis
What is type II allergic reaction?
Cytotoxic
- hemolytic transfusion reactions
- autoimmune hemolytic anemia
- heparin-induced thrombocytopenia
What is type III allergic reaction
Immune complex
Allergies????
What is Type IV allergic reaction
Delayed, cell-mediated
-contact dermatitis
Anaphylaxis characteristically presents as:
Acute respiratory distress,
Circulatory shock, or both
Incidence of anaphylactic reactions during anesthesia
1:5000 - 1: 25:000 anesthetics
Mediators of anaphylaxis
Histamine
Leukotrienes
BK-A
Platelet activating factor
Cardiovascular manifestations of anaphylaxis
Hypotension, tachycardia, arrhythmias
Pulmonary manifestations of anaphylaxis
Bronchospasm, cough, dyspnea, pulmonary edema, laryngeal edema, hypoxia
Dermatologic manifestations of anaphylaxis
Urticaria, facial edema, pruritus
Anaphylactoid reactions
Resembles anaphylaxis but does not depend on IgE antibody interaction with antigen.
How do you tell the difference between anaphylaxis and anaphylactoid reactions?
You can’t. They are clinically indistinguishable and equally life threatening
Risk factors associated with hypersensitivity to anesthetics
Female gender
Atopic history
Preexisting allergies
Previous anesthetic exposure
Treatment of anaphylactic and anaphylactoid reactions
-discontinue drug administration
-100% O2
-epi 0;01-0.5mg IV or IM
-consider intubation or trach
-IVF 1-2L LR
-Benadryl 50-75mg IV
-ranitidine 150mg IV
Hydrocortisone up to 200mg IV or methylprednisolone 1-2mg/kg
Anaphylactoid reaction
Resembles anaphylaxis but does not depend on IgE antibody interaction with antigen
This anesthetic drug is the most common cause of anaphylaxis during anesthesia
Muscle relaxants
Rocuronium, succinylcholine, atracurium
Account for 70% of reactions perioperativiely
Mechanism of anaphylactic reactions to muscle relaxants
IgE antibodies directed against tertiary or quarter army ion epitomes
How can a pt have an anaphylactic reaction to muscle relaxant during anesthesia if no previous exposure to muscle relaxants?
Bc OTC things (drugs, cosmetics, food products may contain some items) in muscle relaxants
Hypnotic agents that cause allergic reactions
Pentothal: 1 in 30.000
Propofol: 1 in 60,000
True allergies to etomidate, ketamine, and bentos extremely rare
Are allergic reactions to opioids common
Rare
Non-immune histamine release more common (morphine)
Reactions to local anesthetics
- rare allergic reactions
- vasovagal reactions
- toxic reactions
- side effects of epi
Reactions to Ester type local anesthetics
- IgE mediated reaction
- share common antigenicity with PABA
- cross reactivity should be expected
Allergic reactions to Amide local anesthetics
- true anaphylaxis extremely rare
- preservative paraben or methylparaben is causative
Is there cross sensitivity between Ester and Amide local anesthetics?
No
Allergic reactions to volatile inhalation agents?
No reports of anaphylaxis
Allergic reactions to antibiotics
*many true allergies are due to antibiotics
Running what antibiotic too fast can cause “red Man’s syndrome”?
Vancomycin
Name B-lactam antibiotics
PCN
Cephalosporin
This is the second most common cause of anaphylaxis during anesthesia
Latex
What type of sensitivity reaction is a latex allergy?.
Type IV sensitivity reaction to chemicals from manufacturing process
What foods can cross react with a latex allergy?
Mango Kiwi Chestnut Avocado Passion fruit Banana
What are some ways to avoid potential latex exposure during surgery?
- remove rubber stoppers from drug vials prior to use
- injections made through plastic stop cocks
- remove all latex from the room
- use latex free breathing bag
What pharmacologic prophylaxis can be used for latex allergy?
Pre-op administration of H1 and H2 histamine antagonists
Steroid coverage is controversial
This is a rare myopathy characterized by an acute hypermetobolic state in muscle tissue after induction of general anesthesia
Malignant hyperthermia
T/F: MH can occur without exposure to known triggers
True
Signs of MH
Hypermetabolism -increases CO2 -increased O2 consumption -metabolic acidosis -cyanosis -mottling Increased sympathetic activity -tachycardia -initial hypertension -arrhythmias Muscle damage -massester spasm -generalized rigidity -elevated serum creating kinase -hyperkalemia -hyperphophatemia -myoglobinemia -myoglobinuria Hyperthermia -fever -sweating
During MH, core temp care rise at as fast as what rate?
1 degree Celsius every 5 minutes
During MH, there is an uncontrolled increase of what in the intracellular skeletal muscle
Calcium
Dramatically enhanced and sustained _____ activity results in uncontrolled _______ in aerobic and anaerobic metabolism
ATP
Increase
During MH there is an efflux of what electrolyte?
Potassium
What receptor is abnormal in MH?
Abnormal Ryanodine Ryr1 receptors
- abnormal secondary messengers and modulators of calcium release
- abnormal sodium channel in skeletal muscle
Drugs known to trigger MH
- Halogenated general anesthetics
- non-depolarizing muscle relaxants (succinylcholine)
Treatment protocol of MH
- D/C anesthetic gas and succinylcholine
- call for help
- hyperventilate with 100% O2 at high flows
- give sodium bicarbonate 1-2mEq/Kg IV
- mix Dantrolene with sterile water and give 2.5mg/kn IV ASAP
- institute cooling measures
- give inotropes and antiarrhythmic agents PRN
- give additional doses of Dantrolene as needed up to 10mg/kg
- change anesthetic tubing and soda lime
- monitor urine output, labs, BP, ETCO2, and clotting studies
- treat severe hyperkalemia with dextrose, 25-50g IV and regular insulin 10-20u IV
- consider invasive monitoring (a-line, CVP)
- call hotline
How does Dantrolene work?
- hydantoin derivative
- directly interferes with muscle contraction by binding Ryr1 receptor, calcium channel and inhibiting calcium ion release from sarcoplasmic reticulum
- intracellular dissociation of excitation-contraction coupling
Dantrolene can also be used for treatment of what?
- Hyperthermia associated with thyroid storm
- neurolept malignant syndrome
- chronic spastic disorders
What is the greatest complication of acute administration of Dantrolene?
Muscle weakness, respiratory insufficient energy and risk of aspiration
How can you tell the difference between complete and partial laryngospasm?
Complete
-silent, paradoxical movement of the chest, tracheal tug, and not ventilation
Partial
-crowing noise, with mismatch between respiratory effort and ventilatory effectiveness
What is the most common way to break laryngospasm?
CPAP
What are some signs of bronchospasm?
Prolonged expiration
High inflation pressures
Expiratory wheezes
Decreased O2 saturation
This is caused by spasmodic constriction of bronchial smooth muscle creates narrowing of airway passages and increases airway resistance
Bronchospasm
What pts are at a higher risk of bronchospasm?
Asthmatics
What 3 things need to be present for a fire?
Ignition source
Oxidizing agent
Fuel source
What is the maximum acceptable trace concentration of anesthetic gases?
- N2O: <25ppm
- N2O and halogenated agent: < 25ppm adn 0.5 HA
- Halogenated agent only: 2ppm
How do you minimize radiation exposure in the OR?
- use proper barriers
- maximize distance from source
What is the maximum occupational whole body exposure annually for radiation?
5 rem/year
