Anesthesia Curriculum Flashcards
Normal lung volumes (TLC, TV, VC, FRC)
Normal lung volumes (RV, ERV, IRV, FVC)
Effects of general anesthesia on the FRC
Hgb dissociation curve
Five etiologies of hypoxemia
Mallampati
Hyomental distance
- >3 cm is favorable for intubation
Thyromental distance
- > 6cm is favorable for intubation
Normal head extension
At least 35 degrees
Basics of the airway exam: The four M’s
- Mallampati
- Measurements (Hyomental, thyromental)
- Movement (Head extension)
- Malformation (anything obstructive or loose, BMI)
Airway emergency
Cannot intubate AND cannot ventilate
In other words, if you cannot intubate but you can bag and mask ventilate, it’s not an airway emergency.
Rapid sequence intubation
Induce the patient with an anesthetic and give a muscle relaxant (usually Succinylcholine or Rocuronium) that works fast in order to intubate the patient as soon as possible without mask ventilation
A rapid sequence induction is a good choice for patients that are at increased risk for aspiration (trauma, GERD, pregnant, diabetic gastroparesis, full stomach)
When a patient with 100% O2 sat is cyanotic, you always need to consider two things
- Carbon monoxide
- Methemoglobinemia
Cormack and Lehane classification
- Grade 1 view: all of vocal cords/laryngeal aperature
- Grade II view: arytenoids only
- Grade III view: epiglottis only
- Grade IV view: palate only
Levels of anesthesia
Minimal Sedation (Anxiolysis)
a drug-induced state during which patients respond normally to verbal commands.
Although cognitive function and physical coordination may be impaired,
airway reflexes, and ventilatory and cardiovascular functions are unaffected.
Monitored Anesthesia Care (“MAC”)
- Does not describe the continuum of depth of sedation
- Rather it describes “a specific anesthesia service performed by a qualified anesthesia provider, for a diagnostic or therapeutic procedure.”
- Indication: “the need for deeper levels of analgesia and sedation than can be provided by moderate sedation (including potential conversion to a general or regional anesthetic.”
Moderate Sedation/Analgesia (“Conscious Sedation”)
drug-induced depression of consciousness during which patients respond purposefully to verbal commands, either alone or accompanied by light tactile stimulation.
No interventions are required to maintain a patent airway, and spontaneous ventilation is adequate. Cardiovascular function is usually maintained.
Deep Sedation/Analgesia
a drug-induced depression of consciousness during which patients cannot be easily aroused but respond purposefully following repeated or painful stimulation.
The ability to independently maintain ventilatory function may be impaired. Patients may require assistance in maintaining a patent airway, and spontaneous ventilation may be inadequate. Cardiovascular function is usually maintained.
General Anesthesia
a drug-induced loss of consciousness during which patients are not arousable, even by painful stimulation.
The ability to independently maintain ventilatory function is often impaired. Patients often require assistance in maintaining a patent airway, and positive pressure ventilation may be required because of depressed spontaneous ventilation or drug-induced depression of neuromuscular function. Cardiovascular function may be impaired.
The laryngeal mask airway partially protects the larynx from ___, but not ___.
The laryngeal mask airway partially protects the larynx from pharyngeal secretions, but not gastric regurgitation.
The earliest evidence of bronchial intubation often is an increase in ___.
The earliest evidence of bronchial intubation often is an increase in peak inspiratory pressure.
Ensuring that when you intubate someone you haven’t gone into the esophagus
- direct visualization during intubation
- presence of bilateral breath sounds
- absence of gastric gurgling while ventilating
- analysis of exhaled gas for the presence of CO2
- chest radiography, airway ultrasonography, or use of fiberoptic bronchoscopy
Closing capacity
- The maximal lung volume at which airway closure can be detected in the dependent parts of the lungs
- Closing capacity is normally well below FRC, but it rises steadily with age. This increase is probably responsible for the normal age-related decline in arterial O2 tension.
FEF25-75 utility in obstruction
Whereas both forced expiratory volume in the first second of exhalation (FEV1) and forced vital capacity (FVC) are effort dependent,
forced midexpiratory flow (FEF25–75%) is more effort independent and may be a more reliable measure of obstruction.
Effects of the mechanics of anesthesia on the FRC
- Changes in lung mechanics due to general anesthesia occur shortly after induction.
- The supine position reduces the FRC by 0.8 to 1.0 L,
- and induction of general anesthesia further reduces the FRC by 0.4 to 0.5 L.
- Net: reduction by 1.2 to 1.5 L
- FRC reduction is a consequence of alveolar collapse and compression atelectasis due to loss of inspiratory muscle tone, change in chest wall rigidity, and upward shift of the diaphragm.
Anesthesia and shunt
General anesthesia commonly increases venous admixture to 5% to 10%, probably as a result of atelectasis and airway collapse in dependent areas of the lung.
Direct effects of alveolar CO2 on O2
Large increases in PaCO2 (>75 mm Hg) readily produce hypoxia (PaO2 <60 mm Hg) at room air,
but, not at high FiO2.