Anesthesiology Flashcards
This is the process of blocking the perception of pain and other sensations. This allows patients to undergo surgery and other procedures without the distress and pain they would otherwise experience.
Anesthesia
This is the term for a reversible loss of consciousness.
Genera Anesthesia
This is the reversible loss of sensation in a (small) pat of the body by localized administration of anesthetic drugs at the affected site.
Local Anesthesia
This is the reversible loss of sensation and possible movement in a region of the body by selective blockade of section of the spinal cord or nerves supplying the region.
Regional Anesthesia
What are the goals of anesthesiology?
- Analgesia
- Sedation
- Reversible loss of consciousness
- Amnesia
- Muscle Relaxation
- Hemodynamic Stability
- Fast Recovery
Types of Anesthesia
- Inhaled Anesthesia (NO, Sevofurane/Isofurane)
- Sedative/Hypnotic
- Opioids
- Neuromuscular Blocking Agents
Is a patient is under minimal sedation (anxiolysis), how would you expect the person/body to respond?
- Normal response to verbal commands
2. Normal CV and Respiratory Status
Is a patient is under deep sedation, how would you expect the person/body to respond?
- Patient cannot be easily aroused
- Purposeful response to repeat or painful stimulation
- Airway and ventilation may be impaired
- CV-status maintained
Is a patient is under general anesthesia, how would you expect the person/body to respond?
- Loss of conciousness
- Airway and ventilation may need to be secured and maintained.
- CV-status may be impaired
Is a patient is under moderate sedation (conscious sedation), how would you expect the person/body to respond?
- Purposeful response to verbal commands
2. Maintained airway, ventilation, CV-status.
What are the common sedatives?
- Benzodiazepines (midazolam/diazepam)
- Barbituates (thiopenthal/methohexital)
- Ketamine (Dissociative anesthesia, cataleptic state, raises ICP)
- Etomidate (Common agent used in RSI, causes adrenal suppression)
- Propofol (Common induction agent, GABA)
What are the common general anesthetics?
- Gases
2. Sedative (Opiates)
A measurable effect of anesthetic gases is the production of immobility and amnestic effects as defined by the ___________ of anesthetic required to suppress movement to a surgical incision in 50% of patients .
MAC (Minimal Alveolar Concentration)
How do gases make their immobility effects? How do we know the measure?
Action on the spinal cord. MAX determined by decerebrate animals.
What are the targets of the amnesic effects of gases?
- Amygdala
- Hippocampus
- Cortex
Common gases used as anesthetics
- NO
- Diethyl Ether
- Chloroform
- Halothane
- Methoxyflurane
- Enfurance
- Isofurane
- Sevofurane and Desfurane
How can we relax the muscle at the Neuromuscular Endplate?
- Non-depolarizing Neuromuscular Blocking Agent
- Long = Pancuronium
- Medium = Vecuronium/Rocuronium/Atracurium/Cisatracurium
- Short = Mivacurium - Depolarizing Neuromuscular Blocking Agent
- Succinyl Choline 30-60 sec onset effect lasting 5-10 minutes
How can we relax the muscle at the Nerve Conduction?
- Peripheral Nerve Blocks
- Epidural Anesthesia
How can we relax the muscle at the Nerve Conduction?
Spinal Anesthesia
When putting a patient under anesthesia, what is important to do?
Hemodynamic Stability!!
- Pt requirements
- Coronary Perfusion
- Heart Rate/Rhythm
- Cerebral Perfusion
- Intentional Hypo/Hypertension
When would you want intentional hypotension? Hypertension?
Hypo - in cases of bleeding
Hyper - cases of low perfusion, concern of cerebral ischemia
Types of Regional Anesthesia
- Epidural Anesthesia
- Spinal Anesthesia
- Regional Block
- Bier Block
Effects of Epidural Anesthesia
- Block of sensation of affected dermatomes
- Motor block of affected dermatomes
- Block of pain
- Block of sympathetic response
- Block of vagal response
Contraindications of Epidural Anesthia
Regional
- Pt unable to comprehend procedure
- Prior back surgery or back pain
- Fixed cardiac output states (AS)
Absolute
- Patient refusal
- Infection of skin
- Sepsis
- Patient anticoagulated
- Increased intracranial pressure
Positives of Epidural Anesthesia
- Patient Awake
- No depression of the baby
- Postop analgesia
- Postop breathing
- Less risk of thrombosis
- Earlier intestinal motility
- No intubation
Negatives of Epidural Anesthesia
- Failure of block
- Bleeding
- Infection
- Wet tap
- Bradycardia
- Hypotension
- Breathing difficulty
Effects of Spinal Anesthesia
- One Shot
- Continuous Spinal Anesthesia
- Bilateral Block
- Unilateral block
- Speed of onset
- Possibility of high spinal
Contraindications of Spinal Anesthesia
Regional
- Pt unable to comprehend procedure
- Prior back surgery or back pain
- Fixed cardiac output states (AS)
Absolute
- Patient refusal
- Infection of skin
- Sepsis
- Patient anticoagulated
- Increased intracranial pressure
- Additional risk of heart failure due to increase in preload
- Additional risk of sympathetic activation
- Risk is muscle relaxation is needed
Examples of Regional Block
- Peripheral Nerve Blocks
- Brachial Plexus Block (interscalene/infraclavicular)
- Lumbar Plexus block
- Continuous Nerve Sheath
Choice of General Anesthesia
- Total IV anesthesia
2. Balanced anesthetic
Methods of General Anesthetic Control
- Oral and nasal airways
- Mask anesthesia
- LMA
- Endotracheal intubation
Complications that can cause airway issues.
- Difficult Airway (See next card)
- GERD
- Full Stomach
- Unstable Neck
What can cause a “difficult” airway?
- Mallampati Classification
- Mentomhyoid Distance
- Mouth Opening
- Neck Mobility
- Buck Teeth
- Big Tongue
GERD and Full stomach are complications to think about in patients with:
- Hx of GERD
- Hx of ESLD and Ascites
- Any Trauma
- Preggo
- DM of long duration with supposed gastroparesis
What general anesthesia can we use for patients with GERD/Full Stomach?
- Rapid Sequence Induction
- Cricoid Pressure
- Awake Fiber Optic Intubation
What can cause an “unstable neck?”
- Trauma
- Cervical Spine Fracture
- Atlanto-Occipital Instability
- Spinal Cord Stenosis
What general anesthesia can we use for patients with an unstable neck?
- Awake Fiberoptic Intubation
- Awake Positioning
- In-line Stabilization
What are ways to secure the Airway?
- Mask Ventilation
- Direct Laryngoscopy
- LMA/Intubating LMA/Combitube
- Fiberoptic Methods (Bronchoscope flexible, Bronchoscope rigid, Bullard)
- Transtracheal Jet Ventilation
- Tracheotomy
Pre-Op Assessment for COPD Lung Cancer and Lung Resection
- PreOp Spirometry
- >1.5 Lobectomy
- >2 Pneumonectomy
- >80% predicted - Review Imaging
- If no unexplained parenchymal dz then average risk
- If unexplained diffuse parenchymal dz on CXR/CT then measure DLCO
- If DLCO 40% then average risk
- If FEV1 or DLCO < 40 CPET if VO2 Max < 15 then high risk
Pre-Op Assessment for Cardiac Issues
- Unstable Coronary Symptoms (Recent MI and risk of ischemia by clinical symptoms or noninvasive testing; Unstable Angina)
- Severe Valvular Dz
- Decompensated Heart Failure
- Significant Arrhyhtmias (High degree AV Block; Supraventricular Arrhythmia with uncontrolled HR; Symptomatic Ventricular Arrhythmia with underlying heart dz)
What would constitute as an intermediate predictor?
- Mild Angina Pectoris
- Previous MI by hx or pathological Q waves
- Compensated or prior heart failure
- DM
- Renal Insufficiency
What would constitute as a minor predictor?
- Advanced Age
- Abnormal EKG (left ventricular hypertrophy, LBBB, ST-T abnormality)
- Rhythm other than sinus
- Low functional capacity
- Hx of Stroke
- Uncontrolled Systemic HTN
What would require further pre-op testing?
2 out of 3 as a positive of the following:
- Intermediate Clinical Predictors
- Low Functional Capacity
- High Surgical Risk (Aortic Sx, Peripheral Vascular Procedures, Long procedures with fluid shifts and blood loss
What are non-invasive tests? (Idk what this has to do with sx or anesthesia?)
- Stress Test
- Thallium Test
- Dobutamine Stress Echocardiography
- Dipyridamole or Adenosine Perfusion
- Holter Recording
**If any of these are positive proceed to Coronary Angiography
Sometimes patients can be aware without changes in HR or BP, why is this possible?
- No universal anesthetic method
- Anesthesia occurs along a continuum (interpatient pharmacokinetic variability)
- Any cortical activity may be able to reach the hippocampus for the formation of a memory
