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Stage 1 of Anesthesia
1. From the beginning of induction to the loss of consciousness
2. Diminished sense of pain. Incision be feel like blunted object.
3. Amnesia
4. Responses to noises intensified
Stage 2 of Anesthesia
1. Variety of reactions innvolving muscular activity and delirium
2. Vitals show physiological stimulus
3. Possible violent behavior to minimal stimulation
4. Possible vomiting, laryngospasm, HTN, Tachy, uncontrolled movements.
5. Dilated pupils, nystagmus
6. Breath holding
Stage 3 of Anesthesia
1. Known as surgical or operative stage
2. Divided into 4 planes
3. NA responsible for determing plane for procedure
When is anesthesia appropriate for surgical procedure to begin?
Anesthesia is considered sufficient when painful stimuli does not elicit autonomic response or somatic reflexes.
Characteristics of Stage 3 Plane 1
Period of return of regular respirations to end of random eye movement
1. Eyeballs moist, show progressively decreasing activity.
2. Loss of lid (lash)reflex.
3. BP and Pulse normal
4. Loss of retching and vomiting reflexes.
Characteristics of Stage 3 Plane 2
End of random eye movement to the onset of relaxation of intercostals
1. Eyeballs fixed and slightly diverged
2. Corneal reflex lost
3. Laryngeal reflex lost (can insert ETT)
4. Resp. response to skin incision lost
5. BP and pulse near normal
6. Respirations begin to diminish r/t intercostal relaxation,
7. Abdominal relaxation


Characteristics of Stage 3 Plane 3
Onset to total relaxation of intercostals (apnea)
1. Respiratory Rate increased and tidal volume decreased
2. progressive pupillary dilation
3. Beginning of hypotension and tachy
Characteristics of Stage 3 Plane 4
Marked by Apnea (relaxation of diaphragm)
1. Marked pupillary dilation
2. Respirations jerky and shallow
3. BP falling with accelerated pulse
4. Complete muscle relaxation
Stage 4 of anesthesia
AKA-Medullary Paralysis. Period from cessation of resp to death
1.Fixed,Dilated, Unresponsive Pupils
2. Severe hypotension, then complete cardiac failure
3. All reflexes absent, flaccid paralysis
What is MAC?
1. The concentration of a particular inhalational anesthetic at one atmosphere pressure in which 50 percent of patients do not move in response to a skin incision

2. Typically dose should be a little higher
What organs are affected by inhalational anesthetics?
Primarilly the heart and lungs are impaired. However, every organ system is affected in one way or another.
What drugs are used for inducing anesthesia?
Thiopental, Etomidate, Propofol, Ketamine, Versed (rare)
Dosage/Onset for Thiopental Induction
Dose: 3-5mg/kg
Onset: 10-15 seconds
Dosage/Onset for Etomidate Induction
Dose: 0.2-0.4mg/kg
Onset: Less than 60 seconds
Dosage/Onset for Ketamine
Dose:1-2mg/kg
Onset: Within a few minutes
Dosage/Onset for Propofol
Dose:1.5-3mg/kg
Onset:30 seconds
Tissue Layers
Skin
Subcutaneous Fat
Supraspinous ligament
Interspinous Ligament
Ligamentum flavum
Epidural Space (fat, blood vessels, easy injection with no resistance)
Dura
Arachnoid
Subarachnoid Space (CSF is here)
Pia
Spinal Cord
Pia
Arachnoid Dura
Post. Ligament
Vertebral body
Anterior ligament
Major Vessels
What is the CSF volume?
25-35ml/hr secretion (total 150ish)

Replaced every 3 to 4 hours
What are the effects of a High Spinal?

1. Hypotension
a. slight decrease due to reduced SVR
b. severe reduction r/t decreased preload (venous pooling)

2. Arrhythmias
a. Brady most common r/t block of cardio-accelerator fibers (T1-T4)

3. Respiratory Depression
a. Intercostal nerve supply may be blocked, pt cannt feel themselves breathe. Normal voice=Normal ventilation

b. Diaphragmatic innervation       (C3,4,5)

c. Upper ext. sensory block r/t ascending level. Will complain of tingling or numb digits. Check grips for weakness. Brachial Plexus (C5,6,7,8,T1).

d. Hypoxia leading to restlessness, agitation. Whispering voice. INTUBATE


What is a Total Spinal?
Local anesthetic spreads high enough to block the entire spinal cord and may block the brain stem
What are complications associated with Total Spinal?
1. Complete block of sympathetic nervous system and severe arterial hypotension and bradycardia resulting in decrease CO.

2. Apnea, r/t respiratory muscle dysfunction or depression of the brain stem control centers
How do you treat a high spinal or total spinal?
DEGREE OF TREATMENT DEPENDS ON THE SEVERITY OF SYMPTOMS

1. 100% FiO2
a. place on circle system via mask to observe adequate Vt. Consider amnesia, sedation
b. Intubation/Ventilation if resp are depressed/absent or if CV system is unstable

2. Support BP
a. Fluid
b. Vasopressors

3. Treat Arrhythmias
a. Atropine-brady
b. Lidocaine-vent ectopy

4. Anticonvulsant
a. versed
b. pentothal if total SAB
What is the most important factor regarding dosage of drug for SAB?
Baricity in relation to patient position
What is baracity?
The specific gravity of the drug
What are the 3 classes of baricity?
1. Hyperbaric- more dense than CSF (falls)
a. typically locals mixed with 5-8% Dextrose
2. Isobaric- equal to CSF
3.Hypobaric- less dense than CSF (rises)
What are the complications of Regional Anesthesia?
1. Nausea and vomiting. Occurs with increased frequency with above T5.
2. Inadequate analgesia/anesthesia
3. Headache
4.Neurologic complications
a.Transient neurologic symptoms
b. Neurologic Injury (peripheral neuropathy)
c. Lidocaine Neurotoxocity
5. Urinary Retention
6. Cardiac Arrest during Spinal Anesthesia
7. Spinal or Epidural Hematoma
8. Infection:Meningitis, arachnoiditis, epidural abscess
9. IV infection, local toxicity
What is the cause of a Postdural Puncture Headache?
Dural puncture causes loss of CSF from the puncture site. Brain sags and causes tension.

Use of needles with large diameter. 25 or 27g are best to use.

Incidence decreases with age
Symptoms of a Postdural puncture headache?
frontal or occipital pain when sitting.
May have nausea, vomiting, and tinitus.
What is transient neurologic symptoms (TNS)
What are the symptoms?
1. Local toxicity at the nerve. Most often occurs with hyperbaric lidocaine

2. Sym: Back and leg pain, no motor involvement
What blocks usually cause urinary retention?
S2-4

Use of opiods in blocks increases risks among males
When do most spinal or epidural hematomas occur?
In the presence of coag or bleeding disorders.  Clot forms pressing on the spinal cord causing: sharp back and legg pain, progresses to numbness and motor weakness and/or sphincter dysfunction.

Must surgically decompress within 8-12 hours.
What are the Absolute Contraindications of a spinal anesthesia?
1. Coag/bleeding disorders
2. Increased ICP or intercerebral bleed
3. Spinal cord disease
4. Shock
5. Severe hypothermia
6. Infection at pain site
7. Pt refusal
8. Severe aortic or mitral stenosis
What are the relative contraindications to spinal anesthesia?
1. Sepsis
2. Uncooperative Pt
3. Preexisting neurologic deficits, demylinating lesions
4. Stenotic valvular heart disease
5. Severe spinal deformity
What are the 10 implications for management during spinal anesthesia?
1. Preload pt with fluid. 500-750ml. Caution in renal and CHF pts
2. Document pre-SAB vital signs
3. Give a little sedation before poke.
4. assist with positioning
5. Place in supine immediately post block
6.Check BP approx 1 min for 15-20min
7. MUST GIVE O2
8. Sedation PRN
9. Assess and document level of sensory block initially then at intervals
10. Document sensory block on PACU records
Order of block in spinal anesthesia
1. Autonomic Blockade
2. Sensory Blockade
3. Motor Blockade
4. Perioception Blockade

REMEMBER THAT THERE IS A 2 DERATOME SPREAD FOR EACH BLOCK
Why is it important to preload pt with fluids prior to administering a SAB?
WHen autonomic blockade is acheived there is a sympathetic loss causing loss of vasomotor tone.

Pt may become hypotensive and have devreased heart rate when block is at T1-4 causing block of the cardioaccelerator nerves.

Preload with 10-20ml/kg of fluids in the OR.
How much CSF lies in the lumbar area?
25-35ml
Describe a topical anesthetic
anesthetic is administered topically to desensitize a small area of the body for a very short period
Describe a local anesthetic technique
subq injection of a small area of the body with a local anesthetic. works longer than a topical
What is a nerve block
local anesthetic is injected into the nerve trunk or large nerve branch. the anesthetic drug creates numbness by blocking nerve impulses from being transmitted back to the brain
What is spinal anesthesia
injecting a local anesthetic into the subarachnoid space of the spinal canal

injected at L4-L5 space
what is epidural anesthesia
injecting the anesthetic into the epidural space of the spinal canal at any level of the spinal column

Used for continuous anesthesia for a prolonged period . a catheter is placed in the space
How many vertebrae are in the vertebral column? How many in each section?
33 vertebrae

7-cervical
12-thoracic
5-lumbar
5-fused sacral
5-fused coccygeal
What is a dermatome?
area of the skin supplied by a single, specific, spinal nerve root
Contraindications for LMA?
Hx of regurgitation and pulmonary aspiration, neck surgery
When to use a mask for oxygen delivery?
1. preoxygenation prior to intubation
2. short operative procedures
3. Initial airway control in resuscitation efforts
What are the indications for the use of an endotracheal tube?
1. airway patency if risk for aspiration
2. airway maintenance if masking is difficult
3. prolonged controlled ventilation
4. specific surgical procedures (ENT,crantiotomy)
What are the 3 common anticholinesterases used in anesthesia?
neostigmine, edrophonium, and pyridostigmine
What is the MOA, dose and duration of Succinylcholine?
MOA-attaches to endplate acetylcholine nictonic receptors and causes a continuous influx of Na ions into the muscle causing continuous depolarization. as long as the receptor is occupied the muscle is not able to repolarize

Dose: 1mg/kg IV
Duration: 5 min
How can fasiculations be prevented when using succinylcholine?
preadministration of a small dose of a nondepolarizing NMD
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