Emergence from Anesthesia Flashcards
How to assess the depth of NMB objectively?
Train of Four – Adductor Pollicis or Orbicularis Oculi
>90%- 0 twitches
90% – 1 twitch
80% - 2 twitches
75% - 3 twitches
<75% - 4 twitches (Will allow you to breathe with small tidal volume)
When is it okay to reverse with Neostigmine?
Objectively
Post-tetanic stimulation and return of 1 twitch = 10 mins
At least 1 twitch represents 90 % blockade and no free drug therefore, reliably reversible
Subjectively
Spontaneous respiratory effort
Less than 100% blockade, therefore, reliably reversible
Symptoms of cholinergic crisis?
Wet
Bronchospasm
Paralysis
Bradycardia
Symptoms of anti-cholinergic crisis?
Dry
Hyperthermia
Urinary Retention
Tachycardia
Delayed emergence
What is the minimum waiting time is necessary before administration of a steroidalneuromuscular blocking agent after administration of Sugammadex?
If rocuronium is reversed with Sugammadex, and rocuronium is readmistered within 30 minutes how long will the onset be delayed? How much shorter will the duration of action?
Onset delayed 4 minutes
Duration shortened 15 minutes
What is the recommended waiting time for patients with renal impairment that used rocuronium and reversed with 4mg/kg suggamadex? Or in healthy patients that were reversed with 16mg/kg suggamadex?
24 hours
What can you sometimes use to see if a patient is at baseline respiratory values?
Write respirometer
T or F. Spontaneous breathing with adequate TV is a reliable way to assess NMB reversal
Spontaneous breathing with adequate TV is still unreliable as diaphragm much more resistant to NMB than airway muscles (i.e. tongue)
False
Sustained tetanus 50-100Hz >5s without fade indicates only ____ blockade
50%
TOF, seeing 4 twitches are subjective and indicate only ___ blockade
75%
TOF ratio of _____is the gold standard and suitable for extubating*
>0.7-0.9
*Really not that reliable nor available
Okay to pull the tube? SpO2 > 93% on FiO2 < 0.5
Yes, as long as it is stong respirations and they are not hypertensive
Glabellar tap
Glabellar reflex (also known as the “glabellar tap sign”)
Primitive reflex
Elicited by repetitive tapping on the forehead
Patient blinks in response to the first several taps
Appropriate steps if surgeon needs a little more time
Propofol 20-50mg
Lidocaine 1-1.5mg/kg
ED95 of muscle relaxants is usually 1/3 intubating dose
Hyperventilate
Increase inhaled volatile concentration
N2O
Communicate with surgeon
Ruling out hypercarbia, hypoxia, hypotension - why would a patient wake up all crazy? What are appropriate treatments?
Emergence delerium
Treatment:
Don’t pull out ETT if haven’t already
Propofol
Fentanyl
Avoid verbal commands, and try not to use benzos
If you have to do a repeat does of succinylcholine, what should you be aware of?
Can cause bradycardia/arrest so give glycopyrrolate or atropine before redosing
What is the main mechanism behind a phase II block of succinylcholine?
This is due to increased activity of the sodium-potassium ATPase pump, which brings potassium into the cell in exchange for sodium. The receptor does not respond appropriately to acetylcholine, and neuromuscular blockade is prolonged.
Phase II has features of a non-depolarizing block on a nerve stimulator (fade)
How deeply paralyzed should a patient be for intraabdominal surgery?
In general, a 90% reduction of the twitch response or elimination of 2 or 3 in the TOF should suffice for intra-abdominal surgery
Name some negative effects of succinylcholine
asciculation’s hurt!!
Hyperkalemia
Cardiac arrest
Profound bradycardia (second dose) especially in kids
MH trigger
Pseuodocholinesterase deficiency
Should not be given 24 to 72 hours after burns, trauma, or denervation
Can cause arrest in kids (especially boys) with undiagnosed muscular dystrophy [Rosenberg Anesthesiology 77: 1054, 1992].
Threshold for TOF: need at least ___ to minimize riskof post operative complications
0.9
If the 4th twitch is 90% as strong as the first twitch then there is less than ___ blockade of receptors
70%
If the 4th twitch is less than 90% of the first twitch then there is greater than ____ blockade of receptors
70%
If quantitative TOF is not available, use tetanus- 5 seconds of ____. With a non-depolarizing NMBD, the response fades
50Hz
About how long does it take neostigmine to peak?
~10 min
If respiratory center is triggered, and patient is still at maintenance level of anesthesia:
If triggering CO2 <35, patient probably needs ________
If triggering CO2 > 50, patient probably does not need _________
If between 35-50, _____________________
If triggering CO2 <35, patient probably needs narcotics
If triggering CO2 > 50, patient probably does not need narcotics
If between 35-50, who knows (titrate to effect later)
Benefits of colloids
Contain large molecules that do not pass through semipermeable membranes
Remain in the vascular system to expand volume
Draws fluid from extravascular spaces by oncotic pressure
Work like hypertonic crystalloids but don’t require as much volume
Last longer than crystalloids
When would you use colloids?
Hyperproteinemia, malnourished pts who need plasma volume expansion but can’t tolerate the large infusions of crystalloids
Renal failure
Large trauma
Microsurgical
Expand intravascular volume by plugging leaking capillaries and increasing the colloid oncotic pressure
What is the natural colloid?
Human albumin solution
5% solution is iso-oncotic, leads to 80% initial volume expansion
25% solution is hyper-oncotic, leads to 200 - 400% increase in volume within 30 minutes. The effect persists for 16 - 24 h
What is a synthetic colloid?
Dextran
Highly branched polysaccharide molecules which are available for use as an artificial colloid
Used mainly to improve micro-circulatory flow in microsurgical re-implantations.
What colloid led to reduction in circulating factor VIII and von Willebrand factor levels, impairment of platelet function, prolongation of partial thromboplastin time and activated partial thromboplastin time, and increases bleeding complications?
Duration of volume expansion is 8-24hrs
Hetastarches, Hydroxyethyl starches (Hespan/ Hextend)- Synthetic
Third generation HES
6 % TETRASTARCH- VOLUVEN (waxy maize and potato)
Significantly less bleeding associated compared to second generations (15%), decrease in renal impairment, less accumulation in tissue
Among the safest and most cost efficient compared to Albumin
Dose-Up to 50 mL of Voluven® per kg of body weight per day (equivalent to 3 g hydroxyethyl starch and 7.7 mEq sodium per kg of body weight). This dose is equivalent to 3500 mL of Voluven® for a 70 kg patient..
When to use crystalloids?
Should be used in patients with dehydration, i.e., with loss of both interstitial and intravascular fluid
