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Anesthesiology - Monitoring 1

drraythe's version from 2016-04-15 10:26


Question Answer
Before you can know if there is a problem you need to know?What is normal
What are 6 things we can monitor during anesthesia?Anesthetic depth
Cardio fxn
Resp fxn
Renal monitoring
Temp monitoring
Laboratory monitoring (including blood gas analysis)
What are some physical signs you can use to monitor anesthetic depth?Palpebral reflex
Jaw tonicity
Heart rate
Resp rate
Hemodynamic/respiratory variations
2 electronic devices she mentions to monitor anesthetic depth?EEG (BIS).
EEG rxns to auditory stimulation (An electroencephalogram (EEG) is a test that detects electrical activity in your brain using small, flat metal discs (electrodes) attached to your scalp)
What are the 4 stages of general anesthesia?STAGE 1: Analgesia
STAGE 2: Excitement
STAGE 3: Surgical anesthesia
STAGE 4: Imminent death
Which stage of general anesthesia has voluntary movement?Stage 1 (Analgesia)
Stage 1 is called what? From when to when encompasses this stage?"Analgesia" stage. This is from beginning of induction to loss of consciousness
In which stage of anesthesia is there euphoria, ataxia, hallucinations & Hyperacusis?Stage 1 (analgesia) (Hyperacusis = Sensitivity to sound)
What is the stage of delirium/involuntary movement?Stage 2 (excitation)
Stage 2 is called what & from when to when encompasses this stage?EXCITATION stage. From loss of consciousness to onset of regular breathing
At what stage do you see salivation, vomiting, dilated pupils, tachycardia & hypertension?Stage 2 (excitement)
What should you avoid in stage 2 (excitation)?Avoid stimulation
Nystagmus is common in WHO, in what stage?Horses, stage 2 (excitement)
Laryngeal spasm is common in WHO, in what stage?Pigs & cats, stage 2 (excitement)
In what stage should you avoid stimulation?Stage 2 (excitement)
What is stage 3 called?Surgical ANx
Which stage is divided into planes/subcategories & what are these planes?Stage III (surgical anesthesia) can be divided into Plane 1, 2, 3 & 4 OR as light, medium & deep
During stage 3 there is progressive depression of....Reflexes
Plane 2 of Stage 3 is characterized by: ___ (level) of surgical anesthesia. The mm are doing what? How are the resp & pulse rate? How is the corneal reflex?MODERATE surgical anesthesia. There is adequate mm relaxation, stable resp & pulse rate & a strong corneal reflex
Which Phase of stage 3 is desired if mm relaxants are not used?Phase 3 of Stage 3 (3 is REALLY relaxed)
Phase 3 of Stage 3 has ___ (level) of surgical anesthesia. This Phase is desired when ___? What do the pupils look like?DEEP surgical anesthesia, desired Phase when mm relaxants not used. Pupil DILATION
What is stage 4 of anesthesia called?Asphyxia
How is stage 4 characterized? (What is CNS/resp/BP/pupils like? What should you know?)STAGE 4 = ASPHYXIA. CNS extremely depressed/pupils widely dilated. Resp ceases but terminal gasps are possible (hence asphyxia), BP is at shock level. KNOW THAT W/O INTERVENTION, DEATH CAN HAPPEN AT THIS LEVEL
Plane of surgical anesthesia is usually what?Stage 3, Plane 2
Who DOES have a palpebral reflex at a surgical plane of anesthesia? Who doesnt?DOES: HORSES, Maybe small rumis
DOESNT: Cats, Dogs, Cattle
Is there a corneal reflex at a surgical plane of anesthesia? (Stage 3, plane 2)YES, ALL SPECIES HAVE CORNEAL REFLEX AT THIS STAGE
Are there any species differences for blood pressure in the plane of surgical anesthesia?Everyone will have ↓ or same blood pressure, EXCEPT CATTLE! which will have ↑ BP (gotta keep that steak perfused)
How would you characterize respiration in the surgical plane of anesthesia? Is there any sp diffs?Regular, deep breathing (no sp diffs)
What is eyeball position/ocular signs like during the plane of surgical anesthesia for HORSES?Position is ventromedial. You will see a slow nystagmus & there will be lacrimation (my eyes would be bugging out & I would be crying too if I was nature's disaster being put under anesthesia)
What is eyeball position/ocular signs like during the plane of surgical anesthesia for DOGS/CATS?Position is ventromedial, but could become central
If a dog/cats eye position moves centrally during surgical plane of anesthesia, what does it mean?It could be getting lighter OR deeper...need to look at other factors to determine
What is eyeball position/ocular signs like during the plane of surgical anesthesia for CATTLE?Ventral (cows looking right down bc it was already expecting to be dead in the ground)
What is eyeball position/ocular signs like during the plane of surgical anesthesia for SMALL RUMIS?Slightly ventromedial (small is slight)
What should HR be like in surgical plan of anesthesia? Any sp diffs?Should be normal ("="), no sp diffs
What should CRT be like in surgical plan of anesthesia? Any sp diffs?<2 sec, no sp diffs
What should jaw tone be like in surgical plan of anesthesia? Any sp diffs?Should be NORMAL EXCEPT in DOGS/CATS where it is REDUCED.
In who can jaw tone be helpful to assess plane of anesthesia in & why?In CATS/DOGS, ESP CATS, there is a JAW TONE in the surgical plane of anesthesia
What are 6 things you should look at to monitor CV fxn during surgical anesthesia?CRT
Heart rhythm
7 different ways to monitor heart RATE?Auscultation
Heart palpation
Pulse palpation
Doppler ultrasound
Pulse oximeter
Blood pressure monitor
Electrocardiogram (ECG)
What does electrocardiography NOT tell you?NO info on the MECHANICAL fxn of the heart
NO indication of cardiac output
How will the ECG look w/ hypovolemia?NORMAL
How will ECG look w/ cardiopulmonary arrest? (Sudden stop in effective blood circulation due to the failure of the heart to contract effectively or at all)MAY appear normal (electromechanical disassociation) (bc not contracting but electrical signals might be going normally still)
Look at slide 36-28 for ideas of what ECG pathologies might look likeWhoopee
What DOES the ECG tell you?The electrical activity of the heart
What are 2 non-invasive (indirect) methods of measuring blood pressure?Oscillometric technique (BP cuff hooked to machine)
Doppler probe
What factors is cardiac output (CO) composed of?CO = HEART RATE (HR) x STROKE VOLUME (SV)
How is arterial blood pressure (ABP), cardiac output (CO) & systemic vascular resistance (SVR) related?ABP = CO x SVR (also remember that CO = HR x SV which is stroke volume)
Explain renal autoregulation of blood pressure & what happens if there is renal failure?Usually, as BP ↑, the kidney is able to maintain a stable blood pressure w/o increasing in the glom until a certain threshold. However, in renal failure, it is unable to regulate its own blood pressure & as BP ↑ there is a steady ↑ of the BP in the glom as well (kidney can regulate btwn 50-200mmhg...too low is too little perfusion & too high is going to damage the kidney)
What are the 3 basic machine/parts you need to measure an invasive blood pressure?A monitor, a transducer & a fluid-filled extension line (See pic on slide 34)
What is the gold standard for measuring BP?Invasive (direct) BP measurement
What are the 3 vessels which you can use in sm animals for a direct (invasive) BP measurement?Dorsal metatarsal ARTERY
Femoral ARTERY
What are the 3 vessels you can use in the horse for a direct (invasive) BP measurement?Facial artery
Transverse facial artery
Digital artery
What is the vessel you can use in a ruminant for a direct (invasive) BP measurement?Ear artery
The invasive blood pressure measurement measures what 2 things, which you calculate to determine what?Measures SAP (systolic arterial pressure) & DAP (diastolic arterial pressure) & from that you can calculate the MAP (mean arterial blood pressure)
(Not sure if ask, said in class but not in notes) how do you calculate the MAP (mean arterial blood pressure) from the information given to you w/ the direct blood pressure measurement?Direct gives you SAP & DAP, MAP = diastolic + 1/3(systolic-diastolic). (remember SAP is systolic arterial pressure & DAP is diastolic)
Look at pic on slide 37Explain oscillometric reading from machine or whatever
Explain how oscillometry (blood pressure cuff, indirect BP measurement) worksOcclusion of blood flow to extremity by the inflation of a cuff-detection of reappearance of blood flow during deflation
For oscillometry, the ideal cuff width is?40% of the circumference of the limb (so if you place the thin part of the cuff against the dogs arm it should be just slightly less than half the circumference of the dogs arm)
What will too wide of a cuff do to your BP reading?Underestimate (too loose= low reading)
What will too narrow of a cuff do to your BP reading?Overestimation
Where are some locations you can put the oscillator cuff?Base of tail
Back leg (above the point of the hock)
Arm below the elbow
Explain how the Doppler ultrasound worksA small probe is placed over the peripheral artery, which emits an ultrasound beam into the artery & creates swooshing sounds as blood pulses.
Explain how you take a blood pressure w/ a Doppler ultrasoundYou manually inflate the cuff to above systolic pressure, so you hear no noise. Then you slowly let pressure leak out of the cuff & at the pressure where you start to hear sound again, that's the SAP (systolic arterial pressure).
How accurate is the Doppler ultrasound compared to a direct ABP measurement? What are its limitations?Doppler has good agreement w/ the direct ABP measurements. The downsides are that you can't measure the DAP or MAP...estimation of the DAP by the disappearance of the signal is too subjective.
When is Doppler ultrasound especially useful?Very useful for small animals when the oscillometric method is often less reliable
Is there anything to note about species differences w/ the Doppler ultrasound?In CATS the Doppler is actually better at measuring the MAP than the SAP. This is bc the Doppler just measures kinda low in the cat. So altho what you read is considered the systolic & you should mark the paperwork as the systolic pressure, just be aware that it's actually closer to the MAP than the SAP. (In your head you can measure about 15mmhg to figure out what the SAP would be, but dont put that number on the record sheet)
Always consider the BP reading along w/ what 2 things?Color of MM & the CRT
What is the acceptable lower limit of blood pressure of the SAP? (sp diff?)90mmhg (no sp diff)
What is the acceptable lower limit of blood pressure of the MAP? (Sp diff?)60mmhg in small animals, but 70mmhg in horses
What is the acceptable lower limit of blood pressure of the DAP? (Sp diff?)40 mmhg (no sp diff)
What are some things you do to physically monitor the respiratory fxn?Look at chest excursions, re-breathing bag, rate, tidal volume, breathing pattern, mm color
What are the 4 big monitoring devices for monitoring resp. fxns?Pulse oximeter
Apnea monitor
Blood gas analyzer
Pulse oximetry combines what 2 things?Oximetry (O2 level in blood), w/ plethysmography (measuring changes in volume of blood)
What are the 2 components of the pulse oximeter?Light emitting diode, Photodiode detector
What is the lambert-beer law & what does it pertain to?It is the principal on which pulse oximetry (to monitor resp fxn) works. It states that oxygenated Hb absorbs more infrared light (940nm) & deoxygenated blood absorbs more red light (660nm)-allows you to compare the amt of oxygenated vs deoxygenated blood in an area (lambs love drinking red blood beer)
Explain how pulse oximetry measures the level of oxygenated bloodAll tissue is absorbing light - the difference is in the arterial blood, w/ the variable absorption due to pulsation of arterial blood (can also get a pulse from this)
What is SpO2?SpO2 stands for Peripheral capillary oxygen saturation. It is an estimation of the oxygen saturation level in the blood
What information does the pulse oximetry machine tell you?Info about cardiopulmonary fxn - O2 saturation of Hb w/ oxygen (SpO2) & pulse rate
What is the normal SpO2 range?96-100%
What info does the pulse oximeter NOT tell you?(Does tell you pulse rate & O2 saturation of Hb) Doesnt tell you about CO2 elimination & no info on hematocrit
Explain that there are different artifacts which can be picked up by a SpO2 machine. Name them (PICTURE ON SLIDE 51)Can be a motion artifact (suddenly jacks all around & drops to 0 for a sec)
there can be noise artifacts (follows basic curve but looks all fuzzy)
A poor perfusion artifact (where oximeter just start to press too much blood out of the peripheral tissue. line looks more flat)
SpO2 level doesnt tell you anything about...Anemia
Oxygen disassociation curve → what does this curve tell you?Graph which shows you the O2 saturation % against the oxygen partial pressure. It is determined by the "Hb affinity for oxygen". The equation is CaO2 (total arterial oxygen content) = (SaO2 x Hb x 1.34) +0.003(PaO2) (where the 1st parenthesis is the part bound to Hb & the 2nd parenthesis is what we have free in the blood not bound to Hb) (Kristen says: All u need to know is that @ 60 mmHg for the PaO2-saturation is 90% & below that the curve drops steeply-so hypoxemia will occur really fast after that point.)
What is the important part of the oxygen dissociation curve you should look out for?Once the oxygen saturation % starts to drop towards 90% & below, there is a STEEP ↓ in the oxygen partial pressure, which means there isn't enough push to get to the tissues/bind to Hb...So if it gets to near 90%, start to worry!