TUTOR - EXAM 2

What values do we look at to see how well our patient is ventilating?

blood gases, ETCO2, SpO2

What are 3 causes of respiratory depression in our patient (think anesthetic drugs)?

opioids, alpha-2's, inhalant

What else can affect ventlation in out patients, besides anesthestic drugs?

-body positioning

-patient body condition

-V/Q mismatch (want to reduce where possible)

V/Q mismatch

-ventilation/perfusion mismatch

-Blood flow and air flow to lungs is required to carry oxygen to tissues and inhalant anesthetic to brain

What are the two options we have for ventilating for our patients?

-hand ventilation (us)

-ventilators

Whata are 3 tools we have to monitor our patients O2/ventilation?

-SpO2

-Capnography (ETCO2)

-blood gases

when bagging a patient, what do you want the pressure gauge to go up to (the max)

20 cm H20

How/why are the pulses affected by ventilation

causes a decrease in the typical negative pressure in the thoracic cavity, causing a decrease of blood flow to the heart (decrease CO)

- decreases BP (why we give fluids to fight against hypovolemia from the inhalant causing vasodilation)

what do you want the tidal volume of your patient to be in general

10-20 mL/kg

What is I:E ratio?

inspiratory: expiratory

for ventilators, what is the typical Inspiratory: expiratory ration to be

1:2

what is ETCO2 and what is the optimal range

end-tidal carbon dioxide- makes sure that carbon dioxide is carried through the blood, back to the lungs and exhaled

- 35-45 mmHg

what is capnometry

device that measures CO2 in expired air

Where do we get samples for blood gases from?

arterial lines/catheters

Which blood pressure gives the most accurate readings and instantaneous changes

Invasive BP

for invasive BPs, where should the transducer be?

at heart level, zero to atmosphere

When do we get blood gases on large animals?

routinely every 30-60 minutes

When do we get blood gases on small animals?

really only if you're worried about certain values

Normal pH range

7.35-7.45

what is paO2 measuring?

partial pressure of oxygen in artery

what is the paO2 normal range?

90-600 (300-400 is optimal)

What is paCO2 measuring?

partial pressure of carbon dioxide in arterial blood

What is the normal range for paCO2?

- SA: 35-45 mmHg

- LA: 45-55 mmHg

What is HCO3 measuring?

the amount of bicarbonate (form of carbon dioxide--brought to your lungs from blood

What is the normal range for HCO3?

- 18-26 mEq/L

What is TCO2 measuring ?

measuring TOTAL carbon dioxide

What is the normal range for TCO2?

-24-26 mEq/L

what is O2 sat measuring?

how much hemoglobin in your blood is carrying oxygen

What is the normal range for O2 sat?

>95%

What is base excess?

affects pH of blood

What is the normal range for base excess?

-5-5

term for the blood pH being too low

acidotic

term for the blood pH being too high

alkalotic

CO2 =

acid

What are 3 ways to measure ETCO2?

-side-stream sampler

-main stream sampler

-agent analyzer

What all can capnography do?

-measure respiratory ETCO2

-detects airway in difficulte intubations

-detects leaks

**does add 1-2 inches of dead space

Side stream sampler

will extract a small amount of system air to analyze

-must be connected to scavenge

Main stream sampler

obtains sample from direct souce

agent analyzer

this is helpful for knowing what is in the system

What does the pulse ox measure?

oxygen perfusion through tissues, also gives a pulse reading

What errors can occur with pulse ox

-dry tongue

- find non-pigmented tissue (pink such as tongue)

- outside lighting can confusing reading

- vasoconstriction

- severe amenia

why do we give fluids (3 reasons)

bp support, hydration, tissue perfusion

crystalloids- examples and duration

- plasmalyte, LRS, sodium chloride

-stays in vessel 30-45 minutes

colloids- what are they and examples

-larger molecular size, stays in the vessel longer

- synthetic (vetstarch)

- natural (blood, plasma)

What are 4 ways to deliver fludis to patients?

drip set, pressure bag, fluid pump, syringe pump

What is the maintenance fluid rate?

40-60 mLs/kg/day

What are the surgical/anesthetic fluid rates?

5-10 mLs/kg/hr

What are the shock/unstable patients fluid rates?

boluses

What are the 4 sources of anesthetic problems?

-human error

-equipment failure

-surgical complications

-adverse reactions to drugs

What are 4 sources of human error?

-inadequate history or physical examination

-anesthetist's lack of knowledge (ex. normals)

-incorrect drug administration/miscalculation

-inattentive anesthetist(lack of monitoring, fatigue)

What are some ways to prevent human error?

-ROUTINE

-know normals to differentiate between abnormal

-never be afraid to admit to a mistake

-always try to function at your best

What are some causes of equipment failure?

-equipment not serviced regularly

-Operator error

-Leak check failure

-Cost of equipment care

How can you as the anesthetist help control the equipment before it fails?

-try and identify the issue before calling service: this will be cheaper and you are able to start your procedures earlier w/o waiting for service to get there

What are 3 things that could happen in surgery to cause an "emergency"?

-Blood loss

-surgery involves respiratory or cardiac systems

-communication fallouts

As the anesthetist what should you be looking out for when there is blood loss?

-Recheck PCV/TP

-watch HR/BP (if significant amount HR will go up and BP will drop)

-always alert anesthesiologist

Blood volume is _______ of body weight

8%

How much of the 8% of blood volume are patients able to lose?

can lose up to 20% of the 8% of body weight

For a 20 kg dog, how much blood are they able to lose?

0.32 L

What is the maximum amount of blood loss that a patient can lose?

500 mL

How can location of the surgery impact the outcome of the surgery/likelihood of complications?

-If there is major vasculature nearby, they could hit something and cause significant blood loss

-If close to the lungs or hard, this could impact breathing/HR and eventually how your patient does under anesthesia

What are the 2 types of anesthetic emergencies ?

respiratory and cardiac

What drug would cause respiratory depression?

opioids cause hypoventilation

What are examples of ways an ET tube would be improperly placed?

-one lung intubation

-esophageal intubation

If your ET tube cuff is inflated too much, what could it cause?

-irritation/bruising

-trachea trauma (dyspnea)

What are examples of respiratory clinical complications?

-laryngospasms

-aspiration pneumonia

-tracheal tear

-apnea

-airway obstructions

-brachycephalics

-low inspired O2

How can you prevent trachea tear in your patients?

-ALWAYS disconnect a patient to move them

-never let metal stylets go past the end of the ET tube

What is an instantaneous snapshot of how your patient is doing respiratory and metabolically wise?

blood gases

What are some equipment errors that could cause respiratory complications?

-CO2 absorber exhausted

-No oxygen

-machine misassembled

-ET tube problems

-vaporizeer problems

-pop-off valve is closed

-mechanical ventilator misuse

What are some physiologic respiratory problems?

-pulmonary disease

-obese patients

-patient position

-hyper/hypoventilation

What are some examples of surgeries that could cause respiratory complications?

-laparoscopies

-thoroscopies

-species w/ large abdomens

Name all examples of cardiac emergencies?

-hypoxia

-acid-base imbalances

-electrolyte imbalances

-autonomic inbalances

-hypothermia

-air embolism

-toxicity

-inappropriate drug adminstration

-shock, anemia

-cardiac disease

What will you see on the monitor if your patient is starting to have cardiac problems?

-changes in HR or rhythm

-abnormal respiration

-abnormal ECG arrhythmias

-changes in BP

What will you physically see on your patient if they are starting to have cardiac problems?

-changes in pulse quality

-prolonged CRT

-cyanosis

-abnormal respiration

What is the anesthetist role in cardiac emergencies?

-communicate w/ doctor

-support patient if clinical (reduce inhalant, breathe for patient more, ask doctor if you are able to give meds)

-be ready to provide treatment if the doctor gives you the order (calculate emergency drugs)

What is lactate?

build up of lactic acid that is most commonly caused by inadequate amounts of oxygen in cells and tissues

What are causes of respiratory failure?

-hypoventilation or hypercarbia

-low inspired oxygen

-PDA shunt

Why could a shunt (PDA) cause respiratory failure?

with a shunt, blood flows from left to right (which is the opposite of normal blood flow), due to this there is reduced oxygenation to body and heart muscles.

What can a decreased temperature lead to?

bradycardia

What are other things that can happen when your patient is hypothermic?

-hypotension

-deeper plane of anesthetic

-reduced response to anticholinergics

What is the acid -base imbalance mean?

Respiratory or metabolic dysfunction causes can change pH

What can electrolyte imbalance mean for your patient?

Electrolytes are critical for nerve, muscle and heart function, if they are decreased/increased this can cause heart issues (think back to physio: sodium and potassium pumps)

What can you do to resolve electrolyte imbalances?

usually fluids help, can also supplement with the electrolyte that is needed if fluids aren't working

What is autonomic imbalance usually caused by?

surgical stimuation(vage response)

what can autonomic imbalances cause?

sudden bradycardia

What can cause cardiac toxicities?

-improper adminstration of drugs (route, time, amount of drug)

-miscalculated doses of local analgesics (ONLY lidocaine can go IV)

What should you always do to your patient to catch cardiac disease?

auscultate

With shock and anemia, what can you do prior to anesthesia?

-attempt to resolve them, such as given blood transfusion, or fluid bolus to correct shock or dehydration

What age of veterinary patients are considered neonates?

less than 3 months of age

How is anesthesia for neonates different than adults

neonates are higher risk and require special attention for their needs

Name all major organ systems that are underdeveloped in the neonate

-cardiovascular

-pulmonary

-thermoregulatory

-renal

-hepatic

by what age are these organ system usually developed?

12 weeks

What is dependent for cardiac output in neonates?

Heart rate

True or False: neonates have more cardiac reserve

False

What do you need to be careful with for neonates relating to their cardiac reserve?

The have little cardiac reserve so you need to be careful about administering IV fluids

What is the key to anesthetizing the neonatal patient?

maintaining heart rate

Do neonates have a higher or lower resting respiratory rate?

higher

What are some complications with neonates associated with the respiratory system?

small airways, pliable ribcages, higher resting RR

Why do we need to be concerned about neonates having a pliable rib cage?

they will have to work harder to breathe and potentially get respiratory fatigue

True or false: neonates have an immature sympathetic nervous system

true

Do neonates have an increased or decreased response to the stress of anesthesia?

decreased