OR Concepts Flashcards by Alex Sextro

baroreceptors

pressure receptors in aortic arch and carotid sinuses

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baroreceptor reflex

if it senses low BP then increases cardiac output (and opposite)

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reflex bradycardia

when vasoconstriction causes the heart rate to decrease (phenylephrine)

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relex tachycardia

vasodilation causes heart rate to increase (propofol)

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carotid sinus

contains baroreceptors

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carotid body

primarily sense hypoxia

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Cerebral vascular accident

stroke

brain cell death due to loss of blood flow

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What are the possible causes of stroke?

1- blood clot
2- intracranial hemorrhage
3- prolonged hypotension
4- hypertension

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Deep venous thrombosis (DVT)

blood clot in a vein

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What patients are at risk for developing DVT?

bedridden patients

heart arrhythmias that decrease blood flow through the heart

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pulmonary embolism

DVT moves into the lungs

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How do you decrease the risk of developing a DVT during surgery?

compression stockings

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edema

excess fluid in the interstitial space

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pulmonary edema

excess fluid in the alveolar spaces (usually caused by heart failure)

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preload

volume that is returned to the right ventricle

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afterload

resistance the left ventricle has to pump against

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Will a patient with hypovolemia have a high or low preload?

low

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will a patient in REVERSE trendeleburg have a high or low preload?

low

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How do you monitor preload?

central venous pressure

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what is the blood pressure in the superior vena cava normally?

5-12mmHg

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If a patient is hypertensive then will the afterload be high or low?

high

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If someone was bleeding to death and had low blood pressure would the afterload be high or low?

high

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transmural pressure

the difference in pressure between two sides of a wall or equivalent separator

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negative pressure pulmonary edema

trying to inhale while airway is obstructed

bite on ETT
laryngospasm

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systemic vascular resistance (SVR)

resistance that the left ventricle must pump against

pulmonary vascular resistance (PVR)

resistance that the right ventricle must pump against

Is SVR or PVR normally lower?

PVR

cautery/bovie

cut and burn at the same time

grounding pad

used in cautery in order to make a full circuit

list the electrical loop for cautery

``` machine bovie patient grounding pad machine ```

should the grounding pad be placed on muscular or non muscular area?

muscular area so that it is well perfused to dissipate heat

difference between unipolar cautery and bipolar cautery

unipolar must have a grounding pad and more current flows through the body

advantages of bipolar cautery

less current flow through body | control cautery in delicate areas

disadvantage of bipolar cautery

cauterizes small areas not good for controlling large amounts of bleeding

why is it not likely to be electrocuted by cautery?

ultra high current frequencies (>200,000 Hz)

Can a patient get burned if they have a piercing?

yes the current could pass through metal and cause burn

what could you do if the patient could not take the piercing out?

place the grounding pad away from the metal

pneumoperitoneum

abnormal presence of air or other gas in the peritoneal cavity

implications of laparoscopic surgery (8 things)

``` 1-intubation required 2- atelectasis more likely 3- hypercarbia 4-vagal response common 5- decrease CO 6- BP up or down 7-pain in the shoulder (phrenic nerve) 8- possible pneumothorax ```

When to use a 8.0 ETT?

laparoscopic surgery in the Trendelenburg position | it decreases the resistance of ventilation, lowers PIP

CO2 gas embolism

infusion of CO2 into a vein or artery and results in blockage

what is CO2 injected into the abdominal cavity with?

veres needle

what causes a CO2 gas embolism?

misplacement of veres needle

subcutaneous emphysema (SubQ)

trapped air under the skin | occurs as CO2 diffuses into the subQ space

What would happen if you increase the pressure in the abdomen with CO2 above 20mmHg?

too high and increase the likelihood of tissue dissection and subQ

What is the safe range of pneumoperitoneum pressure?

0-20 | 12-14 recommended

What is the clinical significance of subQ?

hypercarbia | acidosis

Would you extubate a patient that had SubQ?

What are the four purposes of an OG/NG tube

1- decompress stomach 2-can vent gases (bowel obstruction) 3- tube feedings 4-empty stomach of poison or drug OD

should you use a OG tube during laparoscopic surgeries? Why or why not?

yes, decreases the chance of injury upon trocar insertion and improves surgical view

ileus

gastroparesis as a side effect of surgery

T/F NG tubes are indicated for most open abdominal surgeries

true, patient is at risk of post op ileus

Do OG tubes usually stay in post op? What about NG tubes?

OG tubes are temporary and usually come out | NG tubes usually stay in post op

What is a contraindication for NG tube?

blood thinners | facial fracture

What is a dangerous thing that can happen from incorrect placement of an NG tube

NG tube in brain if you don't angle it correctly

Do you place OG/NG tubes in patients with prior gastric surgery?

no | if you must radiology must aid

T/F OG/NG tubes are safe to place in patients with liver failure.

false, they could have esophageal varices and could rupture

cirrhosis

liver failure

anaphylaxis

excess histamine release

what are the two main problems with anaphylaxis?

1- vasodilation (leak into interstitial space and cause localized edema (hives)) 2-bronchoconstriction

anaphylaxis treatments

1- subcutaneous epinephrine 2-bronchodilator 3-histamine blocker 4- steroid

what is the epi dose for adults and peds for anaphylaxis?

adult 100-500mcg | peds 10mcg/kg

benadryl

histamine blocker | 25-50mg

compartment syndrome

decrease in the blood flow to a body compartment due to increased pressure inside the compartment

what is the treatment for compartment syndrome?

surgical fasciotomy

what are possible causes of compartment syndrome?

fracture infiltrated iv tight cast

vagal response

bradycardia | hypotension

when can you commonly see the vagal response?

laparoscopic surgery eye surgery abdominal/uterine surgery

stress dose of steroids

steroids "enhance" the effectiveness of catecholamines

catecholamines

hormones released by adrenal glands | -dopamine, NE and Epi

what does chronic steroid use do to the catecholamines?

decreases their effectiveness if steroids are not taken that day, may decrease the effectiveness of vasopressors

What steroids are in our pyxis that can be used for a stress dose?

solu-medrol (most common) | solu-cortef

abdominal splinting

hypoventilation cause from the pain of breathing

how do you counteract abdominal splinting?

narcotic nerve blocks local anesthetic