OR Concepts Flashcards by Shalini Raghuraman

pressure receptors that detect pressure of blood flowing through the arteries

baroreceptors

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where are baroreceptors located?

) carotid sinuses

2. ) aortic arch

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how does the brain try to correct for a low blood pressure?

the brain stimulated the ANS to increase the heart rate (increases cardiac output)

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vasoconstriction causes the heart rate to decrease

reflex bradycardia

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vasodilation causes the heart rate to increase

reflex tachycardia

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contains baroreceptors that adjust heart rate to maintain normal cardiac output/blood pressure?

carotid sinus

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cluster of cells that primarily sense hypoxia and stimulate faster respirations

carotid body

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refers to sudden brain cell death caused by inadequate blood flow

cerebral vascular accident; stroke

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possible causes of stroke (4)

) blood clot
) intracranial hemorrhage
) prolonged hypotension
) hypertension

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refers to blood clot in a vein (usually in the legs)

deep vein thrombosis

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Examples of pts at risk for developing blood clots:

) bedridden pts that cant ambulate

2. ) heart arrhythmias that decrease the blood flow through heart

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when a DVT becomes dislodged from the legs it can move to the heart and lungs causing ____.

pulmonary embolism

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How to prevent DVT? (3)

walking/movement/ ambulation
blood thinners ( medication)
sequential compression stockings during surgery (squeeze the legs and promote blood flow)

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excess fluid in the interstitial space

edema (“swelling”

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excess fluid in the alveoli; caused by some degree of heart failure ( which causes some blood to back up into the lungs)

pulmonary edema

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refers to “venous return” or VOLUME of blood that is returning to the right ventricle and available for the heart to pump on the next contraction

preload

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refers to the RESISTANCE the left ventricle has to pump against

afterload

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True/False: pt with a low blood volume (bleeding pt) will have a decreased venous return or low preload

true

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how does a pt’s position in Trendelenburg affect preload?

it will INCREASE preload

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how can you measure preload?

central venous pressure (CVP)

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what is central venous pressure?

blood pressure within the superior vena cava (5-12 mm Hg)

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If pt is supine…a low CVP indicates ___ ____

low preload

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if pt is supine a high CVP indicates ____ ____

fluid overload (usually in heart failure and renal failure pts)

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vasoconstriction = ___ afterload

high afterload

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vasodilation = ___ afterload

low afterload

example of patient with high afterload yet low blood pressure

exsanguinating patients (bleeding to death)

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

transmural pressure

clinical example of transmural pressure is ___ ___

pulmonary edema

explain how pulmonary edema affects transmural pressure

pressure in the lungs on one side of the membrane becomes drastically reduced; means pressure on the other side of the membrane is relatively much higher which can lead to blood entering the lungs from the pulmonary capillaries

occurs when a patient tries to breathe while their airway is obstructed

negative pressure pulmonary edema

2 examples of negative pressure pulmonary edema

1. the pt bites down on their ETT tube during emergence | 2. the patient experiences a laryngospasm

Explain what happens when pts bite down on their ETT tube and experience larygospasm and how that contributes to pulmonary edema

intrathoracic pressure becomes more and more negative as the patient breathes (b/c air from the atmospher cannot enter the lungs); the negative pressure inside the lungs will "suck" blood into the alveoli from the pulmonary capillaries causing pulmonary edema

refers to resistance that the left ventricle must pump against and it is affected by peripheral arterial vascular tone

systemic vascular resistance

arterial vasoconstriction= ____ SVR

high SVR

arterial vasodilation = ___ SVR

low SVR

refers to the resistance that the right ventricle must pump against, and is affected by the vascular tone in the pulmonary arteries

peripheral vascular resistance (PVR)

pulmonary artery vasoconstriction = ___ PVR ; while pulmonary artery vasodilation= ___ PVR

high PVR; low PVR

True/False: PVR is usually much higher than SVR.

FALSE; lower than SVR

what must be placed in order for a bovie to work?

grounding pad

where is ground pad usually placed to dissipate heat?

thigh

advantages of bipolar cautery (2)

1. less current flow through the body | 2. the surgeon can control cautery in delicate areas

Why doesnt a patient get electrocute with a cautery?

because the cautery is set on a ultra high current frequency (> 200,000 Hz) which allows the current to pass through the body w/o electrocution

8 implications of pneumoperitoneum (CO2 insufflation)

1. ) intubation is required 2. ) atelectasis is more likely 3. ) hypercarbia is more likely 4. ) a vagal response is somewhat common 5. ) cardiac output decreases 6. ) blood pressure can go up or down 7. ) pts can get referred pain in the shoulder 8. ) partial pneumothorax (collapsed lung)

When would you use a larger diameter ETT tube?

obese pt in trendelenburg with abdomen insufflated with CO2

how does a larger diameter ETT help with an obese pt in trendelenburg with/ abdomen insufflated with CO2?

decreases the resistance of ventilation and lower the peak inspiratory pressure required to effectively move the patient's diaphragm

can occur with accidental infusion of CO2 into an injured vein or artery and results in blockage of the right ventricle

CO2 gas embolism

refers to trapped air underneath the skin and can occur during laparoscopic sx as CO2 diffuses into the subcutaneous space

subcutaneous emphysema

factors that can cause subQ emphysema (6)

1. multiple attempts of abdominal entry 2. improper cannula placement 3. increased intra-abdominal pressure 4. procedures lasting >3.5 hours 5. gas flow rate 6. high total gas volume

"safe" range for pneumoperitoneum

0-20 mmHg; RECOMMENDED: 12-14 mm HG

When is extubation contraindicated during subQ emphysema? (3)

1. ETCO2 is elevated 2. airway swelling 3. crepitus (crackling, crinkly, or grating feeling or sound under the skin)

purpose of OG/NG tubes (4)

1. can decompress the stomach 2. can vent gases if pt has a bowel obstruction 3. can deliver tube feedings directly to the stomach 4. can empty the stomach of poison or drug overdose

indications using a OG tube

intubated pts w/ full stomach or undergoing laparoscopic surgery

indications for NG tube

most open abdominal procedures, b/c abdominal sx increases the risk of a pt developing postoperative ileus

defined as gastroparesis and can lead to abdominal distention

ileus

When do NG usually stay in ?

postoperatively

when should you avoid using an OG/NG tube? (2)

1. ) for pts who have had prior gastric surgery; if it needs to be done need to use radiology 2. ) pts with liver failure (cirrhosis ) b/c they can develop esophageal varices which can rupture with an OG/NG tube

caused by excess histamine release

anaphylaxis

2 main problems associated with anaphylaxis

1. vasodilation (hTN) | 2. bronchoconstriction (wheezing)

tx for anaphylaxis (4)

1. subcutaneous epinephrine 2. bronchodilators (beta 2 agonists) 3. histamine blockers 4. steroid (100 mg hydrocortisone)

refers to decrease in blood flow to a bodily compartment due to an increase of pressure inside the compartment and which compressed blood vessels

compartment syndrome

tx for compartment syndrome

surgical fasciotomy

causes of compartment syndrome (3)

1. fracture 2. infiltrated IV 3. tight cast

sudden onset of bradycardia and/or hypotension

vagal response

when are vagal response commonly seen?

1. CO2 insufflation for laparoscopic sx 2. eye surgery 3. abdominal or uterine surgery

if vasopressor therapy is not as effect what should you consider?

stress dose of steroids

what steroids are used for "Stress dose"

solu-medrol or solu-cortef

hypoventilation that is caused by the pain of breathing

abdominal splinting

how to prevent splinting? (3)

1. dosing pain med 2. supplementing anesthetic w/ nerve blocks 3. local anesthetic injection at the surgical site

OR Concepts Flashcards

(68 cards)