OR Concepts Flashcards
Where are baroreceptors located?
- Carotid sinuses
- Aortic arch
Carotid sinus
Contains baroreceptors that adjust heart rate to maintain normal cardiac output/blood pressure
Carotid body
Cluster of cells that PRIMARILY sense hypoxia and stimulate faster respirations
Possible causes of a stroke
- Blood clot “Ischemic stroke” 2. Intracranial hemorrhage “Hemorrhagic stroke” 3. Prolonged hypotension (inadequate brain perfusion) 4. Hypertension This leads to stress on the walls of blood vessels and is associated with intracranial hemorrhage
Pulmonary embolism
If the DVT becomes dislodged from the legs, it can move to the heart and lungs (at which point it becomes defined as a pulmonary embolism), which is a life threatening emergency
Percentage of ICF?
65%
Edema
When the patient builds up excess interstitial fluid, it is referred to as “edema” (swelling)
Pulmonary edema
Pulmonary edema refers to a buildup of excess fluid in the alveolar spaces, and it is usually causes by some degree of heart failure (which causes some blood to back up into the lungs)
Preload
Preload refers to the volume of blood that is returning to the right ventricle and available for the heart to pump on the next contraction
Afterload
Afterload refers to the resistance the left ventricle has to pump against can lead to left ventricular hypertrophy Afterload refers to the amount of resistance the left ventricle has to pump against It is proportional to the level of vasoconstriction in the body Vasoconstriction = high afterload Vasodilation = low afterload
How do you measure preload?
An anesthetist can measure preload by monitoring central venous pressure (CVP) CVP is the blood pressure within the superior vena cava (normally 5-12mmHg), and this can be only be measured if an anesthetist places a central line (which is an IV catheter in a large “central” vein (internal jugular, subclavian, etc)
Transmural pressure
Transmural pressure refers to the difference in pressure between two sides of a wall or equivalent separator
Systemic vascular resistance
SVR refers to resistance that the left ventricle must pump against, and it is affected by peripheral arterial vascular tone Arterial vasoconstriction = high SVR, while arterial vasodilation = low SVR
Pulmonary vascular resistance
“PVR” refers to the resistance that the right ventricle must pump against, and is affected by the vascular tone in the pulmonary arteries Pulmonary artery vasoconstriction = high PVR, while pulmonary artery vasodilation = low PVR PVR is normally much lower than SVR, because there is less resistance in the pulmonary circulation
Cautery pen
A cautery pen (“bovie”) is a surgical cutting device that simultaneously cuts tissue and burns/coagulates blood vessels by sending electricity to the surgical area (and to the body)