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60 Cards in this Set
- Front
- Back
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What does a sudden drop of the capnography waveform but not to zero indicate?
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leakage or partial obstruction of the airway
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What does an exponential decrease of the capnography waveform indicate?
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increase alveolar dead space such as a PE or cardiac arrest
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When during the cardiac cycle is the pulse ox saturation measured?
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it measures the difference between the background absorption during diastole and the peak absorption during systole
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When do you get a very low or absent pulse with pulseox?
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hypotension, hypothermia, hypovolemia
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What conditions lead to a pulse ox reading of 85%?
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met-hgb, indocyanine green
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what are the typical pulse ox readings for carboxyhemoblobin?
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normal
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How can anemia affect the pulse ox values?
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pulse ox doesn't work well with hgb of 3-5
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How does RV failure or tricuspid regurgitation affect pulse ox readings?
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can produce false values
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What are the magnetic properties of oxygen and the anesthetic gases?
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oxygen is paramagnetic(attracted to magnetic field), volatiles are diamagnetic(repealed by magnetic field)
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What situation leads to a underdampened arterial waveform?
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small tubing(internal diameter<1.5mm), long tubing(>1.5m long), stiff tubing, big catheter(ie 18g in radial artery)
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What situations lead to an overdampened arterial waveform?
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high viscosity, soft, high compliance tubing, bubbles in the system
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How do you convert cm variations in arterial transducer height into mmHg pressure variations?
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1.36cm H20=1mmHg
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How does systolic and diastolic pressure change based on distance from the heart?
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The further from the heart the higher the systolic and the lower the diastolic
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What happens if the blood pressure cuff is too small or loosely wrapped?
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Blood pressure readings are too high
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What risk is associated with brachial artery cannulation for arterial pressure monitoring?
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thrombosis(10-17%)
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How does size of the cannula and duration of cannulation affect incidence of hand ischemia with radial artery cannulation?
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it may not influence hand ischemia
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What is a complication of superficial temporal artery cannulation in children?
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cerebral emboli via the carotid artery system
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What are contraindications to radial artery cannulation?
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local infection, pre-existing ischemia to the hand, raynauds phenomena
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How can you remember the CVP wave components?
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think of the following sequence: atrial contraction, relaxation, filling, emptying; or All College, Exams, Vary Yearly
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When do you lose the Awave?
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afib
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when do you see giant A waves?
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atrial contraction against a closed tricuspid valve(heart block, nodal rhythms, tricuspid stenosis)
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What does the C wave result from?
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corresponds to ventricular systole and results from tricuspid valve closure
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What does the V wave represent and when do you see an increased size of the wave?
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right atrium begins to fill; tricuspid regurg
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What are the most frequent causes of elevated CVP?
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fluid overload, right heart failure, light anesthesia
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When is there good correlation between CVP and PCWP?
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when there is good LV function, no wall motion abnormalities, PCWP<18
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What are causes of increased pulmonary vascular resistance?
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pain, hypoxia, hypercarbia, drugs, acidosis, pulmonary emboli, pulmonary edema, COPD, mitral valve disease
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When are PA catheters useful?
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major surgery with major fluid shifts in the presence of severe LV dysfunction, cardiac failure, pulmonary htn, or cor pulmonale
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When the aorta is to be cross clamped when should you consider use of a PA catheter?
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helps detect LV failure in response to cross clamping which is difficult to predict in the presence of mild to mod LV dysfxn
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What are normal intracardiac presssures obtained with a PA catheter?
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RA 1-5mm Hg; RV 15-30/1-5mmHg; PA 15-30/5-15mmHg with mean of 10-20; PCWP 5-12mmHg
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How does PCWP relate to PADP?
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PADP should be 1-3mmHg higher than PCWP; PCWP should never be higher than PADP when it does occur the balloon is overinflated and needs to be deflated immediately
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If a and v waves are present on the pulmonary catheter tracing what should you worry about?
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spontaneous wedging of the PA catheter and increased risk of PA rupture or infarction(small a and v waves are common when the balloon is inflated)
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What can cause large a waves on the PAOP waveform?
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mitral stenosis, complete heart block, atrial myxoma, early acute heart failure
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What can cause large v waves on the PAOP waveform?
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mitral regurg, mitral stenosis, CHF, VSD
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How can PA catheter affect the hearts conducting system?
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can cause RBBB; may want to place temporatry pacer in a patient with preexisting LBBB
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What are contraindications of a PA catheter?
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absolute: mechanical heart valves; relative: recently inserted transvenous pacer; bifascicular heart block, coagulopathy, frequent dysrrhythmias, hx of pulm stenosis
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How should cardiac output be measured?
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end expiration with 10cc of room temp injectate;
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How is thermodilation CO obtained?
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use cold as an indicator and measure the concentration of cold as the indicator in the PA after mixing has occured in the RV
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When is thermodilution CO inaccurate?
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AF, TR, intracardiac shunts,
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How does a decreased amount of cold indicator affect CO measure by thermodiluation technique?
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artifically high value
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In a healthy patient how does PCWP, LAP, LVEDP, LVEDV relate
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PCWP=LAP=LVEDP=LVEDV
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When is PCWP>LVEDP?
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PEEP, mitral stenosis, left atrial myxoma where there can be a ball valve effect preventing proper emptying of atrium
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how do you treat low CO?
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optimize preload, optimize afterload, start inotrope
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When is PCWP<LVEDP?
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LV is noncompliant, LVEDP>25mmHg, when AI leads to premature closure of mitral valve
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What are causes of increased capillary leak that can lead to pulmonary edema?
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aspiration, ARDS(sepsis, DIC, massive blood transfusion), burn, neurogenic
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What are signs associated with cardiogenic pulmonary edema?
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elevated PCWP, bibasillar rales, patchy infiltrates and pink frothy sputum
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What are signs associated with noncardiogenic pulmonary edema?
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PCWP generally not elevated, bibasillar rales
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How can you do a modified V5 lead when you only have 3 leads?
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right arm electrode in normal position place left arm electrode in V5 position(5th intercostal space ant axillary line) and L leg electrode in normal position
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What leads can evaluate the RCA?
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II, III, aVF(RA, RV)
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What leads can evaluate the LAD?
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V3-5(ant lat LV)
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What leads evaluate the circumflex?
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I, aVL(lateral LV
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How do you determine if there is LVH on EKG?
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add up S in V1 and R in V5 if they add up to >35mm (each box is 1mm)there is probably LVH
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How do you determine if there is atrial hypertrophy on EKG?
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if p wave in V1 is greater than 3mm or biphasic you should suspect atrial hypertrophy
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What is frequency and wavelength?
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frequency=number of cycles/s; wavelength=distance traveled by sound during one cycle
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How does the frequency and wavelengh change if an object is moving toward the observer?
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wavelength is shorter and frequency is higher
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How does the frequency and wavelengh change if an object is moving away from the observer?
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wavelength is longer frequency is lower
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What factors increase frequency on EEG?
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hyperoxia, hypercarbia(mild), hypoxia(initial), sz, barbs, valium, inhalational agents<1MAC, N2O, ketamine
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What factors decrease the frequency and decrease the amplitute on EEG?
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hypothermia, hypocarbia(mod to severe), hypoxia(mild), barbs-moderate dose, etomidate, narcotics, inhalational agents>1MAC
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What factors decrease the frequency and decrease the amplitude on EEG?
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hypoxia-severe, hypercarbia severe, hypothermia, hypotension, barbs large doses
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What factors can cause electrical silence on EEG?
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brain death, severe hypothermia, severe hypoxia, barb-coma dose, isoflurane 2MAC
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What patients cannot be taken into the MRI scanner?
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pacemaker or aneurysm clips
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