Cardiology.docx

Anesthesia is basically a stress test Ensure pts are optimized prior to procedures and ID "needle in a haystack" of bad cardiac events Surgical types - Emergent surgery = risk of life or limb in 6 hours - Elective surgery - Urgent surgery = risk of life or limb in 24 hours Cardiovascular...

Anesthesia is basically a stress test Ensure pts are optimized prior to procedures and ID "needle in a haystack" of bad cardiac events Surgical types - Emergent surgery = risk of life or limb in 6 hours - Elective surgery - Urgent surgery = risk of life or limb in 24 hours Cardiovascular anatomy - Heart roughly the size of fist - Female hearts are smaller than male hearts - **Mediastinum** = connective tissue lined compartment bordered by the lungs, sternum, thoracic vertebral bodies - Contains heart, aorta, PA, SVC, IVC, trachea, esophagus, thoracic duct, thoracic lymph nodes - RV is most anterior structure - **Pericardium** = fibrous outer layer and inner serous layer - Fibrous layer affixes heart to mediastinum - Serous layer consists of parietal and visceral layer - **Epicardium** = outermost layer where right and left coronary arteries lie - **Myocardium** = muscle middle layer of heart - **Endocardium** = innermost layer that lines the heart Heart chambers - RA RV - Received deoxygenated blood from the SVC, IVC, and coronary sinus - Coronary sinus receives blood from cardiac veins/drains myocardium - LA LV Heart valves - AV (atrioventricular -- tricuspid and bicuspid/mitral valves) -- S1 sounds - Semilunar (pulmonic and aortic) valves -- S2 sounds **Cardiac output** = volume of blood ejected from heart each minute (SV x HR) - SV = volume of blood ejected from heart each beat - CO varies based on preload, contractility, and afterload **Ejection fraction** = % of volume ejected during each beat **Preload** = volume of blood remaining in the ventricles at the end of diastole **Contractility** = ability of the muscle cells to stretch and recoil **Afterload** = pressure the heart has to work against to eject blood Cardiac base and apex - Heart rotates during fetal development so base is at top and apex at bottom - **Cardiac** **base** - Formed by the posterior surface of the heart - Refers to the superior aspect of the heart where the great vessels enter - Located at right and left 2^nd^ ICS - **Cardiac** **apex** - Most inferior, anterior, and lateral heart - Formed by the tip of the LV - **Palpation of PMI (point of maximal impulse)** - not always palpable - diameter is normally 1-2.5 cm - at cardiac apex -- need to know - Located at 5^th^ ICS just left to the medial to the left MCL - Can shift secondary to a disease process -- usually indicative of a chronic problem e.g. shifted right due to RVH in COPD **Cardiac conduction** - SA node located near SVC - AV - Bundle of His -- only direct connection for electrical impulses to move from atria to ventricles - Bundle branches **Heart sounds** -- know what's normal/abnormal and what heart sounds are truly problematic (i.e. aortic stenosis and cardiac tamponade - S1-S2 sounds are normal - In kids and adolescents and younger/healthy adults, S3 is normal due to rapid deceleration of blood against the ventricular wall - In most adults, S3 and S4 are pathologic - S3 = Systolic heart failure or ischemia - S3 gallop - Abrupt deceleration of inflow across mitral valve - S4 = Diastolic heart failure - Immediately precedes S1 - Increased LVED stiffness - Represents ventricular dysfunction and decreased compliance - Can be seen in acute MI - HEART SOUND SPLITTING DEFINED???? - S1 splitting - S1 = closure of mitral and tricuspid valves - Normal finding - Best heard at lower left sternal border - Mitral sound loudest - No change in respiration - S2 splitting - S2 = aortic and pulmonic valves closing - S2 splitting on inspiration - Aortic valve closure precedes pulmonic valve closure - Aortic sound louder - Best heard at 2-3^rd^ ICS near sternum **Heart murmur** = distinct heart sounds attributed to turbulent blood flow - Graded by intensity (best to worst 1-6) and can be indicative of valvular disease - **Innocent/functional murmur** due to increased blood flow through the heart (e.g. anemia, fever, pregnancy, hyperthyroidism) Pre-Op Cardiac Assessment - Who gets preop EKG? It depends on facility - Guidelines between AHA, ACC, Revised Cardiac Risk Index (RCRI) - Risk of MI increases with proximity to MI Patient History - Pre-existing heart disease (HTN, ischemic heart disease, valvular dysfunction, arrhythmias, conduction abnormalities) - Disease severity, stability - Comorbidities (DM, PVD, COPD, obesity, smoking, etc) - **Functional capacity** = METS (metabolic equivalent) = minimum 4 METs recommended for surgical optimization - 2 flights of stairs without getting SOB - Walking 4 blocks at a brisk pace without getting SOB - Surgical procedure? Elective vs emergent? **Hypertension** - Patients with baseline hypertension are more likely to develop intraoperative hypotension - Normal SBP \140 DBP\>90 - Uncontrolled SBP\>180 DBP\>110 - If pt is in uncontrolled, justify why you're proceeding with surgery - Consider white coat hypertension - Essential/idiopathic hypertension = 90% of cause of HTN - Complications of HTN MI, end organ damage, AKI, etc **Ischemic Heart Disease/MI** - Elderly women and diabetics present atypically - Risk factors = advanced age, smoking DM, HTN, pulmonary disease, previous MI, LV dysfunction, PVD - Signs and symptoms requiring further evaluation = fatigue, angina, palpitations, syncope, dyspnea - Preop evaluation objective = determining the severity, progression, and functional limitations **Angina** = substernal discomfort - **Stable** - brought on by exertion - can be relieved by rest/nitroglycerin in \30 mins - Exhibits ST or T wave changes - **Unstable angina is associated with the highest risk of perioperative MI** - Newly developed/progressively worsening **Heart failure** - Symptoms = CHF, pulmonary edema, paroxysmal nocturnal dyspnea - Clinical findings - S3 gallop, rales, tachypnea, resting tachycardia, JVD, peripheral edema - HFpEF = preserved ejection fraction - EF greater than or equal to 50% - Tend to do better than HFrEF patients - HRrEF = reduced ejection fraction - EF \girls - Often present at birth - Pectus carinatum - Pigeon chest deformity where breast bone and ribs are pushed outward - Can be asymmetrical - Affects boys\>girls - Can be associated with scoliosis Assessment of pulses - Rate, rhythm, contour, amplitude - Pulse wave amplification - Arterial pulse changes as it travels from aorta to peripheral arteries - MAP decreases and SBP increases - Carotid pulse is best to evaluate heart - Distal pulse is best to evaluate vessels - Contour is used for noninvasive CO measurement - Amplitude = how strong or forceful a pulse is - Normal findings - Carotid = smooth, rapid upstroke with a gradual downstroke briefly interrupted by the pulse peak - Radial = strong, regular, and asymmetrical Pulse abnormalities - Pulsus bisferiens - Double pulse - Seen in AI or hypertrophic cardiomyopathy - Pulsus bigeminus - Alteration in pulse amplitude that follows a ventricular premature beat - Pulsus alterans - Regular alternating pulse amplitude due to alternating LV contractile force - Seen in severe LV decompensation and cardiac tamponade - Pulsus parvus et tardus - Small and slow rising - Represents a delayed systolic peak due to obstruction of LV ejection - Seen in AI Orthostatic hypotension = postural hypotension - BP falls when standing up or stretching - 20mmHg drop in SBP or 10mmHg drop in DBP within 3 minutes of standing - Caused by blood pooling in the lower extremities Measuring JVD - Find highest point of oscillation in the internal jugular vein and measure the distance above the sternal angle - If no jugular pulsation is noted, it may lie below the level of the sternum - JVP \> 3 cm is indicative of elevated CVP Carotid auscultation - Pt is supine or sitting - Have pt breathe in and hold - Place bell of stethoscope over carotid artery - Listen for bruit (i.e. blowing sounds) - Bruit - Primarily caused by atherosclerotic luminal stenosis - Other causes = tortuous carotid artery, external carotid arterial disease, aortic stenosis, hypervascularity of hyperthyroidism, external compression from thoracic outlet syndrome - Do not correlate with clinically significant underlying disease????? - Cardiac murmurs can be transmitted to carotids perform a complete precordial exam - Thrills of aortic stenosis are transmitted to the carotid arteries from the suprasternal notch or 2^nd^ IC Palpation of heart - Normal PMI at 5^th^ ICS just medial to MCL 2.5 cm in diameter - Abnormal - Dextrocardia -- PMI on right side of chest - Cardiomegaly -- lateral shift of PMI - LVH -- PMI \>2.5 and shifted lateral to MCL - RVH (seen in COPD) -- PMI shifts to xiphoid or epigastric area (right/down) - Ascites, pregnancy, abdominal distention -- displace apex up and to left Heart murmurs - Timing in cardiac cycle - Intensity: grade 1-grade 4 - Pitch: high, medium, low - Pattern: crescendo, decrescendo, crescendo-decrescendo - Quality: click, snap, musical, blowing, harsh, rumbling - Location: location of maximal intensity - Radiation: flow (sound is transmitted in direction of blood) Abnormality Location Timing Description ----------------------------- ---------- -------- ------------- Aortic stenosis AI Mitral stenosis Mitral regurgitation Mitral valve prolapse Hypertrophic cardiomyopathy - Peripheral vascular exam - Edema - Pulses - Cardiac tamponade - Increased intrapericardial pressure causes impaired diastolic filling - Causes - Symptoms - Diagnosis -- echocardiogram is the best method - Treatment = paracentesis, pericardial window