Cardiovascular Management during Anesthesia

Cardiovascular Managementduring Anesthesia Dong Soo Kim, M.D. aruma@khu.ac.kr www.nopain365.com

꽃- 김 춘 수 –내가 그의 이름을 불러주기 전에는 그는 다만 하나의 몸짓에 지나지 않았다.내가 그의 이름을 불러주었을 때 그는 나에게로 다가와서 꽃이 되었다.내가 그의 이름을 불러준 것처럼 나의 이 빛깔과 향기에 알 맞는 누가 나의 이름을 불러다오.그에게로 가서 나도 그의 꽃이 되고 싶다.우리들은 모두 무엇이 되고 싶다.나는 너에게 너는 나에게 잊혀지지 않는 하나의 의미가 되고 싶다.

One of the primary responsibilities of an anesthesiologists is to act as a ‘guardian’ for the anesthetized patient during surgery.

General Considerations of Anesthetic Patients • NPO • Anesthetics ; unconscious state • Surgical manipulation • Bleeding • Sympathetic tone ↓, ↑ • Muscle relaxation

Standards for Basic Anesthetic Monitoring • Standard ⅠQualified anesthesia personnel shall be present in the room throughout the conduct of all general anesthetics, regional anesthetics and monitored anesthesia care.(Approved by the ASA House of Delegates on Oct. 21, 1998)

Standards for Basic Anesthetic Monitoring • Standard ⅡDuring allanesthetics, the patient’s oxygenation, ventilation, circulation, and temperature shall be continually evaluated.(Approved by the ASA House of Delegates on Oct. 21, 1998)

Monitoring during Anesthesia • BP, heart rate • ECG • CVP • Pulse oximetry • Capnography • Urine output • Temperature • BIS (bispectral index) • PNS (peripheral nerve stimulator)

Standards for Monitoring of Circulation • Objective :To ensure the adequacy of the patient’s circulatory function during all anesthetics. • Methods : • ABP & HR at least every 5 min • ECG continuously displayed • 1, 2, and at least one of the following ; - Palpation of a pulse - Auscultation of heart sounds- Ultrasound peripheral pulse monitoring, or pulse oximetry

Monitoring of CV Function • Primary physical examination- inspection, palpation and auscultation by anesthetists - reliability of electronic monitoring ↑ • Dependence of electronic monitoring ↑→ tendency to slight physical examination

Stethoscopy Precordial stethoscope Esophageal stethoscope

Pulse Rate Monitoring • More important than HR, in terms of perioperative hemodynamic monitoring • Pulse deficit (PR 〈 HR)- atrial fibrillation- electromechanical dissociation (EMD)- cardiac tamponade- extreme hypovolemia • Useful in distinguishing artifactual ECG signals and erroneous HR from important real cardiac events

Heart Rate Monitoring • The simplest and least invasive form of cardiac monitoring • ECG : detect R wave and measure R-R interval • Display a updated number every 5-15 sec • Electrical interference from electrosurgical unit

ABP Monitoring • Stephen Hales (1677-1761) : first animal experiment to measure BP • Fundamental CV vital sign reflecting force that derives perfusion of the body • Most important determinant of LV afterload, the workload of heart • Indirect Riva-Rocci cuff deviceDirect arterial cannulation & pressure transduction

Indirect Measurement of ABP

Automated Intermittent Measurement of BP

Percutaneous RadialArterial Cannulation • Advantages :- continuous real-time monitoring- easy sampling of arterial blood • Allen test : to assess the adequacy of collateral circulation

Hemodilution Technique using Radial Arterial Cannulation

Intraoperative Monitoring of ECG • All patients should have intraoperative monitoring of ECG • No contraindications • Useful for detection of - arrhythmias- myocardial ischemia- conduction abnormalities- pacemaker malfunction- electrolyte disturbances

Perioperative Incidence of Arrhythmias • Overall incidence during op ; 29.9% • Pre-op cardiac diseases ; - yes : 51.4% - no : 19.9% • 195 arrhythmias in 95 patients ;- junctional rhythm in 63 patients- wandering atrial pacemaker in 43 patients - bradycardia, tachycardia- ventricular ectopic beats

Arrhythmias during Anesthesia • Arrhythmias are more likely with;- hypoxemia and hypercapnia- deep inhalation anesthesia, esp. halothane- surgical stimulation and light anesthesia- electrolyte imbalance, esp. potassium- pre-existing cardiac disease- use of catecholamine as vasopressors- central venous or pulmonary art. catheterization

Lead Selection for Monitoring of ECG • Lead selection : diagnostic sensitivity of ECG • Lead II : - greatest P wave voltages - diagnosis of dysrhythmia- detection of inferior wall ischemia

Central Venous Pressure Monitoring • One of cardiac filling pressure monitoring • Capacity of vascular systemVolume of blood in vascular systemPumping action of right ventricle • CVP approximates right atrial pressure • Indications of CV catheterization :- cvp monitoring- fluid management ; hypovolemia- total parenteral nutrition(TPN)- poor peripheral veins- aspiration of air emboli

Central Venous Catheterization • Preferable sites : - basilic vein - jugular vein(Rt. Internal)- subclavian vein • Location of catheter tip - junction of SVC and RA- level of tracheal carina(T4-T5) • Venous pressure should be measured during end-expiration

Reference Point ofCVP ICS ; intercostal space, MAL ; midaxillary line

Clinical Considerations of CVP • Normal level : 0 - 8 cmH2O • Increased by ; - raised intrathoracic pressure ; IPPV- impaired cardiac function- circulatory overload- vasoconstriction • Decreased by - reduced venous return ; hypovolemia- reduced intrathoracic pressure

Pulse oximetry

Capnography • Valuable monitor of the pulmonary, CV & anesthetic breathing systems • Determination of ETCO2 conc. to confirm adequate ventilation & circulation

Urinary output • Reflection of kidney perfusion & function • Indicator of renal, CV, and fluid vol. status • Bladder catheterization ; • - only reliable method of monitoring urinary output • Oliguria ; < 0.5 mL/kg/h

‘제주 야생마’ 양용은, 골프 황제 꺾다 2007 HSBC 챔피언쉽 골프 토너먼트에서 우승한 양용은 선수

Causes of Hypotensionduring Anesthesia • Excessive premedication • Influence of potent therapeutic drugs • Overdose of general anesthetics • Vascular absorption of local anesthetics • Spinal and epidural anesthesia • Hemorrhage • Surgical maneuvers • Change in position or moving the patient • Cardiovascular disease • Septic shock • Incompatible transfusion • Anaphylactic reactions

Influence of Premedication &Potent Therapeutic Drugs • Opioids ; - depress the vasomotor center - vasodilating action - reduce ability to compensate for circulatory stress (hemorrhage, trauma) • Opioids + barbiturates (or diazepam) ; incidence of hypotension ↑ • Steroids, antihypertensives, beta-blockerscalcium channel blockers

Causes of Hypotension during Anesthesia • Excessive premedication • Influence of potent therapeutic drugs • Overdose of general anesthetics • Vascular absorption of local anesthetics • Spinal and epidural anesthesia • Hemorrhage • Surgical maneuvers • Change in position or moving the patient • Cardiovascular disease • Septic shock • Incompatible transfusion • Anaphylactic reactions

Diagram of inhalation anesthesia FGF; fresh gas flow, FI; inspired gas conc. FA; alveolar gas conc., Fa; arterial gas conc.

Overdose of General Anesthetics • Absolute overdose ;- sudden increase in inspired concentration of inhalation anesthetic- intravenous injection of large amount of barbiturate • Relative overdose ; - reduced circulating blood volume- vasoconstriction- hypoalbuminemia

Spinal and Epidural Anesthesia • Disappearance of neural function from SAB ; autonomic activity → pain → temperature → position → motor power → touch sense • Hypotension results from ;- interruption of sympathetic nerve impulses to systemic blood vessels- interruption of baroreceptor reflexes that control blood pressure • Circulatory studies ; TPVR ↓, CO↓ • The higher the level of sympathetic block, - the more profound is the fall in pressure - the less chance for compensatory vasoconstriction in unanesthetized areas

ACS Classes of Acute Hemorrhage ACS ; American College of Surgeons Miller RD. Anesthesia. 2000

Clinical Classification of Hemorrhagic Shock Morgan GE. Clinical anesthesiology. 2006

Estimation of Blood Loss • Suction bottle • Surgical sponges 4X4 sponges :10 g(10 EA) → 100 g(10 EA) • Ring sponges :100 g(10 EA) → 500 g(10 EA)

Surgical Maneuvers • Reflex hypotension-traction on gallbladder, bowel,uterus, mesentery-stimulation of peritoneum, periosteum, joint cavities - afferent impulses ascend via sympathetic phrenic, or vagal pathway ? • Rapid release of increased intra-abdominal pressure • Rapid decompression of a distended urinary bladder • Carotid sinus stimulation - vagal-induced bradycardia & hypotension • Bone cement in THR

Effect of Surgical Traction of Mesentery on Arterial Pressure Abrupt reduction of pulse pressure with traction on the mesentery of the colon of an anesthetized patient

Change in Position or Moving the Patient • Circulation of anesthetized patient is less able to compensate for stress than that of unanesthetized one, particularly in those critically ill. • Positional changes should be accomplished slowly and gently and BP observed throughout

Poorly Tolerable Positions Lateral position Sitting position

Cardiovascular Diseases • Myocardial ischemia / infarction • Multifocal ventricular tachycardia • Embolism- cerebral air embolism during OHS- pulmonary embolism ; fat embolism from fracture sites amniotic fluid emboli during delivery venous air entrainment during craniotomy • Cardiac tamponade • Heart failure • Cardiogenic shock

Acute myocardial infarction • Serious Cx of ischemic heart • disease • Overall mortality rate ; 25% • More than ½ of deaths ; occur within the 1st hour (due to VF) • Immediate Rx : ‘MONA’ • - Morphine ; 2 - 4 mg IV (until pain relieved) • - Oxygen ; 4 - 6 L/min • - Nitroglycerin (sublingual or spray) • - Aspirin ; 160 - 325 mg

Cardiovascular Management during Anesthesia