Cardiac Assessment Cardiac Assessment in the OR: in the OR: Troubleshooting when coming off Troubleshooting when coming off bypassbypass

Kimberly D. Milhoan, MDKimberly D. Milhoan, MDAssistant Clinical Professor, University of Texas Health Assistant Clinical Professor, University of Texas Health Science Center, San Antonio, TXScience Center, San Antonio, TX

2011 Cardiac Critical Care Course2011 Cardiac Critical Care CourseKathmandu, NepalKathmandu, NepalOctober 17, 2011October 17, 2011

Anesthetic Order of Anesthetic Order of EventsEvents

Cardiac Bypass:Cardiac Bypass: Pre-operative evaluationPre-operative evaluation Sedation outside ORSedation outside OR Induction in ORInduction in OR Pre-bypassPre-bypass Initiation of bypassInitiation of bypass Maintenance of bypassMaintenance of bypass Re-warmingRe-warming Separation from bypassSeparation from bypass Post-bypassPost-bypass (Extubation)(Extubation) Transport to ICUTransport to ICU

Maintenance of BypassMaintenance of Bypass

ASDASD– Temperature Temperature

maintainedmaintained– Heart fibrillatedHeart fibrillated

Most other lesionsMost other lesions– Temperature cooledTemperature cooled– If intra-cardiac, If intra-cardiac,

aortic cross-clamp aortic cross-clamp placed and placed and cardioplegia givencardioplegia given

Re-warming phaseRe-warming phase

Target temperature: 36.5 – 37.5 CTarget temperature: 36.5 – 37.5 C– Use “Bair hugger,” warming blanket, Use “Bair hugger,” warming blanket,

humidified circuit and/or Humidiventhumidified circuit and/or Humidivent Consider redose of sedation, muscle Consider redose of sedation, muscle

relaxant, narcoticrelaxant, narcotic Give H1- and H2-blockers and anti-Give H1- and H2-blockers and anti-

arrhythmics (magnesium sulfate or arrhythmics (magnesium sulfate or lidocaine)lidocaine)

Start vasoactive drips, e.g. milrinone Start vasoactive drips, e.g. milrinone 50 mcg/kg bolus; 0.3-0.7mcg/kg/min50 mcg/kg bolus; 0.3-0.7mcg/kg/min

Re-warming phaseRe-warming phase

Prior to removal Prior to removal of cross-clampof cross-clamp– EchocardiographeEchocardiographe

r looks for r looks for intracardiac airintracardiac air

– Begin ventilationBegin ventilation Pulmonary toilet: Pulmonary toilet:

suction, suction, (albuterol)(albuterol)

Re-warming phaseRe-warming phase

After removal of cross-clampAfter removal of cross-clamp– Spontaneous cardiac activitySpontaneous cardiac activity– If not, check ABG and electrolytesIf not, check ABG and electrolytes– If ventricular fibrillation, direct cardiac If ventricular fibrillation, direct cardiac

defibrillation; consider more anti-defibrillation; consider more anti-arrhythmicsarrhythmics

– If ST-segment depression/elevation, look If ST-segment depression/elevation, look for intracardiac airfor intracardiac air

– If non-sinus rhythm, consider cardiac If non-sinus rhythm, consider cardiac pacingpacing

Re-warming phaseRe-warming phase

Check ABG and electrolytesCheck ABG and electrolytes– Correct base deficit: Vd x base deficit x wt Correct base deficit: Vd x base deficit x wt

in kg in kg give half of calculated dose in meq give half of calculated dose in meq (Vd: 0.4 in infants, 0.3 in (Vd: 0.4 in infants, 0.3 in children/adolescents, 0.2 in adults)children/adolescents, 0.2 in adults)

– Correct calcium (approximately 40 mg/kg)--Correct calcium (approximately 40 mg/kg)--give calcium after cross-clamp removal and give calcium after cross-clamp removal and patient is warmer than 34 degrees Celsiuspatient is warmer than 34 degrees Celsius

– Correct potassium (1 meq/kg over 10 Correct potassium (1 meq/kg over 10 minutes if <3.0)minutes if <3.0)

Criteria for Separation Criteria for Separation from Bypassfrom Bypass Patient warm (36 degrees Celsius)Patient warm (36 degrees Celsius) ABG and electrolytes normalABG and electrolytes normal Hematocrit adequateHematocrit adequate Sinus rhythm at appropriate rateSinus rhythm at appropriate rate Effective ventilationEffective ventilation Appropriate vasoactive dripsAppropriate vasoactive drips Adequate repairAdequate repair

Separation from Separation from BypassBypass After usually at After usually at

least 10 minutes least 10 minutes of cardiac of cardiac activity, allow activity, allow heart to fill and heart to fill and eject (partial eject (partial bypass) to assess bypass) to assess cardiac function, cardiac function, hemodynamicshemodynamics

Separation from Separation from Bypass:Bypass:TroubleshootingTroubleshooting Philosophies:Philosophies:

– Consider one problem, one solution at a timeConsider one problem, one solution at a time– Use direct observation of heart/surgical fieldUse direct observation of heart/surgical field– Use all monitorsUse all monitors– Consider where you are in procedureConsider where you are in procedure– Consider returning to previous conditionConsider returning to previous condition– Consider potential post-operative risks of repair Consider potential post-operative risks of repair

undertakenundertaken

Separation from Separation from Bypass:Bypass:TroubleshootingTroubleshooting On either partial bypass or after removal On either partial bypass or after removal

from bypass:from bypass:– Repair or rhythm issuesRepair or rhythm issues– Hypovolemia (low BP & low CVP): give volumeHypovolemia (low BP & low CVP): give volume– LV failure (low BP & normal/high CVP): afterload LV failure (low BP & normal/high CVP): afterload

reduction, inotropesreduction, inotropes– RV failure (low BP, high CVP): pulmonary RV failure (low BP, high CVP): pulmonary

vasodilator, assess oxygenation/ventilation and vasodilator, assess oxygenation/ventilation and acid/base statusacid/base status

– Vasodilation (low BP, normal/low CVP): consider Vasodilation (low BP, normal/low CVP): consider increasing hematocritincreasing hematocrit

ResourcesResources

Andropoulos DB, Stayer SA, and Russell IA. Andropoulos DB, Stayer SA, and Russell IA. Anesthesia for Congenital Heart DiseaseAnesthesia for Congenital Heart Disease. . Malden: Futura, 2005.Malden: Futura, 2005.

Lake CL and Booker PD. Lake CL and Booker PD. Pediatric Cardiac Pediatric Cardiac Anesthesia, 4Anesthesia, 4thth edition edition. Philadelphia: . Philadelphia: Lippincott, Williams, & Wilkins, 2005.Lippincott, Williams, & Wilkins, 2005.

Morgan, G. Edward et al. Morgan, G. Edward et al. Clinical Clinical AnesthesiologyAnesthesiology, 3, 3rdrd ed. New York: Appleton & ed. New York: Appleton & Lange, 2002.Lange, 2002.