ALTERATIONS OF CARDIAC FUNCTION CONGENITAL HEART DEFECT

Transition from fetal to pulmonary circulation How does the circulation during fetal life differ from that of the neonate? What leads to this transition? How do the changes of pressures and resistance within the heart effect the foramen ovale, ductus venosus, and ductus arteriosus? Differences for the child in cardiovascular functioning  Why is the child at greater risk of CHF?  Why does the child’s heart beat faster?  Hct, Hgb and pulse ox concentrations appropriate for age needed for adequate oxygen transport  Cyanosis indicates hypoxemia to bone marrow producing RBC’s to Hgb (polycythemia)  Polycythemia: Hgb  20 g/dL & Hct  55%-60%  What is the danger of Severe Hypoxemia? Leads to bradycardia cardiac arrest BASIC PHYSIOLOGY  WHAT IS THE HEART: Heart is a pump sending blood throughout the body  WHAT IS CARDIAC OUTPUT?Heart must maintain adequate CARDIAC OUTPUT: volume of blood ejected by the heart in a 1 minute  Cardiac output determined by multiplying the heart rate by the stroke volume  WHAT IS STROKE VOLUME: amount of blood ejected by the heart in any one contraction PHYSIOLOGY CONTINUED  WHAT IS STROKE VOLUME INFLUENCED BY: 1. Preload: volume of blood returning to the heart or the circulating blood volume; measured by CVP 2. Afterload: resistance against which the ventricles must pump when ejecting blood (ventricular ejection); measured by hemodynamic monitoring via arterial blood pressure 3. Contractility: ability of the cardiac muscle to act an efficient pump; difficult to measure clinically WHAT KIND OF TESTING IS DONE TO DIAGNOSE? Cardiac Catherization  Imaging study using radiopague catheters  placed in a peripheral blood vessel  advanced into the heart 1. To measure pressures and oxygen levels in heart chambers 2. To visualize heart structures 3. To see blood flow patterns PREOP NURSING CARE CARDIAC CATHERIZATION WHY NEED Accurate hgt and wgt WHY IS History of allergies to iodine important? WHAT HAPPENS IF THE CHILD HAS Severe diaper rash WHY Mark pulses: dorsalis pedis, posterior t ibial WHY Baseline pulse ox PREOP CARDIAC CATH HOW TO Prepare child: schoolage/adolescent Preop receive what drugs? WHAT DIET PREOP AND WHY? POSTOP NURSING CARE CARDIAC CATHERIZATION  Assess pulses below cath site for equality and symmetry  Normal for first few hours for pulse distal to cath site to be weaker, but should increase in strength  Assess temperature and color of affected extremity  Coolness/blanching may indicate arterial obstruction  VS q 15 min  watch for dysrhythmias/bradycardia POSTOP NURSING CARE CARDIAC CATHERIZATION WHY CHECK BP WHY Check dressing Check I&O both IV and po Keep affected extremity straight 4-6 hours after venous cath and 6-8 hours after arterial cath (parents may hold child) May use sandbag at site POSTOP HOME CARE CARDIAC CATH Pressure dressing INSTRUCTIONS What is done to Cover site? Bathing instructions? What observations are made for complications? What activity instructions? What is used for pain? POSTOP CARDIAC CATH SITUATION Tommy, a 4 year old with Tetralogy of Fallot returns from catherization laboratory. He has vomited, his mother calls you to the bedside to tell you that he is bleeding. You arrive to find Tommy crying and sitting up in a puddle of blood. The first thing you do is: ANSWERS TO POSTOP CATH SITUATION 1. Increase the rate of his IV fluids 2. Give an antiemetic and keep Tommy NPO 3. Call the cardiologist 4. Lie Tommy down, remove the dressing and apply direct pressure above the catherization site ANSWERS TO SITUATION GENERAL S & S of CHD in INFANTS AND CHILDREN  INFANTS:  Dyspnea  Difficulty feeding  Stridor, choking spells  Pulse rate over 200  FTT  Heart murmurs  Frequent URI’s  Anoxic attacks  CVA  CHILDREN:  Exercise intolerance  Increased BP  Poor physical development  Heart murmurs  Cyanosis  Recurrent URI  Clubbing fingers/toes  squattin