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Ped Perfusion
Harry Hoerr; Pediatric Perfusion
| Question | Answer |
|---|---|
| Ductus Venosus | Carries well-oxygenated blood from the placenta through umbilical vein, through the liver, to the IVC |
| Foramen Ovale | A hole between the left and right atria that allows much of the blood entering the right atrium via the IVC to enter the left atrium |
| Ductus Arteriosus | Shunt that allows blood from the right ventricle to enter the descending aorta instead of the higher resistance pulmonary circulation |
| How is the fetal circulation beneficial? | Allows for well oxygenated blood from the IVC to preferentially perfuse the brain, coronary circulation, and upper extremites while the lower portion of the body receives blood with a low oxygen content. |
| What usually happens after birth? | Closure of the ductus arteriosus and foramen ovale occurs w/in a few hours after birth. May take weeks or longer. |
| What are some pulmonary precautions in pediatrics? | During the first years, the pulmonary vasculature is highly reactive. A RISE in PA pressure can easily be produced by hypoxemia, hypercarbia, acidosis, or bronchospasm |
| At birth are both ventricles the same size? | Yes. The LV is 2x heavier that the RV at 6 months of age. |
| What are some concerns with the ultrastructure of a neonate heart? | -Lower percentage of contractile proteins. -Incomplete autonomic innervation. -Immature sarcoplasmic reticulum. -Decreased compliance |
| What is the blood volume a <5 kg peds patient? | 76-83 mL/kg |
| What is the blood volume of a 5-10 kg peds patient? | 85 mL |
| What is the blood volume of a 11-20 kg peds patient? | 80 mL/kg |
| What is the blood volume of a 21-45 kg peds patient? | 75 mL/kg |
| What is the blood volume of a >45 kg peds patient? | 70 mL/kg |
| What is the optimal hematocrit during and after CPB on a ped? | Depends: -Temperature on CPB. -Flows. -Venous Saturation. -Type of repair. |
| What is the optimal colloid osmotic pressure for peds on bypass? | Studies have suggested that lower than normal COP may improve renal function during CPB, and that COP must be decreased over 50% to cause significant amounts of fluid to enter the interstitial region. |
| At what weight would you start using 3/8 in tubing? | Above 16 kg |
| What ped oxygenator/reservoir has the lowest prime volume? | Baby Rx (capiox) |
| What ped oxygenator/reservoir has the largest prime volume? | Minimax (medtronic) |
| 1/4 inch tubing puts out how many ml/foot? | 9.65 ml/foot |
| 3/8 inch tubing puts out how many ml/foot? | 21.7 ml/foot |
| 1/2 inch tubing puts out how many ml/foot? | 38.6 ml/foot |
| 5/8 inch tubing puts out how many ml/foot? | 48 ml/foot |
| How is venous cannulation in peds? | Venous cannulation is usualy bicaval |
| What are some other components in ped perfusion? | -Modified ultrafiltration. -Co2 addition (for pH stat). -In-line blood gas monitoring |
| What are normal ped perfusion pressures? | Perfusion pressures as low as 30mmHg are widely accepted. |
| What would you do if a peds patient had hypertension on pump? | Hypertension can often be controlled by the perfusionist using flow rate or by increasing the percent of volatile anesthetic (isoflurane) |
| What are some factors that determine TBW? | -Duration of CPB. -Flow rates. -Oncotic pressure. -Capillary leakage |
| What are some effects of increased TBW in peds patients? | -Pulmonary Edema. -Ascites. -Depressed cardia function (may lead to more edema) |
| When is MUF carried out in a ped patient? | MUF is carried out shortly after the patient is weaned from CPB, before protamine and arterial decannulation. Blood flows retrograde through the aortic cannula and arterial line, through pump head and hemoconcentrator & transfused back into the R atrium |
| When using MUF what is important to remember about clamp position? | -Clamp out arterial filter to keep primed. -Clamp out crystalloid portion of cardioplegia |
| What are some beneficial effects of MUF? | -Decreased TBW. -Increased Hct. -Reduced need for transfusions. -Increased osmotic pressure. -Increased cardiac output. -Increased arterial blood pressure. -Decreased PVR. -Better cerebral recovery from DHCA. -Decreased inflammatory mediators. |
| What are some arguments against MUF? | -Possible air embolism. -Circuit complexity and cost. -Prolonged exposure to foreign surface. -Patient can be concentrated before coming off bypass. |
| When would warm beating heart surgery be done on a peds patient? | -Pulmonary Stenosis & Shunts.-Certain cases which do not involve the left ventricle. -The patient is placed on CPB but heart is not stopped and patient is kept warm. |
| Glucose management in Peds. | Hypoglycemia may aggravate heart failure and must be avoided. |
| How is peds temperature management different than adults? | Due to the complex nature of congenital defects, peds patients are often brought to cooler temperatures than adults. b/c -reduction in metabolic rate and O2 consumption. -reduced excitatory neurotransmitter release |
| What does a nasopharyngeal temp probe measure? | Brain temp |
| What does the venous line temp measure? | core temperature when NO active warming/cooling is taking place. |
| What does esophageal temp measure? | Mediastinal structue can be affecterd by infusion temp |
| What does rectal temp measure? | muscle mass temp |
| What is Q10 | The increase or decrease in reaction rates or metabolic processes in relation to a teperature change of 10 degrees celsius. (if the Q10 is 2, than for an increase of 10 degrees the reaction rate will double.) |
| What is mild hypothermia for a ped patient? | 32-35 degrees celsius |
| What is moderate hypothermia for a peds patient? | 28-31 degrees celsius |
| What is deep hypothermia for a peds patient? | 18-28 degrees celsius |
| What is profound hypothermia? | Below 18 degrees celsius. |
| Explain pH stat in refernce to solubility and PP at cooler temps. | Decreasingthe temp of a solution decreases the kinetic energy, which decreases the tendency of the dissolved molecules to leave the solution (increased solubility) and decreases the relative pressure (decreases PP) |
| Describe the cross-over strategy in pH and alpha stat monitoring. | Use pH stat management during the first 10 minutes of cooling to promote cerebral cooling and metabolic suppression, followed by a change to alpha stat strategy to remove the acidosis and promote better enzymatic function upon cooling. |
| When is DHCA used? | -Aortic arch/descending aneurysms. -Vena cava repair. -congenital repairs (total anomalous pulmonary venous return & hypoplastic left heart syndrome) |
| What are some benefits for DHCA? | -Motionless field. -Cannula-free field. -Bloodless field. -Cerebral protection. |
| Temperature below what cause a cessation of the EEG? | Below 15 |
| What is the rewarming gradient for peds patients? | 8 degrees |
| Why should you avoid glucose solutions when perfusing peds patients? | -hyperglycemia tends to promote anaerobic glycolysis leading to formation of lactate and hydrogen ions. Hypothermia diminishes the effects of insulin on glucose. -This isreversed during rewarming |
| What is the desired flow rate and prefusion pressure for RCP? | flow rate = <500 mL/min. -Perfusion pressure = <25 mmHg |
Created by:
allievisner2
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