CHSU AND PICU Staff Meeting Greg Merritt, BSRC, RRT-NPS Pediatric Clinical Educator

December 2012 - Objectives ECMO CPT Oxygen (flow verses fio2)

ECMO extracorporeal membrane oxygenation prolonged mechanical cardiac and pulmonary support In simple terms, venous blood is removed from the patient, passed through an artificial membrane to remove CO2, add O2 and the blood is then returned to the patient.

History of Cardiopulmonary Support 1952: first successful ASD closure development of cardiopulmonary bypass 1935-1954 goals: support circulation oxygenation/ventilation bloodless surgical field ECMO as a technology was unavailable until after the development of hemodialysis and cardiopulmonary bypass. Research for cardiac and pulmonary support began before the turn of the century but became very aggressive in the 1930s. By 1950, research began in humans. Several obstacles needed to be overcome for successful bypass. This included a method to oxygenate/ventilate the blood and a method to support the circulation while providing a bloodless surgical field for the surgeon to work.

History of Cardiopulmonary Support low flow bypass cross circulation slow intraoperative transfusion of hyperoxygenated blood Methods to provide adequate oxygenation included: low blood flow rates (about 10cc/kg/min via occlusion of the vena cava, sparing of the azygous system, this allowed adequate oxygenation for about 30 minutes), cross-circulation, utilization of animal lungs, slow intraoperative transfusion of hyperoxygenated blood (donor had arm inserted into warm water bath during donation to hyperoxygenate the blood), and finally utilization of artificial lung/oxygenator.

Cross-Circulation Successful surgical management of 45 patients. No donor mortality or morbidity. ASD, PDA, VSD, tetralogy of Fallot, pulmonary stenosis, anomalous pulmonary venous return. 28 of 45 patients survived (62%).

History of Cardiopulmonary Support film oxygenator membrane oxygenator bubble oxygenator Lillehei was one of the first to use a prosthetic heart/lung machine for cardiac surgery, thereby opening the door to routine and successful use of extracorporeal circulation for cardiac bypass. But as experience with this technique developed during the 1950s, it became obvious that this life-sustaining technique became lethal when used for more than a few hours. Thrombocytopenia, coagulopathy, hemolysis, generalized edema and deterioration of organ function all occurred in proportion to the amount of time spent on bypass. Film oxygenators spread anti-coagulated blood thinly over a surface and then exposed the blood to oxygen. This method was difficult to utilize because the equipment was very cumbersome. It was realized that the toxicity seen with bypass was a result of direct exposure of blood to oxygen. In bubble oxygenators, oxygen was bubbled through the blood as it went through the oxygenator. These oxygenators were easy to assemble and were disposable but has the added difficult of oxygen bubble removal prior to reinfusion to prevent air embolization.

ECMO silicone rubber membrane oxygenator first successful ECMO 1972 first successful neonatal ECMO 1976 Membrane oxygenator then developed. The blood and gas paths are physically separated by a semi-permeable membrane which allows oxygen diffusion to the RBCs. This method allowed for large blood volume movement without the risk of air embolism or excessive hemolysis. Initially this method was very cumbersome because very large surface areas were required for the gas exchange. But the development of a new material called silicone rubber allowed the production of small but efficient oxygenators. These oxygenators allow for prolonged bypass without excessive blood trauma, acidosis or multi-organ failure. 1972: first successful ECMO case: young man with multi-trauma including ruptured aorta. Supported on ECMO for several days. 1976: first successful neonatal case. PPHN 1975-1982: Phase I safety and efficacy. 50 infants with predicted mortality of 100%, 66% survival Bartlett 1985. Play the winner, prospective randomized trial. 12 pts met ECMO criteria, 1 child randomized to conventional therapy - died. Remaining patients reassigned to VA ECMO - all survived.

ECMO Goals support cardiac and respiratory systems until disease process resolves avoid chronic lung injury from volutrauma ECMO goals are simple in concept: to provide cardiac/pulmonary support until a reversible disease process resolves. An important goal of ECMO to to prevent chronic lung disease from ventilator induced volutrauma. This is important to remember as we can often maintain a patient with medical management but the cost may be severe chronic lung disease.

ECMO Precautions NO Suctioning Past ETT NO Deep Nasal/Oral Suctioning NO Cuff Blood Pressure Checks NO Needle Sticks NO Rectal Temperatures NO Line Removals

Respiratory Lung rest for pulmonary failure Prevention of total lung collapse Gentle pulmonary toilet Increase vent settings when pulmonary compliance improves and ECMO is weaned

Selection Criteria failure of maximal medical management reversible cardiac or pulmonary disease GA > 34 weeks birth weight >2 kg no major malformations no coagulopathy or severe hemorrhage

Qualifying Criteria AaDO2 > 600 torr PaO2 < 50 mmHg OI > 40 acute deterioration problems with criteria Goals are to determine criteria that predict a high probability of death. Alveolar-arterial gradient = atomospheric pressure - 47 - (PaCO2 + PaO2)/FiO2, >600 torr for over 12 hours PaO2 < 50 mmHg for > 4 hours OI = PAW X FiO2 X 100/PaO2 20-40 has 50-80% mortality >40 = 80-90% mortality

Reversible Disease PPHN meconium aspiration pneumonia/sepsis congenital diaphragmatic hernia respiratory distress cardiac support Survival PPHN: 79% (CMC 62%) mec aspiration 94% (CMC 89%) pneumonia 53% (we had 0 pts) sepsis 76% (100%) respiratory distress 84% (25%) CDH 54% (44%) Overall neonatal runs are down. Peak was 1992 with 1500 runs. 1999 had 500 runs.

CPT Devices There has been a lot of discussion about which device to use for CPT. Specifically – “What is the largest patient that the Neocussor can be used on? I looked through the data as well as call the technical support. I had a tough time getting specifics from the company. The company said it is based off the size of the chest. I expressed that they should not use the Neocussor on patients larger than 1800g. I also expressed that hand CPT are better than percussor or vibes

Oxygen Therapy We discussed the use of high flow oxygen therapy and how much oxygen is actually delivered to the patient. We also discussed “meeting inspiratory demand?Lastly we discussed how HFNC can mask the patients true respiratory status.

Questions?? 1. How effective is aerosol delivery due to a large amount of rainout.