BACKGROUND: CO2 vasodilates and O2 vasoconstricts the cerebral vascular bed; the opposite is true in the lungs. When the brain and lungs are connected exclusively in series, which feedback loop predominates is unknown. The circulation of the superior cavopulmonary connection (SCPC) provides a unique physiology to answer this question. METHODS AND RESULTS: To determine cerebral and pulmonary blood flow and to establish the hierarchy of cerebral and pulmonary feedback mechanisms, 12 intubated, ventilated, single-ventricle patients in SCPC physiology (age 2.2+/-0.5 years) underwent magnetic resonance imaging velocity mapping of their jugular veins and aorta in room air, hypercarbia, and 100% O2. Flows in these vessels and arterial blood gases were measured. With 22+/-6 torr CO2 (Pco2) increased from 40 to 63 mm Hg, P<0.01), flow to the brain and lungs increased (1.5 to 2.7 L/min per m2, P=0.0003), Po2 improved (48 to 60 mm Hg, P=0.0004), and cardiac index increased (4.3 to 5.4 L/min per m2, P=0.0003). The increased cardiac index accounted for the increased cerebral and pulmonary blood flow (R=0.73, P=0.02) and cerebral O2 transport increased by 80% (P=0.0005) while preserving body O2 delivery. Hyperoxia did not change cerebral and pulmonary blood flow; Po2 increased 94% (P=0.01). CONCLUSIONS: The cerebral CO2 feedback loop predominates over the pulmonary one when they directly compete with each other. CO2 has a major impact on flow distribution whereas O2 has little impact. Increased CO2 improves cerebral oxygenation in SCPC patients. This may provide a clue in determining neurological sequelae in SC physiology and may influence timing of Fontan completion.
BACKGROUND: CO2 vasodilates and O2 vasoconstricts the cerebral vascular bed; the opposite is true in the lungs. When the brain and lungs are connected exclusively in series, which feedback loop predominates is unknown. The circulation of the superior cavopulmonary connection (SCPC) provides a unique physiology to answer this question. METHODS AND RESULTS: To determine cerebral and pulmonary blood flow and to establish the hierarchy of cerebral and pulmonary feedback mechanisms, 12 intubated, ventilated, single-ventricle patients in SCPC physiology (age 2.2+/-0.5 years) underwent magnetic resonance imaging velocity mapping of their jugular veins and aorta in room air, hypercarbia, and 100% O2. Flows in these vessels and arterial blood gases were measured. With 22+/-6 torr CO2 (Pco2) increased from 40 to 63 mm Hg, P<0.01), flow to the brain and lungs increased (1.5 to 2.7 L/min per m2, P=0.0003), Po2 improved (48 to 60 mm Hg, P=0.0004), and cardiac index increased (4.3 to 5.4 L/min per m2, P=0.0003). The increased cardiac index accounted for the increased cerebral and pulmonary blood flow (R=0.73, P=0.02) and cerebral O2 transport increased by 80% (P=0.0005) while preserving body O2 delivery. Hyperoxia did not change cerebral and pulmonary blood flow; Po2 increased 94% (P=0.01). CONCLUSIONS: The cerebral CO2 feedback loop predominates over the pulmonary one when they directly compete with each other. CO2 has a major impact on flow distribution whereas O2 has little impact. Increased CO2 improves cerebral oxygenation in SCPC patients. This may provide a clue in determining neurological sequelae in SC physiology and may influence timing of Fontan completion.
Authors: Erin M Buckley; Dalton Hance; Thomas Pawlowski; Jennifer Lynch; Felice B Wilson; Rickson C Mesquita; Turgut Durduran; Laura K Diaz; Mary E Putt; Daniel J Licht; Mark A Fogel; Arjun G Yodh Journal: J Biomed Opt Date: 2012-03 Impact factor: 3.170
Authors: W Gregory Hundley; David A Bluemke; J Paul Finn; Scott D Flamm; Mark A Fogel; Matthias G Friedrich; Vincent B Ho; Michael Jerosch-Herold; Christopher M Kramer; Warren J Manning; Manesh Patel; Gerald M Pohost; Arthur E Stillman; Richard D White; Pamela K Woodard Journal: Circulation Date: 2010-05-17 Impact factor: 29.690
Authors: W Gregory Hundley; David A Bluemke; J Paul Finn; Scott D Flamm; Mark A Fogel; Matthias G Friedrich; Vincent B Ho; Michael Jerosch-Herold; Christopher M Kramer; Warren J Manning; Manesh Patel; Gerald M Pohost; Arthur E Stillman; Richard D White; Pamela K Woodard Journal: J Am Coll Cardiol Date: 2010-06-08 Impact factor: 24.094
Authors: Monica E Kleinman; Allan R de Caen; Leon Chameides; Dianne L Atkins; Robert A Berg; Marc D Berg; Farhan Bhanji; Dominique Biarent; Robert Bingham; Ashraf H Coovadia; Mary Fran Hazinski; Robert W Hickey; Vinay M Nadkarni; Amelia G Reis; Antonio Rodriguez-Nunez; James Tibballs; Arno L Zaritsky; David Zideman Journal: Circulation Date: 2010-10-19 Impact factor: 29.690
Authors: Monica E Kleinman; Allan R de Caen; Leon Chameides; Dianne L Atkins; Robert A Berg; Marc D Berg; Farhan Bhanji; Dominique Biarent; Robert Bingham; Ashraf H Coovadia; Mary Fran Hazinski; Robert W Hickey; Vinay M Nadkarni; Amelia G Reis; Antonio Rodriguez-Nunez; James Tibballs; Arno L Zaritsky; David Zideman Journal: Pediatrics Date: 2010-10-18 Impact factor: 7.124
Authors: Mark D Rodefeld; Brandon Coats; Travis Fisher; Guruprasad A Giridharan; Jun Chen; John W Brown; Steven H Frankel Journal: J Thorac Cardiovasc Surg Date: 2010-06-18 Impact factor: 5.209
Authors: Liqun Sun; Christopher K Macgowan; John G Sled; Shi-Joon Yoo; Cedric Manlhiot; Prashob Porayette; Lars Grosse-Wortmann; Edgar Jaeggi; Brian W McCrindle; John Kingdom; Edward Hickey; Steven Miller; Mike Seed Journal: Circulation Date: 2015-03-11 Impact factor: 29.690