Patients at risk for low systemic oxygen delivery after the Norwood procedure

Accurate Measurement of Systemic Oxygen Consumption in Ventilated Children with Congenital Heart Disease

“…Previous studies used assumptions for VO 2 of 160 or 180 mL/min/m 2 to calculate hemodynamics (Charpie, Dekeon et al 2001;Hoffman, Ghanayem et al 2000;Maher, Pizarro et al 2003;Tweddell, Hoffman et al 1999). Those values are much higher than the directly measured VO 2 in our patients, which ranged from 45 to 152 mL/min/m 2 ( Figure 8).…”

“…Our adaptation of the respiratory mass spectrometer to pediatric ventilators has allowed us to extensively study systemic hemodynamics and oxygen transport, and the factors affecting them, before and after cardiac www.intechopen.com Accurate Measurement of Systemic Oxygen Consumption in Ventilated Children with Congenital Heart Disease 303 surgery in children with congenital heart defects (Li, Hoschtitzky et al 2004;Li, Hoskote et al 2005;Li, Schulze-Neick et al 2000;). The importance of oxygen transport is increasingly appreciated in the care of critically ill patients, particularly after CPB (Gilbert, Haupt et al 1986;Haupt, Gilbert et al 1985;Hoffman, Ghanayem et al 2000;Li, Hoschtitzky et al 2004;Li, Hoskote et al 2005;Li, Schulze-Neick et al 2000;Oudemans-van Straaten, Jansen et al 1996;Powers, Mannal et al 1973;Tweddell, Hoffman et al 1999;). The fundamental requirement of ICU management is to match systemic oxygen delivery (DO 2 ) to VO 2 , to sustain cellular metabolism and end-organ function.…”

“…In previous studies in humans, arterial superior vena caval oxygen saturations, and their derivations were most commonly used as surrogates of DO 2 (Charpie, Dekeon et al 2001;Hoffman, Ghanayem et al 2000;Maher, Pizarro et al 2003;Tweddell, Hoffman et al 1999). In some human studies, derived values of pulmonary and systemic blood flows have been obtained, but are based on the key assumption of a fixed VO 2 of 160 or 180 mL/min/m 2 (Charpie, Dekeon et al 2001;Hoffman, Ghanayem et al 2000;Maher, Pizarro et al 2003;Tweddell, Hoffman et al 1999). However, as demonstrated above in section 2.1.1 (Figure 2), postoperative VO 2 has wide inter-and intra-patient variability in children (Li, Schulze-Neick et al 2000;.…”

Hemodynamic Profile After the Norwood Procedure With Right Ventricle to Pulmonary Artery Conduit

“…A commonly used management strategy for these patients has been the limitation of pulmonary blood flow by manipulation of pulmonary or systemic vascular resistance. Techniques have included the addition of carbon dioxide to the inspired gas mixture, 7,8 use of hypoxic gas, 9,10 controlled hypoventilation, 11 pharmacological manipulation of systemic vascular resistance, 12,13 and manipulation of shunt size. 14 The RV-PA conduit modification created a hemodynamic profile characterized by a higher aortic diastolic pressure, a decreased Qp:Qs, a narrowed systemic pulse pressure, and a higher coronary perfusion pressure.…”

Rebuttal by Ebenroth

“…Some of Dr. Ebenroth's references pertain to the postoperative single ventricle heart, in which Qp is limited by a restrictive shunt (3,8). We do not feel those studies apply to this discussion.…”