Impact of inspired gas mixtures on preoperative infants with hypoplastic left heart syndrome during controlled ventilation

Circulation. 2001 Sep 18;104(12 Suppl 1):I159-64. doi: 10.1161/hc37t1.094818.


Background: Management strategies for preoperative infants with hypoplastic left heart syndrome (HLHS) include increased inspired nitrogen (hypoxia) and increased inspired carbon dioxide (hypercarbia). There are no studies directly comparing these 2 therapies in humans. This study compares the impact of hypoxia versus hypercarbia on oxygen delivery, under conditions of fixed minute ventilation.

Methods and results: Ten anesthetized and paralyzed preoperative infants with HLHS were evaluated in a prospective, randomized, crossover trial comparing hypoxia (17% FIO(2)) with hypercarbia (2.7% FICO(2)). Each patient was treated in a random order (10 minutes per condition) with a recovery period (15 to 20 minutes) in room air. Arterial (SaO(2)) and superior vena caval (SvO(2)) co-oximetry and cerebral oxygen saturation (ScO(2)) measurements were made at the end of each condition and recovery period. ScO(2) was measured by near infrared spectroscopy. Hypoxia significantly decreased both SaO(2) (-5.2+/-1.1%, P=0.0014) and SvO(2) (-5.6+/-1.7%, P=0.009) compared with baseline, but arteriovenous oxygen saturation (AVO(2)) difference (SaO(2)-SvO(2)) and ScO(2) remained unchanged. Hypercarbia decreased SaO(2) (-2.6+/-0.6%, P=0.002) compared with baseline but increased both ScO(2) (9.6+/-1.8%, P=0.0001) and SvO(2) (6+/-2.2%, P=0.022) and narrowed the AVO(2) difference (-8.5+/-2.3%, P=0.005). Both hypoxia and hypercarbia decreased the balance between pulmonary and systemic blood flow (Qp:Qs) compared with baseline.

Conclusions: In preoperative infants with HLHS, under conditions of anesthesia and paralysis, although Qp:Qs falls in both conditions, oxygen delivery is unchanged during hypoxia and increased during hypercarbia. These data cannot differentiate cerebral from systemic oxygen delivery.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Administration, Inhalation
  • Anesthesia
  • Arteries / physiopathology
  • Blood Gas Monitoring, Transcutaneous / instrumentation
  • Brain / metabolism
  • Carbon Dioxide / administration & dosage*
  • Cross-Over Studies
  • Hemodynamics / drug effects
  • Humans
  • Hypoplastic Left Heart Syndrome / physiopathology
  • Hypoplastic Left Heart Syndrome / therapy*
  • Hypoxia / blood
  • Hypoxia / chemically induced
  • Infant, Newborn
  • Monitoring, Physiologic
  • Nitrogen / administration & dosage*
  • Oxygen / administration & dosage*
  • Oxygen / analysis
  • Oxygen / metabolism
  • Preoperative Care*
  • Prospective Studies
  • Respiration, Artificial / methods*
  • Spectroscopy, Near-Infrared


  • Carbon Dioxide
  • nitrox
  • Nitrogen
  • Oxygen