Faculty Collaboration Database

Venous saturation and the anaerobic threshold in neonates after the Norwood procedure for hypoplastic left heart syndrome. Ann Thorac Surg 2000 Nov;70(5):1515-20; discussion 1521

Date

11/28/2000

Pubmed ID

11093480

DOI

10.1016/s0003-4975(00)01772-0

Scopus ID

2-s2.0-0033766692 (requires institutional sign-in at Scopus site)   151 Citations

Abstract

BACKGROUND: Reduction in oxygen delivery can lead to organ dysfunction and death by cellular hypoxia, detectable by progressive (mixed) venous oxyhemoglobin desaturation until extraction is limited at the anaerobic threshold. We sought to determine the critical level of venous oxygen saturation to maintain aerobic metabolism in neonates after the Norwood procedure (NP) for the hypoplastic left heart syndrome (HLHS).

METHODS: A prospective perioperative database was maintained for demographic, hemodynamic, and laboratory data. Invasive arterial and atrial pressures, arterial saturation, oximetric superior vena cava (SVC) saturation, and end-tidal CO2 were continuously recorded and logged hourly for the first 48 postoperative hours. Arterial and venous blood gases and cooximetry were obtained at clinically appropriate intervals. SVC saturation was used as an approximation of mixed venous saturation (SvO2). A standard base excess (BE) less than -4 mEq/L (BElo), or a change exceeding -2 mEq/L/h (deltaBElo), were used as indicators of anaerobic metabolism. The relationship between SvO2 and BE was tested by analysis of variance and covariance for repeated measures; the binomial risk of BElo or deltaBElo at SvO2 strata was tested by the likelihood ratio test and logistic regression, with cutoff at p < 0.05.

RESULTS: Complete data were available in 48 of 51 consecutive patients undergoing NP yielding 2,074 valid separate determinations. BE was strongly related to SvO2 (model R2 = 0.40, p < 0.0001) with minimal change after adjustment for physiologic covariates. The risk of anaerobic metabolism was 4.8% overall, but rose to 29% when SvO2 was 30% or below (p < 0.0001). Survival was 100% at 1 week and 94% at hospital discharge.

CONCLUSIONS: Analysis of acid-base changes revealed an apparent anaerobic threshold when SvO2 fell below 30%. Clinical management to maintain SvO2 above this threshold yielded low mortality.

Author List

Hoffman GM, Ghanayem NS, Kampine JM, Berger S, Mussatto KA, Litwin SB, Tweddell JS

Authors

George M. Hoffman MD Chief, Professor in the Anesthesiology department at Medical College of Wisconsin
Kathleen Mussatto Ph.D. Associate Professor in the School of Nursing department at Milwaukee School of Engineering

MESH terms used to index this publication - Major topics in bold

Anaerobic Threshold
Cardiac Surgical Procedures
Hemodynamics
Humans
Hypoplastic Left Heart Syndrome
Infant, Newborn
Monitoring, Physiologic
Oximetry
Oxygen
Postoperative Period
Prospective Studies
Vena Cava, Superior