Severe Sepsis and Septic Shock:Lactic Acid and ScvO2

Klorissa Kavan, Arman Pirzad, and Steven Simpson, MD

University of Kansas Medical Center

Hypothesis

We hypothesize that in patients with severe sepsis and/or septic shock, levels of blood lactate and central venous oxygen saturation percentages are inversely correlated.

What is Sepsis? Infection SIRS

– Systemic Inflammatory Response Syndrome Fever or Hypothermia (>101º F or <96.8º F) Tachycardia (>90 bpm) Tachypnea (>20 rpm) Leukocytosis or Leukopenia

– WBC Count >4 or <12 – 10% Neutrophil Immaturity

Sepsis– Infection + ≥2 SIRS Criteria

Severe Sepsis– Sepsis + Organ Dysfunction

Septic Shock– Severe sepsis that persists despite fluid resuscitation

Increasing likelihood of mortality

Lactic Acid Organic Compound that plays a role in many biochemical processes Formation

– A molecule formed when the body breaks down Glucose in order to produce usable energy

– Product of anaerobic metabolism– Doesn’t produce nearly as much ATP

2 molecules, rather than 36 in aerobic respiration– Predictor of mortality

No Oxygen OxygenNo Oxygen

Aerobic vs. Anaerobic Metabolism

Oxygen

No Oxygen

Central Venous Oxygen Saturation (ScvO2) Reflects the relationship between oxygen consumption and

oxygen delivery to the bodily tissues Read through a catheter placed in the superior vena cava, which

brings deoxygenated blood back to the right atrium of the heart Tissue Oxygenation is dependent on:

– Tissue Perfusion– DO2 = Cardiac Output x CaO2

Cardiac Output × (Hemoglobin × 1.34 × % Sat) × 10– Metabolic demand of cells– Etc.

Normal: ~70% or 0.7

So how are ScvO2 and lactate levels related?

Anything below a normal 70% ScvO2 level indicates:– Potential tissue hypoxia– Anaerobic metabolism

There is very limited research connecting the two.

Hypothesis

We hypothesize that in patients with severe sepsis and/or septic shock, levels of blood lactate and central venous oxygen saturation percentages are inversely correlated.

ScvO2 declines with decreased O2

decreased O2 delivery results in increased lactate production

HERON

The Healthcare Enterprise Repository for Ontological Narration

Integration method for clinical and biomedical data for translational research

Iteration of the i2b2 research database Provides complete clinical data on all patients admitted

to the University of Kansas Hospital Allows development of queries to refine a list of

patients that meet a researcher’s criteria

SPSS

Statistical Package for the Social Sciences IBM software package designed for statistical analyses

– Designed to handle data sets much larger than could be run using Microsoft Excel

Common researching tool to determine statistical relationships

Preliminary Findings

638 patients; 2558 data pairs563 survivors; 2460 data pairs75 non-survivors; 98 data pairs

Modifications to the Original Study

Removal of peripheral venous gases from the data set Redefining our time constraints

– One hour for all measurements read, rather than two Just shy of 1300 patients matched our researching

criteria

My Role May 26, 2015-August 14, 2015 Reading and learning to comprehend

medical research studies Daily meetings with Dr. Simpson and

shadowing him in the ICU Meetings with the KUMC Data

submission team Designing Clinical Research Designing HERON queries SPSS to statistically analyze our data Helping to write the Abstract

Where Are We Now?

Recently submitted our final data submission and received the filtered data back from the KUMC medical informatics team

Currently running SPSS analyses on data to determine relationships between lactate levels and ScvO2

Although my fellowship is now over, I still am planning to work with Dr. Simpson until the completion of our research paper, which we will then submit to medical journals.

Acknowledgements

•Parker B. Francis Foundation Board of Directors

•Dr. Steven Simpson

•Dr. Navneet Dhillon

•Christina Hopkins

•Dr. Thomas Martin

•Deborah Snapp