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
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