Transcript Monitoring Intraoperative Blood Lactate Levels

Monitoring Intraoperative Blood Lactate Levels:
Implications for Cardiopulmonary Bypass
Maggie Savelberg B.Sc.(H), Perfusionist Fellow
London Health Sciences, London, Ontario
Outline:
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Objective: Marker for Adequate Perfusion
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Solution: Lactic Acidosis
Study: Patient Selection/Methods
Study: Results/Conclusion
Objective: Appropriate Marker for Adequate Perfusion
Cardiopulmonary
Bypass
Function
Solution
Challenge
Allow adequate
systemic
oxygenation
and perfusion
during cardiac
surgical
procedure.
Periods of
acute tissue
hypoperfusion:
- Poor venous return
- Low volumes/flows
- Patient anatomy
- Surgical technique
- Circulatory arrest
- Hemodilution
Monitoring of
intraoperative
lactate levels &
acid/base status
leading to
therapeutic
intervention to
improve postoperative course.
Solution: Clinical Definitions & Significance?
Lactic
Lactic Acidosis
Acidosis
vs
Lab Abnormalities
↑ Lactate > 2.0mmol/L
↓ HCO3- / BE
Metabolic
↓ Arterial pH
Acidosis
↑ Anion gap
-Difficult to identify
- Lactic acidosis better
correlated with
in-hospital mortality
Demers et al., Ann of Thorac Surg 2000;70:2082-2086
Lee et al., Emerg Med J 2008;25:659-665
Hyperlactatemia
Lab Abnormalities
↑ Lactate >2.0 mmol/L
Mild
pH ≥ 7.35
La- 2.0-5.0
Severe
pH ≥ 7.35
La- > 5.0
-Easily identified
-Chart & Monitor
-Substitute marker
Study: Patient Selection & Methods
1,376 patients
- Exclusions
72% ♂
79%
CABG
Sex
28 % ♀
1,259
patients
Surgery
17%
Valve
82%
18%
Lactate <4.0mmol/L
Lactate >4.0mmol/L
Identification ?
Lactic Acidosis resulting
↓ pH - upregulation
anaerobic
metabolism
↓ vascular removal
Normal Range
pH normal
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2
3
- protonated transporters fail ↑ La/H+
- morbidity & mortality ↑
- 11% mortality rate vs 1.4%
when lactates rise over 4 mmol/L3
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Lactate (mmol/L)
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10
Correction Zone
It is here – intraoperatively where patient outcome can be improved
by determining the cause and correcting hypoperfused states.
3Demers
et al., Ann of Thorac Surg 2000;70:2082-2086
Prevention & Treatment of Lactic Acidosis
Cause
Tissue
Hypoxia
↑ Tissue
Oxygenation
↑ Flow rate
↑ Mechanical
Ventilation
↑FiO2
↑Hgb
CHEST 2000; 117:260-267
↓ Oxygen
Demand
↑ Sedation
Hypothermia
↑ Blood pH
NaHCO3
Summary: Intercollaborative Team Effort
Surgeon
Perfusion
Anesthesia
- Communicate
our difficulties
- Changes
-Understanding
- Willingness to
accommodate
Taken From: Google Imagies at http://images.google.ca