lactate and base deficit in trauma
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Lactate and Base Deficit in Trauma
January 19, 2007
James HuffmanEmergency Medicine, PGY-1
Outline
1. Case
2. Lactate Physiology Clinical utility in trauma patients
3. Base Deficit Physiology Clinical utility in trauma patients
4. Summary
Case: Claresholm, Alberta
28M: MVC >130km/h, restrained, no airbag, EtOH, >30cm passenger space intrusion, BP 88/50 on scene
Heathy otherwise, no meds, NKDA
Vitals: T: 36.2 C HR: 104 RR: 24 BP: 102/68 O2: 98% on 15L nrb
Case: A – Patent. Able to vocalize B – Bilateral breath sounds C – Vitals as above. All pulses palpable, CRT 2sec. D – Moving all four limbs. No signs of head injury. E – Seat belt sign present. Abdo moderately tender.
Pelvis stable. No obvious fractures/open wounds F – 2 IV’s running wide, Foley in.
Brand new U/S, but not avail (being used by other ED doc for a gyne scan)
Question:
How can you tell who is “sick”?
How do you know if we’re making them better?
Resuscitation end points:
Shock:“An abnormality of the circulatory system that results in
inadequate organ perfusion and tissue oxygenation” (ATLS)
Inadequate perfusion inadequate O2 delivery
anaerobic metabolism acidosis
Therefore, resuscitation is complete when O2 debt is repaid, acidosis is eliminated and aerobic metabolism restored.
Porter et al. J of Trauma; 44 (1998).
Lactic Acid History: sour milk
Pathophysiology
Type A Type B
Decreased O2 delivery Shock (hypovolemia)
Severe Anemia Hypoxemia CO poisoning Increased O2 demands
Inadequate O2 utilization SIRS DM Malignancy Metabolic Infections Drugs/toxins
Other D-Lactic Acidosis
Lactate Pitfalls Anion Gap
Low albumin lowers the AG
Ethanol
Other Drugs/Toxins Metformin Propofol Beta-2 agonists Salicylates Etc.
Inborn errors of metabolism, G6PD deficiency
Sampling location
Clinically…
Useful in guiding resuscitation
Elevated levels are predictive of mortality
Time to normalize levels also strongly predictive
Time to clear lactate <24h 25-48h >48h Did not clear
Mortality 10% 20% 23% 67%
Husain et al. American J of Surgery 185 (2003) 485-491
Predicting Mortality
Base Deficit The amount of strong base that would have to
be added to 1L of blood to normalize the pH
Calculated from pH, PaCO2 and HCO3
-
Usually more positive than -2mEq/L
NOT simply an indirect measure of lactate Elevated in other acidemic states (DKA, ASA tox,
CRD)
Base Deficit
In hemorrhage, this value becomes more negative before we see changes to pH and BP
In pure hemorrhagic and septic shock, BD directly correlates with lactate levels
Severely abnormal BD (≤ 10) in trauma patients is assoc. with significantly higher mortality, rates of ARDS and MOF Davis et al. J of Trauma; 44 (1998)
Base Deficit
Largest clinical series conducted by Rutherford in 1992 Retrospective review of 3,791 trauma patients
BD of -15 in patients <55 years without HI had significantly increased mortality
If age>55 or HI present, BD of -8 showed significantly increased mortality
Which is better?
Take Home Points
Lactate: Normalized serum lactate appears to be a
suitable end point for resuscitation
High initial lactate and moreover, time to normalize this value are predictive of mortality risk
Take Home Points
Base Deficit: A large negative BD (<-2mEq/L) may represent
early hemorrhage/hypovolemic shock
Very high initial BD (>10-15) in trauma patients represents a significant mortality risk
Resuscitation:
Correction of serum lactate and BD are reasonable markers of resuscitation
References:Adams, B., Bonzani, T. and C. Hunter. 2006. The anion gap does not accurately screen for lactic
acidosis in emergency department patients. Emerg Med J. 23; 179-82.
Davis J., et al. 1998. Base Deficit is Superior to pH in Evaluating Clearance of Lactic Acidosis after Traumatic shock. J of Trauma. 44; 114-17.
Fall, P. and H. Szerlip. 2005. Lactic Acidosis: From sour milk to septic shock. J. of Intensive Care Medicine. 20(5); 255-71.
Husain, F., et al. 2003. Serum lactate and base deficit as predictors of mortailty and morbidity. American J of Surgery. 185; 485-91.
Jones, A. and J. Kline. 2006. Shock. In Rosen’s Emergency Medicine. Concepts and Clinical Practice (6th Edition). Philadelphia, PA: Mosby Elsevier.
Nguyen, B., et al. 2006. Severe Sepsis and Septic Shock: Review of the literature and emergency department management guidelines. Ann of Emergency Medicine. 48(1); 28-54.
Porter, J., and R. Ivatury. 1998. In Search of Optimal End Points of Resuscitation in Trauma Patients: A Review. J of Trauma. 44; 908-13.
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