* Fluid resuscitation is mandatory in shock from traumatic haemorrhage * Massive use of resuscitative fluids following injury is now being disputed * Adequate resuscitation is no longer judged by presence of normal vital signs * Normalcy of organ and tissue specific mea­sured values are to be achieved * Search for a single endpoint that works for all trauma patients, is unrealistic * Resuscitate with appropriate fluid, in appropriate amount, at appropriate time

1. Endpoint of Resuscitation
Lt Col Md Rabiul Alam
MBBS, MCPS, FCPS
Classified Anaesthesiologist
Combined Military Hospital, Dhaka, Bangladesh

2. What is Endpoint?
• The final stage of a period
or process
• The point in a titration at
which a reaction is
complete, often marked
by a colour change

3. Learning Objectives
• Definition of Shock
• Compensated vs. uncompensated shock
• Importance of Resuscitation Endpoints
• Damage control resuscitation (DCR)
• Endpoints of Resuscitation
• Future Managements

4. Shock
• Shock is the imbalance between O2 delivery (DO2) and O2 consumption (VO2)
• ATLS Manual: An abnormality of the circulatory system that results in
inadequate organ perfusion and tissue oxygenation

5. Compensated vs. Uncompensated Shock
• Compensated & uncompensated shocks are to be understood to utilise the endpoints
• We are typically confronted with hypovolemic/hemorrhagic shock in trauma surgery
• ATLS manual classifies shock based on straightforward physiologic parameters,
including heart rate, blood pressure, mental status, and urine output
• However, their utility in the initial assessment of shock has been questioned and
these parameters alone are insufficient to define adequate resuscitation

6. Importance of Endpoints
• Shock is a spectrum of derangements
• It initiates with compensation to the uncompensated shock
• In compensated shock, CVS maintains perfusion adequate to normalise parameters
• Despite normalisation, ongoing tissue hypoxia may occur
• Leading to persistent acidosis and worsening the shock
• So, endpoints are to be improved as guides for appropriate resuscitation
• It prevents over-resuscitation, which is associated with increased mortality and ALI

7. Damage Control Resuscitation
• Truncating initial surgical procedures on severely injured victims
• To provide only interventions necessary to control haemorrhage
• To control initial severe sources and scopes of contamination
• Focused on re-establishing a survivable physiological status
• The victims will undergo continued advanced resuscitation
• Aggressive correction of coagulopathy, hypothermia & acidosis will be carried on
• Then, the patients will return to the OR for definitive repair/surgery

8. Damage Control Resuscitation (Cont…)

9. Damage Control Resuscitation (Cont…)
• Permissive hypotension (SBP=80)
• Use of blood products over
isotonic fluids for volume
replacement
• Rapid & Early correction of
coagulopathy with component
therapy

10. When resuscitation is completed?
• Initial Damage control resuscitation & the DC surgery
• Resuscitation is completed when…
• O2 debt is repaid
• Tissue acidosis is eliminated
• Aerobic metabolism is restored
• However, we define this with whatever monitors we use to determine the
endpoints

11. Resuscitation Endpoints
• The goals of resuscitation are:
• To normalize physiology through the restoration of DO2
• Most typically accomplished through volume loading to improve preload & CO
• Medications
• Optimisation of Hb
Numerous methods to guide resuscitation efforts in the treatment of shock, known
collectively as resuscitation endpoints

12. Hubs of the Endpoints
Resuscitation endpoints can be
divided into three groups –
• Haemodynamic
• Metabolic
• Regional perfusion

13. Haemodynamic Endpoints
• The balance between DO2 and oxygen consumption (VO2) dictates tissue oxygenation
• The Fick equation defines these physiologic parameters as a function of Hb conc,
cardiac function, arterial (SaO2), and venous (SvO2) oxygen concentrations:
• DO2 = CI x 1:34 x Hb x SaO2 (Efficient delivery = >600 mL/min/m2)
• VO2 = CI x 1:34 x Hb x (SaO2 - SvO2) [Good survivors = >170 mL/min/m2]
• Haemodynamic endpoints in resuscitation are based upon this understanding

14. Haemodynamic Endpoints (Cont…)
• MAP = DBP + 1/3 (SBP – DBP) = 65 mmHg
• CVP = 8 to 12 cmH2O in 1st 6 hours of resuscitation
• Pulmonary artery catheters, and Pulse contour wave analysis
• Mixed and Central venous oxygen saturation (>70%)
• Transthoracic Echocardiography (IVC calibre = > 20 mm)

15. Metabolic Endpoints
• Shock causes regional hypoxia because of impairment in DO2
• Anaerobic metabolism results in producing only two ATP molecules and pyruvate,
rather than the 36 ATP molecules that are produced under aerobic conditions
• Pyruvate is converted to lactic acid, causing worsening lactic acidosis as the shock
state and prolonged severe tissue hypoperfusion persists
• Based on this physiology, metabolic endpoints can be measured to assess global
tissue hypoxia and the systemic extent of shock

16. Metabolic Endpoints (Cont…)
• Lactate [<3.4]
• Arterial Base deficit [mild 2-5; moderate 6-14; severe >14 mmol/L]
• pH [<7.1]
• End-tidal CO2 [Survivors had higher ETCO2, lower arterial-ETCO2 differences,
and decreased alveolar dead space ratio compared to non-survivors
• New metabolic markers [Thrombospondin type 1, member 13 (ADAMTS13),
Heat shock protein 27 (HSP27), and Soluble P-selectin (sP-selectin)]

17. Regional Endpoints
• Gastric tonometry
• Gastric PCO 2 (PgmCO2 ) and intramucosal pH (pHi)
• Normal Gastric pHi is 7.4; pHi <7.32 is a good predictor of MODS and mortality
• Sublingual capnography [normal value of PSLCO2 is 45 mmHg]
• Near infrared spectroscopy (NIRS) [skeletal muscle oxyhaemoglobin levels]

18. Haemostatic resuscitation &
Haemorrhage control: a 4th Endpoint?
• Damage control resuscitation
• Damage control surgery
• Coagulation profile
• Thrombelastogram
• Thermal control
• Near infrared spectroscopy (NIRS) [skeletal muscle oxyhaemoglobin levels]

19. Thrombelastogram
• TEG - a real time evaluation of clotting by measuring the viscoelastic
properties of whole blood
• Resuscitation guide in hemorrhagic shock, trauma, transplant, & CVTS.
• DCR with early administration of blood products in a balanced ratio and
prevention and correction of coagulopathy improve outcomes
• TEG can be effectively used to guide these interventions, hemostasis should
be considered an endpoint in resuscitation

20. Future Management
• Administration of agents which regulate cellular function
• Manipulation of shock-related pathophysiological alterations such as:
• Complement and granulocyte activation
• Endothelial activation & leukostasis
• Edema formation with resultant organ injury
• Use of oxygen carriers (fluorocarbons and modified Hb), antioxidants, NO scavengers
and anti-endotoxin compounds

21. Summary
Haemodynamic:
MAP
CVP, PAC, Pulse contour analysis
SvO2, ScvO2
TTE
Metabolic:
Lactate
Base deficit, pH
ETCO2
New makers
Regional:
Gastric tonometry
Sublingual capnography
NIRS
Haemostatic & Haemorrhagic:
Early Blood product in a balanced ratio
Minimization of crystalloids
Coagulation profile, Thrombelastogram
Resuscitation
Endpoints

22. Conclusion
• Fluid resuscitation is mandatory in shock from traumatic haemorrhage
• Massive use of resuscitative fluids following injury is now being disputed
• Adequate resuscitation is no longer judged by presence of normal vital signs
• Normalcy of organ and tissue specific measured values are to be achieved
• Search for a single endpoint that works for all trauma patients, is unrealistic
• Resuscitate with appropriate fluid, in appropriate amount, at appropriate time

23. References
1. Connelly CR, Schreiber MA. Endpoints in resuscitation. Curr Opin Crit Care
2015;21:512-9.
2. Tisherman SA, Barie P, Bokhari F, Bonadies J, Daley B, Diebel L, et al.
Resuscitation Endpoints. J Trauma 2004;57:898-912.
3. Ganapathy N. End points in trauma management. Indian J Anaesth
2007;51:479-85.