Risk adapted peri operative haemodynamic management Clinical relevance of perioperative ScvO 2 monitoring Euroanaesthesia 2007 Meeting Munich, Germany, 9.-12. June 2007 Claus-Georg KRENN Dept. of Anaesthesia and General Intensive Care, University Vienna claus.krenn@meduniwien.ac.at
standard hemodynamic monitoring 31 of 36 medical shock patients: resuscitated to normal MAP and CVP have global tissue hypoxia (Scv02 < 70% ) and lactate >2 mmol/l Rady, AJEM 1994
Standard hemodynamic monitoring might be not enough to assess tissue oxygenation in patients at risk!!! 180 150 MAP [mmhg] 120 90 60 Rady, AJEM 1994 30 n= 1232 100 300 500 700 900 1100 DO 2 ml*m -2 *min -1
Für die Entwicklung der Lehre vom Kreislauf war es gewiss ein Verhängnis, dass das Stromvolumen verhältnismäßig so umständlich, der Blutdruck aber gar so leicht bestimmbar ist - deshalb gewann das Blutdruckmanometer einen geradezu faszinierenden Einfluss, obwohl die meisten Organe gar nicht Druck, sondern Stromvolumen brauchen. A. Jarisch Kreislauffragen ; 1928
The conventionally measured variables such as blood pressure, heart rate and urine output were of little prognostic value. Only variables related to volume and flow (blood volume, cardiac output, oxygen delivery and consumption) had a significant prognostic value. W. C. Shoemaker 1979
Macrohemodynamics regional blood flow
Macrohemodynamics regional blood flow
Macrohemodynamics regional blood flow need for a relieable clinically applicable and useful indicator of adequate tissue oxygenation
Macrohemodynamics regional blood flow need for a relieable clinically applicable and useful indicator of adequate tissue oxygenation monitoring should be dynamic - interventions immediately affect parameter
physiologic key question of oxygen transport adequacy or mismatch
the controversy of increasing O 2 transport 10 5 0-5 0 2 4 6 8 10 12 16 20 24-10 -15-20 -25-30 goal directed therapy GDT increase O 2 delivery to (supra)normal values!!! WC Shoemaker et al. 1973, Arch Surg 106
the controversy of increasing O 2 transport Hayes et al., N Engl J Med 1994
ScvO 2 VO 2 DO 2 DO 2 VO 2 Stress PaO 2 PaO 2 Anesthesia Pain Hb Hb Hypothermia Shivering CO CO Fever Hypovolemia
Oxygen delivery (DO 2 ) 1) not necessarily increases oxygen consumption 2) why not measure oxygen consumption? 3) use mixed venous oxygen satturation as marker of oxygen consumption SvO 2
Meta analysis of hemodynamic optimization
Meta analysis of hemodynamic optimization
from SvO 2 to mixed central venous O 2 satturation. ScvO2 SvO 2
from SvO 2 to mixed central venous O 2 satturation. ScvO2 SvO 2 V. cava sup. - before the right heart
early goal directed therapy E. Rivers et al.; N Engl J Med 2001
early goal directed therapy
early goal directed therapy E. Rivers et al.; N Engl J Med 2001
ScvO 2 - continuous measurments continuous fiberoptic venous oxymetry
ScvO 2 - continuous measurments
is ScvO 2 a valuable parameter for monitoring? in all patients? in all clinical situations? without endangering by itself? with impact on prognosis?
ScvO 2 in critically ill patients 61 patients, paired measurment on admission correlation coefficient 0.945 both parameters are closely related and interchangeable for the first evaluation Ladakis et al. Respiration 2001:68
ScvO 2 in critically ill patients continuously measured in high-risk patients, paired measurment Reinhart et al. ICM 2004: 30
ScvO 2 was unaffected by changes in physiologic variables (ph, temp., a.s.o.) averaged 7 ± 4 % higher paralleled SvO 2 in more than 90% correlation coeff. r = 0.96
ScvO 2 in septic shock patients 16 patients, paired measurments over 24 h Varpula et al., ICM 2006; 32:1336
ScvO 2 difference between SvO 2 and ScvO 2 varies considerably over time ScvO 2 being higher at all TP ScvO 2 inadequate tool to estimate the flow-weighted oxygen balance of the whole body (SvO 2 ) but accurately reflects hypovolemia
ScvO 2 in critically ill patients 53 patients, surgical and medical calculating VO 2 on basis of ScvO 2 produced unaccaptable large errors difference might be attributed to mixing with coronary sinus blood Chawla et al., CHEST 2004:126
ScvO 2 in perioperative patients at risk Morbidity Increased length of hospital stay Mortality
high risk patients Emergency abdominal aortic surgery Trauma, such as fractured neck of femur Neurological Cardiovascular severe valvular heart disease aortic dissection Gastrointestinal Colon resection large and small bowel obstruction Pancreatic surgery
Reason for being high risk Co-morbidity elderly patients with significant medical problems Type of surgery often long procedure with significant blood loss fluid shift, electrolyte and nutritional problems and possibility of post-op pain (effects breathing) abdominal surgery is associated with physiological stress response Emergency or elective Patients who present with urgent emergency cases have worse outcomes
ScvO 2 fluctuations occur in the post-op period not only associated with DO 2 but also related to oxygen consumption ScvO 2 changes are independently associated with postoperative complications ScvO 2 lowest value (cut off 64 %) was significantly lower in patients who developed complications
absolute values differed unaccaptable r = 0.76 however the trend was clinically acceptable as substitute of SvO 2
ScvO 2 in cardiac surgical patients 60 patients, 5 TP, 300 paired measurments Sander et al. ICM 2007
ScvO 2 weak correlation over all measurments more pronounced association in values below 70% attributed to increase of oxygen extraction rate of splanchnic circulation in the course of ACBP crafting ScvO 2 might overestimate SvO 2 thus only high values can exclude tissue hypoxia
Goal directed therapy setting, aiming at adequate DO 2 by improving CO (stroke volume optimization) by fluid and catecholamine administration resulted in reduced mortality and HLoS
ScvO 2 reflects the degree of oxygen extraction from the upper part of the body including the brain values are slightly higher than SvO 2 difference to SvO 2 might vary with cardiovascular insufficiency thus in case of low SvO 2 it should not be used alone but in combination with other markers
Nguyen et al., Crit Care Med 2007, 35
practical aproach? perfusion deficit? advanced monitoring global or regional problem? S cv O 2? EGDT
Conclusion ScvO 2 - monitoring identify high risk patients and implement ScvO 2 monitoring early - as easy as with insertion of the central venous catheter
Conclusion ScvO 2 - monitoring implement early in high risk patients check signs of reduced tissue perfusion s.a.: complete hemodynamic evaluation (CO, stroke volume ~ variation, GEDV, lactate, PDR of ICG, diuresis)
Conclusion ScvO 2 - monitoring implement early in high risk patients check signs of reduced tissue perfusion rely on the course targeting your hemodynamic goals which in almost all cases mirrors the course of SvO 2
Conclusion ScvO 2 - monitoring implement early in high risk patients check signs of reduced tissue perfusion rely on the course treat according to a standardized algorythm aiming at adequate (regional) perfusion
focus on : early and goal directed
Gemischtvenöse Sättigung SvO2 SvO2 = SaO2 VO2 CO Hb 1,34 folgt aus der Umwandlung von VO2 = CO (CaO2 CvO2) Sauerstoffverbrauch berechnet
ScvO 2 adequately reflects hypovolemia only high values [ 70%] can exclude inadequate oxygen delivery is no general estimate of SvO 2