Defining Optimal Perfusion during CPB. Carlo Alberto Tassi Marketing Manager Eurosets Italy

Transcription

1 Defining Optimal Perfusion during CPB Carlo Alberto Tassi Marketing Manager Eurosets Italy

2 It is a device able to monitor in a real time vital parameters and able to provide information regarding the transport and the consumption of oxygen during the extra corporeal circulation

3 LANDING PERMITS THE DISPLAY OF 21 PARAMETERS WITH VALUES UPDATED EVERY 5 SECONDS

4 What is the State of the Art? 1953 John Gibbon MD Since then, control of gas exchange and acid-base has always been done by reading and interpreting data from a device called GAS ANALIZER First intervention been successful thanks to the extra-corporeal circulation

5 What is the Gas Analizer (GA) intended for? The GA is an extemporaneous test that is done through a blood test usually arterial, which is scanned rapidly through a special laboratory instrument. The GA allows to measure the following parameters: Related to ventilation and gas exchange Related to acid-base balance and metabolism Related to plasma electrolytes

6 MORBIDITY and MORTALITY Patient undergoing cardiac surgery with Cardio Pulmonary By-Pass Acute renal failure: incidence 1-5% mortality 50%

7 MORBIDITY and MORTALITY Patient undergoing cardiac surgery with Cardio Pulmonary By-Pass gastro-intestinal Ischemia: complications from 0.3 to 2% mortality 12-67%

8 MORBIDITY and MORTALITY Patient undergoing cardiac surgery with Cardio Pulmonary By-Pass Brain damage or reversible in the first week: 50% incidence

9 MORBIDITY and MORTALITY Patient undergoing cardiac surgery with Cardio Pulmonary By-Pass - Severe disability or death from cerebral stroke: 1-5% incidence

10 Main Controversy related to perfusion and oxygenation during CPB The GA with ventilation and gas exchange parameters: 1. Provides information related to the diffusion of oxygen in the lung tissue; 2. It does not provide adequate quantitative information on the O 2 transport and especially relating to the O 2 consumption at tissue site.

11 Main Controversy related to perfusion and oxygenation during CPB It is common practice to calculate the theoretical flow of heart-lung machine using the following coefficient calculation: Q = B.S.A. x 2.4 (lt/min/m2) This condition does not take in consideration the CURRENT metabolic needs as well as having individual characteristics, can change several times during surgery.

12 WHAT CAN WE DO?

13 IMPORTANCE of Hb The hemoglobin (Hb) is a protein contained within red blood cells working as O2 carrier to transport O2all tissues. 1 gr di Hb binds 1.36 ml di O2/dl. considering Hb= 15 gr/dl, The O2 trasport will be 20 ml/dl.

14 O2 dissociation curve The 98% oxygen is transported through the hemoglobin (Hb). The 2% oxygen is transported dissolved in the plasma. The amount of Hb saturated oxygen (SO2) increases gradually with increasing PO2 with a typical sigmoidal pattern. The term PARTIAL PRESSURE (P) indicates the pressure exerted by a single gas in a gas mixture or in a liquid (Dalton's Law).

15 O2 requirement in the tissue Cardiac output (CO) in a man of medium height at rest is about 5 l / min. Under conditions of physical exertion the C.O. can increase up to liters / min. to meet the increased oxygen consumption of muscles. The oxygen consumption appears to be an individual factor primarily related to the type of metabolism of the individual.

16 O2 Saturation (SVO 2 ) Relationship between consumption and supply of oxygen. STD Value (SvO2): 60-80%

17 Controversial related to O2 requirement The oxygen consumption of a patient undergoing Cardiac Surgery corresponds to : sleeping? running?

18 Different approach to CPB The cellular activities require energy in the form of oxygen. If oxygen availability is limited alterations in metabolic functions occur with organ dysfunction, which if prolonged over time may become irreversible (hypoxic). To ensure proper functioning of cellular activities it is necessary a perfect balance between transport and consumption of oxygen. O 2 TRANSPORT = DO 2 O 2 CONSUPTION = VO 2 CELLULAR METABOLISM

19 hints of Physiology The amount of O2 available to the cells (DO2) is determined by the following factors: 1.RESPIRATORY SYSTEM which must ensure adequate arterial O2 saturation (SaO2 = %). 2.Concentration of HEMOGLOBIN (Hb). 1 g Hb binds 1:36 O2/dl ml. If we consider Hb = 15 g / dl, the transport of O2 will be 20 ml / dl. 3.CARDIAC OUTPUT (CO ml / min) ensures the transport of O2 in the blood. C.O. / B.S.A. = Cardiac Index (CI ml/min/m2) If we consider CO = 5 l / min, the total transport of O2 is 1000 ml / dl 4.SYSTEMIC VASCULAR RESISTANCE (SVR sec/cm5/m2 dyne *) represent the change in peripheral vascular tone. Together with the C.O. constitute the system to change the blood pressure. They regulate the peripheral microcirculation.

20 How to prevent the Cell damage during CPB? We should guarantee an adequate oxygen transport to tissues (DO2),to meet cells demands (VO2), through a direct action following factors: 1. Ensuring adequate blood oxygenation 2. Cardiac Output appropriate to the need 3. Increase the hemoglobin level 4. Adjustment of systemic vascular resistance 5. Temperature adjustment

21 LANDING = Fick s law Thanks to the sensors equipping LANDING monitor, it is possible to measure and calculate the following parameters: Oxygen Delivery Index DO 2 i = (0,0138 x Hb x SaO 2 ) x C.I. x 10 (ml/min/m 2 ) Oxygen Consumption Index VO 2 i = ((0,0138 x Hb x SaO 2 ) (0,0138 x Hb x SvO 2 )) x C.I.x10 (ml/min/m 2 ) Oxygen Extraction Index O 2 ERi = (SaO2 - SvO2) / SaO2 x100 (ml/m /m 2 ) Sistemic Vacular Resistance Index SVRi = MAP / C.I. X 80 dyne*sec/cm5/m 2

22 DO 2 and HCT DEEP HAEMODILITUION à lower DO 2 à lower O 2 supply to organ à increasing post-operative morbidity DO 2 has to be evaluated as func3on of Hct ONLY if the flow is constant!!

23 O 2 CONSUMPTION (VO 2 ) amount of oxygen used by the cells to satisfy the organism metabolic demand VO2 = CO x (CaO2- CvO2*) [ml/kg/min] *CvO2= ( Hb x 1,34 x SvO2) + (0,0031x PvO2)

24 O 2 EXTRACTION (O 2 ER) Represents the fraction of oxygen extracted from the tissues O 2 ER = VO 2 /DO 2 (approx 25%) If the CONTRIBUTION of OXYGEN (DO2) goes LOWER, with constant metabolism (VO2), the tissues increase the EXTRACTION OF OXYGEN

25 O 2 EXTRACTION in the TISSUE ARTERY VEIN PaO 2 100mmHg PvO 2 40 mmhg SaO % SvO 2 75 % CaO 2 20 ml/dl CvO 2 15 ml/dl

26 O 2 EXTRACTION in the TISSUE LOWER CARDIAC OUTPUT ARTERY VEIN PaO 2 100mmHg PvO 2 35 mmhg SaO % SvO 2 60 % CaO 2 20 ml/dl CvO 2 12 ml/dl

27 O 2 EXTRACTION in the TISSUE VO 2 INCREASING ARTERY VEIN PaO 2 100mmHg PvO 2 34 mmhg SaO % SvO 2 60 % CaO 2 20 ml/dl CvO 2 12 ml/dl

28 O 2 EXTRACTION in the TISSUE ANEMIA ARTERY VEIN PaO 2 100mmHg PvO 2 36 mmhg SaO % SvO 2 65 % CaO 2 14 ml/dl CvO 2 9 ml/dl

29 O 2 EXTRACTION in the TISSUE RESPIRATORY FAILURE ARTERY VEIN PaO 2 48 mmhg PvO 2 32 mmhg SaO 2 80 % SvO 2 55 % CaO 2 16 ml/dl CvO 2 11 ml/dl

30 O 2 EXTRACTION DURING CPB REDUCED CONSUMPTION (anesthesia, hypothermia, curarization, SHUNT A-V) ARTERY VEIN PaO 2 100mmHg PvO 2 58 mmhg SaO % SvO 2 88 % CaO 2 20 ml/dl CvO 2 18 ml/dl

31 DO 2 i Oxygen Delivery Index The O2 transport depends to following parameers: 1. CARDIAC INDEX 2. Hb 3. ARTERIAL SATURATION SaO2 DO 2 i = (0,0138 x Hb x SaO2) x C.I. x 10 (ml/min/m 2 ) 270ml/min/m 2 To increase the DO 2 : C.I ***** Hb *** SaO2*

32 VO 2 i Oxygen Consumption Index The Oxygen transpot depends on: CARDIAC INDEX Difference between ARTERIAL and VENOUS O2 CONTENT VO 2 i = ((0,0138 x Hb x SaO2) (0,0138 x Hb x SvO2)) x C.I.x10 (ml/ min/m 2 ) = 1/4-1/5 of DO 2 It is not possible direct action to change the VO2 A low VO2 value can be linked to: 1. tissue hypoxia 2. reduced oxygen demand without presence of hypoxia.

33 O 2 ERi Oxygen Extraction Index Both the DO2 VO2 when taken individually, they give poor information about the metabolic status of the patient. The O2ERi (ratio DO2/VO2), correlates the O2 transport with O2 consumption, thus, O2ERi expresses the ability of tissues to consume the available oxygen. O 2 ERi = (SaO2 - SvO2) / SaO2 x100 (ml/m /m 2 ) = 20-25%

34 Does DO 2 /VO 2 can be optimized? On what parameters can perfusionist work? 1. Change in Cardiac Output / Cardiac Index 2. Eventually increasing the hemoglobin (Hb) 3. Ensuring adequate oxygenation (PaO2/SaO2) 4. Control of body temperature. 5. Regulation of peripheral vascular resistance BALANCE of these parameters allows to obtain optimal O 2 ERi guaranteeing a proper perfusion even at the periphery.

35 Inadeguate DO 2 /VO 2 à cell suffering and Lactate production Under physiological conditions the O2 transport is adjusted to provide the adequate to O2 required. The oxygen consumption (VO2) is about 25% of DO2, and all the energy produced comes from "aerobic metabolism". When the metabolic demand increases, physiological mechanisms starts to increase either DO2 either the extraction fraction (O2ER). In the event of DO2 reduced, the CONSUMPTION is kept constant thanks to an increase of the O2ER, but the VO2 begins to decrease and the energy required can be produced only through the anaerobic metabolism.

36 DO 2 / VO 2 VO 2 (ml/min) 250 DO 2 Dipendency DO 2 CriHcal DO 2 Indipendency SvO 2 (%) O 2 ER (%) ,000 DO 2 (ml/min) The DO 2 in the plateau phase is independent of VO 2 When exceeds the critical point (anaerobic threshold) the DO2 and VO2 becomes dependent and the Do2 value decreases rapidly

37 VO 2 (ml/min) 250 DO 2 / VO 2 Versus LACTATE DO 2 Dipendency DO 2 CriHcal DO2 Indipendency SvO 2 (%) Lac (mmol/l) HYPERLACTATEMIA ,000 DO 2 (ml/min) In the case of strenuous exercise, or pathological conditions (sepsis, shock, heart failure) if the oxygen consumption (VO2) exceeds the transport (DO2) the production of lactic Lactate starts

38 Hyperlactatemia Lac>3mMoli(L

39 Hyperlactatemia Lac> 3mMoli/L Is an index of tissue hypoxia from inadequate perfusion (circulatory failure, cardiac shock, severe anemia). Numerous studies have shown an inverse correlation between the level of lactate and survival of critically ill patients. Recent studies have confirmed these results with association between an early increase in lactate and development of MOF (Multi Organ Failure). The duration and degree of hyperlactatemia are important predictors of morbidity and mortality. Hyperlactatemia remains therefore a reliable indicator for prognosing cellular suffering.

40 New approach to C.P.B.

41 TAYLORED CPB

42 TAYLORED CPB

43 TAYLORED CPB

44 Leteratures on DO 2 Ranucci M, Pavesi M, Mazza E, et al: Risk factors for renal dysfunction after coronary surgery: the role of cardiopulmonary bypass technique. Perfusion 9: , Fang WC, Helm RE, Krieger KH, et al. Impact of minimum hematocrit during cardiopulmonary bypass on mortality in patients undergoing coronary artery surgery. Circulation Nov 4;96(9 Suppl):II DeFoe GR, Ross CS, Olmstead EM, et al Lowest hematocrit on bypass and adverse outcomes associated with coronary artery bypass grafting. Northern New England Cardiovascular Disease Study Group. Ann Thorac Surg Mar;71(3): Swaminathan M, Phillips-Bute BG, Conlon PJ, et al: The association of lowest hematocrit during cardiopulmonary bypass with acute renal injury after coronary artery bypass surgery. Ann Thorac Surg 76: , Habib RH, Zacharias A, Schwan, et al. Adverse effects of low hematocrit during cardiopulmonary bypass in the adult: should current practice be changed? J Thorac Cardiovasc Surg Jun;125(6): Karkouti K, Beattie WS, Wijeysundera DN, et al. Hemodilution during cardiopulmonary bypass is an independent risk factor for acute renal failure in adult cardiac surgery. J Thorac Cardiovasc Surg 2005; 129: Habib RH, Zacharias A, Schwann, TA, et al. Role of Hemodilutional Anemia and Transfusion during Cardiopulmonary Bypass in Renal Injury After Coronary Revascularization: Implications on Operative Outcome Crit Care Med (in press)

45 TAYLORED CPB SaO 2 Hgb FLOW DO 2 PUMP FLOW TAILORED DO 2 >270 ml/min/m 2

46 Main GOAL: DO 2 > 270 ml/min/m 2 Calculated DO 2 = (1,34 x Hgb x SatA x Qb/100 ) / BSA YES DO 2 >270ml/min/m 2? Hct >25%? NO Continue CPB wthout adjustment a. Diuretic b. Haemofiltration c. Transfusion Increase Flow If Lactate > 2mmol/l Attention to: Flow, Hgb, Arterial Pressure, Temperature, Glycemia

47 LANDING allows to DISPLAY 21 PARAMETERS with VALUES UPDATED EVERY 5 SECONDS

48 LANDING items Monitor 10.5 inch touch screen Probes Arterial and Venous Inteface cables for pressure transducer Fllow meter ultrasonic

49 LANDING: main screen Calculated Measured

50 LANDING: Body Surface Area calculation

51 LANDING: working mode DO 2 i VO 2 i O 2 ERi weaning

52 LANDING non invasive A-V probes

53 LANDING: select a screen

54 LANDING: modifiable screen

55 LANDING: modifiable screen

56 LANDING: during CPB

57 LANDING: story board

58 LANDING: select parameters to Show, H-Y

59 LANDING: alarm setting

60 LANDING: value fine tuning

61 LANDING download data via USB

62 TAHE HOME MESSAGE Defining Optimal Perfusion during CPB DO 2 VO2

63 Thanks