Revisiting Fluid Challenge: New Ideas and New Developments

1. Revisiting Fluid Challenge: New Ideas and New Developments D. John Doyle MD PhD FRCPC Cleveland Clinic Foundation March 2003

2. Outline • Physiology • Monitoring the Need for Fluid Resuscitation • The Classical Fluid Challenge • New Approaches to Fluid Challenge • Systolic Pressure Variation

3. Physiology

4. ECF and ICF Volumes • ECF Volume= 1/3 x total body water • ICF Volume = 2/3 x total body water • ECF Volume = Plasma Volume + Interstitial Volume ... from Moyer’s Fluid Balance

5. Fluid Compartments • Total Body Water 0.6 L/kg • 2/3 Intracellular (ICF) • 1/3 Extracellular (ECF) • ICF Volume (0.4 L/kg) • ECF Volume (0.2 L/kg) • Plasma Volume (0.05 L/kg) • Interstitial Volume (0.15 /kg) Ratio of plasma volume to interstitial volume is 1-to-3 [rationale for 3-to-1 replacement of blood losses with crystalloid]

6. Intravascular Volume • Influences: • LV Filling • RV Filling • Cardiac Output • Blood Pressure • Oxygen Transport • Equilibrates with interstitial compartment according to Starling’s Law

7. Plasma Volume Expansion “Volume expansion is frequently used in critically ill patients to improve hemodynamics. Because of the positive relationship between ventricular end-diastolic volume and stroke volume, the expected hemodynamic response to volume expansion is an increase in right ventricular end-diastolic volume (RVEDV), left ventricular end-diastolic volume, stroke volume, and cardiac output.” Michard F. Teboul JL. Predicting fluid responsiveness in ICU patients: a critical analysis of the evidence.Chest. 121(6):2000-8, 2002 Jun.

8. Clinical Situations Often Requiring Plasma Volume Expansion • Management of patients with hemorrhage (eg, GI bleed, ruptured AAA, cardiac redo cases gone bad, IVC tear, SVC tear ) • Surgery, especially with large blood losses or large third space losses, such as liver transplantation or spinal correction surgery • Management of burn patients • Perioperative management of trauma patients • Management of cardiopulmonary bypass • Management of patients with “sepsis syndrome”

9. Fluid Therapy • Empirical rules exist to help in clinical management (maintenance IV requirements formula, Parkland burn protocol) • Goal: to maintain intravascular volume and tissue perfusion • Guidance: Monitored end pointsUrine output, orthostatic BP changes, CVP, PCWP (wedge pressure)

10. The Ideal Plasma Volume Expander • Inexpensive • No special storage problems; long shelf life • Can be made in bulk using existing industrial processes • Free of pathogens • Nontoxic • Crystalloid vs Colloid

11. Effects of Fluid Administration  PV = Vi X PV Vd PV = plasma volume (e.g 3 liters) Vi = volume infused Vd = volume of distribution= 42 for D5W, 14 for Ringer’s

12. Effects of Fluid Administration Replace 500 cc blood loss with D5W  PV = 500 ml PV = 3 Vd 42 Vi = 7000 ml

13. Effects of Fluid Administration Replace 500 cc blood loss with RL  PV = 500 ml PV = 3 Vd 14 Vi = 2300 ml

14. Fluid Challenge Methods

15. Classical Fluid Challenge Methods AIMS • Systemic blood pressure improvement • Urine output improvement MONITORS • No filling pressure monitoring • Right-sided filling pressure monitoring (CVP) • Left-sided filling pressure monitoring (PCWP)

16. Giving a fluid challenge(one method) Step 1 – Administer 250 – 500 ml IV over 5 - 15 min Step 2 - Re-check the CVP Step 3 - CVP raised by 2 cm H20? No -> Step 1 Yes -> Step 4 Step 4 - Clinically improved? No -> Challenge once more. If still no improvement get expert help. Yes -> Stop challenging. Adapted from http://www.medicalapproaches.com/html/book1/02blo0104.htm

17. Approach to Hypotension

19. Algorithm for intraoperative colloid administration. BP = blood pressure HR = heart rate Hct = hematocrit CVP = central venous pressure From: Gan Anesth Analg Volume 88 May 1999 pp. 992-998

20. Case for CVP • Under normal circumstances, if you have a low CVP, chances are you have a low PCWP. • A CVP above 10 mm Hg indicates that the patient is likely not hypovolemic (although, fluid administration may be required for other reasons). • An elevated CVP is a nonspecific marker for the presence of disease.

21. Case Against CVP • CVP measurements cannot be considered a perfect replacement for pulmonary artery catheterization. • CVP may not accurately reflect pulmonary artery occlusion pressure in patients with right ventricular failure and other conditions. • Insertion of a CVP line is invasive and can lead to complications, such as hemorrhage, infection, pneumothorax, and air embolism.

22. United States Department of DefenseEmergency War Surgery NATO Handbook. Part II: Response of the Body to Wounding. Chapter IX: Shock and Resuscitation Replacement Therapy Peer Review Status: Internally Peer Reviewed The shock casualty should be given 1,000-2,000 cc of lactated Ringer's solution, infused as rapidly as possible. Another rule of thumb is an initial fluid challenge of 10-25 ml/kg given over a ten minute period. Some will respond promptly and remain stable with only this therapy. If the hemorrhage has been severe or is ongoing, the response will usually be only transient, but nevertheless may allow time for typing and crossmatching of blood. Lactated Ringer's Solution, in addition to providing a rapid increase in circulating volume, will begin the correction of the reduced extracellular volume space resulting front compensatory fluid shifts induced by the shock slate. Crystalloid solution rapidly equilibrates between the intravascular and interstitial compartments For this reason, adequate restoration of hemostatic stability may require large volumes of Ringer's lactate. It has been empirically observed that approximately 300 cc of crystalloid is required to compensate for each 100 cc of blood loss. This 3:1 rule is a good beginning point for fluid resuscitation, but obviously is not a hard and fast rule for those with massive hemorrhage. If the 3:1 ratio were adhered to in a casualty requiring 5,000 cc of blood replacement, inundation would result. About 3,000-4,000 cc of Ringer's lactate seems reasonable. http://www.vnh.org/EWSurg/ch09/09ReplacementTherapy.html

23. SpecialOpsMedicine.Com Training is conducted at the Joint Special Operations Medical Training Ctr. (JSOMTC). Training is 55 weeks long, of which 44 weeks are solely dedicated to medical training.

24. http://www.specialopsmedicine.com/trauma_pearls_of_wisdom.htmhttp://www.specialopsmedicine.com/trauma_pearls_of_wisdom.htm • The procedure for determining the results of the fluid challenge is as follows: • a. Obtain a complete set of baseline vitals, to include an accurate BP. • b. Initiate at least 1 large bore IV for the purpose of administering fluid. • c. Infuse 1 liter of fluid and retake the patient’s BP, if the BP responds with a 10mm increase in systolic pressure, continue to monitor the BP every 5 minutes for 15 minutes. If the BP holds, this patient is considered a rapid responder, resuscitate the patient to a systolic pressure of 90mm Hg. • If the BP responds initially with an increase of more than 10mm Hg systolic, but drops back down during the 15-minute period, this patient is considered a transient responder. The patient will be treated by maintaining a carotid pulse and monitoring the patient’s mental status. Ideally, the therapeutic goal of controlled shock is to reach 70mm Hg systolic and a pulse <120 BPM with a response to verbal stimuli. After 30 minutes, initiate mini fluid challenges of pressure. If the BP remains stable, continue with the 500cc bolus, or with any of the subsequent boluses, continue with "controlled shock" management if possible for 30 more minutes then try the mini fluid challenge again. Continue with this therapy for transient response until the patient is evacuated or the patient is able to achieve 90mm systolic. • If the BP doesn’t respond to the initial fluid challenge, this patient is considered a non-responder. Keep the patient’s IV and TKO regardless of the BP, monitor and maintain the patient as best as possible for 30 minutes. Then initiate the same mini fluid challenge therapy as you would for the transient responder, only this time, if the patient responds, do not raise the BP above 80mm Hg. Maintain this patient somewhere between 70-80mm Hg until he can be evacuated.

25. The procedure for determining the results of the fluid challenge is as follows: a. Obtain a complete set of baseline vitals, to include an accurate BP. b. Initiate at least 1 large bore IV for the purpose of administering fluid. c. Infuse 1 liter of fluid and retake the patient’s BP, if the BP responds with a 10mm Hg increase in systolic pressure, continue to monitor the BP every 5 minutes for 15 minutes. If the BP holds, this patient is considered a rapid responder, resuscitate the patient to a systolic pressure of 90mm Hg.

26. If the BP responds initially with an increase of more than 10mm Hg systolic, but drops back down during the 15-minute period, this patient is considered a transient responder. The patient will be treated by maintaining a carotid pulse and monitoring the patient’s mental status. Ideally, the therapeutic goal of controlled shock is to reach 70 mm Hg systolic and a pulse <120 BPM with a response to verbal stimuli. After 30 minutes, initiate mini fluid challenges of pressure. If the BP remains stable, continue with the 500cc bolus, or with any of the subsequent boluses, continue with "controlled shock" management if possible for 30 more minutes then try the mini fluid challenge again. Continue with this therapy for transient response until the patient is evacuated or the patient is able to achieve 90mm systolic.

27. If the BP doesn’t respond to the initial fluid challenge, this patient is considered a non-responder. Keep the patient’s IV and TKO regardless of the BP, monitor and maintain the patient as best as possible for 30 minutes. Then initiate the same mini fluid challenge therapy as you would for the transient responder, only this time, if the patient responds, do not raise the BP above 80mm Hg. Maintain this patient somewhere between 70-80mm Hg until he can be evacuated.

28. http://www.davidclark.com/MAST/medical.shtml

29. New Approaches to Fluid Challenge AIMS • Systemic blood pressure improvement • Urine output improvement MONITORS • CO • LVSW • LVEDA • Systolic pressure variation

30. Predicting Fluid Responsiveness in ICU Patients Only 40 to 72% of critically ill patients have been shown to respond to volume expansion by a significant increase in stroke volume or cardiac output in studies designed to examine fluid responsiveness. This finding emphasizes the need for predictive factors of fluid responsiveness in order to select patients who might benefit from volume expansion and to avoid ineffective or even deleterious volume expansion (worsening in gas exchange, hemodilution) in nonresponder patients, in whom inotropic and/or vasopressor support should preferentially be used. Michard F. Teboul JL. Predicting fluid responsiveness in ICU patients: a critical analysis of the evidence.Chest. 121(6):2000-8, 2002 Jun.

31. Echocardiographic Measurement of LVEDA The echocardiographic measurement of LVEDA has been shown to reflect more accurately the left ventricular preload when compared with PAOP, and to improve the ability to detect changes in left ventricular function caused by acute blood loss. Thys DM, Hillel Z, Goldman ME, et al. A comparison of hemodynamic indexes derived by invasive monitoring and two-dimensional echocardiography. Anesthesiology 1987; 67:630-634 Cheung AT, Savino JS, Weiss SJ, et al. Echocardiographic and hemodynamic indexes of left ventricular preload in patients with normal and abnormal ventricular function. Anesthesiology 1994; 81:376-387

32. Bivariate plots compare the effect of fluid volume on end-diastolic area (EDA), cardiac output (CO), left ventricular stroke work (LVSW), and pulmonary capillary wedge pressure (PCWP). Note the similar peaks for EDA, CO, and LVSW indicating that when EDA fails to change in response to fluid administration there is likewise no increase in CO or LVSW. No peak is evident for PCWP. From: Swenson: Anesth Analg, Volume 83(6).December 1996.1149-1153 Swenson Study

37. Systolic Pressure Variation Systolic pressure variation (SPV) is the cyclic fluctuation in systolic blood pressure that occurs during respiration. Increased SPV has long been recognized as an indicator of hypovolemia. Several recent studies have shown a correlation between SPV and left ventricular end-diastolic volume.

38. Systolic Pressure Variation Plot of airway pressure (top) and arterial blood pressure (point by point) against time. Notice how there is a dip in systolic blood pressure with each period of expiration, followed by a rise in pressure with inspiration.

39. Systolic Pressure Variation Plot of airway pressure and systolic blood pressure against time. By plotting only the systolic pressure instead of the full pressure wave, the effect of airway pressure on systolic pressure is made more evident.

40. Systolic Pressure Variation Dividing total SPV into two components, known as Up and Down, enhances the usefulness of SPV monitoring. Up is the peak systolic pressure minus the baseline systolic pressure measured during apnea. Down is the trough systolic pressure minus the baseline. It turns out that changes in Down are particularly sensitive indicators of left ventricular filling.

41. Arterial pressure records are shown during mechanical and spontaneous ventilation at baseline and after 1000 mL blood removal. The difference between the end-expiratory systolic pressure and the minimum systolic pressure over a respiratory cycle defines Delta down. The difference between the end-expiratory systolic pressure and the maximum systolic pressure over a respiratory cycle defines Delta up. Note that Delta down is associated with mechanical exhalation and spontaneous inhalation. Systolic pressure variation is the difference between the maximum and minimum systolic pressure over a respiratory cycle. Rooke GA, Schwid HA, Shapira Y: The effect of graded hemorrhage and intravascular volume replacement on systolic pressure variation in humans during mechanical and spontaneous ventilation. Anesth Analg 1995; 80:925-32

44. Systemic arterial blood pressure curve recorded in one patient before (A) and after 500 ml (B) and 1,000 ml (C) administration of hydroxyethylstarch. The difference between the maximal systolic pressure and the minimal systolic pressure during one cycle of mechanical breath defines the systolic pressure variation (SPV). The value of the systolic arterial pressure (SAP) during a short period of end-expiratory pause is used as a reference pressure to measure the delta up (dUp) and delta down (dDown) components of the SPV. The difference between the systolic pressure during end-expiratory pause and the maximum systolic pressure defines dUp. The difference between the systolic pressure during end-expiratory pause and the minimum systolic pressure defines dDown. EDAI = left ventricular end-diastolic area index. HR = heart rate; MAP = mean arterial pressure; PAOP = pulmonary artery occlusion pressure; SVI = stroke volume index. From: Tavernier: Anesthesiology, Volume 89(6).December 1998.1313-1321

45. Baseline

46. 500 ml HES

47. 1000 ml HES

48. Receiver operating characteristic (ROC) curves comparing the ability of the pulmonary artery occlusion pressure (PAOP), the left ventricular end-diastolic area index (EDAI), and the delta down component (dDown) of the positive pressure ventilation-induced arterial systolic pressure variation to discriminate between positive (>or= to 15% increase in stroke volume index [SVI]; n = 21) and negative (< 15% increase in SVI; n = 14) responses to a subsequent volume-loading step in 15 patients. The area under the ROC curve for dDown is greater than those for EDAI (P = 0.01) and PAOP (P = 0.001). There is no significant difference between EDAI and PAOP (P = 0.39). From: Tavernier: Anesthesiology, Volume 89(6).December 1998.1313-1321

49. Systolic Pressure Variation • Perel A, Pizov R, Cotev S. Systolic pressure varation is a sensitive indicator of hypovolemia in ventilated dogs subjected to graded hemorrhage. Anesthesiology 1987; 67:498-502 • Tavernier B, Makhotine O, Lebuffe G, Dupont J, Scherpereel P. Systolic pressure variation as a guide to fluid therapy in patients with sepsis-induced hypotension. Anesthesiology 1998; 89: 1313-1321 • Editorial. Less is more...using systolic pressure variation to assess hypovolaemia. Br. J. Anaesth. 1999 83: 550-551. • Clemente. A virtual instrument (VI) for haemodynamic management in ICU and during surgery. Journal of Medical Engineering & Technology, Volume 24, Number 3, (May/June 2000), pages, 111-116 • D. John Doyle, Sven Budwill, Patrick Mark, Aamer Shujah. Application of Contourography and synchronous averaging to the blood pressure waveform. Journal of Clinical Engineering. Vol. 22, No. 3, pp. 179-187, 1997 • Soncini M. A computerized method to measure systolic pressure variation in mechanically ventilated patients. J Clin Monitoring Comput 2002; 17:141-146.

50. Static Measurements • RAP and PAOP (PCWP) are measured at end-expiration without ventilator disconnection or removal of PEEP. • RVEDV is calculated from the measurement of right ventricular ejection fraction and cardiac output by using a fast-response thermistor pulmonary artery catheter as follows: RVEDV = (cardiac output/heart rate)/right ventricular ejection fraction. • RVEDV may also be evaluated by cardiac scintigraphy. • LVEDA is measured by transesophageal echocardiography using the transgastric short-axis view of the left ventricle.