Fluidos transoperatorios..pdf

8/13/2019 Fluidos transoperatorios..pdf

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Intraoperative Fluid Management and Choice of Fluids

Tong J. Gan, M.D. Durham, North Carolina

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OBJECTIVES

Review the physiology of fluid compartment, intraoperative fluid requirement and electrolyte composition of colloids andcrystalloids. Discuss the choice of fluids and present data on the impact of using different fluids on patient outcome. Review theliterature on the evidence of goal-directed intraoperative fluid management strategy. Discuss the optimal use of colloids andcrystalloids for fluid management.

CASE PRESENTATIONINTRODUCTIONFluid management is an essential part of patient care in the perioperative period. Adequate plasma volume is essential inmaintaining cardiac output and hence tissue perfusion. Inadequate tissue perfusion is associated with poor outcome following

surgery.1Fluid management strategies have undergone several shifts over the past fifty years. Prior to the sixties, fluid restrictionduring the intraoperative period was widely practiced. In the early 1960s, it was demonstrated that major surgery and traumawere associated with fluid requirements that significantly exceeded the usual rate of fluid maintenance.2As a result, fluidadministration became less restrictive. A decade later, the choice of fluid became the subject of intense debate, and continued till

today. In the late eighties and early nineties, the concept of achieving a supranormal oxygen delivery attracted much interest.More recently, goal directed fluid management appear to show benefits in surgical settings. The last few years saw the

development of new colloid solution, with its physical characteristics and its balanced electrolyte carrier.

FLUID COMPARTMENTSAccurate replacement of fluid deficits requires an understanding of the distribution volume of body fluids. About 60% of a

humans body weight is made up of water. For a person weighing 70 kg, total body water (TBW) is about 42 L. The total body

water exists within discreet but dynamic fluid compartments. Two thirds of the TBW (28 liters) is intracellular water. Theremaining third (14 liters) in the extracellular compartment is divided into the intravascular (5L) and extravascular (9L)compartments. Blood is composed of around 60% plasma (extracellular compartment) and 40% red and white blood cells and

platelets (intracellular compartment).3Plasma consists of inorganic ions (predominantly sodium chloride), simple molecules such

as urea and larger organic molecules (predominantly albumin and the globulins) dissolved in water. Interstitial fluid bathes thecells and allows metabolic substrates and wastes to be diffused between the capillaries and cells in the tissue. Excess freeinterstitial fluid enters the lymphatic channels and is ultimately returned to the plasma. The majority of the interstitial water is not

free, but exists within a proteoglycan matrix in a gel form. This arrangement allows for easy diffusion of solutes through theinterstitium, but significantly retards bulk water flow. The transcellular fluids are extracellular and extravascular and includethe cerebrospinal fluid, aqueous humor, pleural, pericardial, peritoneal and synovial fluids.

Colloid Oncotic Pressure and Fluid FluxColloid Oncotic Pressure (COP) is the osmotic pressure exerted by the macromolecules (the colloid molecules). This can bemeasured using a membrane transducer system in which the membrane is freely permeable to small ions and water but largelyimpermeable to the colloid molecules. The membrane pore size and the molecular size distribution of the colloid being studied

will dictate the measured value. The molecular size distribution of a colloid in solution is commonly described as a ratio of themeasured COPs across two membranes with different pore sizes - e.g. the pressure across a membrane with a nominal 50

Kilodalton pore size compared with the pressure across a membrane with a nominal pore size of 10 Kilodalton: theCOP50/COP10 ratio.

4Solutes that can pass freely across a semi-permeable membrane do not generate any oncotic pressure - they

are effectively a component of the solvent with respect to that membrane. Where membranes are selectively permeable to solutesthe water content of the fluid compartments is dictated by solute distribution as water moves down any osmotic pressure gradientto produce isotonicity.

Starling in 1896 first described the forces affecting the flux of fluid across the capillary membrane.5These forces can be

expressed in the following equation:

QV=K[(PC-PT) - !C("C-"T)]

in which QV= total flow of fluid across the capillary membrane; K = fluid filtration coefficient; PC= capillary hydrostatic

pressure; PT= interstitial hydrostatic pressure; !C= reflection coefficient; "C= capillary COP (plasma); "T= interstitial COP.The filtration coefficient is a function of the permeability and surface area of the capillary bed in question. The numeric valuerepresents the net volume of fluid crossing the capillary membrane under a specific set of conditions. The reflection coefficient isa mathematical expression (from 0 to 1) of the capillary membranes permeability to a particular substance. Thus the reflection

coefficient will vary with both the tissue bed and substance in question. If a substance is completely permeable to the capillarymembrane, the reflection coefficient will be 0; if it is totally impermeable, the coefficient will be 1. For protein, the approximate


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reflection coefficients for liver, lung, and brain are 0.1, 0.7, and 0.99, respectively.6When a pulmonary insult creates a leakycapillary state, the protein-lung reflection coefficient may decrease to approximately 0.4.7The reflection coefficient for albumin,the source of 60% of the normal oncotic pressure in the pulmonary circulation, is approximately 0.7.

The composition of administered fluids will therefore dictate their distribution. Pure water expands all body fluid compartmentsand therefore provides minimal expansion of the intravascular volume. Intravenous infusion of an isotonic solution of sodiumchloride expands only the extracellular compartment and will increase intravascular volume by about one fifth of the volumeinfused. Colloidal solutions containing large molecules are maintained within the circulation, at least initially, and so provide

greater intravascular volume expansion per unit volume infused. Lamke and Liljedahl8

demonstrated that 90 minutes followinginfusion of 1000 mL of 6% hetastarch, albumin or saline in postoperative surgical patients, 75%, 50% and


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endothelial system. Pentastarch 10% has a good initial volume-expanding capacity of 1.5 times the infused volume. About 90%is eliminated within 24 hours and most is undetectable after 96 hours. In critically ill patients, pentastarch has been found to beequivalent to albumin for fluid resuscitation.13

AlbuminAlbumin is a naturally occurring plasma protein composed of 584 amino acid residues. The molecular weight of albumin rangesfrom 66,000 to 69,000 depending on the technique of measurement.14The molecule is highly soluble and carries a strongnegative charge at physiological pH. Consequently, albumin migrates in the electrical fields. Depending on the salt and buffer

concentration of the plasma, albumin is isoelectric in the pH range of 4.4 and 5.4. In serum, albumin is in part bound to eithercations or anions. This property accounts for its role as a carrier protein for the transport and activation of drugs, hormones,

enzymes, fatty acids, amino acids, bilirubin and other metabolites. The half-life of circulating albumin is approximately 18 to 20days.

Albumin provides approximately 70% of the plasma colloid oncotic pressure in normal human subjects. Human albumin is

available for infusions as either 5% or 25% solution. The 5% solution contains 50 g albumin/L physiological salt solution and hasa COP of about 20 mmHg. The 25% solution contains 12.5 g albumin in 50 mL buffered diluent containing 130-160 mmol/L ofsodium. The 5% solution is approximately iso-oncotic, whereas the 25% solution is markedly hyperoncotic.

Plasma protein fraction (PPF) is a 5% solution of selected proteins prepared from pooled human blood, serum, or plasma. Itundergoes the same pasteurization process used for albumin and is a mixture of proteins consisting mostly of albumin in anamount equal to or greater than 83% of the total protein composition. The two solutions are similar in costs, and hence are usedinterchangeably.

DextransDextrans are high molecular weight D-glucose polymers linked by alpha1,6 bonds into predominantly linear macromolecules.They are biosynthesized commercially from sucrose by the B512 strain of leuconostoc mesenteroides using the enzyme dextran

sucrase.15This produces a high molecular weight dextran that is then cleaved by acid hydrolysis and separated by repeatedethanol fractionation to produce a final product with a relatively narrow molecular weight range. The products in current clinicaluse are described by their MWn: Dextran 40 and Dextran 70 having MWns of 40000 and 70000 dalton respectively.4

Dextrans, like all the other semisynthetic colloids, are polydisperse with 90% of the molecules of Dextran 40 having molecularweights between 10000 and 80000 dalton. The renal threshold for Dextrans is between 50000 and 55000 dalton. Molecules with

a MW less than this threshold are freely filtered at the glomerulus and molecules with a MW less than 15000 have a clearancesimilar to creatinine. Approximately 70% of an administered dose of Dextran 40 will be excreted into the urine within 24 hours.Larger molecules are excreted through the gut or phagocytozed by cells of the reticuloendothelial system where they are eithermetabolized by endogenous dextranases or recirculated into the systemic circulation.16

Infusions of hyperosmotic-hyperoncotic solutions such as hypertonic saline dextran have been shown to be very effective in

expanding plasma volume rapidly. The intravascular volume expansion efficiency, defined as milliliter plasmaexpansion/milliliter fluid infused was 7 and 20 folds at 30 and 60 min after infusion, respectively when hypertonic saline dextranwas compared with LR.17

Other ColloidsGelatins are prepared by hydrolysis of bovine collagen. The commonly available preparations are succinylated gelatin(Gelofusin) which is presented in isotonic saline and urea linked gelatin - polygeline (Haemaccel) which is presented in an

isotonic solution of sodium chloride with 5.1 mmol/L potassium and 6.25 mmol/L calcium.18

SALINE VS. BALANCED ELECTROLYTE BASED FLUIDSColloids and crystalloids may be divided into whether they are formulated in 0.9% sodium chloride or a variety of balanced

electrolyte solutions. Lactated Ringers and Normosol solutions consist of a number of electrolytes that are present in the plasma,

whereas 0.9% saline is made up of only sodium and chloride. A new hydroxyethyl starch, Hextend$, is formulated in abalanced electrolyte solution not dissimilar to those present in lactated Ringers solution. Recent studies have focused on the

differences between administering saline versus balanced electrolyte solutions to animals and humans. In a transplantedgreyhound kidney model, infusion of hypertonic sodium chloride containing fluid (saline or ammonium chloride solution)resulted in progressive renal vasoconstriction and falls in the glomerular filtration rate and renal blood flow. This fall isindependent of the renal nerves, and is potentiated by prior salt depletion and correlated strongly with renal tubular chloride.19


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Acid Base Balance and Renal OutcomeIn a human volunteer crossed-over study, Williams and colleagues20found a significantly higher incidence of subjective mentalchanges, abdominal discomfort, as well as a significant delay of time to first urination, in the group that received 50 mL/kg of0.9% sodium chloride over 1 hr compared with the same volume of lactated Ringers solution. Sceingraber et al. demonstrated a

significant hyperchloremic acidosis at the end of surgery in patients undergoing major gynecological hysterectomies when 0.9%sodium chloride was used as the intraoperative resuscitative fluid. The group that received lactated Ringers had a normal acid-

base balance. Interestingly, there was a trend towards greater estimated blood loss and lower urine output in the 0.9% sodium

chloride group. The perioperative use of balanced electrolyte solutions (Hartmanns solution$and Hextend$) was associated

with lower incidence of hyperchloremic metabolic acidosis and better gastrointestinal mucosal perfusion compared with sodiumchloride based solutions (0.9% saline and Hespan$). Other studies have demonstrated the predictability of acidosis followingrapid intraoperative administration of saline based fluid.21-24

The type of fluid administered during the perioperative period could have a significant impact on several clinically relevantoutcomes following cardiac surgery. Serum creatinine levels were elevated by about 50% on postoperative day 2 in the groups

that received either 6% hetastarch in saline or albumin (saline based), but not Hextend$or lactated Ringers groups. These

differences persisted up to postoperative day 7 and were mirrored by changes in lower creatinine clearance and urinary flow rate.

More patients in the Hespan$group required postoperative hemodialysis.

Hemostatic Effects

The choices of fluid administered intraoperatively can result in differences in the coagulation effects. Hespan$in larger volume(>20 mL/kg) has been associated with reduced levels of the coagulations factors, e.g., fibrinogen, Factor VIII, and von

Willebrands factor and reduced platelet function, beyond the effect of hemodilution. Crystalloid administration, however, isassociated with a hypercoagulative state.

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A recent study demonstrated a better thromboelastographic coagulation profile when larger volumes of Hextend$(>20 mL/kg)

was used compared with equivalent volumes of 6% hetastarch in saline (Hespan$).26The use of Hespan$was associated with a

hypocoagulable state with prolongation of both their r time and k time and a reduction in MA on thromboelastography. Thishypocoagulable state continued into the first 24 hours postoperatively with further increases in the r time and k time.27Lactated

Ringers solution, however, was associated with a hypercoagulable state.27,28The TEG profiles with respect to Hextend$showed

the least change at the end of surgery and 24 hours after surgery.28In another study when Hextend$was compared with albumin,

there appeared to be no differences in the levels of Factor VIII, von Willebrands factors and platelets up to 24 hours followingmajor urological surgery.29Similar findings were demonstrated by Bennett-Gurrero et al.27in patients undergoing cardiacsurgery. Patients who received 6% hetastarch in saline required more units of red cells, fresh frozen plasma, and platelets

transfusion and more patients in this group returned to the operating room for surgical reexploration secondary to

hypocoagulopathy, when compared with similar groups receiving lactated Ringers, albumin or Hextend$.

GOAL DIRECTED FLUID ADMINISTRATION

Hypovolemia is common among patients scheduled for surgery. In addition to the inevitable losses in the perioperative perioddue to surgical trauma, evaporation, and the use of dry anesthetic gases, the majority of patients are routinely required to starvefor a minimum of 6 hours preoperatively to reduce the risk of acid aspiration syndrome.30Hypovolemia during the perioperative

period is associated with a significant increase in postoperative morbidity and mortality, ranging from postoperative nausea and

vomiting31

to more serious complications such as organ dysfunction32

, and prolongation of hospital stay.32,33,34

Since the late 1950s a succession of authors have described an association between perioperative cardiac output and survivalfollowing major surgery: the survivors exhibiting higher values than the non-survivors.35-37. In 1988 Shoemaker was the first to

test this hypothesis in a randomized controlled clinical trial (RCT).38In a complex study he demonstrated that targeting specificvalues for cardiac index, oxygen delivery and oxygen consumption, using fluids and inotropes to achieve these goals, resulted ina reduction in mortality and morbidity.

Since then a number of single center randomized controlled trials have been conducted, the majority of which support thisoriginal positive result. Five studies have used the same hemodynamic goals as the original study by Shoemaker. Two of thesewere large (>100 patient) studies on high-risk general surgical and vascular patients and both demonstrated a statistically

significant reduction in mortality in the protocol groups.39,40Two were studies of major trauma surgery and were both conductedby the same group.41,42The first smaller study showed a trend towards reduction in mortality in the protocol group and this wasconfirmed by a statistically significant reduction in mortality in the protocol group in the second, larger trial. The fifth study inthis group was a small trial focusing on surgery for hepatobiliary carcinoma and demonstrated a reduction in liver failure and

hyperbilirubinemia although this was not their specified primary outcome variable.43

An older study using a similar strategy, inpatients undergoing hip fracture surgery also demonstrated a significant mortality reduction.

44


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Somewhat different results have been obtained in a series of studies in which patients presenting for major vascular or aorticsurgery were studied.45-47. The goals for cardiac index and oxygen delivery used in these trials were significantly lower and theoverall mortality for each trial was also low. These studies did not demonstrate a significant reduction in mortality, or in some

cases complications, however in one study there were more deaths in the protocol than control groups.47

Targeting mixed venous oxygen saturation (SvO2) as an indirect index of oxygen delivery has also been studied in two trials. The

first study in vascular patients failed to demonstrate a significant morbidity or mortality difference between control and protocol

groups.48

More recently a large Scandinavian study of patients undergoing elective coronary revascularizationdemonstrated a significant reduction in length of stay in those randomized to maintenance of SvO2 > 70% and lactate %2mmolL-1 when compared with controls.49

A number of published studies using intraoperative esophageal Doppler monitoring of cardiac output compared a stroke volumeoptimization algorithm with standard fluid management. In the first study patients with normal left ventricular functionundergoing coronary artery revascularization had a statistically significant reduction in length of both ICU and overall hospital

stay in the protocol group.32The second study, of elderly patients having hip prosthesis surgery also demonstrated a reduction inhospital length of stay in patients managed in the protocol group.33Neither of these studies were designed to demonstrate a

mortality difference. Gan and colleagues, in a recent study using a similar goal directed fluid administration algorithm alsodemonstrated a reduction in hospital stay and earlier return to tolerating solid food in the protocol group.

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The application of this management approach to patients with established critical illness have failed to show an outcome benefitfor patients in the protocol group51,52,53. Indeed in one study the intervention group had a higher mortality.52Taken together the

perioperative trials present an interesting picture. Many of the studies were not designed with mortality as a primary outcome

goal and several of those that were did not have adequate statistical power to detect a mortality reduction. However if all the trialsare grouped together and the control group mortality compared with the intervention group the results are striking. The crudedeath rates are 96/753 for the combined control groups and 36/814 for the combined protocol groups. In only two of 15 studies

was there greater mortality in the protocol group: in one study 5/72 patients died: 2/40 control and 3/32 protocol and in the other4/120 patients died: 1/60 control and 3/60 protocol47,48. The accumulated body of evidence relating to goal directed hemodynamic

perioperative management now includes at least 15 RCTS (Table 2) and 2 supportive meta-analyses.54,55

Table 2. Studies on perioperative goal directed hemodynamic management and outcome.

Year First Author n Surgery Tool Algorithm Outcome Result

1985 Schultz 70 Elective hip PAC Unclear Death Y

1988 Shoemaker 58 High risk major PAC DO2/VO2 Death Y

1991 Berlauk 89 Vascular PAC CI Cardiac Y

1992 Fleming 67 Trauma PAC CI/DO2/VO2 Death N

1993 Boyd 107 High risk major PAC DO2 Death Y1995 Bishop 115 Trauma PAC CI/DO2/VO2 Death Y

1995 Mythen 60 Cardiac EDM SV LOS Y

1997 Bender 104 Vascular PAC CI/SVR Complications N

1997 Sinclair 40 Elective hip EDM SV/FTc LOS Y

1997 Ziegler 72 Vascular PAC SvO2 Cardiac N

1998 Ueno 34 Liver PAC CI/DO2/VO2 Liver failure N

1998 Valentine 120 Aortic PAC CI/SVR Complications N

1999 Wilson 138 High risk major PAC DO2 Death Y

2000 Polonen 393 Cardiac PAC SvO2/Lactate LOS Y

2002 Gan 100 Mod. risk major EDM SV/FTc LOS Y

PAC=pulmonary artery catheter; EDM=esophageal Doppler monitor; DO2=oxygen delivery; VO2=oxygen comsumption; CI-

cardiac index; SV=stroke volume; SVR=systemic vascular resistance; FTc=corrected flow time; SvO2=venous oxygensaturation; LOS=length of stay; Y=positive outcome; N=negative outcome

COLLOIDS VS CRYSTALLOIDSArguments over the best choice of fluid for volume resuscitation have been hotly debated for more than 30 years. While all sidesagree that fluid resuscitation is fundamental in the management of hypovolemia there is disagreement as to which solutions to


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use. Crystalloid proponents point to the haemostatic derangement, the increased incidence of adverse drug reaction and thegreater risk of fluid overload occurring with colloidal fluids. The colloid lobby focuses on the large volumes of crystalloidrequired to achieve adequate resuscitation and on the resultant tissue edema and reduction in tissue oxygen delivery. There have

been three meta-analyses focusing specifically on this issue and with mortality as an endpoint.56-58The most recent of these

focused on 19 RCTs including 1315 patients and suggested an increase absolute risk of mortality of 4% with use of colloid forvolume replacement (95% confidence interval 0% to 8%). However these meta-analyses have been widely criticized for pullingtogether a large number of studies comparing a number of different solutions amongst diverse patient populations, for varyingindications. None of the original studies used mortality as a primary end point, the vast majority of studies included are of

albumin or dextran solutions and these two colloids contribute all the excess mortality. At present there is a lack of adequatestudies upon which to base a judgement on this question.

However, a recent study suggests that the quality of recovery may be superior when colloid/crystalloid combination was usedcompared with crystalloid alone in patients undergoing major non-cardiac surgery. Patients who received lactated Ringers alonehad higher incidence of nausea and use of rescue antiemetic, double vision, and complained of more severe pain

postoperatively.59

SUMMARYPerioperative fluid management has undergone significant advances over the past few decades. The choice of fluid and its

electrolyte composition are important considerations when replenishing plasma volume and other body fluid compartments. Thecoming decade will see an expansion of knowledge defining the role of goal directed fluid therapy in clinical practice and subtledifferences between colloids and crystalloids when used in the perioperative period.

REFERENCES

1. Mythen MG, Webb AR: Intra-operative gut mucosal hypoperfusion is associated with increased post-operative complications and cost.Intensive Care Medicine 1994; 20: 99-104

2. Shires T, Coln D, Carrico J, Lightfoot S: Fluid therapy in hemorrhagic shock. Arch Surg 1964; 1964: 688-93

3. Zalogo G, Prough DS: Fluids and Electrolytes, Clinical Anesthesia, 2nd Edition. Edited by Barash PG, Cullen BF, Stoelt ing RK. Philadelphia,Lippincott, 1992

4. Salmon JB, Mythen MG: Pharmacology and physiology of colloids. Blood Reviews 1993; 7: 114-205. Starling EH: On the absorption of fluids from the connective tissue spaces. J Physiol 1896; 9: 312

6. Wtiitmers LE, Bartlett M, Johnson JA: Estimation of capillary permeability coefficient of inulin in various tissues of rabbit. Microvasc Res

1976; 11: 67

7. Brigham KL: Mechansims of lung injury. Clin Chest Med 1982; 3: 98. Lamke LO, Liljedahl SO: Plasma volume changes after infusion of various plasma expanders. Resuscitation 1976; 5: 93-102

9. Hankeln K, Radel C, Beez M, Laniewski P, Bohmert F: Comparison of hydroxyethyl starch and lactated Ringer&s solution on hemodynamicsand oxygen transport of critically ill patients in prospective crossover studies. Critical Care Medicine 1989; 17: 133-5

10. Ernest D, Belzberg AS, Dodek PM: Distribution of normal saline and 5% albumin infusions in septic patients. Critical Care Medicine 1999;

27: 46-50

11. Treib J, Haass A, Pindur G, et al: All medium starches are not the same: influence of the degree of hydroxyethyl substitution of hydroxyethylstarch on plasma volume, hemorrheologic conditions, and coagulation. Transfusion 1996; 36: 450-5

12. Yacobi A, Stoll RG, Sum CY, et al: Pharmacokinetics of hydroxyethyl starch in normal subjects. Journal of Clinical Pharmacology 1982; 22:206-12

13. Rackow EC, Mecher C, Astiz ME, et al: Effects of pentastarch and albumin infusion on cardiorespiratory function and coagulation in patients

with severe sepsis and systemic hypoperfusion. Critical Care Medicine 1989; 17: 394-8

14. Tullis JL: Albumin. JAMA 1977; 237: 35515. Mishler JM: Synthetic plasma volume expanders--their pharmacology, safety and clinical efficacy. Clinics in Haematology 1984; 13: 75-92

16. Haljamae H: Volume substitution in shock. Acta Anaesthesiol Scand Suppl 1993; 98: 25-8

17. Tollofsrud S, Elgjo GI, Prough DS, et al: The dynamics of vascular volume and fluid shifts of lactated Ringer&s solution and hypertonic-

saline-dextran solutions infused in normovolemic sheep. Anesthesia & Analgesia 2001; 93: 823-31

18. Saddler JM, Horsey PJ: The new generation gelatins. A review of their history, manufacture and properties. Anaesthesia 1987; 42: 998-1004

19. Wilcox CS: Regulation of renal bloof flow by plasma chloride. J Clin. Invest 1983; 71: 726-735

20. Williams EL, Hildebrand KL, McCormick SA, Bedel MJ: The effect of intravenous lactated Ringer&s solution versus 0.9% sodium chloride

solution on serum osmolality in human volunteers. Anesthesia & Analgesia 1999; 88: 999-1003

21. Prough DS, White RT: Acidosis associated with perioperative saline administration: dilution or delusion? Anesthesiology 2000; 93: 1167-922. Waters JH, Bernstein CA: Dilutional acidosis following hetastarch or albumin in healthy volunteers. Anesthesiology 2000; 93: 1184-7

23. Rehm M, Orth V, Scheingraber S, et al: Acid-base changes caused by 5% albumin versus 6% hydroxyethyl starch solution in patients

undergoing acute normovolemic hemodilution: a randomized prospective study. Anesthesiology 2000; 93: 1174-8324. Liskaser FJ, Bellomo R, Hayhoe M, et al: Role of pump prime in the etiology and pathogenesis of cardiopulmonary bypass-associatedacidosis. Anesthesiology 2000; 93: 1170-3

25. Ruttmann TG, James MF, Viljoen JF: Haemodilution induces a hypercoagulable state. Br J Anaesth 1996; 76: 412-4.

26. Gan TJ, Bennett-Guerrero E, Phillips-Bute B, et al: Hextend$, a physiologically balanced plasma expander for large volume use in major

surgery: a randomized phase III clinical trial. Hextend$Study Group. Anesthesia & Analgesia 1999; 88: 992-8


7/7

122

Page 7

27. Bennett-Guerrero E, Frumento RJ, Mets B, Manspeizer HE, Hirsh AL: Impact of normal saline based versus balanced-salt intravenous fluid

replacement on clinical outcomes: a randomized blinded clinical trial (Abstract). Anesthesiology 2001; 95: A147

28. Martin G, Wakeling H, El-Moalem H, et al: A prospective randomized comparison of thromboelastographic coagulation profile in patients

receiving Hextend$, 6% hetastarch in saline or lactated ringer&s during major surgery. (In press). J Thoracic Vas Surg 2002

29. Gan TJ, Wright D, Robertson C, Thomas D, Robertson K: Randomized comparison of the coagulation profile when Hextend$or 5% albumin

is used for intraoperative fluid resuscitation. Anesthesiology 2001; 95: A193

30. Anonymous: Practice guidelines for preoperative fasting and the use of pharmacologic agents to reduce the risk of pulmonary aspiration:

application to healthy patients undergoing elective procedures: a report by the American Society of Anesthesiologist Task Force on Preoperative

Fasting. Anesthesiology 1999; 90: 896-905

31. Yogendran S, Asokumar B, Cheng DC, Chung F: A prospective randomized double-blinded study of the effect of intravenous fluid therapyon adverse outcomes on outpatient surgery. Anesthesia & Analgesia 1995; 80: 682-6

32. Mythen MG, Webb AR: Perioperative plasma volume expansion reduces the incidence of gut mucosal hypoperfusion during cardiac surgery.

Archives of Surgery 1995; 130: 423-933. Sinclair S, James S, Singer M: Intraoperative intravascular volume optimisation and length of hospital stay after repair of proximal femoral

fracture: randomised controlled trial. BMJ 1997; 315: 909-1234. Bennett-Guerrero E, Welsby I, Dunn TJ, et al: The use of a postoperative morbidity survey to evaluate patients with prolonged hospitalization

after routine, moderate-risk, elective surgery. Anesthesia & Analgesia 1999; 89: 514-9

35. Shoemaker WC, Montgomery ES, Kaplan E, Elwyn DH: Physiological Patterns in Surviving and Non-Surviving Shock Patients. Use of

Sequential Cardiorespiratory Parameters in Defining Criteria for Therapeutic Goals and Early Warning of Death. Archives of Surgery 1973; 106:630-6

36. Boyd AR, Tremblay RE, Spencer FC, Bahnson HT: Estimation of Cardiac Output Soon After Cardiac Surgery With Cardiopulmonary

Bypass. Annals of Surgery 1959; 150: 613-25

37. Clowes GHA, Del Guerico LRM: Circulatory Response to Trauma of Surgical Patients. Metabolism 1960; 9: 67-8138. Shoemaker WC, Appel PL, Kram HB, Waxman K, Lee TS: Prospective trial of supranormal values of survivors as therapeutic goals in high-

risk surgical patients. Chest 1988; 94: 1176-86

39. Wilson J, Woods I, Fawcett J, et al: Reducing the risk of major elective surgery: randomised controlled trial of preoperative optimisation of

oxygen delivery. BMJ 1999; 318: 1099-10340. Boyd O, Grounds RM, Bennett ED: A randomized clinical trial of the effect of deliberate perioperative increase of oxygen delivery onmortality in high-risk surgical patients. JAMA 1993; 270: 2699-707

41. Bishop MH, Shoemaker W, Appel P, et al: Prospective, randomized trial of survivor values of cardiac index, oxygen delivery, and oxygen

consumption as resuscitation endpoints in severe trauma. J Trauma Injury Infect Crit Care 1995; 1995: 780-87

42. Fleming A, Bishop M, Shoemaker W, et al: Prospective trial of supranormal values as goals of resuscitation in severe trauma. Arch Surg

1992; 127: 1175-79

43. Ueno S, Tanabe G, Yamada H, et al: Response of patients with cirrhosis who have undergone partial hepatectomy to treatment aimed atachieving supranormal oxygen delivery and consumption. Surgery 1998; 1998: 278-86

44. Schultz RJ, Whitfield GF, LaMura JJ, Raciti A, Krishnamurthy S: The role of physiologic monitoring in patients with fractures of the hip. J

Trauma Injury Infect Crit Care 1985; 25: 309-16

45. Bender JS, Smith-Meek MA, Jones CE: Routine pulmonary artery catheterization does not reduce morbidity and mortality of electivevascular surgery: results of a prospective, randomized trial. Ann Surg 1997: 229-36

46. Berlauk JF, Abrams JH, Gilmour IJ, et al: Preoperative optimization of cardiovascular hemodynamics improves outcome in peripheral

vascular surgery. A prospective, randomized clinical trial. Annals of Surgery 1991; 214: 289-97; discussion 298-9

47. Valentine RJ, Duke ML, Inman MH, et al: Effectiveness of pulmonary artery catheters in aortic surgery: a randomized trial. J Vasc Surg

1998; 27: 203-1148. Ziegler DW, Wright JG, Choban PS, Flancbaum L: A prospective randomized trial of preoperative optimization of cardiac function in

patients undergoing elective peripheral vascular surgery. Surgery 1997; 122: 584-92

49. Polonen P, Ruokonen E, Hippelainen M, Poyhonen M, Takala J: A prospective, randomized study of goal-oriented hemodynamic therapy in

cardiac surgical patients. Anesth Analg 2000; 90: 1052-950. Gan TJ, Soppitt A, Maroof M, et al: Goal directed intraoperative fluid administration reduces length of hospital stay after major surgery.

Anesthesiology (In press) 2002

51. Yu M, Levy MM, Smith P, et al: Effect of maximizing oxygen delivery on morbidity and mortality rates in critically ill patients: a

prospective, randomized, controlled study. Crit Care Med 1993; 21: 830-38

52. Hayes MA, Timmins AC, Yau EH, et al: Elevation of systemic oxygen delivery in the treatment of critically ill patients. New England Journal

of Medicine 1994; 330: 1717-2253. Gattinoni L, Brazzi L, Pelosi P, et al: A trial of goal-oriented hemodynamic therapy in critically ill patients. SvO2 Collaborative Group. New

England Journal of Medicine 1995; 333: 1025-32

54. Boyd O, Hayes M: The oxygen trail: the goal. Br Med Bull 1999; 55: 125-39.

55. Heyland DK, Cook DJ, King D, Kernerman P, Brun-Buisson C: Maximizing oxygen delivery in critically ill patients: a methodologicappraisal of the evidence. Crit Care Med 1996; 24: 517-24

56. Choi PT, Yip G, Quinonez LG, Cook DJ: Crystalloids vs. colloids in fluid resuscitation: a systematic review. Critical Care Medicine 1999;

27: 200-1057. Schierhout G, Roberts I: Fluid resuscitation with colloid or crystalloid solutions in critically ill patients: a systematic review of randomised

trials. BMJ 1998; 316: 961-4.58. Velanovich V: Crystalloid versus colloid fluid resuscitation: a meta-analysis of mortality. Surgery 1989; 105: 65-71

59. Gan TJ, Moretti E, El-Moalem H, Mythen MG, Glass PSA: Intraoperative colloid administration improves the quality of patient recovery

after surgery. Anesthesiology 1999; 91: A1124

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