by Michael G Mythen, MBBS, MD, and Michael PW Grocott, BSc, MBBS, MD
Fluid management is a fundamental component of the care we give our patients undergoing surgery. Establishing intravenous access and setting up a bag of fluid to flow into a vein is so much a part of everyday working life that we rarely give it much thought. We each have our own personal rationale for our chosen pattern of fluid administration and we probably think that we have pretty standard, mainstream patterns of behavior in our care and deliver a good outcome for our patients. Yet a high degree of variability in both the type and amount of fluid that our patients receive during major surgery is repeatedly reported in the literature, and at the extremes is associated with poor outcome.1-3
For example, Lilot et al. recently published an analysis of clinical data from 6,000 patients undergoing intra-abdominal surgery at UC Irvine and Vanderbilt University Medical Centers.1 They reported the variation in crystalloid administration in a variety of uncomplicated elective intra-abdominal surgery cases with minimal blood loss. The mean “corrected crystalloid infusion rate” across all providers was 7.1 (SD 4.9) ml/kg/h. Individual provider means ranged from 2.3 to 14 ml/kg/h. They concluded that the “final regression model strongly favored personnel as predictors (of administered fluid volume) over other patient predictors.”1 Therefore, the major determinant in this particular study of how much fluid a patient received on the day of surgery was not a change in hemodynamic variables (heart rate, blood pressure), duration of surgery, or blood loss, but the particular anesthesia provider who had been assigned to do the case. In an applied example, the authors showed how a patient weighing 75 kg undergoing a 4-hour procedure with minimal blood loss could receive anywhere between 700 and 5400 ml of crystalloid during surgery, depending on which anesthesia provider had been allocated.1
More recently, Thacker et al. published a study describing fluid administration practices in a large cohort from the Premier Research Database including adult patients having colon, rectal, or primary hip or knee surgery.3 These investigators explored the relationship between intravenous fluid utilization on the day of surgery and outcomes. Regression models were developed to determine associations between liberal or restrictive day-of-surgery fluid volumes and the likelihood of various outcomes. When compared with the 50% of patients who received moderate volumes (middle 2 quartiles by volume of fluid administration), they found significant associations between liberal fluid administration (upper quartile) on the day of surgery and increased total costs (odds ratio 1.10-1.50) and length of stay (odds ratio 1.10-1.40) in all patients, as well as increased presence of postoperative ileus in patients undergoing colorectal surgery. They also observed that restrictive fluid utilization (lower quartile) was associated with worse outcomes.3
This seemingly chaotic, and certainly highly variable, administration of intravenous fluids is also seen in reports of randomized controlled trials. In 2 recent examples the range of “maintenance fluid” advocated in the protocols ranged between 10 ml/kg/hr of Lactated Ringer’s solution and 1ml /kg/hr of 5% Glucose. A huge difference in salt and water load resulted, and yet the results are reported as though we are comparing apples with apples.2
Finally, and arguably pertinent to the notion that there is extraordinary variation in fluid administration practices, there are increasing reports of the rare but disastrous adverse outcome of unexpected blindness following spine surgery.4,5 In several articles published in the winter issue of the 2013 APSF Newsletter, excessive crystalloid administration, coupled with a relative under-utilization of colloid, was highlighted as a possible causative factor.4 One case-control study identified high crystalloid and low colloid volume administration as a risk factor for developing postoperative visual loss from ischemic optic neuropathy after major spine surgery.5
So why does this conundrum continue? The plea for a more measured approach to fluid management echoes down the decades. The late Tom Shires (former professor and chairman of Surgery, Southwestern Medical School, Dallas) is credited with being an early advocate for the need to fill the “third space.”6 Those of us who trained in the last century learned of the mysterious “third space.” a secret place lurking deep within the human body that, under certain circumstances, would consume intravenous fluid with an almost insatiable appetite: the physiological equivalent of a black hole. General wisdom, repeated in our textbooks, was that a patient with an open belly needed at least 20 ml/kg/hr just to satisfy the “third space.”6 Liberal fluid administration was the fashion and liter upon liter of salt rich solutions were commonly poured into our patients. Edema was inevitable. The iatrogenic “Michelin Man,” eyes closed with peri-orbital edema, was routinely delivered to critical care units around the world. “Don’t worry—it does not harm—it’s just aesthetic.” “The beans (kidneys) will handle it.” “Nothing a few slugs of furosemide won’t fix.” These sounds and visions will be all too familiar to many readers. In 1967, Shires and Francis Moore (former professor and surgeon-in-chief, Harvard Medical School, Boston) wrote an article entitled “Moderation” in which they stated:7 “Salt solutions were undesirable during and after the operative period, unless there was external loss or traumatic edema. . . . The recommendation has been made by some that salt solutions should be used to ‘fill’ the vascular volume and then ‘maintain’ it by flooding the interstitial fluid volume. These advocates also advanced the idea that patients should be given four times the anticipated blood loss before it occurs. . . . The tendency of physicians and surgeons to go all out for new ideas, is noteworthy…. But it should be tempered with caution in adopting simple rules of thumb that prevent accuracy in estimates and replacement. . . . Instead of any such rule of thumb, the surgeon should carry on with his established habits of careful assessment of the patient’s situation, the losses incurred, and the physiologic needs in replacement. The objective of care is restoration to normal physiology and normal function of organs, with a normal blood volume, functional body water, and electrolytes. This can never be accomplished by inundation.”7
Nearly 50 years since this plea went out, the current observational cohort data suggest that inundation persists as a commonly deployed therapeutic approach and has been joined by a new fashion—that of desiccation (or fluid restriction). A number of studies have explored the impact of so-called “fluid restriction.” Perhaps most notably in recent years, Brandstrup et al. demonstrated that “restriction” of peri-operative fluid volumes resulted in better outcomes in a multi-center European randomized clinical trial.8Subsequent studies and meta-analyses have reinforced this view. It is not unusual in Enhanced Recovery after Surgery (ERAS) to find the term “intraoperative fluid restriction.”9 However, more detailed examination of the literature and more recent scholarly reviews offer alternate language: “zero balance” or the avoidance of salt and water excess.2,10 The advocates of “restriction” were responding to a world of inundation and wished for moderation. The intent was not to advocate actual restriction, just a brake on liberal or excessive administration of salt solutions. However, as Moore and Shires pointed out 50 years ago,7 many of us are dedicated followers of fashion, and have a tendency to go all out for the new thing, in this case fluid restriction. Sadly, it looks like the new thing is another “rule of thumb that may prevent accuracy in estimates and replacement” and may similarly be causing harm.3,7
So why not just give the right amount of fluid guided by “careful assessment of the patient’s situation, the losses incurred, and the physiologic needs in replacement”?7 This is the mantra of the “optimisers” or “goal directors.”2,3,10-13 Why not use physiological measurements including advanced cardiac output monitoring to guide fluid therapy? Why not reduce the background “maintenance” infusion of balanced crystalloid to a much lower level, consistent with the true estimates of requirements available from modern scientific studies (approximately 1–3 ml/kg/hr) and only give additional boluses of fluid to match need judged by measured volumes lost and changes in hemodynamic variables.11-15 On balance, the literature suggests that any algorithm-based perioperative fluid regimen results in improved patient outcomes, and the largest published randomized clinical trial demonstrates that lower volumes of fluid are administered in the intervention group, supporting the notion of “Goal-Directed Fluid Restriction.”10-11
International audits of perioperative fluid management suggest that the availability of institutional guidelines, algorithms, audits, and the application of goal directed fluid management guided by flow monitors is rare.12-14 Clinical experience, blood pressure, central venous pressure, and urine output are the most commonly used guides.12 When surveyed about poor adoption of “Goal Directed Therapy,” there are 3 recurring themes that emerge (in rank order): lack of availability of monitoring tools, lack of experience with instruments, and no perceived benefit.14 Regarding the evidence of perceived benefit, a recent meta-analysis concludes that there is no evidence of harm and clear evidence of benefit in terms of reduced complications and length of stay.11 However, there is still a lack of definitive evidence from large, high-quality, multicenter trials with patient centered outcomes. International teams are trying to address this.10,16 However, absolute clarity is unlikely as fluid management is a highly complex intervention that is changing year by year. If we get a definitive result for elective open intra-abdominal surgery, then what about laparoscopic, or robotic, or emergency surgery, and so on with no end of questions in sight. In the interim, we should accept that perioperative fluid management is a major patient safety issue and do something pragmatic to reduce iatrogenic patient harm.
If we accept that the status quo is sub-optimal and may be causing significant patient harm, then what can we, as a community, do now? When surveyed, the vast majority (86.5%) of ASA respondents and 98.1% of ESA respondents felt that their current hemodynamic management could be improved.14 Consensus statements have been published from a broad range of constituencies and all agree on the big message being the avoidance of fluid underload and overload.2,12 However, this important signal seems lost in the noise of very public arguments over relatively “small-print” issues such as colloid or crystalloid, Ringers Lactate or Saline, monitor A or monitor B. This notion partially drove the impetus for the development of the Cheers-Dream campaign in May 2015 at the first American Society of Enhanced Recovery meeting in Washington, DC.17Started by a group of perioperative fluid management enthusiasts frustrated by decades of lack of progress, the Cheers-Dream campaign concentrates on broad principles and objectives. The Cheers-Dream campaign is completely technology-agnostic and has no industry sponsorship. The aim of the campaign is quality improvement based on simple objectives, a patient centered outcome (the “DrEaM”), audit cycles, and ongoing education, and sharing of best practices. In other words, find out where you are, try to get to a better place and, if you get to a better place, please let others know how to get there.
In conclusion, current (chaotic) fluid administration is causing harm at the extreme of excess and inadequate fluid. Each of us can only know that we are not part of the problem if we engage in Quality Improvement on an on-going basis and can demonstrate consistency of practice and lack of harm (i.e., audit our fluid administration practice and outcomes). The Cheers-Dream campaign offers a clearly defined, easily measurable, and self-evidently patient relevant outcome variable for lack of harm, against which to compare your process variables (how much fluid). If you can do this without a system, then great; if not, then please get a system that works for you—choose from the menu of options and get on and do it. So, cheers to the dream of moderation.
- Lilot M, Ehrenfeld JM, Lee C, Harrington B, Cannesson M, Rinehart J. Variability in practice and factors predictive of total crystalloid administration during abdominal surgery: retrospective two-centre analysis.Br J Anaesth2015;114:767–76.
- Minto G, Mythen MG. Perioperative fluid management: science, art or random chaos?Br J Anaesth 2015;114:717–21.
- Thacker JK, Mountford WK, Ernst FR, Krukas MR, Mythen MM. Perioperative fluid utilization variability and association with outcomes: considerations for enhanced recovery efforts in sample US surgical populations.Ann Surg2016;263:502–510.
- Lee LA, Stoelting RK. APSF-Sponsored conference on perioperative visual loss develops consensus.APSF Newsletter 2013;27:52–53.
- Postoperative Visual Loss Study Group. Risk factors associated with ischemic optic neuropathy after spinal fusion surgery.Anesthesiology 2012;116:15–24.
- Shires T, Williams J, Brown F. Acute change in extracellular fluids associated with major surgical procedures.Ann Surg 1961; 154: 803-10.
- Moore FD, Shires G. Moderation.Ann Surg 1967;166: 300–1.
- Brandstrup B, Tønnesen H, Beier-Holgersen R, et al. Danish Study Group on Perioperative Fluid Therapy. Effects of intravenous fluid restriction on postoperative complications: comparison of two perioperative fluid regimens: a randomized assessor-blinded multicenter trial.Ann Surg 2003; 238:641–8.
- Aarts MA, Okrainec A, Glicksman A, Pearsall E, Victor JC, McLeod RS. Adoption of enhanced recovery after surgery (ERAS) strategies for colorectal surgery at academic teaching hospitals and impact on total length of hospital stay.Surg Endosc 2012; 26: 442-50.
- Miller TE, Roche AM, Mythen M. Fluid management and goal-directed therapy as an adjunct to Enhanced Recovery After Surgery (ERAS).Can J Anaesth2015;62:158–68.
- Pearse RM, Harrison DA, MacDonald N, et al. OPTIMISE Study Group. Effect of a perioperative, cardiac output-guided hemodynamic therapy algorithm on outcomes following major gastrointestinal surgery: a randomized clinical trial and systematic review.JAMA 2014;311:2181–90.
- Navarro LH, Bloomstone JA, Auler JO Jr, et al. Perioperative fluid therapy: a statement from the international Fluid Optimization Group.Perioper Med (Lond)2015;4:3.
- Ahmad T, Beilstein CM, Aldecoa C, et al. Variation in haemodynamic monitoring for major surgery in European nations: secondary analysis of the EuSOS dataset.Perioper Med (Lond) 2015;4:8.
- Cannesson M, Pestel G, Ricks C, Hoeft A, Perel A. Hemodynamic monitoring and management in patients undergoing high risk surgery: a survey among North American and European anesthesiologists.Crit Care 2011;15:R197.
- Goal-directed fluid therapy- a survey of anaesthetists in the UK, USA, Australia and New Zealand. Srinivasa S, Kahokehr A, Soop M, Taylor M, Hill AG.BMC Anesthesiol 2013;22;13:5.
- REstrictive Versus LIbEral Fluid Therapy in Major Abdominal Surgery: RELIEF Study. http://www.relief.org.au.
- Cheers Dream (no date). Available Online: http://www.cheers-dream.com.
Michael (Monty) G Mythen
Dr. Mythen is Smiths Medical Professor of Anaesthesia and Critical Care at University College London, UK.
Expert advisor for NICE Guidance.
Co-author GIFTASUP guidelines.
National Clinical Lead and Advisor Enhanced Recovery Partnership UK Dept Health May 2009-March 2013.
Consultant for Edwards Lifesciences and Deltex Medical.
Advisory Board Bev MD (proceeds to charity).
Co-Inventor‘QUENCH’ (Pat pending).
Editor-in-Chief Perioperative Medicine.
Editorial Board BJA.
Council Member Royal College of Anaesthetists.
Chair, DMEC for RELIEF trial.
Founding supporter Cheers-Dream Campaign.
Chair Advisory Board of the American Society for Enhanced Recovery (ASER).
Co-Director Evidence Based Perioperative Medicine (EBPOM)
Michael P W Grocott
Dr. Grocott is Professor of Anaesthesia and Critical Care Medicine at University of Southampton, UK.
British Oxygen Company Professor of the Royal College of Anaesthetists (2011-2015)
Director of the National Institute of Academic Anaesthesia Health Services Research Centre (2011-2016).
Council Member, Royal College of Anaesthetists. Board Member
Faculty of Intensive Care Medicine. Board Member, UK Enhanced Recovery After Surgery Society (ERAS-UK).
Member, Advisory Board of the American Society for Enhanced Recovery (ASER).
Co-Director Evidence Based Perioperative Medicine (EBPOM)