The ultimate showdown between Normal Saline and Lactated Ringers. (Oh hey albumin, didn’t see you over there.)
The battle over the superiority of resuscitation fluids is coming to a boil. Enter the Fluid Wars. Are Lactated Ringers superior to normal saline? Will LR increase a patient’s lactate? What about albumin? The Curbsiders quench the thirst for knowledge by turning to masters Dr. Pascale Khairallah (@Khairallah_P), Dr. Charlie Wray (@WrayCharles) and Dr. Joel Topf (@kidney_boy) for guidance in this special @NephMadness episode that will get your feet wet with the complicated world of fluid resuscitation.
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Written and produced by: Justin Berk, MD, Pascale Khairallah MD
NephMadness Pun Contest produced by: Hannah R Abrams MS3
Hosts: Matthew Watto MD, Paul Williams MD, Stuart Brigham MD
Edited by: Matthew Watto, MD
Guest: Pascale Khairallah MD, Charlie Wray DO, Joel Topf MD
00:00 Nephmadness pun contest
02:52 Intro to the show and NephMadness, guest bios
08:04 Guest one-liners,
10:58 Joel explains NephMadness
12:58 Guest book recommendations and career advice
17:30 Clinical case; goals of fluid resuscitation; choice of initial IV fluid
Corporate (TV series) Comedy Central
19:41 Complications of normal saline
21:29 Colloids versus crystalloids
LR versus normal saline is not an innocuous decision
26:32 Saline versus balance fluids. What’s the makeup?
28:19 Does lactated ringers elevate lactate?
31:03 Is hyperkalemia a contraindication for LR?
32:39 Lactated ringers versus plasma-lyte and cost of fluid
34:49 In vitro risks of normal saline
40:31 SMART and SALT-ED trial
46:08 Stuart finds the IV fluid price list
44:37 Each panelist weighs in on saline versus balanced fluids
46:45 Why do patients with metabolic alkalosis thrive on saline?
Fluid Wars Pearls
Colloids and crystalloids are probably equally efficacious for fluid resuscitation.
Colloids are more expensive and may cause more brain injury in trauma patients.
Recent data shows Lactated Ringers (LR) may be superior to Normal Saline (NS) for fluid resuscitation based on SALT-ED and SMART trial data (less MAKE30 aka major adverse kidney events in 30 days).
The lactate in lactated ringers is benign (sodium lactate, NOT lactic acid). Checking a lactate for tissue perfusion is a proxy for lactic acidosis. The acidosis is the concern, not the lactate itself.
Patients with cirrhosis cannot metabolize lactate quickly. Thus, LR may cause a benign increase in lactate even if there is good tissue perfusion.
Normal Saline may be indicated in specific situations such as metabolic alkalosis.
Crystalloid: “Electrolytes mixed with water.” This can include Normal Saline or “Balanced Fluids.”
Normal Saline:Salt and Water: 0.9% Saline = 9g Sodium and Chloride in 1L of water.
Balanced Fluids: Solutions that contain more electrolytes to better simulate plasma; they contain potassium, calcium, magnesium, and buffer (e.g. lactate, acetate). Examples include Lactated Ringers, PlasmaLyte, Hartmann’s solution.
Colloid: Colloid fluids contain a greater osmolar load including albumin, Hetastarch (synthetic albumin), or blood products.
Fluid Resuscitation: LR vs. NS
Goal of Fluid Resuscitation
The goal of resuscitation is to replenish bodily fluid that has been lost and restore tissue perfusion.
Tissue perfusion can be measured through several ways
The decision seems to be benign as any complication is relatively rare. (@kidney_boy expert opinion)
A large (7,000 patients) follow-up study (SAFE trial) in 2004, showed NO change in mortality between albumin and crystalloid. However, in sub-group analysis:
Trauma patients (and traumatic brain injuries) had increased risk of death and associated brain injury with albumin use in the SAFE trial.
Septic patients showed possible benefit with albumin in the SAFE trial. BUT, a follow-up study for albumin in sepsis (ALBIOS Trial) showed albumin was confirmed to NOT be associated with improved mortality in septic patients
Cochrane Review of colloids
A Cochrane review states: “using colloids…for fluid replacement probably makes little or no difference to the number of critically ill people who die.”
Colloid remains more expensive despite lack of advantage
Hyperchloremia: The macula densa (in distal tubule) senses chloride (elevated chloride concentration in NS solution) → stimulates release of vasoconstrictors → constriction of afferent arteriole → decrease glomerular filtration rate → acute kidney injury. Check out this Image from PulmCrit article.
Thromboxane and angiontension released in response which also worsens vasoconstriction.
Maculadensa: If it detects increased chloride it suggests a failure of electrolyte reabsorption and the solution to this issue: it will shut down the glomeruli.
Addressing Concerns with Lactated Ringers
Will Lactate Ringers elevated the lactate level in critically ill patients?
In patients with sepsis, anaerobic glycolysis will cause an increase of lactic acid.
Lactic acid = Lactate plus a Hydrogen Ion.
The hydrogen ion causes all the complications (ie the acidosis). The lactate is just the accompanying ion and is benign. Lactated ringers is Sodium Lactate and does not not contain the H+.
Kashlak Pearl: Patients with cirrhosis cannot convert lactate quickly (60% of lactate metabolism is in the liver). Thus, Lactate may go up in patients with liver disease receiving LR. BUT, this is not a sign of poor tissue perfusion. It simply reflects the slow metabolism of the benign lactate in LR. In summary, patients with a sick liver receiving LR might have a benign lactate elevation. This is not the same as lactic acidosis.
Specific Indications of Normal Saline
Metabolic alkalosis (e.g. after significant vomiting or overdiuresis):
These patients need chloride.
Chloride depletion is driving the metabolic alkalosis.
Give Normal Saline (or potassium chloride) to correct metabolic alkalosis.
Is Hyperkalemia a contraindication to LR?
Why give more K to a patient with elevated potassium?
A couple of studies suggest that the metabolic acidosis from NS causes an transcellular shift. Thus, More hyperkalemia with NS than balanced solutions. Though beware: these studies only performed in kidney transplant patients.
See discussion at NephMadness. (And learn more about Hyperkalemia from a previous episode).