Why might Lactated Ringer’s (LR) solution be preferred over normal saline (NS) for fluid resuscitation in acute pancreatitis?

Although the data is limited, fluid resuscitation with lactated Ringer’s (LR) solution in acute pancreatitis has been associated with lower risk of persistent systemic inflammatory response syndrome (SIRS) compared to normal saline (NS),  with an additional trend toward lower mortality.1-3

A 2018 meta-analysis of 3 randomized-controlled trials (RCTs) and 2 retrospective studies involving 428 patients found a significantly lower odds of developing SIRS at 24 hours (OR 0.38, CI 0.15-0.98).   Mortality was also lower in the LR group (OR 0.61, 95% CI 0.28-1.29), though it did not reach statistical significance. 1

A small 2011 RCT was the first to suggest the “protective” effect of LR in acute pancreatitis, reporting significant reduction in the prevalence of SIRS after 24 hours when compared to NS (84% vs 0%);  patients on LR also had a significantly lower C-reactive protein (CRP) (104 mg/L vs 51.4 mg/L) at 24 hours. 2   Significantly lower CRP levels were also reported at 48 and 72 hours when LR was compared to NS in another RCT in acute pancreatitis.3

As for potential mechanisms for the observed beneficial effects of LR on the pancreatic tissue in acute pancreatitis, hyperchloremic metabolic acidosis (with its attendant low extracellular pH) often seen in large volume NS resuscitation was initially thought to contribute to pancreatic injury.2  A more plausible explanation, however, may relate to the direct anti-inflammatory effect of lactate itself.  Of interest, lactate has been shown to inhibit macrophage induction invitro 4  and suppress innate immunity in experimental models of pancreatitis. 3 Who would have guessed!

Bonus Pearl: Did you know that Ringer’s solution gets its name from Sydney Ringer, a 19th century physician who demonstrated the importance of salts of sodium, potassium, calcium and chloride in precise proportions for cellular function?  LR solution was actually concocted in the 1930s by a St. Louis pediatrician, Alexis Hartmann, and was also known as the “Hartmann’s solution”. 4

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References

  1. Iqbal U, Anwar H, Scribani M. Ringer’s lactate versus normal saline in acute pancreatitis: A systematic review and meta-analysis. J Dig Dis 208;19:335-341. https://onlinelibrary.wiley.com/doi/epdf/10.1111/1751-2980.12606
  2. Wu BU, Hwang JQ, Gardner TH, et al. Clin Gastroenterol Hepatol 2011;9:710-17. https://www.cghjournal.org/article/S1542-3565(11)00454-X/abstract
  3. de-Madaria E, Herrera-Marante I, Gonzalez-Camacho V, et al. Fluid resuscitation with lactated Ringer’s solution vs normal saline in acute pancreatitis: A triple-blind, randomized, controlled trial. UEG J 2017;6:63-72. file:///C:/Users/manifa/OneDrive%20-%20Mercy%20Online/pancreatitis%20LR2spain.pdf
  4. Lee JA. Sydney Ringer (1834-1910) and Alexis Hartmann (1898-1964). Anaesthesia 1981;36:1115-21. https://associationofanaesthetists-publications.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2044.1981.tb08698.x

Disclosures: The listed questions and answers are solely the responsibility of the author and do not necessarily represent the official views of Mercy Hospital-St. Louis or its affiliate healthcare centers. Although every effort has been made to provide accurate information, the author is far from being perfect. The reader is urged to verify the content of the material with other sources as deemed appropriate and exercise clinical judgment in the interpretation and application of the information provided herein. No responsibility for an adverse outcome or guarantees for a favorable clinical result is assumed by the author. Thank you!

 

Why might Lactated Ringer’s (LR) solution be preferred over normal saline (NS) for fluid resuscitation in acute pancreatitis?

My hospitalized patient with sepsis has persistently elevated lactic acid despite volume resuscitation, source control, and adequate oxygenation. What could I be missing?

Although the causes of lactic acidosis are legion (eg, sepsis, tissue hypoperfusion, ischemic bowel, malignancy, medications, liver dysfunction), thiamine deficiency (TD) is an often-overlooked cause of persistently elevated serum lactic acid (LA) in critically ill hospitalized patients,1 reported in 20-70% of septic patients.2  Septic shock patients may be particularly at risk of TD because of increased mitochondrial oxidative stress, decreased nutritional intake and presence of comorbid conditions (eg,  alcoholism, persistent vomiting).3

Early recognition of TD in hospitalized patients may be particularly difficult because of the frequent absence of the “classic” signs and symptoms of Wernicke’s encephalopathy (eg, ataxia, cranial nerve palsies and confusion) and lack of readily available confirmatory laboratory tests.4

TD-related lactic acidosis should be suspected when an elevated LA persists despite adequate treatment of its putative cause(s) (4,5). Administration of IV thiamine in this setting may result in rapid clearance of LA.3-5

TD causes lactic acidosis type B which is due to the generation of excess LA, not impairment in tissue oxygenation, as is the case for lactic acidosis type A. Thiamine is an essential co-factor in aerobic metabolism, facilitating the conversion of pyruvate to acetyl-CoA which enters the citric acid (Krebs) cycle within the mitochondria. In TD, pyruvate does not undergo aerobic metabolism and is converted to LA instead, leading to lactic acidosis.

Bonus pearl: Did you know that because of its limited tissue storage, thiamine stores may be depleted within only 3 weeks of reduced oral intake!

References

  1. O’Donnell K. Lactic acidosis: a lesser known side effect of thiamine deficiency. Practical Gastroenterol March 2017:24.   https://www.practicalgastro.com/article/176921/Lactic-Acidosis-Lesser-Known-Side-Effect-of-Thiamine-Deficiency
  2. Marik PE. Thiamine: an essential component of the metabolic resuscitation protocol. Crit Care Med 2018;46:1869-70. https://journals.lww.com/ccmjournal/Fulltext/2018/11000/Thiamine___An_Essential_Component_of_the_Metabolic.23.aspx
  3. Woolum JA, Abner EL, Kelly A, et al. Effect of thiamine administration on lactate clearance and mortality in patients with septic shock. Crit Care Med 2018;46:1747-52. https://journals.lww.com/ccmjournal/Fulltext/2018/11000/Effect_of_Thiamine_Administration_on_Lactate.5.aspx
  4. Kourouni I, Pirrotta S, Mathew J, et al. Thiamine: an underutilized agent in refractory lactic acidosis. Chest 2016; 150:247A. https://journal.chestnet.org/article/S0012-3692(16)56459-9/pdf
  5. Shah S, Wald E. Type B lactic acidosis secondary to thiamine deficiency in a child with malignancy. Pediatrics 2015; 135:e221-e224. http://pediatrics.aappublications.org/content/135/1/e221

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My hospitalized patient with sepsis has persistently elevated lactic acid despite volume resuscitation, source control, and adequate oxygenation. What could I be missing?

In my critically ill patient with infection, is capillary refill time greater than 2 seconds indicative of septic shock?

The data on the performance of capillary refill time (CRT) in adults is quite limited and what’s available does not suggest that the commonly cited 2 seconds cutoff is useful in assessing peripheral perfusion in critically ill adults1,2.

For example, a large study involving 1000 healthy adults reported that 45% of participants had a CRT > 2 seconds3.  Age also affects CRT with its 95 percentile upper limits reaching 4.5 seconds among healthy adults >60 y old3

Among patients with septic shock, a baseline median CRT of 5 seconds has been reported.  Values <5.0 seconds within 6 hours of treatment of septic shock has also been highly associated with successful resuscitation even before normalization of lactate levels4.

For these reasons, if CRT is used as a measure of peripheral perfusion in critically ill adults, a cut off of 5 seconds, not 2 seconds, may be more appropriate. But just like many other diagnostic tests, CRT should never be interpreted in isolation from other clinical parameters. 

References

  1. Lima A, Bakker J. Clinical Assessment of peripheral circulation. Critical Care 2015:21: 226-31. https://www.ncbi.nlm.nih.gov/pubmed/25827585  
  2. Lewin J, Maconochie I. Capillary refill time in adults. Emerg Med J 2008;25:325-6. https://www.ncbi.nlm.nih.gov/pubmed/18499809
  3. Anderson B, Kelly AM, Kerr D, et al. Impact of patient and environmental factors on capillary refill time in adults. Am J Emerg Med 2008;26:62-65. https://www.ncbi.nlm.nih.gov/pubmed/18082783
  4. Hernandez G, Pedreros C, Veas E, et al. Evolution of peripheral vs metabolic perfusion parameters during septic shock resuscitation. A clinical-physiologic study. J Crit Care 2012;27:283-288.  https://www.ncbi.nlm.nih.gov/pubmed/21798706
In my critically ill patient with infection, is capillary refill time greater than 2 seconds indicative of septic shock?