Why are patients with cirrhosis and upper gastrointestinal bleed routinely treated with antibiotics?

Cirrhotic patients with upper gastrointestinal bleed (UGIB) are at high risk of bacterial infections: 22% during the first 48 h after admission, 35-66% within 2 weeks of initial bleeding1. Antibiotic prophylaxis has been shown to reduce short term mortality, bacterial infections, early rebleeding and volume of blood transfused1-4.

But what is the exact connection between UGIB and bacterial infections in cirrhosis? One hypothesis is that UGIB sets up the host for bacterial infection via translocation (eg, due to hypovolemia), procedures necessary in the management of bleeding (eg endoscopy, sclerotherapy, IV access), and aspiration pneumonia. More intriguing is the reverse hypothesis—that is the bacterial infection serves as a trigger for UGIB.  Several lines of evidence support this view1,2.

  • Cirrhotic patients admitted for non-UGIB-related conditions may be 4x more likely to develop UGIB during their hospitalization in the presence of bacterial infection on admission4
  • Infections predispose to early variceal rebleeding
  • Infection/endotoxemia increase portal pressure, and impair liver function and coagulation
  • Commonly cited risk factors for variceal bleeding (eg, hepatic venous pressure gradient, liver function, size of varices) do not readily explain why bleeding occurs unpredictably and why despite daily increases in portal pressure (eg, following daily meals and exercises), UGIB is relatively infrequent.

 

References

  1. Thalheimer U, Triantos CK, Samonakis DN, et al. Infection, coagulation, and variceal bleeding in cirrhosis. Gut 2005;54:556-63. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1774431
  2. Goulis J. Bacterial infection in the pathogenesis of variceal bleeding. Is there any role for antibiotic prophylaxis in the cirrhotic patient. Ann Gastroenterol 2001;14:205-11. http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&ved=0ahUKEwjNh-rhlpLVAhXGdD4KHSurANcQFgg4MAM&url=http%3A%2F%2Fwww.annalsgastro.gr%2Findex.php%2Fannalsgastro%2Farticle%2Fdownload%2F80%2F71&usg=AFQjCNHJfAyYAjuNXpwsWGrVuyuxxgJYKg
  3. Soares-Weiser K, Brezis, Tur-Kaspa R, et al. Antibiotic prophylaxis of bacterial infections in cirrhotic inpatients: a meta-analysis of randomized controlled trials. Scand J Gastroenterol 2003;38:193-200. http://www.tandfonline.com/doi/abs/10.1080/00365520310000690
  4. Anastasioua J, Williams R. When to use antibiotics in the cirrhotic patient? The evidence base. Ann Gastroenterol. 2013; 26(2): 128–131. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3959942
  5. Benavides J, Fernandez N, Colombato L, et al. Further evidence linking bacterial infection and upper G.I. bleeding in cirrhosis. Results from a large multicentric prospective survey in Argentina. J Hepatol 2003;38 (suppl 2):A176. http://www.journal-of-hepatology.eu/article/S0168-8278(03)80592-5/abstract
Why are patients with cirrhosis and upper gastrointestinal bleed routinely treated with antibiotics?

Should I use a hemoglobin level of 7 or 8 g/dL as a threshold for blood transfusion in my hospitalized patient?

Unlike its previous 2012 guidelines that recommended overlapping hemoglobin level triggers of 7 g/dL to 8 g/dL for most inpatients, the 2016 guidelines from AABB (formerly known as the American Association of Blood Banks) assigns 2 distinct tiers of hemoglobin transfusion triggers: 7 g/DL for hemodynamically stable adults, including those in intensive care units, and 8 g/dL for patients undergoing cardiac or orthopedic surgery or with preexisting cardiovascular disease1 , often defined as history of coronary artery disease, angina, myocardial infarction, stroke, congestive heart failure, or peripheral vascular disease2,3.  

These recommendations are based on an analysis of over 30 randomized trials, taking into account the potential risks of withholding transfusions, including 30-day mortality, and myocardial infarction. The new 2-tier recommendation specifically excludes those with acute coronary syndrome, severe thrombocytopenia (patients treated for hematological or oncological reasons who are at risk of bleeding), and chronic transfusion-dependent anemia.

The guidelines also emphasize that good clinical practice dictates considering not only the hemoglobin level but the overall clinical context when considering blood transfusion in patients. These factors include alternative therapies to transfusion, rate of decline in hemoglobin level, intravascular volume status, dyspnea, exercise tolerance, light-headedness, chest pain considered of cardiac origin, hypotension, tachycardia unresponsive to fluid challenge, and patient preferences. In addition, standard practice should be to initiate a transfusion with 1 unit of blood rather than 2 units1.

 

References

  1. Carson JL, Guyatt G, Heddle NW. Clinical practice guidelines from the AABB red blood cell transfusion thresholds and storage. JAMA. Doi:10.1001/jama.2016.9185. Published online October 12, 2016.
  2. Carson JL, Duff A, Poses RM, et al. Effect of anemia and cardiovascular disease on surgical mortality and morbidity. Lancet 1996;348:1055-60.
  3. Carson JL, Siever F, Cook DR, et al. Liberal versus restrictive blood transfusion strategy: 3-year survial and cause of death results from the FOCUS randomized controlled trial. Lancet 2015;385:1183-1189.
Should I use a hemoglobin level of 7 or 8 g/dL as a threshold for blood transfusion in my hospitalized patient?