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Table of Contents
EDITORIAL
Year : 2017  |  Volume : 33  |  Issue : 2  |  Page : 148-150

Thoracic epidural block in sepsis: Looking beyond the known


Department of Anaesthesiology and Critical Care, University College of Medical Sciences and GTB Hospital, Delhi, India

Date of Web Publication7-Jul-2017

Correspondence Address:
Asha Tyagi
103, Siddhartha Enclave, New Delhi - 110 014
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/joacp.JOACP_121_17

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How to cite this article:
Tyagi A. Thoracic epidural block in sepsis: Looking beyond the known. J Anaesthesiol Clin Pharmacol 2017;33:148-50

How to cite this URL:
Tyagi A. Thoracic epidural block in sepsis: Looking beyond the known. J Anaesthesiol Clin Pharmacol [serial online] 2017 [cited 2017 Jul 20];33:148-50. Available from: http://www.joacp.org/text.asp?2017/33/2/148/209734

Thoracic epidural block (TEB) is a commonly used anesthetic technique, indicated for its well-established analgesic as well as nonanalgesic effects.[1] Previously documented nonanalgesic benefits include enhanced gastrointestinal motility that in turn reduces the duration of hospital stay and hence the hospital cost, reduced intraoperative blood loss, and an attenuated perioperative stress response.

The use of TEB in patients with sepsis has traditionally been considered a relative contraindication.[2] There is evidence however, to suggest that TEB may indeed have a beneficial role during sepsis, offering a new paradigm for its application.[3]

It is well established that sepsis is characterized by splanchnic hypoperfusion and redistribution of blood flow away from the mucosa of gut. This leads to disruption of mucosal barrier and consequent translocation of bacteria across the gut wall, heralding sepsis.[3] TEB results in a sympathetic blockade, and if this extends to the neural supply of splanchnic circulation intestinal blood flow may increase thus attenuating sepsis.

To extend this hypothesized benefit of TEB during sepsis, evidence should convince us of two individual effects. First, that TEB increases splanchnic blood flow, and second that it improves outcome in patients with sepsis.

Regarding the first effect, that TEB can indeed augment the splanchnic blood flow is well documented in aseptic experimental models,[4],[5] aseptic patients undergoing abdominal surgery,[6],[7],[8] and experimental septic models as well.[9],[10],[11] Herein, the augmentation in splanchnic blood flow by TEB was documented using various methods such as intravital microscopy,[4],[5],[10],[11] laser Doppler flowmetry,[8] fluorescent microsphere reference withdrawal technique [9] and intramucosal pH.[6],[7]

Besides an increase in splanchnic circulation, there are suggestions of other mechanisms by which TEB may benefit during sepsis. TEB was also seen to produce advantageous effects in experimental models of adverse pathophysiological situations that simulate changes of a septic state.[12],[13] Herein, in an experimental model of mesenteric ischemia, TEB attenuated the systemic inflammatory response and intestinal damage evidenced by levels of antioxidants, superoxide dismutase, glutathione peroxidase, myeloperoxidase, malondialdehyde, intracellular adhesion molecule-1, etc.[13] In another experimental model of hypoxic hypoxia, use of TEB prevented gut injury and subsequent translocation of endotoxin.[12]

Based on the above discussion, there is thus substantial evidence to suggest the potential for the benefit of TEB in attenuating the progression of sepsis.

However, when it comes to evidence of the second effect of TEB during sepsis, namely, improved outcome in septic patients, there is a relative paucity of literature. The clinical application of TEB for exploiting the suggested benefits in sepsis is perhaps limited by a fear of infective complications and hemodynamic perturbations.

Only three published clinical studies dealing with the potential benefits of TEB in patients with sepsis could be located.[14],[15],[16] The earliest was conducted by Spackman et al.[14] in critically ill patients with peritonitis and adynamic bowel following abdominal surgery. In their double-blinded, randomized, and controlled study, the effect of TEB versus intravenous morphine was assessed on gastric perfusion and motility evidenced by gastric tonometry and abdominal ultrasound, in addition to paracetamol absorption. The gastric perfusion was found to be significantly better with the use of the epidural, the intramucosal pH being significantly higher and mucosal: arterial PCO2 gradient being lower in patients with the blockade (P = 0.024). Significant improvements were seen in the ultrasound appearance of the small bowel as well (P = 0.004). It was concluded that the epidural analgesia resulted in improvements in gastric mucosal perfusion and ultrasound appearance of the small bowel, indicating its potential clinical benefit in a patient population in which it is traditionally contraindicated! Another randomized clinical trial [15] evaluated whether combining TEB along with general anesthesia could decrease the sepsis-related postoperative mortality and morbidity. This randomized controlled study included adult patients undergoing emergency laparotomy for small intestinal perforation peritonitis-induced sepsis. The use of perioperative TEB decreased the postoperative mortality and major systemic morbidity, though the improvements were statistically insignificant. There was a significantly earlier return of bowel motility and earlier discharge from the hospital. Recently, a trial extended the previous work of evaluating the role of TEB in patients with perforation peritonitis undergoing abdominal laparotomy further.[16] Herein, systemic inflammatory markers of sepsis were also evaluated in addition to clinical outcome predictors. The inflammatory markers included interleukin (IL)-6, IL-10, procalcitonin, and C-reactive protein. TEB was associated with a statistically insignificant trend of preservation of anti-inflammatory response (higher IL-10) and lack of alteration of pro-inflammatory reaction (IL-6 levels), along with appreciably lower procalcitonin, and decreased the incidence of raised C-reactive protein. The postoperative sepsis-related organ failure assessment score was also clinically lower with the use of the epidural. The postoperative return of bowel motility was significantly faster.

These clinical studies thus suggest trends of improvement in sepsis-related morbidity, mortality, and inflammatory markers. To conclusively prove the statistical significance of these results, further much larger trials would be required in this hitherto unexplored area.

In this context, it is also relevant to note that in clinical practice it is common to encounter usage of an epidural during “high-risk” laparotomies in patients including those with perforation peritonitis. The reasons however mostly involve analgesia or sparing of anesthetics intraoperatively, or enhanced postoperative bowel motility.

The two primary concerns with the use of thoracic epidural in septic patients, hemodynamic instability, and infective neurological complications also need to be addressed.

It can be hypothesized that hemodynamic instability following the blockade is worse than in an aseptic patient, and hence, the proposed advantage of augmenting gastrointestinal blood flow could be lost. There is some evidence to lay these apprehensions to rest. The use of vasopressor infusion was seen to be similar with or without thoracic epidural in septic patients.[15],[16] The hemodynamic stability after the block was maintained using fluids and ephedrine boluses as done in routine practice.[16] Studies on endotoxemic animal models have also shown that there is no impairment of hemodynamics following segmental TEB with 0.1% bupivacaine beyond the changes caused by sepsis per se.[17],[18] Of course, maintenance of blood pressure after the epidural block using fluids and vasopressor boluses must continue to be a clinical goal as in the routine application of the technique. Regarding the apprehension of infective neurological complications when employing the block in septic patients, its rarity (<1%) requires a very large sized clinical trial to address the issue conclusively. None of the clinical trials, however, evaluating TEB in patients with sepsis have observed infective neuraxial complication.[15],[16],[17] Avoiding long duration of catheterization, use of antibiotics and the removal of the infective focus were cited as probable protective influence against the infective complications.

The patients with sepsis wherein the benefits of TEB on the progression of the disease could be thought about are likely to be a limited subset of septic patients. Preexisting hemodynamic instability and coagulopathy being absolute contraindications to neuraxial block would exclude those with the advanced and severe disease. Furthermore, it needs to be emphasized that the potential benefits of TEB in increasing splanchnic circulation and thus the progression of sepsis, will be applicable only if the sympathetic block extends from T5 to T10,[3] keeping in mind its neural innervation. Lumbar epidural cannot replace the segmental TEB under these circumstances since it would rather offset the benefits, by the unrestricted larger dermatomal spread leading to extensive vasodilation and fall in splanchnic perfusion.[3]

Thus, although epidural catheterization is traditionally avoided in patients with sepsis for fear of infectious complications and lack of any specific benefit, recent animal and clinical data force reconsideration of the latter belief. There has been increasing interest in the use of TEB in sepsis and critically ill patients. Not only is there evidence that TEB increases the gastrointestinal blood flow in sepsis, thus preventing splanchnic ischemia, it may also benefit by attenuating ischemia- or infection-related inflammatory responses originating from splanchnic region by other mechanisms.

Sepsis has continued to be a leading killer, and there are very few interventions such as antibiotic therapy that can actually alter the outcome. This encourages the search for newer interventions or application of known ones beyond their previously established effects. This definitely leaves room for further research and clinical application of using TEB in patients with “sepsis,” with utmost care.

 
  References Top

1.
Freise H, Van Aken HK. Risks and benefits of thoracic epidural anaesthesia. Br J Anaesth 2011;107:859-68.  Back to cited text no. 1
[PUBMED]    
2.
Brown DL. Spinal, epidural, and caudal anesthesia. In: Miller RD, Eriksson LI, Fleisher LA, Wiener-Kronish JP, Young WL, editors. Miller's Anesthesia. 7th ed. Philadelphia: Churchill Livingstone; 2010. p. 1611-35.  Back to cited text no. 2
    
3.
Sielenkämper AW, Van Aken H. Thoracic epidural anesthesia: More than just anesthesia/analgesia. Anesthesiology 2003;99:523-5.  Back to cited text no. 3
    
4.
Sielenkämper AW, Eicker K, Van Aken H. Thoracic epidural anesthesia increases mucosal perfusion in ileum of rats. Anesthesiology 2000;93:844-51.  Back to cited text no. 4
    
5.
Adolphs J, Schmidt DK, Mousa SA, Kamin B, Korsukewitz I, Habazettl H, et al. Thoracic epidural anesthesia attenuates hemorrhage-induced impairment of intestinal perfusion in rats. Anesthesiology 2003;99:685-92.  Back to cited text no. 5
    
6.
Kapral S, Gollmann G, Bachmann D, Prohaska B, Likar R, Jandrasits O, et al. The effects of thoracic epidural anesthesia on intraoperative visceral perfusion and metabolism. Anesth Analg 1999;88:402-6.  Back to cited text no. 6
    
7.
Sutcliffe NP, Mostafa SM, Gannon J, Harper SJ. The effect of epidural blockade on gastric intramucosal pH in the peri-operative period. Anaesthesia 1996;51:37-40.  Back to cited text no. 7
    
8.
Johansson K, Ahn H, Lindhagen J, Tryselius U. Effect of epidural anaesthesia on intestinal blood flow. Br J Surg 1988;75:73-6.  Back to cited text no. 8
    
9.
Schäper J, Ahmed R, Perschel FH, Schäfer M, Habazettl H, Welte M. Thoracic epidural anesthesia attenuates endotoxin-induced impairment of gastrointestinal organ perfusion. Anesthesiology 2010;113:126-33.  Back to cited text no. 9
    
10.
Daudel F, Freise H, Westphal M, Stubbe HD, Lauer S, Bone HG, et al. Continuous thoracic epidural anesthesia improves gut mucosal microcirculation in rats with sepsis. Shock 2007;28:610-4.  Back to cited text no. 10
    
11.
Adolphs J, Schmidt DK, Korsukewitz I, Kamin B, Habazettl H, Schäfer M, et al. Effects of thoracic epidural anaesthesia on intestinal microvascular perfusion in a rodent model of normotensive endotoxaemia. Intensive Care Med 2004;30:2094-101.  Back to cited text no. 11
    
12.
Ai K, Kotake Y, Satoh T, Serita R, Takeda J, Morisaki H. Epidural anesthesia retards intestinal acidosis and reduces portal vein endotoxin concentrations during progressive hypoxia in rabbits. Anesthesiology 2001;94:263-9.  Back to cited text no. 12
    
13.
Bedirli N, Akyürek N, Kurtipek O, Kavutcu M, Kartal S, Bayraktar AC. Thoracic epidural bupivacaine attenuates inflammatory response, intestinal lipid peroxidation, oxidative injury, and mucosal apoptosis induced by mesenteric ischemia/reperfusion. Anesth Analg 2011;113:1226-32.  Back to cited text no. 13
    
14.
Spackman DR, McLeod AD, Prineas SN, Leach RM, Reynolds F. Effect of epidural blockade on indicators of splanchnic perfusion and gut function in critically ill patients with peritonitis: A randomised comparison of epidural bupivacaine with systemic morphine. Intensive Care Med 2000;26:1638-45.  Back to cited text no. 14
    
15.
Tyagi A, Seelan S, Sethi AK, Mohta M. Role of thoracic epidural block in improving post-operative outcome for septic patients: A preliminary report. Eur J Anaesthesiol 2011;28:291-7.  Back to cited text no. 15
    
16.
Tyagi A, Bansal A, Das S, Sethi AK, Kakkar A. Effect of thoracic epidural block on infection-induced inflammatory response: A randomized controlled trial. J Crit Care 2017;38:6-12.  Back to cited text no. 16
    
17.
Daudel F, Bone HG, Traber DL, Stubbe HD, Lettau M, Lange M, et al. Effects of thoracic epidural anesthesia on hemodynamics and global oxygen transport in ovine endotoxemia. Shock 2006;26:615-9.  Back to cited text no. 17
    
18.
Daudel F, Ertmer C, Stubbe HD, Lange M, Pulina R, Bone HG, et al. Hemodynamic effects of thoracic epidural analgesia in ovine hyperdynamic endotoxemia. Reg Anesth Pain Med 2007;32:311-6.  Back to cited text no. 18
    




 

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