Thoracic epidural anesthesia: Effects on splanchnic circulation and implications in Anesthesia and Intensive care

Abstract

AIM:To evaluate the currently available evidence on thoracic epidural anesthesia effects on splanchnic macro and microcirculation, in physiologic and pathologic conditions. METHODS:A PubMed search was conducted using the MeSH database. Anesthesia, Epidural was always the first MeSH heading and was combined by boolean operator AND with the following headings: Circulation, Splanchnic; Intestines; Pancreas and Pancreatitis; Liver Function Tests. EMBASE, Cochrane library, ClinicalTrials. gov and clinicaltrialsregister.eu were also searched using the same terms. RESULTS:Twenty-seven relevant studies and four ongoing trials were found. The data regarding the effects of epidural anesthesia on splanchnic perfusion are conflicting. The studies focusing on regional macro-hemodynamics in healthy animals and humans undergoing elective surgery, demonstrated no influence or worsening of regional perfusion in patients receiving thoracic epidural anesthesia (TEA). On the other hand most of the studies focusing on micro-hemodynamics, especially in pathologic low flow conditions, suggested that TEA could foster microcirculation. CONCLUSION:The available studies in this field are heterogeneous and the results conflicting, thus it is difficult to draw decisive conclusions. However there is increasing evidence deriving from animal studies, that thoracic epidural blockade could have an important role in modifying tissue microperfusion and protecting microcirculatory weak units from ischemic damage, regardless of the effects on macro-hemodynamics.

Thoracic epidural analgesia: a new approach for the treatment of acute pancreatitis?

“…Richards et al [ 6 ] published in 2013 a systemic review which could not establish the real impact of TEA on splanchnic perfusion. Siniscalchi et al [ 7 ] also stated that studies focusing on regional macrocirculation could not show an influence on, or even showed worsening of, regional perfusion when TEA was used. In contrast, studies focusing on microcirculation, especially in pathologic flow conditions such as the state induced by AP, suggested that TEA could improve microcirculation [ 7 ].…”

“…Siniscalchi et al [ 7 ] also stated that studies focusing on regional macrocirculation could not show an influence on, or even showed worsening of, regional perfusion when TEA was used. In contrast, studies focusing on microcirculation, especially in pathologic flow conditions such as the state induced by AP, suggested that TEA could improve microcirculation [ 7 ]. There is growing evidence that microcirculation plays a crucial role in AP, and no treatment except TEA has proven to play a role in this aspect.…”

“…Bupivacaine 0.4 % 20 μl/h Hemodynamic and biological parameters Arterial blood gases Laser Doppler flowmetry of pancreatic microcirculation Histopathological analysis - TEA induced a strong increase in pancreatic microcirculation compared with AP group - TEA reduced the severity of metabolic acidosis - Histopathological analysis showed that TEA reduced acinar cells, without reaching statistical evidence Three different groups Histological analysis Reproducibility of the procedure Lauer [ 24 ] 2007 Rats 21 Three groups: 1) AP [ 7 ] 2) AP + TEA [ 7 ] 3) Sham a + TEA [ 7 ] Catheter insertion in L3– L4, advanced to T6. Bupivacaine 0.5 % 15 μl/h In-vivo and in-vitro analysis Hemodynamic and biological parameters Arterial blood gases Receptor-independent vasoconstriction Receptor-dependent and independent vasoconstriction by angiotensin and bradykinin - AP group had more severe metabolic and lactate acidosis compared with rats benefitting from TEA - TEA induced a better arterial oxygenation and higher mean arterial pressure compared with AP - TEA induced a better hypoxic vasoconstriction response associated with a reduction of exhaled nitric oxide, showing less smooth muscle cell dysfunction compared with AP - TEA induced a better receptor sensitivity to angiotensin II and bradykinin compared with AP Three different groups In-vivo and in-vitro analysis Reproducibility of the procedure Freise [ 26 ] 2009 Rats 28 + 22 Four groups: 1) Sham a + NaCl [ 7 ] 2) Sham a + TEA (7 + 8) 3) AP + NaCl (7 + 7) 4) AP + TEA (7 + 7) Catheter insertion in L3– L4, advanced to T6. Bupivacaine 0.5 % 15 μl/h Hemodynamic and biological parameters Arterial blood gases Intravital microscopy for sinusoid perfusion and diameter FasL expression measures Histopathological analysis - TEA reduced overall apoptosis and hepatocyte apoptosis compared with AP - TEA prevented sinusoid vasoconstriction, but did not influence loss of sinusoids and sinusoidal perfusion compared with AP - TEA did not induce significant changes in hemodynamic parameters, FasL expression, and arterial blood gases Four different groups Blinded investigators and pathologist Large sample with 22 rats added for histopathological analysis and FasL measures Reproducibility of the procedure Freise [ 18 ] 2006 Rats 28 …”

“…Bupivacaine 0.5 % 15 μl/h In-vivo and in-vitro analysis Hemodynamic and biological parameters Arterial blood gases Receptor-independent vasoconstriction Receptor-dependent and independent vasoconstriction by angiotensin and bradykinin - AP group had more severe metabolic and lactate acidosis compared with rats benefitting from TEA - TEA induced a better arterial oxygenation and higher mean arterial pressure compared with AP - TEA induced a better hypoxic vasoconstriction response associated with a reduction of exhaled nitric oxide, showing less smooth muscle cell dysfunction compared with AP - TEA induced a better receptor sensitivity to angiotensin II and bradykinin compared with AP Three different groups In-vivo and in-vitro analysis Reproducibility of the procedure Freise [ 26 ] 2009 Rats 28 + 22 Four groups: 1) Sham a + NaCl [ 7 ] 2) Sham a + TEA (7 + 8) 3) AP + NaCl (7 + 7) 4) AP + TEA (7 + 7) Catheter insertion in L3– L4, advanced to T6. Bupivacaine 0.5 % 15 μl/h Hemodynamic and biological parameters Arterial blood gases Intravital microscopy for sinusoid perfusion and diameter FasL expression measures Histopathological analysis - TEA reduced overall apoptosis and hepatocyte apoptosis compared with AP - TEA prevented sinusoid vasoconstriction, but did not influence loss of sinusoids and sinusoidal perfusion compared with AP - TEA did not induce significant changes in hemodynamic parameters, FasL expression, and arterial blood gases Four different groups Blinded investigators and pathologist Large sample with 22 rats added for histopathological analysis and FasL measures Reproducibility of the procedure Freise [ 18 ] 2006 Rats 28 Four groups: 1) Sham a + NaCl [ 7 ] 2) AP + NaCl [ 7 ] 3) AP + TEA [ 7 ] 4) AP + TEA 7 hours after AP induction Catheter insertion in L3– L4, advanced to T6. Bupivacaine 0.5 % 15 μl/h Intravital microscopy of ileal mucosa Hemodynamic and biological parameters Arterial blood gases Histopathological analysis - TEA increased survival at 7 days from 33 to 73 % compared with AP group - TEA did not induce more hypotension compared with AP group - A reduction of 50 % of the ileal arteriolar perfusion was observed in the AP group, restored to normal in the AP + TEA and in delayed TEA groups - TEA reduced lactate concentration in the AP + TEA and delayed TEA group compared with AP - TEA reduced histologic injury compared with AP alone, without reaching statistical evidence - TEA induced a diminution of IL-6 plasmatic concentration compared with AP 7 days of follow-up...…”

Pain Management in Acute Pancreatitis

“…In this prospective single cohort study, epidural analgesia was thus able to produce considerable analgesic effect without any major rate of complications (10). Therefore, based on these promising observations, the results of the three clinical trials that are currently investigating the effect epidural analgesia on the course of AP are eagerly awaited (70).…”