**2. Oxidative stress associated with surgery and inhalation anesthetics**

Although the possibility that surgery increases oxidative stress has been suggested for several years [3, 4], how it develops remains unclear, especially during surgery. Analysis of intraoperative changes in the ferric‐reducing ability of plasma may lead to a breakthrough for elucidation of sur‐ gical oxidative stress, as the reduction of ferric irons to ferrous irons in plasma is a simple but sen‐ sitive indicator of the antioxidant potential of blood in clinical settings [5]. These changes can be measured by use of a biological antioxidant power (BAP) test with an FRAS 4 analyzer (Wismerll Co. Ltd. Tokyo, Japan), which is based on color changes of a solution containing a source of fer‐ ric ions adequately bound to a special chromogenic substrate at 505 nm when the ferric ions are reduced to ferrous ions according to antioxidant activity induced by addition of plasma.

Using this unique method, adult patients with ASA I‐II who underwent an open colectomy with sevoflurane anesthesia along with fentanyl and vecuronium were investigated. During surgery, the ferric reducing ability was significantly lowered, indicating that the colectomy procedure increased oxidative stress resulting in a reduction in the antioxidant ability of blood (**Figure 1**). To the best of our knowledge, these are the first reported findings to clearly demonstrate that surgery increases oxidative stress.

Regional Anesthesia: Advantages of Combined Use with General Anesthesia and Useful Tips for Improving... http://dx.doi.org/10.5772/66573 27

**Keywords:** regional anesthesia, antioxidant activity, neutrophils, AAPH, Phycoerythrin, protein kinase C, ultrasound‐guided nerve block, transversus abdominis plane block, intraoperative hemodynamics, caudal block, adjuvant, low molecular weight dextran, iPad, wireless image transmission, image position, radial artery catheterization

With recent advancements in ultrasound technology, nerve block procedures have become eas‐ ier and their accuracy improved [1, 2]. As a result, many regional anesthetic methods and tech‐ niques previously overlooked have been reevaluated, which has led to recent increased interest among anesthesiologists, with large numbers of papers and textbooks concerning regional anesthesia published during the past 10 years. However, the interrelationship between regional and general anesthesia has not been well‐elucidated. Regional anesthesia is not always per‐ formed as an independent procedure in daily practice; rather it is frequently included as part of a general anesthesia technique, thus a full understanding of its effects is important to evalu‐ ate usefulness in settings where general anesthesia is employed. In the present chapter, new perspectives regarding the interaction of regional anesthesia with general anesthesia as well as the use of ultrasound technology are discussed based on findings obtained by our research team. Discussions regarding the antioxidant activities of local anesthetics and their effects for stabilizing the hemodynamics of patients under general anesthesia, the best adjuvants for local anesthetics used for regional nerve block, a simple but important tip for improving the accu‐ racy and easiness of ultrasound‐guided procedures, and other related topics are included.

**2. Oxidative stress associated with surgery and inhalation anesthetics**

reduced to ferrous ions according to antioxidant activity induced by addition of plasma.

demonstrate that surgery increases oxidative stress.

Using this unique method, adult patients with ASA I‐II who underwent an open colectomy with sevoflurane anesthesia along with fentanyl and vecuronium were investigated. During surgery, the ferric reducing ability was significantly lowered, indicating that the colectomy procedure increased oxidative stress resulting in a reduction in the antioxidant ability of blood (**Figure 1**). To the best of our knowledge, these are the first reported findings to clearly

Although the possibility that surgery increases oxidative stress has been suggested for several years [3, 4], how it develops remains unclear, especially during surgery. Analysis of intraoperative changes in the ferric‐reducing ability of plasma may lead to a breakthrough for elucidation of sur‐ gical oxidative stress, as the reduction of ferric irons to ferrous irons in plasma is a simple but sen‐ sitive indicator of the antioxidant potential of blood in clinical settings [5]. These changes can be measured by use of a biological antioxidant power (BAP) test with an FRAS 4 analyzer (Wismerll Co. Ltd. Tokyo, Japan), which is based on color changes of a solution containing a source of fer‐ ric ions adequately bound to a special chromogenic substrate at 505 nm when the ferric ions are

**1. Introduction**

26 Current Topics in Anesthesiology

**Figure 1.** Plasma ferric‐reducing ability in 18 patients who underwent an open sigmoidectomy with sevoflurane anesthesia. Lower values indicate increased oxidative stress; thus, our findings demonstrated that surgery increases oxidative stress.

Oxidative stress may also be a key factor to determine patient surgical stress [5], and we investigated this issue in cases of cardiac surgery [6]. Preoperative oxidative stress was determined by measuring plasma hydroperoxide values using a d‐Rom test with an FRAS 4 analyzer, while the occurrence of major organ morbidity and mortality (MOMM) was also assessed. MOMM included death, deep sternal infection, reoperation, stroke, renal fail‐ ure requiring hemodialysis, and prolonged ventilation (>48 h). Our results showed that an elevated preoperative hydroperoxide level in cardiac surgery patients is an independent risk factor for severe postoperative complications, and its reliability to predict postopera‐ tive complications appeared to be better as compared to preoperative BNP values and the European system for cardiac operative risk evaluation (EuroSCORE). The optimal threshold value of hydroperoxide concentration to differentiate between patients with and without MOMM was found to be 450 UCarr (sensitivity, 87.0%; specificity, 81.9%). These findings indicated that preoperative oxidative stress is an important risk factor for postoperative complications. In addition, they suggested the therapeutic potential of antioxidant therapy in surgical patients, as antioxidant control may reduce surgical stress, thereby improving postoperative recovery.

On the other hand, the drug used for inhalation anesthesia also has an oxidant effect. We studied the effects of inhalation anesthetics on protein kinase C (PKC) activity, which has been implicated in regulation of cell secretion, modulation of membrane conductance, release of neurotransmit‐ ters, regulation of cytoplasmic Ca2+, functional modification of receptors, and other components of the signal transduction machinery [7–9]. As for neutrophils, the ability of PKC activators such as TPA to trigger superoxide generation suggests a role for protein phosphorylation in the mechanism of transmembrane signaling. In addition, purified PKC stimulates superoxide generation by the particulate fraction of neutrophils. Thus, activation of PKC is involved in the process of superoxide generation of neutrophils [10, 11]. Using partially purified PKC from rat brains, we found that halothane, a typical inhalation anesthetic [12], activated this enzyme and increased superoxide generation from neutrophils (**Figure 2**). Furthermore, other inhalation anesthetics have been reported to activate PKC in a similar manner according to their anesthetic potency (**Figure 3**) [7–9]. H‐7, a specific inhibitor of PKC, totally inhibited halothane‐induced PKC activation (**Figure 4**) and superoxide generation of neutrophils (**Figure 2**), confirming that the reaction developed via activation of PKC [9]. In addition to the findings in blood cells, it has been reported that sevoflurane, another typical inhalation anesthetic, increases the generation of reactive oxygen species (ROS) in isolated hearts [13]. Together, these findings strongly sug‐ gest negative effects of inhalation general anesthetics including an increase in oxidative stress in surgical patients.

**Figure 2.** Effects of halothane and H‐7 (l‐(5‐isoquinolinesulfonyl) methylpiperazine dihydrochloride) on superoxide generation by neutrophils. Superoxide generation was spectrophotometrically analyzed by measuring the reduction of cytochrome c at 550 nm with a reference wavelength of 540 nm. Neutrophils were obtained from a guinea pig using a method previously described [10], then 2 × 10<sup>6</sup> cells·ml−1 were incubated in KRP (Krebs‐Ringer phosphate solution) medium containing 1 mM Ca2+, 10 mM glucose, 25 μM cytochrome c, and 0.1 mM NaN<sup>3</sup> at 37°C. The concentrations of halothane, TPA (12‐O‐tetradecanoylphorbol‐13‐acetate), and H‐7 were 0.59 mM, 0.4 nM, and 100 μM, respectively. Halothane activated superoxide generation by neutrophils, whereas H‐7, a specific inhibitor of protein kinase c, inhibited that activation.

Regional Anesthesia: Advantages of Combined Use with General Anesthesia and Useful Tips for Improving... http://dx.doi.org/10.5772/66573 29

in regulation of cell secretion, modulation of membrane conductance, release of neurotransmit‐ ters, regulation of cytoplasmic Ca2+, functional modification of receptors, and other components of the signal transduction machinery [7–9]. As for neutrophils, the ability of PKC activators such as TPA to trigger superoxide generation suggests a role for protein phosphorylation in the mechanism of transmembrane signaling. In addition, purified PKC stimulates superoxide generation by the particulate fraction of neutrophils. Thus, activation of PKC is involved in the process of superoxide generation of neutrophils [10, 11]. Using partially purified PKC from rat brains, we found that halothane, a typical inhalation anesthetic [12], activated this enzyme and increased superoxide generation from neutrophils (**Figure 2**). Furthermore, other inhalation anesthetics have been reported to activate PKC in a similar manner according to their anesthetic potency (**Figure 3**) [7–9]. H‐7, a specific inhibitor of PKC, totally inhibited halothane‐induced PKC activation (**Figure 4**) and superoxide generation of neutrophils (**Figure 2**), confirming that the reaction developed via activation of PKC [9]. In addition to the findings in blood cells, it has been reported that sevoflurane, another typical inhalation anesthetic, increases the generation of reactive oxygen species (ROS) in isolated hearts [13]. Together, these findings strongly sug‐ gest negative effects of inhalation general anesthetics including an increase in oxidative stress

**Figure 2.** Effects of halothane and H‐7 (l‐(5‐isoquinolinesulfonyl) methylpiperazine dihydrochloride) on superoxide generation by neutrophils. Superoxide generation was spectrophotometrically analyzed by measuring the reduction of cytochrome c at 550 nm with a reference wavelength of 540 nm. Neutrophils were obtained from a guinea pig using

of halothane, TPA (12‐O‐tetradecanoylphorbol‐13‐acetate), and H‐7 were 0.59 mM, 0.4 nM, and 100 μM, respectively. Halothane activated superoxide generation by neutrophils, whereas H‐7, a specific inhibitor of protein kinase c, inhibited

medium containing 1 mM Ca2+, 10 mM glucose, 25 μM cytochrome c, and 0.1 mM NaN<sup>3</sup>

cells·ml−1 were incubated in KRP (Krebs‐Ringer phosphate solution)

at 37°C. The concentrations

in surgical patients.

28 Current Topics in Anesthesiology

a method previously described [10], then 2 × 10<sup>6</sup>

that activation.

**Figure 3.** Effects of inhalation anesthetics on PKC (protein kinase C) activity. Enzyme activity was assayed by determining the incorporation of 32P from [γ‐<sup>32</sup>P]ATP into calf thymus H1 histone (type III‐S) at 30°C over a period of 3 min in the presence of 1 μM Ca2+, 1 mM EGTA, and 100 μM phospholipid (phosphatidylcholine (PC)/phosphatidylserine (PS) (4:1 molar ratio) with various concentrations of inhalation anesthetics (halothane, enflurane, isoflurane). PKC was obtained from cerebral tissues of male Wistar/Slc rats and purified, using a previously described method [10]. Each of the examined inhalation anesthetics increased PKC activity in a dose‐dependent manner.

**Figure 4.** Effects of H‐7, specific inhibitor of PKC, on halothane‐activated PKC activity in the presence of low (1 μM) and high (0.3 mM) concentrations of Ca2+. The concentration of halothane was 20 mM, whereas the other experimental conditions were the same as described in **Figure 3**. H‐7 inhibited halothane‐activated PKC activity in a dose‐dependent manner.
