Effect of Intravenous Lidocaine on the Neuropathic Pain of Failed Back Surgery Syndrome

BACKGROUND: An intravenous infusion of lidocaine has been used on numerous occasions to produce analgesia in neuropathic pain. In the cases of failed back surgery syndrom, the pain generated as result of abnormal impulse from the dorsal root ganglion and spinal cord, for instance as a result of nerve injury may be particularly sensitive to lidocaine. The aim of the present study was to identify the effects of IV lidocaine on neuropathic pain items of FBSS. METHODS: The study was a randomized, prospective, double-blinded, crossover study involving eighteen patients with failed back surgery syndrome. The treatments were: 0.9% normal saline, lidocaine 1 mg/kg in 500 ml normal saline, and lidocaine 5 mg/kg in 500 ml normal saline over 60 minutes. The patients underwent infusions on three different appointments, at least two weeks apart. Thus all patients received all 3 treatments. Pain measurement was taken by visual analogue scale (VAS), and neuropathic pain questionnaire. RESULTS: Both lidocaine (1 mg/kg, 5 mg/kg) and placebo significantly reduced the intense, sharp, hot, dull, cold, sensitivity, itchy, unpleasant, deep and superficial of pain. The amount of change was not significantly different among either of the lidocaine and placebo, or among the lidocaine treatments themselves, for any of the pain responses, except sharp, dull, cold, unpleasant, and deep pain. And VAS was decreased during infusion in all 3 group and there were no difference among groups. CONCLUSIONS: This study shows that 1 mg/kg, or 5 mg/kg of IV lidocaine, and palcebo was effective in patients with neuropathic pain attributable to FBSS, but effect of licoaine did not differ from placebo saline.

Effect of superoxide on the development and maintenance of mechanical allodynia in a rat model of chronic post-ischemia pain / 대한마취과학회지

BACKGROUND: Reactive oxygen species and inflammatory responses contribute to the development of neuropathic pain. Superoxide serves to mediate cell signaling processes and tissue injury during inflammation. We examined the effects of superoxide on the development and maintenance of mechanical allodynia, as well as its contribution to central sensitization in a superoxide-rich animal model of neuropathic pain. METHODS: Chronic post-ischemia pain (CPIP) was induced via the left hindpaw ischemia for 3 h, followed by reperfusion. Superoxide dismutase (4,000 U/kg, i.p.) was administered either 5 min before ischemia (BI), 5 min before reperfusion (BR), or 3 days after reperfusion (3AR). Withdrawal thresholds of the four paws were measured to assess the mechanical allodynia and the effects of circulating xanthine oxidase (XO)-mediated superoxide production. In addition, we measured the levels of N-methyl D-aspartate receptor subunit 1 phosphorylation (p-NR1) in the ipsilateral and contralateral spinal cord (L4-6), by Western blotting, to examine the superoxide-mediated central sensitization. Superoxide production was assessed by allopurinol-sensitive, XO-mediated lipid peroxidation of the spinal cord and gastrocnemius muscles. RESULTS: Withdrawal thresholds of forepaws did not vary across the 7 days of testing. In the hindpaws, both ipsilateral and contralateral mechanical allodynia was most attenuated in the BR group, followed by the BI and 3AR groups. The degree of NR1 activation was in contrast to the changes in the withdrawal thresholds. CONCLUSIONS: These data suggest that superoxide is involved in the development and maintenance of mechanical allodynia, particularly via central sensitization in the spinal cord.

Effect of N-acetyl-cysteine on Allodynia in a Chronic Post-ischemia Pain Model of Rat

BACKGROUND: Complex regional pain syndrome type I (CRPS-I) is a clinical syndrome that is poorly understood and difficult to treat. Reactive oxygen species (ROS) and inflammatory responses may contribute to the development of CRPS-I. This study evaluated the effect of N-acetyl-cysteine (NAC) on both mechanical and cold allodynia in a rat CRPS-I model. METHODS: Male adult SD rats were used for the CRPS-I model that was produced following prolonged hindpaw ischemia/reperfusion. The rats were divided into 3 groups, Group O (-) (n = 8): rats without a tourniquet; Group O (+) (n = 8): rats received ischemic injury with a tourniquet on the hindpaw and they were reperfused 3 hours after the tourniquet application; and Group ON (+) (n = 8): rats received ischemic injury with a tourniquet ring on the hindpaw and they were reperfused 3 hours after the tourniquet application and they received intraperitoneal N-cetyl-ysteine (500 mg/kg) injection just after the tourniquet application and at 1 day and 2 days after the reperfusion. RESULTS: In the Group O (+), mechanical (von Frey hair) and cold (acetone exposure) allodynia were evident in the affected hindpaw as early as 1 day after reperfusion; this was extended for 2 weeks and it spread to the uninjured contralateral hindpaw. In the Group ON (+), the mechanical and cold allodynia were attenuated compared to those rats of Group O (+). CONCLUSIONS: NAC, a free radical scavenger, was able to reduce mechanical and cold allodynia in this model, and the generation of ROS is partly responsible for CRPS-I.

Change of Post-anesthetic Recovery Time after Colorectal Surgery with N-acetyl-cysteine Infusion / 대한마취과학회지

BACKGROUND: The gut is an important area for inflammatory responses. Gut manipulation during open laparotomy compared with laparoscopic surgery, increases the inflammatory responses. Laparoscopic assisted colectomy (LC) with less bowel manipulation might minimize the inflammatory responses and oxidative stress, and offer a faster postanesthetic recovery than an open colectomy (OC). This study evaluated the effect of N-acetyl-cysteine (NAC), an antioxidant, on the recovery after colectomy. METHODS: 116 colorectal tumor patients were reviewed retrospectively. The patients were divided into 3 groups; LC by surgeon A (A - L), OC by surgeon A (A - O) and OC by surgeon B (B - O). The postanesthetic recovery scores (PARS) were compared. In the prospective randomized controlled trial, the colorectal tumor patients were assigned to one of four groups; laparoscopic assisted colectomy (L - N) with NAC infusion (L + N), open colectomy (O - N) with NAC infusion (O + N). In the NAC groups, NAC (5 mg/kg/h) was infused after intubation to extubation. The PARS were compared. RESULTS: In the retrospective study, the time to reach 10 points, which satisfies the discharge criteria in the PACU, was significantly lower in the A-L group than in the other groups. In the prospective study, the time to 10 points was shorter in the O + N group than in the O-N group. NAC offered no added benefits to the L + N and L-N groups. CONCLUSIONS: NAC offered faster recovery in the OC group but not in the LC group.

Unusual Capnography due to Incorrect Assembly of Spring with Absorber Valve into Breathing Circuit - Experience of Normocarbia: A Case Report / 대한구급학회지

A focus on patient safety has heightened the awareness of pateint mornitoring. The importantce of clinical application of capnography continues to grow, as reflected by the increasing number of medical societies recommending its use. We recently encountered an abnormal capnography undergoing gastrectomy. It was noted that the waveform was not sustained zero-baseline formation as seen during inspiratory phase, immediately upsloping for expiratory plateau followed by inspiratoy downsloping as like a shape of curare cleft. But PaCO2 was within normal range. We found that the source of the problem was the incorrect (bottom up) assembly of spring with absorber valve into the CUBE, the circle breathing system of Dameca Ventilator. Spring with absorber valve divides CUBE circle into inspiratory and expiratory space. We concluded that the unusual capnography was resulted from the incorrect assembly of it, subsequently mixing of inspiratory and exhaled gases and rebreathing was occurred with the block of a gas flow to CO2 canister. After correcting assembly, the capnography was normalized.

The Effect of a Priming Dose of Atracurium on the Onset Time in Rapid Sequence Tracheal Intubation / 대한마취과학회지

BACKGROUND: Depolarizing muscle relaxant, frequently used for rapid sequence endotracheal intubation in clinical field, has serious complication that occur intermittently, such as, hyperkalemia, increased intraoccular pressure and sudden cardiac arrest, especially in infants and adolescents. So the priming principle, i.e., the administration of a subparalyzing dose of a nondepolarizing muscle relaxant (priming dose) prior to the intubating dose, was developed for rapid sequence endotracheal intubation with nondepolarizing muscle relaxant. However, the priming dose sometimes causes complications, such as, swallowing difficulty or pulmonary aspiration, and this can cause patient discomfort or fatal complications. In this study we examined proper atracurium priming dose and evaluated possible complications of priming doses. METHODS: One hundred patients, scheduled for elective surgery were randomly allocated into five groups according to the priming dose used (group 1; 0, group 2; 0.03, group 3; 0.06, group 4; 0.09, group 5; 0.12 mg/kg). Patients received a midazolam and fentanyl injection, the base line TOF ratio was measured, and an intubating dose was given. We also examined changes in vital sign for 20 minutes after injection and noted the time when the twitch height became zero (onset time). RESULTS: In group 1, the onset time was 107 +/- 22.9 sec, and in groups 4 and 5, the onset times were 85.0 +/- 15.6 and 69.9 +/- 19.3 sec, respectively. But, in group 5, some patients showed tachycardia and swallowing difficulty. CONCLUSIONS: The optimal priming dose of atracurium was determined as 0.09 mg/kg, in most cases, however patients sensitivity to the atracurium should be considered.

Analgesic Effect of Transplanted Adrenal Medullary Chromaffin Cells in Rats Spinal Cord / 대한마취과학회지

BACKGROUND: Despite of numerous researches on the mechanisms and new therapeutic methods of chronic pain, patients are still suffering even with the help of opioids. In recent years, however, with the development of molecular-biology cell transplantation gives us a new chance for treating intractable chronic pain. The major purpose of the present study was to determine if the chromaffin cells have robust analgesic effects in the spinal atlanto-occipital subarachnoid space even without nicotine stimulation. METHODS: In order to determine whether cultured bovine adrenal medullary chromaffin cells transplanted in the spinal cord can produce analgesic effects, we purified adrenal medullary chromaffin cells and implanted them into the subarachnoid space of rats' (n = 10) spinal cord without immunosuppression, and investigated the hot sensitivity of rats' hind-paw by a light-beam test. RESULTS: It was found that compared with the control group, hot response latency of the group which received adrenal medullary chromaffin cells had increased at 14 days and the analgesic efficacy was maintained for at least 3 months. CONCLUSIONS: Adrenal medullary chromaffin cells transplanted in the rats' spinal cord may provide a permanent and locally available source of neuropeptides for the relief of intractable pain. Furthermore, these kinds of analgesic effect even produced without any stimulation such as nicotine.

Changes of Hemodynamics and Nitric Oxide during Liver Ischemia/Reperfusion of Pig / 대한마취과학회지

BACKGROUND: Surgical hepatic inflow obstructions such as the Pringle Maneuver (PM) or hepatic vascular exclusion (HVE) can reduce bleeding during hepatic resection, but ischemia/reperfusion injury of the liver and systemic hemodynamic changes are also inevitable during and after PM or HVE. Nitric oxide plays a pivotal role in ischemia/reperfusion injury. We evaluated hemodynamic changes and changes of nitric oxide during liver ischemia/reperfusion injury excluding the effects of intestinal ischemia. METHODS: Liver ischemia was induced by clamping of the portal triad, infrahepatic and suprahepatic inferior vena cava for 90 minutes. To exclude the effects of intestinal ischemia during liver ischemia, portal and iliac venous blood was bypassed to the jugular vein using a pump. Hemodynamic parameters and nitric oxide were measured serially; before and during ischemia, and after reperfusion. RESULTS: Mean arterial blood pressure (MAP) was well-maintained during ischemia, but after reperfusion, MAP, cardiac output (CO) and stroke volume (SV) significantly decreased (35 - 40, 30 - 40 and 30%, respectively) postischemia. Compared to preischemia, systemic vascular resistance and heart rate did not change after reperfusion. Pulmonary vascular resistance and mean pulmonary arterial blood pressure significantly increased (220 - 250% and 60 - 70%) after reperfusion. Nitric oxide (NO) did not change until 20 minutes after reperfusion, but after 40 minutes reperfusion, NO significantly decreased (20%) compared to preischemia. CONCLUSIONS: After 90 minutes warm liver ischemia/reperfusion causes hypotension induced by decreased CO and SV. Increased PVR seems to be the cause of decreased CO and SV. NO-SVR interaction does not seem to be the cause of postreperfusion hypotension.